[PATCH] OMAP: HSMMC: avoid erratum workaround when transceiver is attached

Grazvydas Ignotas notasas at gmail.com
Fri Mar 16 08:49:54 EDT 2012


If transceiver is attached to a MMC host of ES2.1 OMAP, it seems
2.1.1.128 erratum doesn't apply and there is no data corruption,
probably because of different signal timing. The workaround for this
erratum disables multiblock reads, which causes dramatic loss of
performance (over 75% slower), so avoid it when transceiver is present.

Cc: Paul Walmsley <paul at pwsan.com>
Signed-off-by: Grazvydas Ignotas <notasas at gmail.com>
---
 arch/arm/mach-omap2/hsmmc.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/hsmmc.c b/arch/arm/mach-omap2/hsmmc.c
index 100db62..b0268ea 100644
--- a/arch/arm/mach-omap2/hsmmc.c
+++ b/arch/arm/mach-omap2/hsmmc.c
@@ -506,6 +506,13 @@ static void __init omap_hsmmc_init_one(struct omap2_hsmmc_info *hsmmcinfo,
 	if (oh->dev_attr != NULL) {
 		mmc_dev_attr = oh->dev_attr;
 		mmc_data->controller_flags = mmc_dev_attr->flags;
+		/*
+		 * erratum 2.1.1.128 doesn't apply if board has
+		 * a transceiver is attached
+		 */
+		if (hsmmcinfo->transceiver)
+			mmc_data->controller_flags &=
+				~OMAP_HSMMC_BROKEN_MULTIBLOCK_READ;
 	}
 
 	pdev = platform_device_alloc(name, ctrl_nr - 1);
-- 
1.7.0.4




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