sony_msm8x60: ASoc miscelleneous changes (squashed commit)

This is a squash of these commits : -
fb2012ec ASoC: msm: proper error code for drain ioctl
9ed7769 ASoC: msm: avoid negative time stamp check
dcc29ce ASoC: msm: Resume writes only for start command
84772b3 ASoC: msm: Fixes for underrun issue in LPA Playback
a4334ff ALSA: include: Add new ioctl for metadata mode
bf918e2 ASoC: core: Update ALSA core to issue restart in underrun.

From codeaurora forums.

======================================================================

ASoC: core: Update ALSA core to issue restart in underrun.

When compressed and pcm session is started the buffer pull will
Be from the DSP, in mmap mode for the scenario Hardware pointer
Is same as application pointer implies application has not filled the
Buffer to be send to DSP, and platform driver has to break and restart
The de queue process when the application has sufficient buffers.

When hardware pointer is same as application pointer it is an under run
Scenario where the ALSA framework has to trigger the under run and in HAL
The session has to re-prepare and re-triggered. based on the stop
Threshold, but in our system the stop threshold is INT_MAX which
Indicates that under run is not triggered in practical cases.

We have a brodcast usecase in which the mentioned under run case
Is hit mulitple times, and every time re-prepare and re-trigger will be
Expensive

Update the ASoC core framework to restart de queue process stopped
By platform Driver when the under run is hit, based on the available
Buffer and render flag, so the System will recover from the hang state.

To restart de queue process the ASoC core will be calling the restart
Callback registered by platform driver and this callback will be running in
Atomic context.

Change-Id: Ic9ea05a0dc6246346e9913493232882e2f5447d1
Signed-off-by: Santosh Mardi <gsantosh@codeaurora.org>

ALSA: include: Add new ioctl for metadata mode

Add a new ioctl to support metadata mode in lpa driver. This ioctl
allows lpa driver to work in default alsa compliant mode and also
metadata mode.

CRs-Fixed: 458904
Change-Id: I8111e8652bbfb6dd93bdbda69bd16f53b45cb756
Signed-off-by: Krishnankutty Kolathappilly <kkolat@codeaurora.org>

ASoC: msm: Fixes for underrun issue in LPA Playback

Update LPA platform driver to register restart callback.
The implementation of the callback is to issue a pending buffer
written by the application to restart the session when the dequeue
process is stopped due to underrun issue.
The callback is triggered from ALSA core when the framework
detects that the renderer stopped pulling data but the application
is still writing data. It runs in atomic context.

Fixes:
-A disturbance was heard when switching from one song
to the other, or when the song is paused for greater
than 3 seconds and then resumed
-This was due to the previous value of the track
volume being used in the lpa driver
-This was fixed by setting 0 as the initial volume

Change-Id: I035760937d032038fb3f3383dc87ecbdc5f4700d
Signed-off-by: Subhash Chandra Bose Naripeddy <snariped@codeaurora.org>

ASoC: msm: Resume writes only for start command

For compressed and LPA drivers, set pending_buffers flag to 1 only if the client
issues a trigger_start command, not a pause_release command. This flag
is used to initiate writes to the dsp.

Change-Id: I503156863646210b460613a0b9a26a6bfb8854ed
CRs-Fixed: 442269, 449126
Signed-off-by: Haynes Mathew George <hgeorge@codeaurora.org>

ASoC: msm: avoid negative time stamp check

Time stamp is unsigned. There is no need to check for
negative value.

Change-Id: I15e380f81e46908f6a9fe8d29c174de1b7c33173
CRs-fixed: 423372
Signed-off-by: Patrick Lai <plai@codeaurora.org>

ASoC: msm: proper error code for drain ioctl

If a drain ioctl on a compressed driver has been interrupted
by a reset ioctl, we need to return a proper error code for the
drain ioctl

Change-Id: I15f42a22b1cc13b3a0e2ae873adfcd1db2ac1e53
Signed-off-by: Haynes Mathew George <hgeorge@codeaurora.org>
CRs-Fixed: 445370