[PATCH] mmc: sdhci-of-dwcmshc: Change DLL_STRBIN_TAPNUM_DEFAULT to 0x4

[Shawn Lin]

在 2025/10/22 星期三 4:24, Dragan Simic 写道:
> Hello Hugh and Shawn.
> 
> On Tuesday, October 21, 2025 22:04 CEST, Hugh Cole-Baker <sigmaris at gmail.com> wrote:
>> On 20/10/2025 02:49, Shawn Lin wrote:
>>> strbin signal delay under 0x8 configuration is not stable after massive
>>> test. The recommandation of it should be 0x4.
>>>
>>> Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com>
>>> ---
>>>
>>>   drivers/mmc/host/sdhci-of-dwcmshc.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c
>>> index eebd453..5b61401 100644
>>> --- a/drivers/mmc/host/sdhci-of-dwcmshc.c
>>> +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c
>>> @@ -94,7 +94,7 @@
>>>   #define DLL_TXCLK_TAPNUM_DEFAULT	0x10
>>>   #define DLL_TXCLK_TAPNUM_90_DEGREES	0xA
>>>   #define DLL_TXCLK_TAPNUM_FROM_SW	BIT(24)
>>> -#define DLL_STRBIN_TAPNUM_DEFAULT	0x8
>>> +#define DLL_STRBIN_TAPNUM_DEFAULT	0x4
>>>   #define DLL_STRBIN_TAPNUM_FROM_SW	BIT(24)
>>>   #define DLL_STRBIN_DELAY_NUM_SEL	BIT(26)
>>>   #define DLL_STRBIN_DELAY_NUM_OFFSET	16
>>
>> This patch gets the Foresee A3A444 eMMC on my NanoPC-T6 board to work reliably
>> in HS400 Enhanced Strobe mode; before this patch it would suffer from I/O
>> errors in HS400 mode as discussed in the other thread [1].
>>
>> Tested-by: Hugh Cole-Baker <sigmaris at gmail.com>

Thanks for testing and comfirming it works as expected.
I think this patch also need to be backported. So Ulf,
could you please help add fixes tag if the patch looks good
to you, to avoid a v2 just for adding this. :)

Fixes: 08f3dff799d4 ("mmc: sdhci-of-dwcmshc: add rockchip platform 
support")

> 
> Those are great results, thanks for the testing, Hugh!  Of course,
> huge thanks to Shawn for fixing the root cause of the issue, which
> avoided the need for having a questionable HS200 quirk described
> in the above-mentioned linux-rockchip thread. [1]
> 
>> [1]: https://lore.kernel.org/linux-rockchip/52537005-b8a3-c202-770c-599efc6a4d17@manjaro.org/T/
> 
>