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author | Jamie Iles <jamie.iles@picochip.com> | 2010-02-02 19:23:15 (GMT) |
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committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-02-12 17:23:43 (GMT) |
commit | 0f4f0672ac950c96cffaf84a666d35e817d7c3ca (patch) | |
tree | cb4c1ec72f7842622c636a76f5ca519f3f3e8ea8 /arch/arm/kernel/pmu.c | |
parent | 74d2e4f8d79ae0c4b6ec027958d5b18058662eea (diff) | |
download | linux-0f4f0672ac950c96cffaf84a666d35e817d7c3ca.tar.xz |
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>
Diffstat (limited to 'arch/arm/kernel/pmu.c')
-rw-r--r-- | arch/arm/kernel/pmu.c | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/arch/arm/kernel/pmu.c b/arch/arm/kernel/pmu.c new file mode 100644 index 0000000..a124312 --- /dev/null +++ b/arch/arm/kernel/pmu.c @@ -0,0 +1,103 @@ +/* + * 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); |