arch/arm/kernel/arch_timer.c - maze/linux - Git at Google

 /*
  *  linux/arch/arm/kernel/arch_timer.c
  *
  *  Copyright (C) 2011 ARM Ltd.
  *  All Rights Reserved
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * 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 <asm/cputype.h>
 #include <asm/localtimer.h>
 #include <asm/arch_timer.h>
 #include <asm/system_info.h>
 #include <asm/sched_clock.h>

 static unsigned long arch_timer_rate;
 static int arch_timer_ppi;
 static int arch_timer_ppi2;

 static struct clock_event_device __percpu **arch_timer_evt;

 /*
  * Architected system timer support.
  */

 #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_FREQ		1
 #define ARCH_TIMER_REG_TVAL		2

 static void arch_timer_reg_write(int reg, u32 val)
 {
 	switch (reg) {
 	case ARCH_TIMER_REG_CTRL:
 		asm volatile("mcr p15, 0, %0, c14, c2, 1" : : "r" (val));
 		break;
 	case ARCH_TIMER_REG_TVAL:
 		asm volatile("mcr p15, 0, %0, c14, c2, 0" : : "r" (val));
 		break;
 	}

 	isb();
 }

 static u32 arch_timer_reg_read(int reg)
 {
 	u32 val;

 	switch (reg) {
 	case ARCH_TIMER_REG_CTRL:
 		asm volatile("mrc p15, 0, %0, c14, c2, 1" : "=r" (val));
 		break;
 	case ARCH_TIMER_REG_FREQ:
 		asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (val));
 		break;
 	case ARCH_TIMER_REG_TVAL:
 		asm volatile("mrc p15, 0, %0, c14, c2, 0" : "=r" (val));
 		break;
 	default:
 		BUG();
 	}

 	return val;
 }

 static irqreturn_t arch_timer_handler(int irq, void *dev_id)
 {
 	struct clock_event_device *evt = *(struct clock_event_device **)dev_id;
 	unsigned long ctrl;

 	ctrl = arch_timer_reg_read(ARCH_TIMER_REG_CTRL);
 	if (ctrl & ARCH_TIMER_CTRL_IT_STAT) {
 		ctrl |= ARCH_TIMER_CTRL_IT_MASK;
 		arch_timer_reg_write(ARCH_TIMER_REG_CTRL, ctrl);
 		evt->event_handler(evt);
 		return IRQ_HANDLED;
 	}

 	return IRQ_NONE;
 }

 static void arch_timer_disable(void)
 {
 	unsigned long ctrl;

 	ctrl = arch_timer_reg_read(ARCH_TIMER_REG_CTRL);
 	ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
 	arch_timer_reg_write(ARCH_TIMER_REG_CTRL, ctrl);
 }

 static void arch_timer_set_mode(enum clock_event_mode mode,
 				struct clock_event_device *clk)
 {
 	switch (mode) {
 	case CLOCK_EVT_MODE_UNUSED:
 	case CLOCK_EVT_MODE_SHUTDOWN:
 		arch_timer_disable();
 		break;
 	default:
 		break;
 	}
 }

 static int arch_timer_set_next_event(unsigned long evt,
 				     struct clock_event_device *unused)
 {
 	unsigned long ctrl;

 	ctrl = arch_timer_reg_read(ARCH_TIMER_REG_CTRL);
 	ctrl |= ARCH_TIMER_CTRL_ENABLE;
 	ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;

 	arch_timer_reg_write(ARCH_TIMER_REG_TVAL, evt);
 	arch_timer_reg_write(ARCH_TIMER_REG_CTRL, ctrl);

 	return 0;
 }

 static int __cpuinit arch_timer_setup(struct clock_event_device *clk)
 {
 	/* Be safe... */
 	arch_timer_disable();

 	clk->features = CLOCK_EVT_FEAT_ONESHOT;
 	clk->name = "arch_sys_timer";
 	clk->rating = 450;
 	clk->set_mode = arch_timer_set_mode;
 	clk->set_next_event = arch_timer_set_next_event;
 	clk->irq = arch_timer_ppi;

 	clockevents_config_and_register(clk, arch_timer_rate,
 					0xf, 0x7fffffff);

