a2dp hw: adding a2dp tuning through bdroid_buildcfg.h

This adds possibility to configure a2dp tuning on an
arbitrary sysfs path and arbitrary ON/OFF values.
It's activated when a2dp is being used, and
deactivates when a2dp is stopped.
This way a device can either use an a2dp_tuning sysfs file
or cpu scaling min freq sysfs path with a target
min_freq value for elevation.

Here are two example of the two strategies of usage for
this:
bdroid_buildcfg.h - sysfs tuning file
 #define A2DP_HW_SYSFS_TUNER "/sys/devices/platform/tegra_uart.2/a2dp_tuning"
 #define A2DP_HW_SYSFS_TUNER_OFF "0"
 #define A2DP_HW_SYSFS_TUNER_ON "1"

bdroid_buildcfg.h - scaling min freq file
 #define A2DP_HW_SYSFS_TUNER "/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq"
 #define A2DP_HW_SYSFS_TUNER_OFF "0"
 #define A2DP_HW_SYSFS_TUNER_ON "204000"

Change-Id: I2cd94e626eb2a6d04a6e52ddac94fa5773eb09d8

3 files changed, 50 insertions, 1 deletions

diff --git a/audio_a2dp_hw/Android.mk b/audio_a2dp_hw/Android.mk
index bf00342..5adae79 100644
--- a/audio_a2dp_hw/Android.mk
+++ b/audio_a2dp_hw/Android.mk
@@ -11,7 +11,10 @@ endif
 LOCAL_SRC_FILES:= \
 	audio_a2dp_hw.c
 
-LOCAL_C_INCLUDES+= .
+LOCAL_CFLAGS += $(bdroid_CFLAGS)
+
+LOCAL_C_INCLUDES+= . \
+	$(bdroid_C_INCLUDES)
 
 LOCAL_SHARED_LIBRARIES := \
 	libcutils
diff --git a/audio_a2dp_hw/audio_a2dp_hw.c b/audio_a2dp_hw/audio_a2dp_hw.c
index 42e416e..e1a99c5 100644
--- a/audio_a2dp_hw/audio_a2dp_hw.c
+++ b/audio_a2dp_hw/audio_a2dp_hw.c
@@ -142,6 +142,34 @@ static const char* dump_a2dp_ctrl_event(char event)
     }
 }
 
+#ifdef A2DP_HW_SYSFS_TUNER
+/* If kernel supports some kind of A2DP related tuning,
+   this function should be used to switch tuning on/off.
+   Specify in BLUEDROID BUILDCFG the following values:
+   A2DP_HW_SYSFS_TUNER "/sysfs/path/to/tuner/or/scaling_min_freq"
+   A2DP_HW_SYSFS_TUNER_OFF "0"   # value to switch tuning off,
+                                 # "0" or a Min Freq off value
+                                 # like "0"
+   A2DP_HW_SYSFS_TUNER_ON "1"    # value to switch tuning on
+                                 # "1", or Min Freq boost value
+                                 # like "205000"
+*/
+static void a2dp_hw_sysfs_tuning(int state)
+{
+    int fd = open( A2DP_HW_SYSFS_TUNER, O_WRONLY);
+    if(fd > 0) {
+        char *val = A2DP_HW_SYSFS_TUNER_OFF;
+        if (state)
+        {
+            val = A2DP_HW_SYSFS_TUNER_ON;
+        }
+        write(fd, val, strlen(val));
+        INFO("a2dp tuning set to %s", val);
+        close(fd);
+    }
+}
+#endif
+
 /* logs timestamp with microsec precision
    pprev is optional in case a dedicated diff is required */
 static void ts_log(char *tag, int val, struct timespec *pprev_opt)
@@ -356,6 +384,9 @@ static int start_audio_datapath(struct a2dp_stream_out *out)
         out->state = AUDIO_A2DP_STATE_STARTED;
     }
 
+#ifdef A2DP_HW_SYSFS_TUNER
+    a2dp_hw_sysfs_tuning(1);
+#endif
     return 0;
 }
 
@@ -366,6 +397,11 @@ static int stop_audio_datapath(struct a2dp_stream_out *out)
 
     INFO("state %d", out->state);
 
+#ifdef A2DP_HW_SYSFS_TUNER
+    /* disable a2dp tuning  ASAP */
+    a2dp_hw_sysfs_tuning(0);
+#endif
+
     if (out->ctrl_fd == AUDIO_SKT_DISCONNECTED)
          return -1;
 
@@ -393,6 +429,11 @@ static int suspend_audio_datapath(struct a2dp_stream_out *out, bool standby)
 {
     INFO("state %d", out->state);
 
+#ifdef A2DP_HW_SYSFS_TUNER
+    /* disable a2dp tuning ASAP */
+    a2dp_hw_sysfs_tuning(0);
+#endif
+
     if (out->ctrl_fd == AUDIO_SKT_DISCONNECTED)
          return -1;
 
diff --git a/audio_a2dp_hw/audio_a2dp_hw.h b/audio_a2dp_hw/audio_a2dp_hw.h
index 3076a6d..4a9f1a9 100644
--- a/audio_a2dp_hw/audio_a2dp_hw.h
+++ b/audio_a2dp_hw/audio_a2dp_hw.h
@@ -28,6 +28,11 @@
 #ifndef AUDIO_A2DP_HW_H
 #define AUDIO_A2DP_HW_H
 
+#ifdef HAS_BDROID_BUILDCFG
+#include "bdroid_buildcfg.h"
+#endif
+
+
 /*****************************************************************************
 **  Constants & Macros
 ******************************************************************************/