[PATCH v1 02/18] ARM: local timers: Add runtime registration interface
Marc Zyngier
marc.zyngier at arm.com
Fri Jun 3 10:57:17 EDT 2011
Current local timer code suffers from being resolved at link time,
preventing from having multiple implementations supported by the
same kernel.
Introduce a registration interface that the platform can call at
runtime. smp_twd.c now returns a set of operations that percpu_timer.c
can call.
Acked-by: Catalin Marinas <catalin.marinas at arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
arch/arm/include/asm/localtimer.h | 48 +++++++++++++++-----------
arch/arm/include/asm/smp_twd.h | 27 +++++++++++++--
arch/arm/kernel/percpu_timer.c | 67 +++++++++++++++++++++++++++++++++++--
arch/arm/kernel/smp_twd.c | 29 +++++++++++++++-
4 files changed, 142 insertions(+), 29 deletions(-)
diff --git a/arch/arm/include/asm/localtimer.h b/arch/arm/include/asm/localtimer.h
index b3fd6ea..f95e527 100644
--- a/arch/arm/include/asm/localtimer.h
+++ b/arch/arm/include/asm/localtimer.h
@@ -29,39 +29,47 @@ irqreturn_t percpu_timer_handler(int irq, void *dev_id);
*/
void percpu_timer_run(void);
-#ifdef CONFIG_LOCAL_TIMERS
-
-#ifdef CONFIG_HAVE_ARM_TWD
-
-#include "smp_twd.h"
-
-#define local_timer_ack() twd_timer_ack()
-
-#else
-
-/*
- * Platform provides this to acknowledge a local timer IRQ.
- * Returns true if the local timer IRQ is to be processed.
- */
-int local_timer_ack(void);
-
-#endif
/*
* Stop a per-cpu timer
*/
void percpu_timer_stop(void);
+struct local_timer_ops {
+ void (*const pre_setup)(struct clock_event_device *clk);
+ int (*plat_setup)(struct clock_event_device *clk);
+ void (*plat_teardown)(struct clock_event_device *clk);
+ void (*const setup)(struct clock_event_device *clk);
+ int (*const ack)(void);
+};
+
+#ifdef CONFIG_LOCAL_TIMERS
/*
* Setup a local timer interrupt for a CPU.
*/
int local_timer_setup(struct clock_event_device *);
+/*
+ * Register a local timer.
+ */
+void percpu_timer_register(struct local_timer_ops *);
#else
-
-static inline int local_timer_setup(struct clock_event_device *evt)
+static inline void percpu_timer_register(void *dummy)
{
- return -ENXIO;
}
#endif
+static inline int percpu_timer_register_setup(struct local_timer_ops *ops,
+ int (*plat_setup)(struct clock_event_device *),
+ void (*plat_teardown)(struct clock_event_device *))
+{
+ if (ops) {
+ ops->plat_setup = plat_setup;
+ ops->plat_teardown = plat_teardown;
+ percpu_timer_register(ops);
+ return 0;
+ }
+
+ return -ENODEV;
+}
+
#endif
diff --git a/arch/arm/include/asm/smp_twd.h b/arch/arm/include/asm/smp_twd.h
index fed9981..4096736 100644
--- a/arch/arm/include/asm/smp_twd.h
+++ b/arch/arm/include/asm/smp_twd.h
@@ -1,6 +1,8 @@
#ifndef __ASMARM_SMP_TWD_H
#define __ASMARM_SMP_TWD_H
+#include <linux/clockchips.h>
+
#define TWD_TIMER_LOAD 0x00
#define TWD_TIMER_COUNTER 0x04
#define TWD_TIMER_CONTROL 0x08
@@ -18,11 +20,28 @@
#define TWD_TIMER_CONTROL_PERIODIC (1 << 1)
#define TWD_TIMER_CONTROL_IT_ENABLE (1 << 2)
-struct clock_event_device;
-
extern void __iomem *twd_base;
-int twd_timer_ack(void);
-void twd_timer_setup(struct clock_event_device *);
+#ifdef CONFIG_HAVE_ARM_TWD
+struct local_timer_ops *local_timer_get_twd_ops(void);
+int twd_timer_register_setup(int (*setup)(struct clock_event_device *));
+#else
+static inline struct local_timer_ops *local_timer_get_twd_ops(void)
+{
+ return NULL;
+}
+
+static inline int twd_timer_register_setup(int (*setup)(struct clock_event_device *))
+{
+ return -ENODEV;
+}
+#endif
+
+/*
+ * Dummy function, to be removed once there is no in-tree user anymore.
+ */
+static inline void twd_timer_setup(void *dummy)
+{
+}
#endif
diff --git a/arch/arm/kernel/percpu_timer.c b/arch/arm/kernel/percpu_timer.c
index 4b6e230..94315f5 100644
--- a/arch/arm/kernel/percpu_timer.c
+++ b/arch/arm/kernel/percpu_timer.c
@@ -9,10 +9,13 @@
* published by the Free Software Foundation.
