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Subject[PATCH 17/19] clocksource: mips-gic: Use CPU notifiers to setup the timer
Date
Instead of requiring an explicit call to gic_clockevent_init in the SMP
startup path, use CPU notifiers to register and enable the GIC timer on
CPU startup.

Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
---
arch/mips/include/asm/time.h | 5 +--
drivers/clocksource/mips-gic-timer.c | 60 ++++++++++++++++++++++++++----------
2 files changed, 45 insertions(+), 20 deletions(-)

diff --git a/arch/mips/include/asm/time.h b/arch/mips/include/asm/time.h
index 5f30aab..8ab2874 100644
--- a/arch/mips/include/asm/time.h
+++ b/arch/mips/include/asm/time.h
@@ -53,13 +53,10 @@ extern int __weak get_c0_perfcount_int(void);
*/
extern unsigned int __weak get_c0_compare_int(void);
extern int r4k_clockevent_init(void);
-extern int gic_clockevent_init(void);

static inline int mips_clockevent_init(void)
{
-#if defined(CONFIG_CLKSRC_MIPS_GIC)
- return (gic_clockevent_init() | r4k_clockevent_init());
-#elif defined(CONFIG_CEVT_R4K)
+#ifdef CONFIG_CEVT_R4K
return r4k_clockevent_init();
#else
return -ENXIO;
diff --git a/drivers/clocksource/mips-gic-timer.c b/drivers/clocksource/mips-gic-timer.c
index 05bdfe1..3ce992b 100644
--- a/drivers/clocksource/mips-gic-timer.c
+++ b/drivers/clocksource/mips-gic-timer.c
@@ -6,9 +6,11 @@
* Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
*/
#include <linux/clockchips.h>
+#include <linux/cpu.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irqchip/mips-gic.h>
+#include <linux/notifier.h>
#include <linux/percpu.h>
#include <linux/smp.h>
#include <linux/time.h>
@@ -16,7 +18,7 @@
#include <asm/time.h>

static DEFINE_PER_CPU(struct clock_event_device, gic_clockevent_device);
-static int gic_timer_irq_installed;
+static int gic_timer_irq;
static unsigned int gic_frequency;

static int gic_next_event(unsigned long delta, struct clock_event_device *evt)
@@ -53,18 +55,9 @@ struct irqaction gic_compare_irqaction = {
.name = "timer",
};

-int gic_clockevent_init(void)
+static void gic_clockevent_cpu_init(struct clock_event_device *cd)
{
unsigned int cpu = smp_processor_id();
- struct clock_event_device *cd;
- unsigned int irq;
-
- if (!cpu_has_counter || !gic_frequency)
- return -ENXIO;
-
- irq = MIPS_GIC_IRQ_BASE + GIC_LOCAL_TO_HWIRQ(GIC_LOCAL_INT_COMPARE);
-
- cd = &per_cpu(gic_clockevent_device, cpu);

cd->name = "MIPS GIC";
cd->features = CLOCK_EVT_FEAT_ONESHOT |
@@ -77,19 +70,52 @@ int gic_clockevent_init(void)
cd->min_delta_ns = clockevent_delta2ns(0x300, cd);

cd->rating = 300;
- cd->irq = irq;
+ cd->irq = gic_timer_irq;
cd->cpumask = cpumask_of(cpu);
cd->set_next_event = gic_next_event;
cd->set_mode = gic_set_clock_mode;

clockevents_register_device(cd);

- if (!gic_timer_irq_installed) {
- setup_percpu_irq(irq, &gic_compare_irqaction);
- gic_timer_irq_installed = 1;
+ enable_percpu_irq(gic_timer_irq, IRQ_TYPE_NONE);
+}
+
+static void gic_clockevent_cpu_exit(struct clock_event_device *cd)
+{
+ disable_percpu_irq(gic_timer_irq);
+}
+
+static int gic_cpu_notifier(struct notifier_block *nb, unsigned long action,
+ void *data)
+{
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_STARTING:
+ gic_clockevent_cpu_init(this_cpu_ptr(&gic_clockevent_device));
+ break;
+ case CPU_DYING:
+ gic_clockevent_cpu_exit(this_cpu_ptr(&gic_clockevent_device));
+ break;
}

- enable_percpu_irq(irq, IRQ_TYPE_NONE);
+ return NOTIFY_OK;
+}
+
+static struct notifier_block gic_cpu_nb = {
+ .notifier_call = gic_cpu_notifier,
+};
+
+static int gic_clockevent_init(void)
+{
+ if (!cpu_has_counter || !gic_frequency)
+ return -ENXIO;
+
+ gic_timer_irq = MIPS_GIC_IRQ_BASE +
+ GIC_LOCAL_TO_HWIRQ(GIC_LOCAL_INT_COMPARE);
+ setup_percpu_irq(gic_timer_irq, &gic_compare_irqaction);
+
+ register_cpu_notifier(&gic_cpu_nb);
+
+ gic_clockevent_cpu_init(this_cpu_ptr(&gic_clockevent_device));

return 0;
}
@@ -116,4 +142,6 @@ void __init gic_clocksource_init(unsigned int frequency)
gic_clocksource.rating = 200 + frequency / 10000000;

clocksource_register_hz(&gic_clocksource, frequency);
+
+ gic_clockevent_init();
}
--
2.1.0.rc2.206.gedb03e5


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