linux/arch/arm/kernel/pmu.c
Jamie Iles 0f4f0672ac ARM: 5899/2: arm: provide a mechanism to reserve performance counters
To add support for perf events and to allow the hardware counters to be
shared with oprofile, we need a way to reserve access to the pmu
(performance monitor unit). Platforms with PMU interrupts should
register the interrupts in arch/arm/kernel/pmu.c

Signed-off-by: Jamie Iles <jamie.iles@picochip.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-02-12 17:23:43 +00:00

104 lines
2.2 KiB
C

/*
* linux/arch/arm/kernel/pmu.c
*
* Copyright (C) 2009 picoChip Designs Ltd, Jamie Iles
*
* 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/cpumask.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/pmu.h>
/*
* Define the IRQs for the system. We could use something like a platform
* device but that seems fairly heavyweight for this. Also, the performance
* counters can't be removed or hotplugged.
*
* Ordering is important: init_pmu() will use the ordering to set the affinity
* to the corresponding core. e.g. the first interrupt will go to cpu 0, the
* second goes to cpu 1 etc.
*/
static const int irqs[] = {
#if defined(CONFIG_ARCH_OMAP2)
3,
#elif defined(CONFIG_ARCH_BCMRING)
IRQ_PMUIRQ,
#elif defined(CONFIG_MACH_REALVIEW_EB)
IRQ_EB11MP_PMU_CPU0,
IRQ_EB11MP_PMU_CPU1,
IRQ_EB11MP_PMU_CPU2,
IRQ_EB11MP_PMU_CPU3,
#elif defined(CONFIG_ARCH_OMAP3)
INT_34XX_BENCH_MPU_EMUL,
#elif defined(CONFIG_ARCH_IOP32X)
IRQ_IOP32X_CORE_PMU,
#elif defined(CONFIG_ARCH_IOP33X)
IRQ_IOP33X_CORE_PMU,
#elif defined(CONFIG_ARCH_PXA)
IRQ_PMU,
#endif
};
static const struct pmu_irqs pmu_irqs = {
.irqs = irqs,
.num_irqs = ARRAY_SIZE(irqs),
};
static volatile long pmu_lock;
const struct pmu_irqs *
reserve_pmu(void)
{
return test_and_set_bit_lock(0, &pmu_lock) ? ERR_PTR(-EBUSY) :
&pmu_irqs;
}
EXPORT_SYMBOL_GPL(reserve_pmu);
int
release_pmu(const struct pmu_irqs *irqs)
{
if (WARN_ON(irqs != &pmu_irqs))
return -EINVAL;
clear_bit_unlock(0, &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 0;
#endif
}
int
init_pmu(void)
{
int i, err = 0;
for (i = 0; i < pmu_irqs.num_irqs; ++i) {
err = set_irq_affinity(pmu_irqs.irqs[i], i);
if (err)
break;
}
return err;
}
EXPORT_SYMBOL_GPL(init_pmu);