[U-Boot] [PATCH] mmc: fsl_esdhc: Fix i.MX53 eSDHCv3 clock

[U-Boot] [PATCH] mmc: fsl_esdhc: Fix i.MX53 eSDHCv3 clock

[Benoît Thébaudeau]

Commit 4f425280fa71 ("mmc: fsl_esdhc: Allow all supported prescaler
values") made it possible to set SYSCTL.SDCLKFS to 0 in SDR mode on
i.MX, thus bypassing the SD clock frequency prescaler, in order to be
able to get higher SD clock frequencies in some contexts. However, that
commit missed the fact that this value is illegal on the eSDHCv3
instance of the i.MX53. This seems to be the only exception on i.MX,
this value being legal even for the eSDHCv2 instances of the i.MX53.

Fix this issue by changing the minimum prescaler value for the single
instance of the i.MX53 eSDHCv3 controller.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau.dev@gmail.com>
---
 drivers/mmc/fsl_esdhc.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
index 499d622c6d..90425e8a30 100644
--- a/drivers/mmc/fsl_esdhc.c
+++ b/drivers/mmc/fsl_esdhc.c
@@ -528,14 +528,19 @@ out:
 
 static void set_sysctl(struct fsl_esdhc_priv *priv, struct mmc *mmc, uint clock)
 {
+	struct fsl_esdhc *regs = priv->esdhc_regs;
 	int div = 1;
 #ifdef ARCH_MXC
+#ifdef CONFIG_MX53
+	/* For i.MX53 eSDHCv3, SYSCTL.SDCLKFS may not be set to 0. */
+	int pre_div = regs == (struct fsl_esdhc *)MMC_SDHC3_BASE_ADDR ? 2 : 1;
+#else
 	int pre_div = 1;
+#endif
 #else
 	int pre_div = 2;
 #endif
 	int ddr_pre_div = mmc->ddr_mode ? 2 : 1;
-	struct fsl_esdhc *regs = priv->esdhc_regs;
 	int sdhc_clk = priv->sdhc_clk;
 	uint clk;
 
-- 
2.14.1

[U-Boot] [PATCH] mmc: fsl_esdhc: Fix i.MX53 eSDHCv3 clock

[Fabio Estevam]

+ Adding Jaehoon, who is the U-Boot MMC maintainer.

On Sun, Jan 14, 2018 at 9:46 PM, Benoît Thébaudeau
<benoit.thebaudeau.dev@gmail.com> wrote:
> Commit 4f425280fa71 ("mmc: fsl_esdhc: Allow all supported prescaler
> values") made it possible to set SYSCTL.SDCLKFS to 0 in SDR mode on
> i.MX, thus bypassing the SD clock frequency prescaler, in order to be
> able to get higher SD clock frequencies in some contexts. However, that
> commit missed the fact that this value is illegal on the eSDHCv3
> instance of the i.MX53. This seems to be the only exception on i.MX,
> this value being legal even for the eSDHCv2 instances of the i.MX53.
>
> Fix this issue by changing the minimum prescaler value for the single
> instance of the i.MX53 eSDHCv3 controller.
>
> Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau.dev@gmail.com>

Thanks for your fix in U-Boot and in the kernel:

Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>


> ---
>  drivers/mmc/fsl_esdhc.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
> index 499d622c6d..90425e8a30 100644
> --- a/drivers/mmc/fsl_esdhc.c
> +++ b/drivers/mmc/fsl_esdhc.c
> @@ -528,14 +528,19 @@ out:
>
>  static void set_sysctl(struct fsl_esdhc_priv *priv, struct mmc *mmc, uint clock)
>  {
> +       struct fsl_esdhc *regs = priv->esdhc_regs;
>         int div = 1;
>  #ifdef ARCH_MXC
> +#ifdef CONFIG_MX53
> +       /* For i.MX53 eSDHCv3, SYSCTL.SDCLKFS may not be set to 0. */
> +       int pre_div = regs == (struct fsl_esdhc *)MMC_SDHC3_BASE_ADDR ? 2 : 1;
> +#else
>         int pre_div = 1;
> +#endif
>  #else
>         int pre_div = 2;
>  #endif
>         int ddr_pre_div = mmc->ddr_mode ? 2 : 1;
> -       struct fsl_esdhc *regs = priv->esdhc_regs;
>         int sdhc_clk = priv->sdhc_clk;
>         uint clk;
>
> --
> 2.14.1
>
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> https://lists.denx.de/listinfo/u-boot

[U-Boot] [PATCH] mmc: fsl_esdhc: Fix i.MX53 eSDHCv3 clock

[Stefano Babic]

