[U-Boot] [PATCH 2/2 v3] FSL/eSDHC: enable the clock to detect the SD card

[Huang Changming-R66093]

Hi, Andy
There is not any feedback for very long time,
Could it be applied to u-boot?

Best Regards
Jerry Huang


> -----Original Message-----
> From: u-boot-bounces at lists.denx.de [mailto:u-boot-bounces at lists.denx.de]
> On Behalf Of Huang Changming-R66093
> Sent: Monday, May 21, 2012 10:35 AM
> To: Wood Scott-B07421
> Cc: Marek Vasut; u-boot at lists.denx.de; Andy Fleming
> Subject: Re: [U-Boot] [PATCH 2/2 v3] FSL/eSDHC: enable the clock to
> detect the SD card
> 
> 
> 
> Best Regards
> Jerry Huang
> 
> 
> > -----Original Message-----
> > From: Wood Scott-B07421
> > Sent: Friday, May 18, 2012 11:55 PM
> > To: Huang Changming-R66093
> > Cc: u-boot at lists.denx.de; Marek Vasut; Andy Fleming
> > Subject: Re: [U-Boot] [PATCH 2/2 v3] FSL/eSDHC: enable the clock to
> > detect the SD card
> >
> > On 05/18/2012 04:57 AM, Chang-Ming.Huang at freescale.com wrote:
> > > From: Jerry Huang <Chang-Ming.Huang at freescale.com>
> > >
> > > For FSL low-end processors (VVN2.2), in order to detect the SD card,
> > > we should enable PEREN, HCKEN and IPGEN to enable the clock.
> > > Otherwise, after booting the u-boot, and then inserting the SD card,
> > > the SD card can't be detected.
> > > For SDHC VVN2.3 IP, these bits are reserved, and SDCLKEN is used.
> > > And when accessing to these reserved bit, no any impact happened.
> >
> > Again, have you talked to a hardware designer and confirmed that
> > there's no impact from setting these bits on chips where they're
> > reserved?  Just because you don't notice any obvious impact doesn't
> > mean it's totally safe.
> >
> Do you read the FSL SDHC driver? If not, please read it first.
> Without my this patch, FSL SDHC driver has done it as I mentioned.
> The committer provided the patch to support VVN2.3 should talk to the
> hardware designer, And he think it is safe. Otherwise he should detect
> the VVN to do the different thing.
> The below is the code driver enable these bit:
> In function set_sysctl:
> clk = SYSCTL_PEREN | SYSCTL_CKEN;
> in function esdhc_init:
> esdhc_write32(&regs->sysctl, SYSCTL_HCKEN | SYSCTL_IPGEN);
> 
> My work is just to pick up the codes from the driver and do it again in
> function fsl_esdhc_initialize:
> esdhc_setbits32(&regs->sysctl, SYSCTL_PEREN | SYSCTL_HCKEN
>                                 | SYSCTL_IPGEN | SYSCTL_CKEN);
> 
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