Re: [PATCH V2 4/7] thermal/drivers/Kconfig: Convert the CPU cooling device to a choice

From: Viresh Kumar
Date: Fri Feb 23 2018 - 00:24:29 EST


On 21-02-18, 16:29, Daniel Lezcano wrote:
> The next changes will add new way to cool down a CPU. In order to
> sanitize and make the overall cpu cooling code consistent and robust
> we must prevent the cpu cooling devices to co-exists with the same
> purpose at the same time in the kernel.
>
> Make the CPU cooling device a choice in the Kconfig, so only one CPU
> cooling strategy can be chosen.

Daniel T. already raised his concern (which I share too) about the
multi-platform builds, where we would want this to be runtime
selectable. I am fine with your approach of making that possible later
on, but I would really like that to be merged before the combo thing
comes in. So, I would suggest to merge stuff in this order:

- this series
- runtime selectable strategy
- combo stuff

I hope that would be fine ?

> Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
> ---
> drivers/thermal/Kconfig | 20 +++++++++++++++++---
> drivers/thermal/cpu_cooling.c | 2 ++
> include/linux/cpu_cooling.h | 6 +++---
> 3 files changed, 22 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index b6adc54..5aaae1b 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -142,17 +142,31 @@ config THERMAL_GOV_POWER_ALLOCATOR
> allocating and limiting power to devices.
>
> config CPU_THERMAL
> - bool "generic cpu cooling support"
> - depends on CPU_FREQ
> + bool "Generic cpu cooling support"
> depends on THERMAL_OF
> help
> + Enable the CPU cooling features. If the system has no active
> + cooling device available, this option allows to use the CPU
> + as a cooling device.
> +
> +choice
> + prompt "CPU cooling strategies"
> + depends on CPU_THERMAL
> + default CPU_FREQ_THERMAL
> + help
> + Select the CPU cooling strategy.
> +
> +config CPU_FREQ_THERMAL
> + bool "CPU frequency cooling strategy"
> + depends on CPU_FREQ
> + help
> This implements the generic cpu cooling mechanism through frequency
> reduction. An ACPI version of this already exists
> (drivers/acpi/processor_thermal.c).
> This will be useful for platforms using the generic thermal interface
> and not the ACPI interface.
>
> - If you want this support, you should say Y here.

Should this line be moved to the CPU_THERMAL section above ?

> +endchoice
>
> config CLOCK_THERMAL
> bool "Generic clock cooling support"
> diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
> index 7bdc19f..5c219dc 100644
> --- a/drivers/thermal/cpu_cooling.c
> +++ b/drivers/thermal/cpu_cooling.c
> @@ -22,6 +22,7 @@
>
> #include <trace/events/thermal.h>
>
> +#ifdef CONFIG_CPU_FREQ_THERMAL
> /*
> * Cooling state <-> CPUFreq frequency
> *
> @@ -926,3 +927,4 @@ void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
> kfree(cpufreq_cdev);
> }
> EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister);
> +#endif /* CONFIG_CPU_FREQ_THERMAL */
> diff --git a/include/linux/cpu_cooling.h b/include/linux/cpu_cooling.h
> index d4292eb..c0accc7 100644
> --- a/include/linux/cpu_cooling.h
> +++ b/include/linux/cpu_cooling.h
> @@ -33,7 +33,7 @@ struct cpufreq_policy;
> typedef int (*get_static_t)(cpumask_t *cpumask, int interval,
> unsigned long voltage, u32 *power);
>
> -#ifdef CONFIG_CPU_THERMAL
> +#ifdef CONFIG_CPU_FREQ_THERMAL
> /**
> * cpufreq_cooling_register - function to create cpufreq cooling device.
> * @policy: cpufreq policy.
> @@ -84,7 +84,7 @@ of_cpufreq_power_cooling_register(struct device_node *np,
> */
> void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev);
>
> -#else /* !CONFIG_CPU_THERMAL */
> +#else /* !CONFIG_CPU_FREQ_THERMAL */
> static inline struct thermal_cooling_device *
> cpufreq_cooling_register(struct cpufreq_policy *policy)
> {
> @@ -118,6 +118,6 @@ void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
> {
> return;
> }
> -#endif /* CONFIG_CPU_THERMAL */
> +#endif /* CONFIG_CPU_FREQ_THERMAL */
>
> #endif /* __CPU_COOLING_H__ */

drivers/cpufreq/Kconfig: # if CPU_THERMAL is on and THERMAL=m, CPUFREQ_DT cannot be =y:
drivers/cpufreq/Kconfig: depends on !CPU_THERMAL || THERMAL
drivers/cpufreq/Kconfig: depends on !CPU_THERMAL || THERMAL
drivers/cpufreq/Kconfig.arm: # if CPU_THERMAL is on and THERMAL=m, ARM_BIT_LITTLE_CPUFREQ cannot be =y
drivers/cpufreq/Kconfig.arm: depends on !CPU_THERMAL || THERMAL
drivers/cpufreq/Kconfig.arm: depends on !CPU_THERMAL || THERMAL

All of these need to use CPU_FREQ_THERMAL now.

include/trace/events/thermal.h:#ifdef CONFIG_CPU_THERMAL
include/trace/events/thermal.h:#endif /* CONFIG_CPU_THERMAL */

And this too.

--
viresh