Re: [PATCH v3 2/2] mmc: litex_mmc: Set mandatory idle clocks before CMD0

Re: [PATCH v3 2/2] mmc: litex_mmc: Set mandatory idle clocks before CMD0

[Ulf Hansson]

On Sun, 26 Apr 2026 at 13:20, Inochi Amaoto <inochiama@gmail.com> wrote:
>
> The litex_mmc driver assumes the card is already probed in the BIOS
> and skip the phy initialization. This will cause the command fail
> like the following when the old card is unplugged and then insert
> a new card:
>
> [   62.923593] litex-mmc f0004000.mmc: Command (cmd 8) error, status -110
> [   62.949717] litex-mmc f0004000.mmc: Command (cmd 55) error, status -110
> [   62.976606] litex-mmc f0004000.mmc: Command (cmd 55) error, status -110
> [   63.002516] litex-mmc f0004000.mmc: Command (cmd 55) error, status -110
> [   63.028442] litex-mmc f0004000.mmc: Command (cmd 55) error, status -110
>
> Add required clock settings and initialization for the CMD 0, so it can
> probe the new card.
>
> Fixes: 92e099104729 ("mmc: Add driver for LiteX's LiteSDCard interface")
> Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
> ---
>  drivers/mmc/host/litex_mmc.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/drivers/mmc/host/litex_mmc.c b/drivers/mmc/host/litex_mmc.c
> index a8d9c0ece16a..c984398d0803 100644
> --- a/drivers/mmc/host/litex_mmc.c
> +++ b/drivers/mmc/host/litex_mmc.c
> @@ -68,6 +68,9 @@
>  #define SD_SLEEP_US       5
>  #define SD_TIMEOUT_US 20000
>
> +#define SD_INIT_DELAY_US  1000
> +#define SD_INIT_CLK_HZ    400000
> +
>  #define SDIRQ_CARD_DETECT    1
>  #define SDIRQ_SD_TO_MEM_DONE 2
>  #define SDIRQ_MEM_TO_SD_DONE 4
> @@ -142,6 +145,12 @@ static int litex_mmc_send_cmd(struct litex_mmc_host *host,
>         int ret;
>         u8 evt;
>
> +       if (cmd == MMC_GO_IDLE_STATE) {

Rather than doing this explicit check for each command being sent, we
have the ->set_ios() callback where things like this belong. Please
move it there instead.

> +               litex_mmc_setclk(host, SD_INIT_CLK_HZ);
> +               litex_write8(host->sdphy + LITEX_PHY_INITIALIZE, 1);
> +               fsleep(SD_INIT_DELAY_US);
> +       }
> +
>         litex_write32(host->sdcore + LITEX_CORE_CMDARG, arg);
>         litex_write32(host->sdcore + LITEX_CORE_CMDCMD,
>                       cmd << 8 | transfer << 5 | response_len);
> --
> 2.54.0
>

Kind regards
Uffe

Re: [PATCH v3 2/2] mmc: litex_mmc: Set mandatory idle clocks before CMD0

[Inochi Amaoto]

On Mon, May 11, 2026 at 04:52:21PM +0200, Ulf Hansson wrote:
> On Sun, 26 Apr 2026 at 13:20, Inochi Amaoto <inochiama@gmail.com> wrote:
> >
> > The litex_mmc driver assumes the card is already probed in the BIOS
> > and skip the phy initialization. This will cause the command fail
> > like the following when the old card is unplugged and then insert
> > a new card:
> >
> > [   62.923593] litex-mmc f0004000.mmc: Command (cmd 8) error, status -110
> > [   62.949717] litex-mmc f0004000.mmc: Command (cmd 55) error, status -110
> > [   62.976606] litex-mmc f0004000.mmc: Command (cmd 55) error, status -110
> > [   63.002516] litex-mmc f0004000.mmc: Command (cmd 55) error, status -110
> > [   63.028442] litex-mmc f0004000.mmc: Command (cmd 55) error, status -110
> >
> > Add required clock settings and initialization for the CMD 0, so it can
> > probe the new card.
> >
> > Fixes: 92e099104729 ("mmc: Add driver for LiteX's LiteSDCard interface")
> > Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
> > ---
> >  drivers/mmc/host/litex_mmc.c | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> >
> > diff --git a/drivers/mmc/host/litex_mmc.c b/drivers/mmc/host/litex_mmc.c
> > index a8d9c0ece16a..c984398d0803 100644
> > --- a/drivers/mmc/host/litex_mmc.c
> > +++ b/drivers/mmc/host/litex_mmc.c
> > @@ -68,6 +68,9 @@
> >  #define SD_SLEEP_US       5
> >  #define SD_TIMEOUT_US 20000
> >
> > +#define SD_INIT_DELAY_US  1000
> > +#define SD_INIT_CLK_HZ    400000
> > +
> >  #define SDIRQ_CARD_DETECT    1
> >  #define SDIRQ_SD_TO_MEM_DONE 2
> >  #define SDIRQ_MEM_TO_SD_DONE 4
> > @@ -142,6 +145,12 @@ static int litex_mmc_send_cmd(struct litex_mmc_host *host,
> >         int ret;
> >         u8 evt;
> >
> > +       if (cmd == MMC_GO_IDLE_STATE) {
> 
> Rather than doing this explicit check for each command being sent, we
> have the ->set_ios() callback where things like this belong. Please
> move it there instead.
> 

OK, And I think the patch 1 can be removed if this got moved
to set_ios(). I will prepare a new version for it.

Regards,
Inochi

> > +               litex_mmc_setclk(host, SD_INIT_CLK_HZ);
> > +               litex_write8(host->sdphy + LITEX_PHY_INITIALIZE, 1);
> > +               fsleep(SD_INIT_DELAY_US);
> > +       }
> > +
> >         litex_write32(host->sdcore + LITEX_CORE_CMDARG, arg);
> >         litex_write32(host->sdcore + LITEX_CORE_CMDCMD,
> >                       cmd << 8 | transfer << 5 | response_len);
> > --
> > 2.54.0
> >
> 
> Kind regards
> Uffe