* [PATCH v2 2/2] dmaengine: s3c24xx-dma: Add cyclic transfer support
2014-05-19 17:05 [PATCH v2 1/2] dmaengine: s3c24xx-dma: Process whole SG chain Vasily Khoruzhick
@ 2014-05-19 17:05 ` Vasily Khoruzhick
2014-05-20 8:31 ` Andy Shevchenko
0 siblings, 1 reply; 4+ messages in thread
From: Vasily Khoruzhick @ 2014-05-19 17:05 UTC (permalink / raw)
To: linux-arm-kernel
Many audio interface drivers require support of cyclic transfers to work
correctly, for example Samsung ASoC DMA driver. This patch adds support
for cyclic transfers to the s3c24xx-dma driver
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
---
v2: make a code a bit shorter by using is_slave_direction()
drivers/dma/s3c24xx-dma.c | 112 +++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 111 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/s3c24xx-dma.c b/drivers/dma/s3c24xx-dma.c
index 2167608..141e220 100644
--- a/drivers/dma/s3c24xx-dma.c
+++ b/drivers/dma/s3c24xx-dma.c
@@ -164,6 +164,7 @@ struct s3c24xx_sg {
* @disrcc: value for source control register
* @didstc: value for destination control register
* @dcon: base value for dcon register
+ * @cyclic: indicate cyclic transfer
*/
struct s3c24xx_txd {
struct virt_dma_desc vd;
@@ -173,6 +174,7 @@ struct s3c24xx_txd {
u32 disrcc;
u32 didstc;
u32 dcon;
+ bool cyclic;
};
struct s3c24xx_dma_chan;
@@ -669,8 +671,10 @@ static irqreturn_t s3c24xx_dma_irq(int irq, void *data)
/* when more sg's are in this txd, start the next one */
if (!list_is_last(txd->at, &txd->dsg_list)) {
txd->at = txd->at->next;
+ if (txd->cyclic)
+ vchan_cyclic_callback(&txd->vd);
s3c24xx_dma_start_next_sg(s3cchan, txd);
- } else {
+ } else if (!txd->cyclic) {
s3cchan->at = NULL;
vchan_cookie_complete(&txd->vd);
@@ -682,6 +686,12 @@ static irqreturn_t s3c24xx_dma_irq(int irq, void *data)
s3c24xx_dma_start_next_txd(s3cchan);
else
s3c24xx_dma_phy_free(s3cchan);
+ } else {
+ vchan_cyclic_callback(&txd->vd);
+
+ /* Cyclic: reset at beginning */
+ txd->at = txd->dsg_list.next;
+ s3c24xx_dma_start_next_sg(s3cchan, txd);
}
}
spin_unlock(&s3cchan->vc.lock);
@@ -877,6 +887,104 @@ static struct dma_async_tx_descriptor *s3c24xx_dma_prep_memcpy(
return vchan_tx_prep(&s3cchan->vc, &txd->vd, flags);
}
+static struct dma_async_tx_descriptor *s3c24xx_dma_prep_dma_cyclic(
+ struct dma_chan *chan, dma_addr_t addr, size_t size, size_t period,
+ enum dma_transfer_direction direction, unsigned long flags,
+ void *context)
+{
+ struct s3c24xx_dma_chan *s3cchan = to_s3c24xx_dma_chan(chan);
+ struct s3c24xx_dma_engine *s3cdma = s3cchan->host;
+ const struct s3c24xx_dma_platdata *pdata = s3cdma->pdata;
+ struct s3c24xx_dma_channel *cdata = &pdata->channels[s3cchan->id];
+ struct s3c24xx_txd *txd;
+ struct s3c24xx_sg *dsg;
+ unsigned sg_len;
+ dma_addr_t slave_addr;
+ u32 hwcfg = 0;
+ int i;
+
+ dev_dbg(&s3cdma->pdev->dev,
+ "prepare cyclic transaction of %d bytes with period %d from %s\n",
+ size, period, s3cchan->name);
+
+ if (!is_slave_direction(direction)) {
+ dev_err(&s3cdma->pdev->dev,
+ "direction %d unsupported\n", direction);
+ return NULL;
+ }
+
+ txd = s3c24xx_dma_get_txd();
+ if (!txd)
+ return NULL;
+
+ txd->cyclic = 1;
+
+ if (cdata->handshake)
+ txd->dcon |= S3C24XX_DCON_HANDSHAKE;
+
+ switch (cdata->bus) {
+ case S3C24XX_DMA_APB:
+ txd->dcon |= S3C24XX_DCON_SYNC_PCLK;
+ hwcfg |= S3C24XX_DISRCC_LOC_APB;
+ break;
+ case S3C24XX_DMA_AHB:
+ txd->dcon |= S3C24XX_DCON_SYNC_HCLK;
+ hwcfg |= S3C24XX_DISRCC_LOC_AHB;
+ break;
+ }
+
+ /*
+ * Always assume our peripheral desintation is a fixed
+ * address in memory.
