The patch titled
mmc: omap: fix for bus width which improves SD card's peformance.
has been added to the -mm tree. Its filename is
mmc-omap-fix-for-bus-width-which-improves-sd-cards-peformance.patch
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------------------------------------------------------
Subject: mmc: omap: fix for bus width which improves SD card's peformance.
From: Kishore Kadiyala <[email protected]>
This patch improves low speeds for SD cards.
OMAP-MMC controller's can support maximum bus width of '8'. when bus
width is mentioned as "8" in controller data,the SD stack will check
whether bus width is "4" and if not it will set bus width to "1" and there
by degrading performance. This patch fixes the issue and improves the
performance of SD cards.
Signed-off-by: Kishore Kadiyala <[email protected]>
Signed-off-by: Venkatraman S <[email protected]>
Signed-off-by: Nishanth Menon <[email protected]>
Acked-by: Madhusudhan Chikkature <[email protected]>
Tested-by: Jarkko Nikula <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Matt Fleming <[email protected]>
Cc: Tony Lindgren <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
drivers/mmc/host/omap_hsmmc.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff -puN
drivers/mmc/host/omap_hsmmc.c~mmc-omap-fix-for-bus-width-which-improves-sd-cards-peformance
drivers/mmc/host/omap_hsmmc.c
---
a/drivers/mmc/host/omap_hsmmc.c~mmc-omap-fix-for-bus-width-which-improves-sd-cards-peformance
+++ a/drivers/mmc/host/omap_hsmmc.c
@@ -2096,10 +2096,23 @@ static int __init omap_hsmmc_probe(struc
mmc->caps |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED |
MMC_CAP_WAIT_WHILE_BUSY;
- if (mmc_slot(host).wires >= 8)
+ switch (mmc_slot(host).wires) {
+ case 8:
mmc->caps |= MMC_CAP_8_BIT_DATA;
- else if (mmc_slot(host).wires >= 4)
+ /* Fall through */
+ case 4:
mmc->caps |= MMC_CAP_4_BIT_DATA;
+ break;
+ case 1:
+ /* Nothing to crib here */
+ case 0:
+ /* Assuming nothing was given by board, Core use's 1-Bit */
+ break;
+ default:
+ /* Completely unexpected.. Core goes with 1-Bit Width */
+ dev_crit(mmc_dev(host->mmc), "Invalid width %d\n used!"
+ "using 1 instead\n", mmc_slot(host).wires);
+ }
if (mmc_slot(host).nonremovable)
mmc->caps |= MMC_CAP_NONREMOVABLE;
_
Patches currently in -mm which might be from [email protected] are
mmc-omap-fix-for-bus-width-which-improves-sd-cards-peformance.patch
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