Re: [PATCH v2 0/2] board: sophgo: add support for Milk-V Duo 256M

[Hiago De Franco <hfranco@baylibre.com>]

Hi Andrei,

On Sun, Aug 30, 2026 at 05:29:59PM +0200, Andrei Lalaev wrote:
> Hi Hiago,
> 
> So, I've dumped the registers using downstream U-Boot and yes, Claude was right.
> By default, downstream driver configures the PHY, so the PHY registers
> have the following values:
> 
>   # PHY_TX_RX_DLY
>   milkv_duo_256m# md.l 0x04310240 1
>   04310240: 01000100                             ....
> 
>   # PHY_CONFIG
>   milkv_duo_256m# md.l 0x0431024c 1
>   0431024c: 00000001                             ....
> 
> 
> With upstream U-Boot, the same registers are always 0.
> 
> Simply setting `PHY_TX_RX_DLY` to `0x01000100` is enough to get
> the SD card working.
> 
> The attached patch contains the backported PHY configuration from the downstream
> driver & upstream kernel. Could you please take a look and check if it
> resolves the issue on your side when increasing the clock?

First, apologies for the delay on my answer, it was a busy week.

I tested your patch and it works fine ;)
Thanks for the fix. Would you mind sending this patch to u-boot ML?

If you do, add:

Fixes: eb36f28ff721 ("mmc: cv1800b: Add sdhci driver support for cv1800b SoC")

> 
> Thank you!
> 
> ---
>  drivers/mmc/cv1800b_sdhci.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/drivers/mmc/cv1800b_sdhci.c b/drivers/mmc/cv1800b_sdhci.c
> index b756649f90f3..5c129682daba 100644
> --- a/drivers/mmc/cv1800b_sdhci.c
> +++ b/drivers/mmc/cv1800b_sdhci.c
> @@ -8,11 +8,17 @@
>  #include <sdhci.h>
>  #include <linux/delay.h>
> 
> +#define CV18XX_SDHCI_MSHC_CTRL  0x200
> +#define CV18XX_SDHCI_PHY_CONFIG 0x24c
>  #define SDHCI_PHY_TX_RX_DLY  0x240
>  #define MMC_MAX_CLOCK        375000000
>  #define TUNE_MAX_PHCODE      128
> 
>  #define PHY_TX_SRC_INVERT  BIT(8)
> +#define PHY_RX_SRC_INVERT  BIT(24)
> +
> +#define CV18XX_LATANCY_1T BIT(1)
> +#define CV18XX_PHY_TX_BPS BIT(0)
> 
>  struct cv1800b_sdhci_plat {
>  	struct mmc_config cfg;
> @@ -64,10 +70,29 @@ static int cv1800b_execute_tuning(struct mmc *mmc, u8 opcode)
>  }
>  #endif
> 
> +static int cv1800b_deferred_probe(struct sdhci_host *host)
> +{
> +	u32 val;
> +
> +	val = sdhci_readl(host, CV18XX_SDHCI_MSHC_CTRL);
> +	val |= CV18XX_LATANCY_1T;
> +	sdhci_writel(host, val, CV18XX_SDHCI_MSHC_CTRL);
> +
> +	val = sdhci_readl(host, CV18XX_SDHCI_PHY_CONFIG);
> +	val |= CV18XX_PHY_TX_BPS;
> +	sdhci_writel(host, val, CV18XX_SDHCI_PHY_CONFIG);
> +
> +	val = PHY_TX_SRC_INVERT | PHY_RX_SRC_INVERT;
> +	sdhci_writel(host, val, SDHCI_PHY_TX_RX_DLY);
> +
> +	return 0;
> +}
> +
>  const struct sdhci_ops cv1800b_sdhci_sd_ops = {
>  #if CONFIG_IS_ENABLED(MMC_SUPPORTS_TUNING)
>  	.platform_execute_tuning = cv1800b_execute_tuning,
>  #endif
> +	.deferred_probe = cv1800b_deferred_probe,
>  };
> 
>  static int cv1800b_sdhci_bind(struct udevice *dev)
> --
> 2.55.0
> 
> 
> -- 
> Best regards,
> Andrei Lalaev

Regards,
-- 
Hiago