diff mbox series

[3/3] mmc: renesas-sdhi: Do not access SCC during tuning in send_cmd callback

Message ID 20240220083755.34449-3-marek.vasut+renesas@mailbox.org
State Superseded
Delegated to: Jaehoon Chung
Headers show
Series [1/3] mmc: Convert hs400_tuning flag from u8 to bool | expand

Commit Message

Marek Vasut Feb. 20, 2024, 8:37 a.m. UTC
Do not access SCC when sending commands during tuning operation as that
will disrupt the tuning operation. The tuning operation is adjusting the
SCC settings itself in execute_tuning callback.

When renesas_sdhi_execute_tuning() is called by the MMC core code, a loop
which consists of renesas_sdhi_prepare_tuning(), mmc_send_tuning() and
renesas_sdhi_compare_scc_data() iterates over each SCC tuning tap.

The renesas_sdhi_prepare_tuning() configures the SCC tuning tap number into
hardware, mmc_send_tuning() triggers transfer of tuning block which depends
on the bus mode for which the bus is currently being tuned, this information
is supplied by the MMC core code, and finally renesas_sdhi_compare_scc_data()
tests the received tuning block for validity.

Because renesas_sdhi_prepare_tuning() configures the SCC tuning tap into
the hardware to fit the tuning operation, mmc_send_tuning() which triggers
command transfer using renesas_sdhi_send_cmd() must not manipulate with
the SCC in any way. Currently renesas_sdhi_send_cmd() does unconditionally
call renesas_sdhi_check_scc_error(), which may adjust the SCC tuning tap
position by writing RENESAS_SDHI_SCC_TAPSET, which would overwrite the
required tuning configuration set by renesas_sdhi_prepare_tuning() and
disrupt the tuning operation.

Fix this by skipping the renesas_sdhi_check_scc_error() call in case the
MMC subsystem is in tuning state. This way, the SCC settings are left
unmodified by command transfer during tuning operation.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
---
Cc: Hai Pham <hai.pham.ud@renesas.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Cc: Paul Barker <paul.barker.ct@bp.renesas.com>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Sean Anderson <seanga2@gmail.com>
Cc: Tom Rini <trini@konsulko.com>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
---
 drivers/mmc/renesas-sdhi.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

Paul Barker Feb. 20, 2024, 11 a.m. UTC | #1
On 20/02/2024 08:37, Marek Vasut wrote:
> Do not access SCC when sending commands during tuning operation as that
> will disrupt the tuning operation. The tuning operation is adjusting the
> SCC settings itself in execute_tuning callback.
> 
> When renesas_sdhi_execute_tuning() is called by the MMC core code, a loop
> which consists of renesas_sdhi_prepare_tuning(), mmc_send_tuning() and
> renesas_sdhi_compare_scc_data() iterates over each SCC tuning tap.
> 
> The renesas_sdhi_prepare_tuning() configures the SCC tuning tap number into
> hardware, mmc_send_tuning() triggers transfer of tuning block which depends
> on the bus mode for which the bus is currently being tuned, this information
> is supplied by the MMC core code, and finally renesas_sdhi_compare_scc_data()
> tests the received tuning block for validity.
> 
> Because renesas_sdhi_prepare_tuning() configures the SCC tuning tap into
> the hardware to fit the tuning operation, mmc_send_tuning() which triggers
> command transfer using renesas_sdhi_send_cmd() must not manipulate with
> the SCC in any way. Currently renesas_sdhi_send_cmd() does unconditionally
> call renesas_sdhi_check_scc_error(), which may adjust the SCC tuning tap
> position by writing RENESAS_SDHI_SCC_TAPSET, which would overwrite the
> required tuning configuration set by renesas_sdhi_prepare_tuning() and
> disrupt the tuning operation.
> 
> Fix this by skipping the renesas_sdhi_check_scc_error() call in case the
> MMC subsystem is in tuning state. This way, the SCC settings are left
> unmodified by command transfer during tuning operation.
> 
> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> ---
> Cc: Hai Pham <hai.pham.ud@renesas.com>
> Cc: Jaehoon Chung <jh80.chung@samsung.com>
> Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
> Cc: Paul Barker <paul.barker.ct@bp.renesas.com>
> Cc: Peng Fan <peng.fan@nxp.com>
> Cc: Sean Anderson <seanga2@gmail.com>
> Cc: Tom Rini <trini@konsulko.com>
> Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> ---
>  drivers/mmc/renesas-sdhi.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/renesas-sdhi.c b/drivers/mmc/renesas-sdhi.c
> index 9770b6bb5e1..316b75b35fe 100644
> --- a/drivers/mmc/renesas-sdhi.c
> +++ b/drivers/mmc/renesas-sdhi.c
> @@ -798,9 +798,12 @@ static int renesas_sdhi_send_cmd(struct udevice *dev, struct mmc_cmd *cmd,
>  #if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT) || \
>      CONFIG_IS_ENABLED(MMC_HS200_SUPPORT) || \
>      CONFIG_IS_ENABLED(MMC_HS400_SUPPORT)
> +	struct mmc_uclass_priv *upriv = dev_get_uclass_priv(dev);
>  	struct tmio_sd_priv *priv = dev_get_priv(dev);
> +	struct mmc *mmc = upriv->mmc;
>  
> -	renesas_sdhi_check_scc_error(dev);
> +	if (!mmc->tuning)
> +		renesas_sdhi_check_scc_error(dev);
>  
>  	if (cmd->cmdidx == MMC_CMD_SEND_STATUS)
>  		renesas_sdhi_adjust_hs400_mode_enable(priv);

Reviewed-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Tested-by: Paul Barker <paul.barker.ct@bp.renesas.com>
  (tested on RZ/G2L with commit ad50a8151387 from
  https://source.denx.de/u-boot/custodians/u-boot-sh)
diff mbox series

Patch

diff --git a/drivers/mmc/renesas-sdhi.c b/drivers/mmc/renesas-sdhi.c
index 9770b6bb5e1..316b75b35fe 100644
--- a/drivers/mmc/renesas-sdhi.c
+++ b/drivers/mmc/renesas-sdhi.c
@@ -798,9 +798,12 @@  static int renesas_sdhi_send_cmd(struct udevice *dev, struct mmc_cmd *cmd,
 #if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT) || \
     CONFIG_IS_ENABLED(MMC_HS200_SUPPORT) || \
     CONFIG_IS_ENABLED(MMC_HS400_SUPPORT)
+	struct mmc_uclass_priv *upriv = dev_get_uclass_priv(dev);
 	struct tmio_sd_priv *priv = dev_get_priv(dev);
+	struct mmc *mmc = upriv->mmc;
 
-	renesas_sdhi_check_scc_error(dev);
+	if (!mmc->tuning)
+		renesas_sdhi_check_scc_error(dev);
 
 	if (cmd->cmdidx == MMC_CMD_SEND_STATUS)
 		renesas_sdhi_adjust_hs400_mode_enable(priv);