[PATCH 1/6] ARM: pmu: register IRQs at runtime
Will Deacon
will.deacon at arm.com
Thu Mar 25 11:16:33 EDT 2010
The current PMU infrastructure for ARM requires that the IRQs for the PMU
device are fixed at compile time and are selected based on the ARCH_ or MACH_
flags. This has the disadvantage of tying the Kernel down to a particular board
as far as profiling is concerned.
This patch replaces the compile-time IRQ registration with a runtime mechanism
which allows the IRQs to be registered with the framework as a platform_device.
A further advantage of this change is that there is scope for registering
different types of performance counters in the future by changing the id of
the platform_device and attaching different resources to it.
Cc: Russell King - ARM Linux <linux at arm.linux.org.uk>
Cc: Jamie Iles <jamie.iles at picochip.com>
Signed-off-by: Will Deacon <will.deacon at arm.com>
---
arch/arm/include/asm/pmu.h | 32 ++++++-----
arch/arm/kernel/perf_event.c | 36 ++++++------
arch/arm/kernel/pmu.c | 127 +++++++++++++++++++++++++++--------------
3 files changed, 119 insertions(+), 76 deletions(-)
diff --git a/arch/arm/include/asm/pmu.h b/arch/arm/include/asm/pmu.h
index 2829b9f..8ccea01 100644
--- a/arch/arm/include/asm/pmu.h
+++ b/arch/arm/include/asm/pmu.h
@@ -12,33 +12,33 @@
#ifndef __ARM_PMU_H__
#define __ARM_PMU_H__
-#ifdef CONFIG_CPU_HAS_PMU
-
-struct pmu_irqs {
- const int *irqs;
- int num_irqs;
+enum arm_pmu_type {
+ ARM_PMU_DEVICE_CPU = 0,
+ ARM_NUM_PMU_DEVICES,
};
+#ifdef CONFIG_CPU_HAS_PMU
+
/**
* reserve_pmu() - reserve the hardware performance counters
*
* Reserve the hardware performance counters in the system for exclusive use.
- * The 'struct pmu_irqs' for the system is returned on success, ERR_PTR()
+ * The platform_device for the system is returned on success, ERR_PTR()
* encoded error on failure.
*/
-extern const struct pmu_irqs *
-reserve_pmu(void);
+extern struct platform_device *
+reserve_pmu(enum arm_pmu_type device);
/**
* release_pmu() - Relinquish control of the performance counters
*
* Release the performance counters and allow someone else to use them.
* Callers must have disabled the counters and released IRQs before calling
- * this. The 'struct pmu_irqs' returned from reserve_pmu() must be passed as
+ * this. The platform_device returned from reserve_pmu() must be passed as
* a cookie.
*/
extern int
-release_pmu(const struct pmu_irqs *irqs);
+release_pmu(struct platform_device *pdev);
/**
* init_pmu() - Initialise the PMU.
@@ -48,24 +48,26 @@ release_pmu(const struct pmu_irqs *irqs);
* the actual hardware initialisation.
*/
extern int
-init_pmu(void);
+init_pmu(enum arm_pmu_type device);
#else /* CONFIG_CPU_HAS_PMU */
-static inline const struct pmu_irqs *
-reserve_pmu(void)
+#include <linux/err.h>
+
+static inline struct platform_device *
+reserve_pmu(enum arm_pmu_type device)
{
return ERR_PTR(-ENODEV);
}
static inline int
-release_pmu(const struct pmu_irqs *irqs)
+release_pmu(struct platform_device *pdev)
{
return -ENODEV;
}
static inline int
-init_pmu(void)
+init_pmu(enum arm_pmu_type device)
{
return -ENODEV;
}
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index 9e70f20..0c1a447 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -17,6 +17,7 @@
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/perf_event.h>
+#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
@@ -26,7 +27,7 @@
#include <asm/pmu.h>
#include <asm/stacktrace.h>
-static const struct pmu_irqs *pmu_irqs;
+static struct platform_device *pmu_device;
/*
* Hardware lock to serialize accesses to PMU registers. Needed for the
