drivers/powercap/dtpm_devfreq.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright 2021 Linaro Limited
   4  *
   5  * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
   6  *
   7  * The devfreq device combined with the energy model and the load can
   8  * give an estimation of the power consumption as well as limiting the
   9  * power.
  10  *
  11  */
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/cpumask.h>
  15 #include <linux/devfreq.h>
  16 #include <linux/dtpm.h>
  17 #include <linux/energy_model.h>
  18 #include <linux/of.h>
  19 #include <linux/pm_qos.h>
  20 #include <linux/slab.h>
  21 #include <linux/units.h>
  22
  23 struct dtpm_devfreq {
  24         struct dtpm dtpm;
  25         struct dev_pm_qos_request qos_req;
  26         struct devfreq *devfreq;
  27 };
  28
  29 static struct dtpm_devfreq *to_dtpm_devfreq(struct dtpm *dtpm)
  30 {
  31         return container_of(dtpm, struct dtpm_devfreq, dtpm);
  32 }
  33
  34 static int update_pd_power_uw(struct dtpm *dtpm)
  35 {
  36         struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm);
  37         struct devfreq *devfreq = dtpm_devfreq->devfreq;
  38         struct device *dev = devfreq->dev.parent;
  39         struct em_perf_domain *pd = em_pd_get(dev);
  40
  41         dtpm->power_min = pd->table[0].power;
  42
  43         dtpm->power_max = pd->table[pd->nr_perf_states - 1].power;
  44
  45         return 0;
  46 }
  47
  48 static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit)
  49 {
  50         struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm);
  51         struct devfreq *devfreq = dtpm_devfreq->devfreq;
  52         struct device *dev = devfreq->dev.parent;
  53         struct em_perf_domain *pd = em_pd_get(dev);
  54         unsigned long freq;
  55         int i;
  56
  57         for (i = 0; i < pd->nr_perf_states; i++) {
  58                 if (pd->table[i].power > power_limit)
  59                         break;
  60         }
  61
  62         freq = pd->table[i - 1].frequency;
  63
  64         dev_pm_qos_update_request(&dtpm_devfreq->qos_req, freq);
  65
  66         power_limit = pd->table[i - 1].power;
  67
  68         return power_limit;
  69 }
  70
  71 static void _normalize_load(struct devfreq_dev_status *status)
  72 {
  73         if (status->total_time > 0xfffff) {
  74                 status->total_time >>= 10;
  75                 status->busy_time >>= 10;
  76         }
  77
  78         status->busy_time <<= 10;
  79         status->busy_time /= status->total_time ? : 1;
  80
  81         status->busy_time = status->busy_time ? : 1;
  82         status->total_time = 1024;
  83 }
  84
  85 static u64 get_pd_power_uw(struct dtpm *dtpm)
  86 {
  87         struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm);
  88         struct devfreq *devfreq = dtpm_devfreq->devfreq;
  89         struct device *dev = devfreq->dev.parent;
  90         struct em_perf_domain *pd = em_pd_get(dev);
  91         struct devfreq_dev_status status;
  92         unsigned long freq;
  93         u64 power;
  94         int i;
  95
  96         mutex_lock(&devfreq->lock);
  97         status = devfreq->last_status;
  98         mutex_unlock(&devfreq->lock);
  99
 100         freq = DIV_ROUND_UP(status.current_frequency, HZ_PER_KHZ);
 101         _normalize_load(&status);
 102
 103         for (i = 0; i < pd->nr_perf_states; i++) {
 104
 105                 if (pd->table[i].frequency < freq)
 106                         continue;
 107
 108                 power = pd->table[i].power;
 109                 power *= status.busy_time;
 110                 power >>= 10;
 111
 112                 return power;
 113         }
 114
 115         return 0;
 116 }
 117
 118 static void pd_release(struct dtpm *dtpm)
 119 {
 120         struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm);
 121
 122         if (dev_pm_qos_request_active(&dtpm_devfreq->qos_req))
 123                 dev_pm_qos_remove_request(&dtpm_devfreq->qos_req);
 124
 125         kfree(dtpm_devfreq);
 126 }
 127
 128 static struct dtpm_ops dtpm_ops = {
 129         .set_power_uw = set_pd_power_limit,
 130         .get_power_uw = get_pd_power_uw,
 131         .update_power_uw = update_pd_power_uw,
 132         .release = pd_release,
 133 };
 134
 135 static int __dtpm_devfreq_setup(struct devfreq *devfreq, struct dtpm *parent)
 136 {
 137         struct device *dev = devfreq->dev.parent;
 138         struct dtpm_devfreq *dtpm_devfreq;
 139         struct em_perf_domain *pd;
 140         int ret = -ENOMEM;
 141
 142         pd = em_pd_get(dev);
 143         if (!pd) {
 144                 ret = dev_pm_opp_of_register_em(dev, NULL);
 145                 if (ret) {
 146                         pr_err("No energy model available for '%s'\n", dev_name(dev));
 147                         return -EINVAL;
 148                 }
 149         }
 150
 151         dtpm_devfreq = kzalloc(sizeof(*dtpm_devfreq), GFP_KERNEL);
 152         if (!dtpm_devfreq)
 153                 return -ENOMEM;
 154
 155         dtpm_init(&dtpm_devfreq->dtpm, &dtpm_ops);
 156
 157         dtpm_devfreq->devfreq = devfreq;
 158
 159         ret = dtpm_register(dev_name(dev), &dtpm_devfreq->dtpm, parent);
 160         if (ret) {
 161                 pr_err("Failed to register '%s': %d\n", dev_name(dev), ret);
 162                 kfree(dtpm_devfreq);
 163                 return ret;
 164         }
 165
 166         ret = dev_pm_qos_add_request(dev, &dtpm_devfreq->qos_req,
 167                                      DEV_PM_QOS_MAX_FREQUENCY,
 168                                      PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
 169         if (ret) {
 170                 pr_err("Failed to add QoS request: %d\n", ret);
 171                 goto out_dtpm_unregister;
 172         }
 173
 174         dtpm_update_power(&dtpm_devfreq->dtpm);
 175
 176         return 0;
 177
 178 out_dtpm_unregister:
 179         dtpm_unregister(&dtpm_devfreq->dtpm);
 180
 181         return ret;
 182 }
 183
 184 static int dtpm_devfreq_setup(struct dtpm *dtpm, struct device_node *np)
 185 {
 186         struct devfreq *devfreq;
 187
 188         devfreq = devfreq_get_devfreq_by_node(np);
 189         if (IS_ERR(devfreq))
 190                 return 0;
 191
 192         return __dtpm_devfreq_setup(devfreq, dtpm);
 193 }
 194
 195 struct dtpm_subsys_ops dtpm_devfreq_ops = {
 196         .name = KBUILD_MODNAME,
 197         .setup = dtpm_devfreq_setup,
 198 };