Add three alsa controls to expose selection of playback
device, capture device and call mode.Alsa kernel will
route pcm data to the selected output/input port.

bug 771510

Change-Id: Ibdeebbd799b2ae36046a77327ec8b6a3b01553a9
Reviewed-on: http://git-master/r/14729
Tested-by: Sumit Bhattacharya <sumitb@nvidia.com>
Reviewed-by: Sachin Nikam <snikam@nvidia.com>
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>

- Refactor DMA interactions to handle continuous single-buffered DMA
- Remove PIO support (obsolete, conflicts with new buffer management)
- Remove sample rate conversion (obsolete)
- Remove error-reporting logic
- Remove TEGRA_AUDIO_IN/OUT_GET/SET_BUF_CONFIG
- Add TEGRA_AUDIO_IN/OUT_GET/SET_NUM_BUFS

Change-Id: I8f21a0bb314aac3b7d1bb4918bda9141e58db38d
Signed-off-by: Iliyan Malchev <malchev@google.com>

-- Ignore kfifo thresholds on recording and playback and adjust the delays.
-- Take out the code from TEGRA_AUDIO_IN_STOP into a separate function
   stop_recording_nosync()
-- Rename stop_recording() to wait_for_recording_to_stop().
-- add ioctl(TEGRA_AUDIO_OUT_FLUSH), which blocks the caller until the output
   fifo is drained.  While the caller is blocked, pending write() calls will
   return immediately with whatever data they had managed to queue up.
-- removed ioctl(TEGRA_AUDIO_OUT_PRELOAD_FIFO)
-- since TEGRA_AUDIO_OUT_FLUSH and TEGRA_AUDIO_IN_STOP act similarly, moved
   audio_driver_state::recording_cancelled to audio_stream::stop and changed
   the code accordingly.  Renamed functions wait_for_recording_to_stop() and
   stop_recording_nosync() to wait_till_stopped() and request_stop_nosync()
   since they handle both playback and recording.
-- print errors on close() if wakelocks are still held
-- Call request_stop_nosync() on close() of a recording file handle
-- Do not use struct audio_stream::active for playback streams.  Instead,
   where applicable, use kfifo_len().  As a consequence, playback kfifo
   underruns are no longer reported.  These were bogus anyway, as we really
   need the DMA engine to tell us if there are underruns.
-- Because of above item, had to rework tx_fifo_atn_store(),
   rx_fifo_atn_store(), and __attr_fifo_atn_write().
-- Set struct audio_stream::active for a recording stream to true when a
   recording starts, and set it to false when recording get stopped.  Do not
   set/clear it within the body of read(), because just being within read()
   does not mean that recording is in progress.
-- In tegra_audio_read(), check for stop == true before calling
   start_recording_if_necessary(); this makes sure that if a user calls read()
   after calling ioctl(TEGRA_AUDIO_IN_STOP), recording will not resume unless
   ioctl(TEGRA_AUDIO_IN_START) gets called, or the file is closed and
   re-opened.
-- Fixed TEGRA_AUDIO_IN_START
-- In PIO mode, enabled FIFOs before enabling interrupts as specified in the
   TRM.
-- Added missing break in tegra_audio_ioctl().
-- Silenced some debug spew

Signed-off-by: Iliyan Malchev <malchev@google.com>

Added an ioctl to set the bit format for I2S between "DSP"/"PCM" mode and
normal mode (set by board file)

Signed-off-by: Iliyan Malchev <malchev@google.com>

This patch replaces the error counter with two separate error counters, one for
late dma callbacks, and another for overruns (during recording) or underruns
(during playback).  The ioctls TEGRA_AUDIO_IN_GET_ERROR_COUNT and
TEGRA_AUDIO_OUT_GET_ERROR_COUNT now take a pointer to a struct containing both
error counters.

Signed-off-by: Iliyan Malchev <malchev@google.com>

Add an ioctl to allow the TX fifo to be loaded with data before playback
starts.  Playback can then be started by calling write() on the FIFO, even
with a length of 0.  This will cause the pending data to be played out.

Signed-off-by: Iliyan Malchev <malchev@google.com>

-- Use consistently the various state flags:
   -- active is set only when there is a read or write in flight
   -- recording_canncelled is set only when recording is stopped via the ioctl()
   -- dma_has_it is used to determine whether DMA is already in flight; do not
      use the state of the fifos for this (e.g., if the TX fifo is empty, do not
      assume that playback is stopped)
   -- added a stop_completion (implemented for readers only) so that readers
      closing a stream can wait until DMA or PIO transactions are stopped
-- Split /dev/audio0_{in,out} into /dev/audio0_{in,in_ctl,out,out_ctl} where the
   _ctl versions have the ioctl()s
-- Introduced an error count per audio_stream; error count is reset on open, can
   be read back & reset through an ioctl

Signed-off-by: Iliyan Malchev <malchev@google.com>

-- Add ioctls for configuring buffer, threshold, and DMA-transaction sizes from
   user space.
-- Buffer sizes are provided in orders of magnitude.
-- Allocate max-sized buffers during probe, and allow the user to resize them
   only within the original allocation, to avoid the risk from kmalloc failing
   due to kernel-heap fragmentation, and also to avoid race conditions on DMA
   shut-down.
-- In tegra_audio_write(), moved the call to start_playback_if_necessary()
   immediately after writing to the fifo.  Otherwise, when the fifo size is
   smaller than what the user is trying to write, the user will block before
   playback is started.
-- Silenced printk spew on spinning on i2s registers after transactions are
   completed.
-- Cleaned up a 80-col style violation in downsample()

Signed-off-by: Iliyan Malchev <malchev@google.com>

downsampling:
-- add ioctl()s to downsample recorded data
-- supported frequencies are 8kHz, 11.025kHz, 22.05kHz, and 44.1kHz
-- downsamping to stereo and mono
-- default is 11.025kHz mono

fixes:
-- fix crashes from dequeuing DMA requests twice

Signed-off-by: Iliyan Malchev <malchev@google.com>

-- add audio_in_stream (identical to audio_out_stream, may merge them later)
-- add support for DMA and PIO recording
-- add ioctls for /dev/audio<n>_in to start and stop recording

Signed-off-by: Iliyan Malchev <malchev@google.com>