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Commit 1ba1cefc authored by Mark Rutland's avatar Mark Rutland
Browse files

arm: arch_timer: divorce from local_timer api 



Currently, the arch_timer driver is tied to the arm port, as it relies
on code in arch/arm/smp.c to setup and teardown timers as cores are
hotplugged on and off. The timer is registered through an arm-specific
registration mechanism, preventing sharing the driver with the arm64
port.

This patch moves the driver to using a cpu notifier instead, making it
easier to port.

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Acked-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
parent 45801042

arch/arm/kernel/arch_timer.c

+29 −23
Original line number Diff line number Diff line
@@ -21,7 +21,6 @@ 
#include <linux/io.h>



#include <asm/delay.h>

#include <asm/localtimer.h>

#include <asm/arch_timer.h>

#include <asm/sched_clock.h>
@@ -37,7 +36,7 @@ enum ppi_nr { 


static int arch_timer_ppi[MAX_TIMER_PPI];



static struct clock_event_device __percpu **arch_timer_evt;

static struct clock_event_device __percpu *arch_timer_evt;

static struct delay_timer arch_delay_timer;



static bool arch_timer_use_virtual = true;
@@ -63,14 +62,14 @@ static irqreturn_t inline timer_handler(const int access, 


static irqreturn_t arch_timer_handler_virt(int irq, void *dev_id)

{

	struct clock_event_device *evt = *(struct clock_event_device **)dev_id;

	struct clock_event_device *evt = dev_id;



	return timer_handler(ARCH_TIMER_VIRT_ACCESS, evt);

}



static irqreturn_t arch_timer_handler_phys(int irq, void *dev_id)

{

	struct clock_event_device *evt = *(struct clock_event_device **)dev_id;

	struct clock_event_device *evt = dev_id;



	return timer_handler(ARCH_TIMER_PHYS_ACCESS, evt);

}
@@ -141,13 +140,13 @@ static int __cpuinit arch_timer_setup(struct clock_event_device *clk) 
		clk->set_next_event = arch_timer_set_next_event_phys;

	}



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



	clk->set_mode(CLOCK_EVT_MODE_SHUTDOWN, NULL);



	clockevents_config_and_register(clk, arch_timer_rate,

					0xf, 0x7fffffff);



	*__this_cpu_ptr(arch_timer_evt) = clk;



	if (arch_timer_use_virtual)

		enable_percpu_irq(arch_timer_ppi[VIRT_PPI], 0);

	else {
@@ -251,12 +250,26 @@ static void __cpuinit arch_timer_stop(struct clock_event_device *clk) 
	clk->set_mode(CLOCK_EVT_MODE_UNUSED, clk);

}



static struct local_timer_ops arch_timer_ops __cpuinitdata = {

	.setup	= arch_timer_setup,

	.stop	= arch_timer_stop,

};

static int __cpuinit arch_timer_cpu_notify(struct notifier_block *self,

					   unsigned long action, void *hcpu)

{

	struct clock_event_device *evt = this_cpu_ptr(arch_timer_evt);



	switch (action & ~CPU_TASKS_FROZEN) {

	case CPU_STARTING:

		arch_timer_setup(evt);

		break;

	case CPU_DYING:

		arch_timer_stop(evt);

		break;

	}



static struct clock_event_device arch_timer_global_evt;

	return NOTIFY_OK;

}



static struct notifier_block arch_timer_cpu_nb __cpuinitdata = {

	.notifier_call = arch_timer_cpu_notify,

};



static int __init arch_timer_register(void)

{
@@ -267,7 +280,7 @@ static int __init arch_timer_register(void) 
	if (err)

		goto out;



	arch_timer_evt = alloc_percpu(struct clock_event_device *);

	arch_timer_evt = alloc_percpu(struct clock_event_device);

	if (!arch_timer_evt) {

		err = -ENOMEM;

		goto out;
@@ -303,20 +316,13 @@ static int __init arch_timer_register(void) 
		goto out_free;

	}



	err = local_timer_register(&arch_timer_ops);

	if (err) {

		/*

		 * We couldn't register as a local timer (could be

		 * because we're on a UP platform, or because some

		 * other local timer is already present...). Try as a

		 * global timer instead.

		 */

		arch_timer_global_evt.cpumask = cpumask_of(0);

		err = arch_timer_setup(&arch_timer_global_evt);

	}

	err = register_cpu_notifier(&arch_timer_cpu_nb);

	if (err)

		goto out_free_irq;



	/* Immediately configure the timer on the boot CPU */

	arch_timer_setup(this_cpu_ptr(arch_timer_evt));



	/* Use the architected timer for the delay loop. */

	arch_delay_timer.read_current_timer = &arch_timer_read_current_timer;

	arch_delay_timer.freq = arch_timer_rate;