*/
+#include <linux/irq.h>
+#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/clockchips.h>
#include <asm/localtimer.h>
+#include <asm/smp_twd.h>
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
static void broadcast_timer_set_mode(enum clock_event_mode mode,
@@ -38,6 +41,44 @@ static void broadcast_timer_setup(struct clock_event_device *evt)
clockevents_register_device(evt);
}
+static struct local_timer_ops broadcast_timer_ops = {
+ .setup = broadcast_timer_setup,
+};
+
+static struct local_timer_ops *timer_ops;
+
+int __attribute__ ((weak)) local_timer_setup(struct clock_event_device *evt)
+{
+ return -ENXIO;
+}
+
+void percpu_timer_register(struct local_timer_ops *ops)
+{
+ timer_ops = ops;
+}
+
+/*
+ * local_timer_ack: checks for a local timer interrupt.
+ *
+ * If a local timer interrupt has occurred, acknowledge and return 1.
+ * Otherwise, return 0.
+ *
+ * This can be overloaded by platform code that doesn't provide its
+ * timer in timer_fns way (msm at the moment). Once all platforms have
+ * migrated, the weak alias can be removed.
+ * If no ack() function has been registered, consider the acknowledgement
+ * to be done.
+ */
+static int percpu_timer_ack(void)
+{
+ if (timer_ops->ack)
+ return timer_ops->ack();
+
+ return 1;
+}
+
+int local_timer_ack(void) __attribute__ ((weak, alias("percpu_timer_ack")));
+
/*
* Timer (local or broadcast) support
*/
@@ -63,14 +104,32 @@ void percpu_timer_run(void)
void __cpuinit percpu_timer_setup(void)
{
+ int ret = 0;
unsigned int cpu = smp_processor_id();
struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
+ /*
+ * All this can go away once we've migrated all users to
+ * properly register the timer they use, and broadcast can
+ * become the fallback.
+ */
+ if (!timer_ops)
+ timer_ops = local_timer_get_twd_ops();
+ if (!timer_ops)
+ timer_ops = &broadcast_timer_ops;
+ if (!timer_ops->plat_setup)
+ timer_ops->plat_setup = local_timer_setup;
+
evt->cpumask = cpumask_of(cpu);
- evt->broadcast = smp_timer_broadcast;
- if (local_timer_setup(evt))
- broadcast_timer_setup(evt);
+ if (timer_ops->pre_setup)
+ timer_ops->pre_setup(evt);
+ if (timer_ops->plat_setup)
+ ret = timer_ops->plat_setup(evt);
+ if (ret) /* Fallback to broadcast */
+ timer_ops = &broadcast_timer_ops;
+ if (timer_ops->setup)
+ timer_ops->setup(evt);
}
#ifdef CONFIG_HOTPLUG_CPU
@@ -85,5 +144,7 @@ void percpu_timer_stop(void)
struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
+ if (timer_ops->plat_teardown)
+ timer_ops->plat_teardown(evt);
}
#endif
diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
index aa99656..91296df 100644
--- a/arch/arm/kernel/smp_twd.c
+++ b/arch/arm/kernel/smp_twd.c
@@ -18,6 +18,7 @@
#include <linux/interrupt.h>
#include <linux/io.h>
+#include <asm/localtimer.h>
#include <asm/smp_twd.h>
#include <asm/localtimer.h>
#include <asm/hardware/gic.h>
@@ -74,7 +75,7 @@ static int twd_set_next_event(unsigned long evt,
* If a local timer interrupt has occurred, acknowledge and return 1.
* Otherwise, return 0.
*/
-int twd_timer_ack(void)
+static int twd_timer_ack(void)
{
if (__raw_readl(twd_base + TWD_TIMER_INTSTAT)) {
__raw_writel(1, twd_base + TWD_TIMER_INTSTAT);
@@ -126,7 +127,7 @@ static void __cpuinit twd_calibrate_rate(void)
/*
* Setup the local clock events for a CPU.
*/
-void __cpuinit twd_timer_setup(struct clock_event_device *clk)
+static void __cpuinit twd_setup(struct clock_event_device *clk)
{
int err;
bool *reqd;
@@ -161,3 +162,27 @@ void __cpuinit twd_timer_setup(struct clock_event_device *clk)
clockevents_register_device(clk);
}
+
+static struct local_timer_ops twd_timer_ops = {
+ .setup = twd_setup,
+ .ack = twd_timer_ack,
+};
+
+struct local_timer_ops *local_timer_get_twd_ops(void)
+{
+ if (!twd_base) {
+ pr_warn("TWD base address not set\n");
+ return NULL;
+ }
+
+ return &twd_timer_ops;
+}
+
+int __init twd_timer_register_setup(int (*setup)(struct clock_event_device *))
+{
+ if (!twd_base)
+ return -ENODEV;
+
+ percpu_timer_register_setup(&twd_timer_ops, setup, NULL);
+ return 0;
+}
--
1.7.0.4
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