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Diffstat (limited to 'drivers/thermal/fair_share.c')
| -rw-r--r-- | drivers/thermal/fair_share.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/drivers/thermal/fair_share.c b/drivers/thermal/fair_share.c new file mode 100644 index 000000000000..792479f2b64b --- /dev/null +++ b/drivers/thermal/fair_share.c @@ -0,0 +1,133 @@ +/* + * fair_share.c - A simple weight based Thermal governor + * + * Copyright (C) 2012 Intel Corp + * Copyright (C) 2012 Durgadoss R <durgadoss.r@intel.com> + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * 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. + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/thermal.h> + +#include "thermal_core.h" + +/** + * get_trip_level: - obtains the current trip level for a zone + * @tz: thermal zone device + */ +static int get_trip_level(struct thermal_zone_device *tz) +{ + int count = 0; + unsigned long trip_temp; + + if (tz->trips == 0 || !tz->ops->get_trip_temp) + return 0; + + for (count = 0; count < tz->trips; count++) { + tz->ops->get_trip_temp(tz, count, &trip_temp); + if (tz->temperature < trip_temp) + break; + } + return count; +} + +static long get_target_state(struct thermal_zone_device *tz, + struct thermal_cooling_device *cdev, int weight, int level) +{ + unsigned long max_state; + + cdev->ops->get_max_state(cdev, &max_state); + + return (long)(weight * level * max_state) / (100 * tz->trips); +} + +/** + * fair_share_throttle - throttles devices asscciated with the given zone + * @tz - thermal_zone_device + * + * Throttling Logic: This uses three parameters to calculate the new + * throttle state of the cooling devices associated with the given zone. + * + * Parameters used for Throttling: + * P1. max_state: Maximum throttle state exposed by the cooling device. + * P2. weight[i]/100: + * How 'effective' the 'i'th device is, in cooling the given zone. + * P3. cur_trip_level/max_no_of_trips: + * This describes the extent to which the devices should be throttled. + * We do not want to throttle too much when we trip a lower temperature, + * whereas the throttling is at full swing if we trip critical levels. + * (Heavily assumes the trip points are in ascending order) + * new_state of cooling device = P3 * P2 * P1 + */ +static int fair_share_throttle(struct thermal_zone_device *tz, int trip) +{ + const struct thermal_zone_params *tzp; + struct thermal_cooling_device *cdev; + struct thermal_instance *instance; + int i; + int cur_trip_level = get_trip_level(tz); + + if (!tz->tzp || !tz->tzp->tbp) + return -EINVAL; + + tzp = tz->tzp; + + for (i = 0; i < tzp->num_tbps; i++) { + if (!tzp->tbp[i].cdev) + continue; + + cdev = tzp->tbp[i].cdev; + instance = get_thermal_instance(tz, cdev, trip); + if (!instance) + continue; + + instance->target = get_target_state(tz, cdev, + tzp->tbp[i].weight, cur_trip_level); + + instance->cdev->updated = false; + thermal_cdev_update(cdev); + } + return 0; +} + +static struct thermal_governor thermal_gov_fair_share = { + .name = "fair_share", + .throttle = fair_share_throttle, + .owner = THIS_MODULE, +}; + +static int __init thermal_gov_fair_share_init(void) +{ + return thermal_register_governor(&thermal_gov_fair_share); +} + +static void __exit thermal_gov_fair_share_exit(void) +{ + thermal_unregister_governor(&thermal_gov_fair_share); +} + +/* This should load after thermal framework */ +fs_initcall(thermal_gov_fair_share_init); +module_exit(thermal_gov_fair_share_exit); + +MODULE_AUTHOR("Durgadoss R"); +MODULE_DESCRIPTION("A simple weight based thermal throttling governor"); +MODULE_LICENSE("GPL"); |