hal: Add XML parser for platform info

change 1
Add XML parser which parses the platform_info.xml
on the device. That xml contains ACDB ID information
and is populated from the device project folder to
the /etc folder on the device. It is used to overwrite
hardcoded ACDB ID's in platform.c.

change 2
Move platform_parser to root hal directory. Rename
platform_parser to platform_info. Change name of
XML file read from platform_info.xml to
audio_platform_info.xml. The xml now only needs
information for ACDB ID's that you want overwritten.
Names in the XML now match sound device enums in
platform.c.

(cherry-picked from CAF commits
61764e3b8069b819c3da19a6bb38b37ad173bf50, 5588688cbdd065a3572afb032e48a265790dfea2)

Change-Id: Ie5978f609bbe9d60a64e20a0906d6bd7a8c48e1b
diff --git a/hal/platform_info.c b/hal/platform_info.c
new file mode 100644
index 0000000..409c396
--- /dev/null
+++ b/hal/platform_info.c
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2014 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.
+*/
+
+#define LOG_TAG "platform_info"
+#define LOG_NDDEBUG 0
+
+#include <errno.h>
+#include <stdio.h>
+#include <expat.h>
+#include <cutils/log.h>
+#include <audio_hw.h>
+#include "platform_api.h"
+#include <platform.h>
+
+#define PLATFORM_INFO_XML_PATH      "/system/etc/audio_platform_info.xml"
+
+static void process_device(const XML_Char **attr)
+{
+    int index;
+
+    if (strcmp(attr[0], "name") != 0) {
+        ALOGE("%s: 'name' not found, no ACDB ID set!", __func__);
+        goto done;
+    }
+
+    index = platform_get_snd_device_index((char *)attr[1]);
+    if (index < 0) {
+        ALOGE("%s: Device %s in %s not found, no ACDB ID set!",
+              __func__, attr[1], PLATFORM_INFO_XML_PATH);
+        goto done;
+    }
+
+    if (strcmp(attr[2], "acdb_id") != 0) {
+        ALOGE("%s: Device %s in %s has no acdb_id, no ACDB ID set!",
+              __func__, attr[1], PLATFORM_INFO_XML_PATH);
+        goto done;
+    }
+
+    if(platform_set_snd_device_acdb_id(index, atoi((char *)attr[3])) < 0) {
+        ALOGE("%s: Device %s in %s, ACDB ID %d was not set!",
+              __func__, attr[1], PLATFORM_INFO_XML_PATH, atoi((char *)attr[3]));
+        goto done;
+    }
+
+done:
+    return;
+}
+
+static void start_tag(void *userdata __unused, const XML_Char *tag_name,
+                      const XML_Char **attr)
+{
+    const XML_Char              *attr_name = NULL;
+    const XML_Char              *attr_value = NULL;
+    unsigned int                i;
+
+    if (strcmp(tag_name, "device") == 0)
+        process_device(attr);
+
+    return;
+}
+
+static void end_tag(void *userdata __unused, const XML_Char *tag_name __unused)
+{
+
+}
+
+int platform_info_init(void)
+{
+    XML_Parser      parser;
+    FILE            *file;
+    int             ret = 0;
+    int             bytes_read;
+    void            *buf;
+    static const uint32_t kBufSize = 1024;
+
+    file = fopen(PLATFORM_INFO_XML_PATH, "r");
+    if (!file) {
+        ALOGD("%s: Failed to open %s, using defaults.",
+            __func__, PLATFORM_INFO_XML_PATH);
+        ret = -ENODEV;
+        goto done;
+    }
+
+    parser = XML_ParserCreate(NULL);
+    if (!parser) {
+        ALOGE("%s: Failed to create XML parser!", __func__);
+        ret = -ENODEV;
+        goto err_close_file;
+    }
+
+    XML_SetElementHandler(parser, start_tag, end_tag);
+
+    while (1) {
+        buf = XML_GetBuffer(parser, kBufSize);
+        if (buf == NULL) {
+            ALOGE("%s: XML_GetBuffer failed", __func__);
+            ret = -ENOMEM;
+            goto err_free_parser;
+        }
+
+        bytes_read = fread(buf, 1, kBufSize, file);
+        if (bytes_read < 0) {
+            ALOGE("%s: fread failed, bytes read = %d", __func__, bytes_read);
+             ret = bytes_read;
+            goto err_free_parser;
+        }
+
+        if (XML_ParseBuffer(parser, bytes_read,
+                            bytes_read == 0) == XML_STATUS_ERROR) {
+            ALOGE("%s: XML_ParseBuffer failed, for %s",
+                __func__, PLATFORM_INFO_XML_PATH);
+            ret = -EINVAL;
+            goto err_free_parser;
+        }
+
+        if (bytes_read == 0)
+            break;
+    }
+
+err_free_parser:
+    XML_ParserFree(parser);
+err_close_file:
+    fclose(file);
+done:
+    return ret;
+}