[alsa-devel] [PATCH v3 2/2] ASoC: rsnd: use dma_sync_single_for_xxx() for IOMMU

[Kuninori Morimoto]

From: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>

IOMMU needs DMA mapping function to use it. One solution is that
we can use DMA mapped dev on snd_pcm_lib_preallocate_pages_for_all()
for SNDRV_DMA_TYPE_DEV. But pcm_new and dma map timing are mismatched.
Thus, this patch uses SNDRV_DMA_TYPE_CONTINUOUS for pcm_new,
and use dma_sync_single_for_xxx() for each transfer.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
---
v1 -> v2 -> v3

 - no change

 sound/soc/sh/rcar/core.c |  4 +--
 sound/soc/sh/rcar/dma.c  | 84 +++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 82 insertions(+), 6 deletions(-)

diff --git a/sound/soc/sh/rcar/core.c b/sound/soc/sh/rcar/core.c
index 9ffa299..912dc62 100644
--- a/sound/soc/sh/rcar/core.c
+++ b/sound/soc/sh/rcar/core.c
@@ -1126,8 +1126,8 @@ static int rsnd_pcm_new(struct snd_soc_pcm_runtime *rtd)
 
 	return snd_pcm_lib_preallocate_pages_for_all(
 		rtd->pcm,
-		SNDRV_DMA_TYPE_DEV,
-		rtd->card->snd_card->dev,
+		SNDRV_DMA_TYPE_CONTINUOUS,
+		snd_dma_continuous_data(GFP_KERNEL),
 		PREALLOC_BUFFER, PREALLOC_BUFFER_MAX);
 }
 
diff --git a/sound/soc/sh/rcar/dma.c b/sound/soc/sh/rcar/dma.c
index 3c663a5..1f405c8 100644
--- a/sound/soc/sh/rcar/dma.c
+++ b/sound/soc/sh/rcar/dma.c
@@ -25,6 +25,10 @@
 
 struct rsnd_dmaen {
 	struct dma_chan		*chan;
+	dma_addr_t		dma_buf;
+	unsigned int		dma_len;
+	unsigned int		dma_period;
+	unsigned int		dma_cnt;
 };
 
 struct rsnd_dmapp {
@@ -58,10 +62,38 @@ struct rsnd_dma_ctrl {
 /*
  *		Audio DMAC
  */
+#define rsnd_dmaen_sync(dmaen, io, i)	__rsnd_dmaen_sync(dmaen, io, i, 1)
+#define rsnd_dmaen_unsync(dmaen, io, i)	__rsnd_dmaen_sync(dmaen, io, i, 0)
+static void __rsnd_dmaen_sync(struct rsnd_dmaen *dmaen, struct rsnd_dai_stream *io,
+			      int i, int sync)
+{
+	struct device *dev = dmaen->chan->device->dev;
+	enum dma_data_direction dir;
+	int is_play = rsnd_io_is_play(io);
+	dma_addr_t buf;
+	int len, max;
+	size_t period;
+
+	len	= dmaen->dma_len;
+	period	= dmaen->dma_period;
+	max	= len / period;
+	i	= i % max;
+	buf	= dmaen->dma_buf + (period * i);
+
+	dir = is_play ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
+
+	if (sync)
+		dma_sync_single_for_device(dev, buf, period, dir);
+	else
+		dma_sync_single_for_cpu(dev, buf, period, dir);
+}
+
 static void __rsnd_dmaen_complete(struct rsnd_mod *mod,
 				  struct rsnd_dai_stream *io)
 {
 	struct rsnd_priv *priv = rsnd_mod_to_priv(mod);
+	struct rsnd_dma *dma = rsnd_mod_to_dma(mod);
+	struct rsnd_dmaen *dmaen = rsnd_dma_to_dmaen(dma);
 	bool elapsed = false;
 	unsigned long flags;
 
@@ -78,9 +110,22 @@ static void __rsnd_dmaen_complete(struct rsnd_mod *mod,
 	 */
 	spin_lock_irqsave(&priv->lock, flags);
 
-	if (rsnd_io_is_working(io))
+	if (rsnd_io_is_working(io)) {
+		rsnd_dmaen_unsync(dmaen, io, dmaen->dma_cnt);
+
+		/*
+		 * Next period is already started.
+		 * Let's sync Next Next period
+		 * see
+		 *	rsnd_dmaen_start()
+		 */
+		rsnd_dmaen_sync(dmaen, io, dmaen->dma_cnt + 2);
+
 		elapsed = rsnd_dai_pointer_update(io, io->byte_per_period);
 
+		dmaen->dma_cnt++;
+	}
+
 	spin_unlock_irqrestore(&priv->lock, flags);
 
 	if (elapsed)
@@ -116,7 +161,12 @@ static int rsnd_dmaen_stop(struct rsnd_mod *mod,
 	struct rsnd_dmaen *dmaen = rsnd_dma_to_dmaen(dma);
 
 	if (dmaen->chan) {
+		int is_play = rsnd_io_is_play(io);
+
 		dmaengine_terminate_all(dmaen->chan);
+		dma_unmap_single(dmaen->chan->device->dev,
+				 dmaen->dma_buf, dmaen->dma_len,
+				 is_play ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
 	}
 
 	return 0;
@@ -184,7 +234,11 @@ static int rsnd_dmaen_start(struct rsnd_mod *mod,
 	struct device *dev = rsnd_priv_to_dev(priv);
 	struct dma_async_tx_descriptor *desc;
 	struct dma_slave_config cfg = {};
+	dma_addr_t buf;
+	size_t len;
+	size_t period;
 	int is_play = rsnd_io_is_play(io);
+	int i;
 	int ret;
 
 	cfg.direction	= is_play ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM;
@@ -201,10 +255,19 @@ static int rsnd_dmaen_start(struct rsnd_mod *mod,
 	if (ret < 0)
 		return ret;
 
+	len	= snd_pcm_lib_buffer_bytes(substream);
+	period	= snd_pcm_lib_period_bytes(substream);
+	buf	= dma_map_single(dmaen->chan->device->dev,
+				 substream->runtime->dma_area,
+				 len,
+				 is_play ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
+	if (dma_mapping_error(dmaen->chan->device->dev, buf)) {
+		dev_err(dev, "dma map failed\n");
+		return -EIO;
+	}
+
 	desc = dmaengine_prep_dma_cyclic(dmaen->chan,
-					 substream->runtime->dma_addr,
-					 snd_pcm_lib_buffer_bytes(substream),
-					 snd_pcm_lib_period_bytes(substream),
+					 buf, len, period,
 					 is_play ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
 					 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 
@@ -216,6 +279,19 @@ static int rsnd_dmaen_start(struct rsnd_mod *mod,
 	desc->callback		= rsnd_dmaen_complete;
 	desc->callback_param	= rsnd_mod_get(dma);
 
+	dmaen->dma_buf		= buf;
+	dmaen->dma_len		= len;
+	dmaen->dma_period	= period;
+	dmaen->dma_cnt		= 0;
+
+	/*
+	 * synchronize this and next period
+	 * see
+	 *	__rsnd_dmaen_complete()
+	 */
+	for (i = 0; i < 2; i++)
+		rsnd_dmaen_sync(dmaen, io, i);
+
 	if (dmaengine_submit(desc) < 0) {
 		dev_err(dev, "dmaengine_submit() fail\n");
 		return -EIO;
-- 
2.7.4