[U-Boot] [PATCH] ARM: imx: fsl_esdhc: fix usage of low 4 bits of sysctl register

[Hector Palacios <hector.palacios@digi.com>]

Hi Eric,

On 12/04/2015 06:43 PM, Eric Nelson wrote:
> On 12/04/2015 10:38 AM, Eric Nelson wrote:
>> On 12/04/2015 10:32 AM, Eric Nelson wrote:
>>> The low four bits of the SYSCTL register are reserved on the USDHC
>>> controller on i.MX6 and i.MX7 processors, but are used for clocking
>>> operations on earlier models.
>>>
>>> Guard against their usage by hiding the bit mask macros on those
>>> processors.
>>>
>>> These bits are used to prevent glitches when changing clocks on
>>> i.MX35 et al. Use the RSTA bit instead for i.MX6 and i.MX7.
>>>
>>> From the i.MX6DQ RM:
>>> 	To prevent possible glitch on the card clock, clear the
>>> 	FRC_SDCLK_ON bit when changing clock divisor value(SDCLKFS
>>> 	or DVS in System Control Register) or setting RSTA bit.
>>>
>>> Signed-off-by: Eric Nelson <eric@nelint.com>
>>
>> I forgot to add an in-reply-to header.
>>
>> http://lists.denx.de/pipermail/u-boot/2015-December/thread.html#236651
>>
>>
> 
> Fabio, I haven't been able to reproduce the "mmc erase/ENGcm03648"
> issue (with or without a code change) for a couple of hours now.
> 
> Can you give this a spin?
> 
> It seems unlikely to address the issue unless what we're seeing is a
> side effect of a glitch while switching clocks.

As Fabio, I can reproduce this 100% of the times.
The patch does not fix it, though.

--
Hector Palacios