diff --git a/cmds/sensorservice/Android.mk b/cmds/sensorservice/Android.mk
new file mode 100644
index 0000000..0811be5
--- /dev/null
+++ b/cmds/sensorservice/Android.mk
@@ -0,0 +1,19 @@
+LOCAL_PATH:= $(call my-dir)
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES:= \
+	main_sensorservice.cpp
+
+LOCAL_SHARED_LIBRARIES := \
+	libsensorservice \
+	libbinder \
+	libutils
+
+LOCAL_C_INCLUDES := \
+	$(LOCAL_PATH)/../../services/sensorservice
+
+LOCAL_MODULE_TAGS := optional
+
+LOCAL_MODULE:= sensorservice
+
+include $(BUILD_EXECUTABLE)
diff --git a/cmds/sensorservice/main_sensorservice.cpp b/cmds/sensorservice/main_sensorservice.cpp
new file mode 100644
index 0000000..8610627
--- /dev/null
+++ b/cmds/sensorservice/main_sensorservice.cpp
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <binder/BinderService.h>
+#include <SensorService.h>
+
+using namespace android;
+
+int main(int argc, char** argv) {
+    SensorService::publishAndJoinThreadPool();
+    return 0;
+}
diff --git a/services/sensorservice/Android.mk b/services/sensorservice/Android.mk
new file mode 100644
index 0000000..6a302c0
--- /dev/null
+++ b/services/sensorservice/Android.mk
@@ -0,0 +1,31 @@
+LOCAL_PATH:= $(call my-dir)
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES:= \
+	CorrectedGyroSensor.cpp \
+    Fusion.cpp \
+    GravitySensor.cpp \
+    LinearAccelerationSensor.cpp \
+    OrientationSensor.cpp \
+    RotationVectorSensor.cpp \
+    SensorDevice.cpp \
+    SensorFusion.cpp \
+    SensorInterface.cpp \
+    SensorService.cpp \
+
+
+LOCAL_CFLAGS:= -DLOG_TAG=\"SensorService\"
+
+LOCAL_SHARED_LIBRARIES := \
+	libcutils \
+	libhardware \
+	libutils \
+	libbinder \
+	libui \
+	libgui
+
+
+
+LOCAL_MODULE:= libsensorservice
+
+include $(BUILD_SHARED_LIBRARY)
diff --git a/services/sensorservice/CorrectedGyroSensor.cpp b/services/sensorservice/CorrectedGyroSensor.cpp
new file mode 100644
index 0000000..1857443
--- /dev/null
+++ b/services/sensorservice/CorrectedGyroSensor.cpp
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+
+#include <hardware/sensors.h>
+
+#include "CorrectedGyroSensor.h"
+#include "SensorDevice.h"
+#include "SensorFusion.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+CorrectedGyroSensor::CorrectedGyroSensor(sensor_t const* list, size_t count)
+    : mSensorDevice(SensorDevice::getInstance()),
+      mSensorFusion(SensorFusion::getInstance())
+{
+    for (size_t i=0 ; i<count ; i++) {
+        if (list[i].type == SENSOR_TYPE_GYROSCOPE) {
+            mGyro = Sensor(list + i);
+            break;
+        }
+    }
+}
+
+bool CorrectedGyroSensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event)
+{
+    if (event.type == SENSOR_TYPE_GYROSCOPE) {
+        const vec3_t bias(mSensorFusion.getGyroBias());
+        *outEvent = event;
+        outEvent->data[0] -= bias.x;
+        outEvent->data[1] -= bias.y;
+        outEvent->data[2] -= bias.z;
+        outEvent->sensor = '_cgy';
+        return true;
+    }
+    return false;
+}
+
+status_t CorrectedGyroSensor::activate(void* ident, bool enabled) {
+    mSensorDevice.activate(this, mGyro.getHandle(), enabled);
+    return mSensorFusion.activate(this, enabled);
+}
+
+status_t CorrectedGyroSensor::setDelay(void* ident, int handle, int64_t ns) {
+    mSensorDevice.setDelay(this, mGyro.getHandle(), ns);
+    return mSensorFusion.setDelay(this, ns);
+}
+
+Sensor CorrectedGyroSensor::getSensor() const {
+    sensor_t hwSensor;
+    hwSensor.name       = "Corrected Gyroscope Sensor";
+    hwSensor.vendor     = "Google Inc.";
+    hwSensor.version    = 1;
+    hwSensor.handle     = '_cgy';
+    hwSensor.type       = SENSOR_TYPE_GYROSCOPE;
+    hwSensor.maxRange   = mGyro.getMaxValue();
+    hwSensor.resolution = mGyro.getResolution();
+    hwSensor.power      = mSensorFusion.getPowerUsage();
+    hwSensor.minDelay   = mGyro.getMinDelay();
+    Sensor sensor(&hwSensor);
+    return sensor;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
diff --git a/services/sensorservice/CorrectedGyroSensor.h b/services/sensorservice/CorrectedGyroSensor.h
new file mode 100644
index 0000000..3c49c08
--- /dev/null
+++ b/services/sensorservice/CorrectedGyroSensor.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_CORRECTED_GYRO_SENSOR_H
+#define ANDROID_CORRECTED_GYRO_SENSOR_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <gui/Sensor.h>
+
+#include "SensorInterface.h"
+
+// ---------------------------------------------------------------------------
+namespace android {
+// ---------------------------------------------------------------------------
+
+class SensorDevice;
+class SensorFusion;
+
+class CorrectedGyroSensor : public SensorInterface {
+    SensorDevice& mSensorDevice;
+    SensorFusion& mSensorFusion;
+    Sensor mGyro;
+
+public:
+    CorrectedGyroSensor(sensor_t const* list, size_t count);
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return true; }
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_CORRECTED_GYRO_SENSOR_H
diff --git a/services/sensorservice/Fusion.cpp b/services/sensorservice/Fusion.cpp
new file mode 100644
index 0000000..2b6b793
--- /dev/null
+++ b/services/sensorservice/Fusion.cpp
@@ -0,0 +1,464 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+
+#include <utils/Log.h>
+
+#include "Fusion.h"
+
+namespace android {
+
+// -----------------------------------------------------------------------
+
+/*
+ * gyroVAR gives the measured variance of the gyro's output per
+ * Hz (or variance at 1 Hz). This is an "intrinsic" parameter of the gyro,
+ * which is independent of the sampling frequency.
+ *
+ * The variance of gyro's output at a given sampling period can be
+ * calculated as:
+ *      variance(T) = gyroVAR / T
+ *
+ * The variance of the INTEGRATED OUTPUT at a given sampling period can be
+ * calculated as:
+ *       variance_integrate_output(T) = gyroVAR * T
+ *
+ */
+static const float gyroVAR = 1e-7;      // (rad/s)^2 / Hz
+static const float biasVAR = 1e-8;      // (rad/s)^2 / s (guessed)
+
+/*
+ * Standard deviations of accelerometer and magnetometer
+ */
+static const float accSTDEV  = 0.05f;   // m/s^2 (measured 0.08 / CDD 0.05)
+static const float magSTDEV  = 0.5f;    // uT    (measured 0.7  / CDD 0.5)
+
+static const float SYMMETRY_TOLERANCE = 1e-10f;
+
+/*
+ * Accelerometer updates will not be performed near free fall to avoid
+ * ill-conditioning and div by zeros.
+ * Threshhold: 10% of g, in m/s^2
+ */
+static const float FREE_FALL_THRESHOLD = 0.981f;
+static const float FREE_FALL_THRESHOLD_SQ =
+        FREE_FALL_THRESHOLD*FREE_FALL_THRESHOLD;
+
+/*
+ * The geomagnetic-field should be between 30uT and 60uT.
+ * Fields strengths greater than this likely indicate a local magnetic
+ * disturbance which we do not want to update into the fused frame.
+ */
+static const float MAX_VALID_MAGNETIC_FIELD = 100; // uT
+static const float MAX_VALID_MAGNETIC_FIELD_SQ =
+        MAX_VALID_MAGNETIC_FIELD*MAX_VALID_MAGNETIC_FIELD;
+
+/*
+ * Values of the field smaller than this should be ignored in fusion to avoid
+ * ill-conditioning. This state can happen with anomalous local magnetic
+ * disturbances canceling the Earth field.
+ */
+static const float MIN_VALID_MAGNETIC_FIELD = 10; // uT
+static const float MIN_VALID_MAGNETIC_FIELD_SQ =
+        MIN_VALID_MAGNETIC_FIELD*MIN_VALID_MAGNETIC_FIELD;
+
+/*
+ * If the cross product of two vectors has magnitude squared less than this,
+ * we reject it as invalid due to alignment of the vectors.
+ * This threshold is used to check for the case where the magnetic field sample
+ * is parallel to the gravity field, which can happen in certain places due
+ * to magnetic field disturbances.
+ */
+static const float MIN_VALID_CROSS_PRODUCT_MAG = 1.0e-3;
+static const float MIN_VALID_CROSS_PRODUCT_MAG_SQ =
+    MIN_VALID_CROSS_PRODUCT_MAG*MIN_VALID_CROSS_PRODUCT_MAG;
+
+// -----------------------------------------------------------------------
+
+template <typename TYPE, size_t C, size_t R>
+static mat<TYPE, R, R> scaleCovariance(
+        const mat<TYPE, C, R>& A,
+        const mat<TYPE, C, C>& P) {
+    // A*P*transpose(A);
+    mat<TYPE, R, R> APAt;
+    for (size_t r=0 ; r<R ; r++) {
+        for (size_t j=r ; j<R ; j++) {
+            double apat(0);
+            for (size_t c=0 ; c<C ; c++) {
+                double v(A[c][r]*P[c][c]*0.5);
+                for (size_t k=c+1 ; k<C ; k++)
+                    v += A[k][r] * P[c][k];
+                apat += 2 * v * A[c][j];
+            }
+            APAt[j][r] = apat;
+            APAt[r][j] = apat;
+        }
+    }
+    return APAt;
+}
+
+template <typename TYPE, typename OTHER_TYPE>
+static mat<TYPE, 3, 3> crossMatrix(const vec<TYPE, 3>& p, OTHER_TYPE diag) {
+    mat<TYPE, 3, 3> r;
+    r[0][0] = diag;
+    r[1][1] = diag;
+    r[2][2] = diag;
+    r[0][1] = p.z;
+    r[1][0] =-p.z;
+    r[0][2] =-p.y;
+    r[2][0] = p.y;
+    r[1][2] = p.x;
+    r[2][1] =-p.x;
+    return r;
+}
+
+
+template<typename TYPE, size_t SIZE>
+class Covariance {
+    mat<TYPE, SIZE, SIZE> mSumXX;
+    vec<TYPE, SIZE> mSumX;
+    size_t mN;
+public:
+    Covariance() : mSumXX(0.0f), mSumX(0.0f), mN(0) { }
+    void update(const vec<TYPE, SIZE>& x) {
+        mSumXX += x*transpose(x);
+        mSumX  += x;
+        mN++;
+    }
+    mat<TYPE, SIZE, SIZE> operator()() const {
+        const float N = 1.0f / mN;
+        return mSumXX*N - (mSumX*transpose(mSumX))*(N*N);
+    }
+    void reset() {
+        mN = 0;
+        mSumXX = 0;
+        mSumX = 0;
+    }
+    size_t getCount() const {
+        return mN;
+    }
+};
+
+// -----------------------------------------------------------------------
+
+Fusion::Fusion() {
+    Phi[0][1] = 0;
+    Phi[1][1] = 1;
+
+    Ba.x = 0;
+    Ba.y = 0;
+    Ba.z = 1;
+
+    Bm.x = 0;
+    Bm.y = 1;
+    Bm.z = 0;
+
+    x0 = 0;
+    x1 = 0;
+
+    init();
+}
+
+void Fusion::init() {
+    mInitState = 0;
+
+    mGyroRate = 0;
+
+    mCount[0] = 0;
+    mCount[1] = 0;
+    mCount[2] = 0;
+
+    mData = 0;
+}
+
+void Fusion::initFusion(const vec4_t& q, float dT)
+{
+    // initial estimate: E{ x(t0) }
+    x0 = q;
+    x1 = 0;
+
+    // process noise covariance matrix: G.Q.Gt, with
+    //
+    //  G = | -1 0 |        Q = | q00 q10 |
+    //      |  0 1 |            | q01 q11 |
+    //
+    // q00 = sv^2.dt + 1/3.su^2.dt^3
+    // q10 = q01 = 1/2.su^2.dt^2
+    // q11 = su^2.dt
+    //
+
+    const float dT2 = dT*dT;
+    const float dT3 = dT2*dT;
+
+    // variance of integrated output at 1/dT Hz (random drift)
+    const float q00 = gyroVAR * dT + 0.33333f * biasVAR * dT3;
+
+    // variance of drift rate ramp
+    const float q11 = biasVAR * dT;
+    const float q10 = 0.5f * biasVAR * dT2;
+    const float q01 = q10;
+
+    GQGt[0][0] =  q00;      // rad^2
+    GQGt[1][0] = -q10;
+    GQGt[0][1] = -q01;
+    GQGt[1][1] =  q11;      // (rad/s)^2
+
+    // initial covariance: Var{ x(t0) }
+    // TODO: initialize P correctly
+    P = 0;
+
+    // it is unclear how to set the initial covariance. It does affect
+    // how quickly the fusion converges. Experimentally it would take
+    // about 10 seconds at 200 Hz to estimate the gyro-drift with an
+    // initial covariance of 0, and about a second with an initial covariance
+    // of about 1 deg/s.
+    const float covv = 0;
+    const float covu = 0.5f * (float(M_PI) / 180);
+    mat33_t& Pv = P[0][0];
+    Pv[0][0] = covv;
+    Pv[1][1] = covv;
+    Pv[2][2] = covv;
+    mat33_t& Pu = P[1][1];
+    Pu[0][0] = covu;
+    Pu[1][1] = covu;
+    Pu[2][2] = covu;
+}
+
+bool Fusion::hasEstimate() const {
+    return (mInitState == (MAG|ACC|GYRO));
+}
+
+bool Fusion::checkInitComplete(int what, const vec3_t& d, float dT) {
+    if (hasEstimate())
+        return true;
+
+    if (what == ACC) {
+        mData[0] += d * (1/length(d));
+        mCount[0]++;
+        mInitState |= ACC;
+    } else if (what == MAG) {
+        mData[1] += d * (1/length(d));
+        mCount[1]++;
+        mInitState |= MAG;
+    } else if (what == GYRO) {
+        mGyroRate = dT;
+        mData[2] += d*dT;
+        mCount[2]++;
+        if (mCount[2] == 64) {
+            // 64 samples is good enough to estimate the gyro drift and
+            // doesn't take too much time.
