From e33df1d2f3a0141cd79e770f31999ba0dd7ebfa8 Mon Sep 17 00:00:00 2001 From: Javi Merino Date: Thu, 26 Feb 2015 19:00:27 +0000 Subject: [PATCH] thermal: let governors have private data for each thermal zone A governor may need to store its current state between calls to throttle(). That state depends on the thermal zone, so store it as private data in struct thermal_zone_device. The governors may have two new ops: bind_to_tz() and unbind_from_tz(). When provided, these functions let governors do some initialization and teardown when they are bound/unbound to a tz and possibly store that information in the governor_data field of the struct thermal_zone_device. Cc: Zhang Rui Cc: Eduardo Valentin Signed-off-by: Javi Merino Signed-off-by: Eduardo Valentin --- drivers/thermal/thermal_core.c | 83 ++++++++++++++++++++++++++++++---- include/linux/thermal.h | 9 ++++ 2 files changed, 84 insertions(+), 8 deletions(-) diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c index 605d6919c1b6..be62b1622ed3 100644 --- a/drivers/thermal/thermal_core.c +++ b/drivers/thermal/thermal_core.c @@ -75,6 +75,58 @@ static struct thermal_governor *__find_governor(const char *name) return NULL; } +/** + * bind_previous_governor() - bind the previous governor of the thermal zone + * @tz: a valid pointer to a struct thermal_zone_device + * @failed_gov_name: the name of the governor that failed to register + * + * Register the previous governor of the thermal zone after a new + * governor has failed to be bound. + */ +static void bind_previous_governor(struct thermal_zone_device *tz, + const char *failed_gov_name) +{ + if (tz->governor && tz->governor->bind_to_tz) { + if (tz->governor->bind_to_tz(tz)) { + dev_err(&tz->device, + "governor %s failed to bind and the previous one (%s) failed to bind again, thermal zone %s has no governor\n", + failed_gov_name, tz->governor->name, tz->type); + tz->governor = NULL; + } + } +} + +/** + * thermal_set_governor() - Switch to another governor + * @tz: a valid pointer to a struct thermal_zone_device + * @new_gov: pointer to the new governor + * + * Change the governor of thermal zone @tz. + * + * Return: 0 on success, an error if the new governor's bind_to_tz() failed. + */ +static int thermal_set_governor(struct thermal_zone_device *tz, + struct thermal_governor *new_gov) +{ + int ret = 0; + + if (tz->governor && tz->governor->unbind_from_tz) + tz->governor->unbind_from_tz(tz); + + if (new_gov && new_gov->bind_to_tz) { + ret = new_gov->bind_to_tz(tz); + if (ret) { + bind_previous_governor(tz, new_gov->name); + + return ret; + } + } + + tz->governor = new_gov; + + return ret; +} + int thermal_register_governor(struct thermal_governor *governor) { int err; @@ -107,8 +159,15 @@ int thermal_register_governor(struct thermal_governor *governor) name = pos->tzp->governor_name; - if (!strncasecmp(name, governor->name, THERMAL_NAME_LENGTH)) - pos->governor = governor; + if (!strncasecmp(name, governor->name, THERMAL_NAME_LENGTH)) { + int ret; + + ret = thermal_set_governor(pos, governor); + if (ret) + dev_err(&pos->device, + "Failed to set governor %s for thermal zone %s: %d\n", + governor->name, pos->type, ret); + } } mutex_unlock(&thermal_list_lock); @@ -134,7 +193,7 @@ void thermal_unregister_governor(struct thermal_governor *governor) list_for_each_entry(pos, &thermal_tz_list, node) { if (!strncasecmp(pos->governor->name, governor->name, THERMAL_NAME_LENGTH)) - pos->governor = NULL; + thermal_set_governor(pos, NULL); } mutex_unlock(&thermal_list_lock); @@ -770,8 +829,9 @@ policy_store(struct device *dev, struct device_attribute *attr, if (!gov) goto exit; - tz->governor = gov; - ret = count; + ret = thermal_set_governor(tz, gov); + if (!ret) + ret = count; exit: mutex_unlock(&tz->lock); @@ -1512,6 +1572,7 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type, int result; int count; int passive = 0; + struct thermal_governor *governor; if (type && strlen(type) >= THERMAL_NAME_LENGTH) return ERR_PTR(-EINVAL); @@ -1602,9 +1663,15 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type, mutex_lock(&thermal_governor_lock); if (tz->tzp) - tz->governor = __find_governor(tz->tzp->governor_name); + governor = __find_governor(tz->tzp->governor_name); else - tz->governor = def_governor; + governor = def_governor; + + result = thermal_set_governor(tz, governor); + if (result) { + mutex_unlock(&thermal_governor_lock); + goto unregister; + } mutex_unlock(&thermal_governor_lock); @@ -1693,7 +1760,7 @@ void thermal_zone_device_unregister(struct thermal_zone_device *tz) device_remove_file(&tz->device, &dev_attr_mode); device_remove_file(&tz->device, &dev_attr_policy); remove_trip_attrs(tz); - tz->governor = NULL; + thermal_set_governor(tz, NULL); thermal_remove_hwmon_sysfs(tz); release_idr(&thermal_tz_idr, &thermal_idr_lock, tz->id); diff --git a/include/linux/thermal.h b/include/linux/thermal.h index bac0f52c7a1e..edf9d53c67e6 100644 --- a/include/linux/thermal.h +++ b/include/linux/thermal.h @@ -165,6 +165,7 @@ struct thermal_attr { * @ops: operations this &thermal_zone_device supports * @tzp: thermal zone parameters * @governor: pointer to the governor for this thermal zone + * @governor_data: private pointer for governor data * @thermal_instances: list of &struct thermal_instance of this thermal zone * @idr: &struct idr to generate unique id for this zone's cooling * devices @@ -191,6 +192,7 @@ struct thermal_zone_device { struct thermal_zone_device_ops *ops; const struct thermal_zone_params *tzp; struct thermal_governor *governor; + void *governor_data; struct list_head thermal_instances; struct idr idr; struct mutex lock; @@ -201,12 +203,19 @@ struct thermal_zone_device { /** * struct thermal_governor - structure that holds thermal governor information * @name: name of the governor + * @bind_to_tz: callback called when binding to a thermal zone. If it + * returns 0, the governor is bound to the thermal zone, + * otherwise it fails. + * @unbind_from_tz: callback called when a governor is unbound from a + * thermal zone. * @throttle: callback called for every trip point even if temperature is * below the trip point temperature * @governor_list: node in thermal_governor_list (in thermal_core.c) */ struct thermal_governor { char name[THERMAL_NAME_LENGTH]; + int (*bind_to_tz)(struct thermal_zone_device *tz); + void (*unbind_from_tz)(struct thermal_zone_device *tz); int (*throttle)(struct thermal_zone_device *tz, int trip); struct list_head governor_list; }; -- 2.20.1