Re: [PATCH 1/3] dt-bindings: mmc: mmci: add a property to disable DMA LLI

Linus Walleij
2022-03-14T22:44:46Z

"On Fri, Mar 4, 2022 at 2:52 PM Yann Gautier <yann.gautier@foss.st.com> wrote:

> On STMicroelectronics variant of PL18x, the DMA Linked Lists are supported
> starting from revision v2 of the peripheral. But it has limitations,
> as all the buffers should be aligned on block size (except the last one).
> But this cannot be guaranteed with SDIO. We should then have a property
> to disable the support of LLI.
>
> Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>

Actually I think this is present also on the ux500 variants. See:
commit 2253ed4b36dc876d1598c4dab5587e537ec68c34
"mmc: mmci: Support any block sizes for ux500v2 and qcom variant"

Spot the variant data "dma_power_of_2".

So whatever property you add
to the variant data (not in the device tree please) should
be added to the ux500 variants as well, it will *VERY* likely
have a problem with LLI elements not being a power of 2
as it is the ancestor of later STMicro variants.

It might actually be the reason for some annoying WiFi error
messages I have seen :/

Yours,
Linus Walleij