x86: dtb: Add device tree support for HPET

Set hpet_address based on information provied form DTB
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Cc: sodaville@linutronix.de
Cc: devicetree-discuss@lists.ozlabs.org
Cc: Dirk Brandewie <dirk.brandewie@gmail.com>
LKML-Reference: <1298405266-1624-7-git-send-email-bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/devicetree.c

@@ -11,6 +11,7 @@
 #include <linux/of_platform.h>
 #include <linux/slab.h>
 
+#include <asm/hpet.h>
 #include <asm/irq_controller.h>
 #include <asm/apic.h>
 
@@ -98,6 +99,23 @@ void __init add_dtb(u64 data)
 	initial_dtb = data + offsetof(struct setup_data, data);
 }
 
+static void __init dtb_setup_hpet(void)
+{
+	struct device_node *dn;
+	struct resource r;
+	int ret;
+
+	dn = of_find_compatible_node(NULL, NULL, "intel,ce4100-hpet");
+	if (!dn)
+		return;
+	ret = of_address_to_resource(dn, 0, &r);
+	if (ret) {
+		WARN_ON(1);
+		return;
+	}
+	hpet_address = r.start;
+}
+
 static void __init dtb_lapic_setup(void)
 {
 #ifdef CONFIG_X86_LOCAL_APIC
@@ -197,5 +215,6 @@ void __init x86_dtb_get_config(unsigned int unused)
 	of_scan_flat_dt(early_init_dt_scan_root, NULL);
 
 	unflatten_device_tree();
+	dtb_setup_hpet();
 	dtb_apic_setup();
 }