 	*__this_cpu_ptr(arch_timer_evt) = clk;

 	enable_percpu_irq(clk->irq, 0);
 	if (arch_timer_ppi2)
 		enable_percpu_irq(arch_timer_ppi2, 0);

 	return 0;
 }

 /* Is the optional system timer available? */
 static int local_timer_is_architected(void)
 {
 	return (cpu_architecture() >= CPU_ARCH_ARMv7) &&
 	       ((read_cpuid_ext(CPUID_EXT_PFR1) >> 16) & 0xf) == 1;
 }

 static int arch_timer_available(void)
 {
 	unsigned long freq;

 	if (!local_timer_is_architected())
 		return -ENXIO;

 	if (arch_timer_rate == 0) {
 		arch_timer_reg_write(ARCH_TIMER_REG_CTRL, 0);
 		freq = arch_timer_reg_read(ARCH_TIMER_REG_FREQ);

 		/* 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.\n",
 		     arch_timer_rate / 1000000, (arch_timer_rate / 10000) % 100);
 	return 0;
 }

 static inline cycle_t arch_counter_get_cntpct(void)
 {
 	u32 cvall, cvalh;

 	asm volatile("mrrc p15, 0, %0, %1, c14" : "=r" (cvall), "=r" (cvalh));

 	return ((cycle_t) cvalh << 32) | cvall;
 }

 static inline cycle_t arch_counter_get_cntvct(void)
 {
 	u32 cvall, cvalh;

 	asm volatile("mrrc p15, 1, %0, %1, c14" : "=r" (cvall), "=r" (cvalh));

 	return ((cycle_t) cvalh << 32) | cvall;
 }

 static u32 notrace arch_counter_get_cntvct32(void)
 {
 	cycle_t cntvct = arch_counter_get_cntvct();

 	/*
 	 * The sched_clock infrastructure only knows about counters
 	 * with at most 32bits. Forget about the upper 24 bits for the
 	 * time being...
 	 */
 	return (u32)(cntvct & (u32)~0);
 }

 static cycle_t arch_counter_read(struct clocksource *cs)
 {
 	return arch_counter_get_cntpct();
 }

 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 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());
 	disable_percpu_irq(clk->irq);
 	if (arch_timer_ppi2)
 		disable_percpu_irq(arch_timer_ppi2);
 	arch_timer_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 struct clock_event_device arch_timer_global_evt;

 static int __init arch_timer_register(void)
 {
 	int err;

 	err = arch_timer_available();
 	if (err)
 		return err;

 	arch_timer_evt = alloc_percpu(struct clock_event_device *);
 	if (!arch_timer_evt)
 		return -ENOMEM;

 	clocksource_register_hz(&clocksource_counter, arch_timer_rate);

 	err = request_percpu_irq(arch_timer_ppi, arch_timer_handler,
 				 "arch_timer", arch_timer_evt);
 	if (err) {
 		pr_err("arch_timer: can't register interrupt %d (%d)\n",
 		       arch_timer_ppi, err);
 		goto out_free;
 	}

 	if (arch_timer_ppi2) {
 		err = request_percpu_irq(arch_timer_ppi2, arch_timer_handler,
 					 "arch_timer", arch_timer_evt);
 		if (err) {
 			pr_err("arch_timer: can't register interrupt %d (%d)\n",
 			       arch_timer_ppi2, err);
 			arch_timer_ppi2 = 0;
 			goto out_free_irq;
 		}
 	}

 	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);
 	}

 	if (err)
 		goto out_free_irq;

 	return 0;

 out_free_irq:
 	free_percpu_irq(arch_timer_ppi, arch_timer_evt);
 	if (arch_timer_ppi2)
 		free_percpu_irq(arch_timer_ppi2, arch_timer_evt);

 out_free:
 	free_percpu(arch_timer_evt);

 	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;

