Thread (50 messages) 50 messages, 9 authors, 2013-01-22

[RFC PATCH v3 11/16] mmc: omap_hsmmc: limit max_segs with the EDMA DMAC

From: Matt Porter <hidden>
Date: 2013-01-10 19:25:55
Also in: linux-devicetree, linux-mmc, linux-omap, linux-spi, lkml

On Mon, Oct 29, 2012 at 01:48:46PM +0530, Sekhar Nori wrote:
On 10/18/2012 6:56 PM, Matt Porter wrote:
quoted
The EDMA DMAC has a hardware limitation that prevents supporting
scatter gather lists with any number of segments. Since the EDMA
DMA Engine driver sets the maximum segments to 16, we do the
same.

TODO: this will be replaced once the DMA Engine API supports an
API to query the DMAC's segment size limit.

Signed-off-by: Matt Porter <redacted>
---
 drivers/mmc/host/omap_hsmmc.c |   10 ++++++++++
 1 file changed, 10 insertions(+)
diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index b327cd0..52bab01 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -1828,6 +1828,16 @@ static int __devinit omap_hsmmc_probe(struct platform_device *pdev)
 	 * as we want. */
 	mmc->max_segs = 1024;
 
+	/* Eventually we should get our max_segs limitation for EDMA by
+	 * querying the dmaengine API */
Nit picking: This is not as per multi-line comment style in
Documentation/CodingStyle.
Thanks :). This is dropped from v4 anyway, as I now use a call to
dma_get_channel_caps() to determine the SG limits.

-Matt
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