[PATCH v2 13/15] ARM: local timers: make MCT timer standalone
Marc Zyngier
marc.zyngier at arm.com
Thu Dec 22 12:27:43 EST 2011
Following the same pattern used for smp_twd, allow the MCT timers
to be built in standalone, without relying on the CONFIG_LOCAL_TIMER
infrastructure and use a CPU notifier block to stop or start
the timer on the right CPU.
Cc: Kukjin Kim <kgene.kim at samsung.com>
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
arch/arm/Kconfig | 2 +-
arch/arm/mach-exynos/mct.c | 85 ++++++++++++++++++++++++++++++-------------
2 files changed, 60 insertions(+), 27 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index c3732bb..f5563c5 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1564,7 +1564,7 @@ config HOTPLUG_CPU
config LOCAL_TIMERS
bool "Use local timer interrupts"
- depends on SMP && !ARM_SMP_TWD
+ depends on SMP && !ARM_SMP_TWD && !EXYNOS4_MCT
default y
help
Enable support for local timers on SMP platforms, rather then the
diff --git a/arch/arm/mach-exynos/mct.c b/arch/arm/mach-exynos/mct.c
index 85b5527..2f1ab9f 100644
--- a/arch/arm/mach-exynos/mct.c
+++ b/arch/arm/mach-exynos/mct.c
@@ -19,6 +19,7 @@
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/percpu.h>
+#include <linux/cpu.h>
#include <asm/hardware/gic.h>
@@ -39,7 +40,7 @@ static unsigned long clk_rate;
static unsigned int mct_int_type;
struct mct_clock_event_device {
- struct clock_event_device *evt;
+ struct clock_event_device evt;
void __iomem *base;
char name[10];
};
@@ -261,9 +262,7 @@ static void exynos4_clockevent_init(void)
setup_irq(IRQ_MCT_G0, &mct_comp_event_irq);
}
-#ifdef CONFIG_LOCAL_TIMERS
-
-static DEFINE_PER_CPU(struct mct_clock_event_device, percpu_mct_tick);
+static struct mct_clock_event_device __percpu *mct_tick;
/* Clock event handling */
static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
@@ -303,8 +302,9 @@ static void exynos4_mct_tick_start(unsigned long cycles,
static int exynos4_tick_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
- struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
+ struct mct_clock_event_device *mevt;
+ mevt = container_of(evt, struct mct_clock_event_device, evt);
exynos4_mct_tick_start(cycles, mevt);
return 0;
@@ -313,8 +313,9 @@ static int exynos4_tick_set_next_event(unsigned long cycles,
static inline void exynos4_tick_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
- struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
+ struct mct_clock_event_device *mevt;
+ mevt = container_of(evt, struct mct_clock_event_device, evt);
exynos4_mct_tick_stop(mevt);
switch (mode) {
@@ -332,7 +333,7 @@ static inline void exynos4_tick_set_mode(enum clock_event_mode mode,
static int exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
{
- struct clock_event_device *evt = mevt->evt;
+ struct clock_event_device *evt = &mevt->evt;
/*
* This is for supporting oneshot mode.
@@ -354,7 +355,7 @@ static int exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
{
struct mct_clock_event_device *mevt = dev_id;
- struct clock_event_device *evt = mevt->evt;
+ struct clock_event_device *evt = &mevt->evt;
exynos4_mct_tick_clear(mevt);
@@ -375,14 +376,11 @@ static struct irqaction mct_tick1_event_irq = {
.handler = exynos4_mct_tick_isr,
};
-static void exynos4_mct_tick_init(struct clock_event_device *evt)
+static void __cpuinit exynos4_mct_tick_init(struct mct_clock_event_device *mevt)
{
- struct mct_clock_event_device *mevt;
+ struct clock_event_device *evt = &mevt->evt;
unsigned int cpu = smp_processor_id();
- mevt = this_cpu_ptr(&percpu_mct_tick);
- mevt->evt = evt;
-
mevt->base = EXYNOS4_MCT_L_BASE(cpu);
sprintf(mevt->name, "mct_tick%d", cpu);
@@ -419,17 +417,12 @@ static void exynos4_mct_tick_init(struct clock_event_device *evt)
}
}
-/* Setup the local clock events for a CPU */
-int __cpuinit local_timer_setup(struct clock_event_device *evt)
-{
- exynos4_mct_tick_init(evt);
-
- return 0;
-}
-
-void local_timer_stop(struct clock_event_device *evt)
+void exynos4_mct_tick_halt(void *data)
{
+ struct mct_clock_event_device *mevt = data;
+ struct clock_event_device *evt = &mevt->evt;
unsigned int cpu = smp_processor_id();
+
evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
if (mct_int_type == MCT_INT_SPI)
if (cpu == 0)
@@ -439,7 +432,48 @@ void local_timer_stop(struct clock_event_device *evt)
else
disable_percpu_irq(IRQ_MCT_LOCALTIMER);
}
-#endif /* CONFIG_LOCAL_TIMERS */
+
+static int __cpuinit exynos4_mct_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *data)
+{
+ int cpu = (int)data;
+ struct mct_clock_event_device *mevt = per_cpu_ptr(mct_tick, cpu);
+
+ switch (action) {
+ case CPU_STARTING:
+ case CPU_STARTING_FROZEN:
+ exynos4_mct_tick_init(mevt);
+ break;
+
+ case CPU_DOWN_PREPARE:
+ case CPU_DOWN_PREPARE_FROZEN:
+ smp_call_function_single(cpu, exynos4_mct_tick_halt, mevt, 1);
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata exynos4_mct_cpu_nb = {
+ .notifier_call = exynos4_mct_cpu_notify,
+};
+
+static void __init exynos4_mct_init(void)
+{
+ struct mct_clock_event_device *mevt;
+
+ mct_tick = alloc_percpu(struct mct_clock_event_device);
+ if (!mct_tick) {
+ pr_err("exynos4_mct_init: can't allocate memory\n");
+ return;
+ }
+
+ /* Immediately configure the timer on the boot CPU */
+ mevt = per_cpu_ptr(mct_tick, smp_processor_id());
+ exynos4_mct_tick_init(mevt);
+
+ register_cpu_notifier(&exynos4_mct_cpu_nb);
+}
static void __init exynos4_timer_resources(void)
{
@@ -448,17 +482,15 @@ static void __init exynos4_timer_resources(void)
clk_rate = clk_get_rate(mct_clk);
-#ifdef CONFIG_LOCAL_TIMERS
if (mct_int_type == MCT_INT_PPI) {
int err;
err = request_percpu_irq(IRQ_MCT_LOCALTIMER,
exynos4_mct_tick_isr, "MCT",
- &percpu_mct_tick);
+ mct_tick);
WARN(err, "MCT: can't request IRQ %d (%d)\n",
IRQ_MCT_LOCALTIMER, err);
}
-#endif /* CONFIG_LOCAL_TIMERS */
}
static void __init exynos4_timer_init(void)
@@ -471,6 +503,7 @@ static void __init exynos4_timer_init(void)
exynos4_timer_resources();
exynos4_clocksource_init();
exynos4_clockevent_init();
+ exynos4_mct_init();
}
struct sys_timer exynos4_timer = {
--
1.7.7.1
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