summaryrefslogtreecommitdiffstats
path: root/drivers/thermal/devfreq_cooling.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/thermal/devfreq_cooling.c')
-rw-r--r--drivers/thermal/devfreq_cooling.c544
1 files changed, 544 insertions, 0 deletions
diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c
new file mode 100644
index 000000000..24b474925
--- /dev/null
+++ b/drivers/thermal/devfreq_cooling.c
@@ -0,0 +1,544 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * devfreq_cooling: Thermal cooling device implementation for devices using
+ * devfreq
+ *
+ * Copyright (C) 2014-2015 ARM Limited
+ *
+ * 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/energy_model.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/pm_opp.h>
+#include <linux/pm_qos.h>
+#include <linux/thermal.h>
+#include <linux/units.h>
+
+#include <trace/events/thermal.h>
+
+#define SCALE_ERROR_MITIGATION 100
+
+/**
+ * struct devfreq_cooling_device - Devfreq cooling device
+ * devfreq_cooling_device registered.
+ * @cdev: Pointer to associated thermal cooling device.
+ * @cooling_ops: devfreq callbacks to thermal cooling device ops
+ * @devfreq: Pointer to associated devfreq device.
+ * @cooling_state: Current cooling state.
+ * @freq_table: Pointer to a table with the frequencies sorted in descending
+ * order. You can index the table by cooling device state
+ * @max_state: It is the last index, that is, one less than the number of the
+ * OPPs
+ * @power_ops: Pointer to devfreq_cooling_power, a more precised model.
+ * @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 * 100 for the
+ * corresponding 'state'.
+ * @capped_state: index to cooling state with in dynamic power budget
+ * @req_max_freq: PM QoS request for limiting the maximum frequency
+ * of the devfreq device.
+ * @em_pd: Energy Model for the associated Devfreq device
+ */
+struct devfreq_cooling_device {
+ struct thermal_cooling_device *cdev;
+ struct thermal_cooling_device_ops cooling_ops;
+ struct devfreq *devfreq;
+ unsigned long cooling_state;
+ u32 *freq_table;
+ size_t max_state;
+ struct devfreq_cooling_power *power_ops;
+ u32 res_util;
+ int capped_state;
+ struct dev_pm_qos_request req_max_freq;
+ struct em_perf_domain *em_pd;
+};
+
+static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ struct devfreq_cooling_device *dfc = cdev->devdata;
+
+ *state = dfc->max_state;
+
+ 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;
+ unsigned long freq;
+ int perf_idx;
+
+ if (state == dfc->cooling_state)
+ return 0;
+
+ dev_dbg(dev, "Setting cooling state %lu\n", state);
+
+ if (state > dfc->max_state)
+ return -EINVAL;
+
+ if (dfc->em_pd) {
+ perf_idx = dfc->max_state - state;
+ freq = dfc->em_pd->table[perf_idx].frequency * 1000;
+ } else {
+ freq = dfc->freq_table[state];
+ }
+
+ dev_pm_qos_update_request(&dfc->req_max_freq,
+ DIV_ROUND_UP(freq, HZ_PER_KHZ));
+
+ dfc->cooling_state = state;
+
+ return 0;
+}
+
+/**
+ * get_perf_idx() - get the performance index corresponding to a frequency
+ * @em_pd: Pointer to device's Energy Model
+ * @freq: frequency in kHz
+ *
+ * Return: the performance index associated with the @freq, or
+ * -EINVAL if it wasn't found.
