ASoC: rsnd: add common DMAEngine method

R-Car Sound driver will support DMA transfer in the future,
then, SSI/SRU/SRC will use it.
Current R-Car can't use soc-dmaengine-pcm.c since its DMAEngine
doesn't support dmaengine_prep_dma_cyclic(),
and SSI needs double plane transfer (which needs special submit) on DMAC.
This patch adds common DMAEngine method for it

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/sh/rcar/core.c

@@ -173,6 +173,138 @@ void rsnd_mod_init(struct rsnd_priv *priv,
 	INIT_LIST_HEAD(&mod->list);
 }
 
+/*
+ *	rsnd_dma functions
+ */
+static void rsnd_dma_continue(struct rsnd_dma *dma)
+{
+	/* push next A or B plane */
+	dma->submit_loop = 1;
+	schedule_work(&dma->work);
+}
+
+void rsnd_dma_start(struct rsnd_dma *dma)
+{
+	/* push both A and B plane*/
+	dma->submit_loop = 2;
+	schedule_work(&dma->work);
+}
+
+void rsnd_dma_stop(struct rsnd_dma *dma)
+{
+	dma->submit_loop = 0;
+	cancel_work_sync(&dma->work);
+	dmaengine_terminate_all(dma->chan);
+}
+
+static void rsnd_dma_complete(void *data)
+{
+	struct rsnd_dma *dma = (struct rsnd_dma *)data;
+	struct rsnd_priv *priv = dma->priv;
+	unsigned long flags;
+
+	rsnd_lock(priv, flags);
+
+	dma->complete(dma);
+
+	if (dma->submit_loop)
+		rsnd_dma_continue(dma);
+
+	rsnd_unlock(priv, flags);
+}
+
+static void rsnd_dma_do_work(struct work_struct *work)
+{
+	struct rsnd_dma *dma = container_of(work, struct rsnd_dma, work);
+	struct rsnd_priv *priv = dma->priv;
+	struct device *dev = rsnd_priv_to_dev(priv);
+	struct dma_async_tx_descriptor *desc;
+	dma_addr_t buf;
+	size_t len;
+	int i;
+
+	for (i = 0; i < dma->submit_loop; i++) {
+
+		if (dma->inquiry(dma, &buf, &len) < 0)
+			return;
+
+		desc = dmaengine_prep_slave_single(
+			dma->chan, buf, len, dma->dir,
+			DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+		if (!desc) {
+			dev_err(dev, "dmaengine_prep_slave_sg() fail\n");
+			return;
+		}
+
+		desc->callback		= rsnd_dma_complete;
+		desc->callback_param	= dma;
+
+		if (dmaengine_submit(desc) < 0) {
+			dev_err(dev, "dmaengine_submit() fail\n");
+			return;
+		}
+
+	}
+
+	dma_async_issue_pending(dma->chan);
+}
+
+int rsnd_dma_available(struct rsnd_dma *dma)
+{
+	return !!dma->chan;
+}
+
+static bool rsnd_dma_filter(struct dma_chan *chan, void *param)
+{
+	chan->private = param;
+
+	return true;
+}
+
+int rsnd_dma_init(struct rsnd_priv *priv, struct rsnd_dma *dma,
+		  int is_play, int id,
+		  int (*inquiry)(struct rsnd_dma *dma,
+				  dma_addr_t *buf, int *len),
+		  int (*complete)(struct rsnd_dma *dma))
+{
+	struct device *dev = rsnd_priv_to_dev(priv);
+	dma_cap_mask_t mask;
+
+	if (dma->chan) {
+		dev_err(dev, "it already has dma channel\n");
+		return -EIO;
+	}
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+
+	dma->slave.shdma_slave.slave_id = id;
+
+	dma->chan = dma_request_channel(mask, rsnd_dma_filter,
+					&dma->slave.shdma_slave);
+	if (!dma->chan) {
+		dev_err(dev, "can't get dma channel\n");
+		return -EIO;
+	}
+
+	dma->dir = is_play ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
+	dma->priv = priv;
+	dma->inquiry = inquiry;
+	dma->complete = complete;
+	INIT_WORK(&dma->work, rsnd_dma_do_work);
+
+	return 0;
+}
+
+void  rsnd_dma_quit(struct rsnd_priv *priv,
+		    struct rsnd_dma *dma)
+{
+	if (dma->chan)
+		dma_release_channel(dma->chan);
+
+	dma->chan = NULL;
+}
+
 /*
  *	rsnd_dai functions
  */

sound/soc/sh/rcar/rsnd.h

@@ -13,9 +13,12 @@
 
 #include <linux/clk.h>
 #include <linux/device.h>
+#include <linux/dma-mapping.h>
 #include <linux/io.h>
 #include <linux/list.h>
 #include <linux/module.h>
+#include <linux/sh_dma.h>
+#include <linux/workqueue.h>
 #include <sound/rcar_snd.h>
 #include <sound/soc.h>
 #include <sound/pcm_params.h>
@@ -78,6 +81,32 @@ void rsnd_write(struct rsnd_priv *priv, struct rsnd_mod *mod,
 void rsnd_bset(struct rsnd_priv *priv, struct rsnd_mod *mod, enum rsnd_reg reg,
 		    u32 mask, u32 data);
 
+/*
+ *	R-Car DMA
+ */
+struct rsnd_dma {
+	struct rsnd_priv	*priv;
+	struct sh_dmae_slave	slave;
+	struct work_struct	work;
+	struct dma_chan		*chan;
+	enum dma_data_direction dir;
+	int (*inquiry)(struct rsnd_dma *dma, dma_addr_t *buf, int *len);
+	int (*complete)(struct rsnd_dma *dma);
+
+	int submit_loop;
+};
+
+void rsnd_dma_start(struct rsnd_dma *dma);
+void rsnd_dma_stop(struct rsnd_dma *dma);
+int rsnd_dma_available(struct rsnd_dma *dma);
+int rsnd_dma_init(struct rsnd_priv *priv, struct rsnd_dma *dma,
+	int is_play, int id,
+	int (*inquiry)(struct rsnd_dma *dma, dma_addr_t *buf, int *len),
+	int (*complete)(struct rsnd_dma *dma));
+void  rsnd_dma_quit(struct rsnd_priv *priv,
+		    struct rsnd_dma *dma);
+
+
 /*
  *	R-Car sound mod
  */
@@ -103,9 +132,12 @@ struct rsnd_mod {
 	struct rsnd_priv *priv;
 	struct rsnd_mod_ops *ops;
 	struct list_head list; /* connect to rsnd_dai playback/capture */
+	struct rsnd_dma dma;
 };
 
 #define rsnd_mod_to_priv(mod) ((mod)->priv)
+#define rsnd_mod_to_dma(mod) (&(mod)->dma)
+#define rsnd_dma_to_mod(_dma) container_of((_dma), struct rsnd_mod, dma)
 #define rsnd_mod_id(mod) ((mod)->id)
 #define for_each_rsnd_mod(pos, n, io)	\
 	list_for_each_entry_safe(pos, n, &(io)->head, list)