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/*
* linux/arch/arm/kernel/pmu.c
*
* Copyright (C) 2009 picoChip Designs Ltd, Jamie Iles
* Copyright (C) 2010 ARM Ltd, Will Deacon
*
* 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.
*
*/
#define pr_fmt(fmt) "PMU: " fmt
#include <linux/cpumask.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <asm/pmu.h>
static volatile long pmu_lock;
static struct platform_device *pmu_devices[ARM_NUM_PMU_DEVICES];
static int __devinit pmu_device_probe(struct platform_device *pdev)
{
if (pdev->id < 0 || pdev->id >= ARM_NUM_PMU_DEVICES) {
pr_warning("received registration request for unknown "
"device %d\n", pdev->id);
return -EINVAL;
}
if (pmu_devices[pdev->id])
pr_warning("registering new PMU device type %d overwrites "
"previous registration!\n", pdev->id);
else
pr_info("registered new PMU device of type %d\n",
pdev->id);
pmu_devices[pdev->id] = pdev;
return 0;
}
static struct platform_driver pmu_driver = {
.driver = {
.name = "arm-pmu",
},
.probe = pmu_device_probe,
};
static int __init register_pmu_driver(void)
{
return platform_driver_register(&pmu_driver);
}
device_initcall(register_pmu_driver);
struct platform_device *
reserve_pmu(enum arm_pmu_type device)
{
struct platform_device *pdev;
if (test_and_set_bit_lock(device, &pmu_lock)) {
pdev = ERR_PTR(-EBUSY);
} else if (pmu_devices[device] == NULL) {
clear_bit_unlock(device, &pmu_lock);
pdev = ERR_PTR(-ENODEV);
} else {
pdev = pmu_devices[device];
}
return pdev;
}
EXPORT_SYMBOL_GPL(reserve_pmu);
int
release_pmu(struct platform_device *pdev)
{
if (WARN_ON(pdev != pmu_devices[pdev->id]))
return -EINVAL;
clear_bit_unlock(pdev->id, &pmu_lock);
return 0;
}
EXPORT_SYMBOL_GPL(release_pmu);
static int
set_irq_affinity(int irq,
unsigned int cpu)
{
#ifdef CONFIG_SMP
int err = irq_set_affinity(irq, cpumask_of(cpu));
if (err)
pr_warning("unable to set irq affinity (irq=%d, cpu=%u)\n",
irq, cpu);
return err;
#else
return -EINVAL;
#endif
}
static int
init_cpu_pmu(void)
{
int i, irqs, err = 0;
struct platform_device *pdev = pmu_devices[ARM_PMU_DEVICE_CPU];
if (!pdev)
return -ENODEV;
irqs = pdev->num_resources;
/*
* If we have a single PMU interrupt that we can't shift, assume that
* we're running on a uniprocessor machine and continue.
*/
if (irqs == 1 && !irq_can_set_affinity(platform_get_irq(pdev, 0)))
return 0;
for (i = 0; i < irqs; ++i) {
err = set_irq_affinity(platform_get_irq(pdev, i), i);
if (err)
break;
}
return err;
}
int
init_pmu(enum arm_pmu_type device)
{
int err = 0;
switch (device) {
case ARM_PMU_DEVICE_CPU:
err = init_cpu_pmu();
break;
default:
pr_warning("attempt to initialise unknown device %d\n",
device);
err = -EINVAL;
}
return err;
}
EXPORT_SYMBOL_GPL(init_pmu);
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