audio: MMAP NOIRQ mode shareable file descriptor

Derive a shareable file descriptor for the DMA buffer
used for MMAP NOIRQ

Change-Id: Ibdd633fad35ed397f6de746e5755a02522e39777
diff --git a/hal/audio_hw.c b/hal/audio_hw.c
index ca891ac..8b44cd5 100644
--- a/hal/audio_hw.c
+++ b/hal/audio_hw.c
@@ -4128,6 +4128,7 @@
     unsigned int offset1;
     unsigned int frames1;
     const char *step = "";
+    uint32_t mmap_size;
 
     ALOGV("%s", __func__);
     pthread_mutex_lock(&adev->lock);
@@ -4168,10 +4169,16 @@
     }
     info->buffer_size_frames = pcm_get_buffer_size(out->pcm);
     info->burst_size_frames = out->config.period_size;
-    info->shared_memory_fd = pcm_get_poll_fd(out->pcm);
-
+    ret = platform_get_mmap_data_fd(adev->platform,
+                                    out->pcm_device_id, 0 /*playback*/,
+                                    &info->shared_memory_fd,
+                                    &mmap_size);
+    if (ret < 0) {
+        step = "get_mmap_fd";
+        goto exit;
+    }
     memset(info->shared_memory_address, 0, pcm_frames_to_bytes(out->pcm,
-                                                                info->buffer_size_frames));
+                                                               info->buffer_size_frames));
 
     ret = pcm_mmap_commit(out->pcm, 0, MMAP_PERIOD_SIZE);
     if (ret < 0) {
diff --git a/hal/msm8916/platform.c b/hal/msm8916/platform.c
index 2bdcf62..7778b2b 100644
--- a/hal/msm8916/platform.c
+++ b/hal/msm8916/platform.c
@@ -40,6 +40,10 @@
 #include <dirent.h>
 #include <linux/msm_audio.h>
 
+#if defined(PLATFORM_MSMFALCON)
+#include <sound/devdep_params.h>
+#endif
+
 #ifdef DYNAMIC_LOG_ENABLED
 #include <log_xml_parser.h>
 #define LOG_MASK HAL_MOD_FILE_PLATFORM
@@ -7229,3 +7233,40 @@
 
     return MAX_CODEC_BACKENDS;
 }
+
+#if defined(PLATFORM_MSMFALCON)
+int platform_get_mmap_data_fd(void *platform, int fe_dev, int dir, int *fd,
+                              uint32_t *size)
+{
+    struct platform_data *my_data = (struct platform_data *)platform;
+    struct audio_device *adev = my_data->adev;
+    int hw_fd = -1;
+    char dev_name[128];
+    struct snd_pcm_mmap_fd mmap_fd;
+    memset(&mmap_fd, 0, sizeof(mmap_fd));
+    mmap_fd.dir = dir;
+    snprintf(dev_name, sizeof(dev_name), "/dev/snd/hwC%uD%u",
+             adev->snd_card, HWDEP_FE_BASE+fe_dev);
+    hw_fd = open(dev_name, O_RDONLY);
+    if (hw_fd < 0) {
+        ALOGE("fe hw dep node open %d/%d failed", adev->snd_card, fe_dev);
+        return -1;
+    }
+    if (ioctl(hw_fd, SNDRV_PCM_IOCTL_MMAP_DATA_FD, &mmap_fd) < 0) {
+        ALOGE("fe hw dep node ioctl failed");
+        close(hw_fd);
+        return -1;
+    }
+    *fd = mmap_fd.fd;
+    *size = mmap_fd.size;
+    close(hw_fd); // mmap_fd should still be valid
+    return 0;
+}
+#else
+int platform_get_mmap_data_fd(void *platform __unused, int fe_dev __unused,
+                              int dir __unused, int *fd __unused,
+                              uint32_t *size __unused)
+{
+    return -1;
+}
+#endif
diff --git a/hal/msm8960/platform.c b/hal/msm8960/platform.c
index f2201db..43aeaed 100644
--- a/hal/msm8960/platform.c
+++ b/hal/msm8960/platform.c
@@ -1368,3 +1368,9 @@
 {
     return 0;
 }
+
+int platform_get_mmap_data_fd(void *platform, int fe_dev, int dir, int *fd,
+                              uint32_t *size)
+{
+    return -ENOSYS;
+}
diff --git a/hal/msm8974/platform.c b/hal/msm8974/platform.c
index ccaee95..1d787d0 100644
--- a/hal/msm8974/platform.c
+++ b/hal/msm8974/platform.c
@@ -75,6 +75,9 @@
 #endif
 
 #include <linux/msm_audio.h>
+#if defined (PLATFORM_MSM8998) || (PLATFORM_SDM845)
+#include <sound/devdep_params.h>
+#endif
 
 #define LIB_ACDB_LOADER "libacdbloader.so"
 #define CVD_VERSION_MIXER_CTL "CVD Version"
@@ -7008,3 +7011,40 @@
 
     return MAX_CODEC_BACKENDS;
 }
+
+#if defined (PLATFORM_MSM8998) || (PLATFORM_SDM845)
+int platform_get_mmap_data_fd(void *platform, int fe_dev, int dir, int *fd,
+                              uint32_t *size)
+{
+    struct platform_data *my_data = (struct platform_data *)platform;
+    struct audio_device *adev = my_data->adev;
+    int hw_fd = -1;
+    char dev_name[128];
+    struct snd_pcm_mmap_fd mmap_fd;
+    memset(&mmap_fd, 0, sizeof(mmap_fd));
+    mmap_fd.dir = dir;
+    snprintf(dev_name, sizeof(dev_name), "/dev/snd/hwC%uD%u",
+             adev->snd_card, HWDEP_FE_BASE+fe_dev);
+    hw_fd = open(dev_name, O_RDONLY);
+    if (hw_fd < 0) {
+        ALOGE("fe hw dep node open %d/%d failed", adev->snd_card, fe_dev);
+        return -1;
+    }
+    if (ioctl(hw_fd, SNDRV_PCM_IOCTL_MMAP_DATA_FD, &mmap_fd) < 0) {
+        ALOGE("fe hw dep node ioctl failed");
+        close(hw_fd);
+        return -1;
+    }
+    *fd = mmap_fd.fd;
+    *size = mmap_fd.size;
+    close(hw_fd); // mmap_fd should still be valid
+    return 0;
+}
+#else
+int platform_get_mmap_data_fd(void *platform __unused, int fe_dev __unused,
+                              int dir __unused, int *fd __unused,
+                              uint32_t *size __unused)
+{
+    return -1;
+}
+#endif
diff --git a/hal/platform_api.h b/hal/platform_api.h
index 3c31c56..9a34582 100644
--- a/hal/platform_api.h
+++ b/hal/platform_api.h
@@ -230,4 +230,6 @@
 void platform_check_and_update_copp_sample_rate(void *platform, snd_device_t snd_device,
      unsigned int stream_sr,int *sample_rate);
 int platform_get_max_codec_backend();
+int platform_get_mmap_data_fd(void *platform, int dev, int dir,
+                               int *fd, uint32_t *size);
 #endif // AUDIO_PLATFORM_API_H