[PATCHv2 4/5] mmc: shdci-bcm2835: add verify for 32-bit back-to-back workaround

Stefan Wahren info at lategoodbye.de
Tue Dec 22 12:13:01 PST 2015

Hi Scott,

Am 22.12.2015 um 20:23 schrieb Scott Branden:
> Hi Stefan,
> On 15-12-22 07:55 AM, Stefan Wahren wrote:
>> Hi Scott,
>> Am 07.11.2014 um 19:31 schrieb Scott Branden:
>>> On 14-11-05 09:01 PM, Stephen Warren wrote:
>>>> On 11/05/2014 12:00 AM, Scott Branden wrote:
>>>>> On 14-11-04 08:59 PM, Stephen Warren wrote:
>>>>>> On 10/30/2014 12:36 AM, Scott Branden wrote:
>>>>>>> Add a verify option to driver to print out an error message if a
>>>>>>> potential back to back write could cause a clock domain issue.
>>>>>>> index f8c450a..11af27f 100644
>>>>>>> +    struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>>>>>>> +    struct bcm2835_sdhci_host *bcm2835_host = pltfm_host->priv;
>>>>>>> +
>>>>>>> +    if (bcm2835_host->previous_reg == reg) {
>>>>>>> +        if ((reg != SDHCI_HOST_CONTROL)
>>>>>>> +            && (reg != SDHCI_CLOCK_CONTROL)) {
>>>>>> The comment in patch 3 says the problem doesn't apply to the data
>>>>>> register. Why does this check for these two registers rather than
>>>>>> data?
>>>>> This Verify workaround patch still a work in progress.  I'm still
>>>>> getting more info from the silicon designers on the back-to-back
>>>>> register writes that are affect.  The spew of 0x20 or 0x28 or 0x2c
>>>>> register writes are all ok locations that don't need to be worked
>>>>> around.  This patch needs to be corrected with the proper register
>>>>> rules
>>>>> still.
>>> Thanks for testing.  Yes, I have work to do on the verify patch above
>>> still.
>> do you still have plans to submit a V3 of this patch series?
> No, I do not have plans to submit a V3 of this patch series.
> I submitted this patch as RPI has a similar controller to the SoCs I am
> familiar with as well as needing similar work arounds   You can take
> over the patchset.  Or, try and get the sdhci-iproc.c driver going on
> RPI.  The sdhci-iproc is the production driver we use on a variety of
> SoCs and support and test this driver.

after applying the patch series both drivers are very similiar so i 
prefer the latter. I will give it a try. Thanks for the hint about 


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