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Commit 77c8d0d6 authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: clockevent: DT based probe 



 - timer frequency is derived from DT (no longer rely on top level
   DT "clock-frequency" probed early and exported by asm/clk.h)

 - TIMER0_IRQ need not be exported across arch code, confined to intc as
   it is property of same

 - Any failures in clockevent setup are considered pedantic and system
   panic()'s as there is no generic fallback (unlike clocksource where
   a jiffies based soft clocksource always exists)

Acked-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent 7ec9f34a

arch/arc/include/asm/irq.h

+0 −9
Original line number Diff line number Diff line
@@ -12,15 +12,6 @@ 
#define NR_CPU_IRQS	32  /* number of interrupt lines of ARC770 CPU */

#define NR_IRQS		128 /* allow some CPU external IRQ handling */



/* Platform Independent IRQs */

#ifdef CONFIG_ISA_ARCOMPACT

#define TIMER0_IRQ      3

#define TIMER1_IRQ      4

#else

#define TIMER0_IRQ      16

#define TIMER1_IRQ      17

#endif



#include <linux/interrupt.h>

#include <asm-generic/irq.h>

arch/arc/kernel/intc-compact.c

+2 −0
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ 
#include <linux/irqchip.h>

#include <asm/irq.h>



#define TIMER0_IRQ	3	/* Fixed by ISA */



/*

 * Early Hardware specific Interrupt setup

 * -Platform independent, needed for each CPU (not foldable into init_IRQ)

arch/arc/kernel/time.c

+43 −16
Original line number Diff line number Diff line
@@ -30,19 +30,15 @@ 
 */



#include <linux/interrupt.h>

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/time.h>

#include <linux/init.h>

#include <linux/clk.h>

#include <linux/clk-provider.h>

#include <linux/clocksource.h>

#include <linux/clockchips.h>

#include <linux/cpu.h>

#include <linux/of.h>

#include <linux/of_irq.h>

#include <asm/irq.h>

#include <asm/arcregs.h>

#include <asm/clk.h>

#include <asm/mach_desc.h>



#include <asm/mcip.h>
@@ -59,6 +55,30 @@ 


#define ARC_TIMER_MAX	0xFFFFFFFF



static unsigned long arc_timer_freq;



static int noinline arc_get_timer_clk(struct device_node *node)

{

	struct clk *clk;

	int ret;



	clk = of_clk_get(node, 0);

	if (IS_ERR(clk)) {

		pr_err("timer missing clk");

		return PTR_ERR(clk);

	}



	ret = clk_prepare_enable(clk);

	if (ret) {

		pr_err("Couldn't enable parent clk\n");

		return ret;

	}



	arc_timer_freq = clk_get_rate(clk);



	return 0;

}



/********** Clock Source Device *********/



#ifdef CONFIG_ARC_HAS_GFRC
@@ -182,7 +202,7 @@ static struct clocksource arc_counter = { 


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



static int arc_timer_irq = TIMER0_IRQ;

static int arc_timer_irq;



/*

 * Arm the timer to interrupt after @cycles
@@ -210,7 +230,7 @@ static int arc_clkevent_set_periodic(struct clock_event_device *dev) 
	 * At X Hz, 1 sec = 1000ms -> X cycles;

	 *		      10ms -> X / 100 cycles

	 */

	arc_timer_event_setup(arc_get_core_freq() / HZ);

	arc_timer_event_setup(arc_timer_freq / HZ);

	return 0;

}
@@ -253,7 +273,7 @@ static int arc_timer_cpu_notify(struct notifier_block *self, 


	switch (action & ~CPU_TASKS_FROZEN) {

	case CPU_STARTING:

		clockevents_config_and_register(evt, arc_get_core_freq(),

		clockevents_config_and_register(evt, arc_timer_freq,

						0, ULONG_MAX);

		enable_percpu_irq(arc_timer_irq, 0);

		break;
@@ -272,25 +292,35 @@ static struct notifier_block arc_timer_cpu_nb = { 
/*

 * clockevent setup for boot CPU

 */

static void __init arc_clockevent_setup(void)

static void __init arc_clockevent_setup(struct device_node *node)

{

	struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device);

	int ret;



	register_cpu_notifier(&arc_timer_cpu_nb);



	arc_timer_irq = irq_of_parse_and_map(node, 0);

	if (arc_timer_irq <= 0)

		panic("clockevent: missing irq");



	ret = arc_get_timer_clk(node);

	if (ret)

		panic("clockevent: missing clk");



	evt->irq = arc_timer_irq;

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

	clockevents_config_and_register(evt, arc_get_core_freq(),

	clockevents_config_and_register(evt, arc_timer_freq,

					0, ARC_TIMER_MAX);



	/* 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");

		panic("clockevent: unable to request irq\n");



	enable_percpu_irq(arc_timer_irq, 0);

}

CLOCKSOURCE_OF_DECLARE(arc_clkevt, "snps,arc-timer", arc_clockevent_setup);



/*

 * Called from start_kernel() - boot CPU only
@@ -299,7 +329,6 @@ static void __init arc_clockevent_setup(void) 
 * -Also sets up any global state needed for timer subsystem:

 *    - for "counting" timer, registers a clocksource, usable across CPUs

 *      (provided that underlying counter h/w is synchronized across cores)

 *    - for "event" timer, sets up TIMER0 IRQ (as that is platform agnostic)

 */

void __init time_init(void)

{
@@ -315,7 +344,5 @@ void __init time_init(void) 
		 * CLK upto 4.29 GHz can be safely represented in 32 bits

		 * because Max 32 bit number is 4,294,967,295

		 */

		clocksource_register_hz(&arc_counter, arc_get_core_freq());



	arc_clockevent_setup();

		clocksource_register_hz(&arc_counter, arc_timer_freq);

}