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>

arch/arm/common/gic.c

@@ -35,7 +35,6 @@
 #include <asm/irq.h>
 #include <asm/mach/irq.h>
 #include <asm/hardware/gic.h>
-#include <asm/localtimer.h>
 
 static DEFINE_SPINLOCK(irq_controller_lock);
 
@@ -259,32 +258,6 @@ void __init gic_cascade_irq(unsigned int gic_nr, unsigned int irq)
 	irq_set_chained_handler(irq, gic_handle_cascade_irq);
 }
 
-#ifdef CONFIG_LOCAL_TIMERS
-#define gic_ppi_handler		percpu_timer_handler
-#else
-static irqreturn_t gic_ppi_handler(int irq, void *dev_id)
-{
-	return IRQ_NONE;
-}
-#endif
-
-#define PPI_IRQACT(nr)						\
-	{							\
-		.handler	= gic_ppi_handler,		\
-		.flags		= IRQF_PERCPU | IRQF_TIMER,	\
-		.irq		= nr,				\
-		.name		= "PPI-" # nr,			\
-	}
-
-static struct irqaction ppi_irqaction_template[16] __initdata = {
-	PPI_IRQACT(0),  PPI_IRQACT(1),  PPI_IRQACT(2),  PPI_IRQACT(3),
-	PPI_IRQACT(4),  PPI_IRQACT(5),  PPI_IRQACT(6),  PPI_IRQACT(7),
-	PPI_IRQACT(8),  PPI_IRQACT(9),  PPI_IRQACT(10), PPI_IRQACT(11),
-	PPI_IRQACT(12), PPI_IRQACT(13), PPI_IRQACT(14), PPI_IRQACT(15),
-};
-
-static struct irqaction *ppi_irqaction;
-
 static void __init gic_dist_init(struct gic_chip_data *gic,
 	unsigned int irq_start)
 {
@@ -325,16 +298,6 @@ static void __init gic_dist_init(struct gic_chip_data *gic,
 			BUG();
 
 		ppi_base = gic->irq_offset + 32 - nrppis;
-
-		ppi_irqaction = kmemdup(&ppi_irqaction_template[16 - nrppis],
-					sizeof(*ppi_irqaction) * nrppis,
-					GFP_KERNEL);
-
-		if (nrppis && !ppi_irqaction) {
-			pr_err("GIC: Can't allocate PPI memory");
-			nrppis = 0;
-			ppi_base = 0;
-		}
 	}
 
 	pr_info("Configuring GIC with %d sources (%d PPIs)\n",
@@ -377,17 +340,12 @@ static void __init gic_dist_init(struct gic_chip_data *gic,
 	 */
 	for (i = 0; i < nrppis; i++) {
 		int ppi = i + ppi_base;
-		int err;
 
 		irq_set_percpu_devid(ppi);
 		irq_set_chip_and_handler(ppi, &gic_chip,
 					 handle_percpu_devid_irq);
 		irq_set_chip_data(ppi, gic);
 		set_irq_flags(ppi, IRQF_VALID | IRQF_NOAUTOEN);
-
-		err = setup_percpu_irq(ppi, &ppi_irqaction[i]);
-		if (err)
-			pr_err("GIC: can't setup PPI%d (%d)\n", ppi, err);
 	}
 
 	for (i = irq_start + nrppis; i < irq_limit; i++) {
@@ -448,16 +406,6 @@ void __cpuinit gic_secondary_init(unsigned int gic_nr)
 	gic_cpu_init(&gic_data[gic_nr]);
 }
 
-void __cpuinit gic_enable_ppi(unsigned int irq)
-{
-	unsigned long flags;
-
-	local_irq_save(flags);
-	irq_set_status_flags(irq, IRQ_NOPROBE);
-	gic_unmask_irq(irq_get_irq_data(irq));
-	local_irq_restore(flags);
-}
-
 #ifdef CONFIG_SMP
 void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
 {

arch/arm/include/asm/hardware/gic.h

@@ -40,7 +40,6 @@ void gic_init(unsigned int, unsigned int, void __iomem *, void __iomem *);
 void gic_secondary_init(unsigned int);
 void gic_cascade_irq(unsigned int gic_nr, unsigned int irq);
 void gic_raise_softirq(const struct cpumask *mask, unsigned int irq);
-void gic_enable_ppi(unsigned int);
 
 struct gic_chip_data {
 	unsigned int irq_offset;

arch/arm/include/asm/localtimer.h

@@ -19,26 +19,20 @@ struct clock_event_device;
  */
 void percpu_timer_setup(void);
 
-/*
- * Per-cpu timer IRQ handler
- */
-irqreturn_t percpu_timer_handler(int irq, void *dev_id);
-
 #ifdef CONFIG_LOCAL_TIMERS
 
 #ifdef CONFIG_HAVE_ARM_TWD
 
 #include "smp_twd.h"
 
-#define local_timer_ack()	twd_timer_ack()
+#define local_timer_stop(c)	twd_timer_stop((c))
 
 #else
 
 /*
- * Platform provides this to acknowledge a local timer IRQ.
- * Returns true if the local timer IRQ is to be processed.
+ * Stop the local timer
  */
-int local_timer_ack(void);
+void local_timer_stop(struct clock_event_device *);
 
 #endif
 
@@ -53,6 +47,10 @@ static inline int local_timer_setup(struct clock_event_device *evt)
 {
 	return -ENXIO;
 }
+
+static inline void local_timer_stop(struct clock_event_device *evt)
+{
+}
 #endif
 
 #endif

arch/arm/include/asm/smp_twd.h

@@ -22,7 +22,7 @@ struct clock_event_device;
 
 extern void __iomem *twd_base;
 
-int twd_timer_ack(void);
 void twd_timer_setup(struct clock_event_device *);
+void twd_timer_stop(struct clock_event_device *);
 
 #endif

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
 

arch/arm/kernel/smp_twd.c

@@ -19,13 +19,16 @@
 #include <linux/io.h>
 
 #include <asm/smp_twd.h>
+#include <asm/localtimer.h>
 #include <asm/hardware/gic.h>
 
 /* set up by the platform code */
 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);
 }

arch/arm/mach-exynos4/mct.c

@@ -380,9 +380,11 @@ static void exynos4_mct_tick_init(struct clock_event_device *evt)
 
 	if (cpu == 0) {
 		mct_tick0_event_irq.dev_id = &mct_tick[cpu];
+		evt->irq = IRQ_MCT_L0;
 		setup_irq(IRQ_MCT_L0, &mct_tick0_event_irq);
 	} else {
 		mct_tick1_event_irq.dev_id = &mct_tick[cpu];
+		evt->irq = IRQ_MCT_L1;
 		setup_irq(IRQ_MCT_L1, &mct_tick1_event_irq);
 		irq_set_affinity(IRQ_MCT_L1, cpumask_of(1));
 	}
@@ -394,9 +396,10 @@ void __cpuinit local_timer_setup(struct clock_event_device *evt)
 	exynos4_mct_tick_init(evt);
 }
 
-int local_timer_ack(void)
+void local_timer_stop(struct clock_event_device *evt)
 {
-	return 0;
+	evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
+	disable_irq(evt->irq);
 }
 
 #endif /* CONFIG_LOCAL_TIMERS */