+ */
+static int get_perf_idx(struct em_perf_domain *em_pd, unsigned long freq)
+{
+ int i;
+
+ for (i = 0; i < em_pd->nr_perf_states; i++) {
+ if (em_pd->table[i].frequency == freq)
+ return i;
+ }
+
+ return -EINVAL;
+}
+
+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;
+}
+
+static void _normalize_load(struct devfreq_dev_status *status)
+{
+ if (status->total_time > 0xfffff) {
+ status->total_time >>= 10;
+ status->busy_time >>= 10;
+ }
+
+ status->busy_time <<= 10;
+ status->busy_time /= status->total_time ? : 1;
+
+ status->busy_time = status->busy_time ? : 1;
+ status->total_time = 1024;
+}
+
+static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev,
+ u32 *power)
+{
+ struct devfreq_cooling_device *dfc = cdev->devdata;
+ struct devfreq *df = dfc->devfreq;
+ struct devfreq_dev_status status;
+ unsigned long state;
+ unsigned long freq;
+ unsigned long voltage;
+ int res, perf_idx;
+
+ mutex_lock(&df->lock);
+ status = df->last_status;
+ mutex_unlock(&df->lock);
+
+ freq = status.current_frequency;
+
+ if (dfc->power_ops && 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;
+
+ /* Convert EM power into milli-Watts first */
+ dfc->res_util = dfc->em_pd->table[state].power;
+ dfc->res_util /= MICROWATT_PER_MILLIWATT;
+
+ dfc->res_util *= SCALE_ERROR_MITIGATION;
+
+ if (*power > 1)
+ dfc->res_util /= *power;
+ } else {
+ goto fail;
+ }
+ } else {
+ /* Energy Model frequencies are in kHz */
+ perf_idx = get_perf_idx(dfc->em_pd, freq / 1000);
+ if (perf_idx < 0) {
+ res = -EAGAIN;
+ goto fail;
+ }
+
+ _normalize_load(&status);
+
+ /* Convert EM power into milli-Watts first */
+ *power = dfc->em_pd->table[perf_idx].power;
+ *power /= MICROWATT_PER_MILLIWATT;
+ /* Scale power for utilization */
+ *power *= status.busy_time;
+ *power >>= 10;
+ }
+
+ trace_thermal_power_devfreq_get_power(cdev, &status, freq, *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,
+ unsigned long state, u32 *power)
+{
+ struct devfreq_cooling_device *dfc = cdev->devdata;
+ int perf_idx;
+
+ if (state > dfc->max_state)
+ return -EINVAL;
+
+ perf_idx = dfc->max_state - state;
+ *power = dfc->em_pd->table[perf_idx].power;
+ *power /= MICROWATT_PER_MILLIWATT;
+
+ return 0;
+}
+
+static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,
+ u32 power, unsigned long *state)
+{
+ struct devfreq_cooling_device *dfc = cdev->devdata;
+ struct devfreq *df = dfc->devfreq;
+ struct devfreq_dev_status status;
+ unsigned long freq, em_power_mw;
+ s32 est_power;
+ int i;
+
+ mutex_lock(&df->lock);
+ status = df->last_status;
+ mutex_unlock(&df->lock);
+
+ freq = status.current_frequency;
+
+ if (dfc->power_ops && dfc->power_ops->get_real_power) {
+ /* Scale for resource utilization */
+ est_power = power * dfc->res_util;
+ est_power /= SCALE_ERROR_MITIGATION;
+ } else {
+ /* Scale dynamic power for utilization */
+ _normalize_load(&status);
+ est_power = power << 10;
+ est_power /= status.busy_time;
+ }
+
+ /*
+ * Find the first cooling state that is within the power
+ * budget. The EM power table is sorted ascending.
+ */
+ for (i = dfc->max_state; i > 0; i--) {
+ /* Convert EM power to milli-Watts to make safe comparison */
+ em_power_mw = dfc->em_pd->table[i].power;
+ em_power_mw /= MICROWATT_PER_MILLIWATT;
+ if (est_power >= em_power_mw)
+ break;
+ }
+
+ *state = dfc->max_state - i;
+ dfc->capped_state = *state;
+
+ trace_thermal_power_devfreq_limit(cdev, freq, *state, power);
+ return 0;
+}
+
+/**
+ * devfreq_cooling_gen_tables() - Generate frequency table.
+ * @dfc: Pointer to devfreq cooling device.
+ * @num_opps: Number of OPPs
+ *
+ * Generate frequency table which holds the frequencies in descending
+ * order. That way its indexed by cooling device state. This is for
+ * compatibility with drivers which do not register Energy Model.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc,
+ int num_opps)
+{
+ struct devfreq *df = dfc->devfreq;
+ struct device *dev = df->dev.parent;
+ unsigned long freq;
+ int i;
+
+ dfc->freq_table = kcalloc(num_opps, sizeof(*dfc->freq_table),
+ GFP_KERNEL);
+ if (!dfc->freq_table)
+ return -ENOMEM;
+
+ for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) {
+ struct dev_pm_opp *opp;
+
