[PATCH-V2] OMAP: Fix for bus width which improves SD card's peformance.
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From: kishore kadiyala on 31 Mar 2010 02:10 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(a)ti.com> Signed-off-by: Venkatraman S <svenkatr(a)ti.com> Acked-by: Madhusudhan Chikkature <madhu.cr(a)ti.com> --- In V2 : Appended Signed-off by Venkat and Ack by Madhu Here are my experiment numbers, on a Class 6 SDHC card: Read peformance is increased by 220% Write Performance is increased by 52% drivers/mmc/host/omap_hsmmc.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c index 83f0aff..8c97c22 100644 --- a/drivers/mmc/host/omap_hsmmc.c +++ b/drivers/mmc/host/omap_hsmmc.c @@ -2092,7 +2092,7 @@ static int __init omap_hsmmc_probe(struct MMC_CAP_WAIT_WHILE_BUSY; if (mmc_slot(host).wires >= 8) - mmc->caps |= MMC_CAP_8_BIT_DATA; + mmc->caps |= (MMC_CAP_8_BIT_DATA | MMC_CAP_4_BIT_DATA); else if (mmc_slot(host).wires >= 4) mmc->caps |= MMC_CAP_4_BIT_DATA; -- 1.6.3.3 On Thu, Feb 11, 2010 at 11:04 PM, Madhusudhan <madhu.cr(a)ti.com> wrote: > > >> -----Original Message----- >> From: kishore kadiyala [mailto:kishore.kadiyala(a)ti.com] >> Sent: Thursday, February 11, 2010 8:20 AM >> To: linux-omap(a)vger.kernel.org; linux-kernel(a)vger.kernel.org >> Cc: jarkko.lavinen(a)nokia.com; madhu.cr(a)ti.com >> Subject: [PATCH] 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 peformance. >> This patch fixes the issue and improves the performance of >> SD cards. >> >> Signed-off-by: Kishore Kadiyala <kishore.kadiyala(a)ti.com> > > ACK > > Acked-by: Madhusudhan Chikkature <madhu.cr(a)ti.com> > >> --- >> �Here are my experiment numbers, on a Class 6 SDHC card: >> �Read peformance is increased by 220% >> �Write Performance is increased by 52% >> >> �drivers/mmc/host/omap_hsmmc.c | � �2 +- >> �1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c >> index 83f0aff..8c97c22 100644 >> --- a/drivers/mmc/host/omap_hsmmc.c >> +++ b/drivers/mmc/host/omap_hsmmc.c >> @@ -2092,7 +2092,7 @@ static int __init omap_hsmmc_probe(struct >> platform_device >> *pdev) >> � � � � � � � � � �MMC_CAP_WAIT_WHILE_BUSY; >> >> � � � if (mmc_slot(host).wires >= 8) >> - � � � � � � mmc->caps |= MMC_CAP_8_BIT_DATA; >> + � � � � � � mmc->caps |= (MMC_CAP_8_BIT_DATA | MMC_CAP_4_BIT_DATA); >> � � � else if (mmc_slot(host).wires >= 4) >> � � � � � � � mmc->caps |= MMC_CAP_4_BIT_DATA; >> >> -- >> 1.6.3.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo(a)vger.kernel.org > More majordomo info at �http://vger.kernel.org/majordomo-info.html > Please read the FAQ at �http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |