[alsa-devel] [PATCH 13/15] ASoC: SND_S3C_DMA_LEGACY needs S3C24XX_DMA

Arnd Bergmann arnd at arndb.de
Fri May 2 00:35:21 CEST 2014


On Thursday 01 May 2014 12:11:25 Mark Brown wrote:
> On Tue, Apr 29, 2014 at 07:18:34PM +0800, Xia Kaixu wrote:
> > From: Arnd Bergmann <arnd at arndb.de>
> > 
> > SND_S3C_DMA_LEGACY can only be set on S3C24xx, which does not
> > (yet) support the dmaengine framework, so samsung_dma_get_ops()
> > fails to link if S3C24XX_DMA is disabled:
> 
> Why is the fix for this not to ensure that s3c24xx always enables the
> DMA controller - how likely is it that it would be sane to build a
> kernel without DMA after all?

S3C24XX_DMA is only needed for ASoC and for s3cmci. The latter
uses 'depends on S3C24XX_DMA'. arch/arm/configs/tct_hammer_defconfig
is an example of a configuration that does not include DMA because
it uses neither of the two drivers.

On a related topic, I looked at the overall DMA situation for
plat-samsung again now, and it looks much nicer now than it used to,
with mach-s3c64xx fully migrated to dmaengine, so there might be an
even better way to deal with this.

>From all I can tell, sound/soc/samsung is the only remaining user
of the plat/dma.h interfaces, and there is only one other  driver
using the s3c24xx_dma interface directly, drivers/mmc/host/s3cmci.c.

How about the patch below?
8<-------
ASoC: s3c24xx: use legacy DMA interface directly

The samsung platform code has a wrapper around the legacy s3c24xx
DMA API as an alternative to the dmaengine API. This is only used
by the legacy s3c24xx sound support, which is never used in combination
with the dmaengine API.

We can simplify the ASoC code significantly, and thereby completely
obsoleting arch/arm/plat-samsung/dma-ops.c,
arch/arm/plat-samsung/s3c-dma-ops.c and
arch/arm/plat-samsung/include/plat/dma-ops.h.

This patch achieves this by open-coding the implementation of this
wrapper, which ends up saving us more code than we have to add.
s3c24xx does not support cyclic DMA, so anything referring to that
gets deleted in the process.

The plat-samsung dma wrapper code is now dead code and can be removed
subsequently.

Signed-off--by: Arnd Bergmann <arnd at arndb.de>
---

 sound/soc/samsung/ac97.c | 10 ++----
 sound/soc/samsung/dma.c  | 79 +++++++++++++++---------------------------------
 sound/soc/samsung/dma.h  |  2 --
 3 files changed, 27 insertions(+), 64 deletions(-)

diff --git a/sound/soc/samsung/ac97.c b/sound/soc/samsung/ac97.c
index 76b072b..28fe097 100644
--- a/sound/soc/samsung/ac97.c
+++ b/sound/soc/samsung/ac97.c
@@ -253,10 +253,7 @@ static int s3c_ac97_trigger(struct snd_pcm_substream *substream, int cmd,
 
 	writel(ac_glbctrl, s3c_ac97.regs + S3C_AC97_GLBCTRL);
 
-	if (!dma_data->ops)
-		dma_data->ops = samsung_dma_get_ops();
-
-	dma_data->ops->started(dma_data->channel);
+	s3c2410_dma_ctrl(dma_data->channel, S3C2410_DMAOP_STARTED);
 
 	return 0;
 }
@@ -287,10 +284,7 @@ static int s3c_ac97_mic_trigger(struct snd_pcm_substream *substream,
 
 	writel(ac_glbctrl, s3c_ac97.regs + S3C_AC97_GLBCTRL);
 
