Commit eec3c58e authored by Noam Camus's avatar Noam Camus Committed by Vineet Gupta
Browse files

ARC: clockevent: switch to cpu notifier for clockevent setup 



ARC Timers so far have been handled as "legacy" w/o explicit description
in DT. This poses challenge for newer platforms wanting to use them.
This series will eventually help move timers over to DT.

This patch does a small change of using a CPU notifier to set clockevent
on non-boot CPUs. So explicit setup is done only on boot CPU (which will
later be done by DT)

Signed-off-by: default avatarNoam Camus <noamc@ezchip.com>
[vgupta: broken off from a bigger patch]
Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent 0eeb3dfe

arch/arc/include/asm/irq.h

+0 −1
Original line number Diff line number Diff line
@@ -25,6 +25,5 @@ 
#include <asm-generic/irq.h>



extern void arc_init_IRQ(void);

void arc_local_timer_setup(void);



#endif

arch/arc/kernel/smp.c

+0 −2
Original line number Diff line number Diff line
@@ -138,8 +138,6 @@ void start_kernel_secondary(void) 
	if (machine_desc->init_per_cpu)

		machine_desc->init_per_cpu(cpu);



	arc_local_timer_setup();



	local_irq_enable();

	preempt_disable();

	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);

arch/arc/kernel/time.c

+41 −21
Original line number Diff line number Diff line
@@ -29,17 +29,14 @@ 
 * which however is currently broken

 */



#include <linux/spinlock.h>

#include <linux/interrupt.h>

#include <linux/module.h>

#include <linux/sched.h>

#include <linux/kernel.h>

#include <linux/time.h>

#include <linux/init.h>

#include <linux/timex.h>

#include <linux/profile.h>

#include <linux/clocksource.h>

#include <linux/clockchips.h>

#include <linux/cpu.h>

#include <asm/irq.h>

#include <asm/arcregs.h>

#include <asm/clk.h>
@@ -183,6 +180,8 @@ static struct clocksource arc_counter = { 


/********** Clock Event Device *********/



static int arc_timer_irq = TIMER0_IRQ;



/*

 * Arm the timer to interrupt after @cycles

 * The distinction for oneshot/periodic is done in arc_event_timer_ack() below
@@ -218,7 +217,6 @@ static DEFINE_PER_CPU(struct clock_event_device, arc_clockevent_device) = { 
	.features		= CLOCK_EVT_FEAT_ONESHOT |

				  CLOCK_EVT_FEAT_PERIODIC,

	.rating			= 300,

	.irq			= TIMER0_IRQ,	/* hardwired, no need for resources */

	.set_next_event		= arc_clkevent_set_next_event,

	.set_state_periodic	= arc_clkevent_set_periodic,

};
@@ -244,29 +242,52 @@ static irqreturn_t timer_irq_handler(int irq, void *dev_id) 
	return IRQ_HANDLED;

}



static int arc_timer_cpu_notify(struct notifier_block *self,

				unsigned long action, void *hcpu)

{

	struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device);



	evt->cpumask = cpumask_of(smp_processor_id());



	switch (action & ~CPU_TASKS_FROZEN) {

	case CPU_STARTING:

		clockevents_config_and_register(evt, arc_get_core_freq(),

						0, ULONG_MAX);

		enable_percpu_irq(arc_timer_irq, 0);

		break;

	case CPU_DYING:

		disable_percpu_irq(arc_timer_irq);

		break;

	}



	return NOTIFY_OK;

}



static struct notifier_block arc_timer_cpu_nb = {

	.notifier_call = arc_timer_cpu_notify,

};



/*

 * Setup the local event timer for @cpu

 * clockevent setup for boot CPU

 */

void arc_local_timer_setup()

static void __init arc_clockevent_setup(void)

{

	struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device);

	int cpu = smp_processor_id();

	int irq = TIMER0_IRQ;

	int ret;



	evt->cpumask = cpumask_of(cpu);

	register_cpu_notifier(&arc_timer_cpu_nb);



	evt->cpumask = cpumask_of(smp_processor_id());

	clockevents_config_and_register(evt, arc_get_core_freq(),

					0, ARC_TIMER_MAX);



	if (!cpu) {

		int rc;



		rc = request_percpu_irq(irq, timer_irq_handler,

	/* Needs apriori irq_set_percpu_devid() done in intc map function */

	ret = request_percpu_irq(arc_timer_irq, timer_irq_handler,

				 "Timer0 (per-cpu-tick)", evt);

		if (rc)

			panic("Percpu IRQ request failed for TIMER\n");

	}

	if (ret)

		pr_err("Unable to register interrupt\n");



	enable_percpu_irq(irq, 0);

	enable_percpu_irq(arc_timer_irq, 0);

}



/*
@@ -291,6 +312,5 @@ void __init time_init(void) 
		 */

		clocksource_register_hz(&arc_counter, arc_get_core_freq());



	/* sets up the periodic event timer */

	arc_local_timer_setup();

	arc_clockevent_setup();

}

CRA Git | Maintained and supported by SUSTech CRA and CCSE