| // 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. |
| */ |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/cpumask.h> |
| #include <linux/cpufreq.h> |
| #include <linux/cpuhotplug.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_cpu { |
| struct dtpm dtpm; |
| struct freq_qos_request qos_req; |
| int cpu; |
| }; |
| |
| static DEFINE_PER_CPU(struct dtpm_cpu *, dtpm_per_cpu); |
| |
| static struct dtpm_cpu *to_dtpm_cpu(struct dtpm *dtpm) |
| { |
| return container_of(dtpm, struct dtpm_cpu, dtpm); |
| } |
| |
| static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit) |
| { |
| struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); |
| struct em_perf_domain *pd = em_cpu_get(dtpm_cpu->cpu); |
| struct cpumask cpus; |
| unsigned long freq; |
| u64 power; |
| int i, nr_cpus; |
| |
| 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 scale_pd_power_uw(struct cpumask *pd_mask, u64 power) |
| { |
| unsigned long max = 0, sum_util = 0; |
| int cpu; |
| |
| for_each_cpu_and(cpu, pd_mask, cpu_online_mask) { |
| |
| /* |
| * The capacity is the same for all CPUs belonging to |
| * the same perf domain, so a single call to |
| * arch_scale_cpu_capacity() is enough. However, we |
| * need the CPU parameter to be initialized by the |
| * loop, so the call ends up in this block. |
| * |
| * We can initialize 'max' with a cpumask_first() call |
| * before the loop but the bits computation is not |
| * worth given the arch_scale_cpu_capacity() just |
| * returns a value where the resulting assembly code |
| * will be optimized by the compiler. |
| */ |
| max = arch_scale_cpu_capacity(cpu); |
| sum_util += sched_cpu_util(cpu, max); |
| } |
| |
| /* |
| * In the improbable case where all the CPUs of the perf |
| * domain are offline, 'max' will be zero and will lead to an |
| * illegal operation with a zero division. |
| */ |
| return max ? (power * ((sum_util << 10) / max)) >> 10 : 0; |
| } |
| |
| static u64 get_pd_power_uw(struct dtpm *dtpm) |
| { |
| struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); |
| struct em_perf_domain *pd; |
| struct cpumask *pd_mask; |
| unsigned long freq; |
| int i; |
| |
| pd = em_cpu_get(dtpm_cpu->cpu); |
| |
| pd_mask = em_span_cpus(pd); |
| |
| freq = cpufreq_quick_get(dtpm_cpu->cpu); |
| |
| for (i = 0; i < pd->nr_perf_states; i++) { |
| |
| if (pd->table[i].frequency < freq) |
| continue; |
| |
| return scale_pd_power_uw(pd_mask, pd->table[i].power * |
| MICROWATT_PER_MILLIWATT); |
| } |
| |
| return 0; |
| } |
| |
| static int update_pd_power_uw(struct dtpm *dtpm) |
| { |
| struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); |
| struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu); |
| struct cpumask cpus; |
| int nr_cpus; |
| |
| cpumask_and(&cpus, cpu_online_mask, to_cpumask(em->cpus)); |
| nr_cpus = cpumask_weight(&cpus); |
| |
| dtpm->power_min = em->table[0].power; |
| dtpm->power_min *= MICROWATT_PER_MILLIWATT; |
| dtpm->power_min *= nr_cpus; |
| |
| dtpm->power_max = em->table[em->nr_perf_states - 1].power; |
| dtpm->power_max *= MICROWATT_PER_MILLIWATT; |
| dtpm->power_max *= nr_cpus; |
| |
| return 0; |
| } |
| |
| static void pd_release(struct dtpm *dtpm) |
| { |
| struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); |
| struct cpufreq_policy *policy; |
| |
| if (freq_qos_request_active(&dtpm_cpu->qos_req)) |
| freq_qos_remove_request(&dtpm_cpu->qos_req); |
| |
| policy = cpufreq_cpu_get(dtpm_cpu->cpu); |
| if (policy) { |
| for_each_cpu(dtpm_cpu->cpu, policy->related_cpus) |
| per_cpu(dtpm_per_cpu, dtpm_cpu->cpu) = NULL; |
| } |
| |
| kfree(dtpm_cpu); |
