[PATCH] irqchip: gic: report GICD_IIDR

[Mark Rutland]

The GICD_IIDR register provides information about the implementer and
revision of the GIC distributor. In some cases this information is
useful for debugging, so log this when probing the GIC.

Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
---
 drivers/irqchip/irq-gic.c       | 4 ++++
 include/linux/irqchip/arm-gic.h | 1 +
 2 files changed, 5 insertions(+)

diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index 7b315e3..02c8bb4 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -959,6 +959,7 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start,
 	irq_hw_number_t hwirq_base;
 	struct gic_chip_data *gic;
 	int gic_irqs, irq_base, i;
+	unsigned long iidr;
 
 	BUG_ON(gic_nr >= MAX_GIC_NR);
 
@@ -996,6 +997,9 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start,
 		gic_set_base_accessor(gic, gic_get_common_base);
 	}
 
+	iidr = readl_relaxed(gic_data_dist_base(gic) + GIC_DIST_IIDR);
+	pr_info("GICD_IIDR reports 0x%08lx\n", (unsigned long)iidr);
+
 	/*
 	 * Initialize the CPU interface map to all CPUs.
 	 * It will be refined as each CPU probes its ID.
diff --git a/include/linux/irqchip/arm-gic.h b/include/linux/irqchip/arm-gic.h
index 36ec4ae..c29df66 100644
--- a/include/linux/irqchip/arm-gic.h
+++ b/include/linux/irqchip/arm-gic.h
@@ -29,6 +29,7 @@
 
 #define GIC_DIST_CTRL			0x000
 #define GIC_DIST_CTR			0x004
+#define GIC_DIST_IIDR			0x008
 #define GIC_DIST_IGROUP			0x080
 #define GIC_DIST_ENABLE_SET		0x100
 #define GIC_DIST_ENABLE_CLEAR		0x180
-- 
1.9.1

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