diff options
Diffstat (limited to 'drivers/powercap/dtpm_devfreq.c')
| -rw-r--r-- | drivers/powercap/dtpm_devfreq.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/drivers/powercap/dtpm_devfreq.c b/drivers/powercap/dtpm_devfreq.c new file mode 100644 index 000000000..612c3b59d --- /dev/null +++ b/drivers/powercap/dtpm_devfreq.c @@ -0,0 +1,198 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2021 Linaro Limited + * + * Author: Daniel Lezcano <daniel.lezcano@linaro.org> + * + * The devfreq device combined with the energy model and the load can + * give an estimation of the power consumption as well as limiting the + * power. + * + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/cpumask.h> +#include <linux/devfreq.h> +#include <linux/dtpm.h> +#include <linux/energy_model.h> +#include <linux/of.h> +#include <linux/pm_qos.h> +#include <linux/slab.h> +#include <linux/units.h> + +struct dtpm_devfreq { + struct dtpm dtpm; + struct dev_pm_qos_request qos_req; + struct devfreq *devfreq; +}; + +static struct dtpm_devfreq *to_dtpm_devfreq(struct dtpm *dtpm) +{ + return container_of(dtpm, struct dtpm_devfreq, dtpm); +} + +static int update_pd_power_uw(struct dtpm *dtpm) +{ + struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm); + struct devfreq *devfreq = dtpm_devfreq->devfreq; + struct device *dev = devfreq->dev.parent; + struct em_perf_domain *pd = em_pd_get(dev); + + dtpm->power_min = pd->table[0].power; + + dtpm->power_max = pd->table[pd->nr_perf_states - 1].power; + + return 0; +} + +static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit) +{ + struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm); + struct devfreq *devfreq = dtpm_devfreq->devfreq; + struct device *dev = devfreq->dev.parent; + struct em_perf_domain *pd = em_pd_get(dev); + unsigned long freq; + int i; + + for (i = 0; i < pd->nr_perf_states; i++) { + if (pd->table[i].power > power_limit) + break; + } + + freq = pd->table[i - 1].frequency; + + dev_pm_qos_update_request(&dtpm_devfreq->qos_req, freq); + + power_limit = pd->table[i - 1].power; + + return power_limit; +} + +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 u64 get_pd_power_uw(struct dtpm *dtpm) +{ + struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm); + struct devfreq *devfreq = dtpm_devfreq->devfreq; + struct device *dev = devfreq->dev.parent; + struct em_perf_domain *pd = em_pd_get(dev); + struct devfreq_dev_status status; + unsigned long freq; + u64 power; + int i; + + mutex_lock(&devfreq->lock); + status = devfreq->last_status; + mutex_unlock(&devfreq->lock); + + freq = DIV_ROUND_UP(status.current_frequency, HZ_PER_KHZ); + _normalize_load(&status); + + for (i = 0; i < pd->nr_perf_states; i++) { + + if (pd->table[i].frequency < freq) + continue; + + power = pd->table[i].power; + power *= status.busy_time; + power >>= 10; + + return power; + } + + return 0; +} + +static void pd_release(struct dtpm *dtpm) +{ + struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm); + + if (dev_pm_qos_request_active(&dtpm_devfreq->qos_req)) + dev_pm_qos_remove_request(&dtpm_devfreq->qos_req); + + kfree(dtpm_devfreq); +} + +static struct dtpm_ops dtpm_ops = { + .set_power_uw = set_pd_power_limit, + .get_power_uw = get_pd_power_uw, + .update_power_uw = update_pd_power_uw, + .release = pd_release, +}; + +static int __dtpm_devfreq_setup(struct devfreq *devfreq, struct dtpm *parent) +{ + struct device *dev = devfreq->dev.parent; + struct dtpm_devfreq *dtpm_devfreq; + struct em_perf_domain *pd; + int ret = -ENOMEM; + + pd = em_pd_get(dev); + if (!pd) { + ret = dev_pm_opp_of_register_em(dev, NULL); + if (ret) { + pr_err("No energy model available for '%s'\n", dev_name(dev)); + return -EINVAL; + } + } + + dtpm_devfreq = kzalloc(sizeof(*dtpm_devfreq), GFP_KERNEL); + if (!dtpm_devfreq) + return -ENOMEM; + + dtpm_init(&dtpm_devfreq->dtpm, &dtpm_ops); + + dtpm_devfreq->devfreq = devfreq; + + ret = dtpm_register(dev_name(dev), &dtpm_devfreq->dtpm, parent); + if (ret) { + pr_err("Failed to register '%s': %d\n", dev_name(dev), ret); + kfree(dtpm_devfreq); + return ret; + } + + ret = dev_pm_qos_add_request(dev, &dtpm_devfreq->qos_req, + DEV_PM_QOS_MAX_FREQUENCY, + PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE); + if (ret) { + pr_err("Failed to add QoS request: %d\n", ret); + goto out_dtpm_unregister; + } + + dtpm_update_power(&dtpm_devfreq->dtpm); + + return 0; + +out_dtpm_unregister: + dtpm_unregister(&dtpm_devfreq->dtpm); + + return ret; +} + +static int dtpm_devfreq_setup(struct dtpm *dtpm, struct device_node *np) +{ + struct devfreq *devfreq; + + devfreq = devfreq_get_devfreq_by_node(np); + if (IS_ERR(devfreq)) + return 0; + + return __dtpm_devfreq_setup(devfreq, dtpm); +} + +struct dtpm_subsys_ops dtpm_devfreq_ops = { + .name = KBUILD_MODNAME, + .setup = dtpm_devfreq_setup, +}; |