[PATCH] cpufreq: imx6q: Disable only available frequencies

[PATCH] cpufreq: imx6q: Disable only available frequencies

[Christoph Niedermaier]

In the example in Documentation/power/opp.rst, an availability check
is present before disabling a specific frequency. If a frequency isn't
available, the warning of a failed disabling of a non-existent
frequency is misleading. Therefore, check the availability of the
frequency in a separate inline function before disabling it.

Signed-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
---
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <festevam@denx.de>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: linux-pm@vger.kernel.org (open list:CPU FREQUENCY SCALING FRAMEWORK)
Cc: linux-kernel@vger.kernel.org (open list)
To: linux-arm-kernel@lists.infradead.org
---
 drivers/cpufreq/imx6q-cpufreq.c | 27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
index 48e1772e98fd..4e2d2bc47aba 100644
--- a/drivers/cpufreq/imx6q-cpufreq.c
+++ b/drivers/cpufreq/imx6q-cpufreq.c
@@ -209,6 +209,21 @@ static struct cpufreq_driver imx6q_cpufreq_driver = {
 	.suspend = cpufreq_generic_suspend,
 };
 
+static inline int disable_freq_if_available(struct device *dev,
+					    unsigned long freq)
+{
+	struct dev_pm_opp *opp;
+	int ret = 0;
+
+	opp = dev_pm_opp_find_freq_exact(dev, freq, true);
+	if (!IS_ERR(opp)) {
+		dev_pm_opp_put(opp);
+		ret = dev_pm_opp_disable(dev, freq);
+	}
+
+	return ret;
+}
+
 #define OCOTP_CFG3			0x440
 #define OCOTP_CFG3_SPEED_SHIFT		16
 #define OCOTP_CFG3_SPEED_1P2GHZ		0x3
@@ -254,16 +269,16 @@ static int imx6q_opp_check_speed_grading(struct device *dev)
 	val &= 0x3;
 
 	if (val < OCOTP_CFG3_SPEED_996MHZ)
-		if (dev_pm_opp_disable(dev, 996000000))
+		if (disable_freq_if_available(dev, 996000000))
 			dev_warn(dev, "failed to disable 996MHz OPP\n");
 
 	if (of_machine_is_compatible("fsl,imx6q") ||
 	    of_machine_is_compatible("fsl,imx6qp")) {
 		if (val != OCOTP_CFG3_SPEED_852MHZ)
-			if (dev_pm_opp_disable(dev, 852000000))
+			if (disable_freq_if_available(dev, 852000000))
 				dev_warn(dev, "failed to disable 852MHz OPP\n");
 		if (val != OCOTP_CFG3_SPEED_1P2GHZ)
-			if (dev_pm_opp_disable(dev, 1200000000))
+			if (disable_freq_if_available(dev, 1200000000))
 				dev_warn(dev, "failed to disable 1.2GHz OPP\n");
 	}
 
@@ -318,17 +333,17 @@ static int imx6ul_opp_check_speed_grading(struct device *dev)
 
 	if (of_machine_is_compatible("fsl,imx6ul")) {
 		if (val != OCOTP_CFG3_6UL_SPEED_696MHZ)
-			if (dev_pm_opp_disable(dev, 696000000))
+			if (disable_freq_if_available(dev, 696000000))
 				dev_warn(dev, "failed to disable 696MHz OPP\n");
 	}
 
 	if (of_machine_is_compatible("fsl,imx6ull")) {
 		if (val != OCOTP_CFG3_6ULL_SPEED_792MHZ)
-			if (dev_pm_opp_disable(dev, 792000000))
+			if (disable_freq_if_available(dev, 792000000))
 				dev_warn(dev, "failed to disable 792MHz OPP\n");
 
 		if (val != OCOTP_CFG3_6ULL_SPEED_900MHZ)
-			if (dev_pm_opp_disable(dev, 900000000))
+			if (disable_freq_if_available(dev, 900000000))
 				dev_warn(dev, "failed to disable 900MHz OPP\n");
 	}
 
-- 
2.11.0

Re: [PATCH] cpufreq: imx6q: Disable only available frequencies

[Viresh Kumar]

On 11-05-23, 11:23, Christoph Niedermaier wrote:
> In the example in Documentation/power/opp.rst, an availability check
> is present before disabling a specific frequency. If a frequency isn't
> available, the warning of a failed disabling of a non-existent
> frequency is misleading.

Which warning ?