+            mInitState |= GYRO;
+        }
+    }
+
+    if (mInitState == (MAG|ACC|GYRO)) {
+        // Average all the values we collected so far
+        mData[0] *= 1.0f/mCount[0];
+        mData[1] *= 1.0f/mCount[1];
+        mData[2] *= 1.0f/mCount[2];
+
+        // calculate the MRPs from the data collection, this gives us
+        // a rough estimate of our initial state
+        mat33_t R;
+        vec3_t up(mData[0]);
+        vec3_t east(cross_product(mData[1], up));
+        east *= 1/length(east);
+        vec3_t north(cross_product(up, east));
+        R << east << north << up;
+        const vec4_t q = matrixToQuat(R);
+
+        initFusion(q, mGyroRate);
+    }
+
+    return false;
+}
+
+void Fusion::handleGyro(const vec3_t& w, float dT) {
+    if (!checkInitComplete(GYRO, w, dT))
+        return;
+
+    predict(w, dT);
+}
+
+status_t Fusion::handleAcc(const vec3_t& a) {
+    // ignore acceleration data if we're close to free-fall
+    if (length_squared(a) < FREE_FALL_THRESHOLD_SQ) {
+        return BAD_VALUE;
+    }
+
+    if (!checkInitComplete(ACC, a))
+        return BAD_VALUE;
+
+    const float l = 1/length(a);
+    update(a*l, Ba, accSTDEV*l);
+    return NO_ERROR;
+}
+
+status_t Fusion::handleMag(const vec3_t& m) {
+    // the geomagnetic-field should be between 30uT and 60uT
+    // reject if too large to avoid spurious magnetic sources
+    const float magFieldSq = length_squared(m);
+    if (magFieldSq > MAX_VALID_MAGNETIC_FIELD_SQ) {
+        return BAD_VALUE;
+    } else if (magFieldSq < MIN_VALID_MAGNETIC_FIELD_SQ) {
+        // Also reject if too small since we will get ill-defined (zero mag)
+        // cross-products below
+        return BAD_VALUE;
+    }
+
+    if (!checkInitComplete(MAG, m))
+        return BAD_VALUE;
+
+    // Orthogonalize the magnetic field to the gravity field, mapping it into
+    // tangent to Earth.
+    const vec3_t up( getRotationMatrix() * Ba );
+    const vec3_t east( cross_product(m, up) );
+
+    // If the m and up vectors align, the cross product magnitude will
+    // approach 0.
+    // Reject this case as well to avoid div by zero problems and
+    // ill-conditioning below.
+    if (length_squared(east) < MIN_VALID_CROSS_PRODUCT_MAG_SQ) {
+        return BAD_VALUE;
+    }
+
+    // If we have created an orthogonal magnetic field successfully,
+    // then pass it in as the update.
+    vec3_t north( cross_product(up, east) );
+
+    const float l = 1 / length(north);
+    north *= l;
+
+    update(north, Bm, magSTDEV*l);
+    return NO_ERROR;
+}
+
+void Fusion::checkState() {
+    // P needs to stay positive semidefinite or the fusion diverges. When we
+    // detect divergence, we reset the fusion.
+    // TODO(braun): Instead, find the reason for the divergence and fix it.
+
+    if (!isPositiveSemidefinite(P[0][0], SYMMETRY_TOLERANCE) ||
+        !isPositiveSemidefinite(P[1][1], SYMMETRY_TOLERANCE)) {
+        ALOGW("Sensor fusion diverged; resetting state.");
+        P = 0;
+    }
+}
+
+vec4_t Fusion::getAttitude() const {
+    return x0;
+}
+
+vec3_t Fusion::getBias() const {
+    return x1;
+}
+
+mat33_t Fusion::getRotationMatrix() const {
+    return quatToMatrix(x0);
+}
+
+mat34_t Fusion::getF(const vec4_t& q) {
+    mat34_t F;
+
+    // This is used to compute the derivative of q
+    // F = | [q.xyz]x |
+    //     |  -q.xyz  |
+
+    F[0].x = q.w;   F[1].x =-q.z;   F[2].x = q.y;
+    F[0].y = q.z;   F[1].y = q.w;   F[2].y =-q.x;
+    F[0].z =-q.y;   F[1].z = q.x;   F[2].z = q.w;
+    F[0].w =-q.x;   F[1].w =-q.y;   F[2].w =-q.z;
+    return F;
+}
+
+void Fusion::predict(const vec3_t& w, float dT) {
+    const vec4_t q  = x0;
+    const vec3_t b  = x1;
+    const vec3_t we = w - b;
+    const vec4_t dq = getF(q)*((0.5f*dT)*we);
+    x0 = normalize_quat(q + dq);
+
+    // P(k+1) = F*P(k)*Ft + G*Q*Gt
+
+    //  Phi = | Phi00 Phi10 |
+    //        |   0     1   |
+    const mat33_t I33(1);
+    const mat33_t I33dT(dT);
+    const mat33_t wx(crossMatrix(we, 0));
+    const mat33_t wx2(wx*wx);
+    const float lwedT = length(we)*dT;
+    const float ilwe = 1/length(we);
+    const float k0 = (1-cosf(lwedT))*(ilwe*ilwe);
+    const float k1 = sinf(lwedT);
+
+    Phi[0][0] = I33 - wx*(k1*ilwe) + wx2*k0;
+    Phi[1][0] = wx*k0 - I33dT - wx2*(ilwe*ilwe*ilwe)*(lwedT-k1);
+
+    P = Phi*P*transpose(Phi) + GQGt;
+
+    checkState();
+}
+
+void Fusion::update(const vec3_t& z, const vec3_t& Bi, float sigma) {
+    vec4_t q(x0);
+    // measured vector in body space: h(p) = A(p)*Bi
+    const mat33_t A(quatToMatrix(q));
+    const vec3_t Bb(A*Bi);
+
+    // Sensitivity matrix H = dh(p)/dp
+    // H = [ L 0 ]
+    const mat33_t L(crossMatrix(Bb, 0));
+
+    // gain...
+    // K = P*Ht / [H*P*Ht + R]
+    vec<mat33_t, 2> K;
+    const mat33_t R(sigma*sigma);
+    const mat33_t S(scaleCovariance(L, P[0][0]) + R);
+    const mat33_t Si(invert(S));
+    const mat33_t LtSi(transpose(L)*Si);
+    K[0] = P[0][0] * LtSi;
+    K[1] = transpose(P[1][0])*LtSi;
+
+    // update...
+    // P = (I-K*H) * P
+    // P -= K*H*P
+    // | K0 | * | L 0 | * P = | K0*L  0 | * | P00  P10 | = | K0*L*P00  K0*L*P10 |
+    // | K1 |                 | K1*L  0 |   | P01  P11 |   | K1*L*P00  K1*L*P10 |
+    // Note: the Joseph form is numerically more stable and given by:
+    //     P = (I-KH) * P * (I-KH)' + K*R*R'
+    const mat33_t K0L(K[0] * L);
+    const mat33_t K1L(K[1] * L);
+    P[0][0] -= K0L*P[0][0];
+    P[1][1] -= K1L*P[1][0];
+    P[1][0] -= K0L*P[1][0];
+    P[0][1] = transpose(P[1][0]);
+
+    const vec3_t e(z - Bb);
+    const vec3_t dq(K[0]*e);
+    const vec3_t db(K[1]*e);
+
+    q += getF(q)*(0.5f*dq);
+    x0 = normalize_quat(q);
+    x1 += db;
+
+    checkState();
+}
+
+// -----------------------------------------------------------------------
+
+}; // namespace android
+
diff --git a/services/sensorservice/Fusion.h b/services/sensorservice/Fusion.h
new file mode 100644
index 0000000..7062999
--- /dev/null
+++ b/services/sensorservice/Fusion.h
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_FUSION_H
+#define ANDROID_FUSION_H
+
+#include <utils/Errors.h>
+
+#include "quat.h"
+#include "mat.h"
+#include "vec.h"
+
+namespace android {
+
+typedef mat<float, 3, 4> mat34_t;
+
+class Fusion {
+    /*
+     * the state vector is made of two sub-vector containing respectively:
+     * - modified Rodrigues parameters
+     * - the estimated gyro bias
+     */
+    quat_t  x0;
+    vec3_t  x1;
+
+    /*
+     * the predicated covariance matrix is made of 4 3x3 sub-matrices and it is
+     * semi-definite positive.
+     *
+     * P = | P00  P10 | = | P00  P10 |
+     *     | P01  P11 |   | P10t P11 |
+     *
+     * Since P01 = transpose(P10), the code below never calculates or
+     * stores P01.
+     */
+    mat<mat33_t, 2, 2> P;
+
+    /*
+     * the process noise covariance matrix
+     */
+    mat<mat33_t, 2, 2> GQGt;
+
+public:
+    Fusion();
+    void init();
+    void handleGyro(const vec3_t& w, float dT);
+    status_t handleAcc(const vec3_t& a);
+    status_t handleMag(const vec3_t& m);
+    vec4_t getAttitude() const;
+    vec3_t getBias() const;
+    mat33_t getRotationMatrix() const;
+    bool hasEstimate() const;
+
+private:
+    mat<mat33_t, 2, 2> Phi;
+    vec3_t Ba, Bm;
+    uint32_t mInitState;
+    float mGyroRate;
+    vec<vec3_t, 3> mData;
+    size_t mCount[3];
+    enum { ACC=0x1, MAG=0x2, GYRO=0x4 };
+    bool checkInitComplete(int, const vec3_t& w, float d = 0);
+    void initFusion(const vec4_t& q0, float dT);
+    void checkState();
+    void predict(const vec3_t& w, float dT);
+    void update(const vec3_t& z, const vec3_t& Bi, float sigma);
+    static mat34_t getF(const vec4_t& p);
+};
+
+}; // namespace android
+
+#endif // ANDROID_FUSION_H
diff --git a/services/sensorservice/GravitySensor.cpp b/services/sensorservice/GravitySensor.cpp
new file mode 100644
index 0000000..c57715f
--- /dev/null
+++ b/services/sensorservice/GravitySensor.cpp
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+
+#include <hardware/sensors.h>
+
+#include "GravitySensor.h"
+#include "SensorDevice.h"
+#include "SensorFusion.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+GravitySensor::GravitySensor(sensor_t const* list, size_t count)
+    : mSensorDevice(SensorDevice::getInstance()),
+      mSensorFusion(SensorFusion::getInstance())
+{
+    for (size_t i=0 ; i<count ; i++) {
+        if (list[i].type == SENSOR_TYPE_ACCELEROMETER) {
+            mAccelerometer = Sensor(list + i);
+            break;
+        }
+    }
+}
+
+bool GravitySensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event)
+{
+    const static double NS2S = 1.0 / 1000000000.0;
+    if (event.type == SENSOR_TYPE_ACCELEROMETER) {
+        vec3_t g;
+        if (!mSensorFusion.hasEstimate())
+            return false;
+        const mat33_t R(mSensorFusion.getRotationMatrix());
+        // FIXME: we need to estimate the length of gravity because
+        // the accelerometer may have a small scaling error. This
+        // translates to an offset in the linear-acceleration sensor.
+        g = R[2] * GRAVITY_EARTH;
+
+        *outEvent = event;
+        outEvent->data[0] = g.x;
+        outEvent->data[1] = g.y;
+        outEvent->data[2] = g.z;
+        outEvent->sensor = '_grv';
+        outEvent->type = SENSOR_TYPE_GRAVITY;
+        return true;
+    }
+    return false;
+}
+
+status_t GravitySensor::activate(void* ident, bool enabled) {
+    return mSensorFusion.activate(this, enabled);
+}
+
+status_t GravitySensor::setDelay(void* ident, int handle, int64_t ns) {
+    return mSensorFusion.setDelay(this, ns);
+}
+
+Sensor GravitySensor::getSensor() const {
+    sensor_t hwSensor;
+    hwSensor.name       = "Gravity Sensor";
+    hwSensor.vendor     = "Google Inc.";
+    hwSensor.version    = 3;
+    hwSensor.handle     = '_grv';
+    hwSensor.type       = SENSOR_TYPE_GRAVITY;
+    hwSensor.maxRange   = GRAVITY_EARTH * 2;
+    hwSensor.resolution = mAccelerometer.getResolution();
+    hwSensor.power      = mSensorFusion.getPowerUsage();
+    hwSensor.minDelay   = mSensorFusion.getMinDelay();
+    Sensor sensor(&hwSensor);
+    return sensor;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
diff --git a/services/sensorservice/GravitySensor.h b/services/sensorservice/GravitySensor.h
new file mode 100644
index 0000000..ac177c4
--- /dev/null
+++ b/services/sensorservice/GravitySensor.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_GRAVITY_SENSOR_H
+#define ANDROID_GRAVITY_SENSOR_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <gui/Sensor.h>
+
+#include "SensorInterface.h"
+
+// ---------------------------------------------------------------------------
+namespace android {
+// ---------------------------------------------------------------------------
+
+class SensorDevice;
+class SensorFusion;
+
+class GravitySensor : public SensorInterface {
+    SensorDevice& mSensorDevice;
+    SensorFusion& mSensorFusion;
+    Sensor mAccelerometer;
+
+public:
+    GravitySensor(sensor_t const* list, size_t count);
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return true; }
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_GRAVITY_SENSOR_H
diff --git a/services/sensorservice/LinearAccelerationSensor.cpp b/services/sensorservice/LinearAccelerationSensor.cpp
new file mode 100644
index 0000000..f0054f2
--- /dev/null
+++ b/services/sensorservice/LinearAccelerationSensor.cpp
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+
+#include <hardware/sensors.h>
+
+#include "LinearAccelerationSensor.h"
+#include "SensorDevice.h"
+#include "SensorFusion.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+LinearAccelerationSensor::LinearAccelerationSensor(sensor_t const* list, size_t count)
+    : mSensorDevice(SensorDevice::getInstance()),
+      mGravitySensor(list, count)
+{
+}
+
+bool LinearAccelerationSensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event)
+{
+    bool result = mGravitySensor.process(outEvent, event);
+    if (result && event.type == SENSOR_TYPE_ACCELEROMETER) {
+        outEvent->data[0] = event.acceleration.x - outEvent->data[0];
+        outEvent->data[1] = event.acceleration.y - outEvent->data[1];
+        outEvent->data[2] = event.acceleration.z - outEvent->data[2];
+        outEvent->sensor = '_lin';
+        outEvent->type = SENSOR_TYPE_LINEAR_ACCELERATION;
+        return true;
+    }
+    return false;
+}
+
+status_t LinearAccelerationSensor::activate(void* ident, bool enabled) {
+    return mGravitySensor.activate(this, enabled);
+}
+
+status_t LinearAccelerationSensor::setDelay(void* ident, int handle, int64_t ns) {
+    return mGravitySensor.setDelay(this, handle, ns);
+}
+
+Sensor LinearAccelerationSensor::getSensor() const {
+    Sensor gsensor(mGravitySensor.getSensor());
+    sensor_t hwSensor;
+    hwSensor.name       = "Linear Acceleration Sensor";
+    hwSensor.vendor     = "Google Inc.";
+    hwSensor.version    = gsensor.getVersion();
+    hwSensor.handle     = '_lin';
+    hwSensor.type       = SENSOR_TYPE_LINEAR_ACCELERATION;
+    hwSensor.maxRange   = gsensor.getMaxValue();
+    hwSensor.resolution = gsensor.getResolution();
+    hwSensor.power      = gsensor.getPowerUsage();
+    hwSensor.minDelay   = gsensor.getMinDelay();
+    Sensor sensor(&hwSensor);
+    return sensor;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
diff --git a/services/sensorservice/LinearAccelerationSensor.h b/services/sensorservice/LinearAccelerationSensor.h
new file mode 100644
index 0000000..5deb24f
--- /dev/null
+++ b/services/sensorservice/LinearAccelerationSensor.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_LINEAR_ACCELERATION_SENSOR_H
+#define ANDROID_LINEAR_ACCELERATION_SENSOR_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <gui/Sensor.h>
+
+#include "SensorInterface.h"
+#include "GravitySensor.h"
+
+// ---------------------------------------------------------------------------
+namespace android {
+// ---------------------------------------------------------------------------
+
+class SensorDevice;
+class SensorFusion;
+
+class LinearAccelerationSensor : public SensorInterface {
+    SensorDevice& mSensorDevice;
+    GravitySensor mGravitySensor;
+
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+public:
