Re: [PATCH v4] mmc: litex_mmc: Set mandatory idle clocks before CMD0

[Gabriel L. Somlo]

with this patch on top of today's latest (4d3a2a466b8d), I get
(on 64-bit rocketchip with Litex):

[    6.475114] mmc0: invalid bus width
[    6.477870] mmc0: error -22 whilst initialising SD card

Thanks,
--Gabriel

On Sun, May 17, 2026 at 09:53:23AM +0800, Inochi Amaoto 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@xxxxxxxxx>
> ---
> Changed from v3:
> - https://lore.kernel.org/linux-mmc/20260426112016.1370929-1-inochiama@xxxxxxxxx/
> 1. Remove patch 1: mmc: litex_mmc: Move litex_mmc_setclk() to bottom for reuse
> 2. Use set_ios() callback to apply the clock change.
> 
> Changed from v2:
> - https://lore.kernel.org/linux-mmc/20260424013615.470325-1-inochiama@xxxxxxxxx/
> 1. Remove the added function forward reference and add a new patch
>    for moving litex_mmc_setclk() function
> 
> Change from v1:
> - https://lore.kernel.org/linux-mmc/20260421025052.755471-1-inochiama@xxxxxxxxx/
> 1. use fsleep to replace udelay
> 
> Inochi Amaoto (2):
>   mmc: litex_mmc: Move litex_mmc_setclk() to bottom for reuse
>   mmc: litex_mmc: Set mandatory idle clocks before CMD0
> 
>  drivers/mmc/host/litex_mmc.c | 37 ++++++++++++++++++++++--------------
>  1 file changed, 23 insertions(+), 14 deletions(-)
> ---
>  drivers/mmc/host/litex_mmc.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/mmc/host/litex_mmc.c b/drivers/mmc/host/litex_mmc.c
> index d2f19c2dc673..65d5c728f536 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
> @@ -449,6 +452,9 @@ static void litex_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>  {
>  	struct litex_mmc_host *host = mmc_priv(mmc);
> 
> +	if (ios->chip_select == MMC_CS_HIGH)
> +		ios->clock = SD_INIT_CLK_HZ;
> +
>  	/*
>  	 * NOTE: Ignore any ios->bus_width updates; they occur right after
>  	 * the mmc core sends its own acmd6 bus-width change notification,
> @@ -459,6 +465,11 @@ static void litex_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>  	/* Update sd_clk */
>  	if (ios->clock != host->sd_clk)
>  		litex_mmc_setclk(host, ios->clock);
> +
> +	if (ios->chip_select == MMC_CS_HIGH) {
> +		litex_write8(host->sdphy + LITEX_PHY_INITIALIZE, 1);
> +		fsleep(SD_INIT_DELAY_US);
> +	}
>  }
> 
>  static const struct mmc_host_ops litex_mmc_ops = {
> --
> 2.54.0
>