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Commit 0075242b authored by Marc Zyngier's avatar Marc Zyngier
Browse files

ARM: architected timers: add DT support 



Add runtime DT support and documentation for the Cortex A7/A15
architected timers.

Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 3f61c80e

Documentation/devicetree/bindings/arm/arch_timer.txt

0 → 100644
+27 −0
Original line number Diff line number Diff line 
* ARM architected timer



ARM Cortex-A7 and Cortex-A15 have a per-core architected timer, which

provides per-cpu timers.



The timer is attached to a GIC to deliver its per-processor interrupts.



** Timer node properties:



- compatible : Should at least contain "arm,armv7-timer".



- interrupts : Interrupt list for secure, non-secure, virtual and

  hypervisor timers, in that order.



- clock-frequency : The frequency of the main counter, in Hz. Optional.



Example:



	timer {

		compatible = "arm,cortex-a15-timer",

			     "arm,armv7-timer";

		interrupts = <1 13 0xf08>,

			     <1 14 0xf08>,

			     <1 11 0xf08>,

			     <1 10 0xf08>;

		clock-frequency = <100000000>;

	};

arch/arm/include/asm/arch_timer.h

+6 −0
Original line number Diff line number Diff line
@@ -10,12 +10,18 @@ struct arch_timer { 
#ifdef CONFIG_ARM_ARCH_TIMER

int arch_timer_register(struct arch_timer *);

int arch_timer_sched_clock_init(void);

int arch_timer_of_register(void);

#else

static inline int arch_timer_register(struct arch_timer *at)

{

	return -ENXIO;

}



static inline int arch_timer_of_register(void)

{

	return -ENXIO;

}



static inline int arch_timer_sched_clock_init(void)

{

	return -ENXIO;

arch/arm/kernel/arch_timer.c

+46 −7
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/jiffies.h>

#include <linux/clockchips.h>

#include <linux/interrupt.h>

#include <linux/of_irq.h>

#include <linux/io.h>



#include <asm/cputype.h>
@@ -245,13 +246,10 @@ static struct local_timer_ops arch_timer_ops __cpuinitdata = { 
	.stop	= arch_timer_stop,

};



int __init arch_timer_register(struct arch_timer *at)

static int __init arch_timer_common_register(void)

{

	int err;



	if (at->res[0].start <= 0 || !(at->res[0].flags & IORESOURCE_IRQ))

		return -EINVAL;



	err = arch_timer_available();

	if (err)

		return err;
@@ -262,7 +260,6 @@ int __init arch_timer_register(struct arch_timer *at) 


	clocksource_register_hz(&clocksource_counter, arch_timer_rate);



	arch_timer_ppi = at->res[0].start;

	err = request_percpu_irq(arch_timer_ppi, arch_timer_handler,

				 "arch_timer", arch_timer_evt);

	if (err) {
@@ -271,8 +268,7 @@ int __init arch_timer_register(struct arch_timer *at) 
		goto out_free;

	}



	if (at->res[1].start > 0 || (at->res[1].flags & IORESOURCE_IRQ)) {

		arch_timer_ppi2 = at->res[1].start;

	if (arch_timer_ppi2) {

		err = request_percpu_irq(arch_timer_ppi2, arch_timer_handler,

					 "arch_timer", arch_timer_evt);

		if (err) {
@@ -300,6 +296,49 @@ int __init arch_timer_register(struct arch_timer *at) 
	return err;

}



int __init arch_timer_register(struct arch_timer *at)

{

	if (at->res[0].start <= 0 || !(at->res[0].flags & IORESOURCE_IRQ))

		return -EINVAL;



	arch_timer_ppi = at->res[0].start;



	if (at->res[1].start > 0 || (at->res[1].flags & IORESOURCE_IRQ))

		arch_timer_ppi2 = at->res[1].start;



	return arch_timer_common_register();

}



#ifdef CONFIG_OF

static const struct of_device_id arch_timer_of_match[] __initconst = {

	{ .compatible	= "arm,armv7-timer",	},

	{},

};



int __init arch_timer_of_register(void)

{

	struct device_node *np;

	u32 freq;



	np = of_find_matching_node(NULL, arch_timer_of_match);

	if (!np) {

		pr_err("arch_timer: can't find DT node\n");

		return -ENODEV;

	}



	/* Try to determine the frequency from the device tree or CNTFRQ */

	if (!of_property_read_u32(np, "clock-frequency", &freq))

		arch_timer_rate = freq;



	arch_timer_ppi = irq_of_parse_and_map(np, 0);

	arch_timer_ppi2 = irq_of_parse_and_map(np, 1);

	pr_info("arch_timer: found %s irqs %d %d\n",

		np->name, arch_timer_ppi, arch_timer_ppi2);



	return arch_timer_common_register();

}

#endif



int __init arch_timer_sched_clock_init(void)

{

	int err;