sh: CPU hotplug support.
This adds preliminary support for CPU hotplug for SH SMP systems.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c
index f6a9319..257de1f 100644
--- a/arch/sh/kernel/irq.c
+++ b/arch/sh/kernel/irq.c
@@ -12,6 +12,7 @@
#include <linux/kernel_stat.h>
#include <linux/seq_file.h>
#include <linux/ftrace.h>
+#include <linux/delay.h>
#include <asm/processor.h>
#include <asm/machvec.h>
#include <asm/uaccess.h>
@@ -292,3 +293,44 @@
return 0;
}
#endif
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu)
+{
+ printk(KERN_INFO "IRQ%u: moving from cpu%u to cpu%u\n",
+ irq, desc->node, cpu);
+
+ raw_spin_lock_irq(&desc->lock);
+ desc->chip->set_affinity(irq, cpumask_of(cpu));
+ raw_spin_unlock_irq(&desc->lock);
+}
+
+/*
+ * The CPU has been marked offline. Migrate IRQs off this CPU. If
+ * the affinity settings do not allow other CPUs, force them onto any
+ * available CPU.
+ */
+void migrate_irqs(void)
+{
+ struct irq_desc *desc;
+ unsigned int irq, cpu = smp_processor_id();
+
+ for_each_irq_desc(irq, desc) {
+ if (desc->node == cpu) {
+ unsigned int newcpu = cpumask_any_and(desc->affinity,
+ cpu_online_mask);
+ if (newcpu >= nr_cpu_ids) {
+ if (printk_ratelimit())
+ printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
+ irq, cpu);
+
+ cpumask_setall(desc->affinity);
+ newcpu = cpumask_any_and(desc->affinity,
+ cpu_online_mask);
+ }
+
+ route_irq(desc, irq, newcpu);
+ }
+ }
+}
+#endif