+    LinearAccelerationSensor(sensor_t const* list, size_t count);
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return true; }
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_LINEAR_ACCELERATION_SENSOR_H
diff --git a/services/sensorservice/OrientationSensor.cpp b/services/sensorservice/OrientationSensor.cpp
new file mode 100644
index 0000000..037adaa
--- /dev/null
+++ b/services/sensorservice/OrientationSensor.cpp
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+
+#include <hardware/sensors.h>
+
+#include "OrientationSensor.h"
+#include "SensorDevice.h"
+#include "SensorFusion.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+OrientationSensor::OrientationSensor()
+    : mSensorDevice(SensorDevice::getInstance()),
+      mSensorFusion(SensorFusion::getInstance())
+{
+}
+
+bool OrientationSensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event)
+{
+    if (event.type == SENSOR_TYPE_ACCELEROMETER) {
+        if (mSensorFusion.hasEstimate()) {
+            vec3_t g;
+            const float rad2deg = 180 / M_PI;
+            const mat33_t R(mSensorFusion.getRotationMatrix());
+            g[0] = atan2f(-R[1][0], R[0][0])    * rad2deg;
+            g[1] = atan2f(-R[2][1], R[2][2])    * rad2deg;
+            g[2] = asinf ( R[2][0])             * rad2deg;
+            if (g[0] < 0)
+                g[0] += 360;
+
+            *outEvent = event;
+            outEvent->orientation.azimuth = g.x;
+            outEvent->orientation.pitch   = g.y;
+            outEvent->orientation.roll    = g.z;
+            outEvent->orientation.status  = SENSOR_STATUS_ACCURACY_HIGH;
+            outEvent->sensor = '_ypr';
+            outEvent->type = SENSOR_TYPE_ORIENTATION;
+            return true;
+        }
+    }
+    return false;
+}
+
+status_t OrientationSensor::activate(void* ident, bool enabled) {
+    return mSensorFusion.activate(this, enabled);
+}
+
+status_t OrientationSensor::setDelay(void* ident, int handle, int64_t ns) {
+    return mSensorFusion.setDelay(this, ns);
+}
+
+Sensor OrientationSensor::getSensor() const {
+    sensor_t hwSensor;
+    hwSensor.name       = "Orientation Sensor";
+    hwSensor.vendor     = "Google Inc.";
+    hwSensor.version    = 1;
+    hwSensor.handle     = '_ypr';
+    hwSensor.type       = SENSOR_TYPE_ORIENTATION;
+    hwSensor.maxRange   = 360.0f;
+    hwSensor.resolution = 1.0f/256.0f; // FIXME: real value here
+    hwSensor.power      = mSensorFusion.getPowerUsage();
+    hwSensor.minDelay   = mSensorFusion.getMinDelay();
+    Sensor sensor(&hwSensor);
+    return sensor;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
diff --git a/services/sensorservice/OrientationSensor.h b/services/sensorservice/OrientationSensor.h
new file mode 100644
index 0000000..855949d
--- /dev/null
+++ b/services/sensorservice/OrientationSensor.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_ORIENTATION_SENSOR_H
+#define ANDROID_ORIENTATION_SENSOR_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <gui/Sensor.h>
+
+#include "SensorInterface.h"
+
+// ---------------------------------------------------------------------------
+namespace android {
+// ---------------------------------------------------------------------------
+
+class SensorDevice;
+class SensorFusion;
+
+class OrientationSensor : public SensorInterface {
+    SensorDevice& mSensorDevice;
+    SensorFusion& mSensorFusion;
+
+public:
+    OrientationSensor();
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return true; }
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_ORIENTATION_SENSOR_H
diff --git a/services/sensorservice/RotationVectorSensor.cpp b/services/sensorservice/RotationVectorSensor.cpp
new file mode 100644
index 0000000..5ea9568
--- /dev/null
+++ b/services/sensorservice/RotationVectorSensor.cpp
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+
+#include <hardware/sensors.h>
+
+#include "RotationVectorSensor.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+RotationVectorSensor::RotationVectorSensor()
+    : mSensorDevice(SensorDevice::getInstance()),
+      mSensorFusion(SensorFusion::getInstance())
+{
+}
+
+bool RotationVectorSensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event)
+{
+    if (event.type == SENSOR_TYPE_ACCELEROMETER) {
+        if (mSensorFusion.hasEstimate()) {
+            const vec4_t q(mSensorFusion.getAttitude());
+            *outEvent = event;
+            outEvent->data[0] = q.x;
+            outEvent->data[1] = q.y;
+            outEvent->data[2] = q.z;
+            outEvent->data[3] = q.w;
+            outEvent->sensor = '_rov';
+            outEvent->type = SENSOR_TYPE_ROTATION_VECTOR;
+            return true;
+        }
+    }
+    return false;
+}
+
+status_t RotationVectorSensor::activate(void* ident, bool enabled) {
+    return mSensorFusion.activate(this, enabled);
+}
+
+status_t RotationVectorSensor::setDelay(void* ident, int handle, int64_t ns) {
+    return mSensorFusion.setDelay(this, ns);
+}
+
+Sensor RotationVectorSensor::getSensor() const {
+    sensor_t hwSensor;
+    hwSensor.name       = "Rotation Vector Sensor";
+    hwSensor.vendor     = "Google Inc.";
+    hwSensor.version    = 3;
+    hwSensor.handle     = '_rov';
+    hwSensor.type       = SENSOR_TYPE_ROTATION_VECTOR;
+    hwSensor.maxRange   = 1;
+    hwSensor.resolution = 1.0f / (1<<24);
+    hwSensor.power      = mSensorFusion.getPowerUsage();
+    hwSensor.minDelay   = mSensorFusion.getMinDelay();
+    Sensor sensor(&hwSensor);
+    return sensor;
+}
+
+// ---------------------------------------------------------------------------
+
+GyroDriftSensor::GyroDriftSensor()
+    : mSensorDevice(SensorDevice::getInstance()),
+      mSensorFusion(SensorFusion::getInstance())
+{
+}
+
+bool GyroDriftSensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event)
+{
+    if (event.type == SENSOR_TYPE_ACCELEROMETER) {
+        if (mSensorFusion.hasEstimate()) {
+            const vec3_t b(mSensorFusion.getGyroBias());
+            *outEvent = event;
+            outEvent->data[0] = b.x;
+            outEvent->data[1] = b.y;
+            outEvent->data[2] = b.z;
+            outEvent->sensor = '_gbs';
+            outEvent->type = SENSOR_TYPE_ACCELEROMETER;
+            return true;
+        }
+    }
+    return false;
+}
+
+status_t GyroDriftSensor::activate(void* ident, bool enabled) {
+    return mSensorFusion.activate(this, enabled);
+}
+
+status_t GyroDriftSensor::setDelay(void* ident, int handle, int64_t ns) {
+    return mSensorFusion.setDelay(this, ns);
+}
+
+Sensor GyroDriftSensor::getSensor() const {
+    sensor_t hwSensor;
+    hwSensor.name       = "Gyroscope Bias (debug)";
+    hwSensor.vendor     = "Google Inc.";
+    hwSensor.version    = 1;
+    hwSensor.handle     = '_gbs';
+    hwSensor.type       = SENSOR_TYPE_ACCELEROMETER;
+    hwSensor.maxRange   = 1;
+    hwSensor.resolution = 1.0f / (1<<24);
+    hwSensor.power      = mSensorFusion.getPowerUsage();
+    hwSensor.minDelay   = mSensorFusion.getMinDelay();
+    Sensor sensor(&hwSensor);
+    return sensor;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
diff --git a/services/sensorservice/RotationVectorSensor.h b/services/sensorservice/RotationVectorSensor.h
new file mode 100644
index 0000000..bb97fe1
--- /dev/null
+++ b/services/sensorservice/RotationVectorSensor.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_ROTATION_VECTOR_SENSOR_H
+#define ANDROID_ROTATION_VECTOR_SENSOR_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <gui/Sensor.h>
+
+#include "SensorDevice.h"
+#include "SensorInterface.h"
+
+#include "Fusion.h"
+#include "SensorFusion.h"
+
+// ---------------------------------------------------------------------------
+namespace android {
+// ---------------------------------------------------------------------------
+
+class RotationVectorSensor : public SensorInterface {
+    SensorDevice& mSensorDevice;
+    SensorFusion& mSensorFusion;
+
+public:
+    RotationVectorSensor();
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return true; }
+};
+
+class GyroDriftSensor : public SensorInterface {
+    SensorDevice& mSensorDevice;
+    SensorFusion& mSensorFusion;
+
+public:
+    GyroDriftSensor();
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return true; }
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_ROTATION_VECTOR_SENSOR_H
diff --git a/services/sensorservice/SensorDevice.cpp b/services/sensorservice/SensorDevice.cpp
new file mode 100644
index 0000000..2244a86
--- /dev/null
+++ b/services/sensorservice/SensorDevice.cpp
@@ -0,0 +1,282 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Atomic.h>
+#include <utils/Errors.h>
+#include <utils/Singleton.h>
+
+#include <binder/BinderService.h>
+#include <binder/Parcel.h>
+#include <binder/IServiceManager.h>
+
+#include <hardware/sensors.h>
+
+#include "SensorDevice.h"
+#include "SensorService.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+class BatteryService : public Singleton<BatteryService> {
+    static const int TRANSACTION_noteStartSensor = IBinder::FIRST_CALL_TRANSACTION + 3;
+    static const int TRANSACTION_noteStopSensor = IBinder::FIRST_CALL_TRANSACTION + 4;
+    static const String16 DESCRIPTOR;
+
+    friend class Singleton<BatteryService>;
+    sp<IBinder> mBatteryStatService;
+
+    BatteryService() {
+        const sp<IServiceManager> sm(defaultServiceManager());
+        if (sm != NULL) {
+            const String16 name("batteryinfo");
+            mBatteryStatService = sm->getService(name);
+        }
+    }
+
+    status_t noteStartSensor(int uid, int handle) {
+        Parcel data, reply;
+        data.writeInterfaceToken(DESCRIPTOR);
+        data.writeInt32(uid);
+        data.writeInt32(handle);
+        status_t err = mBatteryStatService->transact(
+                TRANSACTION_noteStartSensor, data, &reply, 0);
+        err = reply.readExceptionCode();
+        return err;
+    }
+
+    status_t noteStopSensor(int uid, int handle) {
+        Parcel data, reply;
+        data.writeInterfaceToken(DESCRIPTOR);
+        data.writeInt32(uid);
+        data.writeInt32(handle);
+        status_t err = mBatteryStatService->transact(
+                TRANSACTION_noteStopSensor, data, &reply, 0);
+        err = reply.readExceptionCode();
+        return err;
+    }
+
+public:
+    void enableSensor(int handle) {
+        if (mBatteryStatService != 0) {
+            int uid = IPCThreadState::self()->getCallingUid();
+            int64_t identity = IPCThreadState::self()->clearCallingIdentity();
+            noteStartSensor(uid, handle);
+            IPCThreadState::self()->restoreCallingIdentity(identity);
+        }
+    }
+    void disableSensor(int handle) {
+        if (mBatteryStatService != 0) {
+            int uid = IPCThreadState::self()->getCallingUid();
+            int64_t identity = IPCThreadState::self()->clearCallingIdentity();
+            noteStopSensor(uid, handle);
+            IPCThreadState::self()->restoreCallingIdentity(identity);
+        }
+    }
+};
+
+const String16 BatteryService::DESCRIPTOR("com.android.internal.app.IBatteryStats");
+
+ANDROID_SINGLETON_STATIC_INSTANCE(BatteryService)
+
+// ---------------------------------------------------------------------------
+
+ANDROID_SINGLETON_STATIC_INSTANCE(SensorDevice)
+
+SensorDevice::SensorDevice()
+    :  mSensorDevice(0),
+       mSensorModule(0)
+{
+    status_t err = hw_get_module(SENSORS_HARDWARE_MODULE_ID,
+            (hw_module_t const**)&mSensorModule);
+
+    ALOGE_IF(err, "couldn't load %s module (%s)",
+            SENSORS_HARDWARE_MODULE_ID, strerror(-err));
+
+    if (mSensorModule) {
+        err = sensors_open(&mSensorModule->common, &mSensorDevice);
+
+        ALOGE_IF(err, "couldn't open device for module %s (%s)",
+                SENSORS_HARDWARE_MODULE_ID, strerror(-err));
+
+        if (mSensorDevice) {
+            sensor_t const* list;
+            ssize_t count = mSensorModule->get_sensors_list(mSensorModule, &list);
+            mActivationCount.setCapacity(count);
+            Info model;
+            for (size_t i=0 ; i<size_t(count) ; i++) {
+                mActivationCount.add(list[i].handle, model);
+                mSensorDevice->activate(mSensorDevice, list[i].handle, 0);
+            }
+        }
+    }
+}
+
+void SensorDevice::dump(String8& result, char* buffer, size_t SIZE)
+{
+    if (!mSensorModule) return;
+    sensor_t const* list;
+    ssize_t count = mSensorModule->get_sensors_list(mSensorModule, &list);
+
+    snprintf(buffer, SIZE, "%d h/w sensors:\n", int(count));
+    result.append(buffer);
+
+    Mutex::Autolock _l(mLock);
+    for (size_t i=0 ; i<size_t(count) ; i++) {
+        const Info& info = mActivationCount.valueFor(list[i].handle);
+        snprintf(buffer, SIZE, "handle=0x%08x, active-count=%d, rates(ms)={ ",
+                list[i].handle,
+                info.rates.size());
+        result.append(buffer);
+        for (size_t j=0 ; j<info.rates.size() ; j++) {
+            snprintf(buffer, SIZE, "%4.1f%s",
+                    info.rates.valueAt(j) / 1e6f,
+                    j<info.rates.size()-1 ? ", " : "");
+            result.append(buffer);
+        }
+        snprintf(buffer, SIZE, " }, selected=%4.1f ms\n",  info.delay / 1e6f);
+        result.append(buffer);
+    }
+}
+
+ssize_t SensorDevice::getSensorList(sensor_t const** list) {
+    if (!mSensorModule) return NO_INIT;
+    ssize_t count = mSensorModule->get_sensors_list(mSensorModule, list);
+    return count;
+}
+
+status_t SensorDevice::initCheck() const {
+    return mSensorDevice && mSensorModule ? NO_ERROR : NO_INIT;
+}
+
+ssize_t SensorDevice::poll(sensors_event_t* buffer, size_t count) {
+    if (!mSensorDevice) return NO_INIT;
+    ssize_t c;
+    do {
+        c = mSensorDevice->poll(mSensorDevice, buffer, count);
+    } while (c == -EINTR);
+    return c;
+}
+
+status_t SensorDevice::activate(void* ident, int handle, int enabled)
+{
+    if (!mSensorDevice) return NO_INIT;
+    status_t err(NO_ERROR);
+    bool actuateHardware = false;
+
+    Info& info( mActivationCount.editValueFor(handle) );
+
+
+    ALOGD_IF(DEBUG_CONNECTIONS,
+            "SensorDevice::activate: ident=%p, handle=0x%08x, enabled=%d, count=%d",
+            ident, handle, enabled, info.rates.size());
