Commit 8a4da6e3 authored by Mark Rutland's avatar Mark Rutland
Browse files

arm: arch_timer: move core to drivers/clocksource 



The core functionality of the arch_timer driver is not directly tied to
anything under arch/arm, and can be split out.

This patch factors out the core of the arch_timer driver, so it can be
shared with other architectures. A couple of functions are added so
that architecture-specific code can interact with the driver without
needing to touch its internals.

The ARM_ARCH_TIMER config variable is moved out to
drivers/clocksource/Kconfig, existing uses in arch/arm are replaced with
HAVE_ARM_ARCH_TIMER, which selects it.

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>
parent b2deabe3

arch/arm/Kconfig

+2 −1
Original line number Diff line number Diff line
@@ -1572,9 +1572,10 @@ config HAVE_ARM_SCU 
	help

	  This option enables support for the ARM system coherency unit



config ARM_ARCH_TIMER

config HAVE_ARM_ARCH_TIMER

	bool "Architected timer support"

	depends on CPU_V7

	select ARM_ARCH_TIMER

	help

	  This option enables support for the ARM architected timer

arch/arm/include/asm/arch_timer.h

+3 −16
Original line number Diff line number Diff line
@@ -4,22 +4,14 @@ 
#include <asm/barrier.h>

#include <asm/errno.h>

#include <linux/clocksource.h>

#include <linux/init.h>

#include <linux/types.h>



#include <clocksource/arm_arch_timer.h>



#ifdef CONFIG_ARM_ARCH_TIMER

int arch_timer_of_register(void);

int arch_timer_sched_clock_init(void);

struct timecounter *arch_timer_get_timecounter(void);



#define ARCH_TIMER_CTRL_ENABLE		(1 << 0)

#define ARCH_TIMER_CTRL_IT_MASK		(1 << 1)

#define ARCH_TIMER_CTRL_IT_STAT		(1 << 2)



#define ARCH_TIMER_REG_CTRL		0

#define ARCH_TIMER_REG_TVAL		1



#define ARCH_TIMER_PHYS_ACCESS		0

#define ARCH_TIMER_VIRT_ACCESS		1



/*

 * These register accessors are marked inline so the compiler can
@@ -128,11 +120,6 @@ static inline int arch_timer_sched_clock_init(void) 
{

	return -ENXIO;

}



static inline struct timecounter *arch_timer_get_timecounter(void)

{

	return NULL;

}

#endif



#endif

arch/arm/kernel/arch_timer.c

+18 −368
Original line number Diff line number Diff line
@@ -9,402 +9,52 @@ 
 * published by the Free Software Foundation.

 */

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/delay.h>

#include <linux/device.h>

#include <linux/smp.h>

#include <linux/cpu.h>

#include <linux/jiffies.h>

#include <linux/clockchips.h>

#include <linux/interrupt.h>

#include <linux/of_irq.h>

#include <linux/io.h>

#include <linux/types.h>



#include <asm/delay.h>

#include <asm/arch_timer.h>

#include <asm/sched_clock.h>



static u32 arch_timer_rate;

#include <clocksource/arm_arch_timer.h>



enum ppi_nr {

	PHYS_SECURE_PPI,

	PHYS_NONSECURE_PPI,

	VIRT_PPI,

	HYP_PPI,

	MAX_TIMER_PPI

};



static int arch_timer_ppi[MAX_TIMER_PPI];



static struct clock_event_device __percpu *arch_timer_evt;

static struct delay_timer arch_delay_timer;



static bool arch_timer_use_virtual = true;



/*

 * Architected system timer support.

 */



static irqreturn_t inline timer_handler(const int access,

					struct clock_event_device *evt)

{

	unsigned long ctrl;

	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL);

	if (ctrl & ARCH_TIMER_CTRL_IT_STAT) {

		ctrl |= ARCH_TIMER_CTRL_IT_MASK;

		arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);

		evt->event_handler(evt);

		return IRQ_HANDLED;

	}



	return IRQ_NONE;

}



static irqreturn_t arch_timer_handler_virt(int irq, void *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 = dev_id;



	return timer_handler(ARCH_TIMER_PHYS_ACCESS, evt);

}



static inline void timer_set_mode(const int access, int mode)

{

	unsigned long ctrl;

	switch (mode) {

	case CLOCK_EVT_MODE_UNUSED:

	case CLOCK_EVT_MODE_SHUTDOWN:

		ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL);

		ctrl &= ~ARCH_TIMER_CTRL_ENABLE;

		arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);

		break;

	default:

		break;

	}

}



static void arch_timer_set_mode_virt(enum clock_event_mode mode,

				     struct clock_event_device *clk)

{

	timer_set_mode(ARCH_TIMER_VIRT_ACCESS, mode);

