ARM: gic, local timers: use the request_percpu_irq() interface

This patch remove the hardcoded link between local timers and PPIs,
and convert the PPI users (TWD, MCT and MSM timers) to the new
*_percpu_irq interface. Also some collateral cleanup
(local_timer_ack() is gone, and the interrupt handler is strictly
private to each driver).

PPIs are now useable for more than just the local timers.

Additional testing by David Brown (msm8250 and msm8660) and
Shawn Guo (imx6q).

Cc: David Brown <davidb@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: David Brown <davidb@codeaurora.org>
Tested-by: David Brown <davidb@codeaurora.org>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

2 files changed, 46 insertions, 17 deletions

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 917ed2fa4e4c..a96c08cd6125 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -473,20 +473,6 @@ static void ipi_timer(void)
         irq_exit();
 }
 
-#ifdef CONFIG_LOCAL_TIMERS
-irqreturn_t percpu_timer_handler(int irq, void *dev_id)
-{
-        struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent);
-
-        if (local_timer_ack()) {
-                evt->event_handler(evt);
-                return IRQ_HANDLED;
-        }
-
-        return IRQ_NONE;
-}
-#endif
-
 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 static void smp_timer_broadcast(const struct cpumask *mask)
 {
@@ -537,7 +523,7 @@ static void percpu_timer_stop(void)
         unsigned int cpu = smp_processor_id();
         struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
 
-        evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
+        local_timer_stop(evt);
 }
 #endif
 
diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
index 01c186222f3b..a8a6682d6b52 100644
--- a/arch/arm/kernel/smp_twd.c
+++ b/arch/arm/kernel/smp_twd.c
@@ -19,6 +19,7 @@
 #include <linux/io.h>
 
 #include <asm/smp_twd.h>
+#include <asm/localtimer.h>
 #include <asm/hardware/gic.h>
 
 /* set up by the platform code */
@@ -26,6 +27,8 @@ void __iomem *twd_base;
 
 static unsigned long twd_timer_rate;
 
+static struct clock_event_device __percpu **twd_evt;
+
 static void twd_set_mode(enum clock_event_mode mode,
                         struct clock_event_device *clk)
 {
@@ -80,6 +83,12 @@ int twd_timer_ack(void)
         return 0;
 }
 
+void twd_timer_stop(struct clock_event_device *clk)
+{
+        twd_set_mode(CLOCK_EVT_MODE_UNUSED, clk);
+        disable_percpu_irq(clk->irq);
+}
+
 static void __cpuinit twd_calibrate_rate(void)
 {
         unsigned long count;
@@ -119,11 +128,43 @@ static void __cpuinit twd_calibrate_rate(void)
         }
 }
 
+static irqreturn_t twd_handler(int irq, void *dev_id)
+{
+        struct clock_event_device *evt = *(struct clock_event_device **)dev_id;
+
+        if (twd_timer_ack()) {
+                evt->event_handler(evt);
+                return IRQ_HANDLED;
+        }
+
+        return IRQ_NONE;
+}
+
 /*
  * Setup the local clock events for a CPU.
  */
 void __cpuinit twd_timer_setup(struct clock_event_device *clk)
 {
+        struct clock_event_device **this_cpu_clk;
+
+        if (!twd_evt) {
+                int err;
+
+                twd_evt = alloc_percpu(struct clock_event_device *);
+                if (!twd_evt) {
+                        pr_err("twd: can't allocate memory\n");
+                        return;
+                }
+
+                err = request_percpu_irq(clk->irq, twd_handler,
+                                         "twd", twd_evt);
+                if (err) {
+                        pr_err("twd: can't register interrupt %d (%d)\n",
+                               clk->irq, err);
+                        return;
+                }
+        }
+
         twd_calibrate_rate();
 
         clk->name = "local_timer";
@@ -137,8 +178,10 @@ void __cpuinit twd_timer_setup(struct clock_event_device *clk)
         clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk);
         clk->min_delta_ns = clockevent_delta2ns(0xf, clk);
 
+        this_cpu_clk = __this_cpu_ptr(twd_evt);
+        *this_cpu_clk = clk;
+
         clockevents_register_device(clk);
 
-        /* Make sure our local interrupt controller has this enabled */
-        gic_enable_ppi(clk->irq);
+        enable_percpu_irq(clk->irq, 0);
 }