-- 
viresh

Re: [PATCH] cpufreq: imx6q: Disable only available frequencies

[Viresh Kumar]

On 11-05-23, 11:23, Christoph Niedermaier wrote:
> @@ -254,16 +269,16 @@ static int imx6q_opp_check_speed_grading(struct device *dev)
>  	val &= 0x3;
>  
>  	if (val < OCOTP_CFG3_SPEED_996MHZ)
> -		if (dev_pm_opp_disable(dev, 996000000))
> +		if (disable_freq_if_available(dev, 996000000))
>  			dev_warn(dev, "failed to disable 996MHz OPP\n");

Ahh, these warnings.

What about printing the warning only when returned error != -ENODEV ?
Or just marking them dev_dbg() ?

-- 
viresh

RE: [PATCH] cpufreq: imx6q: Disable only available frequencies

[Christoph Niedermaier]

From: Viresh Kumar [mailto:viresh.kumar@linaro.org]
Sent: Thursday, May 11, 2023 11:54 AM
> On 11-05-23, 11:23, Christoph Niedermaier wrote:
>> @@ -254,16 +269,16 @@ static int imx6q_opp_check_speed_grading(struct device *dev)
>>       val &= 0x3;
>>
>>       if (val < OCOTP_CFG3_SPEED_996MHZ)
>> -             if (dev_pm_opp_disable(dev, 996000000))
>> +             if (disable_freq_if_available(dev, 996000000))
>>                       dev_warn(dev, "failed to disable 996MHz OPP\n");
> 
> Ahh, these warnings.
> 
> What about printing the warning only when returned error != -ENODEV ?
> Or just marking them dev_dbg() ?

I have kept to the documentation of opp, but if -ENODEV is possible
I prefer it. My suggestion is to change each "dev_pm_opp_disable" in
this way:

-	if (val < OCOTP_CFG3_SPEED_996MHZ)
-		if (dev_pm_opp_disable(dev, 996000000))
+	if (val < OCOTP_CFG3_SPEED_996MHZ) {
+		ret_opp = dev_pm_opp_disable(dev, 996000000);
+		if (ret_opp < 0 && ret_opp != -ENODEV)
 			dev_warn(dev, "failed to disable 996MHz OPP\n");
+	}

If that's OK, I can do a version 2 with it.


Regards
Christoph

Re: [PATCH] cpufreq: imx6q: Disable only available frequencies

[Viresh Kumar]

On 11-05-23, 14:38, Christoph Niedermaier wrote:
> -	if (val < OCOTP_CFG3_SPEED_996MHZ)
> -		if (dev_pm_opp_disable(dev, 996000000))
> +	if (val < OCOTP_CFG3_SPEED_996MHZ) {
> +		ret_opp = dev_pm_opp_disable(dev, 996000000);
> +		if (ret_opp < 0 && ret_opp != -ENODEV)
>  			dev_warn(dev, "failed to disable 996MHz OPP\n");
> +	}
> 
> If that's OK, I can do a version 2 with it.

Looks okay to me.

-- 
viresh

Re: [PATCH] cpufreq: imx6q: Disable only available frequencies

[Marek Vasut]

On 5/11/23 11:23, Christoph Niedermaier wrote:
> In the example in Documentation/power/opp.rst, an availability check
> is present before disabling a specific frequency. If a frequency isn't
> available, the warning of a failed disabling of a non-existent
> frequency is misleading. Therefore, check the availability of the
> frequency in a separate inline function before disabling it.

[...]

> diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
> index 48e1772e98fd..4e2d2bc47aba 100644
> --- a/drivers/cpufreq/imx6q-cpufreq.c
> +++ b/drivers/cpufreq/imx6q-cpufreq.c
> @@ -209,6 +209,21 @@ static struct cpufreq_driver imx6q_cpufreq_driver = {
>   	.suspend = cpufreq_generic_suspend,
>   };
>   
> +static inline int disable_freq_if_available(struct device *dev,

The inline isn't needed, esp. on static function, let the compiler 
figure it out.

Also, "disable if available" should rather be "disable if unavailable" I 
think ?

