Commit a8655e83 authored by Catalin Marinas's avatar Catalin Marinas Committed by Russell King
Browse files

[ARM] 4814/1: RealView: Add broadcasting clockevents support for ARM11MPCore 



This patch adds dummy local timers for each CPU so that the board clock
device is used to broadcast events to the other CPUs. The patch also
adds the declaration for the dummy_timer_setup function (the equivalent
of local_timer_setup when CONFIG_LOCAL_TIMERS is not set).

Due to the way clockevents work, the dummy timer on the first CPU has to
be registered before the board timer.

Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 3e459990

arch/arm/Kconfig

+5 −0
Original line number Diff line number Diff line
@@ -33,6 +33,11 @@ config GENERIC_CLOCKEVENTS 
	bool

	default n



config GENERIC_CLOCKEVENTS_BROADCAST

	bool

	depends on GENERIC_CLOCKEVENTS

	default y if SMP && !LOCAL_TIMERS



config MMU

	bool

	default y

arch/arm/kernel/smp.c

+5 −5
Original line number Diff line number Diff line
@@ -290,6 +290,11 @@ asmlinkage void __cpuinit secondary_start_kernel(void) 
	local_irq_enable();

	local_fiq_enable();



	/*

	 * Setup local timer for this CPU.

	 */

	local_timer_setup(cpu);



	calibrate_delay();



	smp_store_cpu_info(cpu);
@@ -299,11 +304,6 @@ asmlinkage void __cpuinit secondary_start_kernel(void) 
	 */

	cpu_set(cpu, cpu_online_map);



	/*

	 * Setup local timer for this CPU.

	 */

	local_timer_setup(cpu);



	/*

	 * OK, it's off to the idle thread for us

	 */

arch/arm/mach-realview/Makefile

+1 −2
Original line number Diff line number Diff line
@@ -4,6 +4,5 @@ 


obj-y					:= core.o clock.o

obj-$(CONFIG_MACH_REALVIEW_EB)		+= realview_eb.o

obj-$(CONFIG_SMP)			+= platsmp.o headsmp.o

obj-$(CONFIG_SMP)			+= platsmp.o headsmp.o localtimer.o

obj-$(CONFIG_HOTPLUG_CPU)		+= hotplug.o
 
obj-$(CONFIG_LOCAL_TIMERS)		+= localtimer.o

arch/arm/mach-realview/core.c

+9 −1
Original line number Diff line number Diff line
@@ -596,12 +596,20 @@ static void __init realview_clocksource_init(void) 
}



/*

 * Set up timer interrupt, and return the current time in seconds.

 * Set up the clock source and clock events devices

 */

static void __init realview_timer_init(void)

{

	u32 val;



#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST

	/*

	 * The dummy clock device has to be registered before the main device

	 * so that the latter will broadcast the clock events

	 */

	local_timer_setup(smp_processor_id());

#endif



	/* 

	 * set clock frequency: 

	 *	REALVIEW_REFCLK is 32KHz

arch/arm/mach-realview/localtimer.c

+39 −0
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ 
#include <linux/device.h>

#include <linux/smp.h>

#include <linux/jiffies.h>

#include <linux/percpu.h>

#include <linux/clockchips.h>



#include <asm/mach/time.h>

#include <asm/hardware/arm_twd.h>
@@ -25,6 +27,20 @@ 
#define TWD_BASE(cpu)	(__io_address(REALVIEW_TWD_BASE) + \

			 ((cpu) * REALVIEW_TWD_SIZE))



static DEFINE_PER_CPU(struct clock_event_device, local_clockevent);



/*

 * Used on SMP for either the local timer or IPI_TIMER

 */

void local_timer_interrupt(void)

{

	struct clock_event_device *clk = &__get_cpu_var(local_clockevent);



	clk->event_handler(clk);

}



#ifdef CONFIG_LOCAL_TIMERS



static unsigned long mpcore_timer_rate;



/*
@@ -127,3 +143,26 @@ void __cpuexit local_timer_stop(unsigned int cpu) 
{

	__raw_writel(0, TWD_BASE(cpu) + TWD_TIMER_CONTROL);

}



#else	/* CONFIG_LOCAL_TIMERS */



static void dummy_timer_set_mode(enum clock_event_mode mode,

				 struct clock_event_device *clk)

{

}



void __cpuinit local_timer_setup(unsigned int cpu)

{

	struct clock_event_device *clk = &per_cpu(local_clockevent, cpu);



	clk->name		= "dummy_timer";

	clk->features		= CLOCK_EVT_FEAT_DUMMY;

	clk->rating		= 200;

	clk->set_mode		= dummy_timer_set_mode;

	clk->broadcast		= smp_timer_broadcast;

	clk->cpumask		= cpumask_of_cpu(cpu);



	clockevents_register_device(clk);

}



#endif	/* !CONFIG_LOCAL_TIMERS */