[PATCH] mmc: sdhci: Rework SDHCI_QUIRK_BROKEN_R1B

[Henrik Grimler]

Hi Sean,

Tested on odroid-u2 (exynos4412-odroid) on top of 2024.01-rc1, still
works fine, so feel free to add:

Tested-by: Henrik Grimler <henrik at grimler.se>

Best regards,
Henrik Grimler

On Fri, Oct 27, 2023 at 04:57:03PM -0400, Sean Anderson wrote:
> As noted in commit 3a6383207be ("mmc: sdhci: add the quirk for broken
> r1b response"), some MMC controllers don't always set the transfer
> complete bit with R1b responses.
> 
> According to the SD Host Controller Simplified Specification v4.20,
> 
> > In the case of a command pairing with response-with-busy[, Transfer
> > Complete] is set when busy is de-asserted. Refer to DAT Line Active
> > and Command Inhibit (DAT) in the Present State register.
> 
> By polling the DAT Line Active bit in the present state register, we can
> detect when we are no longer busy, without waiting for a long timeout.
> This results in much faster reads/writes on buggy controllers.
> 
> Signed-off-by: Sean Anderson <sean.anderson at seco.com>
> ---
> I've CC'd a few people who've added this quirk to controllers recently.
> Please let me know if your hardware still works. It's possible that my
> hardware is buggy in a different way.
> 
>  drivers/mmc/sdhci.c | 19 ++++++++++++-------
>  include/sdhci.h     |  1 +
>  2 files changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
> index fc9c6c37996..0178ed8a11e 100644
> --- a/drivers/mmc/sdhci.c
> +++ b/drivers/mmc/sdhci.c
> @@ -306,14 +306,19 @@ static int sdhci_send_command(struct mmc *mmc, struct mmc_cmd *cmd,
>  		if (stat & SDHCI_INT_ERROR)
>  			break;
>  
> -		if (get_timer(start) >= SDHCI_READ_STATUS_TIMEOUT) {
> -			if (host->quirks & SDHCI_QUIRK_BROKEN_R1B) {
> +		if (host->quirks & SDHCI_QUIRK_BROKEN_R1B &&
> +		    cmd->resp_type & MMC_RSP_BUSY && !data) {
> +			unsigned int state =
> +				sdhci_readl(host, SDHCI_PRESENT_STATE);
> +
> +			if (!(state & SDHCI_DAT_ACTIVE))
>  				return 0;
> -			} else {
> -				printf("%s: Timeout for status update!\n",
> -				       __func__);
> -				return -ETIMEDOUT;
> -			}
> +		}
> +
> +		if (get_timer(start) >= SDHCI_READ_STATUS_TIMEOUT) {
> +			printf("%s: Timeout for status update: %08x %08x\n",
> +			       __func__, stat, mask);
> +			return -ETIMEDOUT;
>  		}
>  	} while ((stat & mask) != mask);
>  
> diff --git a/include/sdhci.h b/include/sdhci.h
> index 70fefca2a97..a1b74e3bd79 100644
> --- a/include/sdhci.h
> +++ b/include/sdhci.h
> @@ -57,6 +57,7 @@
>  #define SDHCI_PRESENT_STATE	0x24
>  #define  SDHCI_CMD_INHIBIT	BIT(0)
>  #define  SDHCI_DATA_INHIBIT	BIT(1)
> +#define  SDHCI_DAT_ACTIVE	BIT(2)
>  #define  SDHCI_DOING_WRITE	BIT(8)
>  #define  SDHCI_DOING_READ	BIT(9)
>  #define  SDHCI_SPACE_AVAILABLE	BIT(10)
> -- 
> 2.35.1.1320.gc452695387.dirty
>