--- /dev/null
+/*
+ * 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/slab.h>
+#include <linux/pm_opp.h>
+#include <linux/thermal.h>
+
+static DEFINE_MUTEX(devfreq_lock);
+static DEFINE_IDR(devfreq_idr);
+
+/**
+ * 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.
+ */
+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;
+};
+
+/**
+ * get_idr - function to get a unique id.
+ * @idr: struct idr * handle used to create a id.
+ * @id: int * value generated by this function.
+ *
+ * This function will populate @id with an unique
+ * id, using the idr API.
+ *
+ * Return: 0 on success, an error code on failure.
+ */
+static int get_idr(struct idr *idr, int *id)
+{
+ int ret;
+
+ mutex_lock(&devfreq_lock);
+ ret = idr_alloc(idr, NULL, 0, 0, GFP_KERNEL);
+ mutex_unlock(&devfreq_lock);
+ if (unlikely(ret < 0))
+ return ret;
+ *id = ret;
+
+ return 0;
+}
+
+/**
+ * release_idr - function to free the unique id.
+ * @idr: struct idr * handle used for creating the id.
+ * @id: int value representing the unique id.
+ */
+static void release_idr(struct idr *idr, int id)
+{
+ mutex_lock(&devfreq_lock);
+ idr_remove(idr, id);
+ mutex_unlock(&devfreq_lock);
+}
+
+/**
+ * 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;
+
+ rcu_read_lock();
+ opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);
+ rcu_read_unlock();
+
+ if (PTR_ERR(opp) == -ERANGE)
+ continue;
+ else if (IS_ERR(opp))
+ return PTR_ERR(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;
+}
+
+/**
+ * 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;
+ struct device *dev = df->dev.parent;
+ unsigned long voltage;
+ struct dev_pm_opp *opp;
+
+ if (!dfc->power_ops->get_static_power)
+ return 0;
+
+ rcu_read_lock();
+
+ opp = dev_pm_opp_find_freq_exact(dev, freq, true);
+ if (IS_ERR(opp) && (PTR_ERR(opp) == -ERANGE))
+ opp = dev_pm_opp_find_freq_exact(dev, freq, false);
+
+ voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
+
+ rcu_read_unlock();
+
+ if (voltage == 0) {
+ dev_warn_ratelimited(dev,
+ "Failed to get voltage for frequency %lu: %ld\n",
+ freq, IS_ERR(opp) ? PTR_ERR(opp) : 0);
+ return 0;
+ }
+
+ return dfc->power_ops->get_static_power(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)
+{
+ unsigned long 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(freq, voltage);
+
+ freq_mhz = freq / 1000000;
+ power = (u64)dfc_power->dyn_power_coeff * freq_mhz * voltage * voltage;
+ do_div(power, 1000000000);
+
+ return power;
+}
+
+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;
+ u32 dyn_power, static_power;
+
+ /* Get dynamic power for state */
+ state = freq_get_state(dfc, freq);
+ if (state == THERMAL_CSTATE_INVALID)
+ return -EAGAIN;
+
+ dyn_power = dfc->power_table[state];
+
+ /* Scale dynamic power for utilization */
+ dyn_power = (dyn_power * status->busy_time) / status->total_time;
+
+ /* Get static power */
+ static_power = get_static_power(dfc, freq);
+
+ *power = dyn_power + static_power;
+
+ return 0;
+}
+
+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 < 0 || 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;
+ int i;
+
+ 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;
+ dyn_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 (dyn_power >= dfc->power_table[i])
+ break;
+
+ *state = i;
+ 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)
+ ret = -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_dyn, voltage;
+ struct dev_pm_opp *opp;
+
+ rcu_read_lock();
+
+ opp = dev_pm_opp_find_freq_floor(dev, &freq);
+ if (IS_ERR(opp)) {
+ rcu_read_unlock();
+ ret = PTR_ERR(opp);
+ goto free_tables;
+ }
+
+ voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
+
+ rcu_read_unlock();
+
+ if (dfc->power_ops) {
+ power_dyn = get_dynamic_power(dfc, freq, voltage);
+
+ dev_dbg(dev, "Dynamic power table: %lu MHz @ %lu mV: %lu = %lu mW\n",
+ freq / 1000000, voltage, power_dyn, power_dyn);
+
+ power_table[i] = power_dyn;
+ }
+
+ 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 devfreq_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 = get_idr(&devfreq_idr, &dfc->id);
+ if (err)
+ goto free_tables;
+
+ 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_idr;
+ }
+
+ dfc->cdev = cdev;
+
+ return dfc;
+
+release_idr:
+ release_idr(&devfreq_idr, 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 devfreq_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 devfreq_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 devfreq_cooling_device *dfc)
+{
+ if (!dfc)
+ return;
+
+ thermal_cooling_device_unregister(dfc->cdev);
+ release_idr(&devfreq_idr, dfc->id);
+ kfree(dfc->power_table);
+ kfree(dfc->freq_table);
+
+ kfree(dfc);
+}
+EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);
projects / platform / kernel / linux-rpi.git / commitdiff