From 04fa9c804b0ed50a3c6bae1d4b60a2494c81a23f Mon Sep 17 00:00:00 2001 From: Matthias Kaehlcke Date: Wed, 18 Mar 2020 11:45:46 +0000 Subject: thermal: devfreq_cooling: Use PM QoS to set frequency limits Now that devfreq supports limiting the frequency range of a device through PM QoS make use of it instead of disabling OPPs that should not be used. The switch from disabling OPPs to PM QoS introduces a subtle behavioral change in case of conflicting requests (min > max): PM QoS gives precedence to the MIN_FREQUENCY request, while higher OPPs disabled with dev_pm_opp_disable() would override MIN_FREQUENCY. Signed-off-by: Matthias Kaehlcke Reviewed-by: Lukasz Luba Reviewed-by: Chanwoo Choi Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/20200318114548.19916-4-lukasz.luba@arm.com --- drivers/thermal/devfreq_cooling.c | 70 +++++++++++++-------------------------- 1 file changed, 23 insertions(+), 47 deletions(-) (limited to 'drivers/thermal') diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c index a87d4fa031c8..f7f32e98331b 100644 --- a/drivers/thermal/devfreq_cooling.c +++ b/drivers/thermal/devfreq_cooling.c @@ -24,11 +24,13 @@ #include #include #include +#include #include #include -#define SCALE_ERROR_MITIGATION 100 +#define HZ_PER_KHZ 1000 +#define SCALE_ERROR_MITIGATION 100 static DEFINE_IDA(devfreq_ida); @@ -54,6 +56,8 @@ static DEFINE_IDA(devfreq_ida); * The 'res_util' range is from 100 to (power_table[state] * 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. */ struct devfreq_cooling_device { int id; @@ -66,49 +70,9 @@ struct devfreq_cooling_device { struct devfreq_cooling_power *power_ops; u32 res_util; int capped_state; + struct dev_pm_qos_request req_max_freq; }; -/** - * 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) { @@ -135,7 +99,7 @@ static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev, struct devfreq_cooling_device *dfc = cdev->devdata; struct devfreq *df = dfc->devfreq; struct device *dev = df->dev.parent; - int ret; + unsigned long freq; if (state == dfc->cooling_state) return 0; @@ -145,9 +109,10 @@ static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev, if (state >= dfc->freq_table_size) return -EINVAL; - ret = partition_enable_opps(dfc, state); - if (ret) - return ret; + 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; @@ -530,9 +495,15 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df, if (err) goto free_dfc; - err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL); + err = dev_pm_qos_add_request(df->dev.parent, &dfc->req_max_freq, + DEV_PM_QOS_MAX_FREQUENCY, + PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE); if (err < 0) goto free_tables; + + err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL); + if (err < 0) + goto remove_qos_req; dfc->id = err; snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d", dfc->id); @@ -553,6 +524,10 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df, release_ida: ida_simple_remove(&devfreq_ida, dfc->id); + +remove_qos_req: + dev_pm_qos_remove_request(&dfc->req_max_freq); + free_tables: kfree(dfc->power_table); kfree(dfc->freq_table); @@ -601,6 +576,7 @@ void devfreq_cooling_unregister(struct thermal_cooling_device *cdev) thermal_cooling_device_unregister(dfc->cdev); ida_simple_remove(&devfreq_ida, dfc->id); + dev_pm_qos_remove_request(&dfc->req_max_freq); kfree(dfc->power_table); kfree(dfc->freq_table); -- cgit v1.2.3