}



static void arch_timer_set_mode_phys(enum clock_event_mode mode,

				     struct clock_event_device *clk)

{

	timer_set_mode(ARCH_TIMER_PHYS_ACCESS, mode);

}



static inline void set_next_event(const int access, unsigned long evt)

{

	unsigned long ctrl;

	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL);

	ctrl |= ARCH_TIMER_CTRL_ENABLE;

	ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;

	arch_timer_reg_write(access, ARCH_TIMER_REG_TVAL, evt);

	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);

}



static int arch_timer_set_next_event_virt(unsigned long evt,

					  struct clock_event_device *unused)

{

	set_next_event(ARCH_TIMER_VIRT_ACCESS, evt);

	return 0;

}



static int arch_timer_set_next_event_phys(unsigned long evt,

					  struct clock_event_device *unused)

{

	set_next_event(ARCH_TIMER_PHYS_ACCESS, evt);

	return 0;

}



static int __cpuinit arch_timer_setup(struct clock_event_device *clk)

{

	clk->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP;

	clk->name = "arch_sys_timer";

	clk->rating = 450;

	if (arch_timer_use_virtual) {

		clk->irq = arch_timer_ppi[VIRT_PPI];

		clk->set_mode = arch_timer_set_mode_virt;

		clk->set_next_event = arch_timer_set_next_event_virt;

	} else {

		clk->irq = arch_timer_ppi[PHYS_SECURE_PPI];

		clk->set_mode = arch_timer_set_mode_phys;

		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);



	if (arch_timer_use_virtual)

		enable_percpu_irq(arch_timer_ppi[VIRT_PPI], 0);

	else {

		enable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI], 0);

		if (arch_timer_ppi[PHYS_NONSECURE_PPI])

			enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], 0);

	}



	arch_counter_set_user_access();



	return 0;

}



static int arch_timer_available(void)

{

	u32 freq;



	if (arch_timer_rate == 0) {

		freq = arch_timer_get_cntfrq();



		/* Check the timer frequency. */

		if (freq == 0) {

			pr_warn("Architected timer frequency not available\n");

			return -EINVAL;

		}



		arch_timer_rate = freq;

	}



	pr_info_once("Architected local timer running at %lu.%02luMHz (%s).\n",

		     (unsigned long)arch_timer_rate / 1000000,

		     (unsigned long)(arch_timer_rate / 10000) % 100,

		     arch_timer_use_virtual ? "virt" : "phys");

	return 0;

}



/*

 * Some external users of arch_timer_read_counter (e.g. sched_clock) may try to

 * call it before it has been initialised. Rather than incur a performance

 * penalty checking for initialisation, provide a default implementation that

 * won't lead to time appearing to jump backwards.

 */

static u64 arch_timer_read_zero(void)

{

	return 0;

}



u64 (*arch_timer_read_counter)(void) = arch_timer_read_zero;



static u32 arch_timer_read_counter32(void)

{

	return arch_timer_read_counter();

}



static cycle_t arch_counter_read(struct clocksource *cs)

{

	return arch_timer_read_counter();

}



static unsigned long arch_timer_read_current_timer(void)

static unsigned long arch_timer_read_counter_long(void)

{

	return arch_timer_read_counter();

}



static cycle_t arch_counter_read_cc(const struct cyclecounter *cc)

static u32 arch_timer_read_counter_u32(void)

{

	return arch_timer_read_counter();

}



static struct clocksource clocksource_counter = {

	.name	= "arch_sys_counter",

	.rating	= 400,

	.read	= arch_counter_read,

	.mask	= CLOCKSOURCE_MASK(56),

	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,

};



static struct cyclecounter cyclecounter = {

	.read	= arch_counter_read_cc,

	.mask	= CLOCKSOURCE_MASK(56),

};



static struct timecounter timecounter;



struct timecounter *arch_timer_get_timecounter(void)

{

	return &timecounter;

}



static void __cpuinit arch_timer_stop(struct clock_event_device *clk)

{

	pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n",

		 clk->irq, smp_processor_id());



	if (arch_timer_use_virtual)

		disable_percpu_irq(arch_timer_ppi[VIRT_PPI]);

	else {

		disable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI]);

		if (arch_timer_ppi[PHYS_NONSECURE_PPI])

			disable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI]);

	}



	clk->set_mode(CLOCK_EVT_MODE_UNUSED, clk);

}



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;

	}



	return NOTIFY_OK;

}



static struct notifier_block arch_timer_cpu_nb __cpuinitdata = {

	.notifier_call = arch_timer_cpu_notify,

};

static struct delay_timer arch_delay_timer;



static int __init arch_timer_register(void)

static void __init arch_timer_delay_timer_register(void)

