On 3/25/22 21:12, Linus Walleij wrote:
On Tue, Mar 15, 2022 at 9:26 AM Yann Gautier <yann.gautier@xxxxxxxxxxx> wrote:
The STM32 variant uses an internal DMA, and the DMA functions are in its
dedicated file. So I was planning to do the same as what is done in
meson-gx-mmc.c: using a bounce buffer to copy from/to in case DMA
constraints are not fulfilled. Not sure it can help for Ux500.
Ulf, before I send my new series (although it is not ready yet), would
you be OK with the bounce buffer idea?
Hi Linus,
Would it not be better if the bounce buffer is something available
for all MMCI variants and not restricted to the STM32 DMA add-on?
The issue was seen with the internal DMA of the STM32 variant of PL180.
What I'm thinking is that this is a problem with the MMCI hardware
rather than with the DMA hardware, so the problem kind of gets
fixed in the wrong place if the bounce buffer is in the DMA add-on
code.
Maybe this is how you fixed it in later patches, I'll take a look.
I've pushed a new version there to correct latest remarks from Ulf:
https://lore.kernel.org/all/20220328145114.334577-1-yann.gautier@xxxxxxxxxxx/
Yours,
Linus Walleij
Best regards,
Yann
