Hi Durgadoss, Thanks for the detailed review comments. On 24 February 2012 16:34, R, Durgadoss <durgadoss.r@xxxxxxxxx> wrote: > Hi Amit, > >> -----Original Message----- >> From: amit kachhap [mailto:amitdanielk@xxxxxxxxx] On Behalf Of Amit Daniel >> Kachhap >> Sent: Wednesday, February 22, 2012 3:44 PM >> To: linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx >> Cc: linux-kernel@xxxxxxxxxxxxxxx; mjg59@xxxxxxxxxxxxx; linux- >> acpi@xxxxxxxxxxxxxxx; lenb@xxxxxxxxxx; linaro-dev@xxxxxxxxxxxxxxxx; >> amit.kachhap@xxxxxxxxxx; R, Durgadoss; rob.lee@xxxxxxxxxx; patches@xxxxxxxxxx >> Subject: [PATCH 2/4] thermal: Add generic cpufreq cooling implementation >> >> This patch adds support for generic cpu thermal cooling low level >> implementations using frequency scaling up/down based on the request >> from user. Different cpu related cooling devices can be registered by the > > I believe what you mean by 'user' is another Driver using this code.. right ?? Yes. > >> 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. The user of these api's are responsible for >> passing clipping frequency in percentages. >> >> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@xxxxxxxxxx> >> --- >> Documentation/thermal/cpu-cooling-api.txt | 40 ++++ >> drivers/thermal/Kconfig | 11 + >> drivers/thermal/Makefile | 1 + >> drivers/thermal/cpu_cooling.c | 310 +++++++++++++++++++++++++++++ >> include/linux/cpu_cooling.h | 54 +++++ >> 5 files changed, 416 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..04de67c >> --- /dev/null >> +++ b/Documentation/thermal/cpu-cooling-api.txt >> @@ -0,0 +1,40 @@ >> +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 point 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-%x". This api can support multiple instance of cpufreq >> cooling >> + devices. >> + >> + tab_ptr: The table containing the percentage of frequency to be clipped >> for >> + each cooling state. >> + .freq_clip_pctg: Percentage of frequency to be clipped for each allowed >> + cpus. >> + .polling_interval: polling interval for this cooling state. >> + tab_size: the total number of cooling state. > > Although I can understand that the table size is equal to > the total number of cooling states, it is better to name it 'num_cooling_states' > (or something) that means what it is.. Yes your idea makes more sense. Will accept it in the next version. > >> + mask_val: all the allowed cpu's where frequency clipping can happen. >> + >> +1.1.2 void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev) >> + >> + This interface function unregisters the "thermal-cpufreq-%x" cooling >> device. >> + >> + cdev: Cooling device pointer which has to be unregistered. >> 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..298f550 >> --- /dev/null >> +++ b/drivers/thermal/cpu_cooling.c >> @@ -0,0 +1,310 @@ >> +/* >> + * 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 > > Except the _idr methods, all the code is inside this #ifdef. > So, I think it is better to add this dependency in Kconfig, > and leave this code clean w/o many #ifdef's. ok > >> +struct cpufreq_cooling_device { >> + int id; >> + 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; >> + struct list_head node; >> +}; >> + >> +static LIST_HEAD(cooling_cpufreq_list); >> +static DEFINE_MUTEX(cooling_cpufreq_lock); >> +static DEFINE_IDR(cpufreq_idr); >> +static struct cpufreq_cooling_device *notify_cpufreq; > > Please move this after the DEFINE_PER_CPU. > Hard to notice here.. ok > >> +static DEFINE_PER_CPU(unsigned int, max_policy_freq); >> +#endif /*CONFIG_CPU_FREQ*/ >> + >> +static int get_idr(struct idr *idr, struct mutex *lock, int *id) >> +{ >> + int err; >> +again: >> + if (unlikely(idr_pre_get(idr, GFP_KERNEL) == 0)) >> + return -ENOMEM; >> + >> + if (lock) >> + mutex_lock(lock); >> + err = idr_get_new(idr, NULL, id); >> + if (lock) >> + mutex_unlock(lock); >> + if (unlikely(err == -EAGAIN)) >> + goto again; >> + else if (unlikely(err)) >> + return err; >> + >> + *id = *id & MAX_ID_MASK; >> + return 0; >> +} >> + >> +static void release_idr(struct idr *idr, struct mutex *lock, int id) >> +{ >> + if (lock) >> + mutex_lock(lock); >> + idr_remove(idr, id); >> + if (lock) >> + mutex_unlock(lock); >> +} >> + >> +#ifdef