Re: [PATCH] mmc: renesas_sdhi: Fix card initialization failure in high speed mode

[Ulf Hansson <ulf.hansson@linaro.org>]

On Tue, 29 Jan 2019 at 06:40, <marek.vasut@gmail.com> wrote:
>
> From: Takeshi Saito <takeshi.saito.xv@renesas.com>
>
> This fixes card initialization failure in high speed mode.
>
> If U-Boot uses SDR or HS200/400 mode before starting Linux and Linux
> DT does not enable SDR/HS200/HS400 mode, card initialization fails in
> high speed mode.
>
> It is necessary to initialize SCC registers during card initialization
> phase. HW reset function is registered only for a port with either of
> SDR/HS200/HS400 properties in device tree. If SDR/HS200/HS400 properties
> are not present in device tree, SCC registers will not be reset. In SoC
> that support SCC registers, HW reset function should be registered
> regardless of the configuration of device tree.
>
> Reproduction procedure:
> - Use U-Boot that support MMC HS200/400 mode.
> - Delete HS200/HS400 properties in device tree.
>   (Delete mmc-hs200-1_8v and mmc-hs400-1_8v)
> - MMC port works high speed mode and all commands fail.
>
> Signed-off-by: Takeshi Saito <takeshi.saito.xv@renesas.com>
> Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
> Cc: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> Cc: Simon Horman <horms+renesas@verge.net.au>
> Cc: Ulf Hansson <ulf.hansson@linaro.org>
> Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Cc: linux-renesas-soc@vger.kernel.org
> To: linux-mmc@vger.kernel.org

Is this a regression? Should it be tagged for stable?

Kind regards
Uffe

> --
> NOTE: Marek: - Reworded commit message
>              - Updated patch to next/master
> ---
>  drivers/mmc/host/renesas_sdhi_core.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
> index 31a351a20dc0..7e2a75c4f36f 100644
> --- a/drivers/mmc/host/renesas_sdhi_core.c
> +++ b/drivers/mmc/host/renesas_sdhi_core.c
> @@ -723,6 +723,13 @@ int renesas_sdhi_probe(struct platform_device *pdev,
>                 host->ops.start_signal_voltage_switch =
>                         renesas_sdhi_start_signal_voltage_switch;
>                 host->sdcard_irq_setbit_mask = TMIO_STAT_ALWAYS_SET_27;
> +
> +               /* SDR and HS200/400 registers requires HW reset */
> +               if (of_data && of_data->scc_offset) {
> +                       priv->scc_ctl = host->ctl + of_data->scc_offset;
> +                       host->mmc->caps |= MMC_CAP_HW_RESET;
> +                       host->hw_reset = renesas_sdhi_hw_reset;
> +               }
>         }
>
>         /* Orginally registers were 16 bit apart, could be 32 or 64 nowadays */
> @@ -775,8 +782,6 @@ int renesas_sdhi_probe(struct platform_device *pdev,
>                 const struct renesas_sdhi_scc *taps = of_data->taps;
>                 bool hit = false;
>
> -               host->mmc->caps |= MMC_CAP_HW_RESET;
> -
>                 for (i = 0; i < of_data->taps_num; i++) {
>                         if (taps[i].clk_rate == 0 ||
>                             taps[i].clk_rate == host->mmc->f_max) {
> @@ -789,12 +794,10 @@ int renesas_sdhi_probe(struct platform_device *pdev,
>                 if (!hit)
>                         dev_warn(&host->pdev->dev, "Unknown clock rate for SDR104\n");
>
> -               priv->scc_ctl = host->ctl + of_data->scc_offset;
>                 host->init_tuning = renesas_sdhi_init_tuning;
>                 host->prepare_tuning = renesas_sdhi_prepare_tuning;
>                 host->select_tuning = renesas_sdhi_select_tuning;
>                 host->check_scc_error = renesas_sdhi_check_scc_error;
> -               host->hw_reset = renesas_sdhi_hw_reset;
>                 host->prepare_hs400_tuning =
>                         renesas_sdhi_prepare_hs400_tuning;
>                 host->hs400_downgrade = renesas_sdhi_disable_scc;
> --
> 2.19.2
>