+
+    if (enabled) {
+        Mutex::Autolock _l(mLock);
+        ALOGD_IF(DEBUG_CONNECTIONS, "... index=%ld",
+                info.rates.indexOfKey(ident));
+
+        if (info.rates.indexOfKey(ident) < 0) {
+            info.rates.add(ident, DEFAULT_EVENTS_PERIOD);
+            if (info.rates.size() == 1) {
+                actuateHardware = true;
+            }
+        } else {
+            // sensor was already activated for this ident
+        }
+    } else {
+        Mutex::Autolock _l(mLock);
+        ALOGD_IF(DEBUG_CONNECTIONS, "... index=%ld",
+                info.rates.indexOfKey(ident));
+
+        ssize_t idx = info.rates.removeItem(ident);
+        if (idx >= 0) {
+            if (info.rates.size() == 0) {
+                actuateHardware = true;
+            }
+        } else {
+            // sensor wasn't enabled for this ident
+        }
+    }
+
+    if (actuateHardware) {
+        ALOGD_IF(DEBUG_CONNECTIONS, "\t>>> actuating h/w");
+
+        err = mSensorDevice->activate(mSensorDevice, handle, enabled);
+        if (enabled) {
+            ALOGE_IF(err, "Error activating sensor %d (%s)", handle, strerror(-err));
+            if (err == 0) {
+                BatteryService::getInstance().enableSensor(handle);
+            }
+        } else {
+            if (err == 0) {
+                BatteryService::getInstance().disableSensor(handle);
+            }
+        }
+    }
+
+    { // scope for the lock
+        Mutex::Autolock _l(mLock);
+        nsecs_t ns = info.selectDelay();
+        mSensorDevice->setDelay(mSensorDevice, handle, ns);
+    }
+
+    return err;
+}
+
+status_t SensorDevice::setDelay(void* ident, int handle, int64_t ns)
+{
+    if (!mSensorDevice) return NO_INIT;
+    Mutex::Autolock _l(mLock);
+    Info& info( mActivationCount.editValueFor(handle) );
+    status_t err = info.setDelayForIdent(ident, ns);
+    if (err < 0) return err;
+    ns = info.selectDelay();
+    return mSensorDevice->setDelay(mSensorDevice, handle, ns);
+}
+
+// ---------------------------------------------------------------------------
+
+status_t SensorDevice::Info::setDelayForIdent(void* ident, int64_t ns)
+{
+    ssize_t index = rates.indexOfKey(ident);
+    if (index < 0) {
+        ALOGE("Info::setDelayForIdent(ident=%p, ns=%lld) failed (%s)",
+                ident, ns, strerror(-index));
+        return BAD_INDEX;
+    }
+    rates.editValueAt(index) = ns;
+    return NO_ERROR;
+}
+
+nsecs_t SensorDevice::Info::selectDelay()
+{
+    nsecs_t ns = rates.valueAt(0);
+    for (size_t i=1 ; i<rates.size() ; i++) {
+        nsecs_t cur = rates.valueAt(i);
+        if (cur < ns) {
+            ns = cur;
+        }
+    }
+    delay = ns;
+    return ns;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
diff --git a/services/sensorservice/SensorDevice.h b/services/sensorservice/SensorDevice.h
new file mode 100644
index 0000000..728b6cb
--- /dev/null
+++ b/services/sensorservice/SensorDevice.h
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_SENSOR_DEVICE_H
+#define ANDROID_SENSOR_DEVICE_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <utils/KeyedVector.h>
+#include <utils/Singleton.h>
+#include <utils/String8.h>
+
+#include <gui/Sensor.h>
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+static const nsecs_t DEFAULT_EVENTS_PERIOD = 200000000; //    5 Hz
+
+class SensorDevice : public Singleton<SensorDevice> {
+    friend class Singleton<SensorDevice>;
+    struct sensors_poll_device_t* mSensorDevice;
+    struct sensors_module_t* mSensorModule;
+    mutable Mutex mLock; // protect mActivationCount[].rates
+    // fixed-size array after construction
+    struct Info {
+        Info() : delay(0) { }
+        KeyedVector<void*, nsecs_t> rates;
+        nsecs_t delay;
+        status_t setDelayForIdent(void* ident, int64_t ns);
+        nsecs_t selectDelay();
+    };
+    DefaultKeyedVector<int, Info> mActivationCount;
+
+    SensorDevice();
+public:
+    ssize_t getSensorList(sensor_t const** list);
+    status_t initCheck() const;
+    ssize_t poll(sensors_event_t* buffer, size_t count);
+    status_t activate(void* ident, int handle, int enabled);
+    status_t setDelay(void* ident, int handle, int64_t ns);
+    void dump(String8& result, char* buffer, size_t SIZE);
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_SENSOR_DEVICE_H
diff --git a/services/sensorservice/SensorFusion.cpp b/services/sensorservice/SensorFusion.cpp
new file mode 100644
index 0000000..d23906d
--- /dev/null
+++ b/services/sensorservice/SensorFusion.cpp
@@ -0,0 +1,148 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "SensorDevice.h"
+#include "SensorFusion.h"
+#include "SensorService.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+ANDROID_SINGLETON_STATIC_INSTANCE(SensorFusion)
+
+SensorFusion::SensorFusion()
+    : mSensorDevice(SensorDevice::getInstance()),
+      mEnabled(false), mGyroTime(0)
+{
+    sensor_t const* list;
+    ssize_t count = mSensorDevice.getSensorList(&list);
+    if (count > 0) {
+        for (size_t i=0 ; i<size_t(count) ; i++) {
+            if (list[i].type == SENSOR_TYPE_ACCELEROMETER) {
+                mAcc = Sensor(list + i);
+            }
+            if (list[i].type == SENSOR_TYPE_MAGNETIC_FIELD) {
+                mMag = Sensor(list + i);
+            }
+            if (list[i].type == SENSOR_TYPE_GYROSCOPE) {
+                mGyro = Sensor(list + i);
+                // 200 Hz for gyro events is a good compromise between precision
+                // and power/cpu usage.
+                mGyroRate = 200;
+                mTargetDelayNs = 1000000000LL/mGyroRate;
+            }
+        }
+        mFusion.init();
+    }
+}
+
+void SensorFusion::process(const sensors_event_t& event) {
+    if (event.type == SENSOR_TYPE_GYROSCOPE) {
+        if (mGyroTime != 0) {
+            const float dT = (event.timestamp - mGyroTime) / 1000000000.0f;
+            const float freq = 1 / dT;
+            if (freq >= 100 && freq<1000) { // filter values obviously wrong
+                const float alpha = 1 / (1 + dT); // 1s time-constant
+                mGyroRate = freq + (mGyroRate - freq)*alpha;
+            }
+        }
+        mGyroTime = event.timestamp;
+        mFusion.handleGyro(vec3_t(event.data), 1.0f/mGyroRate);
+    } else if (event.type == SENSOR_TYPE_MAGNETIC_FIELD) {
+        const vec3_t mag(event.data);
+        mFusion.handleMag(mag);
+    } else if (event.type == SENSOR_TYPE_ACCELEROMETER) {
+        const vec3_t acc(event.data);
+        mFusion.handleAcc(acc);
+        mAttitude = mFusion.getAttitude();
+    }
+}
+
+template <typename T> inline T min(T a, T b) { return a<b ? a : b; }
+template <typename T> inline T max(T a, T b) { return a>b ? a : b; }
+
+status_t SensorFusion::activate(void* ident, bool enabled) {
+
+    ALOGD_IF(DEBUG_CONNECTIONS,
+            "SensorFusion::activate(ident=%p, enabled=%d)",
+            ident, enabled);
+
+    const ssize_t idx = mClients.indexOf(ident);
+    if (enabled) {
+        if (idx < 0) {
+            mClients.add(ident);
+        }
+    } else {
+        if (idx >= 0) {
+            mClients.removeItemsAt(idx);
+        }
+    }
+
+    mSensorDevice.activate(ident, mAcc.getHandle(), enabled);
+    mSensorDevice.activate(ident, mMag.getHandle(), enabled);
+    mSensorDevice.activate(ident, mGyro.getHandle(), enabled);
+
+    const bool newState = mClients.size() != 0;
+    if (newState != mEnabled) {
+        mEnabled = newState;
+        if (newState) {
+            mFusion.init();
+            mGyroTime = 0;
+        }
+    }
+    return NO_ERROR;
+}
+
+status_t SensorFusion::setDelay(void* ident, int64_t ns) {
+    mSensorDevice.setDelay(ident, mAcc.getHandle(), ns);
+    mSensorDevice.setDelay(ident, mMag.getHandle(), ms2ns(20));
+    mSensorDevice.setDelay(ident, mGyro.getHandle(), mTargetDelayNs);
+    return NO_ERROR;
+}
+
+
+float SensorFusion::getPowerUsage() const {
+    float power =   mAcc.getPowerUsage() +
+                    mMag.getPowerUsage() +
+                    mGyro.getPowerUsage();
+    return power;
+}
+
+int32_t SensorFusion::getMinDelay() const {
+    return mAcc.getMinDelay();
+}
+
+void SensorFusion::dump(String8& result, char* buffer, size_t SIZE) {
+    const Fusion& fusion(mFusion);
+    snprintf(buffer, SIZE, "9-axis fusion %s (%d clients), gyro-rate=%7.2fHz, "
+            "q=< %g, %g, %g, %g > (%g), "
+            "b=< %g, %g, %g >\n",
+            mEnabled ? "enabled" : "disabled",
+            mClients.size(),
+            mGyroRate,
+            fusion.getAttitude().x,
+            fusion.getAttitude().y,
+            fusion.getAttitude().z,
+            fusion.getAttitude().w,
+            length(fusion.getAttitude()),
+            fusion.getBias().x,
+            fusion.getBias().y,
+            fusion.getBias().z);
+    result.append(buffer);
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
diff --git a/services/sensorservice/SensorFusion.h b/services/sensorservice/SensorFusion.h
new file mode 100644
index 0000000..4c99bcb
--- /dev/null
+++ b/services/sensorservice/SensorFusion.h
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_SENSOR_FUSION_H
+#define ANDROID_SENSOR_FUSION_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <utils/SortedVector.h>
+#include <utils/Singleton.h>
+#include <utils/String8.h>
+
+#include <gui/Sensor.h>
+
+#include "Fusion.h"
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+class SensorDevice;
+
+class SensorFusion : public Singleton<SensorFusion> {
+    friend class Singleton<SensorFusion>;
+
+    SensorDevice& mSensorDevice;
+    Sensor mAcc;
+    Sensor mMag;
+    Sensor mGyro;
+    Fusion mFusion;
+    bool mEnabled;
+    float mGyroRate;
+    nsecs_t mTargetDelayNs;
+    nsecs_t mGyroTime;
+    vec4_t mAttitude;
+    SortedVector<void*> mClients;
+
+    SensorFusion();
+
+public:
+    void process(const sensors_event_t& event);
+
+    bool isEnabled() const { return mEnabled; }
+    bool hasEstimate() const { return mFusion.hasEstimate(); }
+    mat33_t getRotationMatrix() const { return mFusion.getRotationMatrix(); }
+    vec4_t getAttitude() const { return mAttitude; }
+    vec3_t getGyroBias() const { return mFusion.getBias(); }
+    float getEstimatedRate() const { return mGyroRate; }
+
+    status_t activate(void* ident, bool enabled);
+    status_t setDelay(void* ident, int64_t ns);
+
+    float getPowerUsage() const;
+    int32_t getMinDelay() const;
+
+    void dump(String8& result, char* buffer, size_t SIZE);
+};
+
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_SENSOR_FUSION_H
diff --git a/services/sensorservice/SensorInterface.cpp b/services/sensorservice/SensorInterface.cpp
new file mode 100644
index 0000000..468aa61
--- /dev/null
+++ b/services/sensorservice/SensorInterface.cpp
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <cutils/log.h>
+
+#include "SensorInterface.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+SensorInterface::~SensorInterface()
+{
+}
+
+// ---------------------------------------------------------------------------
+
+HardwareSensor::HardwareSensor(const sensor_t& sensor)
+    : mSensorDevice(SensorDevice::getInstance()),
+      mSensor(&sensor)
+{
+    ALOGI("%s", sensor.name);
+}
+
+HardwareSensor::~HardwareSensor() {
+}
+
+bool HardwareSensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event) {
+    *outEvent = event;
+    return true;
+}
+
+status_t HardwareSensor::activate(void* ident, bool enabled) {
+    return mSensorDevice.activate(ident, mSensor.getHandle(), enabled);
+}
+
+status_t HardwareSensor::setDelay(void* ident, int handle, int64_t ns) {
+    return mSensorDevice.setDelay(ident, handle, ns);
+}
+
+Sensor HardwareSensor::getSensor() const {
+    return mSensor;
+}
+
+
+// ---------------------------------------------------------------------------
+}; // namespace android
diff --git a/services/sensorservice/SensorInterface.h b/services/sensorservice/SensorInterface.h
new file mode 100644
index 0000000..fb357d7
--- /dev/null
+++ b/services/sensorservice/SensorInterface.h
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_SENSOR_INTERFACE_H
+#define ANDROID_SENSOR_INTERFACE_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <gui/Sensor.h>
+
+#include "SensorDevice.h"
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+class SensorInterface {
+public:
+    virtual ~SensorInterface();
+
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event) = 0;
+
+    virtual status_t activate(void* ident, bool enabled) = 0;
+    virtual status_t setDelay(void* ident, int handle, int64_t ns) = 0;
+    virtual Sensor getSensor() const = 0;
+    virtual bool isVirtual() const = 0;
+};
+
+// ---------------------------------------------------------------------------
+
+class HardwareSensor : public SensorInterface
+{
+    SensorDevice& mSensorDevice;
+    Sensor mSensor;
+
+public:
+    HardwareSensor(const sensor_t& sensor);
+
+    virtual ~HardwareSensor();
+
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return false; }
+};
+
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_SENSOR_INTERFACE_H
diff --git a/services/sensorservice/SensorService.cpp b/services/sensorservice/SensorService.cpp
new file mode 100644
index 0000000..9e5e84b
--- /dev/null
+++ b/services/sensorservice/SensorService.cpp
@@ -0,0 +1,637 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <cutils/properties.h>
+
+#include <utils/SortedVector.h>
+#include <utils/KeyedVector.h>
+#include <utils/threads.h>
+#include <utils/Atomic.h>
+#include <utils/Errors.h>
+#include <utils/RefBase.h>
+#include <utils/Singleton.h>
+#include <utils/String16.h>
+
+#include <binder/BinderService.h>
+#include <binder/IServiceManager.h>
+#include <binder/PermissionCache.h>
+
+#include <gui/ISensorServer.h>
+#include <gui/ISensorEventConnection.h>
+#include <gui/SensorEventQueue.h>
+
+#include <hardware/sensors.h>
+
+#include "CorrectedGyroSensor.h"
+#include "GravitySensor.h"
+#include "LinearAccelerationSensor.h"
+#include "OrientationSensor.h"
+#include "RotationVectorSensor.h"
+#include "SensorFusion.h"
+#include "SensorService.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+/*
+ * Notes:
+ *
+ * - what about a gyro-corrected magnetic-field sensor?
