Re: [PATCH] MMC: OMAP: fix the maximum timeout setting

[Ulf Hansson]

On Sat, 2 Feb 2019 at 23:15, Aaro Koskinen <aaro.koskinen@xxxxxx> wrote:
>
> When running OMAP1 kernel on QEMU, MMC access is annoyingly noisy:
>
>         MMC: CTO of 0xff and 0xfe cannot be used!
>         MMC: CTO of 0xff and 0xfe cannot be used!
>         MMC: CTO of 0xff and 0xfe cannot be used!
>         [ad inf.]
>
> Emulator warnings appear to be valid. The TI document SPRU680 [1]
> ("OMAP5910 Dual-Core Processor MultiMedia Card/Secure Data Memory Card
> (MMC/SD) Reference Guide") page 36 states that the maximum timeout
> is 253 cycles and "0xff and 0xfe cannot be used".
>
> Fix by using 0xfd as the maximum timeout.
>
> Tested using QEMU 2.5 (Siemens SX1 machine, OMAP310), and also checked
> on real hardware using Palm TE (OMAP310), Nokia 770 (OMAP1710)
> and Nokia N810 (OMAP2420) that MMC works as before.
>
> [1] http://www.ti.com/lit/ug/spru680/spru680.pdf
>
> Fixes: 730c9b7e6630f ("[MMC] Add OMAP MMC host driver")
> Signed-off-by: Aaro Koskinen <aaro.koskinen@xxxxxx>

Applied for next, thanks!

Kind regards
Uffe


> ---
>  drivers/mmc/host/omap.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/omap.c b/drivers/mmc/host/omap.c
> index c60a7625b1fa..b2873a2432b6 100644
> --- a/drivers/mmc/host/omap.c
> +++ b/drivers/mmc/host/omap.c
> @@ -920,7 +920,7 @@ static inline void set_cmd_timeout(struct mmc_omap_host *host, struct mmc_reques
>         reg &= ~(1 << 5);
>         OMAP_MMC_WRITE(host, SDIO, reg);
>         /* Set maximum timeout */
> -       OMAP_MMC_WRITE(host, CTO, 0xff);
> +       OMAP_MMC_WRITE(host, CTO, 0xfd);
>  }
>
>  static inline void set_data_timeout(struct mmc_omap_host *host, struct mmc_request *req)
> --
> 2.17.0
>