Revise the PCM callback system after adding multichannel audio.

Additional status callback is added to pcm_play/rec_data instead of
using a special function to set it. Status includes DMA error
reporting to the status callback. Playback and recording callback
become more alike except playback uses "const void **addr" (because
the data should not be altered) and recording  uses "void **addr".
"const" is put in place throughout where appropriate.

Most changes are fairly trivial. One that should be checked in
particular because it isn't so much is telechips, if anyone cares to
bother. PP5002 is not so trivial either but that tested as working.

Change-Id: I4928d69b3b3be7fb93e259f81635232df9bd1df2
Reviewed-on: http://gerrit.rockbox.org/166
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Tested-by: Michael Sevakis <jethead71@rockbox.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/apps/plugins/fft/fft.c b/apps/plugins/fft/fft.c
index 1c4e1b4c20..f7d8943576 100644
--- a/apps/plugins/fft/fft.c
+++ b/apps/plugins/fft/fft.c
@@ -1186,8 +1186,8 @@ static inline bool fft_init_fft_lib(void)
 static inline bool fft_get_fft(void)
 {
     int count;
-    int16_t *value =
-        (int16_t *) rb->mixer_channel_get_buffer(PCM_MIXER_CHAN_PLAYBACK, &count);
+    const int16_t *value =
+        rb->mixer_channel_get_buffer(PCM_MIXER_CHAN_PLAYBACK, &count);
     /* This block can introduce discontinuities in our data. Meaning, the
      * FFT will not be done a continuous segment of the signal. Which can
      * be bad. Or not.