 	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;

 	arch_timer_ppi = irq_of_parse_and_map(np, 0);
 	arch_timer_ppi2 = irq_of_parse_and_map(np, 1);
 	pr_info("arch_timer: found %s irqs %d %d\n",
 		np->name, arch_timer_ppi, arch_timer_ppi2);

 	return arch_timer_register();
 }

 int __init arch_timer_sched_clock_init(void)
 {
 	int err;

 	err = arch_timer_available();
 	if (err)
 		return err;

 	setup_sched_clock(arch_counter_get_cntvct32, 32, arch_timer_rate);
 	return 0;
 }
	/*
	* linux/arch/arm/kernel/arch_timer.c
	*
	* Copyright (C) 2011 ARM Ltd.
	* All Rights Reserved
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* 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 <asm/cputype.h>
	#include <asm/localtimer.h>
	#include <asm/arch_timer.h>
	#include <asm/system_info.h>
	#include <asm/sched_clock.h>

	static unsigned long arch_timer_rate;
	static int arch_timer_ppi;
	static int arch_timer_ppi2;

	static struct clock_event_device __percpu **arch_timer_evt;

	/*
	* Architected system timer support.
	*/

	#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_FREQ 1
	#define ARCH_TIMER_REG_TVAL 2

	static void arch_timer_reg_write(int reg, u32 val)
	{
	switch (reg) {
	case ARCH_TIMER_REG_CTRL:
	asm volatile("mcr p15, 0, %0, c14, c2, 1" : : "r" (val));
	break;
	case ARCH_TIMER_REG_TVAL:
	asm volatile("mcr p15, 0, %0, c14, c2, 0" : : "r" (val));
	break;
	}

	isb();
	}

	static u32 arch_timer_reg_read(int reg)
	{
	u32 val;

	switch (reg) {
	case ARCH_TIMER_REG_CTRL:
	asm volatile("mrc p15, 0, %0, c14, c2, 1" : "=r" (val));
	break;
	case ARCH_TIMER_REG_FREQ:
	asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (val));
	break;
	case ARCH_TIMER_REG_TVAL:
	asm volatile("mrc p15, 0, %0, c14, c2, 0" : "=r" (val));
	break;
	default:
	BUG();
	}

	return val;
	}

	static irqreturn_t arch_timer_handler(int irq, void *dev_id)
	{
	struct clock_event_device evt = (struct clock_event_device **)dev_id;
	unsigned long ctrl;

	ctrl = arch_timer_reg_read(ARCH_TIMER_REG_CTRL);
	if (ctrl & ARCH_TIMER_CTRL_IT_STAT) {
	ctrl \|= ARCH_TIMER_CTRL_IT_MASK;
	arch_timer_reg_write(ARCH_TIMER_REG_CTRL, ctrl);
	evt->event_handler(evt);
	return IRQ_HANDLED;
	}

	return IRQ_NONE;
	}

	static void arch_timer_disable(void)
	{
	unsigned long ctrl;

	ctrl = arch_timer_reg_read(ARCH_TIMER_REG_CTRL);
	ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
	arch_timer_reg_write(ARCH_TIMER_REG_CTRL, ctrl);
	}

	static void arch_timer_set_mode(enum clock_event_mode mode,
	struct clock_event_device *clk)
	{
	switch (mode) {
	case CLOCK_EVT_MODE_UNUSED:
	case CLOCK_EVT_MODE_SHUTDOWN:
	arch_timer_disable();
	break;
	default:
	break;
	}
	}

	static int arch_timer_set_next_event(unsigned long evt,
	struct clock_event_device *unused)
	{
	unsigned long ctrl;

	ctrl = arch_timer_reg_read(ARCH_TIMER_REG_CTRL);
	ctrl \|= ARCH_TIMER_CTRL_ENABLE;
	ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;

	arch_timer_reg_write(ARCH_TIMER_REG_TVAL, evt);
	arch_timer_reg_write(ARCH_TIMER_REG_CTRL, ctrl);

	return 0;
	}

	static int __cpuinit arch_timer_setup(struct clock_event_device *clk)
	{
	/* Be safe... */
	arch_timer_disable();

	clk->features = CLOCK_EVT_FEAT_ONESHOT;
	clk->name = "arch_sys_timer";
	clk->rating = 450;
	clk->set_mode = arch_timer_set_mode;
	clk->set_next_event = arch_timer_set_next_event;
	clk->irq = arch_timer_ppi;

	clockevents_config_and_register(clk, arch_timer_rate,
	0xf, 0x7fffffff);

