[PATCH] eSDHC: Access Freescale eSDHC registers by 32-bit

[Zang Roy-R61911]

> -----Original Message-----
> From: Anton Vorontsov [mailto:cbouatmailru at gmail.com]
> Sent: Friday, September 09, 2011 22:07 PM
> To: Zang Roy-R61911
> Cc: linux-mmc at vger.kernel.org; linuxppc-dev at lists.ozlabs.org; akpm at linux-
> foundation.org; Xu Lei-B33228; Kumar Gala
> Subject: Re: [PATCH] eSDHC: Access Freescale eSDHC registers by 32-bit
> 
> On Fri, Sep 09, 2011 at 08:05:46PM +0800, Roy Zang wrote:
> > From: Xu lei <B33228 at freescale.com>
> >
> > Freescale eSDHC registers only support 32-bit accesses,
> > this patch ensures that all Freescale eSDHC register accesses
> > are 32-bit.
> >
> > Signed-off-by: Xu lei <B33228 at freescale.com>
> > Signed-off-by: Roy Zang <tie-fei.zang at freescale.com>
> > Signed-off-by: Kumar Gala <galak at kernel.crashing.org>
> > ---
> 
> The patch looks OK.
> 
> Acked-by: Anton Vorontsov <cbouatmailru at gmail.com>
Thanks.
Add Chris.

> 
> [...]
> > +static u8 esdhc_readb(struct sdhci_host *host, int reg)
> > +{
> > +	int base = reg & ~0x3;
> > +	int shift = (reg & 0x3) * 8;
> > +	u8 ret = (in_be32(host->ioaddr + base) >> shift) & 0xff;
> >  	return ret;
> >  }
> 
> Though, I wonder if we could change sdhci_be32bs_read{b,w}, instead
> of making this local to eSDHC.
> 
> The thing is: sdhci_be32bs_writeb() is using clrsetbits_be32,
> so the write variant already uses 32-bit accessors, so nothing should
> break if we switch sdhci_be32bs_readb() to in_be32().
> 
> But maybe it's safer if we do this in a separate patch, so that it
> could be easily reverted without impacting eSDHC if something actually
> breaks.
> 
> You decide. :-)
> 
> Thanks!
The suggestion makes sense. I'd like to do this in a separate patch after this patch applied.
Thanks.
Roy