+ * - run mag sensor from time to time to force calibration
+ * - gravity sensor length is wrong (=> drift in linear-acc sensor)
+ *
+ */
+
+SensorService::SensorService()
+    : mInitCheck(NO_INIT)
+{
+}
+
+void SensorService::onFirstRef()
+{
+    ALOGD("nuSensorService starting...");
+
+    SensorDevice& dev(SensorDevice::getInstance());
+
+    if (dev.initCheck() == NO_ERROR) {
+        sensor_t const* list;
+        ssize_t count = dev.getSensorList(&list);
+        if (count > 0) {
+            ssize_t orientationIndex = -1;
+            bool hasGyro = false;
+            uint32_t virtualSensorsNeeds =
+                    (1<<SENSOR_TYPE_GRAVITY) |
+                    (1<<SENSOR_TYPE_LINEAR_ACCELERATION) |
+                    (1<<SENSOR_TYPE_ROTATION_VECTOR);
+
+            mLastEventSeen.setCapacity(count);
+            for (ssize_t i=0 ; i<count ; i++) {
+                registerSensor( new HardwareSensor(list[i]) );
+                switch (list[i].type) {
+                    case SENSOR_TYPE_ORIENTATION:
+                        orientationIndex = i;
+                        break;
+                    case SENSOR_TYPE_GYROSCOPE:
+                        hasGyro = true;
+                        break;
+                    case SENSOR_TYPE_GRAVITY:
+                    case SENSOR_TYPE_LINEAR_ACCELERATION:
+                    case SENSOR_TYPE_ROTATION_VECTOR:
+                        virtualSensorsNeeds &= ~(1<<list[i].type);
+                        break;
+                }
+            }
+
+            // it's safe to instantiate the SensorFusion object here
+            // (it wants to be instantiated after h/w sensors have been
+            // registered)
+            const SensorFusion& fusion(SensorFusion::getInstance());
+
+            if (hasGyro) {
+                // Always instantiate Android's virtual sensors. Since they are
+                // instantiated behind sensors from the HAL, they won't
+                // interfere with applications, unless they looks specifically
+                // for them (by name).
+
+                registerVirtualSensor( new RotationVectorSensor() );
+                registerVirtualSensor( new GravitySensor(list, count) );
+                registerVirtualSensor( new LinearAccelerationSensor(list, count) );
+
+                // these are optional
+                registerVirtualSensor( new OrientationSensor() );
+                registerVirtualSensor( new CorrectedGyroSensor(list, count) );
+
+                // virtual debugging sensors...
+                char value[PROPERTY_VALUE_MAX];
+                property_get("debug.sensors", value, "0");
+                if (atoi(value)) {
+                    registerVirtualSensor( new GyroDriftSensor() );
+                }
+            }
+
+            // build the sensor list returned to users
+            mUserSensorList = mSensorList;
+            if (hasGyro &&
+                    (virtualSensorsNeeds & (1<<SENSOR_TYPE_ROTATION_VECTOR))) {
+                // if we have the fancy sensor fusion, and it's not provided by the
+                // HAL, use our own (fused) orientation sensor by removing the
+                // HAL supplied one form the user list.
+                if (orientationIndex >= 0) {
+                    mUserSensorList.removeItemsAt(orientationIndex);
+                }
+            }
+
+            run("SensorService", PRIORITY_URGENT_DISPLAY);
+            mInitCheck = NO_ERROR;
+        }
+    }
+}
+
+void SensorService::registerSensor(SensorInterface* s)
+{
+    sensors_event_t event;
+    memset(&event, 0, sizeof(event));
+
+    const Sensor sensor(s->getSensor());
+    // add to the sensor list (returned to clients)
+    mSensorList.add(sensor);
+    // add to our handle->SensorInterface mapping
+    mSensorMap.add(sensor.getHandle(), s);
+    // create an entry in the mLastEventSeen array
+    mLastEventSeen.add(sensor.getHandle(), event);
+}
+
+void SensorService::registerVirtualSensor(SensorInterface* s)
+{
+    registerSensor(s);
+    mVirtualSensorList.add( s );
+}
+
+SensorService::~SensorService()
+{
+    for (size_t i=0 ; i<mSensorMap.size() ; i++)
+        delete mSensorMap.valueAt(i);
+}
+
+static const String16 sDump("android.permission.DUMP");
+
+status_t SensorService::dump(int fd, const Vector<String16>& args)
+{
+    const size_t SIZE = 1024;
+    char buffer[SIZE];
+    String8 result;
+    if (!PermissionCache::checkCallingPermission(sDump)) {
+        snprintf(buffer, SIZE, "Permission Denial: "
+                "can't dump SurfaceFlinger from pid=%d, uid=%d\n",
+                IPCThreadState::self()->getCallingPid(),
+                IPCThreadState::self()->getCallingUid());
+        result.append(buffer);
+    } else {
+        Mutex::Autolock _l(mLock);
+        snprintf(buffer, SIZE, "Sensor List:\n");
+        result.append(buffer);
+        for (size_t i=0 ; i<mSensorList.size() ; i++) {
+            const Sensor& s(mSensorList[i]);
+            const sensors_event_t& e(mLastEventSeen.valueFor(s.getHandle()));
+            snprintf(buffer, SIZE,
+                    "%-48s| %-32s | 0x%08x | maxRate=%7.2fHz | "
+                    "last=<%5.1f,%5.1f,%5.1f>\n",
+                    s.getName().string(),
+                    s.getVendor().string(),
+                    s.getHandle(),
+                    s.getMinDelay() ? (1000000.0f / s.getMinDelay()) : 0.0f,
+                    e.data[0], e.data[1], e.data[2]);
+            result.append(buffer);
+        }
+        SensorFusion::getInstance().dump(result, buffer, SIZE);
+        SensorDevice::getInstance().dump(result, buffer, SIZE);
+
+        snprintf(buffer, SIZE, "%d active connections\n",
+                mActiveConnections.size());
+        result.append(buffer);
+        snprintf(buffer, SIZE, "Active sensors:\n");
+        result.append(buffer);
+        for (size_t i=0 ; i<mActiveSensors.size() ; i++) {
+            int handle = mActiveSensors.keyAt(i);
+            snprintf(buffer, SIZE, "%s (handle=0x%08x, connections=%d)\n",
+                    getSensorName(handle).string(),
+                    handle,
+                    mActiveSensors.valueAt(i)->getNumConnections());
+            result.append(buffer);
+        }
+    }
+    write(fd, result.string(), result.size());
+    return NO_ERROR;
+}
+
+bool SensorService::threadLoop()
+{
+    ALOGD("nuSensorService thread starting...");
+
+    const size_t numEventMax = 16;
+    const size_t minBufferSize = numEventMax + numEventMax * mVirtualSensorList.size();
+    sensors_event_t buffer[minBufferSize];
+    sensors_event_t scratch[minBufferSize];
+    SensorDevice& device(SensorDevice::getInstance());
+    const size_t vcount = mVirtualSensorList.size();
+
+    ssize_t count;
+    do {
+        count = device.poll(buffer, numEventMax);
+        if (count<0) {
+            ALOGE("sensor poll failed (%s)", strerror(-count));
+            break;
+        }
+
+        recordLastValue(buffer, count);
+
+        // handle virtual sensors
+        if (count && vcount) {
+            sensors_event_t const * const event = buffer;
+            const DefaultKeyedVector<int, SensorInterface*> virtualSensors(
+                    getActiveVirtualSensors());
+            const size_t activeVirtualSensorCount = virtualSensors.size();
+            if (activeVirtualSensorCount) {
+                size_t k = 0;
+                SensorFusion& fusion(SensorFusion::getInstance());
+                if (fusion.isEnabled()) {
+                    for (size_t i=0 ; i<size_t(count) ; i++) {
+                        fusion.process(event[i]);
+                    }
+                }
+                for (size_t i=0 ; i<size_t(count) && k<minBufferSize ; i++) {
+                    for (size_t j=0 ; j<activeVirtualSensorCount ; j++) {
+                        if (count + k >= minBufferSize) {
+                            ALOGE("buffer too small to hold all events: "
+                                    "count=%u, k=%u, size=%u",
+                                    count, k, minBufferSize);
+                            break;
+                        }
+                        sensors_event_t out;
+                        SensorInterface* si = virtualSensors.valueAt(j);
+                        if (si->process(&out, event[i])) {
+                            buffer[count + k] = out;
+                            k++;
+                        }
+                    }
+                }
+                if (k) {
+                    // record the last synthesized values
+                    recordLastValue(&buffer[count], k);
+                    count += k;
+                    // sort the buffer by time-stamps
+                    sortEventBuffer(buffer, count);
+                }
+            }
+        }
+
+        // send our events to clients...
+        const SortedVector< wp<SensorEventConnection> > activeConnections(
+                getActiveConnections());
+        size_t numConnections = activeConnections.size();
+        for (size_t i=0 ; i<numConnections ; i++) {
+            sp<SensorEventConnection> connection(
+                    activeConnections[i].promote());
+            if (connection != 0) {
+                connection->sendEvents(buffer, count, scratch);
+            }
+        }
+    } while (count >= 0 || Thread::exitPending());
+
+    ALOGW("Exiting SensorService::threadLoop => aborting...");
+    abort();
+    return false;
+}
+
+void SensorService::recordLastValue(
+        sensors_event_t const * buffer, size_t count)
+{
+    Mutex::Autolock _l(mLock);
+
+    // record the last event for each sensor
+    int32_t prev = buffer[0].sensor;
+    for (size_t i=1 ; i<count ; i++) {
+        // record the last event of each sensor type in this buffer
+        int32_t curr = buffer[i].sensor;
+        if (curr != prev) {
+            mLastEventSeen.editValueFor(prev) = buffer[i-1];
+            prev = curr;
+        }
+    }
+    mLastEventSeen.editValueFor(prev) = buffer[count-1];
+}
+
+void SensorService::sortEventBuffer(sensors_event_t* buffer, size_t count)
+{
+    struct compar {
+        static int cmp(void const* lhs, void const* rhs) {
+            sensors_event_t const* l = static_cast<sensors_event_t const*>(lhs);
+            sensors_event_t const* r = static_cast<sensors_event_t const*>(rhs);
+            return l->timestamp - r->timestamp;
+        }
+    };
+    qsort(buffer, count, sizeof(sensors_event_t), compar::cmp);
+}
+
+SortedVector< wp<SensorService::SensorEventConnection> >
+SensorService::getActiveConnections() const
+{
+    Mutex::Autolock _l(mLock);
+    return mActiveConnections;
+}
+
+DefaultKeyedVector<int, SensorInterface*>
+SensorService::getActiveVirtualSensors() const
+{
+    Mutex::Autolock _l(mLock);
+    return mActiveVirtualSensors;
+}
+
+String8 SensorService::getSensorName(int handle) const {
+    size_t count = mUserSensorList.size();
+    for (size_t i=0 ; i<count ; i++) {
+        const Sensor& sensor(mUserSensorList[i]);
+        if (sensor.getHandle() == handle) {
+            return sensor.getName();
+        }
+    }
+    String8 result("unknown");
+    return result;
+}
+
+Vector<Sensor> SensorService::getSensorList()
+{
+    return mUserSensorList;
+}
+
+sp<ISensorEventConnection> SensorService::createSensorEventConnection()
+{
+    sp<SensorEventConnection> result(new SensorEventConnection(this));
+    return result;
+}
+
+void SensorService::cleanupConnection(SensorEventConnection* c)
+{
+    Mutex::Autolock _l(mLock);
+    const wp<SensorEventConnection> connection(c);
+    size_t size = mActiveSensors.size();
+    ALOGD_IF(DEBUG_CONNECTIONS, "%d active sensors", size);
+    for (size_t i=0 ; i<size ; ) {
+        int handle = mActiveSensors.keyAt(i);
+        if (c->hasSensor(handle)) {
+            ALOGD_IF(DEBUG_CONNECTIONS, "%i: disabling handle=0x%08x", i, handle);
+            SensorInterface* sensor = mSensorMap.valueFor( handle );
+            ALOGE_IF(!sensor, "mSensorMap[handle=0x%08x] is null!", handle);
+            if (sensor) {
+                sensor->activate(c, false);
+            }
+        }
+        SensorRecord* rec = mActiveSensors.valueAt(i);
+        ALOGE_IF(!rec, "mActiveSensors[%d] is null (handle=0x%08x)!", i, handle);
+        ALOGD_IF(DEBUG_CONNECTIONS,
+                "removing connection %p for sensor[%d].handle=0x%08x",
+                c, i, handle);
+
+        if (rec && rec->removeConnection(connection)) {
+            ALOGD_IF(DEBUG_CONNECTIONS, "... and it was the last connection");
+            mActiveSensors.removeItemsAt(i, 1);
+            mActiveVirtualSensors.removeItem(handle);
+            delete rec;
+            size--;
+        } else {
+            i++;
+        }
+    }
+    mActiveConnections.remove(connection);
+}
+
+status_t SensorService::enable(const sp<SensorEventConnection>& connection,
+        int handle)
+{
+    if (mInitCheck != NO_ERROR)
+        return mInitCheck;
+
+    Mutex::Autolock _l(mLock);
+    SensorInterface* sensor = mSensorMap.valueFor(handle);
+    status_t err = sensor ? sensor->activate(connection.get(), true) : status_t(BAD_VALUE);
+    if (err == NO_ERROR) {
+        SensorRecord* rec = mActiveSensors.valueFor(handle);
+        if (rec == 0) {
+            rec = new SensorRecord(connection);
+            mActiveSensors.add(handle, rec);
+            if (sensor->isVirtual()) {
+                mActiveVirtualSensors.add(handle, sensor);
+            }
+        } else {
+            if (rec->addConnection(connection)) {
+                // this sensor is already activated, but we are adding a
+                // connection that uses it. Immediately send down the last
+                // known value of the requested sensor if it's not a
+                // "continuous" sensor.