+ */
+ hwcfg |= S3C24XX_DISRCC_INC_FIXED;
+
+ /*
+ * Individual dma operations are requested by the slave,
+ * so serve only single atomic operations (S3C24XX_DCON_SERV_SINGLE).
+ */
+ txd->dcon |= S3C24XX_DCON_SERV_SINGLE;
+
+ if (direction == DMA_MEM_TO_DEV) {
+ txd->disrcc = S3C24XX_DISRCC_LOC_AHB |
+ S3C24XX_DISRCC_INC_INCREMENT;
+ txd->didstc = hwcfg;
+ slave_addr = s3cchan->cfg.dst_addr;
+ txd->width = s3cchan->cfg.dst_addr_width;
+ } else {
+ txd->disrcc = hwcfg;
+ txd->didstc = S3C24XX_DIDSTC_LOC_AHB |
+ S3C24XX_DIDSTC_INC_INCREMENT;
+ slave_addr = s3cchan->cfg.src_addr;
+ txd->width = s3cchan->cfg.src_addr_width;
+ }
+
+ sg_len = size / period;
+
+ for (i = 0; i < sg_len; i++) {
+ dsg = kzalloc(sizeof(*dsg), GFP_NOWAIT);
+ if (!dsg) {
+ s3c24xx_dma_free_txd(txd);
+ return NULL;
+ }
+ list_add_tail(&dsg->node, &txd->dsg_list);
+
+ dsg->len = period;
+ /* Check last period length */
+ if (i == (sg_len - 1))
+ dsg->len = size - (period * i);
+ if (direction == DMA_MEM_TO_DEV) {
+ dsg->src_addr = addr + (period * i);
+ dsg->dst_addr = slave_addr;
+ } else { /* DMA_DEV_TO_MEM */
+ dsg->src_addr = slave_addr;
+ dsg->dst_addr = addr + (period * i);
+ }
+ }
+
+ return vchan_tx_prep(&s3cchan->vc, &txd->vd, flags);
+}
+
static struct dma_async_tx_descriptor *s3c24xx_dma_prep_slave_sg(
struct dma_chan *chan, struct scatterlist *sgl,
unsigned int sg_len, enum dma_transfer_direction direction,
@@ -1197,6 +1305,7 @@ static int s3c24xx_dma_probe(struct platform_device *pdev)
/* Initialize slave engine for SoC internal dedicated peripherals */
dma_cap_set(DMA_SLAVE, s3cdma->slave.cap_mask);
+ dma_cap_set(DMA_CYCLIC, s3cdma->slave.cap_mask);
dma_cap_set(DMA_PRIVATE, s3cdma->slave.cap_mask);
s3cdma->slave.dev = &pdev->dev;
s3cdma->slave.device_alloc_chan_resources =
@@ -1206,6 +1315,7 @@ static int s3c24xx_dma_probe(struct platform_device *pdev)
s3cdma->slave.device_tx_status = s3c24xx_dma_tx_status;
s3cdma->slave.device_issue_pending = s3c24xx_dma_issue_pending;
s3cdma->slave.device_prep_slave_sg = s3c24xx_dma_prep_slave_sg;
+ s3cdma->slave.device_prep_dma_cyclic = s3c24xx_dma_prep_dma_cyclic;
s3cdma->slave.device_control = s3c24xx_dma_control;
/* Register as many memcpy channels as there are physical channels */
--
1.9.3
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