Ulf Hansson <ulf.hansson@xxxxxxxxxx> writes:
> On 20 March 2018 at 10:55, Kalle Valo <kvalo@xxxxxxxxxxxxxx> wrote:
>> Arend van Spriel <arend.vanspriel@xxxxxxxxxxxx> writes:
>>
>>>>> If I get it right, you mean something like this:
>>>>>
>>>>> mmc3: mmc@1c12000 {
>>>>> ...
>>>>> broken-sg-support;
>>>>> sd-head-align = 4;
>>>>> sd-sgentry-align = 512;
>>>>>
>>>>> brcmf: wifi@1 {
>>>>> ...
>>>>> };
>>>>> };
>>>>>
>>>>> Where dt: bindings documentation for these entries should reside?
>>>>> In generic MMC bindings? Well, this is the very special case and
>>>>> mmc-linux maintainer will unlikely to accept these changes.
>>>>> Also, extra kernel code modification might be required. It could make
>>>>> quite trivial change much more complex.
>>>>
>>>> If the MMC maintainers are not copied on this patch series, it will
>>>> likely be hard for them to identify this patch series and chime in...
>>>
>>> The main question is whether this is indeed a "very special case" as
>>> Alexey claims it to be or that it is likely to be applicable to other
>>> device and host combinations as you are suggesting.
>>>
>>> If these properties are imposed by the host or host controller it
>>> would make sense to have these in the mmc bindings.
>>
>> BTW, last year we were discussing something similar (I mean related to
>> alignment requirements) with ath10k SDIO patches and at the time the
>> patch submitter was proposing to have a bounce buffer in ath10k to
>> workaround that. I don't remember the details anymore, they are on the
>> ath10k mailing list archive if anyone is curious to know, but I would
>> not be surprised if they are similar as here. So there might be a need
>> to solve this in a generic way (but not sure of course as I haven't
>> checked the details).
>
> I re-call something about these as well, here are the patches. Perhaps
> I should pick some of them up...
>
> https://patchwork.kernel.org/patch/10123137/
> https://patchwork.kernel.org/patch/10123139/
> https://patchwork.kernel.org/patch/10123141/
> https://patchwork.kernel.org/patch/10123143/
Actually I was talking about a different patch, found it now:
ath10k_sdio: DMA bounce buffers for read write
https://patchwork.kernel.org/patch/9979543/
--
Kalle Valo