+                if (sensor->getSensor().getMinDelay() == 0) {
+                    sensors_event_t scratch;
+                    sensors_event_t& event(mLastEventSeen.editValueFor(handle));
+                    if (event.version == sizeof(sensors_event_t)) {
+                        connection->sendEvents(&event, 1);
+                    }
+                }
+            }
+        }
+        if (err == NO_ERROR) {
+            // connection now active
+            if (connection->addSensor(handle)) {
+                // the sensor was added (which means it wasn't already there)
+                // so, see if this connection becomes active
+                if (mActiveConnections.indexOf(connection) < 0) {
+                    mActiveConnections.add(connection);
+                }
+            }
+        }
+    }
+    return err;
+}
+
+status_t SensorService::disable(const sp<SensorEventConnection>& connection,
+        int handle)
+{
+    if (mInitCheck != NO_ERROR)
+        return mInitCheck;
+
+    status_t err = NO_ERROR;
+    Mutex::Autolock _l(mLock);
+    SensorRecord* rec = mActiveSensors.valueFor(handle);
+    if (rec) {
+        // see if this connection becomes inactive
+        connection->removeSensor(handle);
+        if (connection->hasAnySensor() == false) {
+            mActiveConnections.remove(connection);
+        }
+        // see if this sensor becomes inactive
+        if (rec->removeConnection(connection)) {
+            mActiveSensors.removeItem(handle);
+            mActiveVirtualSensors.removeItem(handle);
+            delete rec;
+        }
+        SensorInterface* sensor = mSensorMap.valueFor(handle);
+        err = sensor ? sensor->activate(connection.get(), false) : status_t(BAD_VALUE);
+    }
+    return err;
+}
+
+status_t SensorService::setEventRate(const sp<SensorEventConnection>& connection,
+        int handle, nsecs_t ns)
+{
+    if (mInitCheck != NO_ERROR)
+        return mInitCheck;
+
+    SensorInterface* sensor = mSensorMap.valueFor(handle);
+    if (!sensor)
+        return BAD_VALUE;
+
+    if (ns < 0)
+        return BAD_VALUE;
+
+    nsecs_t minDelayNs = sensor->getSensor().getMinDelayNs();
+    if (ns < minDelayNs) {
+        ns = minDelayNs;
+    }
+
+    if (ns < MINIMUM_EVENTS_PERIOD)
+        ns = MINIMUM_EVENTS_PERIOD;
+
+    return sensor->setDelay(connection.get(), handle, ns);
+}
+
+// ---------------------------------------------------------------------------
+
+SensorService::SensorRecord::SensorRecord(
+        const sp<SensorEventConnection>& connection)
+{
+    mConnections.add(connection);
+}
+
+bool SensorService::SensorRecord::addConnection(
+        const sp<SensorEventConnection>& connection)
+{
+    if (mConnections.indexOf(connection) < 0) {
+        mConnections.add(connection);
+        return true;
+    }
+    return false;
+}
+
+bool SensorService::SensorRecord::removeConnection(
+        const wp<SensorEventConnection>& connection)
+{
+    ssize_t index = mConnections.indexOf(connection);
+    if (index >= 0) {
+        mConnections.removeItemsAt(index, 1);
+    }
+    return mConnections.size() ? false : true;
+}
+
+// ---------------------------------------------------------------------------
+
+SensorService::SensorEventConnection::SensorEventConnection(
+        const sp<SensorService>& service)
+    : mService(service), mChannel(new BitTube())
+{
+}
+
+SensorService::SensorEventConnection::~SensorEventConnection()
+{
+    ALOGD_IF(DEBUG_CONNECTIONS, "~SensorEventConnection(%p)", this);
+    mService->cleanupConnection(this);
+}
+
+void SensorService::SensorEventConnection::onFirstRef()
+{
+}
+
+bool SensorService::SensorEventConnection::addSensor(int32_t handle) {
+    Mutex::Autolock _l(mConnectionLock);
+    if (mSensorInfo.indexOf(handle) <= 0) {
+        mSensorInfo.add(handle);
+        return true;
+    }
+    return false;
+}
+
+bool SensorService::SensorEventConnection::removeSensor(int32_t handle) {
+    Mutex::Autolock _l(mConnectionLock);
+    if (mSensorInfo.remove(handle) >= 0) {
+        return true;
+    }
+    return false;
+}
+
+bool SensorService::SensorEventConnection::hasSensor(int32_t handle) const {
+    Mutex::Autolock _l(mConnectionLock);
+    return mSensorInfo.indexOf(handle) >= 0;
+}
+
+bool SensorService::SensorEventConnection::hasAnySensor() const {
+    Mutex::Autolock _l(mConnectionLock);
+    return mSensorInfo.size() ? true : false;
+}
+
+status_t SensorService::SensorEventConnection::sendEvents(
+        sensors_event_t const* buffer, size_t numEvents,
+        sensors_event_t* scratch)
+{
+    // filter out events not for this connection
+    size_t count = 0;
+    if (scratch) {
+        Mutex::Autolock _l(mConnectionLock);
+        size_t i=0;
+        while (i<numEvents) {
+            const int32_t curr = buffer[i].sensor;
+            if (mSensorInfo.indexOf(curr) >= 0) {
+                do {
+                    scratch[count++] = buffer[i++];
+                } while ((i<numEvents) && (buffer[i].sensor == curr));
+            } else {
+                i++;
+            }
+        }
+    } else {
+        scratch = const_cast<sensors_event_t *>(buffer);
+        count = numEvents;
+    }
+
+    // NOTE: ASensorEvent and sensors_event_t are the same type
+    ssize_t size = SensorEventQueue::write(mChannel,
+            reinterpret_cast<ASensorEvent const*>(scratch), count);
+    if (size == -EAGAIN) {
+        // the destination doesn't accept events anymore, it's probably
+        // full. For now, we just drop the events on the floor.
+        //ALOGW("dropping %d events on the floor", count);
+        return size;
+    }
+
+    return size < 0 ? status_t(size) : status_t(NO_ERROR);
+}
+
+sp<BitTube> SensorService::SensorEventConnection::getSensorChannel() const
+{
+    return mChannel;
+}
+
+status_t SensorService::SensorEventConnection::enableDisable(
+        int handle, bool enabled)
+{
+    status_t err;
+    if (enabled) {
+        err = mService->enable(this, handle);
+    } else {
+        err = mService->disable(this, handle);
+    }
+    return err;
+}
+
+status_t SensorService::SensorEventConnection::setEventRate(
+        int handle, nsecs_t ns)
+{
+    return mService->setEventRate(this, handle, ns);
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
diff --git a/services/sensorservice/SensorService.h b/services/sensorservice/SensorService.h
new file mode 100644
index 0000000..e357f96
--- /dev/null
+++ b/services/sensorservice/SensorService.h
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_SENSOR_SERVICE_H
+#define ANDROID_SENSOR_SERVICE_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <utils/Vector.h>
+#include <utils/SortedVector.h>
+#include <utils/KeyedVector.h>
+#include <utils/threads.h>
+#include <utils/RefBase.h>
+
+#include <binder/BinderService.h>
+
+#include <gui/Sensor.h>
+#include <gui/BitTube.h>
+#include <gui/ISensorServer.h>
+#include <gui/ISensorEventConnection.h>
+
+#include "SensorInterface.h"
+
+// ---------------------------------------------------------------------------
+
+#define DEBUG_CONNECTIONS   false
+
+struct sensors_poll_device_t;
+struct sensors_module_t;
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+class SensorService :
+        public BinderService<SensorService>,
+        public BnSensorServer,
+        protected Thread
+{
+   friend class BinderService<SensorService>;
+
+   static const nsecs_t MINIMUM_EVENTS_PERIOD =   1000000; // 1000 Hz
+
+            SensorService();
+    virtual ~SensorService();
+
+    virtual void onFirstRef();
+
+    // Thread interface
+    virtual bool threadLoop();
+
+    // ISensorServer interface
+    virtual Vector<Sensor> getSensorList();
+    virtual sp<ISensorEventConnection> createSensorEventConnection();
+    virtual status_t dump(int fd, const Vector<String16>& args);
+
+
+    class SensorEventConnection : public BnSensorEventConnection {
+        virtual ~SensorEventConnection();
+        virtual void onFirstRef();
+        virtual sp<BitTube> getSensorChannel() const;
+        virtual status_t enableDisable(int handle, bool enabled);
+        virtual status_t setEventRate(int handle, nsecs_t ns);
+
+        sp<SensorService> const mService;
+        sp<BitTube> const mChannel;
+        mutable Mutex mConnectionLock;
+
+        // protected by SensorService::mLock
+        SortedVector<int> mSensorInfo;
+
+    public:
+        SensorEventConnection(const sp<SensorService>& service);
+
+        status_t sendEvents(sensors_event_t const* buffer, size_t count,
+                sensors_event_t* scratch = NULL);
+        bool hasSensor(int32_t handle) const;
+        bool hasAnySensor() const;
+        bool addSensor(int32_t handle);
+        bool removeSensor(int32_t handle);
+    };
+
+    class SensorRecord {
+        SortedVector< wp<SensorEventConnection> > mConnections;
+    public:
+        SensorRecord(const sp<SensorEventConnection>& connection);
+        bool addConnection(const sp<SensorEventConnection>& connection);
+        bool removeConnection(const wp<SensorEventConnection>& connection);
+        size_t getNumConnections() const { return mConnections.size(); }
+    };
+
+    SortedVector< wp<SensorEventConnection> > getActiveConnections() const;
+    DefaultKeyedVector<int, SensorInterface*> getActiveVirtualSensors() const;
+
+    String8 getSensorName(int handle) const;
+    void recordLastValue(sensors_event_t const * buffer, size_t count);
+    static void sortEventBuffer(sensors_event_t* buffer, size_t count);
+    void registerSensor(SensorInterface* sensor);
+    void registerVirtualSensor(SensorInterface* sensor);
+
+    // constants
+    Vector<Sensor> mSensorList;
+    Vector<Sensor> mUserSensorList;
+    DefaultKeyedVector<int, SensorInterface*> mSensorMap;
+    Vector<SensorInterface *> mVirtualSensorList;
+    status_t mInitCheck;
+
+    // protected by mLock
+    mutable Mutex mLock;
+    DefaultKeyedVector<int, SensorRecord*> mActiveSensors;
+    DefaultKeyedVector<int, SensorInterface*> mActiveVirtualSensors;
+    SortedVector< wp<SensorEventConnection> > mActiveConnections;
+
+    // The size of this vector is constant, only the items are mutable
+    KeyedVector<int32_t, sensors_event_t> mLastEventSeen;
+
+public:
+    static char const* getServiceName() { return "sensorservice"; }
+
+    void cleanupConnection(SensorEventConnection* connection);
+    status_t enable(const sp<SensorEventConnection>& connection, int handle);
+    status_t disable(const sp<SensorEventConnection>& connection, int handle);
+    status_t setEventRate(const sp<SensorEventConnection>& connection, int handle, nsecs_t ns);
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_SENSOR_SERVICE_H
diff --git a/services/sensorservice/mat.h b/services/sensorservice/mat.h
new file mode 100644
index 0000000..a76fc91
--- /dev/null
+++ b/services/sensorservice/mat.h
@@ -0,0 +1,393 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_MAT_H
+#define ANDROID_MAT_H
+
+#include "vec.h"
+#include "traits.h"
+
+// -----------------------------------------------------------------------
+
+namespace android {
+
+template <typename TYPE, size_t C, size_t R>
+class mat;
+
+namespace helpers {
+
+template <typename TYPE, size_t C, size_t R>
+mat<TYPE, C, R>& doAssign(
+        mat<TYPE, C, R>& lhs,
+        typename TypeTraits<TYPE>::ParameterType rhs) {
+    for (size_t i=0 ; i<C ; i++)
+        for (size_t j=0 ; j<R ; j++)
+            lhs[i][j] = (i==j) ? rhs : 0;
+    return lhs;
+}
+
+template <typename TYPE, size_t C, size_t R, size_t D>
+mat<TYPE, C, R> PURE doMul(
+        const mat<TYPE, D, R>& lhs,
+        const mat<TYPE, C, D>& rhs)
+{
+    mat<TYPE, C, R> res;
+    for (size_t c=0 ; c<C ; c++) {
+        for (size_t r=0 ; r<R ; r++) {
+            TYPE v(0);
+            for (size_t k=0 ; k<D ; k++) {
+                v += lhs[k][r] * rhs[c][k];
+            }
+            res[c][r] = v;
+        }
+    }
+    return res;
+}
+
+template <typename TYPE, size_t R, size_t D>
+vec<TYPE, R> PURE doMul(
+        const mat<TYPE, D, R>& lhs,
+        const vec<TYPE, D>& rhs)
+{
+    vec<TYPE, R> res;
+    for (size_t r=0 ; r<R ; r++) {
+        TYPE v(0);
+        for (size_t k=0 ; k<D ; k++) {
+            v += lhs[k][r] * rhs[k];
+        }
+        res[r] = v;
+    }
+    return res;
+}
+
+template <typename TYPE, size_t C, size_t R>
+mat<TYPE, C, R> PURE doMul(
+        const vec<TYPE, R>& lhs,
+        const mat<TYPE, C, 1>& rhs)
+{
+    mat<TYPE, C, R> res;
+    for (size_t c=0 ; c<C ; c++) {
+        for (size_t r=0 ; r<R ; r++) {
+            res[c][r] = lhs[r] * rhs[c][0];
+        }
+    }
+    return res;
+}
+
+template <typename TYPE, size_t C, size_t R>
+mat<TYPE, C, R> PURE doMul(
+        const mat<TYPE, C, R>& rhs,
+        typename TypeTraits<TYPE>::ParameterType v)
+{
+    mat<TYPE, C, R> res;
+    for (size_t c=0 ; c<C ; c++) {
+        for (size_t r=0 ; r<R ; r++) {
+            res[c][r] = rhs[c][r] * v;
+        }
+    }
+    return res;
+}
+
+template <typename TYPE, size_t C, size_t R>
+mat<TYPE, C, R> PURE doMul(
+        typename TypeTraits<TYPE>::ParameterType v,
+        const mat<TYPE, C, R>& rhs)
+{
+    mat<TYPE, C, R> res;
+    for (size_t c=0 ; c<C ; c++) {
+        for (size_t r=0 ; r<R ; r++) {
+            res[c][r] = v * rhs[c][r];
+        }
+    }
+    return res;
+}
+
+
+}; // namespace helpers
+
+// -----------------------------------------------------------------------
+
+template <typename TYPE, size_t C, size_t R>
+class mat : public vec< vec<TYPE, R>, C > {
+    typedef typename TypeTraits<TYPE>::ParameterType pTYPE;
+    typedef vec< vec<TYPE, R>, C > base;
+public:
+    // STL-like interface.
+    typedef TYPE value_type;
+    typedef TYPE& reference;
+    typedef TYPE const& const_reference;
+    typedef size_t size_type;
+    size_type size() const { return R*C; }
+    enum { ROWS = R, COLS = C };
+
+
+    // -----------------------------------------------------------------------
+    // default constructors
+
+    mat() { }
+    mat(const mat& rhs)  : base(rhs) { }
+    mat(const base& rhs) : base(rhs) { }
+
+    // -----------------------------------------------------------------------
+    // conversion constructors
+
+    // sets the diagonal to the value, off-diagonal to zero
+    mat(pTYPE rhs) {
+        helpers::doAssign(*this, rhs);
+    }
+
+    // -----------------------------------------------------------------------
+    // Assignment
+
+    mat& operator=(const mat& rhs) {
+        base::operator=(rhs);
+        return *this;
+    }
+
+    mat& operator=(const base& rhs) {
+        base::operator=(rhs);
+        return *this;
+    }
+
+    mat& operator=(pTYPE rhs) {
+        return helpers::doAssign(*this, rhs);
+    }
+
+    // -----------------------------------------------------------------------
+    // non-member function declaration and definition
+
+    friend inline mat PURE operator + (const mat& lhs, const mat& rhs) {
+        return helpers::doAdd(
+                static_cast<const base&>(lhs),
+                static_cast<const base&>(rhs));
+    }
+    friend inline mat PURE operator - (const mat& lhs, const mat& rhs) {
+        return helpers::doSub(
+                static_cast<const base&>(lhs),
+                static_cast<const base&>(rhs));
+    }
+
+    // matrix*matrix
+    template <size_t D>
+    friend mat PURE operator * (
+            const mat<TYPE, D, R>& lhs,
+            const mat<TYPE, C, D>& rhs) {
+        return helpers::doMul(lhs, rhs);
+    }
+
+    // matrix*vector
+    friend vec<TYPE, R> PURE operator * (
+            const mat& lhs, const vec<TYPE, C>& rhs) {
+        return helpers::doMul(lhs, rhs);
+    }
+
+    // vector*matrix
+    friend mat PURE operator * (
+            const vec<TYPE, R>& lhs, const mat<TYPE, C, 1>& rhs) {
+        return helpers::doMul(lhs, rhs);
+    }
+
+    // matrix*scalar
+    friend inline mat PURE operator * (const mat& lhs, pTYPE v) {
+        return helpers::doMul(lhs, v);
+    }
+
+    // scalar*matrix
+    friend inline mat PURE operator * (pTYPE v, const mat& rhs) {
+        return helpers::doMul(v, rhs);
+    }
+
+    // -----------------------------------------------------------------------
+    // streaming operator to set the columns of the matrix:
+    // example:
+    //    mat33_t m;
+    //    m << v0 << v1 << v2;
+
+    // column_builder<> stores the matrix and knows which column to set
+    template<size_t PREV_COLUMN>
+    struct column_builder {
+        mat& matrix;
+        column_builder(mat& matrix) : matrix(matrix) { }
+    };
+
+    // operator << is not a method of column_builder<> so we can
+    // overload it for unauthorized values (partial specialization
+    // not allowed in class-scope).