-	if (!dma_data->ops)
-		dma_data->ops = samsung_dma_get_ops();
-
-	dma_data->ops->started(dma_data->channel);
+	s3c2410_dma_ctrl(dma_data->channel, S3C2410_DMAOP_STARTED);
 
 	return 0;
 }
diff --git a/sound/soc/samsung/dma.c b/sound/soc/samsung/dma.c
index dc09b71..3c6e2f2 100644
--- a/sound/soc/samsung/dma.c
+++ b/sound/soc/samsung/dma.c
@@ -54,8 +54,6 @@ struct runtime_data {
 	struct s3c_dma_params *params;
 };
 
-static void audio_buffdone(void *data);
-
 /* dma_enqueue
  *
  * place a dma buffer onto the queue for the dma system
@@ -66,7 +64,6 @@ static void dma_enqueue(struct snd_pcm_substream *substream)
 	struct runtime_data *prtd = substream->runtime->private_data;
 	dma_addr_t pos = prtd->dma_pos;
 	unsigned int limit;
-	struct samsung_dma_prep dma_info;
 
 	pr_debug("Entered %s\n", __func__);
 
@@ -75,33 +72,11 @@ static void dma_enqueue(struct snd_pcm_substream *substream)
 	pr_debug("%s: loaded %d, limit %d\n",
 				__func__, prtd->dma_loaded, limit);
 
-	dma_info.cap = (samsung_dma_has_circular() ? DMA_CYCLIC : DMA_SLAVE);
-	dma_info.direction =
-		(substream->stream == SNDRV_PCM_STREAM_PLAYBACK
-		? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM);
-	dma_info.fp = audio_buffdone;
-	dma_info.fp_param = substream;
-	dma_info.period = prtd->dma_period;
-	dma_info.len = prtd->dma_period*limit;
-
-	if (dma_info.cap == DMA_CYCLIC) {
-		dma_info.buf = pos;
-		prtd->params->ops->prepare(prtd->params->ch, &dma_info);
-		prtd->dma_loaded += limit;
-		return;
-	}
-
 	while (prtd->dma_loaded < limit) {
 		pr_debug("dma_loaded: %d\n", prtd->dma_loaded);
 
-		if ((pos + dma_info.period) > prtd->dma_end) {
-			dma_info.period  = prtd->dma_end - pos;
-			pr_debug("%s: corrected dma len %ld\n",
-					__func__, dma_info.period);
-		}
-
-		dma_info.buf = pos;
-		prtd->params->ops->prepare(prtd->params->ch, &dma_info);
+		s3c2410_dma_enqueue(prtd->params->channel, substream, pos,
+				    prtd->dma_period * limit);
 
 		prtd->dma_loaded++;
 		pos += prtd->dma_period;
@@ -112,7 +87,8 @@ static void dma_enqueue(struct snd_pcm_substream *substream)
 	prtd->dma_pos = pos;
 }
 
-static void audio_buffdone(void *data)
+static void audio_buffdone(struct s3c2410_dma_chan *channel, void *data,
+		       int size, enum s3c2410_dma_buffresult res)
 {
 	struct snd_pcm_substream *substream = data;
 	struct runtime_data *prtd = substream->runtime->private_data;
@@ -128,10 +104,8 @@ static void audio_buffdone(void *data)
 			snd_pcm_period_elapsed(substream);
 
 		spin_lock(&prtd->lock);
-		if (!samsung_dma_has_circular()) {
-			prtd->dma_loaded--;
-			dma_enqueue(substream);
-		}
+		prtd->dma_loaded--;
+		dma_enqueue(substream);
 		spin_unlock(&prtd->lock);
 	}
 }
@@ -145,8 +119,7 @@ static int dma_hw_params(struct snd_pcm_substream *substream,
 	unsigned long totbytes = params_buffer_bytes(params);
 	struct s3c_dma_params *dma =
 		snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
-	struct samsung_dma_req req;
-	struct samsung_dma_config config;
+	enum dma_transfer_direction direction;
 
 	pr_debug("Entered %s\n", __func__);
 
