irqchip/apple-aic: Parse FIQ affinities from device-tree

In order to be able to tell the core IRQ code about the affinity
of the PMU interrupt in later patches, parse the affinities kindly
provided in the device-tree.
Signed-off-by: Marc Zyngier <maz@kernel.org>

drivers/irqchip/irq-apple-aic.c

@@ -177,6 +177,9 @@ struct aic_irq_chip {
 	void __iomem *base;
 	struct irq_domain *hw_domain;
 	struct irq_domain *ipi_domain;
+	struct {
+		cpumask_t aff;
+	} *fiq_aff[AIC_NR_FIQ];
 	int nr_hw;
 };
 
@@ -793,12 +796,50 @@ static struct gic_kvm_info vgic_info __initdata = {
 	.no_hw_deactivation	= true,
 };
 
+static void build_fiq_affinity(struct aic_irq_chip *ic, struct device_node *aff)
+{
+	int i, n;
+	u32 fiq;
+
+	if (of_property_read_u32(aff, "apple,fiq-index", &fiq) ||
+	    WARN_ON(fiq >= AIC_NR_FIQ) || ic->fiq_aff[fiq])
+		return;
+
+	n = of_property_count_elems_of_size(aff, "cpus", sizeof(u32));
+	if (WARN_ON(n < 0))
+		return;
+
+	ic->fiq_aff[fiq] = kzalloc(sizeof(ic->fiq_aff[fiq]), GFP_KERNEL);
+	if (!ic->fiq_aff[fiq])
+		return;
+
+	for (i = 0; i < n; i++) {
+		struct device_node *cpu_node;
+		u32 cpu_phandle;
+		int cpu;
+
+		if (of_property_read_u32_index(aff, "cpus", i, &cpu_phandle))
+			continue;
+
+		cpu_node = of_find_node_by_phandle(cpu_phandle);
+		if (WARN_ON(!cpu_node))
+			continue;
+
+		cpu = of_cpu_node_to_id(cpu_node);
+		if (WARN_ON(cpu < 0))
+			continue;
+
+		cpumask_set_cpu(cpu, &ic->fiq_aff[fiq]->aff);
+	}
+}
+
 static int __init aic_of_ic_init(struct device_node *node, struct device_node *parent)
 {
 	int i;
 	void __iomem *regs;
 	u32 info;
 	struct aic_irq_chip *irqc;
+	struct device_node *affs;
 
 	regs = of_iomap(node, 0);
 	if (WARN_ON(!regs))
@@ -832,6 +873,14 @@ static int __init aic_of_ic_init(struct device_node *node, struct device_node *p
 		return -ENODEV;
 	}
 
+	affs = of_get_child_by_name(node, "affinities");
+	if (affs) {
+		struct device_node *chld;
+
+		for_each_child_of_node(affs, chld)
+			build_fiq_affinity(irqc, chld);
+	}
+
 	set_handle_irq(aic_handle_irq);
 	set_handle_fiq(aic_handle_fiq);