[U-Boot] [PATCH 4/4] mmc: add workaround for eSDHC erratum A009620

[Jaehoon Chung <jh80.chung@samsung.com>]

On 07/27/2016 04:10 PM, Yangbo Lu wrote:
>> -----Original Message-----
>> From: york sun
>> Sent: Tuesday, July 26, 2016 1:38 AM
>> To: Yangbo Lu; u-boot at lists.denx.de
>> Subject: Re: [PATCH 4/4] mmc: add workaround for eSDHC erratum A009620
>>
>> On 05/20/2016 03:20 AM, Yangbo Lu wrote:
>>> Erratum Title:
>>> Data timeout error not getting set in case of command with busy
>>> response (R1b) as well as for busy period after last write block
>>> transfer.
>>>
>>> Description:
>>> In the event that a busy timeout occurs for a command with a busy
>>> response (e.g. R1b response) as well as busy period after the last
>>> write block, the eSDHC does not set the IRQSTAT[DTOE] bit or the
>>> IRQSTAT[TC]. Therefore, the current command transfer is never completed.
>>>
>>> Workaround:
>>> Workaround for CMD with busy:
>>> Don't set the XFRTYP[RSP]=2'b11 for commands with busy response and
>>> poll the busy status of the card from the PRSSTAT[DLSL]
>>>
>>> Workaround for busy period after last write block:
>>> 1. After the command completion interrupt (IRQSTAT[CC]), wait for
>>>    de-assertion of PRSTAT[WTA].
>>> 2. Once PRSTAT[WTA] is de-asserted, start the software timer and poll
>>>    the busy signal (DAT0) using PRSTAT[DLSL[0]].
>>> 3. Wait for DAT0 signal to go high (which indicate transfer complete)
>>>    or software timer expiry (which indicate data timeout error).
>>> 4. Issue soft reset for data (SYSCTL[RSTD]).
>>> 5. In case of data timeout error (detected in step 3) perform the
>>>    error recovery.
>>>
>>> The workaround for CMD with busy has already been applied in eSDHC
>>> driver. This patch is to add workaround for the 2nd issue, and the
>>> fixup platforms include PowerPC(P1010/P2020/P5020/P5040/T1024/T1040/
>>> T2080/T4240) and ARM(LS1021A/LS1043A/LS2080A).
>>>
>>> Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
>>> ---
>>>  arch/powerpc/include/asm/config_mpc85xx.h |  8 ++++++++
>>>  drivers/mmc/fsl_esdhc.c                   | 26
>> ++++++++++++++++++++++++++
>>>  include/configs/ls1021aqds.h              |  1 +
>>>  include/configs/ls1021atwr.h              |  1 +
>>>  include/configs/ls1043a_common.h          |  1 +
>>>  include/configs/ls2080a_simu.h            |  1 +
>>>  include/configs/ls2080aqds.h              |  1 +
>>>  include/configs/ls2080ardb.h              |  1 +
>>>  include/fsl_esdhc.h                       |  1 +
>>>  9 files changed, 41 insertions(+)
>>
>> Yangbo,
>>
>> Why do you put the macro CONFIG_SYS_FSL_ERRATUM_ESDHC_A009620 in board
>> header file if the erratum applies to the SoC?
>>
>> York
>>
> [Lu Yangbo-B47093] Thanks a lot, York. 
> Could you suggest any better place where I can put this macro?
> I didn't find such a good place :(

If use your patch by default, is there performance degression?
I don't know fsl_esdhc controller..so i just ask this. :)

> 
> Thanks.
> 
> 
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