Commit 12ad1000 authored by Mark Rutland's avatar Mark Rutland Committed by Thomas Gleixner
Browse files

clockevents: Add generic timer broadcast function 



Currently, the timer broadcast mechanism is defined by a function
pointer on struct clock_event_device. As the fundamental mechanism for
broadcast is architecture-specific, this means that clock_event_device
drivers cannot be shared across multiple architectures.

This patch adds an (optional) architecture-specific function for timer
tick broadcast, allowing drivers which may require broadcast
functionality to be shared across multiple architectures.

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Reviewed-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: nico@linaro.org
Cc: Will.Deacon@arm.com
Cc: Marc.Zyngier@arm.com
Cc: john.stultz@linaro.org
Link: http://lkml.kernel.org/r/1358183124-28461-3-git-send-email-mark.rutland@arm.com


Tested-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: default avatarStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 12572dbb

include/linux/clockchips.h

+5 −0
Original line number Diff line number Diff line
@@ -162,6 +162,11 @@ extern void clockevents_suspend(void); 
extern void clockevents_resume(void);



#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST

#ifdef CONFIG_ARCH_HAS_TICK_BROADCAST

extern void tick_broadcast(const struct cpumask *mask);

#else

#define tick_broadcast	NULL

#endif

extern int tick_receive_broadcast(void);

#endif

kernel/time/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -38,6 +38,10 @@ config GENERIC_CLOCKEVENTS_BUILD 
	default y

	depends on GENERIC_CLOCKEVENTS



# Architecture can handle broadcast in a driver-agnostic way

config ARCH_HAS_TICK_BROADCAST

	bool



# Clockevents broadcasting infrastructure

config GENERIC_CLOCKEVENTS_BROADCAST

	bool

kernel/time/tick-broadcast.c

+13 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/percpu.h>

#include <linux/profile.h>

#include <linux/sched.h>

#include <linux/smp.h>



#include "tick-internal.h"
@@ -86,6 +87,11 @@ int tick_is_broadcast_device(struct clock_event_device *dev) 
	return (dev && tick_broadcast_device.evtdev == dev);

}



static void err_broadcast(const struct cpumask *mask)

{

	pr_crit_once("Failed to broadcast timer tick. Some CPUs may be unresponsive.\n");

}



/*

 * Check, if the device is disfunctional and a place holder, which

 * needs to be handled by the broadcast device.
@@ -105,6 +111,13 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) 
	 */

	if (!tick_device_is_functional(dev)) {

		dev->event_handler = tick_handle_periodic;

		if (!dev->broadcast)

			dev->broadcast = tick_broadcast;

		if (!dev->broadcast) {

			pr_warn_once("%s depends on broadcast, but no broadcast function available\n",

				     dev->name);

			dev->broadcast = err_broadcast;

		}

		cpumask_set_cpu(cpu, tick_get_broadcast_mask());

		tick_broadcast_start_periodic(tick_broadcast_device.evtdev);

		ret = 1;

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