@@ -164,24 +137,22 @@ static int dma_hw_params(struct snd_pcm_substream *substream,
 		pr_debug("params %p, client %p, channel %d\n", prtd->params,
 			prtd->params->client, prtd->params->channel);
 
-		prtd->params->ops = samsung_dma_get_ops();
-
-		req.cap = (samsung_dma_has_circular() ?
-			DMA_CYCLIC : DMA_SLAVE);
-		req.client = prtd->params->client;
-		config.direction =
-			(substream->stream == SNDRV_PCM_STREAM_PLAYBACK
+		direction = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK
 			? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM);
-		config.width = prtd->params->dma_size;
-		config.fifo = prtd->params->dma_addr;
-		prtd->params->ch = prtd->params->ops->request(
-				prtd->params->channel, &req, rtd->cpu_dai->dev,
-				prtd->params->ch_name);
-		if (!prtd->params->ch) {
+
+		if (s3c2410_dma_request(prtd->params->channel,
+					(void*)prtd->params->client, NULL) < 0) {
 			pr_err("Failed to allocate DMA channel\n");
+			s3c2410_dma_free(prtd->params->channel,
+					 (void*)prtd->params->client);
 			return -ENXIO;
 		}
-		prtd->params->ops->config(prtd->params->ch, &config);
+		s3c2410_dma_devconfig(prtd->params->channel, direction,
+				      prtd->params->dma_addr);
+		s3c2410_dma_config(prtd->params->channel,
+				   prtd->params->dma_size);
+		s3c2410_dma_set_buffdone_fn(prtd->params->channel,
+					    audio_buffdone);
 	}
 
 	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
@@ -208,9 +179,9 @@ static int dma_hw_free(struct snd_pcm_substream *substream)
 	snd_pcm_set_runtime_buffer(substream, NULL);
 
 	if (prtd->params) {
-		prtd->params->ops->flush(prtd->params->ch);
-		prtd->params->ops->release(prtd->params->ch,
-					prtd->params->client);
+		s3c2410_dma_ctrl(prtd->params->channel, S3C2410_DMAOP_FLUSH);
+		s3c2410_dma_free(prtd->params->channel,
+				 (void*)prtd->params->client);
 		prtd->params = NULL;
 	}
 
@@ -230,7 +201,7 @@ static int dma_prepare(struct snd_pcm_substream *substream)
 		return 0;
 
 	/* flush the DMA channel */
-	prtd->params->ops->flush(prtd->params->ch);
+	s3c2410_dma_ctrl(prtd->params->channel, S3C2410_DMAOP_FLUSH);
 
 	prtd->dma_loaded = 0;
 	prtd->dma_pos = prtd->dma_start;
@@ -253,12 +224,12 @@ static int dma_trigger(struct snd_pcm_substream *substream, int cmd)
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 		prtd->state |= ST_RUNNING;
-		prtd->params->ops->trigger(prtd->params->ch);
+		s3c2410_dma_ctrl(prtd->params->channel, S3C2410_DMAOP_START);
 		break;
 
 	case SNDRV_PCM_TRIGGER_STOP:
 		prtd->state &= ~ST_RUNNING;
-		prtd->params->ops->stop(prtd->params->ch);
+		s3c2410_dma_ctrl(prtd->params->channel, S3C2410_DMAOP_STOP);
 		break;
 
 	default:
diff --git a/sound/soc/samsung/dma.h b/sound/soc/samsung/dma.h
index ad7c0f0..c52fa86 100644
--- a/sound/soc/samsung/dma.h
+++ b/sound/soc/samsung/dma.h
@@ -23,8 +23,6 @@ struct s3c_dma_params {
 	int channel;				/* Channel ID */
 	dma_addr_t dma_addr;
 	int dma_size;			/* Size of the DMA transfer */
-	unsigned ch;
-	struct samsung_dma_ops *ops;
 	char *ch_name;
 	struct snd_dmaengine_dai_dma_data dma_data;
 };



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