> +					    unsigned long freq)
> +{
> +	struct dev_pm_opp *opp;
> +	int ret = 0;
> +
> +	opp = dev_pm_opp_find_freq_exact(dev, freq, true);
> +	if (!IS_ERR(opp)) {
> +		dev_pm_opp_put(opp);
> +		ret = dev_pm_opp_disable(dev, freq);
> +	}
> +
> +	return ret;
> +}
> +
>   #define OCOTP_CFG3			0x440
>   #define OCOTP_CFG3_SPEED_SHIFT		16
>   #define OCOTP_CFG3_SPEED_1P2GHZ		0x3
> @@ -254,16 +269,16 @@ static int imx6q_opp_check_speed_grading(struct device *dev)
>   	val &= 0x3;
>   
>   	if (val < OCOTP_CFG3_SPEED_996MHZ)
> -		if (dev_pm_opp_disable(dev, 996000000))
> +		if (disable_freq_if_available(dev, 996000000))
>   			dev_warn(dev, "failed to disable 996MHz OPP\n");
>   
>   	if (of_machine_is_compatible("fsl,imx6q") ||
>   	    of_machine_is_compatible("fsl,imx6qp")) {

Can we introduce a function like:

void imx_disable_freq_if_unavailable(struct device *dev, u32 freq_mhz, 
u32 val, u32 mask)
{
    if (val == mask)
      return;
    if (!disable_freq_if_available(dev, freq_mhz * 1000000))
      return;
    dev_warn(dev, "failed to disable %dMHz OPP\n", mhz);
}

And then just call it multiple times in here, to reduce duplication ?

>   		if (val != OCOTP_CFG3_SPEED_852MHZ)
> -			if (dev_pm_opp_disable(dev, 852000000))
> +			if (disable_freq_if_available(dev, 852000000))
>   				dev_warn(dev, "failed to disable 852MHz OPP\n");

[...]

RE: [PATCH] cpufreq: imx6q: Disable only available frequencies

[Christoph Niedermaier]

From: Marek Vasut [mailto:marex@denx.de]
Sent: Thursday, May 11, 2023 9:26 PM
> On 5/11/23 11:23, Christoph Niedermaier wrote:
>> In the example in Documentation/power/opp.rst, an availability check
>> is present before disabling a specific frequency. If a frequency isn't
>> available, the warning of a failed disabling of a non-existent
>> frequency is misleading. Therefore, check the availability of the
>> frequency in a separate inline function before disabling it.
> 
> [...]
> 
>> diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
>> index 48e1772e98fd..4e2d2bc47aba 100644
>> --- a/drivers/cpufreq/imx6q-cpufreq.c
>> +++ b/drivers/cpufreq/imx6q-cpufreq.c
>> @@ -209,6 +209,21 @@ static struct cpufreq_driver imx6q_cpufreq_driver = {
>>       .suspend = cpufreq_generic_suspend,
>>   };
>>
>> +static inline int disable_freq_if_available(struct device *dev,
> 
> The inline isn't needed, esp. on static function, let the compiler
> figure it out.
> 
> Also, "disable if available" should rather be "disable if unavailable" I
> think ?

Here I mean the OPP and I can only disable an available frequency.

> 
>> +                                         unsigned long freq)
>> +{
>> +     struct dev_pm_opp *opp;
>> +     int ret = 0;
>> +
>> +     opp = dev_pm_opp_find_freq_exact(dev, freq, true);
>> +     if (!IS_ERR(opp)) {
>> +             dev_pm_opp_put(opp);
>> +             ret = dev_pm_opp_disable(dev, freq);
>> +     }
>> +
>> +     return ret;
>> +}
>> +
>>   #define OCOTP_CFG3                  0x440
>>   #define OCOTP_CFG3_SPEED_SHIFT              16
>>   #define OCOTP_CFG3_SPEED_1P2GHZ             0x3
>> @@ -254,16 +269,16 @@ static int imx6q_opp_check_speed_grading(struct device *dev)
>>       val &= 0x3;
>>
>>       if (val < OCOTP_CFG3_SPEED_996MHZ)
>> -             if (dev_pm_opp_disable(dev, 996000000))
>> +             if (disable_freq_if_available(dev, 996000000))
>>                       dev_warn(dev, "failed to disable 996MHz OPP\n");
>>
>>       if (of_machine_is_compatible("fsl,imx6q") ||
>>           of_machine_is_compatible("fsl,imx6qp")) {
> 
> Can we introduce a function like:
> 
> void imx_disable_freq_if_unavailable(struct device *dev, u32 freq_mhz,
> u32 val, u32 mask)
> {
>     if (val == mask)
>       return;
>     if (!disable_freq_if_available(dev, freq_mhz * 1000000))
>       return;
>     dev_warn(dev, "failed to disable %dMHz OPP\n", mhz);
> }
> 
> And then just call it multiple times in here, to reduce duplication ?
> 
>>               if (val != OCOTP_CFG3_SPEED_852MHZ)
>> -                     if (dev_pm_opp_disable(dev, 852000000))
>> +                     if (disable_freq_if_available(dev, 852000000))
>>                               dev_warn(dev, "failed to disable 852MHz OPP\n");
> 

Yes, using a function to reduce duplications would be good.


Regards
Christoph