From: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com
Front sound driver has no real interrupts, so playback/capture period passed interrupt needs to be emulated: this is done via timer. Add required timer operations, this is based on sound/drivers/dummy.c.
Signed-off-by: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com --- sound/drivers/xen-front.c | 121 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 121 insertions(+)
diff --git a/sound/drivers/xen-front.c b/sound/drivers/xen-front.c index 9f31e6832086..507c5eb343c8 100644 --- a/sound/drivers/xen-front.c +++ b/sound/drivers/xen-front.c @@ -67,12 +67,29 @@ struct sh_buf_info { size_t vbuffer_sz; };
+struct sdev_alsa_timer_info { + spinlock_t lock; + struct timer_list timer; + unsigned long base_time; + /* fractional sample position (based HZ) */ + unsigned int frac_pos; + unsigned int frac_period_rest; + /* buffer_size * HZ */ + unsigned int frac_buffer_size; + /* period_size * HZ */ + unsigned int frac_period_size; + unsigned int rate; + int elapsed; + struct snd_pcm_substream *substream; +}; + struct sdev_pcm_stream_info { int unique_id; struct snd_pcm_hardware pcm_hw; struct xdrv_evtchnl_info *evt_chnl; bool is_open; uint8_t req_next_id; + struct sdev_alsa_timer_info timer; struct sh_buf_info sh_buf; };
@@ -148,6 +165,110 @@ static struct sdev_pcm_stream_info *sdrv_stream_get( return stream; }
+static inline void sdrv_alsa_timer_rearm(struct sdev_alsa_timer_info *dpcm) +{ + mod_timer(&dpcm->timer, jiffies + + (dpcm->frac_period_rest + dpcm->rate - 1) / dpcm->rate); +} + +static void sdrv_alsa_timer_update(struct sdev_alsa_timer_info *dpcm) +{ + unsigned long delta; + + delta = jiffies - dpcm->base_time; + if (!delta) + return; + dpcm->base_time += delta; + delta *= dpcm->rate; + dpcm->frac_pos += delta; + while (dpcm->frac_pos >= dpcm->frac_buffer_size) + dpcm->frac_pos -= dpcm->frac_buffer_size; + while (dpcm->frac_period_rest <= delta) { + dpcm->elapsed++; + dpcm->frac_period_rest += dpcm->frac_period_size; + } + dpcm->frac_period_rest -= delta; +} + +static int sdrv_alsa_timer_start(struct snd_pcm_substream *substream) +{ + struct sdev_pcm_stream_info *stream = sdrv_stream_get(substream); + struct sdev_alsa_timer_info *dpcm = &stream->timer; + + spin_lock(&dpcm->lock); + dpcm->base_time = jiffies; + sdrv_alsa_timer_rearm(dpcm); + spin_unlock(&dpcm->lock); + return 0; +} + +static int sdrv_alsa_timer_stop(struct snd_pcm_substream *substream) +{ + struct sdev_pcm_stream_info *stream = sdrv_stream_get(substream); + struct sdev_alsa_timer_info *dpcm = &stream->timer; + + spin_lock(&dpcm->lock); + del_timer(&dpcm->timer); + spin_unlock(&dpcm->lock); + return 0; +} + +static int sdrv_alsa_timer_prepare(struct snd_pcm_substream *substream) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + struct sdev_pcm_stream_info *stream = sdrv_stream_get(substream); + struct sdev_alsa_timer_info *dpcm = &stream->timer; + + dpcm->frac_pos = 0; + dpcm->rate = runtime->rate; + dpcm->frac_buffer_size = runtime->buffer_size * HZ; + dpcm->frac_period_size = runtime->period_size * HZ; + dpcm->frac_period_rest = dpcm->frac_period_size; + dpcm->elapsed = 0; + return 0; +} + +static void sdrv_alsa_timer_callback(unsigned long data) +{ + struct sdev_alsa_timer_info *dpcm = (struct sdev_alsa_timer_info *)data; + int elapsed; + + spin_lock(&dpcm->lock); + sdrv_alsa_timer_update(dpcm); + sdrv_alsa_timer_rearm(dpcm); + elapsed = dpcm->elapsed; + dpcm->elapsed = 0; + spin_unlock(&dpcm->lock); + if (elapsed) + snd_pcm_period_elapsed(dpcm->substream); +} + +static snd_pcm_uframes_t sdrv_alsa_timer_pointer( + struct snd_pcm_substream *substream) +{ + struct sdev_pcm_stream_info *stream = sdrv_stream_get(substream); + struct sdev_alsa_timer_info *dpcm = &stream->timer; + snd_pcm_uframes_t pos; + + spin_lock(&dpcm->lock); + sdrv_alsa_timer_update(dpcm); + pos = dpcm->frac_pos / HZ; + spin_unlock(&dpcm->lock); + return pos; +} + +static int sdrv_alsa_timer_create(struct snd_pcm_substream *substream) +{ + struct sdev_pcm_stream_info *stream = sdrv_stream_get(substream); + struct sdev_alsa_timer_info *dpcm = &stream->timer; + + spin_lock_init(&dpcm->lock); + dpcm->substream = substream; + setup_timer(&dpcm->timer, sdrv_alsa_timer_callback, + (unsigned long) dpcm); + return 0; +} + static void sdrv_copy_pcm_hw(struct snd_pcm_hardware *dst, struct snd_pcm_hardware *src, struct snd_pcm_hardware *ref_pcm_hw)