+    // we just set the column and return the next column_builder<>
+    template<size_t PREV_COLUMN>
+    friend column_builder<PREV_COLUMN+1> operator << (
+            const column_builder<PREV_COLUMN>& lhs,
+            const vec<TYPE, R>& rhs) {
+        lhs.matrix[PREV_COLUMN+1] = rhs;
+        return column_builder<PREV_COLUMN+1>(lhs.matrix);
+    }
+
+    // we return void here so we get a compile-time error if the
+    // user tries to set too many columns
+    friend void operator << (
+            const column_builder<C-2>& lhs,
+            const vec<TYPE, R>& rhs) {
+        lhs.matrix[C-1] = rhs;
+    }
+
+    // this is where the process starts. we set the first columns and
+    // return the next column_builder<>
+    column_builder<0> operator << (const vec<TYPE, R>& rhs) {
+        (*this)[0] = rhs;
+        return column_builder<0>(*this);
+    }
+};
+
+// Specialize column matrix so they're exactly equivalent to a vector
+template <typename TYPE, size_t R>
+class mat<TYPE, 1, R> : public vec<TYPE, R> {
+    typedef vec<TYPE, R> base;
+public:
+    // STL-like interface.
+    typedef TYPE value_type;
+    typedef TYPE& reference;
+    typedef TYPE const& const_reference;
+    typedef size_t size_type;
+    size_type size() const { return R; }
+    enum { ROWS = R, COLS = 1 };
+
+    mat() { }
+    mat(const base& rhs) : base(rhs) { }
+    mat(const mat& rhs) : base(rhs) { }
+    mat(const TYPE& rhs) { helpers::doAssign(*this, rhs); }
+    mat& operator=(const mat& rhs) { base::operator=(rhs); return *this; }
+    mat& operator=(const base& rhs) { base::operator=(rhs); return *this; }
+    mat& operator=(const TYPE& rhs) { return helpers::doAssign(*this, rhs); }
+    // we only have one column, so ignore the index
+    const base& operator[](size_t) const { return *this; }
+    base& operator[](size_t) { return *this; }
+    void operator << (const vec<TYPE, R>& rhs) { base::operator[](0) = rhs; }
+};
+
+// -----------------------------------------------------------------------
+// matrix functions
+
+// transpose. this handles matrices of matrices
+inline int     PURE transpose(int v)    { return v; }
+inline float   PURE transpose(float v)  { return v; }
+inline double  PURE transpose(double v) { return v; }
+
+// Transpose a matrix
+template <typename TYPE, size_t C, size_t R>
+mat<TYPE, R, C> PURE transpose(const mat<TYPE, C, R>& m) {
+    mat<TYPE, R, C> r;
+    for (size_t i=0 ; i<R ; i++)
+        for (size_t j=0 ; j<C ; j++)
+            r[i][j] = transpose(m[j][i]);
+    return r;
+}
+
+// Calculate the trace of a matrix
+template <typename TYPE, size_t C> static TYPE trace(const mat<TYPE, C, C>& m) {
+    TYPE t;
+    for (size_t i=0 ; i<C ; i++)
+        t += m[i][i];
+    return t;
+}
+
+// Test positive-semidefiniteness of a matrix
+template <typename TYPE, size_t C>
+static bool isPositiveSemidefinite(const mat<TYPE, C, C>& m, TYPE tolerance) {
+    for (size_t i=0 ; i<C ; i++)
+        if (m[i][i] < 0)
+            return false;
+
+    for (size_t i=0 ; i<C ; i++)
+      for (size_t j=i+1 ; j<C ; j++)
+          if (fabs(m[i][j] - m[j][i]) > tolerance)
+              return false;
+
+    return true;
+}
+
+// Transpose a vector
+template <
+    template<typename T, size_t S> class VEC,
+    typename TYPE,
+    size_t SIZE
+>
+mat<TYPE, SIZE, 1> PURE transpose(const VEC<TYPE, SIZE>& v) {
+    mat<TYPE, SIZE, 1> r;
+    for (size_t i=0 ; i<SIZE ; i++)
+        r[i][0] = transpose(v[i]);
+    return r;
+}
+
+// -----------------------------------------------------------------------
+// "dumb" matrix inversion
+template<typename T, size_t N>
+mat<T, N, N> PURE invert(const mat<T, N, N>& src) {
+    T t;
+    size_t swap;
+    mat<T, N, N> tmp(src);
+    mat<T, N, N> inverse(1);
+
+    for (size_t i=0 ; i<N ; i++) {
+        // look for largest element in column
+        swap = i;
+        for (size_t j=i+1 ; j<N ; j++) {
+            if (fabs(tmp[j][i]) > fabs(tmp[i][i])) {
+                swap = j;
+            }
+        }
+
+        if (swap != i) {
+            /* swap rows. */
+            for (size_t k=0 ; k<N ; k++) {
+                t = tmp[i][k];
+                tmp[i][k] = tmp[swap][k];
+                tmp[swap][k] = t;
+
+                t = inverse[i][k];
+                inverse[i][k] = inverse[swap][k];
+                inverse[swap][k] = t;
+            }
+        }
+
+        t = 1 / tmp[i][i];
+        for (size_t k=0 ; k<N ; k++) {
+            tmp[i][k] *= t;
+            inverse[i][k] *= t;
+        }
+        for (size_t j=0 ; j<N ; j++) {
+            if (j != i) {
+                t = tmp[j][i];
+                for (size_t k=0 ; k<N ; k++) {
+                    tmp[j][k] -= tmp[i][k] * t;
+                    inverse[j][k] -= inverse[i][k] * t;
+                }
+            }
+        }
+    }
+    return inverse;
+}
+
+// -----------------------------------------------------------------------
+
+typedef mat<float, 2, 2> mat22_t;
+typedef mat<float, 3, 3> mat33_t;
+typedef mat<float, 4, 4> mat44_t;
+
+// -----------------------------------------------------------------------
+
+}; // namespace android
+
+#endif /* ANDROID_MAT_H */
diff --git a/services/sensorservice/quat.h b/services/sensorservice/quat.h
new file mode 100644
index 0000000..fea1afe
--- /dev/null
+++ b/services/sensorservice/quat.h
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_QUAT_H
+#define ANDROID_QUAT_H
+
+#include <math.h>
+
+#include "vec.h"
+#include "mat.h"
+
+// -----------------------------------------------------------------------
+namespace android {
+// -----------------------------------------------------------------------
+
+template <typename TYPE>
+mat<TYPE, 3, 3> quatToMatrix(const vec<TYPE, 4>& q) {
+    mat<TYPE, 3, 3> R;
+    TYPE q0(q.w);
+    TYPE q1(q.x);
+    TYPE q2(q.y);
+    TYPE q3(q.z);
+    TYPE sq_q1 = 2 * q1 * q1;
+    TYPE sq_q2 = 2 * q2 * q2;
+    TYPE sq_q3 = 2 * q3 * q3;
+    TYPE q1_q2 = 2 * q1 * q2;
+    TYPE q3_q0 = 2 * q3 * q0;
+    TYPE q1_q3 = 2 * q1 * q3;
+    TYPE q2_q0 = 2 * q2 * q0;
+    TYPE q2_q3 = 2 * q2 * q3;
+    TYPE q1_q0 = 2 * q1 * q0;
+    R[0][0] = 1 - sq_q2 - sq_q3;
+    R[0][1] = q1_q2 - q3_q0;
+    R[0][2] = q1_q3 + q2_q0;
+    R[1][0] = q1_q2 + q3_q0;
+    R[1][1] = 1 - sq_q1 - sq_q3;
+    R[1][2] = q2_q3 - q1_q0;
+    R[2][0] = q1_q3 - q2_q0;
+    R[2][1] = q2_q3 + q1_q0;
+    R[2][2] = 1 - sq_q1 - sq_q2;
+    return R;
+}
+
+template <typename TYPE>
+vec<TYPE, 4> matrixToQuat(const mat<TYPE, 3, 3>& R) {
+    // matrix to quaternion
+
+    struct {
+        inline TYPE operator()(TYPE v) {
+            return v < 0 ? 0 : v;
+        }
+    } clamp;
+
+    vec<TYPE, 4> q;
+    const float Hx = R[0].x;
+    const float My = R[1].y;
+    const float Az = R[2].z;
+    q.x = sqrtf( clamp( Hx - My - Az + 1) * 0.25f );
+    q.y = sqrtf( clamp(-Hx + My - Az + 1) * 0.25f );
+    q.z = sqrtf( clamp(-Hx - My + Az + 1) * 0.25f );
+    q.w = sqrtf( clamp( Hx + My + Az + 1) * 0.25f );
+    q.x = copysignf(q.x, R[2].y - R[1].z);
+    q.y = copysignf(q.y, R[0].z - R[2].x);
+    q.z = copysignf(q.z, R[1].x - R[0].y);
+    // guaranteed to be unit-quaternion
+    return q;
+}
+
+template <typename TYPE>
+vec<TYPE, 4> normalize_quat(const vec<TYPE, 4>& q) {
+    vec<TYPE, 4> r(q);
+    if (r.w < 0) {
+        r = -r;
+    }
+    return normalize(r);
+}
+
+// -----------------------------------------------------------------------
+
+typedef vec4_t quat_t;
+
+// -----------------------------------------------------------------------
+}; // namespace android
+
+#endif /* ANDROID_QUAT_H */
diff --git a/services/sensorservice/tests/Android.mk b/services/sensorservice/tests/Android.mk
new file mode 100644
index 0000000..45296dd
--- /dev/null
+++ b/services/sensorservice/tests/Android.mk
@@ -0,0 +1,14 @@
+LOCAL_PATH:= $(call my-dir)
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES:= \
+	sensorservicetest.cpp
+
+LOCAL_SHARED_LIBRARIES := \
+	libcutils libutils libui libgui
+
+LOCAL_MODULE:= test-sensorservice
+
+LOCAL_MODULE_TAGS := optional
+
+include $(BUILD_EXECUTABLE)
diff --git a/services/sensorservice/tests/sensorservicetest.cpp b/services/sensorservice/tests/sensorservicetest.cpp
new file mode 100644
index 0000000..1025fa8
--- /dev/null
+++ b/services/sensorservice/tests/sensorservicetest.cpp
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <android/sensor.h>
+#include <gui/Sensor.h>
+#include <gui/SensorManager.h>
+#include <gui/SensorEventQueue.h>
+#include <utils/Looper.h>
+
+using namespace android;
+
+static nsecs_t sStartTime = 0;
+
+
+int receiver(int fd, int events, void* data)
+{
+    sp<SensorEventQueue> q((SensorEventQueue*)data);
+    ssize_t n;
+    ASensorEvent buffer[8];
+
+    static nsecs_t oldTimeStamp = 0;
+
+    while ((n = q->read(buffer, 8)) > 0) {
+        for (int i=0 ; i<n ; i++) {
+            float t;
+            if (oldTimeStamp) {
+                t = float(buffer[i].timestamp - oldTimeStamp) / s2ns(1);
+            } else {
+                t = float(buffer[i].timestamp - sStartTime) / s2ns(1);
+            }
+            oldTimeStamp = buffer[i].timestamp;
+
+            if (buffer[i].type == Sensor::TYPE_ACCELEROMETER) {
+                printf("%lld\t%8f\t%8f\t%8f\t%f\n",
+                        buffer[i].timestamp,
+                        buffer[i].data[0], buffer[i].data[1], buffer[i].data[2],
+                        1.0/t);
+            }
+
+        }
+    }
+    if (n<0 && n != -EAGAIN) {
+        printf("error reading events (%s)\n", strerror(-n));
+    }
+    return 1;
+}
+
+
+int main(int argc, char** argv)
+{
+    SensorManager& mgr(SensorManager::getInstance());
+
+    Sensor const* const* list;
+    ssize_t count = mgr.getSensorList(&list);
+    printf("numSensors=%d\n", int(count));
+
+    sp<SensorEventQueue> q = mgr.createEventQueue();
+    printf("queue=%p\n", q.get());
+
+    Sensor const* accelerometer = mgr.getDefaultSensor(Sensor::TYPE_ACCELEROMETER);
+    printf("accelerometer=%p (%s)\n",
+            accelerometer, accelerometer->getName().string());
+
+    sStartTime = systemTime();
+
+    q->enableSensor(accelerometer);
+
+    q->setEventRate(accelerometer, ms2ns(10));
+
+    sp<Looper> loop = new Looper(false);
+    loop->addFd(q->getFd(), 0, ALOOPER_EVENT_INPUT, receiver, q.get());
+
+    do {
+        //printf("about to poll...\n");
+        int32_t ret = loop->pollOnce(-1);
+        switch (ret) {
+            case ALOOPER_POLL_WAKE:
+                //("ALOOPER_POLL_WAKE\n");
+                break;
+            case ALOOPER_POLL_CALLBACK:
+                //("ALOOPER_POLL_CALLBACK\n");
+                break;
+            case ALOOPER_POLL_TIMEOUT:
+                printf("ALOOPER_POLL_TIMEOUT\n");
+                break;
+            case ALOOPER_POLL_ERROR:
+                printf("ALOOPER_POLL_TIMEOUT\n");
+                break;
+            default:
+                printf("ugh? poll returned %d\n", ret);
+                break;
+        }
+    } while (1);
+
+
+    return 0;
+}
diff --git a/services/sensorservice/traits.h b/services/sensorservice/traits.h
new file mode 100644
index 0000000..da4c599
--- /dev/null
+++ b/services/sensorservice/traits.h
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_TRAITS_H
+#define ANDROID_TRAITS_H
+
+// -----------------------------------------------------------------------
+// Typelists
+
+namespace android {
+
+// end-of-list marker
+class NullType {};
+
+// type-list node
+template <typename T, typename U>
+struct TypeList {
+    typedef T Head;
+    typedef U Tail;
+};
+
+// helpers to build typelists
+#define TYPELIST_1(T1) TypeList<T1, NullType>
+#define TYPELIST_2(T1, T2) TypeList<T1, TYPELIST_1(T2)>
+#define TYPELIST_3(T1, T2, T3) TypeList<T1, TYPELIST_2(T2, T3)>
+#define TYPELIST_4(T1, T2, T3, T4) TypeList<T1, TYPELIST_3(T2, T3, T4)>
+
+// typelists algorithms
+namespace TL {
+template <typename TList, typename T> struct IndexOf;
+
+template <typename T>
+struct IndexOf<NullType, T> {
+    enum { value = -1 };
+};
+
+template <typename T, typename Tail>
+struct IndexOf<TypeList<T, Tail>, T> {
+    enum { value = 0 };
+};
+
+template <typename Head, typename Tail, typename T>
+struct IndexOf<TypeList<Head, Tail>, T> {
+private:
+    enum { temp = IndexOf<Tail, T>::value };
+public:
+    enum { value = temp == -1 ? -1 : 1 + temp };
+};
+
+}; // namespace TL
+
+// type selection based on a boolean
+template <bool flag, typename T, typename U>
+struct Select {
+    typedef T Result;
+};
+template <typename T, typename U>
+struct Select<false, T, U> {
+    typedef U Result;
+};
+
+// -----------------------------------------------------------------------
+// Type traits
+
+template <typename T>
+class TypeTraits {
+    typedef TYPELIST_4(
+            unsigned char, unsigned short,
+            unsigned int, unsigned long int) UnsignedInts;
+
+    typedef TYPELIST_4(
+            signed char, signed short,
+            signed int, signed long int) SignedInts;
+
+    typedef TYPELIST_1(
+            bool) OtherInts;
+
+    typedef TYPELIST_3(
+            float, double, long double) Floats;
+
+    template<typename U> struct PointerTraits {
