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>
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);