Re: [PATCH] mmc: sdhci-of-esdhc: fixup PRESENT_STATE read

[Michael Walle]

Am 2016-11-11 14:15, schrieb Adrian Hunter:
> On 10/11/16 18:47, Michael Walle wrote:
> > Since commit 87a18a6a5652 ("mmc: mmc: Use ->card_busy() to detect busy
> > cards in __mmc_switch()") the ESDHC driver is broken:
> >   mmc0: Card stuck in programming state! __mmc_switch
> >   mmc0: error -110 whilst initialising MMC card
> >
> > Since this commit __mmc_switch() uses ->card_busy(), which is
> > sdhci_card_busy() for the esdhc driver. sdhci_card_busy() uses the
> > PRESENT_STATE register, specifically the DAT0 signal level bit. But 
> > the
> > ESDHC uses a non-conformant PRESENT_STATE register, thus a read fixup 
> > is
> > required to make the driver work again.
> >
> > Signed-off-by: Michael Walle <michael@xxxxxxxx>
>
> Could add a Fixes tag here.

ah, right, will do :)

> > ---
> >  drivers/mmc/host/sdhci-of-esdhc.c | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
> >
> > diff --git a/drivers/mmc/host/sdhci-of-esdhc.c 
> > b/drivers/mmc/host/sdhci-of-esdhc.c
> > index fb71c86..243fee9 100644
> > --- a/drivers/mmc/host/sdhci-of-esdhc.c
> > +++ b/drivers/mmc/host/sdhci-of-esdhc.c
> > @@ -66,6 +66,18 @@ static u32 esdhc_readl_fixup(struct sdhci_host 
> > *host,
> >  			return ret;
> >  		}
> >  	}
> > +	/*
> > +	 * The DAT[3:0] line signal levels and the CMD line signal level is
> > +	 * not compatible with standard SDHC reegister. Move the 
> > corresponding
>
> reegister -> register
ok

> > +	 * bits around.
> > +	 */
> > +	if (spec_reg == SDHCI_PRESENT_STATE) {
> > +		ret = value & 0xf8000000;
> > +		ret |= (value >> 4) & SDHCI_DATA_LVL_MASK;
> > +		ret |= (value << 1) & 0x01000000;
> > +		return ret;
>
> SDHCI also uses other bits in SDHCI_PRESENT_STATE like 
> SDHCI_CMD_INHIBIT and
> SDHCI_DATA_INHIBIT etc, but this looks like all those bits will be 
> zero.  Is
> that right?

ugh, thanks for spotting that. actually all lower bits should be taken 
from the original value. Therefore the first statement should be
 ret = value & ~0xf8000000;

Will post a v2 soon.

-michael