ARM: smp_twd: add device tree support

Add bindings to support DT discovery of the ARM Timer Watchdog
(aka TWD). Only the timer side is converted by this patch.

Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

arch/arm/kernel/smp_twd.c

@@ -20,6 +20,8 @@
 #include <linux/clockchips.h>
 #include <linux/irq.h>
 #include <linux/io.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
 
 #include <asm/smp_twd.h>
 #include <asm/localtimer.h>
@@ -284,37 +286,86 @@ static struct local_timer_ops twd_lt_ops __cpuinitdata = {
 	.stop	= twd_timer_stop,
 };
 
-int __init twd_local_timer_register(struct twd_local_timer *tlt)
+static int __init twd_local_timer_common_register(void)
 {
 	int err;
 
-	if (twd_base || twd_evt)
-		return -EBUSY;
-
-	twd_ppi	= tlt->res[1].start;
-
 	twd_evt = alloc_percpu(struct clock_event_device *);
-	twd_base = ioremap(tlt->res[0].start, resource_size(&tlt->res[0]));
-	if (!twd_base || !twd_evt) {
+	if (!twd_evt) {
 		err = -ENOMEM;
-		goto out;
+		goto out_free;
 	}
 
 	err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt);
 	if (err) {
 		pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, err);
-		goto out;
+		goto out_free;
 	}
 
 	err = local_timer_register(&twd_lt_ops);
 	if (err)
-		goto out;
+		goto out_irq;
 
 	return 0;
 
-out:
+out_irq:
+	free_percpu_irq(twd_ppi, twd_evt);
+out_free:
 	iounmap(twd_base);
+	twd_base = NULL;
 	free_percpu(twd_evt);
-	twd_base = twd_evt = NULL;
+
 	return err;
 }
+
+int __init twd_local_timer_register(struct twd_local_timer *tlt)
+{
+	if (twd_base || twd_evt)
+		return -EBUSY;
+
+	twd_ppi	= tlt->res[1].start;
+
+	twd_base = ioremap(tlt->res[0].start, resource_size(&tlt->res[0]));
+	if (!twd_base)
+		return -ENOMEM;
+
+	return twd_local_timer_common_register();
+}
+
+#ifdef CONFIG_OF
+const static struct of_device_id twd_of_match[] __initconst = {
+	{ .compatible = "arm,cortex-a9-twd-timer",	},
+	{ .compatible = "arm,cortex-a5-twd-timer",	},
+	{ .compatible = "arm,arm11mp-twd-timer",	},
+	{ },
+};
+
+void __init twd_local_timer_of_register(void)
+{
+	struct device_node *np;
+	int err;
+
+	np = of_find_matching_node(NULL, twd_of_match);
+	if (!np) {
+		err = -ENODEV;
+		goto out;
+	}
+
+	twd_ppi = irq_of_parse_and_map(np, 0);
+	if (!twd_ppi) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	twd_base = of_iomap(np, 0);
+	if (!twd_base) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	err = twd_local_timer_common_register();
+
+out:
+	WARN(err, "twd_local_timer_of_register failed (%d)\n", err);
+}
+#endif