Re: [PATCH 3/4] hw/sd/sdcard: Erase blocks to zero

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 19/9/25 14:34, Christian Speich wrote:
> Currently, erased blocks are filled with 0xFF. However SCR Bit 55
> (DATA_STAT_AFTER_ERASE) indicates that an erase produces zeros. One of
> them is wrong.

You are right, we don't set DATA_STAT_AFTER_ERASE correctly.

> As erasing to zero is more performant and allows block devices to
> use optimizations, we the erase to produce 0x00.
> 
> Signed-off-by: Christian Speich <c.speich@avm.de>
> ---
>   hw/sd/sd.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/sd/sd.c b/hw/sd/sd.c
> index 23764ed99f36cf39ee7abe02f08e51897c05e718..94ef3cc62582717ee044c4b114b7f22bd1b4a256 100644
> --- a/hw/sd/sd.c
> +++ b/hw/sd/sd.c
> @@ -1115,7 +1115,6 @@ static void sd_erase(SDState *sd)
>       sd->erase_end = INVALID_ADDRESS;
>       sd->csd[14] |= 0x40;
>   
> -    memset(sd->data, 0xff, erase_len);
>       for (erase_addr = erase_start; erase_addr <= erase_end;
>            erase_addr += erase_len) {
>           if (sdsc) {
> @@ -1127,7 +1126,8 @@ static void sd_erase(SDState *sd)
>                   continue;
>               }
>           }
> -        sd_blk_write(sd, erase_addr, erase_len);
> +        blk_pwrite_zeroes(sd->blk, erase_addr + sd_part_offset(sd),
> +                          erase_len, 0);
>       }
>   }

I'm OK with this change, but I'd rather having a device boolean property
so we can keep the old behavior for backward compatibility. Maybe
'erase-block-as-zero'? Do you mind updating this patch?

Regards,

Phil.