/* * devfreq_cooling: Thermal cooling device implementation for devices using * devfreq * * Copyright (C) 2014-2015 ARM Limited * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * This program is distributed "as is" WITHOUT ANY WARRANTY of any * kind, whether express or implied; without even the implied warranty * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * TODO: * - If OPPs are added or removed after devfreq cooling has * registered, the devfreq cooling won't react to it. */ #include #include #include #include #include #include #include #include #define SCALE_ERROR_MITIGATION 100 static DEFINE_IDA(devfreq_ida); /** * struct devfreq_cooling_device - Devfreq cooling device * @id: unique integer value corresponding to each * devfreq_cooling_device registered. * @cdev: Pointer to associated thermal cooling device. * @devfreq: Pointer to associated devfreq device. * @cooling_state: Current cooling state. * @power_table: Pointer to table with maximum power draw for each * cooling state. State is the index into the table, and * the power is in mW. * @freq_table: Pointer to a table with the frequencies sorted in descending * order. You can index the table by cooling device state * @freq_table_size: Size of the @freq_table and @power_table * @power_ops: Pointer to devfreq_cooling_power, used to generate the * @power_table. * @res_util: Resource utilization scaling factor for the power. * It is multiplied by 100 to minimize the error. It is used * for estimation of the power budget instead of using * 'utilization' (which is 'busy_time / 'total_time'). * The 'res_util' range is from 100 to (power_table[state] * 100) * for the corresponding 'state'. */ struct devfreq_cooling_device { int id; struct thermal_cooling_device *cdev; struct devfreq *devfreq; unsigned long cooling_state; u32 *power_table; u32 *freq_table; size_t freq_table_size; struct devfreq_cooling_power *power_ops; u32 res_util; int capped_state; }; /** * partition_enable_opps() - disable all opps above a given state * @dfc: Pointer to devfreq we are operating on * @cdev_state: cooling device state we're setting * * Go through the OPPs of the device, enabling all OPPs until * @cdev_state and disabling those frequencies above it. */ static int partition_enable_opps(struct devfreq_cooling_device *dfc, unsigned long cdev_state) { int i; struct device *dev = dfc->devfreq->dev.parent; for (i = 0; i < dfc->freq_table_size; i++) { struct dev_pm_opp *opp; int ret = 0; unsigned int freq = dfc->freq_table[i]; bool want_enable = i >= cdev_state ? true : false; opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable); if (PTR_ERR(opp) == -ERANGE) continue; else if (IS_ERR(opp)) return PTR_ERR(opp); dev_pm_opp_put(opp); if (want_enable) ret = dev_pm_opp_enable(dev, freq); else ret = dev_pm_opp_disable(dev, freq); if (ret) return ret; } return 0; } static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state) { struct devfreq_cooling_device *dfc = cdev->devdata; *state = dfc->freq_table_size - 1; return 0; } static int devfreq_cooling_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state) { struct devfreq_cooling_device *dfc = cdev->devdata; *state = dfc->cooling_state; return 0; } static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) { struct devfreq_cooling_device *dfc = cdev->devdata; struct devfreq *df = dfc->devfreq; struct device *dev = df->dev.parent; int ret; if (state == dfc->cooling_state) return 0; dev_dbg(dev, "Setting cooling state %lu\n", state); if (state >= dfc->freq_table_size) return -EINVAL; ret = partition_enable_opps(dfc, state); if (ret) return ret; dfc->cooling_state = state; return 0; } /** * freq_get_state() - get the cooling state corresponding to a frequency * @dfc: Pointer to devfreq cooling device * @freq: frequency in Hz * * Return: the cooling state associated with the @freq, or * THERMAL_CSTATE_INVALID if it wasn't found. */ static unsigned long freq_get_state(struct devfreq_cooling_device *dfc, unsigned long freq) { int i; for (i = 0; i < dfc->freq_table_size; i++) { if (dfc->freq_table[i] == freq) return i; } return THERMAL_CSTATE_INVALID; } static unsigned long get_voltage(struct devfreq *df, unsigned long freq) { struct device *dev = df->dev.parent; unsigned long voltage; struct dev_pm_opp *opp; opp = dev_pm_opp_find_freq_exact(dev, freq, true); if (PTR_ERR(opp) == -ERANGE) opp = dev_pm_opp_find_freq_exact(dev, freq, false); if (IS_ERR(opp)) { dev_err_ratelimited(dev, "Failed to find OPP for frequency %lu: %ld\n", freq, PTR_ERR(opp)); return 0; } voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */ dev_pm_opp_put(opp); if (voltage == 0) { dev_err_ratelimited(dev, "Failed to get voltage for frequency %lu\n", freq); } return voltage; } /** * get_static_power() - calculate the static power * @dfc: Pointer to devfreq cooling device * @freq: Frequency in Hz * * Calculate the