sh: Support CPU affinity masks for INTC controllers.

This hooks up the ->set_affinity() for the INTC controllers, which can be
done as just a simple copy of the cpumask. The enable/disable paths
already handle SMP register strides, so we just test the affinity mask in
these paths to determine which strides to skip over.

The early enable/disable path happens prior to the IRQs being registered,
so we have no affinity mask established at that point, in which case we
just default to CPU_MASK_ALL. This is left as it is to permit the force
enable/disable code to retain existing semantics.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

drivers/sh/intc.c

@@ -2,7 +2,7 @@
  * Shared interrupt handling code for IPR and INTC2 types of IRQs.
  *
  * Copyright (C) 2007, 2008 Magnus Damm
- * Copyright (C) 2009 Paul Mundt
+ * Copyright (C) 2009, 2010 Paul Mundt
  *
  * Based on intc2.c and ipr.c
  *
@@ -26,6 +26,7 @@
 #include <linux/list.h>
 #include <linux/topology.h>
 #include <linux/bitmap.h>
+#include <linux/cpumask.h>
 
 #define _INTC_MK(fn, mode, addr_e, addr_d, width, shift) \
 	((shift) | ((width) << 5) | ((fn) << 9) | ((mode) << 13) | \
@@ -234,6 +235,10 @@ static inline void _intc_enable(unsigned int irq, unsigned long handle)
 	unsigned int cpu;
 
 	for (cpu = 0; cpu < SMP_NR(d, _INTC_ADDR_E(handle)); cpu++) {
+#ifdef CONFIG_SMP
+		if (!cpumask_test_cpu(cpu, irq_to_desc(irq)->affinity))
+			continue;
+#endif
 		addr = INTC_REG(d, _INTC_ADDR_E(handle), cpu);
 		intc_enable_fns[_INTC_MODE(handle)](addr, handle, intc_reg_fns\
 						    [_INTC_FN(handle)], irq);
@@ -253,6 +258,10 @@ static void intc_disable(unsigned int irq)
 	unsigned int cpu;
 
 	for (cpu = 0; cpu < SMP_NR(d, _INTC_ADDR_D(handle)); cpu++) {
+#ifdef CONFIG_SMP
+		if (!cpumask_test_cpu(cpu, irq_to_desc(irq)->affinity))
+			continue;
+#endif
 		addr = INTC_REG(d, _INTC_ADDR_D(handle), cpu);
 		intc_disable_fns[_INTC_MODE(handle)](addr, handle,intc_reg_fns\
 						     [_INTC_FN(handle)], irq);
@@ -301,6 +310,23 @@ static int intc_set_wake(unsigned int irq, unsigned int on)
 	return 0; /* allow wakeup, but setup hardware in intc_suspend() */
 }
 
+#ifdef CONFIG_SMP
+/*
+ * This is held with the irq desc lock held, so we don't require any
+ * additional locking here at the intc desc level. The affinity mask is
+ * later tested in the enable/disable paths.
+ */
+static int intc_set_affinity(unsigned int irq, const struct cpumask *cpumask)
+{
+	if (!cpumask_intersects(cpumask, cpu_online_mask))
+		return -1;
+
+	cpumask_copy(irq_to_desc(irq)->affinity, cpumask);
+
+	return 0;
+}
+#endif
+
 static void intc_mask_ack(unsigned int irq)
 {
 	struct intc_desc_int *d = get_intc_desc(irq);
@@ -843,6 +869,9 @@ void __init register_intc_controller(struct intc_desc *desc)
 	d->chip.shutdown = intc_disable;
 	d->chip.set_type = intc_set_sense;
 	d->chip.set_wake = intc_set_wake;
+#ifdef CONFIG_SMP
+	d->chip.set_affinity = intc_set_affinity;
+#endif
 
 	if (hw->ack_regs) {
 		for (i = 0; i < hw->nr_ack_regs; i++)