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Subject[PATCH] sata_dwc_460ex: fix burst transaction length
Date
According to DesignWare DW_ahb_dmac Databook page 159,
both SRC_MSIZE and DEST_MSIZE values "are not related to
AHB bus mater HBURST bus".

The hardware uses these values as a unit of TR_WIDTHs.
As both TR_WIDTHs are hardcoded to 4 Bytes, the MSIZEs
should be 16, so the burst transaction length will be:
64 Bytes.

Cc: stable@vger.kernel.org
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
---
drivers/ata/sata_dwc_460ex.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/ata/sata_dwc_460ex.c b/drivers/ata/sata_dwc_460ex.c
index 2fc1516..52f0614 100644
--- a/drivers/ata/sata_dwc_460ex.c
+++ b/drivers/ata/sata_dwc_460ex.c
@@ -58,7 +58,8 @@
#define NO_IRQ 0
#endif

-#define AHB_DMA_BRST_DFLT 64 /* 16 data items burst length*/
+#define AHB_DMA_BRST_DFLT 64
+#define BRST_TRANS_LEN_DFLT 16

enum {
SATA_DWC_MAX_PORTS = 1,
@@ -381,8 +382,8 @@ static struct dma_async_tx_descriptor *dma_dwc_xfer_setup(struct ata_queued_cmd
}

sconf.direction = qc->dma_dir;
- sconf.src_maxburst = AHB_DMA_BRST_DFLT;
- sconf.dst_maxburst = AHB_DMA_BRST_DFLT;
+ sconf.src_maxburst = BRST_TRANS_LEN_DFLT;
+ sconf.dst_maxburst = BRST_TRANS_LEN_DFLT;
sconf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
sconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;

--
2.8.0.rc3
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