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clocksource: exynos_mct: Set IRQ affinity when the CPU goes online

PATCH Superseded Tomasz Figa 3 participants 4 messages Aug 26, 2013 – Sep 25, 2013

Subsystems (2)
Arm Samsung Exynos Clocksource, clockevent drivers
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Tomasz Figa

author
#0 lore raw

PATCH 1/1 clocksource: exynos_mct: Set IRQ affinity when the CPU goes online

Some variants of Exynos MCT, namely exynos4210-mct at the moment, use normal, shared interrupts for local timers. This means that each interrupt must have correct affinity set to fire only on CPU corresponding to given local timer.

However after recent conversion of clocksource drivers to not use the local timer API for local timer initialization any more, the point of time when local timers get initialized changed and irq_set_affinity() fails because the CPU is not marked as online yet.

This patch fixes this by moving the call to irq_set_affinity() to CPU_ONLINE notification, so the affinity is being set when the CPU goes online.

This fixes a problem with Exynos4210 failing to boot, present since commit
ee98d27df6 ARM: EXYNOS4: Divorce mct from local timer API
due to failing irq_set_affinity().

Signed-off-by Tomasz Figa <[email protected]>
Signed-off-by Kyungmin Park <[email protected]>
---
 drivers/clocksource/exynos_mct.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
drivers/clocksource/exynos_mct.c +9 -1
index 5b34768..62b0de6 100644
@@ -428,7 +428,6 @@ static int exynos4_local_timer_setup(struct clock_event_device *evt)
 				evt->irq);
 			return -EIO;
 		}
-		irq_set_affinity(evt->irq, cpumask_of(cpu));
 	} else {
 		enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0);
 	}

@@ -449,6 +448,7 @@ static int exynos4_mct_cpu_notify(struct notifier_block *self,
 					   unsigned long action, void *hcpu)
 {
 	struct mct_clock_event_device *mevt;
+	unsigned int cpu;
 
 	/*
 	 * Grab cpu pointer in each case to avoid spurious

@@ -459,6 +459,12 @@ static int exynos4_mct_cpu_notify(struct notifier_block *self,
 		mevt = this_cpu_ptr(&percpu_mct_tick);
 		exynos4_local_timer_setup(&mevt->evt);
 		break;
+	case CPU_ONLINE:
+		cpu = (unsigned long)hcpu;
+		if (mct_int_type == MCT_INT_SPI)
+			irq_set_affinity(mct_irqs[MCT_L0_IRQ + cpu],
+						cpumask_of(cpu));
+		break;
 	case CPU_DYING:
 		mevt = this_cpu_ptr(&percpu_mct_tick);
 		exynos4_local_timer_stop(&mevt->evt);

@@ -500,6 +506,8 @@ static void __init exynos4_timer_resources(struct device_node *np, void __iomem
 					 &percpu_mct_tick);
 		WARN(err, "MCT: can't request IRQ %d (%d)\n",
 		     mct_irqs[MCT_L0_IRQ], err);
+	} else {
+		irq_set_affinity(mct_irqs[MCT_L0_IRQ], cpumask_of(0));
 	}
 
 	err = register_cpu_notifier(&exynos4_mct_cpu_nb);
Signature · 1 line
1.8.3.2
#1 lore raw

PATCH 1/1 clocksource: exynos_mct: Set IRQ affinity when the CPU goes online

Quoted 14 lines · Tomasz Figa

Some variants of Exynos MCT, namely exynos4210-mct at the moment, use normal, shared interrupts for local timers. This means that each interrupt must have correct affinity set to fire only on CPU corresponding to given local timer.

However after recent conversion of clocksource drivers to not use the local timer API for local timer initialization any more, the point of time when local timers get initialized changed and irq_set_affinity() fails because the CPU is not marked as online yet.

This patch fixes this by moving the call to irq_set_affinity() to CPU_ONLINE notification, so the affinity is being set when the CPU goes online.

Quoted 7 lines

This fixes a problem with Exynos4210 failing to boot, present since commit
ee98d27df6 ARM: EXYNOS4: Divorce mct from local timer API
due to failing irq_set_affinity().

Signed-off-by Tomasz Figa <[email protected]>
Signed-off-by Kyungmin Park <[email protected]>

---

Looks good to me if you want to go this route.

