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[06/22] mmc: omap_hsmmc: limit scatterlist size for sDMA autoloading

Message ID 1304596282-4095-7-git-send-email-adrian.hunter@nokia.com (mailing list archive)
State New, archived
Headers show

Commit Message

Adrian Hunter May 5, 2011, 11:51 a.m. UTC 
The sDMA descriptor autoloading feature uses a fixed size
buffer to store descriptors for scatterlist segments.
That limits the scatterlist size to the maximum number
of descriptors that fit in the buffer.  The driver must
set this limit for upper layers to obey.

Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
---
 drivers/mmc/host/omap_hsmmc.c |   15 ++++++++++++---
 1 files changed, 12 insertions(+), 3 deletions(-)
diff mbox

Patch

diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index 114cd68..bab25ff 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -2239,9 +2239,18 @@  static int __init omap_hsmmc_probe(struct platform_device *pdev)
 			host->dma_caps |= DMA_TYPE_SDMA_DLOAD;
 	}
 
-	/* Since we do only SG emulation, we can have as many segs
-	 * as we want. */
-	mmc->max_segs = 1024;
+	if (host->dma_caps & DMA_TYPE_SDMA_DLOAD) {
+		unsigned int max = DMA_CTRL_BUF_SIZE /
+				   sizeof(struct omap_dma_sglist_node);
+
+		mmc->max_segs = 1 << (fls(max) - 1);
+	} else {
+		/*
+		 * Since we do only SG emulation, we can have as many segs as we
+		 * want.
+		 */
+		mmc->max_segs = 1024;
+	}
 
 	mmc->max_blk_size = 512;       /* Block Length at max can be 1024 */
 	mmc->max_blk_count = 0xFFFF;    /* No. of Blocks is 16 bits */