Chris, Thanks. I will think about how to handle it and rework it. > -----Original Message----- > From: Chris Ball [mailto:cjb@xxxxxxxxxx] > Sent: Sunday, February 05, 2012 6:22 AM > To: Huang Changming-R66093 > Cc: linux-mmc@xxxxxxxxxxxxxxx; Huang Changming-R66093; Jain Priyanka- > B32167 > Subject: Re: [PATCH 4/4 v5] ESDHC: Workaround for data crc error on > p1010rdb > > Hi Jerry, > > On Mon, Jan 16 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> > > --- > > 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 > > > > drivers/mmc/host/sdhci-esdhc.h | 9 ++++++++- > > drivers/mmc/host/sdhci-pltfm.c | 3 +++ > > include/linux/mmc/sdhci.h | 2 ++ > > 3 files changed, 13 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/mmc/host/sdhci-esdhc.h > > b/drivers/mmc/host/sdhci-esdhc.h index b97b2f5..8e00174 100644 > > --- a/drivers/mmc/host/sdhci-esdhc.h > > +++ b/drivers/mmc/host/sdhci-esdhc.h > > @@ -1,7 +1,7 @@ > > /* > > * Freescale eSDHC controller driver generics for OF and pltfm. > > * > > - * Copyright (c) 2007 Freescale Semiconductor, Inc. > > + * Copyright (c) 2007,2011 Freescale Semiconductor, Inc. > > * Copyright (c) 2009 MontaVista Software, Inc. > > * Copyright (c) 2010 Pengutronix e.K. > > * Author: Wolfram Sang <w.sang@xxxxxxxxxxxxxx> > > @@ -56,6 +56,13 @@ static inline void esdhc_set_clock(struct sdhci_host > *host, unsigned int clock) > > if (clock == 0) > > goto out; > > > > + if (host->quirks2 & SDHCI_QUIRK2_RELAX_FREQ) { > > + if (clock > 20000000) > > + clock -= 5000000; > > + if (clock > 40000000) > > + clock -= 5000000; > > + } > > + > > while (host->max_clk / pre_div / 16 > clock && pre_div < 256) > > pre_div *= 2; > > > > diff --git a/drivers/mmc/host/sdhci-pltfm.c > > b/drivers/mmc/host/sdhci-pltfm.c index 04fa130..c932316 100644 > > --- a/drivers/mmc/host/sdhci-pltfm.c > > +++ b/drivers/mmc/host/sdhci-pltfm.c > > @@ -81,6 +81,9 @@ void sdhci_get_of_property(struct platform_device > *pdev) > > "fsl,mpc8536-esdhc")) > > host->quirks |= SDHCI_QUIRK_BROKEN_TIMEOUT_VAL; > > > > + if (of_device_is_compatible(np, "fsl,p1010-esdhc")) > > + host->quirks2 |= SDHCI_QUIRK2_RELAX_FREQ; > > + > > clk = of_get_property(np, "clock-frequency", &size); > > if (clk && size == sizeof(*clk) && *clk) > > pltfm_host->clock = be32_to_cpup(clk); diff --git > > a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h index > > e4b6935..f7c1e13 100644 > > --- a/include/linux/mmc/sdhci.h > > +++ b/include/linux/mmc/sdhci.h > > @@ -91,6 +91,8 @@ struct sdhci_host { > > unsigned int quirks2; /* More deviations from spec. */ > > > > #define SDHCI_QUIRK2_OWN_CARD_DETECTION (1<<0) > > +/* Controller operates the cards at reduced frequency */ > > +#define SDHCI_QUIRK2_RELAX_FREQ (1<<1) > > > > int irq; /* Device IRQ */ > > void __iomem *ioaddr; /* Mapped address */ > > I don't think this should be implemented as a global SDHCI quirk, because > I don't think it's ever going to be used on non-ESDHC hardware. > Since you're already handling the clock change in an esdhc-only function, > can you just use your "fsl,p1010-esdhc" test to set some driver-local > flag to use later, instead of involving sdhci.h? > > Thanks. (No need to resend the other patches, I'll take this one > separately when it's been reworked.) > > - Chris. > -- > Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/> > One Laptop Per Child -- 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
