perf_event_cpu.c
/*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) 2012 ARM Limited
*
* Author: Will Deacon <will.deacon@arm.com>
*/
#define pr_fmt(fmt) "CPU PMU: " fmt
#include <linux/bitmap.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <asm/cputype.h>
#include <asm/irq_regs.h>
#include <asm/pmu.h>
/* Set at runtime when we know what CPU type we are. */
static struct arm_pmu *cpu_pmu;
static DEFINE_PER_CPU(struct perf_event * [ARMPMU_MAX_HWEVENTS], hw_events);
static DEFINE_PER_CPU(unsigned long [BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)], used_mask);
static DEFINE_PER_CPU(struct pmu_hw_events, cpu_hw_events);
/*
* Despite the names, these two functions are CPU-specific and are used
* by the OProfile/perf code.
*/
const char *perf_pmu_name(void)
{
if (!cpu_pmu)
return NULL;
return cpu_pmu->name;
}
EXPORT_SYMBOL_GPL(perf_pmu_name);
int perf_num_counters(void)
{
int max_events = 0;
if (cpu_pmu != NULL)
max_events = cpu_pmu->num_events;
return max_events;
}
EXPORT_SYMBOL_GPL(perf_num_counters);
/* Include the PMU-specific implementations. */
#include "perf_event_xscale.c"
#include "perf_event_v6.c"
#include "perf_event_v7.c"
static struct pmu_hw_events *cpu_pmu_get_cpu_events(void)
{
return this_cpu_ptr(&cpu_hw_events);
}
static void cpu_pmu_free_irq(struct arm_pmu *cpu_pmu)
{
int i, irq, irqs;
struct platform_device *pmu_device = cpu_pmu->plat_device;
irqs = min(pmu_device->num_resources, num_possible_cpus());
for (i = 0; i < irqs; ++i) {
if (!cpumask_test_and_clear_cpu(i, &cpu_pmu->active_irqs))
continue;
irq = platform_get_irq(pmu_device, i);
if (irq >= 0)
free_irq(irq, cpu_pmu);
}
}
static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
{
int i, err, irq, irqs;
struct platform_device *pmu_device = cpu_pmu->plat_device;
if (!pmu_device)
return -ENODEV;
irqs = min(pmu_device->num_resources, num_possible_cpus());
if (irqs < 1) {
pr_err("no irqs for PMUs defined\n");
return -ENODEV;
}
for (i = 0; i < irqs; ++i) {
err = 0;
irq = platform_get_irq(pmu_device, i);
if (irq < 0)
continue;
/*
* If we have a single PMU interrupt that we can't shift,
* assume that we're running on a uniprocessor machine and
* continue. Otherwise, continue without this interrupt.
*/
if (irq_set_affinity(irq, cpumask_of(i)) && irqs > 1) {
pr_warning("unable to set irq affinity (irq=%d, cpu=%u)\n",
irq, i);
continue;
}
err = request_irq(irq, handler,
IRQF_NOBALANCING | IRQF_NO_THREAD, "arm-pmu",
cpu_pmu);
if (err) {
pr_err("unable to request IRQ%d for ARM PMU counters\n",
irq);
return err;
}
cpumask_set_cpu(i, &cpu_pmu->active_irqs);
}
return 0;
}
static void cpu_pmu_init(struct arm_pmu *cpu_pmu)
{
int cpu;
for_each_possible_cpu(cpu) {
struct pmu_hw_events *events = &per_cpu(cpu_hw_events, cpu);
events->events = per_cpu(hw_events, cpu);
events->used_mask = per_cpu(used_mask, cpu);
raw_spin_lock_init(&events->pmu_lock);
}
cpu_pmu->get_hw_events = cpu_pmu_get_cpu_events;
cpu_pmu->request_irq = cpu_pmu_request_irq;
cpu_pmu->free_irq = cpu_pmu_free_irq;
/* Ensure the PMU has sane values out of reset. */
if (cpu_pmu->reset)
on_each_cpu(cpu_pmu->reset, cpu_pmu, 1);
}
/*
* PMU hardware loses all context when a CPU goes offline.
* When a CPU is hotplugged back in, since some hardware registers are
* UNKNOWN at reset, the PMU must be explicitly reset to avoid reading
* junk values out of them.
*/
static int cpu_pmu_notify(struct notifier_block *b, unsigned long action,
void *hcpu)
{
if ((action & ~CPU_TASKS_FROZEN) != CPU_STARTING)
return NOTIFY_DONE;
if (cpu_pmu && cpu_pmu->reset)
cpu_pmu->reset(cpu_pmu);
else
return NOTIFY_DONE;
return NOTIFY_OK;
}
static struct notifier_block cpu_pmu_hotplug_notifier = {
.notifier_call = cpu_pmu_notify,
};
/*
* PMU platform driver and devicetree bindings.
