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Commit 43a3cec0 authored by Sascha Hauer's avatar Sascha Hauer Committed by Mark Brown
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ASoC: imx-ssi: Use a hrtimer in FIQ mode 



Using a regular timer results in poll times < 1 jiffie with small
buffers, so we loaded the timer with the actual jiffie value. We can
be more accurate using a hrtimer. Also, we have to call
snd_pcm_period_elapsed after playing period_bytes and not
runtime->period_size (which is in samples and not in bytes).

Signed-off-by: default avatarSascha Hauer <s.hauer@pengutronix.de>
Acked-by: default avatarLiam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
parent 671999cb

sound/soc/imx/imx-pcm-fiq.c

+21 −24
Original line number Diff line number Diff line
@@ -38,20 +38,17 @@ struct imx_pcm_runtime_data { 
	unsigned long offset;

	unsigned long last_offset;

	unsigned long size;

	struct timer_list timer;

	int poll_time;

	struct hrtimer hrt;

	int poll_time_ns;

	struct snd_pcm_substream *substream;

};



static inline void imx_ssi_set_next_poll(struct imx_pcm_runtime_data *iprtd)

static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)

{

	iprtd->timer.expires = jiffies + iprtd->poll_time;

}



static void imx_ssi_timer_callback(unsigned long data)

{

	struct snd_pcm_substream *substream = (void *)data;

	struct imx_pcm_runtime_data *iprtd =

		container_of(hrt, struct imx_pcm_runtime_data, hrt);

	struct snd_pcm_substream *substream = iprtd->substream;

	struct snd_pcm_runtime *runtime = substream->runtime;

	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

	struct pt_regs regs;

	unsigned long delta;
@@ -71,16 +68,14 @@ static void imx_ssi_timer_callback(unsigned long data) 


	/* If we've transferred at least a period then report it and

	 * reset our poll time */

	if (delta >= runtime->period_size) {

	if (delta >= iprtd->period) {

		snd_pcm_period_elapsed(substream);

		iprtd->last_offset = iprtd->offset;



		imx_ssi_set_next_poll(iprtd);

	}



	/* Restart the timer; if we didn't report we'll run on the next tick */

	add_timer(&iprtd->timer);

	hrtimer_forward_now(hrt, ns_to_ktime(iprtd->poll_time_ns));



	return HRTIMER_RESTART;

}



static struct fiq_handler fh = {
@@ -98,8 +93,8 @@ static int snd_imx_pcm_hw_params(struct snd_pcm_substream *substream, 
	iprtd->period = params_period_bytes(params) ;

	iprtd->offset = 0;

	iprtd->last_offset = 0;

	iprtd->poll_time = HZ / (params_rate(params) / params_period_size(params));



	iprtd->poll_time_ns = 1000000000 / params_rate(params) *

				params_period_size(params);

	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);



	return 0;
@@ -134,8 +129,8 @@ static int snd_imx_pcm_trigger(struct snd_pcm_substream *substream, int cmd) 
	case SNDRV_PCM_TRIGGER_START:

	case SNDRV_PCM_TRIGGER_RESUME:

	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:

		imx_ssi_set_next_poll(iprtd);

		add_timer(&iprtd->timer);

		hrtimer_start(&iprtd->hrt, ns_to_ktime(iprtd->poll_time_ns),

		      HRTIMER_MODE_REL);

		if (++fiq_enable == 1)

			enable_fiq(imx_pcm_fiq);
@@ -144,7 +139,7 @@ static int snd_imx_pcm_trigger(struct snd_pcm_substream *substream, int cmd) 
	case SNDRV_PCM_TRIGGER_STOP:

	case SNDRV_PCM_TRIGGER_SUSPEND:

	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:

		del_timer(&iprtd->timer);

		hrtimer_cancel(&iprtd->hrt);

		if (--fiq_enable == 0)

			disable_fiq(imx_pcm_fiq);
@@ -193,9 +188,10 @@ static int snd_imx_open(struct snd_pcm_substream *substream) 
	iprtd = kzalloc(sizeof(*iprtd), GFP_KERNEL);

	runtime->private_data = iprtd;



	init_timer(&iprtd->timer);

	iprtd->timer.data = (unsigned long)substream;

	iprtd->timer.function = imx_ssi_timer_callback;

	iprtd->substream = substream;



	hrtimer_init(&iprtd->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);

	iprtd->hrt.function = snd_hrtimer_callback;



	ret = snd_pcm_hw_constraint_integer(substream->runtime,

			SNDRV_PCM_HW_PARAM_PERIODS);
@@ -211,7 +207,8 @@ static int snd_imx_close(struct snd_pcm_substream *substream) 
	struct snd_pcm_runtime *runtime = substream->runtime;

	struct imx_pcm_runtime_data *iprtd = runtime->private_data;



	del_timer_sync(&iprtd->timer);

	hrtimer_cancel(&iprtd->hrt);



	kfree(iprtd);



	return 0;