[PATCH resend] dma: pl330: Fix cyclic transfers

[PATCH resend] dma: pl330: Fix cyclic transfers

[Lars-Peter Clausen]

Allocate a descriptor for each period of a cyclic transfer, not just the first.
Also since the callback needs to be called for each finished period make sure to
initialize the callback and callback_param fields of each descriptor in a cyclic
transfer.

Cc: stable@vger.kernel.org
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
---
 drivers/dma/pl330.c | 87 ++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 66 insertions(+), 21 deletions(-)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 7c02e83..29d4476 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -2505,6 +2505,10 @@ static dma_cookie_t pl330_tx_submit(struct dma_async_tx_descriptor *tx)
 	/* Assign cookies to all nodes */
 	while (!list_empty(&last->node)) {
 		desc = list_entry(last->node.next, struct dma_pl330_desc, node);
+		if (pch->cyclic) {
+			desc->txd.callback = last->txd.callback;
+			desc->txd.callback_param = last->txd.callback_param;
+		}
 
 		dma_cookie_assign(&desc->txd);
 
@@ -2688,32 +2692,19 @@ static struct dma_async_tx_descriptor *pl330_prep_dma_cyclic(
 		size_t period_len, enum dma_transfer_direction direction,
 		unsigned long flags, void *context)
 {
-	struct dma_pl330_desc *desc;
+	struct dma_pl330_desc *desc = NULL, *first = NULL;
 	struct dma_pl330_chan *pch = to_pchan(chan);
+	struct dma_pl330_dmac *pdmac = pch->dmac;
+	unsigned int i;
 	dma_addr_t dst;
 	dma_addr_t src;
 
-	desc = pl330_get_desc(pch);
-	if (!desc) {
-		dev_err(pch->dmac->pif.dev, "%s:%d Unable to fetch desc\n",
-			__func__, __LINE__);
+	if (len % period_len != 0)
 		return NULL;
-	}
 
 	switch (direction) {
 	case DMA_MEM_TO_DEV:
-		desc->rqcfg.src_inc = 1;
-		desc->rqcfg.dst_inc = 0;
-		desc->req.rqtype = MEMTODEV;
-		src = dma_addr;
-		dst = pch->fifo_addr;
-		break;
 	case DMA_DEV_TO_MEM:
-		desc->rqcfg.src_inc = 0;
-		desc->rqcfg.dst_inc = 1;
-		desc->req.rqtype = DEVTOMEM;
-		src = pch->fifo_addr;
-		dst = dma_addr;
 		break;
 	default:
 		dev_err(pch->dmac->pif.dev, "%s:%d Invalid dma direction\n",
@@ -2721,12 +2712,66 @@ static struct dma_async_tx_descriptor *pl330_prep_dma_cyclic(
 		return NULL;
 	}
 
-	desc->rqcfg.brst_size = pch->burst_sz;
-	desc->rqcfg.brst_len = 1;
+	for (i = 0; i < len / period_len; i++) {
+		desc = pl330_get_desc(pch);
+		if (!desc) {
+			dev_err(pch->dmac->pif.dev, "%s:%d Unable to fetch desc\n",
+				__func__, __LINE__);
 
-	pch->cyclic = true;
+			if (!first)
+				return NULL;
 
-	fill_px(&desc->px, dst, src, period_len);
+			spin_lock_irqsave(&pdmac->pool_lock, flags);
+
+			while (!list_empty(&first->node)) {
+				desc = list_entry(first->node.next,
+						struct dma_pl330_desc, node);
+				list_move_tail(&desc->node, &pdmac->desc_pool);
+			}
+
+			list_move_tail(&first->node, &pdmac->desc_pool);
+
+			spin_unlock_irqrestore(&pdmac->pool_lock, flags);
+
+			return NULL;
+		}
+
+		switch (direction) {
+		case DMA_MEM_TO_DEV:
+			desc->rqcfg.src_inc = 1;
+			desc->rqcfg.dst_inc = 0;
+			desc->req.rqtype = MEMTODEV;
+			src = dma_addr;
+			dst = pch->fifo_addr;
+			break;
+		case DMA_DEV_TO_MEM:
+			desc->rqcfg.src_inc = 0;
+			desc->rqcfg.dst_inc = 1;
+			desc->req.rqtype = DEVTOMEM;
+			src = pch->fifo_addr;
+			dst = dma_addr;
+			break;
+		default:
+			break;
+		}
+
+		desc->rqcfg.brst_size = pch->burst_sz;
+		desc->rqcfg.brst_len = 1;
+		fill_px(&desc->px, dst, src, period_len);
+
+		if (!first)
+			first = desc;
+		else
+			list_add_tail(&desc->node, &first->node);
+
+		dma_addr += period_len;
+	}
+
+	if (!desc)
+		return NULL;
+
+	pch->cyclic = true;
+	desc->txd.flags = flags;
 
 	return &desc->txd;
 }
-- 
1.8.0

Re: [PATCH resend] dma: pl330: Fix cyclic transfers

[Vinod Koul]

On Tue, Jul 16, 2013 at 04:13:23PM +0200, Lars-Peter Clausen wrote:
> Allocate a descriptor for each period of a cyclic transfer, not just the first.
> Also since the callback needs to be called for each finished period make sure to
> initialize the callback and callback_param fields of each descriptor in a cyclic
> transfer.

 
>  	switch (direction) {
>  	case DMA_MEM_TO_DEV:
> -		desc->rqcfg.src_inc = 1;
> -		desc->rqcfg.dst_inc = 0;
> -		desc->req.rqtype = MEMTODEV;
> -		src = dma_addr;
> -		dst = pch->fifo_addr;
> -		break;
>  	case DMA_DEV_TO_MEM:
> -		desc->rqcfg.src_inc = 0;
> -		desc->rqcfg.dst_inc = 1;
> -		desc->req.rqtype = DEVTOMEM;
> -		src = pch->fifo_addr;
> -		dst = dma_addr;
>  		break;
>  	default:
>  		dev_err(pch->dmac->pif.dev, "%s:%d Invalid dma direction\n",
shouldnt the whole switch be removed and for error check you should use
is_slave_direction()

~Vinod