[Linux-stm32] [PATCH 02/13] mmc: mmci: Clear busy_status when starting command

[Ulf Hansson]

On Wed, 5 Apr 2023 at 08:50, Linus Walleij <linus.walleij at linaro.org> wrote:
>
> If we are starting a command which can generate a busy
> response, then clear the variable host->busy_status
> if the variant is using a ->busy_complete callback.
>
> We are lucky that the member is zero by default and
> hopefully always gets cleared in the ->busy_complete
> callback even on errors, but it's just fragile so
> make sure it is always initialized to zero.
>
> Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
> ---
>  drivers/mmc/host/mmci.c | 23 ++++++++++++++---------
>  1 file changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> index bc150c0d5eed..3e08b2e95550 100644
> --- a/drivers/mmc/host/mmci.c
> +++ b/drivers/mmc/host/mmci.c
> @@ -1238,17 +1238,22 @@ mmci_start_command(struct mmci_host *host, struct mmc_command *cmd, u32 c)
>                         c |= host->variant->cmdreg_srsp;
>         }
>
> -       if (host->variant->busy_timeout && cmd->flags & MMC_RSP_BUSY) {
> -               if (!cmd->busy_timeout)
> -                       cmd->busy_timeout = 10 * MSEC_PER_SEC;
> +       if (cmd->flags & MMC_RSP_BUSY) {
> +               if (host->ops->busy_complete)
> +                       host->busy_status = 0;

I think it would be even more safe to clear host->busy_status, even if
"cmd->flags & MMC_RSP_BUSY" isn't set.  Don't you think?

>
> -               if (cmd->busy_timeout > host->mmc->max_busy_timeout)
> -                       clks = (unsigned long long)host->mmc->max_busy_timeout * host->cclk;
> -               else
> -                       clks = (unsigned long long)cmd->busy_timeout * host->cclk;
> +               if (host->variant->busy_timeout) {
> +                       if (!cmd->busy_timeout)
> +                               cmd->busy_timeout = 10 * MSEC_PER_SEC;
> +
> +                       if (cmd->busy_timeout > host->mmc->max_busy_timeout)
> +                               clks = (unsigned long long)host->mmc->max_busy_timeout * host->cclk;
> +                       else
> +                               clks = (unsigned long long)cmd->busy_timeout * host->cclk;
>
> -               do_div(clks, MSEC_PER_SEC);
> -               writel_relaxed(clks, host->base + MMCIDATATIMER);
> +                       do_div(clks, MSEC_PER_SEC);
> +                       writel_relaxed(clks, host->base + MMCIDATATIMER);
> +               }
>         }
>
>         if (host->ops->pre_sig_volt_switch && cmd->opcode == SD_SWITCH_VOLTAGE)

Kind regards
Uffe