--- /dev/null
+/*
+ * Performance events - AMD Processor Power Reporting Mechanism
+ *
+ * Copyright (C) 2016 Advanced Micro Devices, Inc.
+ *
+ * Author: Huang Rui <ray.huang@amd.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/perf_event.h>
+#include <asm/cpu_device_id.h>
+#include "../perf_event.h"
+
+#define MSR_F15H_CU_PWR_ACCUMULATOR 0xc001007a
+#define MSR_F15H_CU_MAX_PWR_ACCUMULATOR 0xc001007b
+#define MSR_F15H_PTSC 0xc0010280
+
+/* Event code: LSB 8 bits, passed in attr->config any other bit is reserved. */
+#define AMD_POWER_EVENT_MASK 0xFFULL
+
+/*
+ * Accumulated power status counters.
+ */
+#define AMD_POWER_EVENTSEL_PKG 1
+
+/*
+ * The ratio of compute unit power accumulator sample period to the
+ * PTSC period.
+ */
+static unsigned int cpu_pwr_sample_ratio;
+
+/* Maximum accumulated power of a compute unit. */
+static u64 max_cu_acc_power;
+
+static struct pmu pmu_class;
+
+/*
+ * Accumulated power represents the sum of each compute unit's (CU) power
+ * consumption. On any core of each CU we read the total accumulated power from
+ * MSR_F15H_CU_PWR_ACCUMULATOR. cpu_mask represents CPU bit map of all cores
+ * which are picked to measure the power for the CUs they belong to.
+ */
+static cpumask_t cpu_mask;
+
+static void event_update(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ u64 prev_pwr_acc, new_pwr_acc, prev_ptsc, new_ptsc;
+ u64 delta, tdelta;
+
+ prev_pwr_acc = hwc->pwr_acc;
+ prev_ptsc = hwc->ptsc;
+ rdmsrl(MSR_F15H_CU_PWR_ACCUMULATOR, new_pwr_acc);
+ rdmsrl(MSR_F15H_PTSC, new_ptsc);
+
+ /*
+ * Calculate the CU power consumption over a time period, the unit of
+ * final value (delta) is micro-Watts. Then add it to the event count.
+ */
+ if (new_pwr_acc < prev_pwr_acc) {
+ delta = max_cu_acc_power + new_pwr_acc;
+ delta -= prev_pwr_acc;
+ } else
+ delta = new_pwr_acc - prev_pwr_acc;
+
+ delta *= cpu_pwr_sample_ratio * 1000;
+ tdelta = new_ptsc - prev_ptsc;
+
+ do_div(delta, tdelta);
+ local64_add(delta, &event->count);
+}
+
+static void __pmu_event_start(struct perf_event *event)
+{
+ if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED)))
+ return;
+
+ event->hw.state = 0;
+
+ rdmsrl(MSR_F15H_PTSC, event->hw.ptsc);
+ rdmsrl(MSR_F15H_CU_PWR_ACCUMULATOR, event->hw.pwr_acc);
+}
+
+static void pmu_event_start(struct perf_event *event, int mode)
+{
+ __pmu_event_start(event);
+}
+
+static void pmu_event_stop(struct perf_event *event, int mode)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ /* Mark event as deactivated and stopped. */
+ if (!(hwc->state & PERF_HES_STOPPED))
+ hwc->state |= PERF_HES_STOPPED;
+
+ /* Check if software counter update is necessary. */
+ if ((mode & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
+ /*
+ * Drain the remaining delta count out of an event
+ * that we are disabling:
+ */
+ event_update(event);
+ hwc->state |= PERF_HES_UPTODATE;
+ }
+}
+
+static int pmu_event_add(struct perf_event *event, int mode)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
+
+ if (mode & PERF_EF_START)
+ __pmu_event_start(event);
+
+ return 0;
+}
+
+static void pmu_event_del(struct perf_event *event, int flags)
+{
+ pmu_event_stop(event, PERF_EF_UPDATE);
+}
+
+static int pmu_event_init(struct perf_event *event)
+{
+ u64 cfg = event->attr.config & AMD_POWER_EVENT_MASK;
+
+ /* Only look at AMD power events. */
+ if (event->attr.type != pmu_class.type)
+ return -ENOENT;
+
+ /* Unsupported modes and filters. */
+ if (event->attr.exclude_user ||
+ event->attr.exclude_kernel ||
+ event->attr.exclude_hv ||
+ event->attr.exclude_idle ||
+ event->attr.exclude_host ||
+ event->attr.exclude_guest ||
+ /* no sampling */
+ event->attr.sample_period)
+ return -EINVAL;
+
+ if (cfg != AMD_POWER_EVENTSEL_PKG)
+ return -EINVAL;
+
+ return 0;
+}
+
+static void pmu_event_read(struct perf_event *event)
+{
+ event_update(event);
+}
+
+static ssize_t
+get_attr_cpumask(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return cpumap_print_to_pagebuf(true, buf, &cpu_mask);
+}
+
+static DEVICE_ATTR(cpumask, S_IRUGO, get_attr_cpumask, NULL);
+
+static struct attribute *pmu_attrs[] = {
+ &dev_attr_cpumask.attr,
+ NULL,
+};
+
+static struct attribute_group pmu_attr_group = {
+ .attrs = pmu_attrs,
+};
+
+/*
+ * Currently it only supports to report the power of each
+ * processor/package.