	*__this_cpu_ptr(arch_timer_evt) = clk;

	enable_percpu_irq(clk->irq, 0);
	if (arch_timer_ppi2)
	enable_percpu_irq(arch_timer_ppi2, 0);

	return 0;
	}

	/* Is the optional system timer available? */
	static int local_timer_is_architected(void)
	{
	return (cpu_architecture() >= CPU_ARCH_ARMv7) &&
	((read_cpuid_ext(CPUID_EXT_PFR1) >> 16) & 0xf) == 1;
	}

	static int arch_timer_available(void)
	{
	unsigned long freq;

	if (!local_timer_is_architected())
	return -ENXIO;

	if (arch_timer_rate == 0) {
	arch_timer_reg_write(ARCH_TIMER_REG_CTRL, 0);
	freq = arch_timer_reg_read(ARCH_TIMER_REG_FREQ);

	/* 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.\n",
	arch_timer_rate / 1000000, (arch_timer_rate / 10000) % 100);
	return 0;
	}

	static inline cycle_t arch_counter_get_cntpct(void)
	{
	u32 cvall, cvalh;

	asm volatile("mrrc p15, 0, %0, %1, c14" : "=r" (cvall), "=r" (cvalh));

	return ((cycle_t) cvalh << 32) \| cvall;
	}

	static inline cycle_t arch_counter_get_cntvct(void)
	{
	u32 cvall, cvalh;

	asm volatile("mrrc p15, 1, %0, %1, c14" : "=r" (cvall), "=r" (cvalh));

	return ((cycle_t) cvalh << 32) \| cvall;
	}

	static u32 notrace arch_counter_get_cntvct32(void)
	{
	cycle_t cntvct = arch_counter_get_cntvct();

	/*
	* The sched_clock infrastructure only knows about counters
	* with at most 32bits. Forget about the upper 24 bits for the
	* time being...
	*/
	return (u32)(cntvct & (u32)~0);
	}

	static cycle_t arch_counter_read(struct clocksource *cs)
	{
	return arch_counter_get_cntpct();
	}

	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 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());
	disable_percpu_irq(clk->irq);
	if (arch_timer_ppi2)
	disable_percpu_irq(arch_timer_ppi2);
	arch_timer_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 struct clock_event_device arch_timer_global_evt;

	static int __init arch_timer_register(void)
	{
	int err;

	err = arch_timer_available();
	if (err)
	return err;

	arch_timer_evt = alloc_percpu(struct clock_event_device *);
	if (!arch_timer_evt)
	return -ENOMEM;

	clocksource_register_hz(&clocksource_counter, arch_timer_rate);

	err = request_percpu_irq(arch_timer_ppi, arch_timer_handler,
	"arch_timer", arch_timer_evt);
	if (err) {
	pr_err("arch_timer: can't register interrupt %d (%d)\n",
	arch_timer_ppi, err);
	goto out_free;
	}

	if (arch_timer_ppi2) {
	err = request_percpu_irq(arch_timer_ppi2, arch_timer_handler,
	"arch_timer", arch_timer_evt);
	if (err) {
	pr_err("arch_timer: can't register interrupt %d (%d)\n",
	arch_timer_ppi2, err);
	arch_timer_ppi2 = 0;
	goto out_free_irq;
	}
	}

	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);
	}

	if (err)
	goto out_free_irq;

	return 0;

	out_free_irq:
	free_percpu_irq(arch_timer_ppi, arch_timer_evt);
	if (arch_timer_ppi2)
	free_percpu_irq(arch_timer_ppi2, arch_timer_evt);

	out_free:
	free_percpu(arch_timer_evt);

	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;

	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;

	arch_timer_ppi = irq_of_parse_and_map(np, 0);
	arch_timer_ppi2 = irq_of_parse_and_map(np, 1);
	pr_info("arch_timer: found %s irqs %d %d\n",
	np->name, arch_timer_ppi, arch_timer_ppi2);

	return arch_timer_register();
	}

	int __init arch_timer_sched_clock_init(void)
	{
	int err;

	err = arch_timer_available();
	if (err)
	return err;

	setup_sched_clock(arch_counter_get_cntvct32, 32, arch_timer_rate);
	return 0;
	}