On Mon, Oct 28, 2019 at 12:18:31AM +0100, Ahmad Fatoum wrote:
> Now with the SD/MMC controller supported, lets add a bbu handler, so we
> can use it to update the second stage boot loader partition.
> 
> While doing this, I noticed that making use of the bus-width = <4>
> property in the device tree now makes mmc usage fail when reading the
> environment:
> 
>   ERROR: error SDMMC_STA_DCRCFAIL (0x81042) for cmd 18
>   ERROR: stm32_sdmmc2_end_cmd: error SDMMC_STA_CTIMEOUT (0x4) for cmd 12
>   WARNING: stm32_sdmmc2_send_cmd: cmd 12 failed, retrying ...
>   ERROR: stm32_sdmmc2_end_cmd: error SDMMC_STA_CTIMEOUT (0x4) for cmd 12
>   WARNING: stm32_sdmmc2_send_cmd: cmd 12 failed, retrying ...
>   ERROR: stm32_sdmmc2_end_cmd: error SDMMC_STA_CTIMEOUT (0x4) for cmd 12
>   WARNING: stm32_sdmmc2_send_cmd: cmd 12 failed, retrying ...
>   ERROR: stm32_sdmmc2_end_cmd: error SDMMC_STA_CTIMEOUT (0x4) for cmd 12

Could you make this an extra patch?

> 
> We'll want to fix this eventually, but for now force the bus width to 1
> and print a notice to the console that we've done so. This is not
> enough, however because it then fails at loading the kernel from MMC:
> 
>   ERROR: Time out on waiting for SDMMC_STA. cmd 18
>   ERROR: stm32_sdmmc2_end_cmd: error SDMMC_STA_CTIMEOUT (0x804) for cmd 12
>   WARNING: stm32_sdmmc2_send_cmd: cmd 18 failed, retrying ...
> 
> Fixing the max frequency at 208 MHz fixes this. So do that and print a
> notice for it as well.
> 
> @@ -627,11 +627,22 @@ static int stm32_sdmmc2_probe(struct amba_device *adev,
>       if (IS_ERR(priv->reset_ctl))
>               priv->reset_ctl = NULL;
>  
> +     mci_of_parse(&priv->mci);
> +
>       mci->f_min = 400000;
> -     /* f_max is taken from kernel v5.3 variant_stm32_sdmmc */
> -     mci->f_max = 208000000;
>       mci->voltages = MMC_VDD_32_33 | MMC_VDD_33_34 | MMC_VDD_165_195;
>  
> +     if (mci->f_max != 208000000) {
> +             /* f_max is taken from kernel v5.3 variant_stm32_sdmmc */
> +             dev_notice(dev, "Fixing max-frequency to 208 MHz due to driver 
> limitation\n");
> +             mci->f_max = 208000000;
> +     }

f_max previously was hardcoded to 208MHz. It still is now, so this can't
fix anything.
Looking at the device tree we have max-frequency = <120000000>, so you
probably mean that it doesn't work with the 120MHz specified here,
right? If it doesn't work with a lower frequency it really looks fishy.

Could you have another look what is going on here?

Sascha


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