linux/arch/arm/kernel/pmu.c
Will Deacon 71efb063f4 ARM: 6742/1: pmu: avoid setting IRQ affinity on UP systems
Now that we can execute a CONFIG_SMP kernel on a uniprocessor system,
extra care has to be taken in the PMU IRQ affinity setting code to
ensure that we don't always fail to initialise.

This patch changes the CPU PMU initialisation code so that when we
only have a single IRQ, whose affinity can not be changed at the
controller, we report success (0) rather than -EINVAL.

Reported-by: Avik Sil <avik.sil@linaro.org>
Acked-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-02-19 11:24:05 +00:00

149 lines
3.0 KiB
C

/*
* 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);