Hello Amit, On Tue, Feb 07, 2012 at 10:21:15AM -0800, Amit Kachhap wrote: > Hi eduardo, > > Again thanks for the review. > > On 7 February 2012 00:25, Eduardo Valentin <eduardo.valentin@xxxxxx> wrote: > > Hello Amit, > > > > On Tue, Dec 13, 2011 at 08:43:16PM +0530, Amit Daniel Kachhap wrote: > >> This patch adds support for generic cpu thermal cooling low level > >> implementations using frequency scaling and cpuhotplugg currently. > >> Different cpu related cooling devices can be registered by the > >> user and the binding of these cooling devices to the corresponding > >> trip points can be easily done as the registration API's return the > >> cooling device pointer. > >> > >> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@xxxxxxxxxx> > >> --- > >> Documentation/thermal/cpu-cooling-api.txt | 52 +++++ > >> drivers/thermal/Kconfig | 11 + > >> drivers/thermal/Makefile | 1 + > >> drivers/thermal/cpu_cooling.c | 302 +++++++++++++++++++++++++++++ > >> include/linux/cpu_cooling.h | 45 +++++ > >> 5 files changed, 411 insertions(+), 0 deletions(-) > >> create mode 100644 Documentation/thermal/cpu-cooling-api.txt > >> create mode 100644 drivers/thermal/cpu_cooling.c > >> create mode 100644 include/linux/cpu_cooling.h > >> > >> diff --git a/Documentation/thermal/cpu-cooling-api.txt b/Documentation/thermal/cpu-cooling-api.txt > >> new file mode 100644 > >> index 0000000..d30b4f2 > >> --- /dev/null > >> +++ b/Documentation/thermal/cpu-cooling-api.txt > >> @@ -0,0 +1,52 @@ > >> +CPU cooling api's How To > >> +=================================== > >> + > >> +Written by Amit Daniel Kachhap <amit.kachhap@xxxxxxxxxx> > >> + > >> +Updated: 13 Dec 2011 > >> + > >> +Copyright (c) 2011 Samsung Electronics Co., Ltd(http://www.samsung.com) > >> + > >> +0. Introduction > >> + > >> +The generic cpu cooling(freq clipping, cpuhotplug) provides > >> +registration/unregistration api's to the user. The binding of the cooling > >> +devices to the trip types is left for the user. The registration api's returns > >> +the cooling device pointer. > >> + > >> +1. cpufreq cooling api's > >> + > >> +1.1 cpufreq registration api's > >> +1.1.1 struct thermal_cooling_device *cpufreq_cooling_register( > >> + struct freq_pctg_table *tab_ptr, unsigned int tab_size, > >> + const struct cpumask *mask_val) > >> + > >> + This interface function registers the cpufreq cooling device with the name > >> + "thermal-cpufreq". > >> + > >> + tab_ptr: The table containing the percentage of frequency to be clipped for > >> + each cooling state. > >> + .freq_clip_pctg[NR_CPUS]:Percentage of frequency to be clipped for each > >> + cpu. > >> + .polling_interval: polling interval for this cooling state. > >> + tab_size: the total number of cooling state. > >> + mask_val: all the allowed cpu's where frequency clipping can happen. > >> + > >> +1.1.2 void cpufreq_cooling_unregister(void) > >> + > >> + This interface function unregisters the "thermal-cpufreq" cooling device. > >> + > >> + > >> +1.2 cpuhotplug registration api's > >> + > >> +1.2.1 struct thermal_cooling_device *cpuhotplug_cooling_register( > >> + const struct cpumask *mask_val) > >> + > >> + This interface function registers the cpuhotplug cooling device with the name > >> + "thermal-cpuhotplug". > >> + > >> + mask_val: all the allowed cpu's which can be hotplugged out. > >> + > >> +1.1.2 void cpuhotplug_cooling_unregister(void) > >> + > >> + This interface function unregisters the "thermal-cpuhotplug" cooling device. > >> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig > >> index f7f71b2..298c1cd 100644 > >> --- a/drivers/thermal/Kconfig > >> +++ b/drivers/thermal/Kconfig > >> @@ -18,3 +18,14 @@ config THERMAL_HWMON > >> depends on THERMAL > >> depends on HWMON=y || HWMON=THERMAL > >> default y > >> + > >> +config CPU_THERMAL > >> + bool "generic cpu cooling support" > >> + depends on THERMAL > >> + help > >> + This implements the generic cpu cooling mechanism through frequency > >> + reduction, cpu hotplug and any other ways of reducing temperature. 