Hi Fabio and Hector,
On 12/04/2015 10:43 AM, 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 <e...@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.
>
>
I switched back to a v2014.10 release and am able to reproduce the
issue at will.
The sysctl patch had no effect, but adding an #ifndef around the
ENGcm03648 block allows things to proceed.
+#ifndef CONFIG_FSL_USDHC
/* Workaround for ESDHC errata ENGcm03648 */
if (!data && (cmd->resp_type & MMC_RSP_BUSY)) {
...
Since the need to poll the DAT0 line is only documented in the
errata for the i.MX35, I wonder if this isn't the right thing to do.
The CC bit of irqstat does indicate that the command completed
and without error (I'm seeing values of 1 in irqstat).
>From what I can tell, the linux kernel doesn't do this test and
doesn't appear to have any trouble.
What code base are you running against (u-boot-imx/master)?
What do you see if you do the same?
I had been testing against v2015.10 and the board I'm testing isn't
upstream, so I can't easily bisect.
Please advise,
Eric
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