[U-Boot] [PATCH] mmc:sdhci:fix: Change default interrupts enabled at SDHCI initialization

[Lukasz Majewski]

Dear All,

Any feedback about this patch?

It has been on the list for quite long time.....


> Dear All,
> 
> Any feedback about this patch?
> 
> > This patch changes sdhci_init()'s behavior to NOT enable all
> > interrupt sources by default. Moreover interrupt signaling has been
> > disabled.
> > 
> > This patch do not enable interrupts which aren't served in u-boot
> > (they are defined at sdhci.h but NOT used elsewhere):
> > - SDHCI_INT_CARD_INSERT, SDHCI_INT_CARD_REMOVE, SDHCI_BUS_POWER,
> >   SDHCI_INT_CARD_REMOVE, SDHCI_INT_CARD_INT
> > 
> > Special care shall be put on SDHCI_INT_CARD_INT, which indicates
> > interrupt generated by SD card.
> > According to "SD Host Controller Simplified Spec. ver 3.00" when
> > bit 8 (Card Interrupt Status Enable) at "Normal Interrupt Status
> > Enable Register" (offset 0x34) is set, the card interrupt detection
> > is started. Then eMMC card may cause the SD controller to set this
> > bit and then this interrupt is passed to booted OS and might cause
> > kernel crash.
> > 
> > 
> > To sum up:
> > - Only enable interrupts, which are served at u-boot
> > - This cleanup as a side effect fixes SDHCI's CARD INTERRUPT problem
> > at Linux kernel (versions 3.6+, sdhci controller)
> > - Keep masked bits at "Normal Interrupt Signal Enable
> > Register" (0x38h)
> > 
> > Signed-off-by: Lukasz Majewski <l.majewski at samsung.com>
> > Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
> > Cc: Lei Wen <leiwen at marvell.com>
> > Cc: Andy Fleming <afleming at freescale.com>
> > ---
> >  drivers/mmc/sdhci.c |    8 +++++---
> >  1 files changed, 5 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
> > index 0fd1337..76c14fb 100644
> > --- a/drivers/mmc/sdhci.c
> > +++ b/drivers/mmc/sdhci.c
> > @@ -412,9 +412,11 @@ int sdhci_init(struct mmc *mmc)
> >  			status = sdhci_readl(host,
> > SDHCI_PRESENT_STATE); }
> >  
> > -	/* Eable all state */
> > -	sdhci_writel(host, SDHCI_INT_ALL_MASK, SDHCI_INT_ENABLE);
> > -	sdhci_writel(host, SDHCI_INT_ALL_MASK,
> > SDHCI_SIGNAL_ENABLE);
> > +	/* Enable only interrupts served by the SD controller */
> > +	sdhci_writel(host, SDHCI_INT_DATA_MASK | SDHCI_INT_CMD_MASK
> > +		     , SDHCI_INT_ENABLE);
> > +	/* Mask all sdhci interrupt sources */
> > +	sdhci_writel(host, 0x0, SDHCI_SIGNAL_ENABLE);
> >  
> >  	return 0;
> >  }
> 
> 
> 



-- 
Best regards,

Lukasz Majewski

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