am654_sdhci: mmc fail to send stop cmd

[Jan Kiszka]

On 21.07.20 01:23, Jaehoon Chung wrote:
> On 7/20/20 10:21 AM, Peng Fan wrote:
>> Hi Jan,
>>
>>> Subject: am654_sdhci: mmc fail to send stop cmd
>>>
>>> Hi all,
>>>
>>> on one device with one specific SD-card (possibly an aging one), I'm seeing
>>> frequent "mmc fail to send stop cmd" messages, followed by read errors
>>> when loading kernel and dtb. -ETIMEDOUT is returned by mmd_send_cmd.
>>> However, I can always resolve this by simply retrying the stop command like
>>> this:
>>>
>>> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index
>>> f36d11ddc8..9019d9f2ed 100644
>>> --- a/drivers/mmc/mmc.c
>>> +++ b/drivers/mmc/mmc.c
>>> @@ -406,7 +406,11 @@ static int mmc_read_blocks(struct mmc *mmc, void
>>> *dst, lbaint_t start,  #if !defined(CONFIG_SPL_BUILD) ||
>>> defined(CONFIG_SPL_LIBCOMMON_SUPPORT)
>>>   			pr_err("mmc fail to send stop cmd\n");  #endif
>>> -			return 0;
>>> +			pr_err("retrying...\n");
>>> +			if (mmc_send_cmd(mmc, &cmd, NULL)) {
>>> +				pr_err("failed again\n");
>>> +				return 0;
>>> +			}
>>>   		}
>>>   	}
>>>
>>>
>>> Hardware is our IOT2050, baseline is today's master (1c4b5038afcc) with
>>> board-enabling and a bunch of patches from your tree [1]. However, already
>>> 4d6da10ce611 exposes the problem.
>>>
>>> What could cause this?
>>
>> Where the timeout happen in driver?
>>
>> Did you try enlarge the timeout value?
>
> how about adding SDHCI_QUIRK_WAIT_SEND_CMD?

I tried that already, but the result was even worse, a non-working mmc.

> And as Peng's comment, It needs to find where return error in driver code.
>

As written in my other reply:
https://gitlab.denx.de/u-boot/u-boot/-/blob/f12341a9529540113f01989149bbbeb68662a829/drivers/mmc/sdhci.c#L385
Thus, it's reported by the hw.

Thanks,
Jan