1 files changed, 302 insertions, 0 deletions
diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c
new file mode 100644
index 000000000..9193c3b8e
--- /dev/null
+++ b/drivers/powercap/dtpm_cpu.c
@@ -0,0 +1,302 @@
+// 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>
+
+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 * 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 * nr_cpus;
+
+	return power_limit;
+}
+
+static u64 scale_pd_power_uw(struct cpumask *pd_mask, u64 power)
+{
+	unsigned long max, sum_util = 0;
+	int cpu;
+
+	/*
+	 * The capacity is the same for all CPUs belonging to
+	 * the same perf domain.
+	 */
+	max = arch_scale_cpu_capacity(cpumask_first(pd_mask));
+
+	for_each_cpu_and(cpu, pd_mask, cpu_online_mask)
+		sum_util += sched_cpu_util(cpu);
+
+	return (power * ((sum_util << 10) / max)) >> 10;
+}
+
+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);
+	}
+
+	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 *= nr_cpus;
+
+	dtpm->power_max = em->table[em->nr_perf_states - 1].power;
+	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;
+
+		cpufreq_cpu_put(policy);
+	}
+	
+	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)) {
+		ret = -EINVAL;
+		goto release_policy;
+	}
+
+	dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL);
+	if (!dtpm_cpu) {
+		ret = -ENOMEM;
+		goto release_policy;
+	}
+
+	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;
+
+	cpufreq_cpu_put(policy);
+	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);
+
+release_policy:
+	cpufreq_cpu_put(policy);
+	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,
+};