| } |
| |
| 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 cpuhp_dtpm_cpu_offline(unsigned int cpu) |
| { |
| struct dtpm_cpu *dtpm_cpu; |
| |
| dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); |
| if (dtpm_cpu) |
| dtpm_update_power(&dtpm_cpu->dtpm); |
| |
| return 0; |
| } |
| |
| static int cpuhp_dtpm_cpu_online(unsigned int cpu) |
| { |
| struct dtpm_cpu *dtpm_cpu; |
| |
| dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); |
| if (dtpm_cpu) |
| return dtpm_update_power(&dtpm_cpu->dtpm); |
| |
| return 0; |
| } |
| |
| static int __dtpm_cpu_setup(int cpu, struct dtpm *parent) |
| { |
| struct dtpm_cpu *dtpm_cpu; |
| struct cpufreq_policy *policy; |
| struct em_perf_domain *pd; |
| char name[CPUFREQ_NAME_LEN]; |
| int ret = -ENOMEM; |
| |
| dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); |
| if (dtpm_cpu) |
| return 0; |
| |
| policy = cpufreq_cpu_get(cpu); |
| if (!policy) |
| return 0; |
| |
| pd = em_cpu_get(cpu); |
| if (!pd || em_is_artificial(pd)) |
| return -EINVAL; |
| |
| dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL); |
| if (!dtpm_cpu) |
| return -ENOMEM; |
| |
| dtpm_init(&dtpm_cpu->dtpm, &dtpm_ops); |
| dtpm_cpu->cpu = cpu; |
| |
| for_each_cpu(cpu, policy->related_cpus) |
| per_cpu(dtpm_per_cpu, cpu) = dtpm_cpu; |
| |
| snprintf(name, sizeof(name), "cpu%d-cpufreq", dtpm_cpu->cpu); |
| |
| ret = dtpm_register(name, &dtpm_cpu->dtpm, parent); |
| if (ret) |
| goto out_kfree_dtpm_cpu; |
| |
| 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_dtpm_unregister; |
| |
| return 0; |
| |
| out_dtpm_unregister: |
| dtpm_unregister(&dtpm_cpu->dtpm); |
| dtpm_cpu = NULL; |
| |
| out_kfree_dtpm_cpu: |
| for_each_cpu(cpu, policy->related_cpus) |
| per_cpu(dtpm_per_cpu, cpu) = NULL; |
| kfree(dtpm_cpu); |
| |
| return ret; |
| } |
| |
| static int dtpm_cpu_setup(struct dtpm *dtpm, struct device_node *np) |
| { |
| int cpu; |
| |
| cpu = of_cpu_node_to_id(np); |
| if (cpu < 0) |
| return 0; |
| |
| return __dtpm_cpu_setup(cpu, dtpm); |
| } |
| |
| static int dtpm_cpu_init(void) |
| { |
| int ret; |
| |
| /* |
| * The callbacks at CPU hotplug time are calling |
| * dtpm_update_power() which in turns calls update_pd_power(). |
| * |
| * The function update_pd_power() uses the online mask to |
| * figure out the power consumption limits. |
| * |
| * At CPUHP_AP_ONLINE_DYN, the CPU is present in the CPU |
| * online mask when the cpuhp_dtpm_cpu_online function is |
| * called, but the CPU is still in the online mask for the |
| * tear down callback. So the power can not be updated when |
| * the CPU is unplugged. |
| * |
| * At CPUHP_AP_DTPM_CPU_DEAD, the situation is the opposite as |
| * above. The CPU online mask is not up to date when the CPU |
| * is plugged in. |
| * |
| * For this reason, we need to call the online and offline |
| * callbacks at different moments when the CPU online mask is |
| * consistent with the power numbers we want to update. |
| */ |
| ret = cpuhp_setup_state(CPUHP_AP_DTPM_CPU_DEAD, "dtpm_cpu:offline", |
| NULL, cpuhp_dtpm_cpu_offline); |
| if (ret < 0) |
| return ret; |
| |
| ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dtpm_cpu:online", |
| cpuhp_dtpm_cpu_online, NULL); |
| if (ret < 0) |
| return ret; |
| |
| return 0; |
| } |
| |
| static void dtpm_cpu_exit(void) |
| { |
| cpuhp_remove_state_nocalls(CPUHP_AP_ONLINE_DYN); |
| cpuhp_remove_state_nocalls(CPUHP_AP_DTPM_CPU_DEAD); |
| } |
| |
| struct dtpm_subsys_ops dtpm_cpu_ops = { |
| .name = KBUILD_MODNAME, |
| .init = dtpm_cpu_init, |
| .exit = dtpm_cpu_exit, |
| .setup = dtpm_cpu_setup, |
| }; |