+ opp = dev_pm_opp_find_freq_floor(dev, &freq);
+ if (IS_ERR(opp)) {
+ kfree(dfc->freq_table);
+ return PTR_ERR(opp);
+ }
+
+ dev_pm_opp_put(opp);
+ dfc->freq_table[i] = freq;
+ }
+
+ return 0;
+}
+
+/**
+ * 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 device *dev = df->dev.parent;
+ struct devfreq_cooling_device *dfc;
+ struct em_perf_domain *em;
+ struct thermal_cooling_device_ops *ops;
+ char *name;
+ int err, num_opps;
+
+
+ dfc = kzalloc(sizeof(*dfc), GFP_KERNEL);
+ if (!dfc)
+ return ERR_PTR(-ENOMEM);
+
+ dfc->devfreq = df;
+
+ ops = &dfc->cooling_ops;
+ ops->get_max_state = devfreq_cooling_get_max_state;
+ ops->get_cur_state = devfreq_cooling_get_cur_state;
+ ops->set_cur_state = devfreq_cooling_set_cur_state;
+
+ em = em_pd_get(dev);
+ if (em && !em_is_artificial(em)) {
+ dfc->em_pd = em;
+ ops->get_requested_power =
+ devfreq_cooling_get_requested_power;
+ ops->state2power = devfreq_cooling_state2power;
+ ops->power2state = devfreq_cooling_power2state;
+
+ dfc->power_ops = dfc_power;
+
+ num_opps = em_pd_nr_perf_states(dfc->em_pd);
+ } else {
+ /* Backward compatibility for drivers which do not use IPA */
+ dev_dbg(dev, "missing proper EM for cooling device\n");
+
+ num_opps = dev_pm_opp_get_opp_count(dev);
+
+ err = devfreq_cooling_gen_tables(dfc, num_opps);
+ if (err)
+ goto free_dfc;
+ }
+
+ if (num_opps <= 0) {
+ err = -EINVAL;
+ goto free_dfc;
+ }
+
+ /* max_state is an index, not a counter */
+ dfc->max_state = num_opps - 1;
+
+ err = dev_pm_qos_add_request(dev, &dfc->req_max_freq,
+ DEV_PM_QOS_MAX_FREQUENCY,
+ PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
+ if (err < 0)
+ goto free_table;
+
+ err = -ENOMEM;
+ name = kasprintf(GFP_KERNEL, "devfreq-%s", dev_name(dev));
+ if (!name)
+ goto remove_qos_req;
+
+ cdev = thermal_of_cooling_device_register(np, name, dfc, ops);
+ kfree(name);
+
+ if (IS_ERR(cdev)) {
+ err = PTR_ERR(cdev);
+ dev_err(dev,
+ "Failed to register devfreq cooling device (%d)\n",
+ err);
+ goto remove_qos_req;
+ }
+
+ dfc->cdev = cdev;
+
+ return cdev;
+
+remove_qos_req:
+ dev_pm_qos_remove_request(&dfc->req_max_freq);
+free_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_em_register() - Register devfreq cooling device with
+ * power information and automatically register Energy Model (EM)
+ * @df: Pointer to devfreq device.
+ * @dfc_power: Pointer to devfreq_cooling_power.
+ *
+ * Register a devfreq cooling device and automatically register EM. The
+ * available OPPs must be registered for the device.
+ *
+ * If @dfc_power is provided, the cooling device is registered with the
+ * power extensions. It is using the simple Energy Model which requires
+ * "dynamic-power-coefficient" a devicetree property. To not break drivers
+ * which miss that DT property, the function won't bail out when the EM
+ * registration failed. The cooling device will be registered if everything
+ * else is OK.
+ */
+struct thermal_cooling_device *
+devfreq_cooling_em_register(struct devfreq *df,
+ struct devfreq_cooling_power *dfc_power)
+{
+ struct thermal_cooling_device *cdev;
+ struct device *dev;
+ int ret;
+
+ if (IS_ERR_OR_NULL(df))
+ return ERR_PTR(-EINVAL);
+
+ dev = df->dev.parent;
+
+ ret = dev_pm_opp_of_register_em(dev, NULL);
+ if (ret)
+ dev_dbg(dev, "Unable to register EM for devfreq cooling device (%d)\n",
+ ret);
+
+ cdev = of_devfreq_cooling_register_power(dev->of_node, df, dfc_power);
+
+ if (IS_ERR_OR_NULL(cdev))
+ em_dev_unregister_perf_domain(dev);
+
+ return cdev;
+}
+EXPORT_SYMBOL_GPL(devfreq_cooling_em_register);
+
+/**
+ * devfreq_cooling_unregister() - Unregister devfreq cooling device.
+ * @cdev: Pointer to devfreq cooling device to unregister.
+ *
+ * Unregisters devfreq cooling device and related Energy Model if it was
+ * present.
+ */
+void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
+{
+ struct devfreq_cooling_device *dfc;
+ struct device *dev;
+
+ if (IS_ERR_OR_NULL(cdev))
+ return;
+
+ dfc = cdev->devdata;
+ dev = dfc->devfreq->dev.parent;
+
+ thermal_cooling_device_unregister(dfc->cdev);
+ dev_pm_qos_remove_request(&dfc->req_max_freq);
+
+ em_dev_unregister_perf_domain(dev);
+
+ kfree(dfc->freq_table);
+ kfree(dfc);
+}
+EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);