{

	int err;

	int ppi;



	err = arch_timer_available();

	if (err)

		goto out;



	arch_timer_evt = alloc_percpu(struct clock_event_device);

	if (!arch_timer_evt) {

		err = -ENOMEM;

		goto out;

	}



	clocksource_register_hz(&clocksource_counter, arch_timer_rate);

	cyclecounter.mult = clocksource_counter.mult;

	cyclecounter.shift = clocksource_counter.shift;

	timecounter_init(&timecounter, &cyclecounter,

			 arch_counter_get_cntpct());



	if (arch_timer_use_virtual) {

		ppi = arch_timer_ppi[VIRT_PPI];

		err = request_percpu_irq(ppi, arch_timer_handler_virt,

					 "arch_timer", arch_timer_evt);

	} else {

		ppi = arch_timer_ppi[PHYS_SECURE_PPI];

		err = request_percpu_irq(ppi, arch_timer_handler_phys,

					 "arch_timer", arch_timer_evt);

		if (!err && arch_timer_ppi[PHYS_NONSECURE_PPI]) {

			ppi = arch_timer_ppi[PHYS_NONSECURE_PPI];

			err = request_percpu_irq(ppi, arch_timer_handler_phys,

						 "arch_timer", arch_timer_evt);

			if (err)

				free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],

						arch_timer_evt);

		}

	}



	if (err) {

		pr_err("arch_timer: can't register interrupt %d (%d)\n",

		       ppi, err);

		goto out_free;

	}



	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;

	arch_delay_timer.read_current_timer = arch_timer_read_counter_long;

	arch_delay_timer.freq = arch_timer_get_rate();

	register_current_timer_delay(&arch_delay_timer);

	return 0;



out_free_irq:

	if (arch_timer_use_virtual)

		free_percpu_irq(arch_timer_ppi[VIRT_PPI], arch_timer_evt);

	else {

		free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],

				arch_timer_evt);

		if (arch_timer_ppi[PHYS_NONSECURE_PPI])

			free_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI],

					arch_timer_evt);

}



out_free:

	free_percpu(arch_timer_evt);

out:

	return err;

}



static const struct of_device_id arch_timer_of_match[] __initconst = {

	{ .compatible	= "arm,armv7-timer",	},

	{},

};



int __init arch_timer_of_register(void)

{

	struct device_node *np;

	u32 freq;

	int i;



	np = of_find_matching_node(NULL, arch_timer_of_match);

	if (!np) {

		pr_err("arch_timer: can't find DT node\n");

		return -ENODEV;

	}



	/* Try to determine the frequency from the device tree or CNTFRQ */

	if (!of_property_read_u32(np, "clock-frequency", &freq))

		arch_timer_rate = freq;

	int ret;



	for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)

		arch_timer_ppi[i] = irq_of_parse_and_map(np, i);

	ret = arch_timer_init();

	if (ret)

		return ret;



	of_node_put(np);

	arch_timer_delay_timer_register();



	/*

	 * If no interrupt provided for virtual timer, we'll have to

	 * stick to the physical timer. It'd better be accessible...

	 */

	if (!arch_timer_ppi[VIRT_PPI]) {

		arch_timer_use_virtual = false;



		if (!arch_timer_ppi[PHYS_SECURE_PPI] ||

		    !arch_timer_ppi[PHYS_NONSECURE_PPI]) {

			pr_warn("arch_timer: No interrupt available, giving up\n");

			return -EINVAL;

		}

	}



	if (arch_timer_use_virtual)

		arch_timer_read_counter = arch_counter_get_cntvct;

	else

		arch_timer_read_counter = arch_counter_get_cntpct;



	return arch_timer_register();

	return 0;

}



int __init arch_timer_sched_clock_init(void)

{

	int err;



	err = arch_timer_available();

	if (err)

		return err;

	if (arch_timer_get_rate() == 0)

		return -ENXIO;



	setup_sched_clock(arch_timer_read_counter32,

			  32, arch_timer_rate);

	setup_sched_clock(arch_timer_read_counter_u32,

			  32, arch_timer_get_rate());

	return 0;

}

arch/arm/mach-omap2/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -76,12 +76,12 @@ config ARCH_OMAP4 


config SOC_OMAP5

	bool "TI OMAP5"

	select ARM_ARCH_TIMER

	select ARM_CPU_SUSPEND if PM

	select ARM_GIC

	select CPU_V7

	select HAVE_SMP

	select COMMON_CLK

	select HAVE_ARM_ARCH_TIMER



comment "OMAP Core Type"

	depends on ARCH_OMAP2

drivers/clocksource/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -58,3 +58,6 @@ config CLKSRC_ARM_GENERIC 
	def_bool y if ARM64

	help

	  This option enables support for the ARM generic timer.



config ARM_ARCH_TIMER

	bool

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