[U-Boot] mmc erase fails from U-Boot command line

[Eric Nelson <eric@nelint.com>]

Hi Michael,

On 12/02/2015 01:00 PM, Michael Trimarchi wrote:
> Hi
> 
> On Wed, Dec 2, 2015 at 8:54 PM, Fabio Estevam <festevam@gmail.com> wrote:
>> Hi Michael,
>>
>> On Wed, Dec 2, 2015 at 5:37 PM, Michael Trimarchi
>> <michael@amarulasolutions.com> wrote:
>>
>>> Can you print the sysctl & 0xF? I want to check if this workaround is
>>> really applied
>>
>> In my testing I see the error with or without the ENGcm03648 workaround.
>>
> 
> Well the workaround works if the sysctl is 0xf on the last bits,
> because it needs the
> clocks enable according to the original description.
> 
> http://git.freescale.com/git/cgit.cgi/imx/uboot-imx.git/commit/drivers/mmc/imx_esdhc.c?h=imx_v2009.08_12.01.01&id=e436525a70fe47623d346bc7d9f08f12ff8ad787
> 
> So if you hit this timeout without having this set, I don't think it can work
>

I think you're onto something.

According to the i.MX35 reference manual, which I think was the origin
of this patch, the low four bits of the SYSCTL register of the SDHC5
	3	- SDCLKEN
	2	- PEREN
	1	- HCKEN
	0	- IPGEN

See page 603 of
http://cache.freescale.com/files/dsp/doc/ref_manual/IMX35RM.pdf

But in the i.MX6 reference manual, the low four bits are reserved and
say "Always write as 1".

See pages 5679-5680 of
http://cache.freescale.com/files/32bit/doc/ref_manual/IMX6DQRM.pdf

It appears that when this patch was ported from the Freescale version,
the test for "is_usdhc" was lost.

http://git.denx.de/?p=u-boot.git;a=commitdiff;h=7a5b80297bc6cef0c10e5f57ac0450678dc7bc5e