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authorKishore Kadiyala <kishore.kadiyala@ti.com>2010-08-10 18:01:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-08-11 08:59:03 -0700
commit27151dc9e363c0033d7375863c0d284f8c4b636a (patch)
tree401329dc2634b84f427bb4338e9f556912f4ee7a /drivers/mmc
parentfc8a0985c2846292312556cba10b8a4182f55967 (diff)
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mmc: omap: fix for bus width which improves SD card's peformance.
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 <kishore.kadiyala@ti.com> Signed-off-by: Venkatraman S <svenkatr@ti.com> Signed-off-by: Nishanth Menon <nm@ti.com> Acked-by: Madhusudhan Chikkature <madhu.cr@ti.com> Tested-by: Jarkko Nikula <jhnikula@gmail.com> Cc: Adrian Hunter <adrian.hunter@nokia.com> Cc: Matt Fleming <matt@console-pimps.org> Cc: Tony Lindgren <tony@atomide.com> Cc: <linux-mmc@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/host/omap_hsmmc.c17
1 files changed, 15 insertions, 2 deletions
diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index b032828..a0c8515 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -2096,10 +2096,23 @@ static int __init omap_hsmmc_probe(struct platform_device *pdev)
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;