+ */
+EVENT_ATTR_STR(power-pkg, power_pkg, "event=0x01");
+
+EVENT_ATTR_STR(power-pkg.unit, power_pkg_unit, "mWatts");
+
+/* Convert the count from micro-Watts to milli-Watts. */
+EVENT_ATTR_STR(power-pkg.scale, power_pkg_scale, "1.000000e-3");
+
+static struct attribute *events_attr[] = {
+ EVENT_PTR(power_pkg),
+ EVENT_PTR(power_pkg_unit),
+ EVENT_PTR(power_pkg_scale),
+ NULL,
+};
+
+static struct attribute_group pmu_events_group = {
+ .name = "events",
+ .attrs = events_attr,
+};
+
+PMU_FORMAT_ATTR(event, "config:0-7");
+
+static struct attribute *formats_attr[] = {
+ &format_attr_event.attr,
+ NULL,
+};
+
+static struct attribute_group pmu_format_group = {
+ .name = "format",
+ .attrs = formats_attr,
+};
+
+static const struct attribute_group *attr_groups[] = {
+ &pmu_attr_group,
+ &pmu_format_group,
+ &pmu_events_group,
+ NULL,
+};
+
+static struct pmu pmu_class = {
+ .attr_groups = attr_groups,
+ /* system-wide only */
+ .task_ctx_nr = perf_invalid_context,
+ .event_init = pmu_event_init,
+ .add = pmu_event_add,
+ .del = pmu_event_del,
+ .start = pmu_event_start,
+ .stop = pmu_event_stop,
+ .read = pmu_event_read,
+};
+
+static void power_cpu_exit(int cpu)
+{
+ int target;
+
+ if (!cpumask_test_and_clear_cpu(cpu, &cpu_mask))
+ return;
+
+ /*
+ * Find a new CPU on the same compute unit, if was set in cpumask
+ * and still some CPUs on compute unit. Then migrate event and
+ * context to new CPU.
+ */
+ target = cpumask_any_but(topology_sibling_cpumask(cpu), cpu);
+ if (target < nr_cpumask_bits) {
+ cpumask_set_cpu(target, &cpu_mask);
+ perf_pmu_migrate_context(&pmu_class, cpu, target);
+ }
+}
+
+static void power_cpu_init(int cpu)
+{
+ int target;
+
+ /*
+ * 1) If any CPU is set at cpu_mask in the same compute unit, do
+ * nothing.
+ * 2) If no CPU is set at cpu_mask in the same compute unit,
+ * set current STARTING CPU.
+ *
+ * Note: if there is a CPU aside of the new one already in the
+ * sibling mask, then it is also in cpu_mask.
+ */
+ target = cpumask_any_but(topology_sibling_cpumask(cpu), cpu);
+ if (target >= nr_cpumask_bits)
+ cpumask_set_cpu(cpu, &cpu_mask);
+}
+
+static int
+power_cpu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (long)hcpu;
+
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_DOWN_FAILED:
+ case CPU_STARTING:
+ power_cpu_init(cpu);
+ break;
+ case CPU_DOWN_PREPARE:
+ power_cpu_exit(cpu);
+ break;
+ default:
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block power_cpu_notifier_nb = {
+ .notifier_call = power_cpu_notifier,
+ .priority = CPU_PRI_PERF,
+};
+
+static const struct x86_cpu_id cpu_match[] = {
+ { .vendor = X86_VENDOR_AMD, .family = 0x15 },
+ {},
+};
+
+static int __init amd_power_pmu_init(void)
+{
+ int cpu, target, ret;
+
+ if (!x86_match_cpu(cpu_match))
+ return 0;
+
+ if (!boot_cpu_has(X86_FEATURE_ACC_POWER))
+ return -ENODEV;
+
+ cpu_pwr_sample_ratio = cpuid_ecx(0x80000007);
+
+ if (rdmsrl_safe(MSR_F15H_CU_MAX_PWR_ACCUMULATOR, &max_cu_acc_power)) {
+ pr_err("Failed to read max compute unit power accumulator MSR\n");
+ return -ENODEV;
+ }
+
+ cpu_notifier_register_begin();
+
+ /* Choose one online core of each compute unit. */
+ for_each_online_cpu(cpu) {
+ target = cpumask_first(topology_sibling_cpumask(cpu));
+ if (!cpumask_test_cpu(target, &cpu_mask))
+ cpumask_set_cpu(target, &cpu_mask);
+ }
+
+ ret = perf_pmu_register(&pmu_class, "power", -1);
+ if (WARN_ON(ret)) {
+ pr_warn("AMD Power PMU registration failed\n");
+ goto out;
+ }
+
+ __register_cpu_notifier(&power_cpu_notifier_nb);
+
+ pr_info("AMD Power PMU detected\n");
+
+out:
+ cpu_notifier_register_done();
+
+ return ret;
+}
+module_init(amd_power_pmu_init);
+
+static void __exit amd_power_pmu_exit(void)
+{
+ cpu_notifier_register_begin();
+ __unregister_cpu_notifier(&power_cpu_notifier_nb);
+ cpu_notifier_register_done();
+
+ perf_pmu_unregister(&pmu_class);
+}
+module_exit(amd_power_pmu_exit);
+
+MODULE_AUTHOR("Huang Rui <ray.huang@amd.com>");
+MODULE_DESCRIPTION("AMD Processor Power Reporting Mechanism");
+MODULE_LICENSE("GPL v2");
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