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pcm: dmix: Add option to allow alignment of slave pointers

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These changes are required due to the kernel
commit 07b7acb51d283d8469696c906b91f1882696a4d4
("ASoC: rsnd: update pointer more accurate")

Issue is that snd_pcm_wait() goes back to waiting because the hw_ptr
is not period aligned. Therefore snd_pcm_wait() will block for a longer
time as required.

With these rcar driver changes the exact position of the dma is returned.
During snd_pcm_start they read hw_ptr as reference, and this hw_ptr
is now not period aligned, and is a little ahead over the period while it
is read. Therefore when the avail is calculated during snd_pcm_wait(),
it is missing the avail_min by a few frames.

An additional option hw_ptr_alignment is provided to dmix configuration,
to allow the user to configure the slave application and hw pointer
alignment at startup

[ Slight indentation and parentheses removals by tiwai ]

Signed-off-by: Laxmi Devi <Laxmi.Devi@in.bosch.com>
Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Laxmi Devi 2018-11-13 08:43:00 +01:00 • committed by Takashi Iwai
parent 178fe66bc8
commit 6b058fda9d
3 changed files with 76 additions and 8 deletions
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9
src/pcm/pcm_direct.h
View file

@ -50,6 +50,13 @@ typedef void (mix_areas_u8_t)(unsigned int size,
volatile signed int *sum, size_t dst_step,
size_t src_step, size_t sum_step);
typedef enum snd_pcm_direct_hw_ptr_alignment {
SND_PCM_HW_PTR_ALIGNMENT_NO = 0, /* use the hw_ptr as is and do no rounding */
SND_PCM_HW_PTR_ALIGNMENT_ROUNDUP = 1, /* round the slave_appl_ptr up to slave_period */
SND_PCM_HW_PTR_ALIGNMENT_ROUNDDOWN = 2, /* round slave_hw_ptr and slave_appl_ptr down to slave_period */
SND_PCM_HW_PTR_ALIGNMENT_AUTO = 3 /* automatic selection */
} snd_pcm_direct_hw_ptr_alignment_t;
struct slave_params {
snd_pcm_format_t format;
int rate;
@ -160,6 +167,7 @@ struct snd_pcm_direct {
unsigned int *bindings;
unsigned int recoveries; /* mirror of executed recoveries on slave */
int direct_memory_access; /* use arch-optimized buffer RW */
snd_pcm_direct_hw_ptr_alignment_t hw_ptr_alignment;
union {
struct {
int shmid_sum; /* IPC global sum ring buffer memory identification */
@ -342,6 +350,7 @@ struct snd_pcm_direct_open_conf {
int max_periods;
int var_periodsize;
int direct_memory_access;
snd_pcm_direct_hw_ptr_alignment_t hw_ptr_alignment;
snd_config_t *slave;
snd_config_t *bindings;
};