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

Avri Altman
2022-03-16T11:09:13Z

> 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.
>
> --
> Best Regards,
> Michael Wu