static power in milliwatts using the supplied * get_static_power(). The current voltage is calculated using the * OPP library. If no get_static_power() was supplied, assume the * static power is negligible. */ static unsigned long get_static_power(struct devfreq_cooling_device *dfc, unsigned long freq) { struct devfreq *df = dfc->devfreq; unsigned long voltage; if (!dfc->power_ops->get_static_power) return 0; voltage = get_voltage(df, freq); if (voltage == 0) return 0; return dfc->power_ops->get_static_power(df, voltage); } /** * get_dynamic_power - calculate the dynamic power * @dfc: Pointer to devfreq cooling device * @freq: Frequency in Hz * @voltage: Voltage in millivolts * * Calculate the dynamic power in milliwatts consumed by the device at * frequency @freq and voltage @voltage. If the get_dynamic_power() * was supplied as part of the devfreq_cooling_power struct, then that * function is used. Otherwise, a simple power model (Pdyn = Coeff * * Voltage^2 * Frequency) is used. */ static unsigned long get_dynamic_power(struct devfreq_cooling_device *dfc, unsigned long freq, unsigned long voltage) { u64 power; u32 freq_mhz; struct devfreq_cooling_power *dfc_power = dfc->power_ops; if (dfc_power->get_dynamic_power) return dfc_power->get_dynamic_power(dfc->devfreq, freq, voltage); freq_mhz = freq / 1000000; power = (u64)dfc_power->dyn_power_coeff * freq_mhz * voltage * voltage; do_div(power, 1000000000); return power; } static inline unsigned long get_total_power(struct devfreq_cooling_device *dfc, unsigned long freq, unsigned long voltage) { return get_static_power(dfc, freq) + get_dynamic_power(dfc, freq, voltage); } static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev, struct thermal_zone_device *tz, u32 *power) { struct devfreq_cooling_device *dfc = cdev->devdata; struct devfreq *df = dfc->devfreq; struct devfreq_dev_status *status = &df->last_status; unsigned long state; unsigned long freq = status->current_frequency; unsigned long voltage; u32 dyn_power = 0; u32 static_power = 0; int res; state = freq_get_state(dfc, freq); if (state == THERMAL_CSTATE_INVALID) { res = -EAGAIN; goto fail; } if (dfc->power_ops->get_real_power) { voltage = get_voltage(df, freq); if (voltage == 0) { res = -EINVAL; goto fail; } res = dfc->power_ops->get_real_power(df, power, freq, voltage); if (!res) { state = dfc->capped_state; dfc->res_util = dfc->power_table[state]; dfc->res_util *= SCALE_ERROR_MITIGATION; if (*power > 1) dfc->res_util /= *power; } else { goto fail; } } else { dyn_power = dfc->power_table[state]; /* Scale dynamic power for utilization */ dyn_power *= status->busy_time; dyn_power /= status->total_time; /* Get static power */ static_power = get_static_power(dfc, freq); *power = dyn_power + static_power; } trace_thermal_power_devfreq_get_power(cdev, status, freq, dyn_power, static_power, *power); return 0; fail: /* It is safe to set max in this case */ dfc->res_util = SCALE_ERROR_MITIGATION; return res; } static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev, struct thermal_zone_device *tz, unsigned long state, u32 *power) { struct devfreq_cooling_device *dfc = cdev->devdata; unsigned long freq; u32 static_power; if (state >= dfc->freq_table_size) return -EINVAL; freq = dfc->freq_table[state]; static_power = get_static_power(dfc, freq); *power = dfc->power_table[state] + static_power; return 0; } static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev, struct thermal_zone_device *tz, u32 power, unsigned long *state) { struct devfreq_cooling_device *dfc = cdev->devdata; struct devfreq *df = dfc->devfreq; struct devfreq_dev_status *status = &df->last_status; unsigned long freq = status->current_frequency; unsigned long busy_time; s32 dyn_power; u32 static_power; s32 est_power; int i; if (dfc->power_ops->get_real_power) { /* Scale for resource utilization */ est_power = power * dfc->res_util; est_power /= SCALE_ERROR_MITIGATION; } else { static_power = get_static_power(dfc, freq); dyn_power = power - static_power; dyn_power = dyn_power > 0 ? dyn_power : 0; /* Scale dynamic power for utilization */ busy_time = status->busy_time ?: 1; est_power = (dyn_power * status->total_time) / busy_time; } /* * Find the first cooling state that is within the power * budget for dynamic power. */ for (i = 0; i < dfc->freq_table_size - 1; i++) if (est_power >= dfc->power_table[i]) break; *state = i; dfc->capped_state = i; trace_thermal_power_devfreq_limit(cdev, freq, *state, power); return 0; } static struct thermal_cooling_device_ops devfreq_cooling_ops = { .get_max_state = devfreq_cooling_get_max_state, .get_cur_state = devfreq_cooling_get_cur_state, .set_cur_state = devfreq_cooling_set_cur_state, }; /** * devfreq_cooling_gen_tables() - Generate power and freq tables. * @dfc: Pointer to devfreq cooling device. * * Generate power and frequency tables: the power table hold the * device's maximum power usage at each cooling state (OPP). The * static and dynamic power using the appropriate voltage and * frequency for the state, is acquired from the struct * devfreq_cooling_power, and summed to make the maximum power draw. * * The frequency table holds the frequencies in descending order. * That way its indexed by cooling device state. * * The tables are malloced, and pointers put in dfc. They must be * freed when unregistering the devfreq cooling device. * * Return: 0 on success, negative error code on failure. */ static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc) { struct devfreq *df = dfc->devfreq; struct device *dev = df->dev.parent; int ret, num_opps; unsigned long freq; u32 *power_table = NULL; u32 *freq_table; int i; num_opps = dev_pm_opp_get_opp_count(dev); if (dfc->power_ops) { power_table = kcalloc(num_opps, sizeof(*power_table), GFP_KERNEL); if (!power_table) return -ENOMEM; } freq_table = kcalloc(num_opps, sizeof(*freq_table), GFP_KERNEL); if (!freq_table) { ret = -ENOMEM; goto free_power_table; } for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) { unsigned long power, voltage; struct dev_pm_opp *opp; opp = dev_pm_opp_find_freq_floor(dev, &freq); if (IS_ERR(opp)) { ret = PTR_ERR(opp); goto free_tables; } voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */ dev_pm_opp_put(opp); if (dfc->power_ops) { if (dfc->power_ops->get_real_power) power = get_total_power(dfc, freq, voltage); else power = get_dynamic_power(dfc, freq, voltage); dev_dbg(dev, "Power table: %lu MHz @ %lu mV: %lu = %lu mW\n", freq / 1000000, voltage, power, power); power_table[i] = power; } freq_table[i] = freq; } if (dfc->power_ops) dfc->power_table = power_table; dfc->freq_table = freq_table; dfc->freq_table_size = num_opps; return 0; free_tables: kfree(freq_table); free_power_table: kfree(power_table); return ret; } /** * of_devfreq_cooling_register_power() - Register devfreq cooling device, * with OF and power information. * @np: Pointer to OF device_node. * @df: Pointer to devfreq device. * @dfc_power: Pointer to devfreq_cooling_power. * * Register a devfreq cooling device. The available OPPs must be * registered on the device. * * If @dfc_power is provided, the cooling device is registered with the * power extensions. For the power extensions to work correctly, * devfreq should use the simple_ondemand governor, other governors * are not currently supported. */ struct thermal_cooling_device * of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df, struct devfreq_cooling_power *dfc_power) { struct thermal_cooling_device *cdev; struct devfreq_cooling_device *dfc; char dev_name[THERMAL_NAME_LENGTH]; int err; dfc = kzalloc(sizeof(*dfc), GFP_KERNEL); if (!dfc) return ERR_PTR(-ENOMEM); dfc->devfreq = df; if (dfc_power) { dfc->power_ops = dfc_power; devfreq_cooling_ops.get_requested_power = devfreq_cooling_get_requested_power; devfreq_cooling_ops.state2power = devfreq_cooling_state2power; devfreq_cooling_ops.power2state = devfreq_cooling_power2state; } err = devfreq_cooling_gen_tables(dfc); if (err) goto free_dfc; err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL); if (err < 0) goto free_tables; dfc->id = err; snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d", dfc->id); cdev = thermal_of_cooling_device_register(np, dev_name, dfc, &devfreq_cooling_ops); if (IS_ERR(cdev)) { err = PTR_ERR(cdev); dev_err(df->dev.parent, "Failed to register devfreq cooling device (%d)\n", err); goto release_ida; } dfc->cdev = cdev; return cdev; release_ida: ida_simple_remove(&devfreq_ida, dfc->id); free_tables: kfree(dfc->power_table); kfree(dfc->freq_table); free_dfc: kfree(dfc); return ERR_PTR(err); } EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power); /** * of_devfreq_cooling_register() - Register devfreq cooling device, * with OF information. * @np: Pointer to OF device_node. * @df: Pointer to devfreq device. */ struct thermal_cooling_device * of_devfreq_cooling_register(struct device_node *np, struct devfreq *df) { return of_devfreq_cooling_register_power(np, df, NULL); } EXPORT_SYMBOL_GPL(of_devfreq_cooling_register); /** * devfreq_cooling_register() - Register devfreq cooling device. * @df: Pointer to devfreq device. */ struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df) { return of_devfreq_cooling_register(NULL, df); } EXPORT_SYMBOL_GPL(devfreq_cooling_register); /** * devfreq_cooling_unregister() - Unregister devfreq cooling device. * @dfc: Pointer to devfreq cooling device to unregister. */ void devfreq_cooling_unregister(struct thermal_cooling_device *cdev) { struct devfreq_cooling_device *dfc; if (!cdev) return; dfc = cdev->devdata; thermal_cooling_device_unregister(dfc->cdev); ida_simple_remove(&devfreq_ida, dfc->id); kfree(dfc->power_table); kfree(dfc->freq_table); kfree(dfc); } EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);