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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: Noam Camus <noamc@ezchip.com>
[vgupta: broken off from a bigger patch]
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Noam Camus 2016-01-01 15:48:49 +05:30 committed by Vineet Gupta
parent 0eeb3dfe4b
commit eec3c58efa
3 changed files with 43 additions and 26 deletions
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1
arch/arc/include/asm/irq.h
View File

@ -25,6 +25,5 @@
#include <asm-generic/irq.h>
extern void arc_init_IRQ(void);
void arc_local_timer_setup(void);
#endif

2
arch/arc/kernel/smp.c
View File

@ -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);

66
arch/arc/kernel/time.c
View File

@ -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;
}
/*
* Setup the local event timer for @cpu
*/
void arc_local_timer_setup()
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);
int cpu = smp_processor_id();
int irq = TIMER0_IRQ;
evt->cpumask = cpumask_of(cpu);
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,
};
/*
* clockevent setup for boot CPU
*/
static void __init arc_clockevent_setup(void)
{
struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device);
int ret;
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;
/* 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 (ret)
pr_err("Unable to register interrupt\n");
rc = request_percpu_irq(irq, timer_irq_handler,
"Timer0 (per-cpu-tick)", evt);
if (rc)
panic("Percpu IRQ request failed for TIMER\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();
}