> -----Original Message----- > From: Chris Ball [mailto:cjb@xxxxxxxxxx] > Sent: Wednesday, February 08, 2012 11:07 PM > To: Huang Changming-R66093 > Cc: linux-mmc@xxxxxxxxxxxxxxx; Huang Changming-R66093; Jain Priyanka- > B32167 > Subject: Re: [PATCH v7] ESDHC: Workaround for data crc error on p1010rdb > > Hi, > > On Wed, Feb 08 2012, r66093@xxxxxxxxxxxxx wrote: > > From: Jerry Huang <Chang-Ming.Huang@xxxxxxxxxxxxx> > > > > SD card read was failing (data crc error)on some cards at > > maximum possible frequency on P1010(CCB frequency set to 400MHz). > > Some clock deviations are also observed at this frequency. > > Hence reduced the mmc clock freq. > > > > Signed-off-by: Priyanka Jain <Priyanka.Jain@xxxxxxxxxxxxx> > > Singed-off-by: Jerry Huang <Chang-Ming.Huang@xxxxxxxxxxxxx> > > CC: Chris Ball <cjb@xxxxxxxxxx> > > Acked-by: Anton Vorontsov <cbouatmailru@xxxxxxxxx> > > Thanks, just one comment below: > > > --- > > changes for v2: > > - change the property to compatible for quirks > > changes for v3: > > - fix one compile error > > changes for v4: > > - use hooks to suspend/resume the special platform > > changes for v5: > > - add the Acked-by > > changes for v6: > > - move the workaround codes to special platform from header file > > changes for v7: > > - don't use quirks to check the platform support > > > > drivers/mmc/host/sdhci-of-esdhc.c | 19 ++++++++++++++++++- > > 1 files changed, 18 insertions(+), 1 deletions(-) > > drivers/mmc/host/sdhci-of-esdhc.c | 24 ++++++++++++++++++++++-- > > 1 files changed, 22 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/mmc/host/sdhci-of-esdhc.c > b/drivers/mmc/host/sdhci-of-esdhc.c > > index 2ef52f4..acac541 100644 > > --- a/drivers/mmc/host/sdhci-of-esdhc.c > > +++ b/drivers/mmc/host/sdhci-of-esdhc.c > > @@ -1,7 +1,7 @@ > > /* > > * Freescale eSDHC controller driver. > > * > > - * Copyright (c) 2007, 2010 Freescale Semiconductor, Inc. > > + * Copyright (c) 2007, 2010, 2012 Freescale Semiconductor, Inc. > > * Copyright (c) 2009 MontaVista Software, Inc. > > * > > * Authors: Xiaobo Xie <X.Xie@xxxxxxxxxxxxx> > > @@ -14,6 +14,7 @@ > > */ > > > > #include <linux/io.h> > > +#include <linux/of.h> > > #include <linux/delay.h> > > #include <linux/module.h> > > #include <linux/mmc/host.h> > > @@ -114,6 +115,25 @@ static unsigned int esdhc_of_get_min_clock(struct > sdhci_host *host) > > return pltfm_host->clock / 256 / 16; > > } > > > > +static void esdhc_of_set_clock(struct sdhci_host *host, unsigned int > clock) > > +{ > > + /* Workaround to reduce the clock frequency for p1010 esdhc */ > > + if (of_find_compatible_node(NULL, NULL, "fsl,p1010-esdhc")) { > > + if (clock == 0) { > > + host->clock = clock; > > + return; > > + } > > Is this if (clock == 0) necessary? You'll be calling esdhc_set_clock() > immediately afterwards, and it performs the same test. Yes, I perform this test two times. The first time, I test the original value (as the parameter from set_clock) The second time, I test it again, that is because the clock value has been changed or reduced, I think it is necessary to test it again. Thanks Jerry Huang -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
