arch/arm/kernel/perf_event_cpu.c - maze/linux - Git at Google

 /*
  * 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 <linux/irq.h>
 #include <linux/irqdesc.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 arm_pmu *, percpu_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_enable_percpu_irq(void *data)
 {
 	struct arm_pmu *cpu_pmu = data;
 	struct platform_device *pmu_device = cpu_pmu->plat_device;
 	int irq = platform_get_irq(pmu_device, 0);

 	enable_percpu_irq(irq, IRQ_TYPE_NONE);
 	cpumask_set_cpu(smp_processor_id(), &cpu_pmu->active_irqs);
 }

 static void cpu_pmu_disable_percpu_irq(void *data)
 {
 	struct arm_pmu *cpu_pmu = data;
 	struct platform_device *pmu_device = cpu_pmu->plat_device;
 	int irq = platform_get_irq(pmu_device, 0);

 	cpumask_clear_cpu(smp_processor_id(), &cpu_pmu->active_irqs);
 	disable_percpu_irq(irq);
 }

 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());

 	irq = platform_get_irq(pmu_device, 0);
 	if (irq >= 0 && irq_is_percpu(irq)) {
 		on_each_cpu(cpu_pmu_disable_percpu_irq, cpu_pmu, 1);
 		free_percpu_irq(irq, &percpu_pmu);
 	} else {
 		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;
 	}

 	irq = platform_get_irq(pmu_device, 0);
 	if (irq >= 0 && irq_is_percpu(irq)) {
 		err = request_percpu_irq(irq, handler, "arm-pmu", &percpu_pmu);
 		if (err) {
 			pr_err("unable to request IRQ%d for ARM PMU counters\n",
 				irq);
 			return err;
 		}
 		on_each_cpu(cpu_pmu_enable_percpu_irq, cpu_pmu, 1);
 	} else {
 		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);
 		per_cpu(percpu_pmu, cpu) = cpu_pmu;
 	}

 	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-a12-pmu",	.data = armv7_a12_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},
 	{.compatible = "qcom,krait-pmu",	.data = krait_pmu_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;
 		}
 	/* 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;
 	const 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;
 	}

 	cpu_pmu = pmu;
 	cpu_pmu->plat_device = pdev;

 	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_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);
	/*
	* 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 <linux/irq.h>
	#include <linux/irqdesc.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 arm_pmu *, percpu_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_enable_percpu_irq(void *data)
	{
	struct arm_pmu *cpu_pmu = data;
	struct platform_device *pmu_device = cpu_pmu->plat_device;
	int irq = platform_get_irq(pmu_device, 0);

	enable_percpu_irq(irq, IRQ_TYPE_NONE);
	cpumask_set_cpu(smp_processor_id(), &cpu_pmu->active_irqs);
	}

	static void cpu_pmu_disable_percpu_irq(void *data)
	{
	struct arm_pmu *cpu_pmu = data;
	struct platform_device *pmu_device = cpu_pmu->plat_device;
	int irq = platform_get_irq(pmu_device, 0);

	cpumask_clear_cpu(smp_processor_id(), &cpu_pmu->active_irqs);
	disable_percpu_irq(irq);
	}

	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());

	irq = platform_get_irq(pmu_device, 0);
	if (irq >= 0 && irq_is_percpu(irq)) {
	on_each_cpu(cpu_pmu_disable_percpu_irq, cpu_pmu, 1);
	free_percpu_irq(irq, &percpu_pmu);
	} else {
	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;
	}

	irq = platform_get_irq(pmu_device, 0);
	if (irq >= 0 && irq_is_percpu(irq)) {
	err = request_percpu_irq(irq, handler, "arm-pmu", &percpu_pmu);
	if (err) {
	pr_err("unable to request IRQ%d for ARM PMU counters\n",
	irq);
	return err;
	}
	on_each_cpu(cpu_pmu_enable_percpu_irq, cpu_pmu, 1);
	} else {
	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);
	per_cpu(percpu_pmu, cpu) = cpu_pmu;
	}

	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-a12-pmu", .data = armv7_a12_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},
	{.compatible = "qcom,krait-pmu", .data = krait_pmu_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;
	}
	/* 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;
	const 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;
	}

	cpu_pmu = pmu;
	cpu_pmu->plat_device = pdev;

	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_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);