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 or M here. > >> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile > >> index 31108a0..655cbc4 100644 > >> --- a/drivers/thermal/Makefile > >> +++ b/drivers/thermal/Makefile > >> @@ -3,3 +3,4 @@ > >> # > >> > >> obj-$(CONFIG_THERMAL) += thermal_sys.o > >> +obj-$(CONFIG_CPU_THERMAL) += cpu_cooling.o > >> diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c > >> new file mode 100644 > >> index 0000000..cdd148c > >> --- /dev/null > >> +++ b/drivers/thermal/cpu_cooling.c > >> @@ -0,0 +1,302 @@ > >> +/* > >> + * linux/drivers/thermal/cpu_cooling.c > >> + * > >> + * Copyright (C) 2011 Samsung Electronics Co., Ltd(http://www.samsung.com) > >> + * Copyright (C) 2011 Amit Daniel <amit.kachhap@xxxxxxxxxx> > >> + * > >> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > >> + * This program is free software; you can redistribute it and/or modify > >> + * it under the terms of the GNU General Public License as published by > >> + * the Free Software Foundation; version 2 of the License. > >> + * > >> + * This program is distributed in the hope that it will be useful, but > >> + * WITHOUT ANY WARRANTY; without even the implied warranty of > >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > >> + * General Public License for more details. > >> + * > >> + * You should have received a copy of the GNU General Public License along > >> + * with this program; if not, write to the Free Software Foundation, Inc., > >> + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. > >> + * > >> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > >> + */ > >> +#include <linux/kernel.h> > >> +#include <linux/module.h> > >> +#include <linux/thermal.h> > >> +#include <linux/platform_device.h> > >> +#include <linux/cpufreq.h> > >> +#include <linux/err.h> > >> +#include <linux/slab.h> > >> +#include <linux/cpu.h> > >> +#include <linux/cpu_cooling.h> > >> + > >> +#ifdef CONFIG_CPU_FREQ > >> +struct cpufreq_cooling_device { > >> + struct thermal_cooling_device *cool_dev; > >> + struct freq_pctg_table *tab_ptr; > >> + unsigned int tab_size; > >> + unsigned int cpufreq_state; > >> + const struct cpumask *allowed_cpus; > >> +}; > >> + > >> +static struct cpufreq_cooling_device *cpufreq_device; > >> + > >> +/*Below codes defines functions to be used for cpufreq as cooling device*/ > >> +static bool is_cpufreq_valid(int cpu) > >> +{ > >> + struct cpufreq_policy policy; > >> + if (!cpufreq_get_policy(&policy, cpu)) > >> + return true; > >> + return false; > >> +} > >> + > >> +static int cpufreq_apply_cooling(int cooling_state) > >> +{ > > > > Why do you need cooling_state to be signed? You used it always against > > unsigned values. Besides, the thermal api imposes unsigned long. > Yes, unsigned long is a better way. > > > >> + int cpuid, this_cpu = smp_processor_id(); > >> + > >> + if (!is_cpufreq_valid(this_cpu)) > >> + return 0; > >> + > >> + if (cooling_state > cpufreq_device->tab_size) > >> + return -EINVAL; > >> + > >> + /*Check if last cooling level is same as current cooling level*/ > >> + if (cpufreq_device->cpufreq_state == cooling_state) > >> + return 0; > >> + > >> + cpufreq_device->cpufreq_state = cooling_state; > >> + > >> + for_each_cpu(cpuid, cpufreq_device->allowed_cpus) { > >> + if (is_cpufreq_valid(cpuid)) > >> + cpufreq_update_policy(cpuid); > >> + } > >> + > >> + return 0; > >> +} > >> + > >> +static int thermal_cpufreq_notifier(struct notifier_block *nb, > >> + unsigned long event, void *data) > >> +{ > >> + struct cpufreq_policy *policy = data; > >> + struct freq_pctg_table *th_table; > >> + unsigned long max_freq = 0; > >> + unsigned int cpu = policy->cpu, th_pctg = 0, level; > >> + > >> + if (event != CPUFREQ_ADJUST) > >> + return 0; > >> + > >> + level = cpufreq_device->cpufreq_state; > >> + > >> + if (level > 0) { > >> + th_table = > >> + &(cpufreq_device->tab_ptr[level - 1]); > >> + th_pctg = th_table->freq_clip_pctg[cpu]; > >> + } > >> + > >> + max_freq = > >> + (policy->cpuinfo.max_freq * (100 - th_pctg)) / 100; > > > > > > Might be interesting to extend this a bit. You could have the > > above as default policy setup, but you could also allow people > > to change this behavior. For instance, adding some callback option > > while registering the cooling device (or a notifier), which would > > determine the max_freq for the generic layer. The mechanism to > > deploy max_freq into the system must be generic enough with cpufreq > > APIs, but the decision to which max_freq to use, could be specific. > > Don't you think? > I agree that there will always some constraints on the system to cap > the max frequency. But these thermal clippings is called for rare > scenarios. Anyway, Your idea is worth considering. I will check if > cpufreq has any generic way of achieving this. Yeah, well, the idea was to have the max_freq value coming from some registered callback in your code, not really on cpufreq. > > > >> + > >> + cpufreq_verify_within_limits(policy, 0, max_freq); > >> + > >> + return 0; > >> +} > >> + > >> +/* > >> + * cpufreq cooling device callback functions > >> + */ > >> +static int cpufreq_get_max_state(struct thermal_cooling_device *cdev, > >> + unsigned long *state) > >> +{ > >> + *state = cpufreq_device->tab_size; > >> + return 0; > >> +} > >> + > >> +static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev, > >> + unsigned long *state) > >> +{ > >> + *state = cpufreq_device->cpufreq_state; > >> + return 0; > >> +} > >> + > >> +/*This cooling may be as PASSIVE/STATE_ACTIVE type*/ > >> +static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev, > >> + unsigned long state) > >> +{ > >> + cpufreq_apply_cooling(state); > >> + return 0; > >> +} > >> + > >> +/* bind cpufreq callbacks to cpufreq cooling device */ > >> +static struct thermal_cooling_device_ops cpufreq_cooling_ops = { > >> + .get_max_state = cpufreq_get_max_state, > >> + .get_cur_state = cpufreq_get_cur_state, > >> + .set_cur_state = cpufreq_set_cur_state, > >> +}; > >> + > >> +static struct notifier_block thermal_cpufreq_notifier_block = { > >> + .notifier_call = thermal_cpufreq_notifier, > >> +}; > >> + > >> +struct thermal_cooling_device *cpufreq_cooling_register( > >> + struct freq_pctg_table *tab_ptr, unsigned int tab_size, > >> + const struct cpumask *mask_val) > >> +{ > >> + struct thermal_cooling_device *cool_dev; > >> + > >> + if (tab_ptr == NULL || tab_size == 0) > >> + return ERR_PTR(-EINVAL); > >> + > >> + cpufreq_device = > >> + kzalloc(sizeof(struct cpufreq_cooling_device), GFP_KERNEL); > >> + > >> + if (!cpufreq_device) > >> + return ERR_PTR(-ENOMEM); > >> + > >> + cool_dev = thermal_cooling_device_register("thermal-cpufreq", NULL, > >> + &cpufreq_cooling_ops); > >> + if (!cool_dev) { > >> + kfree(cpufreq_device); > >> + return ERR_PTR(-EINVAL); > >> + } > >> + > >> + cpufreq_device->tab_ptr = tab_ptr; > >> + cpufreq_device->tab_size = tab_size; > >> + cpufreq_device->cool_dev = cool_dev; > >> + cpufreq_device->allowed_cpus = mask_val; > >> + > >> + cpufreq_register_notifier(&thermal_cpufreq_notifier_block, > >> + CPUFREQ_POLICY_NOTIFIER); > >> + return cool_dev; > >> +} > >> +EXPORT_SYMBOL(cpufreq_cooling_register); > >> + > >> +void cpufreq_cooling_unregister(void) > >> +{ > >> + cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block, > >> + CPUFREQ_POLICY_NOTIFIER); > >> + thermal_cooling_device_unregister(cpufreq_device->cool_dev); > >> + kfree(cpufreq_device); > >> +} > >> +EXPORT_SYMBOL(cpufreq_cooling_unregister); > >> +#else /*!CONFIG_CPU_FREQ*/ > >> +struct thermal_cooling_device *cpufreq_cooling_register( > >> + struct freq_pctg_table *tab_ptr, unsigned int tab_size) > >> +{ > >> + return NULL; > >> +} > >> +EXPORT_SYMBOL(cpufreq_cooling_register); > >> +void cpufreq_cooling_unregister(void) > >> +{ > >> + return; > >> +} > >> +EXPORT_SYMBOL(cpufreq_cooling_unregister); > >> +#endif /*CONFIG_CPU_FREQ*/ > >> + > >> +#ifdef CONFIG_HOTPLUG_CPU > >> + > >> +struct hotplug_cooling_device { > >> + struct thermal_cooling_device *cool_dev; > >> + unsigned int hotplug_state; > >> + const struct cpumask *allowed_cpus; > >> +}; > >> +static struct hotplug_cooling_device *hotplug_device; > >> + > >> +/* > >> + * cpu hotplug cooling device callback functions > >> + */ > >> +static int cpuhotplug_get_max_state(struct thermal_cooling_device *cdev, > >> + unsigned long *state) > >> +{ > >> + *state = 1; > >> + return 0; > >> +} > >> + > >> +static int cpuhotplug_get_cur_state(struct thermal_cooling_device *cdev, > >> + unsigned long *state) > >> +{ > >> + /*This cooling device may be of type ACTIVE, so state field > >> + can be 0 or 1*/ > >> + *state = hotplug_device->hotplug_state; > >> + return 0; > >> +} > >> + > >> +/*This cooling may be as PASSIVE/STATE_ACTIVE type*/ > >> +static int cpuhotplug_set_cur_state(struct thermal_cooling_device *cdev, > >> + unsigned long state) > >> +{ > >> + int cpuid, this_cpu = smp_processor_id(); > >> + > >> + if (hotplug_device->hotplug_state == state) > >> + return 0; > >> + > >> + /*This cooling device may be of type ACTIVE, so state field > >> + can be 0 or 1*/ > > > > /* > > * Small thing. Check the style for multi line comments. > > * This is also an example. > > */ > Ok. > > > >> + if (state == 1) { > >> + for_each_cpu(cpuid, hotplug_device->allowed_cpus) { > >> + if (cpu_online(cpuid) && (cpuid != this_cpu)) > >> + cpu_down(cpuid); > >> + } > >> + } else if (state == 0) { > >> + for_each_cpu(cpuid, hotplug_device->allowed_cpus) { > >> + if (!cpu_online(cpuid) && (cpuid != this_cpu)) > >> + cpu_up(cpuid); > >> + } > >> + } else > >> + return -EINVAL; > >> + > >> + hotplug_device->hotplug_state = state; > >> + > >> + return 0; > >> +} > >> +/* bind hotplug callbacks to cpu hotplug cooling device */ > >> +static struct thermal_cooling_device_ops cpuhotplug_cooling_ops = { > >> + .get_max_state = cpuhotplug_get_max_state, > >> + .get_cur_state = cpuhotplug_get_cur_state, > >> + .set_cur_state = cpuhotplug_set_cur_state, > >> +}; > >> + > >> +struct thermal_cooling_device *cpuhotplug_cooling_register( > >> + const struct cpumask *mask_val) > >> +{ > >> + struct thermal_cooling_device *cool_dev; > >> + > >> + hotplug_device = > >> + kzalloc(sizeof(struct hotplug_cooling_device), GFP_KERNEL); > >> + > >> + if (!hotplug_device) > >> + return ERR_PTR(-ENOMEM); > >> + > >> + cool_dev = thermal_cooling_device_register("thermal-cpuhotplug", NULL, > >> + &cpuhotplug_cooling_ops); > >> + if (!cool_dev) { > >> + kfree(hotplug_device); > >> + return ERR_PTR(-EINVAL); > >> + } > >> + > >> + hotplug_device->cool_dev = cool_dev; > >> + hotplug_device->hotplug_state = 0; > >> + hotplug_device->allowed_cpus = mask_val; > >> + > >> + return cool_dev; > >> +} > >> +EXPORT_SYMBOL(cpuhotplug_cooling_register); > >> + > >> +void cpuhotplug_cooling_unregister(void) > >> +{ > >> + thermal_cooling_device_unregister(hotplug_device->cool_dev); > >> + kfree(hotplug_device); > >> +} > >> +EXPORT_SYMBOL(cpuhotplug_cooling_unregister); > >> +#else /*!CONFIG_HOTPLUG_CPU*/ > >> +struct thermal_cooling_device *cpuhotplug_cooling_register( > >> + const struct