Add device tree support to the arm_smp_twd driver.
The DT bindings for the TWD are defined as such:
- one timer node per CPU, using corresponding PPI
interrupt controller
- provides both timer and watchdog interrupt
Tested on RealView PB11MPCore and VExpress.
Signed-off-by: Marc Zyngier <marc.zyng...@arm.com>
---
Documentation/devicetree/bindings/arm/twd.txt | 54 ++++++++++++++
drivers/clocksource/arm_smp_twd.c | 92 +++++++++++++++++++++---
2 files changed, 134 insertions(+), 12 deletions(-)
create mode 100644 Documentation/devicetree/bindings/arm/twd.txt
diff --git a/Documentation/devicetree/bindings/arm/twd.txt
b/Documentation/devicetree/bindings/arm/twd.txt
new file mode 100644
index 0000000..3823a81
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/twd.txt
@@ -0,0 +1,54 @@
+* ARM Timer Watchdog
+
+ARM SMP cores are often associated with a TWD providing a per-cpu timer
+and a per-cpu watchdog. Usually wired to the PPI interface of a GIC.
+
+Main node properties:
+
+- compatible : "arm,smp-twd", "localtimer"
+- reg : register mapping for the registers.
+- #address-cells : <1>
+- #size-cells : <0>
+
+Timer sub nodes (one per CPU)
+
+- interrupt-parent : phandle to the corresponding gic-ppi.
+- interrupts : <IRQtimer IRQwatchdog> (usually <29 30>)
+- reg : index of the CPU this timer is connected to.
+
+Example (ARM RealView PB11-MPCore):
+
+localtimer@1f000600 {
+ compatible = "arm,smp-twd", "localtimer";
+ reg = <0x1f000600 0x100>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ /*
+ * One timer per CPU, bound to the corresponding
+ * PPI interface.
+ */
+ timer@0 {
+ interrupt-parent = <&gic0ppi0>;
+ interrupts = <29 30>;
+ reg = <0>;
+ };
+
+ timer@1 {
+ interrupt-parent = <&gic0ppi1>;
+ interrupts = <29 30>;
+ reg = <1>;
+ };
+
+ timer@2 {
+ interrupt-parent = <&gic0ppi2>;
+ interrupts = <29 30>;
+ reg = <2>;
+ };
+
+ timer@3 {
+ interrupt-parent = <&gic0ppi3>;
+ interrupts = <29 30>;
+ reg = <3>;
+ };
+};
diff --git a/drivers/clocksource/arm_smp_twd.c
b/drivers/clocksource/arm_smp_twd.c
index 65f4669..586acad 100644
--- a/drivers/clocksource/arm_smp_twd.c
+++ b/drivers/clocksource/arm_smp_twd.c
@@ -19,6 +19,9 @@
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
+#include <linux/of_platform.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
#include <linux/clk.h>
#include <linux/cpufreq.h>
#include <linux/err.h>
@@ -37,11 +40,11 @@
#define TWD_TIMER_CONTROL_IT_ENABLE (1 << 2)
static void __iomem *twd_base;
-static int twd_ppi;
static struct clk *twd_clk;
static unsigned long twd_timer_rate;
static DEFINE_PER_CPU(bool, irq_reqd);
+static DEFINE_PER_CPU(int, twd_irq);
static struct clock_event_device __percpu *twd_evt;
static void twd_set_mode(enum clock_event_mode mode,
@@ -223,7 +226,7 @@ static void __cpuinit twd_setup(void *data)
clk->rating = 450;
clk->set_mode = twd_set_mode;
clk->set_next_event = twd_set_next_event;
- clk->irq = gic_ppi_to_vppi(twd_ppi);
+ clk->irq = __get_cpu_var(twd_irq);
clk->cpumask = cpumask_of(smp_processor_id());
pr_debug("Configuring %s on cpu #%d\n", clk->name, smp_processor_id());
@@ -290,31 +293,90 @@ static struct notifier_block __cpuinitdata twd_cpu_nb = {
.notifier_call = twd_cpu_notify,
};
-static int twd_probe(struct platform_device *pdev)
+#ifdef CONFIG_OF
+static struct device_node *twd_get_timer_node(struct device_node *twd_np,
+ struct device_node *child,
+ int *timer_nr)
+{
+ child = of_get_next_child(twd_np, child);
+ if (child) {
+ const __be32 *reg;
+ reg = of_get_property(child, "reg", NULL);
+ if (!reg)
+ *timer_nr = -1;
+ else
+ *timer_nr = be32_to_cpu(*reg);
+ }
+
+ return child;
+}
+
+static int __devinit twd_of_probe_irq(struct platform_device *pdev)
+{
+ struct device_node *timer = NULL;
+ int timer_nr;
+
+ if (!pdev->dev.of_node)
+ return -1;
+
+ while((timer = twd_get_timer_node(pdev->dev.of_node,
+ timer, &timer_nr))) {
+ if (timer_nr < 0 || timer_nr >= NR_CPUS) {
+ dev_info(&pdev->dev, "Unknown timer id %d\n", timer_nr);
+ continue;
+ }
+
+ per_cpu(twd_irq, timer_nr) = irq_of_parse_and_map(timer, 0);
+ pr_info("%s IRQ%d", timer->full_name, per_cpu(twd_irq,
timer_nr));
+ }
+
+ return 0;
+}
+#else
+static int __devinit twd_of_probe_irq(struct platform_device *pdev)
+{
+ return -1;
+}
+#endif
+
+static int __devinit twd_probe(struct platform_device *pdev)
{
struct resource *mem;
struct clock_event_device *clk;
- int irq;
if (twd_base)
return -EBUSY;
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- irq = platform_get_irq(pdev, 0);
- if (!mem || irq < 0)
+ if (!mem)
return -EINVAL;
+ twd_base = ioremap(mem->start, resource_size(mem));
+
+ if (!twd_base)
+ return -ENOMEM;
+
+ if (twd_of_probe_irq(pdev)) {
+ int irq;
+ int i;
- twd_base = ioremap(mem->start, resource_size(mem));
- twd_evt = alloc_percpu(struct clock_event_device);
- if (!twd_base || !twd_evt) {
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ iounmap(twd_base);
+ return -EINVAL;
+ }
+
+ for (i = 0; i < NR_CPUS; i++)
+ per_cpu(twd_irq, i) = gic_ppi_to_cpu_vppi(irq, i);
+ }
+
+ twd_evt = alloc_percpu(struct clock_event_device);
+ if (!twd_evt) {
iounmap(twd_base);
twd_base = NULL;
free_percpu(twd_evt);
return -ENOMEM;
}
- twd_ppi = irq;
-
/* Immediately configure the timer on the boot CPU */
clk = per_cpu_ptr(twd_evt, smp_processor_id());
twd_setup(clk);
@@ -329,11 +391,17 @@ static int twd_remove(struct platform_device *pdev)
return -EBUSY;
}
+static const struct of_device_id twd_of_ids[] = {
+ { .compatible = "arm,smp-twd" },
+ { },
+};
+
static struct platform_driver twd_driver = {
.probe = twd_probe,
.remove = __devexit_p(twd_remove),
.driver = {
- .name = "arm_smp_twd",
+ .name = "arm_smp_twd",
+ .of_match_table = twd_of_ids,
},
};
--
1.7.0.4
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