+        enum { result = false };
+        typedef NullType PointeeType;
+    };
+    template<typename U> struct PointerTraits<U*> {
+        enum { result = true };
+        typedef U PointeeType;
+    };
+
+public:
+    enum { isStdUnsignedInt = TL::IndexOf<UnsignedInts, T>::value >= 0 };
+    enum { isStdSignedInt   = TL::IndexOf<SignedInts,   T>::value >= 0 };
+    enum { isStdIntegral    = TL::IndexOf<OtherInts,    T>::value >= 0 || isStdUnsignedInt || isStdSignedInt };
+    enum { isStdFloat       = TL::IndexOf<Floats,       T>::value >= 0 };
+    enum { isPointer        = PointerTraits<T>::result };
+    enum { isStdArith       = isStdIntegral || isStdFloat };
+
+    // best parameter type for given type
+    typedef typename Select<isStdArith || isPointer, T, const T&>::Result ParameterType;
+};
+
+// -----------------------------------------------------------------------
+}; // namespace android
+
+#endif /* ANDROID_TRAITS_H */
diff --git a/services/sensorservice/vec.h b/services/sensorservice/vec.h
new file mode 100644
index 0000000..24f30ff
--- /dev/null
+++ b/services/sensorservice/vec.h
@@ -0,0 +1,438 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_VEC_H
+#define ANDROID_VEC_H
+
+#include <math.h>
+
+#include <stdint.h>
+#include <stddef.h>
+
+#include "traits.h"
+
+// -----------------------------------------------------------------------
+
+#define PURE __attribute__((pure))
+
+namespace android {
+
+// -----------------------------------------------------------------------
+// non-inline helpers
+
+template <typename TYPE, size_t SIZE>
+class vec;
+
+template <typename TYPE, size_t SIZE>
+class vbase;
+
+namespace helpers {
+
+template <typename T> inline T min(T a, T b) { return a<b ? a : b; }
+template <typename T> inline T max(T a, T b) { return a>b ? a : b; }
+
+template < template<typename T, size_t S> class VEC,
+    typename TYPE, size_t SIZE, size_t S>
+vec<TYPE, SIZE>& doAssign(
+        vec<TYPE, SIZE>& lhs, const VEC<TYPE, S>& rhs) {
+    const size_t minSize = min(SIZE, S);
+    const size_t maxSize = max(SIZE, S);
+    for (size_t i=0 ; i<minSize ; i++)
+        lhs[i] = rhs[i];
+    for (size_t i=minSize ; i<maxSize ; i++)
+        lhs[i] = 0;
+    return lhs;
+}
+
+
+template <
+    template<typename T, size_t S> class VLHS,
+    template<typename T, size_t S> class VRHS,
+    typename TYPE,
+    size_t SIZE
+>
+VLHS<TYPE, SIZE> PURE doAdd(
+        const VLHS<TYPE, SIZE>& lhs,
+        const VRHS<TYPE, SIZE>& rhs) {
+    VLHS<TYPE, SIZE> r;
+    for (size_t i=0 ; i<SIZE ; i++)
+        r[i] = lhs[i] + rhs[i];
+    return r;
+}
+
+template <
+    template<typename T, size_t S> class VLHS,
+    template<typename T, size_t S> class VRHS,
+    typename TYPE,
+    size_t SIZE
+>
+VLHS<TYPE, SIZE> PURE doSub(
+        const VLHS<TYPE, SIZE>& lhs,
+        const VRHS<TYPE, SIZE>& rhs) {
+    VLHS<TYPE, SIZE> r;
+    for (size_t i=0 ; i<SIZE ; i++)
+        r[i] = lhs[i] - rhs[i];
+    return r;
+}
+
+template <
+    template<typename T, size_t S> class VEC,
+    typename TYPE,
+    size_t SIZE
+>
+VEC<TYPE, SIZE> PURE doMulScalar(
+        const VEC<TYPE, SIZE>& lhs,
+        typename TypeTraits<TYPE>::ParameterType rhs) {
+    VEC<TYPE, SIZE> r;
+    for (size_t i=0 ; i<SIZE ; i++)
+        r[i] = lhs[i] * rhs;
+    return r;
+}
+
+template <
+    template<typename T, size_t S> class VEC,
+    typename TYPE,
+    size_t SIZE
+>
+VEC<TYPE, SIZE> PURE doScalarMul(
+        typename TypeTraits<TYPE>::ParameterType lhs,
+        const VEC<TYPE, SIZE>& rhs) {
+    VEC<TYPE, SIZE> r;
+    for (size_t i=0 ; i<SIZE ; i++)
+        r[i] = lhs * rhs[i];
+    return r;
+}
+
+}; // namespace helpers
+
+// -----------------------------------------------------------------------
+// Below we define the mathematical operators for vectors.
+// We use template template arguments so we can generically
+// handle the case where the right-hand-size and left-hand-side are
+// different vector types (but with same value_type and size).
+// This is needed for performance when using ".xy{z}" element access
+// on vec<>. Without this, an extra conversion to vec<> would be needed.
+//
+// example:
+//      vec4_t a;
+//      vec3_t b;
+//      vec3_t c = a.xyz + b;
+//
+//  "a.xyz + b" is a mixed-operation between a vbase<> and a vec<>, requiring
+//  a conversion of vbase<> to vec<>. The template gunk below avoids this,
+// by allowing the addition on these different vector types directly
+//
+
+template <
+    template<typename T, size_t S> class VLHS,
+    template<typename T, size_t S> class VRHS,
+    typename TYPE,
+    size_t SIZE
+>
+inline VLHS<TYPE, SIZE> PURE operator + (
+        const VLHS<TYPE, SIZE>& lhs,
+        const VRHS<TYPE, SIZE>& rhs) {
+    return helpers::doAdd(lhs, rhs);
+}
+
+template <
+    template<typename T, size_t S> class VLHS,
+    template<typename T, size_t S> class VRHS,
+    typename TYPE,
+    size_t SIZE
+>
+inline VLHS<TYPE, SIZE> PURE operator - (
+        const VLHS<TYPE, SIZE>& lhs,
+        const VRHS<TYPE, SIZE>& rhs) {
+    return helpers::doSub(lhs, rhs);
+}
+
+template <
+    template<typename T, size_t S> class VEC,
+    typename TYPE,
+    size_t SIZE
+>
+inline VEC<TYPE, SIZE> PURE operator * (
+        const VEC<TYPE, SIZE>& lhs,
+        typename TypeTraits<TYPE>::ParameterType rhs) {
+    return helpers::doMulScalar(lhs, rhs);
+}
+
+template <
+    template<typename T, size_t S> class VEC,
+    typename TYPE,
+    size_t SIZE
+>
+inline VEC<TYPE, SIZE> PURE operator * (
+        typename TypeTraits<TYPE>::ParameterType lhs,
+        const VEC<TYPE, SIZE>& rhs) {
+    return helpers::doScalarMul(lhs, rhs);
+}
+
+
+template <
+    template<typename T, size_t S> class VLHS,
+    template<typename T, size_t S> class VRHS,
+    typename TYPE,
+    size_t SIZE
+>
+TYPE PURE dot_product(
+        const VLHS<TYPE, SIZE>& lhs,
+        const VRHS<TYPE, SIZE>& rhs) {
+    TYPE r(0);
+    for (size_t i=0 ; i<SIZE ; i++)
+        r += lhs[i] * rhs[i];
+    return r;
+}
+
+template <
+    template<typename T, size_t S> class V,
+    typename TYPE,
+    size_t SIZE
+>
+TYPE PURE length(const V<TYPE, SIZE>& v) {
+    return sqrt(dot_product(v, v));
+}
+
+template <
+    template<typename T, size_t S> class V,
+    typename TYPE,
+    size_t SIZE
+>
+TYPE PURE length_squared(const V<TYPE, SIZE>& v) {
+    return dot_product(v, v);
+}
+
+template <
+    template<typename T, size_t S> class V,
+    typename TYPE,
+    size_t SIZE
+>
+V<TYPE, SIZE> PURE normalize(const V<TYPE, SIZE>& v) {
+    return v * (1/length(v));
+}
+
+template <
+    template<typename T, size_t S> class VLHS,
+    template<typename T, size_t S> class VRHS,
+    typename TYPE
+>
+VLHS<TYPE, 3> PURE cross_product(
+        const VLHS<TYPE, 3>& u,
+        const VRHS<TYPE, 3>& v) {
+    VLHS<TYPE, 3> r;
+    r.x = u.y*v.z - u.z*v.y;
+    r.y = u.z*v.x - u.x*v.z;
+    r.z = u.x*v.y - u.y*v.x;
+    return r;
+}
+
+
+template <typename TYPE, size_t SIZE>
+vec<TYPE, SIZE> PURE operator - (const vec<TYPE, SIZE>& lhs) {
+    vec<TYPE, SIZE> r;
+    for (size_t i=0 ; i<SIZE ; i++)
+        r[i] = -lhs[i];
+    return r;
+}
+
+// -----------------------------------------------------------------------
+
+// This our basic vector type, it just implements the data storage
+// and accessors.
+
+template <typename TYPE, size_t SIZE>
+struct vbase {
+    TYPE v[SIZE];
+    inline const TYPE& operator[](size_t i) const { return v[i]; }
+    inline       TYPE& operator[](size_t i)       { return v[i]; }
+};
+template<> struct vbase<float, 2> {
+    union {
+        float v[2];
+        struct { float x, y; };
+        struct { float s, t; };
+    };
+    inline const float& operator[](size_t i) const { return v[i]; }
+    inline       float& operator[](size_t i)       { return v[i]; }
+};
+template<> struct vbase<float, 3> {
+    union {
+        float v[3];
+        struct { float x, y, z; };
+        struct { float s, t, r; };
+        vbase<float, 2> xy;
+        vbase<float, 2> st;
+    };
+    inline const float& operator[](size_t i) const { return v[i]; }
+    inline       float& operator[](size_t i)       { return v[i]; }
+};
+template<> struct vbase<float, 4> {
+    union {
+        float v[4];
+        struct { float x, y, z, w; };
+        struct { float s, t, r, q; };
+        vbase<float, 3> xyz;
+        vbase<float, 3> str;
+        vbase<float, 2> xy;
+        vbase<float, 2> st;
+    };
+    inline const float& operator[](size_t i) const { return v[i]; }
+    inline       float& operator[](size_t i)       { return v[i]; }
+};
+
+// -----------------------------------------------------------------------
+
+template <typename TYPE, size_t SIZE>
+class vec : public vbase<TYPE, SIZE>
+{
+    typedef typename TypeTraits<TYPE>::ParameterType pTYPE;
+    typedef vbase<TYPE, SIZE> base;
+
+public:
+    // STL-like interface.
+    typedef TYPE value_type;
+    typedef TYPE& reference;
+    typedef TYPE const& const_reference;
+    typedef size_t size_type;
+
+    typedef TYPE* iterator;
+    typedef TYPE const* const_iterator;
+    iterator begin() { return base::v; }
+    iterator end() { return base::v + SIZE; }
+    const_iterator begin() const { return base::v; }
+    const_iterator end() const { return base::v + SIZE; }
+    size_type size() const { return SIZE; }
+
+    // -----------------------------------------------------------------------
+    // default constructors
+
+    vec() { }
+    vec(const vec& rhs)  : base(rhs) { }
+    vec(const base& rhs) : base(rhs) { }
+
+    // -----------------------------------------------------------------------
+    // conversion constructors
+
+    vec(pTYPE rhs) {
+        for (size_t i=0 ; i<SIZE ; i++)
+            base::operator[](i) = rhs;
+    }
+
+    template < template<typename T, size_t S> class VEC, size_t S>
+    explicit vec(const VEC<TYPE, S>& rhs) {
+        helpers::doAssign(*this, rhs);
+    }
+
+    explicit vec(TYPE const* array) {
+        for (size_t i=0 ; i<SIZE ; i++)
+            base::operator[](i) = array[i];
+    }
+
+    // -----------------------------------------------------------------------
+    // Assignment
+
+    vec& operator = (const vec& rhs) {
+        base::operator=(rhs);
+        return *this;
+    }
+
+    vec& operator = (const base& rhs) {
+        base::operator=(rhs);
+        return *this;
+    }
+
+    vec& operator = (pTYPE rhs) {
+        for (size_t i=0 ; i<SIZE ; i++)
+            base::operator[](i) = rhs;
+        return *this;
+    }
+
+    template < template<typename T, size_t S> class VEC, size_t S>
+    vec& operator = (const VEC<TYPE, S>& rhs) {
+        return helpers::doAssign(*this, rhs);
+    }
+
+    // -----------------------------------------------------------------------
+    // operation-assignment
+
+    vec& operator += (const vec& rhs);
+    vec& operator -= (const vec& rhs);
+    vec& operator *= (pTYPE rhs);
+
+    // -----------------------------------------------------------------------
+    // non-member function declaration and definition
+    // NOTE: we declare the non-member function as friend inside the class
+    // so that they are known to the compiler when the class is instantiated.
+    // This helps the compiler doing template argument deduction when the
+    // passed types are not identical. Essentially this helps with
+    // type conversion so that you can multiply a vec<float> by an scalar int
+    // (for instance).
+
+    friend inline vec PURE operator + (const vec& lhs, const vec& rhs) {
+        return helpers::doAdd(lhs, rhs);
+    }
+    friend inline vec PURE operator - (const vec& lhs, const vec& rhs) {
+        return helpers::doSub(lhs, rhs);
+    }
+    friend inline vec PURE operator * (const vec& lhs, pTYPE v) {
+        return helpers::doMulScalar(lhs, v);
+    }
+    friend inline vec PURE operator * (pTYPE v, const vec& rhs) {
+        return helpers::doScalarMul(v, rhs);
+    }
+    friend inline TYPE PURE dot_product(const vec& lhs, const vec& rhs) {
+        return android::dot_product(lhs, rhs);
+    }
+};
+
+// -----------------------------------------------------------------------
+
+template <typename TYPE, size_t SIZE>
+vec<TYPE, SIZE>& vec<TYPE, SIZE>::operator += (const vec<TYPE, SIZE>& rhs) {
+    vec<TYPE, SIZE>& lhs(*this);
+    for (size_t i=0 ; i<SIZE ; i++)
+        lhs[i] += rhs[i];
+    return lhs;
+}
+
+template <typename TYPE, size_t SIZE>
+vec<TYPE, SIZE>& vec<TYPE, SIZE>::operator -= (const vec<TYPE, SIZE>& rhs) {
+    vec<TYPE, SIZE>& lhs(*this);
+    for (size_t i=0 ; i<SIZE ; i++)
+        lhs[i] -= rhs[i];
+    return lhs;
+}
+
+template <typename TYPE, size_t SIZE>
+vec<TYPE, SIZE>& vec<TYPE, SIZE>::operator *= (vec<TYPE, SIZE>::pTYPE rhs) {
+    vec<TYPE, SIZE>& lhs(*this);
+    for (size_t i=0 ; i<SIZE ; i++)
+        lhs[i] *= rhs;
+    return lhs;
+}
+
+// -----------------------------------------------------------------------
+
+typedef vec<float, 2> vec2_t;
+typedef vec<float, 3> vec3_t;
+typedef vec<float, 4> vec4_t;
+
+// -----------------------------------------------------------------------
+
+}; // namespace android
+
+#endif /* ANDROID_VEC_H */