Re: [PATCH v1] mtd: rawnand: meson: fix bitmask for length in command word

[Martin Blumenstingl]

Hello Arseniy,

thank you for submitting this fix!

On Wed, Mar 22, 2023 at 7:45 PM Arseniy Krasnov
<avkrasnov@xxxxxxxxxxxxxx> wrote:
>
> Valid mask is 0x3FFF, without this patch the following problems were
> found:
>
> 1) [    0.938914] Could not find a valid ONFI parameter page, trying
>                   bit-wise majority to recover it
>    [    0.947384] ONFI parameter recovery failed, aborting
>
> 2) Read with disabled ECC mode was broken.
>
> Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
> Signed-off-by: Arseniy Krasnov <AVKrasnov@xxxxxxxxxxxxxx>
This matches what I can see in the old vendor driver, so:
Acked-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>

[...]
> -               cmd = (len & GENMASK(5, 0)) | scrambler | DMA_DIR(dir);
> +               cmd = (len & GENMASK(13, 0)) | scrambler | DMA_DIR(dir);
My understanding of the vendor driver is that this "len" is only used
for "raw" access (my own words: any access that doesn't use the HW ECC
engine).
As a future improvement (no need to update re-send this patch) it
would be great to have a #define with a meaningful name for
"GENMASK(13, 0)" (maybe something like NFC_CMD_RAW_LENGTH) as it's
used in multiple places now


Best regards,
Martin