CONFIG_CPU_FREQ >> +/*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; > > Why not just do a return !cpufreq_get_policy(&policy, cpu); ok > >> +} >> + >> +static int cpufreq_apply_cooling(struct cpufreq_cooling_device >> *cpufreq_device, >> + unsigned long cooling_state) >> +{ >> + int cpuid, this_cpu = smp_processor_id(); >> + >> + if (!is_cpufreq_valid(this_cpu)) > > You are not using this_cpu anywhere else..so, directly use > Smp_processor_id() here.. > Ok agreed. >> + return 0; >> + >> + if (cooling_state > cpufreq_device->tab_size) >> + return -EINVAL; >> + >> + /*Check if last cooling level is same as current cooling level*/ > > Use either 'state' or 'level' in comments as well as the variable name > Makes it easy to read.. Ok, will use state. > >> + if (cpufreq_device->cpufreq_state == cooling_state) >> + return 0; >> + >> + cpufreq_device->cpufreq_state = cooling_state; >> + >> + /*cpufreq thermal notifier uses this cpufreq device pointer*/ >> + notify_cpufreq = cpufreq_device; >> + >> + 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 th_pctg = 0, level; >> + >> + if (event != CPUFREQ_ADJUST) >> + return 0; >> + >> + if (!notify_cpufreq) >> + return 0; > > Why not combine both if's with an || ? Ok > >> + >> + level = notify_cpufreq->cpufreq_state; > > Yes..here it is..please use level/state.. Ok, will use state > >> + >> + if (level > 0) { >> + th_table = >> + &(notify_cpufreq->tab_ptr[level - 1]); >> + th_pctg = th_table->freq_clip_pctg; >> + max_freq = >> + (policy->cpuinfo.max_freq * (100 - th_pctg)) / 100; >> + >> + if (per_cpu(max_policy_freq, policy->cpu) == 0) >> + per_cpu(max_policy_freq, policy->cpu) = policy->max; >> + } else { >> + if (per_cpu(max_policy_freq, policy->cpu) != 0) { >> + max_freq = per_cpu(max_policy_freq, policy->cpu); >> + per_cpu(max_policy_freq, policy->cpu) = 0; >> + } else { >> + max_freq = policy->max; >> + } >> + } >> + >> + 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) >> +{ >> + struct cpufreq_cooling_device *cpufreq_device = NULL; > > Why assigning NULL ? yes it is not needed. > >> + >> + mutex_lock(&cooling_cpufreq_lock); >> + list_for_each_entry(cpufreq_device, &cooling_cpufreq_list, node) >> + if (cpufreq_device && cpufreq_device->cool_dev == cdev) >> + break; >> + >> + mutex_unlock(&cooling_cpufreq_lock); >> + if (!cpufreq_device || cpufreq_device->cool_dev != cdev) >> + return -EINVAL; >> + >> + *state = cpufreq_device->tab_size; >> + return 0; >> +} > > The above can be simplified this way: > int ret = -EINVAL; > mutex_lock(&cooling_cpufreq_lock); > list_for_each_entry(cpufreq_device, &cooling_cpufreq_list, node) > if (cpufreq_device->cool_dev == cdev) { > *state = cpufreq_device->tab_size; > ret = 0; > break; > } > > mutex_unlock(&cooling_cpufreq_lock); > return ret; > > I think the same can be done for the get_ function below..and similar ones > in the patch 3/4. Ok accepted. > >> + >> +static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev, >> + unsigned long *state) >> +{ >> + struct cpufreq_cooling_device *cpufreq_device = NULL; >> + >> + mutex_lock(&cooling_cpufreq_lock); >> + list_for_each_entry(cpufreq_device, &cooling_cpufreq_list, node) >> + if (cpufreq_device && cpufreq_device->cool_dev == cdev) >> + break; >> + >> + mutex_unlock(&cooling_cpufreq_lock); >> + if (!cpufreq_device || cpufreq_device->cool_dev != cdev) >> + return -EINVAL; >> + *state = cpufreq_device->cpufreq_state; >> + return 0; >> +} >> + >> +/*This cooling may be as PASSIVE/ACTIVE type*/ >> +static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev, >> + unsigned long state) >> +{ >> + struct cpufreq_cooling_device *cpufreq_device = NULL; >> + >> + mutex_lock(&cooling_cpufreq_lock); >> + list_for_each_entry(cpufreq_device, &cooling_cpufreq_list, node) >> + if (cpufreq_device && cpufreq_device->cool_dev == cdev) >> + break; >> + >> + mutex_unlock(&cooling_cpufreq_lock); >> + if (!cpufreq_device || cpufreq_device->cool_dev != cdev) >> + return -EINVAL; >> + >> + cpufreq_apply_cooling(cpufreq_device, 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; >> + struct cpufreq_cooling_device *cpufreq_dev = NULL; >> + unsigned int count = 0; >> + char dev_name[THERMAL_NAME_LENGTH]; >> + int