@@ -317,35 +318,36 @@ armpmu_reserve_hardware(void)
int i;
int err;
- pmu_irqs = reserve_pmu();
- if (IS_ERR(pmu_irqs)) {
+ pmu_device = reserve_pmu(ARM_PMU_DEVICE_CPU);
+ if (IS_ERR(pmu_device)) {
pr_warning("unable to reserve pmu\n");
- return PTR_ERR(pmu_irqs);
+ return PTR_ERR(pmu_device);
}
- init_pmu();
+ init_pmu(ARM_PMU_DEVICE_CPU);
- if (pmu_irqs->num_irqs < 1) {
+ if (pmu_device->num_resources < 1) {
pr_err("no irqs for PMUs defined\n");
return -ENODEV;
}
- for (i = 0; i < pmu_irqs->num_irqs; ++i) {
- err = request_irq(pmu_irqs->irqs[i], armpmu->handle_irq,
+ for (i = 0; i < pmu_device->num_resources; ++i) {
+ err = request_irq(platform_get_irq(pmu_device, i),
+ armpmu->handle_irq,
IRQF_DISABLED | IRQF_NOBALANCING,
"armpmu", NULL);
if (err) {
- pr_warning("unable to request IRQ%d for ARM "
- "perf counters\n", pmu_irqs->irqs[i]);
+ pr_warning("unable to request IRQ%d for ARM perf "
+ "counters\n", platform_get_irq(pmu_device, i));
break;
}
}
if (err) {
for (i = i - 1; i >= 0; --i)
- free_irq(pmu_irqs->irqs[i], NULL);
- release_pmu(pmu_irqs);
- pmu_irqs = NULL;
+ free_irq(platform_get_irq(pmu_device, i), NULL);
+ release_pmu(pmu_device);
+ pmu_device = NULL;
}
return err;
@@ -356,12 +358,12 @@ armpmu_release_hardware(void)
{
int i;
- for (i = pmu_irqs->num_irqs - 1; i >= 0; --i)
- free_irq(pmu_irqs->irqs[i], NULL);
+ for (i = pmu_device->num_resources - 1; i >= 0; --i)
+ free_irq(platform_get_irq(pmu_device, i), NULL);
armpmu->stop();
- release_pmu(pmu_irqs);
- pmu_irqs = NULL;
+ release_pmu(pmu_device);
+ pmu_device = NULL;
}
static atomic_t active_events = ATOMIC_INIT(0);
diff --git a/arch/arm/kernel/pmu.c b/arch/arm/kernel/pmu.c
index a124312..b8af96e 100644
--- a/arch/arm/kernel/pmu.c
+++ b/arch/arm/kernel/pmu.c
@@ -2,6 +2,7 @@
* 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
@@ -9,65 +10,78 @@
*
*/
+#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>
-/*
- * 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 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);
-static const struct pmu_irqs pmu_irqs = {
- .irqs = irqs,
- .num_irqs = ARRAY_SIZE(irqs),
+ pmu_devices[pdev->id] = pdev;
+ return 0;
+}
+
+static struct platform_driver pmu_driver = {
+ .driver = {
+ .name = "arm-pmu",
+ },
+ .probe = pmu_device_probe,
};
-static volatile long pmu_lock;
+static int __init register_pmu_driver(void)
+{
+ return platform_driver_register(&pmu_driver);
+}
+device_initcall(register_pmu_driver);
-const struct pmu_irqs *
-reserve_pmu(void)
+struct platform_device *
+reserve_pmu(enum arm_pmu_type device)
{
- return test_and_set_bit_lock(0, &pmu_lock) ? ERR_PTR(-EBUSY) :
- &pmu_irqs;
+ 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(const struct pmu_irqs *irqs)
+release_pmu(struct platform_device *pdev)
{
- if (WARN_ON(irqs != &pmu_irqs))
+ if (WARN_ON(pdev != pmu_devices[pdev->id]))
return -EINVAL;
- clear_bit_unlock(0, &pmu_lock);
+ clear_bit_unlock(pdev->id, &pmu_lock);
return 0;
}
EXPORT_SYMBOL_GPL(release_pmu);
@@ -87,17 +101,42 @@ set_irq_affinity(int irq,
#endif
}
-int
-init_pmu(void)
+static int
+init_cpu_pmu(void)
{
int i, err = 0;
+ struct platform_device *pdev = pmu_devices[ARM_PMU_DEVICE_CPU];
+
+ if (!pdev) {
+ err = -ENODEV;
+ goto out;
+ }
- for (i = 0; i < pmu_irqs.num_irqs; ++i) {
- err = set_irq_affinity(pmu_irqs.irqs[i], i);
+ for (i = 0; i < pdev->num_resources; ++i) {
+ err = set_irq_affinity(platform_get_irq(pdev, i), i);
if (err)
break;
}
+out:
+ 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);
--
1.6.3.3
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