diff options
Diffstat (limited to 'drivers/powercap/dtpm_cpu.c')
| -rw-r--r-- | drivers/powercap/dtpm_cpu.c | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c new file mode 100644 index 000000000000..6933c783c6b4 --- /dev/null +++ b/drivers/powercap/dtpm_cpu.c @@ -0,0 +1,257 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2020 Linaro Limited + * + * Author: Daniel Lezcano <daniel.lezcano@linaro.org> + * + * The DTPM CPU is based on the energy model. It hooks the CPU in the + * DTPM tree which in turns update the power number by propagating the + * power number from the CPU energy model information to the parents. + * + * The association between the power and the performance state, allows + * to set the power of the CPU at the OPP granularity. + * + * The CPU hotplug is supported and the power numbers will be updated + * if a CPU is hot plugged / unplugged. + */ +#include <linux/cpumask.h> +#include <linux/cpufreq.h> +#include <linux/cpuhotplug.h> +#include <linux/dtpm.h> +#include <linux/energy_model.h> +#include <linux/pm_qos.h> +#include <linux/slab.h> +#include <linux/units.h> + +static struct dtpm *__parent; + +static DEFINE_PER_CPU(struct dtpm *, dtpm_per_cpu); + +struct dtpm_cpu { + struct freq_qos_request qos_req; + int cpu; +}; + +/* + * When a new CPU is inserted at hotplug or boot time, add the power + * contribution and update the dtpm tree. + */ +static int power_add(struct dtpm *dtpm, struct em_perf_domain *em) +{ + u64 power_min, power_max; + + power_min = em->table[0].power; + power_min *= MICROWATT_PER_MILLIWATT; + power_min += dtpm->power_min; + + power_max = em->table[em->nr_perf_states - 1].power; + power_max *= MICROWATT_PER_MILLIWATT; + power_max += dtpm->power_max; + + return dtpm_update_power(dtpm, power_min, power_max); +} + +/* + * When a CPU is unplugged, remove its power contribution from the + * dtpm tree. + */ +static int power_sub(struct dtpm *dtpm, struct em_perf_domain *em) +{ + u64 power_min, power_max; + + power_min = em->table[0].power; + power_min *= MICROWATT_PER_MILLIWATT; + power_min = dtpm->power_min - power_min; + + power_max = em->table[em->nr_perf_states - 1].power; + power_max *= MICROWATT_PER_MILLIWATT; + power_max = dtpm->power_max - power_max; + + return dtpm_update_power(dtpm, power_min, power_max); +} + +static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit) +{ + struct dtpm_cpu *dtpm_cpu = dtpm->private; + struct em_perf_domain *pd; + struct cpumask cpus; + unsigned long freq; + u64 power; + int i, nr_cpus; + + pd = em_cpu_get(dtpm_cpu->cpu); + + cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus)); + + nr_cpus = cpumask_weight(&cpus); + + for (i = 0; i < pd->nr_perf_states; i++) { + + power = pd->table[i].power * MICROWATT_PER_MILLIWATT * nr_cpus; + + if (power > power_limit) + break; + } + + freq = pd->table[i - 1].frequency; + + freq_qos_update_request(&dtpm_cpu->qos_req, freq); + + power_limit = pd->table[i - 1].power * + MICROWATT_PER_MILLIWATT * nr_cpus; + + return power_limit; +} + +static u64 get_pd_power_uw(struct dtpm *dtpm) +{ + struct dtpm_cpu *dtpm_cpu = dtpm->private; + struct em_perf_domain *pd; + struct cpumask cpus; + unsigned long freq; + int i, nr_cpus; + + pd = em_cpu_get(dtpm_cpu->cpu); + freq = cpufreq_quick_get(dtpm_cpu->cpu); + cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus)); + nr_cpus = cpumask_weight(&cpus); + + for (i = 0; i < pd->nr_perf_states; i++) { + + if (pd->table[i].frequency < freq) + continue; + + return pd->table[i].power * + MICROWATT_PER_MILLIWATT * nr_cpus; + } + + return 0; +} + +static void pd_release(struct dtpm *dtpm) +{ + struct dtpm_cpu *dtpm_cpu = dtpm->private; + + if (freq_qos_request_active(&dtpm_cpu->qos_req)) + freq_qos_remove_request(&dtpm_cpu->qos_req); + + kfree(dtpm_cpu); +} + +static struct dtpm_ops dtpm_ops = { + .set_power_uw = set_pd_power_limit, + .get_power_uw = get_pd_power_uw, + .release = pd_release, +}; + +static int cpuhp_dtpm_cpu_offline(unsigned int cpu) +{ + struct cpufreq_policy *policy; + struct em_perf_domain *pd; + struct dtpm *dtpm; + + policy = cpufreq_cpu_get(cpu); + + if (!policy) + return 0; + + pd = em_cpu_get(cpu); + if (!pd) + return -EINVAL; + + dtpm = per_cpu(dtpm_per_cpu, cpu); + + power_sub(dtpm, pd); + + if (cpumask_weight(policy->cpus) != 1) + return 0; + + for_each_cpu(cpu, policy->related_cpus) + per_cpu(dtpm_per_cpu, cpu) = NULL; + + dtpm_unregister(dtpm); + + return 0; +} + +static int cpuhp_dtpm_cpu_online(unsigned int cpu) +{ + struct dtpm *dtpm; + struct dtpm_cpu *dtpm_cpu; + struct cpufreq_policy *policy; + struct em_perf_domain *pd; + char name[CPUFREQ_NAME_LEN]; + int ret = -ENOMEM; + + policy = cpufreq_cpu_get(cpu); + + if (!policy) + return 0; + + pd = em_cpu_get(cpu); + if (!pd) + return -EINVAL; + + dtpm = per_cpu(dtpm_per_cpu, cpu); + if (dtpm) + return power_add(dtpm, pd); + + dtpm = dtpm_alloc(&dtpm_ops); + if (!dtpm) + return -EINVAL; + + dtpm_cpu = kzalloc(sizeof(dtpm_cpu), GFP_KERNEL); + if (!dtpm_cpu) + goto out_kfree_dtpm; + + dtpm->private = dtpm_cpu; + dtpm_cpu->cpu = cpu; + + for_each_cpu(cpu, policy->related_cpus) + per_cpu(dtpm_per_cpu, cpu) = dtpm; + + sprintf(name, "cpu%d", dtpm_cpu->cpu); + + ret = dtpm_register(name, dtpm, __parent); + if (ret) + goto out_kfree_dtpm_cpu; + + ret = power_add(dtpm, pd); + if (ret) + goto out_dtpm_unregister; + + ret = freq_qos_add_request(&policy->constraints, + &dtpm_cpu->qos_req, FREQ_QOS_MAX, + pd->table[pd->nr_perf_states - 1].frequency); + if (ret) + goto out_power_sub; + + return 0; + +out_power_sub: + power_sub(dtpm, pd); + +out_dtpm_unregister: + dtpm_unregister(dtpm); + dtpm_cpu = NULL; + dtpm = NULL; + +out_kfree_dtpm_cpu: + for_each_cpu(cpu, policy->related_cpus) + per_cpu(dtpm_per_cpu, cpu) = NULL; + kfree(dtpm_cpu); + +out_kfree_dtpm: + kfree(dtpm); + return ret; +} + +int dtpm_register_cpu(struct dtpm *parent) +{ + __parent = parent; + + return cpuhp_setup_state(CPUHP_AP_DTPM_CPU_ONLINE, + "dtpm_cpu:online", + cpuhp_dtpm_cpu_online, + cpuhp_dtpm_cpu_offline); +} |