[U-Boot] [PATCH] mx6: fsl_esdhc: Fix waiting for DMA operation completion

[Eric Nelson <eric.nelson@boundarydevices.com>]

Thanks Dirk,

On 04/02/2013 11:10 AM, Dirk Behme wrote:
> Am 02.04.2013 17:49, schrieb Eric Nelson:
>> Thanks Andrew,
>>
>> On 04/02/2013 03:04 AM, Andrew Gabbasov wrote:
>>> On iMX6 sometimes the Transfer Complete interrupt occurs earlier
>>> than the DMA part completes its operation. If immediately after that
>>> the read data is used for some data verification, those obtained data
>>> may be incomplete, which causes intermittent verification failures.
>>>
>>
>> Can you describe how to repeat this?
>>
>>> For example, when the default environment command tries to load and run
>>> boot script from FAT partition on SD/MMC card, it sometimes fails,
>>> reporting invalid partition table, or unknown partition type, or
>>> something else of that kind. Such errors disappear if the build
>>> configuration has CONFIG_SYS_FSL_ESDHC_USE_PIO, or if some delay
>>> is added after transfer completion.
>>>
>> We do this on every boot on SABRE Lite and Nitrogen6x boards,
>> and haven't seen an issue.
>>
>> What board are you testing on?
>>
>> Do you have cache enabled?
>>
>> Is this with an SD card or eMMC?
>
> Andrew will have the details, but to my understanding this implements in
> U-Boot what the Freescale kernel has in
>
> http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/drivers/mmc/host/sdhci-esdhc-imx.c?h=imx_3.0.35_12.09.01#n234
>

Andrew, did you trap one of these?