*/
static struct of_device_id cpu_pmu_of_device_ids[] = {
{.compatible = "arm,cortex-a15-pmu", .data = armv7_a15_pmu_init},
{.compatible = "arm,cortex-a9-pmu", .data = armv7_a9_pmu_init},
{.compatible = "arm,cortex-a8-pmu", .data = armv7_a8_pmu_init},
{.compatible = "arm,cortex-a7-pmu", .data = armv7_a7_pmu_init},
{.compatible = "arm,cortex-a5-pmu", .data = armv7_a5_pmu_init},
{.compatible = "arm,arm11mpcore-pmu", .data = armv6mpcore_pmu_init},
{.compatible = "arm,arm1176-pmu", .data = armv6pmu_init},
{.compatible = "arm,arm1136-pmu", .data = armv6pmu_init},
{},
};
static struct platform_device_id cpu_pmu_plat_device_ids[] = {
{.name = "arm-pmu"},
{},
};
/*
* CPU PMU identification and probing.
*/
static int probe_current_pmu(struct arm_pmu *pmu)
{
int cpu = get_cpu();
unsigned long implementor = read_cpuid_implementor();
unsigned long part_number = read_cpuid_part_number();
int ret = -ENODEV;
pr_info("probing PMU on CPU %d\n", cpu);
/* ARM Ltd CPUs. */
if (implementor == ARM_CPU_IMP_ARM) {
switch (part_number) {
case ARM_CPU_PART_ARM1136:
case ARM_CPU_PART_ARM1156:
case ARM_CPU_PART_ARM1176:
ret = armv6pmu_init(pmu);
break;
case ARM_CPU_PART_ARM11MPCORE:
ret = armv6mpcore_pmu_init(pmu);
break;
case ARM_CPU_PART_CORTEX_A8:
ret = armv7_a8_pmu_init(pmu);
break;
case ARM_CPU_PART_CORTEX_A9:
ret = armv7_a9_pmu_init(pmu);
break;
case ARM_CPU_PART_CORTEX_A5:
ret = armv7_a5_pmu_init(pmu);
break;
case ARM_CPU_PART_CORTEX_A15:
ret = armv7_a15_pmu_init(pmu);
break;
case ARM_CPU_PART_CORTEX_A7:
ret = armv7_a7_pmu_init(pmu);
break;
}
/* Intel CPUs [xscale]. */
} else if (implementor == ARM_CPU_IMP_INTEL) {
switch (xscale_cpu_arch_version()) {
case ARM_CPU_XSCALE_ARCH_V1:
ret = xscale1pmu_init(pmu);
break;
case ARM_CPU_XSCALE_ARCH_V2:
ret = xscale2pmu_init(pmu);
break;
}
}
put_cpu();
return ret;
}
static int cpu_pmu_device_probe(struct platform_device *pdev)
{
const struct of_device_id *of_id;
int (*init_fn)(struct arm_pmu *);
struct device_node *node = pdev->dev.of_node;
struct arm_pmu *pmu;
int ret = -ENODEV;
if (cpu_pmu) {
pr_info("attempt to register multiple PMU devices!");
return -ENOSPC;
}
pmu = kzalloc(sizeof(struct arm_pmu), GFP_KERNEL);
if (!pmu) {
pr_info("failed to allocate PMU device!");
return -ENOMEM;
}
if (node && (of_id = of_match_node(cpu_pmu_of_device_ids, pdev->dev.of_node))) {
init_fn = of_id->data;
ret = init_fn(pmu);
} else {
ret = probe_current_pmu(pmu);
}
if (ret) {
pr_info("failed to probe PMU!");
goto out_free;
}
cpu_pmu = pmu;
cpu_pmu->plat_device = pdev;
cpu_pmu_init(cpu_pmu);
ret = armpmu_register(cpu_pmu, PERF_TYPE_RAW);
if (!ret)
return 0;
out_free:
pr_info("failed to register PMU devices!");
kfree(pmu);
return ret;
}
static struct platform_driver cpu_pmu_driver = {
.driver = {
.name = "arm-pmu",
.pm = &armpmu_dev_pm_ops,
.of_match_table = cpu_pmu_of_device_ids,
},
.probe = cpu_pmu_device_probe,
.id_table = cpu_pmu_plat_device_ids,
};
static int __init register_pmu_driver(void)
{
int err;
err = register_cpu_notifier(&cpu_pmu_hotplug_notifier);
if (err)
return err;
err = platform_driver_register(&cpu_pmu_driver);
if (err)
unregister_cpu_notifier(&cpu_pmu_hotplug_notifier);
return err;
}
device_initcall(register_pmu_driver);