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Diffstat (limited to '')
| -rw-r--r-- | drivers/thermal/devfreq_cooling.c | 608 |
1 files changed, 608 insertions, 0 deletions
diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c new file mode 100644 index 000000000..ef5925688 --- /dev/null +++ b/drivers/thermal/devfreq_cooling.c @@ -0,0 +1,608 @@ +/* + * 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 <linux/devfreq.h> +#include <linux/devfreq_cooling.h> +#include <linux/export.h> +#include <linux/idr.h> +#include <linux/slab.h> +#include <linux/pm_opp.h> +#include <linux/thermal.h> + +#include <trace/events/thermal.h> + +#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); |