Hi Benoît,

On 15/01/2018 00:46, Benoît Thébaudeau wrote:
> Commit 4f425280fa71 ("mmc: fsl_esdhc: Allow all supported prescaler
> values") made it possible to set SYSCTL.SDCLKFS to 0 in SDR mode on
> i.MX, thus bypassing the SD clock frequency prescaler, in order to be
> able to get higher SD clock frequencies in some contexts. However, that
> commit missed the fact that this value is illegal on the eSDHCv3
> instance of the i.MX53. This seems to be the only exception on i.MX,
> this value being legal even for the eSDHCv2 instances of the i.MX53.
> 
> Fix this issue by changing the minimum prescaler value for the single
> instance of the i.MX53 eSDHCv3 controller.
> 
> Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau.dev@gmail.com>
> ---
>  drivers/mmc/fsl_esdhc.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
> index 499d622c6d..90425e8a30 100644
> --- a/drivers/mmc/fsl_esdhc.c
> +++ b/drivers/mmc/fsl_esdhc.c
> @@ -528,14 +528,19 @@ out:
>  
>  static void set_sysctl(struct fsl_esdhc_priv *priv, struct mmc *mmc, uint clock)
>  {
> +	struct fsl_esdhc *regs = priv->esdhc_regs;
>  	int div = 1;
>  #ifdef ARCH_MXC
> +#ifdef CONFIG_MX53
> +	/* For i.MX53 eSDHCv3, SYSCTL.SDCLKFS may not be set to 0. */
> +	int pre_div = regs == (struct fsl_esdhc *)MMC_SDHC3_BASE_ADDR ? 2 : 1;

It is surely a question of taste - but is it not cleared to surround the
expression with parenthesis ? (regs == .... )


> +#else
>  	int pre_div = 1;
> +#endif
>  #else
>  	int pre_div = 2;
>  #endif
>  	int ddr_pre_div = mmc->ddr_mode ? 2 : 1;
> -	struct fsl_esdhc *regs = priv->esdhc_regs;
>  	int sdhc_clk = priv->sdhc_clk;
>  	uint clk;
>  
> 

Best regards,
Stefano

-- 
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DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
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Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de
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[U-Boot] [PATCH] mmc: fsl_esdhc: Fix i.MX53 eSDHCv3 clock

[Benoît Thébaudeau]

Hi Stefano,

On Mon, Jan 15, 2018 at 11:59 AM, Stefano Babic <sbabic@denx.de> wrote:
> On 15/01/2018 00:46, Benoît Thébaudeau wrote:
>> +     int pre_div = regs == (struct fsl_esdhc *)MMC_SDHC3_BASE_ADDR ? 2 : 1;
>
> It is surely a question of taste - but is it not cleared to surround the
> expression with parenthesis ? (regs == .... )

I can send a v2 for that if you want. Which of the following do you
prefer (personally, I'd say the last one)?

int pre_div = (regs == (struct fsl_esdhc *)MMC_SDHC3_BASE_ADDR ? 2 : 1);
int pre_div = (regs == (struct fsl_esdhc *)MMC_SDHC3_BASE_ADDR) ? 2 : 1;

Note that this patch can be tested with the 2nd MMC on i.MX53 Loco if
anyone has this board. Wladimir?

Best regards,
Benoît

[U-Boot] [PATCH] mmc: fsl_esdhc: Fix i.MX53 eSDHCv3 clock

[Stefano Babic]

Hi Benoît,

On 15/01/2018 22:11, Benoît Thébaudeau wrote:
> Hi Stefano,
> 
> On Mon, Jan 15, 2018 at 11:59 AM, Stefano Babic <sbabic@denx.de> wrote:
>> On 15/01/2018 00:46, Benoît Thébaudeau wrote:
>>> +     int pre_div = regs == (struct fsl_esdhc *)MMC_SDHC3_BASE_ADDR ? 2 : 1;
>>
>> It is surely a question of taste - but is it not cleared to surround the
>> expression with parenthesis ? (regs == .... )
> 
> I can send a v2 for that if you want. Which of the following do you
> prefer (personally, I'd say the last one)?
> 
> int pre_div = (regs == (struct fsl_esdhc *)MMC_SDHC3_BASE_ADDR ? 2 : 1);
> int pre_div = (regs == (struct fsl_esdhc *)MMC_SDHC3_BASE_ADDR) ? 2 : 1;
> 

I agree for last one - but as I said, it is just a question of taste.

> Note that this patch can be tested with the 2nd MMC on i.MX53 Loco if
> anyone has this board. Wladimir?

Best regards,
Stefano

-- 
=====================================================================
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de
=====================================================================