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>

diff --git a/Documentation/devicetree/bindings/arm/twd.txt b/Documentation/devicetree/bindings/arm/twd.txt
new file mode 100644 (file)
index 0000000..75b8610
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/twd.txt
@@ -0,0 +1,48 @@
+* ARM Timer Watchdog
+
+ARM 11MP, Cortex-A5 and Cortex-A9 are often associated with a per-core
+Timer-Watchdog (aka TWD), which provides both a per-cpu local timer
+and watchdog.
+
+The TWD is usually attached to a GIC to deliver its two per-processor
+interrupts.
+
+** Timer node required properties:
+
+- compatible : Should be one of:
+       "arm,cortex-a9-twd-timer"
+       "arm,cortex-a5-twd-timer"
+       "arm,arm11mp-twd-timer"
+
+- interrupts : One interrupt to each core
+
+- reg : Specify the base address and the size of the TWD timer
+       register window.
+
+Example:
+
+       twd-timer@2c000600 {
+               compatible = "arm,arm11mp-twd-timer"";
+               reg = <0x2c000600 0x20>;
+               interrupts = <1 13 0xf01>;
+       };
+
+** Watchdog node properties:
+
+- compatible : Should be one of:
+       "arm,cortex-a9-twd-wdt"
+       "arm,cortex-a5-twd-wdt"
+       "arm,arm11mp-twd-wdt"
+
+- interrupts : One interrupt to each core
+
+- reg : Specify the base address and the size of the TWD watchdog
+       register window.
+
+Example:
+
+       twd-watchdog@2c000620 {
+               compatible = "arm,arm11mp-twd-wdt";
+               reg = <0x2c000620 0x20>;
+               interrupts = <1 14 0xf01>;
+       };

diff --git a/arch/arm/include/asm/smp_twd.h b/arch/arm/include/asm/smp_twd.h
index 16c89b7..8047e6e 100644 (file)
--- a/arch/arm/include/asm/smp_twd.h
+++ b/arch/arm/include/asm/smp_twd.h
@@ -40,4 +40,12 @@ struct twd_local_timer name __initdata = {   \
 
 int twd_local_timer_register(struct twd_local_timer *);
 
+#ifdef CONFIG_HAVE_ARM_TWD
+void twd_local_timer_of_register(void);
+#else
+static inline void twd_local_timer_of_register(void)
+{
+}
+#endif
+
 #endif

diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
index 18c55f1..761826c 100644 (file)
--- a/arch/arm/kernel/smp_twd.c
+++ b/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