linux-kernel - [PATCH 01/13] dmaengine: edma: Remove alignment constraint for memcpy

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Date:	Wed, 14 Oct 2015 16:12:12 +0300
From:	Peter Ujfalusi <peter.ujfalusi@...com>
To:	<vinod.koul@...el.com>, <nsekhar@...com>, <linux@....linux.org.uk>
CC:	<olof@...om.net>, <arnd@...db.de>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <linux-omap@...r.kernel.org>,
	<dmaengine@...r.kernel.org>, <devicetree@...r.kernel.org>,
	<tony@...mide.com>, <r.schwebel@...gutronix.de>
Subject: [PATCH 01/13] dmaengine: edma: Remove alignment constraint for memcpy

Despite the claim by the original commit adding the memcpy
support, eDMA does not have constraint on the alignment of src, dst
or length in increment mode.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
---
 drivers/dma/edma.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 7eefbf1e1c94..b36dfa5458cb 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -1324,6 +1324,7 @@ static struct dma_async_tx_descriptor *edma_prep_dma_memcpy(
 	struct edma_desc *edesc;
 	struct device *dev = chan->device->dev;
 	struct edma_chan *echan = to_edma_chan(chan);
+	unsigned int width;
 
 	if (unlikely(!echan || !len))
 		return NULL;
@@ -1336,8 +1337,12 @@ static struct dma_async_tx_descriptor *edma_prep_dma_memcpy(
 
 	edesc->pset_nr = 1;
 
+	width = 1 << __ffs((src | dest | len));
+	if (width > DMA_SLAVE_BUSWIDTH_64_BYTES)
+		width = DMA_SLAVE_BUSWIDTH_64_BYTES;
+
 	ret = edma_config_pset(chan, &edesc->pset[0], src, dest, 1,
-			       DMA_SLAVE_BUSWIDTH_4_BYTES, len, DMA_MEM_TO_MEM);
+			       width, len, DMA_MEM_TO_MEM);
 	if (ret < 0)
 		return NULL;
 
@@ -1903,12 +1908,6 @@ static void edma_dma_init(struct edma_cc *ecc, struct dma_device *dma,
 
 	dma->dev = dev;
 
-	/*
-	 * code using dma memcpy must make sure alignment of
-	 * length is at dma->copy_align boundary.
-	 */
-	dma->copy_align = DMAENGINE_ALIGN_4_BYTES;
-
 	INIT_LIST_HEAD(&dma->channels);
 }
 
-- 
2.6.1

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