ret = 0, id = 0; >> + >> + if (tab_ptr == NULL || tab_size == 0) >> + return ERR_PTR(-EINVAL); >> + >> + list_for_each_entry(cpufreq_dev, &cooling_cpufreq_list, node) >> + count++; >> + >> + cpufreq_dev = >> + kzalloc(sizeof(struct cpufreq_cooling_device), GFP_KERNEL); >> + >> + if (!cpufreq_dev) >> + return ERR_PTR(-ENOMEM); >> + >> + cpufreq_dev->tab_ptr = tab_ptr; >> + cpufreq_dev->tab_size = tab_size; >> + cpufreq_dev->allowed_cpus = mask_val; >> + >> + ret = get_idr(&cpufreq_idr, &cooling_cpufreq_lock, &cpufreq_dev->id); >> + if (ret) { >> + kfree(cpufreq_dev); >> + return ERR_PTR(-EINVAL); >> + } >> + >> + sprintf(dev_name, "thermal-cpufreq-%d", cpufreq_dev->id); >> + >> + cool_dev = thermal_cooling_device_register(dev_name, cpufreq_dev, >> + &cpufreq_cooling_ops); >> + if (!cool_dev) { >> + release_idr(&cpufreq_idr, &cooling_cpufreq_lock, >> + cpufreq_dev->id); >> + kfree(cpufreq_dev); >> + return ERR_PTR(-EINVAL); >> + } >> + cpufreq_dev->id = id; >> + cpufreq_dev->cool_dev = cool_dev; >> + mutex_lock(&cooling_cpufreq_lock); >> + list_add_tail(&cpufreq_dev->node, &cooling_cpufreq_list); >> + mutex_unlock(&cooling_cpufreq_lock); >> + >> + if (count == 0) >> + cpufreq_register_notifier(&thermal_cpufreq_notifier_block, >> + CPUFREQ_POLICY_NOTIFIER); > > Why do we register only when count is 0 ? > Or should this be 'if (count > 0)' ? Count represents the number of cpufreq type cooling devices. So for the first call of this API , cpufreq_register_notifier is called. Other call to cpufreq_cooling_register will use the same notifier. May be using bool flag instead of count variable is better. > >> + return cool_dev; >> +} >> +EXPORT_SYMBOL(cpufreq_cooling_register); >> + >> +void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev) >> +{ >> + struct cpufreq_cooling_device *cpufreq_dev = NULL; >> + unsigned int count = 0; >> + >> + mutex_lock(&cooling_cpufreq_lock); >> + list_for_each_entry(cpufreq_dev, &cooling_cpufreq_list, node) { >> + if (cpufreq_dev && cpufreq_dev->cool_dev == cdev) >> + break; >> + count++; >> + } >> + >> + if (!cpufreq_dev || cpufreq_dev->cool_dev != cdev) { >> + mutex_unlock(&cooling_cpufreq_lock); >> + return; >> + } >> + >> + list_del(&cpufreq_dev->node); >> + mutex_unlock(&cooling_cpufreq_lock); >> + >> + if (count == 1) > > Same here..I do not get the idea behind this.. > Shouldn't this be 'if (count > 0)' ? Same as above. > > In general, > I would like to see a real driver using these API's. This will help > everybody to understand the working of these API's much better. Actually RFC version of the driver is already posted which uses these api's. (https://lkml.org/lkml/2011/12/21/169). I forgot to add this link in this patchset. I will post the new version of the driver shortly. > > Thanks, > Durga > >> + cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block, >> + CPUFREQ_POLICY_NOTIFIER); >> + >> + thermal_cooling_device_unregister(cpufreq_dev->cool_dev); >> + release_idr(&cpufreq_idr, &cooling_cpufreq_lock, cpufreq_dev->id); >> + kfree(cpufreq_dev); >> +} >> +EXPORT_SYMBOL(cpufreq_cooling_unregister); >> +#endif /*CONFIG_CPU_FREQ*/ >> diff --git a/include/linux/cpu_cooling.h b/include/linux/cpu_cooling.h >> new file mode 100644 >> index 0000000..5dc5632 >> --- /dev/null >> +++ b/include/linux/cpu_cooling.h >> @@ -0,0 +1,54 @@ >> +/* >> + * 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; >> + unsigned int polling_interval; >> +}; >> + >> +#ifdef CONFIG_CPU_FREQ >> +struct thermal_cooling_device *cpufreq_cooling_register( >> + struct freq_pctg_table *tab_ptr, unsigned int tab_size, >> + const struct cpumask *mask_val); >> + >> +void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev); >> +#else /*!CONFIG_CPU_FREQ*/ >> +static inline struct thermal_cooling_device *cpufreq_cooling_register( >> + struct freq_pctg_table *tab_ptr, unsigned int tab_size, >> + const struct cpumask *mask_val) >> +{ >> + return NULL; >> +} >> +static inline void cpufreq_cooling_unregister( >> + struct thermal_cooling_device *cdev) >> +{ >> + return; >> +} >> +#endif /*CONFIG_CPU_FREQ*/ >> + >> +#endif /* __CPU_COOLING_H__ */ >> -- >> 1.7.1 > _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/linux-pm
