RE: [PATCH v2] mmc: sdhci-of-esdhc: fixup PRESENT_STATE read

[Michael Walle]

Am 2016-11-14 04:00, schrieb Y.B. Lu:
> > -----Original Message-----
> > From: Michael Walle [mailto:michael@xxxxxxxx]
> > Sent: Saturday, November 12, 2016 12:04 AM
> > To: linux-kernel@xxxxxxxxxxxxxxx
> > Cc: linux-mmc@xxxxxxxxxxxxxxx; Ulf Hansson; Adrian Hunter; yangbo lu;
> > Michael Walle
> > Subject: [PATCH v2] mmc: sdhci-of-esdhc: fixup PRESENT_STATE read
> >
> > 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>
> > Fixes: 87a18a6a5652 ("mmc: mmc: Use ->card_busy() to detect busy cards 
> > in
> > __mmc_switch()")
> > ---
> > v2:
> >  - use lower bits of the original value (that was actually a typo)
> >  - add fixes tag
> >  - fix typo
> >
> >  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..f9c84bb 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 register. Move the
> > corresponding
> > +	 * bits around.
> > +	 */
> > +	if (spec_reg == SDHCI_PRESENT_STATE) {
> > +		ret = value & ~0xf8000000;
>
> [Lu Yangbo-B47093] I think the bits which should be cleaned before
> following '|=' are 0x01f00000 not 0xf8000000, right?
> :)

Its neither 0x01f00000 nor 0xf8000000 :( I'll put the bits definition 
into the comment the next time, so everyone can review them. bit[31:24] 
are the line DAT[7:0] line signal level. bit[23] is command signal 
level. All other bits are the same as in the standard SDHC PRESENT_STATE 
register.

I want to keep all but the upper 9 bits from the original value, 
therefore, this should be the correct mask:
	ret = value & ~0xff800000;

-michael

> > +		ret |= (value >> 4) & SDHCI_DATA_LVL_MASK;
> > +		ret |= (value << 1) & 0x01000000;
> > +		return ret;
> > +	}
> > +
> >  	ret = value;
> >  	return ret;
> >  }
> > --
> > 2.1.4