[RFC PATCH 11/12] ARM: local timers: make MCT timer standalone
Marc Zyngier
marc.zyngier at arm.com
Tue Aug 9 06:46:53 EDT 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-exynos4/mct.c | 75 ++++++++++++++++++++++++++++++++----------
2 files changed, 58 insertions(+), 19 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 13cdba4..ef67b64 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1436,7 +1436,7 @@ config HOTPLUG_CPU
config LOCAL_TIMERS
bool "Use local timer interrupts"
- depends on SMP && !ARM_SMP_TWD && !ARCH_MSM
+ depends on SMP && !ARM_SMP_TWD && !ARCH_MSM && !EXYNOS4_MCT
default y
help
Enable support for local timers on SMP platforms, rather then the
diff --git a/arch/arm/mach-exynos4/mct.c b/arch/arm/mach-exynos4/mct.c
index 194fc6d..abe92cf 100644
--- a/arch/arm/mach-exynos4/mct.c
+++ b/arch/arm/mach-exynos4/mct.c
@@ -19,6 +19,7 @@
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/percpu.h>
+#include <linux/cpu.h>
#include <mach/map.h>
#include <mach/regs-mct.h>
@@ -28,11 +29,11 @@ static unsigned long clk_cnt_per_tick;
static unsigned long clk_rate;
struct mct_clock_event_device {
- struct clock_event_device *evt;
+ struct clock_event_device evt;
void __iomem *base;
};
-struct mct_clock_event_device mct_tick[2];
+static struct mct_clock_event_device __percpu *mct_tick;
static void exynos4_mct_write(unsigned int value, void *addr)
{
@@ -249,10 +250,10 @@ static void exynos4_clockevent_init(void)
setup_irq(IRQ_MCT_G0, &mct_comp_event_irq);
}
-#ifdef CONFIG_LOCAL_TIMERS
/* Clock event handling */
-static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
+static void exynos4_mct_tick_stop(void *data)
{
+ struct mct_clock_event_device *mevt = data;
unsigned long tmp;
unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
void __iomem *addr = mevt->base + MCT_L_TCON_OFFSET;
@@ -288,8 +289,9 @@ 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 = &mct_tick[smp_processor_id()];
+ struct mct_clock_event_device *mevt;
+ mevt = container_of(evt, struct mct_clock_event_device, evt);
exynos4_mct_tick_start(cycles, mevt);
return 0;
@@ -298,8 +300,9 @@ 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 = &mct_tick[smp_processor_id()];
+ struct mct_clock_event_device *mevt;
+ mevt = container_of(evt, struct mct_clock_event_device, evt);
exynos4_mct_tick_stop(mevt);
switch (mode) {
@@ -318,7 +321,7 @@ static inline void exynos4_tick_set_mode(enum clock_event_mode mode,
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;
/*
* This is for supporting oneshot mode.
@@ -348,17 +351,17 @@ 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(void *data)
{
+ struct mct_clock_event_device *mevt = data;
+ struct clock_event_device *evt = &mevt->evt;
unsigned int cpu = smp_processor_id();
- mct_tick[cpu].evt = evt;
-
if (cpu == 0) {
- mct_tick[cpu].base = EXYNOS4_MCT_L0_BASE;
+ mct_tick->base = EXYNOS4_MCT_L0_BASE;
evt->name = "mct_tick0";
} else {
- mct_tick[cpu].base = EXYNOS4_MCT_L1_BASE;
+ mct_tick->base = EXYNOS4_MCT_L1_BASE;
evt->name = "mct_tick1";
}
@@ -379,21 +382,56 @@ static void exynos4_mct_tick_init(struct clock_event_device *evt)
exynos4_mct_write(0x1, mct_tick[cpu].base + MCT_L_TCNTB_OFFSET);
if (cpu == 0) {
- mct_tick0_event_irq.dev_id = &mct_tick[cpu];
+ mct_tick0_event_irq.dev_id = mevt;
setup_irq(IRQ_MCT_L0, &mct_tick0_event_irq);
} else {
- mct_tick1_event_irq.dev_id = &mct_tick[cpu];
+ mct_tick1_event_irq.dev_id = mevt;
setup_irq(IRQ_MCT_L1, &mct_tick1_event_irq);
irq_set_affinity(IRQ_MCT_L1, cpumask_of(1));
}
}
-/* Setup the local clock events for a CPU */
-void __cpuinit local_timer_setup(struct clock_event_device *evt)
+static int __cpuinit exynos4_mct_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *data)
{
- exynos4_mct_tick_init(evt);
+ 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:
+ smp_call_function_single(cpu, exynos4_mct_tick_init, mevt, 1);
+ break;
+
+ case CPU_DOWN_PREPARE:
+ case CPU_DOWN_PREPARE_FROZEN:
+ smp_call_function_single(cpu, exynos4_mct_tick_stop, 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);
}
-#endif /* CONFIG_LOCAL_TIMERS */
static void __init exynos4_timer_resources(void)
{
@@ -408,6 +446,7 @@ static void __init exynos4_timer_init(void)
exynos4_timer_resources();
exynos4_clocksource_init();
exynos4_clockevent_init();
+ exynos4_mct_init();
}
struct sys_timer exynos4_timer = {
--
1.7.0.4
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