Acked-by Stephen Boyd <[email protected]>
Signature · 2 lines
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation
#2 lore raw

PATCH 1/1 clocksource: exynos_mct: Set IRQ affinity when the CPU goes online

Quoted 22 lines · On Monday 26 of August 2013 16:09:41 Stephen Boyd wrote:
Quoted 21 lines · Tomasz Figa

Some variants of Exynos MCT, namely exynos4210-mct at the moment, use normal, shared interrupts for local timers. This means that each interrupt must have correct affinity set to fire only on CPU corresponding to given local timer.

However after recent conversion of clocksource drivers to not use the local timer API for local timer initialization any more, the point of time when local timers get initialized changed and irq_set_affinity() fails because the CPU is not marked as online yet.

This patch fixes this by moving the call to irq_set_affinity() to CPU_ONLINE notification, so the affinity is being set when the CPU goes
online.

This fixes a problem with Exynos4210 failing to boot, present since commit>
ee98d27df6 ARM: EXYNOS4: Divorce mct from local timer API

due to failing irq_set_affinity().

Quoted 7 lines
Quoted 3 lines
Signed-off-by Tomasz Figa <[email protected]>
Signed-off-by Kyungmin Park <[email protected]>

---

Looks good to me if you want to go this route.

Acked-by Stephen Boyd <[email protected]>

Thanks. After some testing this seems to work fine and I don't see any reason how the timer could be programmed to fire an interrupt before the CPU goes online, so it should be fine.

Anyway, we want this to be fixed for 3.12 for sure and since I don't really see any better solution we should take this one.

Best regards,
Tomasz

author
#3 lore raw

PATCH RESEND 1/1 clocksource: exynos_mct: Set IRQ affinity when the CPU goes online

In reply to Tomasz Figa

Some variants of Exynos MCT, namely exynos4210-mct at the moment, use normal, shared interrupts for local timers. This means that each interrupt must have correct affinity set to fire only on CPU corresponding to given local timer.

However after recent conversion of clocksource drivers to not use the local timer API for local timer initialization any more, the point of time when local timers get initialized changed and irq_set_affinity() fails because the CPU is not marked as online yet.

This patch fixes this by moving the call to irq_set_affinity() to CPU_ONLINE notification, so the affinity is being set when the CPU goes online.

This fixes a problem with Exynos4210 failing to boot, present since commit
ee98d27df6 ARM: EXYNOS4: Divorce mct from local timer API
due to failing irq_set_affinity().

Signed-off-by Tomasz Figa <[email protected]>
---
 drivers/clocksource/exynos_mct.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

Resending again, since my mail client previously freaked out and reset message format to HTML...

drivers/clocksource/exynos_mct.c +9 -1
index 5b34768..62b0de6 100644
@@ -428,7 +428,6 @@ static int exynos4_local_timer_setup(struct clock_event_device *evt)
 				evt->irq);
 			return -EIO;
 		}
-		irq_set_affinity(evt->irq, cpumask_of(cpu));
 	} else {
 		enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0);
 	}

@@ -449,6 +448,7 @@ static int exynos4_mct_cpu_notify(struct notifier_block *self,
 					   unsigned long action, void *hcpu)
 {
 	struct mct_clock_event_device *mevt;
+	unsigned int cpu;
 
 	/*
 	 * Grab cpu pointer in each case to avoid spurious

@@ -459,6 +459,12 @@ static int exynos4_mct_cpu_notify(struct notifier_block *self,
 		mevt = this_cpu_ptr(&percpu_mct_tick);
 		exynos4_local_timer_setup(&mevt->evt);
 		break;
+	case CPU_ONLINE:
+		cpu = (unsigned long)hcpu;
+		if (mct_int_type == MCT_INT_SPI)
+			irq_set_affinity(mct_irqs[MCT_L0_IRQ + cpu],
+						cpumask_of(cpu));
+		break;
 	case CPU_DYING:
 		mevt = this_cpu_ptr(&percpu_mct_tick);
 		exynos4_local_timer_stop(&mevt->evt);

@@ -500,6 +506,8 @@ static void __init exynos4_timer_resources(struct device_node *np, void __iomem
 					 &percpu_mct_tick);
 		WARN(err, "MCT: can't request IRQ %d (%d)\n",
 		     mct_irqs[MCT_L0_IRQ], err);
+	} else {
+		irq_set_affinity(mct_irqs[MCT_L0_IRQ], cpumask_of(0));
 	}
 
 	err = register_cpu_notifier(&exynos4_mct_cpu_nb);
Signature · 1 line
1.8.3.2