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Commit d8e03643 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

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: default avatarRob Herring <rob.herring@calxeda.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 81e46f7b

Documentation/devicetree/bindings/arm/twd.txt

0 → 100644
+48 −0
Original line number Original line Diff line number Diff line 
* 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>;

	};

arch/arm/include/asm/smp_twd.h

+8 −0
Original line number Original line Diff line number Diff line
@@ -40,4 +40,12 @@ struct twd_local_timer name __initdata = { \ 




int twd_local_timer_register(struct twd_local_timer *);

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
 
#endif

arch/arm/kernel/smp_twd.c

+64 −13
Original line number Original line Diff line number Diff line
@@ -20,6 +20,8 @@ 
#include <linux/clockchips.h>

#include <linux/clockchips.h>

#include <linux/irq.h>

#include <linux/irq.h>

#include <linux/io.h>

#include <linux/io.h>

#include <linux/of_irq.h>

#include <linux/of_address.h>





#include <asm/smp_twd.h>

#include <asm/smp_twd.h>

#include <asm/localtimer.h>

#include <asm/localtimer.h>
@@ -284,37 +286,86 @@ static struct local_timer_ops twd_lt_ops __cpuinitdata = { 
	.stop	= twd_timer_stop,

	.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;

	int err;





	if (twd_base || twd_evt)

		return -EBUSY;



	twd_ppi	= tlt->res[1].start;



	twd_evt = alloc_percpu(struct clock_event_device *);

	twd_evt = alloc_percpu(struct clock_event_device *);

	twd_base = ioremap(tlt->res[0].start, resource_size(&tlt->res[0]));

	if (!twd_evt) {

	if (!twd_base || !twd_evt) {

		err = -ENOMEM;

		err = -ENOMEM;

		goto out;

		goto out_free;

	}

	}





	err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt);

	err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt);

	if (err) {

	if (err) {

		pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, 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);

	err = local_timer_register(&twd_lt_ops);

	if (err)

	if (err)

		goto out;

		goto out_irq;





	return 0;

	return 0;





out:

out_irq:

	free_percpu_irq(twd_ppi, twd_evt);

out_free:

	iounmap(twd_base);

	iounmap(twd_base);

	twd_base = NULL;

	free_percpu(twd_evt);

	free_percpu(twd_evt);

	twd_base = twd_evt = NULL;



	return err;

	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