Hello Marek-san,
> From: U-Boot On Behalf Of Marek Vasut, Sent: Monday, November 6, 2023 7:43 AM
>
> Currently the renesas_sdhi_reset_tuning() unconditionally leaves SDHI
> clock enabled after the tuning reset. This is not always necessary.
>
> After the driver performed tuning reset at the end of probe function,
> or in the unlikely case that tuning failed during regular operation,
> the SDHI clock can be disabled after the tuning reset. The following
> set_ios call would reconfigure the clock as needed.
>
> In case of regular set_ios call which requires a tuning reset, keep
> the clock enabled or disabled according to the mmc->clk_disable state.
>
> With this in place, the controllers which have not been accessed via
> block subsystem after boot are left in quiescent state. However, if an
> MMC device is used e.g. for environment storage, that controller would
> be accessed during the environment load and left active, including its
> clock which would still be generated. This is due to the design of the
> MMC subsystem, which does not deinit a controller after it was started
> once, the controller is only deinited in case of mmc rescan, or before
> OS boot.
>
> Signed-off-by: Marek Vasut <marek.vasut+rene...@mailbox.org>
> ---
> Note: To address the part where MMC device has been inited once and
> is never deinited until rescan or OS boot, it would likely be
> necessary to implement something like runtime PM, possibly
> based on the cyclic framework. Basically, keep track of when
> the MMC was accessed last, and if certain time elapsed, deinit
> the MMC. This could also be used to handle card detect polling
> at the same time.
> ---
> Cc: Jaehoon Chung <jh80.ch...@samsung.com>
> Cc: Nobuhiro Iwamatsu <iwama...@nigauri.org>
> Cc: Paul Barker <paul.barker...@bp.renesas.com>
> Cc: Peng Fan <peng....@nxp.com>
Thank you for the patch! This patch looks good to me. So,
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda...@renesas.com>
Also, our outsourcing member tested this patch on R-Car H3 Salvator-XS
And it works without any regression. So,
Tested-by: Thuan Nguyen Hong <thuan.nguyen-h...@banvien.com.vn>
Best regards,
Yoshihiro Shimoda
> ---
> drivers/mmc/renesas-sdhi.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/renesas-sdhi.c b/drivers/mmc/renesas-sdhi.c
> index 8cd501c5f7c..97aaf1e4ec3 100644
> --- a/drivers/mmc/renesas-sdhi.c
> +++ b/drivers/mmc/renesas-sdhi.c
> @@ -318,7 +318,7 @@ static unsigned int renesas_sdhi_init_tuning(struct
> tmio_sd_priv *priv)
> RENESAS_SDHI_SCC_DTCNTL_TAPNUM_MASK;
> }
>
> -static void renesas_sdhi_reset_tuning(struct tmio_sd_priv *priv)
> +static void renesas_sdhi_reset_tuning(struct tmio_sd_priv *priv, bool
> clk_disable)
> {
> u32 reg;
>
> @@ -350,6 +350,12 @@ static void renesas_sdhi_reset_tuning(struct
> tmio_sd_priv *priv)
> reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_RVSCNTL);
> reg &= ~RENESAS_SDHI_SCC_RVSCNTL_RVSEN;
> tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_RVSCNTL);
> +
> + if (clk_disable) {
> + reg = tmio_sd_readl(priv, TMIO_SD_CLKCTL);
> + reg &= ~TMIO_SD_CLKCTL_SCLKEN;
> + tmio_sd_writel(priv, reg, TMIO_SD_CLKCTL);
> + }
> }
>
> static int renesas_sdhi_hs400(struct udevice *dev)
> @@ -629,7 +635,7 @@ int renesas_sdhi_execute_tuning(struct udevice *dev, uint
> opcode)
> out:
> if (ret < 0) {
> dev_warn(dev, "Tuning procedure failed\n");
> - renesas_sdhi_reset_tuning(priv);
> + renesas_sdhi_reset_tuning(priv, true);
> }
>
> return ret;
> @@ -668,7 +674,7 @@ static int renesas_sdhi_set_ios(struct udevice *dev)
> (mmc->selected_mode != UHS_SDR104) &&
> (mmc->selected_mode != MMC_HS_200) &&
> (mmc->selected_mode != MMC_HS_400)) {
> - renesas_sdhi_reset_tuning(priv);
> + renesas_sdhi_reset_tuning(priv, mmc->clk_disable);
> }
> #endif
>
> @@ -1095,7 +1101,7 @@ static int renesas_sdhi_probe(struct udevice *dev)
> CONFIG_IS_ENABLED(MMC_HS200_SUPPORT) || \
> CONFIG_IS_ENABLED(MMC_HS400_SUPPORT)
> if (priv->caps & TMIO_SD_CAP_RCAR_UHS)
> - renesas_sdhi_reset_tuning(priv);
> + renesas_sdhi_reset_tuning(priv, true);
> #endif
> return 0;
>
> --
> 2.42.0