cpumask *mask_val) > >> +{ > >> + return NULL; > >> +} > >> +EXPORT_SYMBOL(cpuhotplug_cooling_register); > >> +void cpuhotplug_cooling_unregister(void) > >> +{ > >> + return; > >> +} > >> +EXPORT_SYMBOL(cpuhotplug_cooling_unregister); > >> +#endif /*CONFIG_HOTPLUG_CPU*/ > >> diff --git a/include/linux/cpu_cooling.h b/include/linux/cpu_cooling.h > >> new file mode 100644 > >> index 0000000..0c57375 > >> --- /dev/null > >> +++ b/include/linux/cpu_cooling.h > >> @@ -0,0 +1,45 @@ > >> +/* > >> + * linux/include/linux/cpu_cooling.h > >> + * > >> + * Copyright (C) 2011 Samsung Electronics Co., Ltd(http://www.samsung.com) > >> + * Copyright (C) 2011 Amit Daniel <amit.kachhap@xxxxxxxxxx> > >> + * > >> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > >> + * This program is free software; you can redistribute it and/or modify > >> + * it under the terms of the GNU General Public License as published by > >> + * the Free Software Foundation; version 2 of the License. > >> + * > >> + * This program is distributed in the hope that it will be useful, but > >> + * WITHOUT ANY WARRANTY; without even the implied warranty of > >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > >> + * General Public License for more details. > >> + * > >> + * You should have received a copy of the GNU General Public License along > >> + * with this program; if not, write to the Free Software Foundation, Inc., > >> + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. > >> + * > >> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > >> + */ > >> + > >> +#ifndef __CPU_COOLING_H__ > >> +#define __CPU_COOLING_H__ > >> + > >> +#include <linux/thermal.h> > >> + > >> +struct freq_pctg_table { > >> + unsigned int freq_clip_pctg[NR_CPUS]; > >> + unsigned int polling_interval; > >> +}; > >> + > >> +extern struct thermal_cooling_device *cpufreq_cooling_register( > >> + struct freq_pctg_table *tab_ptr, unsigned int tab_size, > >> + const struct cpumask *mask_val); > > > > I suppose your original idea was to have this function called only once right? > > I'd suggest to add some documentation on this header file to specify this. > > > > Besides, the fact that you receive a cpumask may suggest you could register > > different cooling device for subsets of your system cpus. > > > > In any case, if you call this function more than once, you may end with memory leaks > > and the last call will be the one acting in the system. > > > yes these api's are meant to be called once. I am working on a new > version where all these function will be multi-instance and hence > different cpus can support different frequency clipping. OK. Another point, is about the fact that this implementation is clipping the frequency silently. I mean, by changing the policy.max_freq, we may conflict with what the user defines as max freq. > > > > > >> + > >> +extern void cpufreq_cooling_unregister(void); > >> + > >> +extern struct thermal_cooling_device *cpuhotplug_cooling_register( > >> + const struct cpumask *mask_val); > >> + > >> +extern void cpuhotplug_cooling_unregister(void); > >> + > >> +#endif /* __CPU_COOLING_H__ */ > > > > Another thing, I have the impression that solving the config selection in the > > header file instead of in .c files is cleaner. If you want to solve the config > > selection in .c files, better to do so with Makefiles. > > > > If you keep the ifdefery ( THERMAL vs. HOTPLUG_CPU vs. CPU_FREQ ) here in the > > header file, it is easier to read. > Ok will move them in .h > > > >> -- > >> 1.7.1 > >> > >> _______________________________________________ > >> linux-pm mailing list > >> linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx > >> https://lists.linuxfoundation.org/mailman/listinfo/linux-pm -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
