Re: [PATCH] mmc: block: enable cache-flushing when mmc cache is on

Adrian Hunter
2022-03-16T11:28:26Z

On 16.3.2022 13.09, Avri Altman wrote:
>> Hi Avril & Adrian,
>> Thanks for your efforts. Could we have an agreement now --
>>
>> 1. enabling-cache and cmd23/reliable-write should be independent;
>>
>> Here's what I found in the spec JESD84-B51:
>> > 6.6.31 Cache
>> > Caching of data shall apply only for the single block
>> > read/write(CMD17/24), pre-defined multiple block
>> > read/write(CMD23+CMD18/25) and open ended multiple block
>> > read/write(CMD18/25+CMD12) commands and excludes any other access
>> > e.g., to the register space(e.g., CMD6).
>> Which means with CMD18/25+CMD12 (without using CMD23), the cache can
>> also be enabled. Maybe this could be an evidence of the independence
>> between enabling-cache and cmd23/reliable-write?
> Acked-by: Avri Altman <avri.altman@wdc.com>
>
> Thanks,
> Avri
>
>>
>> 2. We don't consider supporting SD in this change.
>>
>> > On 14/03/2022 19:10, Avri Altman wrote:
>> >> Here is what our SD system guys wrote:
>> >> " In SD we don’t support reliable write and this eMMC driver may not
>> >> be utilizing the cache feature we added in SD5.0.
>> >> The method of cache flush is different between SD and eMMC."
>> >>
>> >> So adding SD seems to be out of scope of this change.
>>
>> Is there anything else I can do about this patch? Thanks again.

So we are not going to let the block layer know about SD cache?
Or is it a separate change?