irqchip/gic: Add support to device tree based quirks

This patch adds support to device tree based quirks based on
device tree compatible string.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/irq-gic-common.c

@@ -36,6 +36,18 @@ void gic_set_kvm_info(const struct gic_kvm_info *info)
 	gic_kvm_info = info;
 }
 
+void gic_enable_of_quirks(const struct device_node *np,
+			  const struct gic_quirk *quirks, void *data)
+{
+	for (; quirks->desc; quirks++) {
+		if (!of_device_is_compatible(np, quirks->compatible))
+			continue;
+		if (quirks->init(data))
+			pr_info("GIC: enabling workaround for %s\n",
+				quirks->desc);
+	}
+}
+
 void gic_enable_quirks(u32 iidr, const struct gic_quirk *quirks,
 		void *data)
 {

drivers/irqchip/irq-gic-common.h

@@ -23,6 +23,7 @@
 
 struct gic_quirk {
 	const char *desc;
+	const char *compatible;
 	bool (*init)(void *data);
 	u32 iidr;
 	u32 mask;
@@ -35,6 +36,8 @@ void gic_dist_config(void __iomem *base, int gic_irqs,
 void gic_cpu_config(void __iomem *base, void (*sync_access)(void));
 void gic_enable_quirks(u32 iidr, const struct gic_quirk *quirks,
 		void *data);
+void gic_enable_of_quirks(const struct device_node *np,
+			  const struct gic_quirk *quirks, void *data);
 
 void gic_set_kvm_info(const struct gic_kvm_info *info);
 

drivers/irqchip/irq-gic-v3.c

@@ -1271,6 +1271,11 @@ static void __init gic_of_setup_kvm_info(struct device_node *node)
 	gic_set_kvm_info(&gic_v3_kvm_info);
 }
 
+static const struct gic_quirk gic_quirks[] = {
+	{
+	}
+};
+
 static int __init gic_of_init(struct device_node *node, struct device_node *parent)
 {
 	void __iomem *dist_base;
@@ -1318,6 +1323,8 @@ static int __init gic_of_init(struct device_node *node, struct device_node *pare
 	if (of_property_read_u64(node, "redistributor-stride", &redist_stride))
 		redist_stride = 0;
 
+	gic_enable_of_quirks(node, gic_quirks, &gic_data);
+
 	err = gic_init_bases(dist_base, rdist_regs, nr_redist_regions,
 			     redist_stride, &node->fwnode);
 	if (err)