From: Christian Lamparter <chunkeey@googlemail.com>
To: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org
Cc: Christian Lamparter <chunkeey@googlemail.com>,
tj@kernel.org, mans@mansr.com, stable@vger.kernel.org
Subject: [PATCH] sata_dwc_460ex: fix burst transaction length
Date: Thu, 7 Apr 2016 00:44:55 +0200 [thread overview]
Message-ID: <1459982695-32394-1-git-send-email-chunkeey@googlemail.com> (raw)
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
next reply other threads:[~2016-04-06 22:45 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-06 22:44 Christian Lamparter [this message]
2016-04-07 17:37 ` Andy Shevchenko
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