[U-Boot] [PATCH] powerpc/esdhc: force the bus width to 4bit

From: Marek Vasut <marex@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] powerpc/esdhc: force the bus width to 4bit
Date: Thu, 1 Nov 2012 03:29:54 +0100	[thread overview]
Message-ID: <201211010329.54758.marex@denx.de> (raw)
In-Reply-To: <110EED8CC96DFC488B7E717A2027A27C2058C8@039-SN1MPN1-003.039d.mgd.msft.net>

Dear Huang Changming-R66093,

Fixing the ML address ... and reposting the rest.

> Andy,
> Do you agree my suggest to revert these codes to fix this issue?

Please ... do us all a favor, read [1] and stop being so inconsiderate of 
others! Given that I can no longer make any sense of this thread because of your 
top-posting making it complete utmost mess, my opinion is NAK on reverting them.

[1] http://www.ietf.org/rfc/rfc1855.txt

> Best Regards
> Jerry Huang
> 
> > -----Original Message-----
> > From: u-boot-bounces at linux.freescale.net [mailto:u-boot-
> > bounces at linux.freescale.net] On Behalf Of Huang Changming-R66093
> > Sent: Wednesday, October 31, 2012 10:08 AM
> > To: Andy Fleming; Marek Vasut
> > Cc: u-boot at linux.freescale.net
> > Subject: Re: [u-boot] [PATCH] powerpc/esdhc: force the bus width to 4bit
> > 
> > Below is the old codes (width = 2):
> > 
> > } else {
> > 
> >                 for (width = EXT_CSD_BUS_WIDTH_8; width >= 0; width--) {
> > 
> > the current codes for MMC card has been changed to:
> > 
> > } else {
> > 
> > 	width = ((mmc->host_caps & MMC_MODE_MASK_WIDTH_BITS) >>
> > 	
> >                          MMC_MODE_WIDTH_BITS_SHIFT);
> > 	
> > 	for (; width >= 0; width--) {
> > 	....
> > 
> > FSL ESDHC driver set the host_caps = MMC_MODE_4BIT | MMC_MODE_8BIT;
> > So for FSL ESDHC, the width = 3, after implement mmc_switch successfully,
> > will set the bus to 4 * width.
> > Therefore, I will get the 12bit (4 x 3) bus width.
> > 
> > I don't know why do this modification?
> > If to fix the stack bug, then I need to revert these codes.
> > Andy, do you agree it?
> > 
> > Best Regards
> > Jerry Huang
> > 
> > > -----Original Message-----
> > > From: Andy Fleming [mailto:afleming at gmail.com]
> > > Sent: Tuesday, October 30, 2012 10:34 PM
> > > To: Marek Vasut
> > > Cc: Huang Changming-R66093; u-boot at linux.freescale.net
> > > Subject: Re: [PATCH] powerpc/esdhc: force the bus width to 4bit
> > > 
> > > On Oct 30, 2012, at 5:50, Marek Vasut <marex@denx.de> wrote:
> > > > Dear Chang-Ming.Huang at freescale.com,
> > > > 
> > > >> From: Jerry Huang <Chang-Ming.Huang@freescale.com>
> > > >> 
> > > >> For the current u-boot codes, only 4bit/1bit SD/SDHC bus width is
> > > 
> > > support.
> > > 
> > > >> So for MMC card, we also support 4bit bus width, otherwiase, we will
> > > > 
> > > >> get the 12bit bus width, which is not correct:
> > > > [...]
> > > > 
> > > >> --- a/drivers/mmc/fsl_esdhc.c
> > > >> +++ b/drivers/mmc/fsl_esdhc.c
> > > >> @@ -577,7 +577,7 @@ int fsl_esdhc_initialize(bd_t *bis, struct
> > > >> fsl_esdhc_cfg *cfg) return -1;
> > > >> 
> > > >>    }
> > > >> 
> > > >> -    mmc->host_caps = MMC_MODE_4BIT | MMC_MODE_8BIT;
> > > >> +    mmc->host_caps = MMC_MODE_4BIT;
> > > > 
> > > > This fix is not correct, fix the MMC subsystem please.
> > > 
> > > Agreed. Bit width just needs smarter printing. Unless this patch is
> > 
> > doing
> > 
> > > more than ensuring the printout is correct
> > > 
> > > Andy
> > 
> > _______________________________________________
> > u-boot mailing list
> > u-boot at linux.freescale.net
> > http://linux.freescale.net/mailman/listinfo/u-boot