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

 /*
  *  linux/arch/arm/kernel/smp_twd.c
  *
  *  Copyright (C) 2002 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/clk.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/smp.h>
 #include <linux/jiffies.h>
 #include <linux/clockchips.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/of_irq.h>
 #include <linux/of_address.h>

 #include <asm/smp_plat.h>
 #include <asm/smp_twd.h>
 #include <asm/localtimer.h>

 /* set up by the platform code */
 static void __iomem *twd_base;

 static struct clk *twd_clk;
 static unsigned long twd_timer_rate;
 static DEFINE_PER_CPU(bool, percpu_setup_called);

 static struct clock_event_device __percpu **twd_evt;
 static int twd_ppi;

 static void twd_set_mode(enum clock_event_mode mode,
 			struct clock_event_device *clk)
 {
 	unsigned long ctrl;

 	switch (mode) {
 	case CLOCK_EVT_MODE_PERIODIC:
 		ctrl = TWD_TIMER_CONTROL_ENABLE | TWD_TIMER_CONTROL_IT_ENABLE
 			| TWD_TIMER_CONTROL_PERIODIC;
 		__raw_writel(DIV_ROUND_CLOSEST(twd_timer_rate, HZ),
 			twd_base + TWD_TIMER_LOAD);
 		break;
 	case CLOCK_EVT_MODE_ONESHOT:
 		/* period set, and timer enabled in 'next_event' hook */
 		ctrl = TWD_TIMER_CONTROL_IT_ENABLE | TWD_TIMER_CONTROL_ONESHOT;
 		break;
 	case CLOCK_EVT_MODE_UNUSED:
 	case CLOCK_EVT_MODE_SHUTDOWN:
 	default:
 		ctrl = 0;
 	}

 	__raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);
 }

 static int twd_set_next_event(unsigned long evt,
 			struct clock_event_device *unused)
 {
 	unsigned long ctrl = __raw_readl(twd_base + TWD_TIMER_CONTROL);

 	ctrl |= TWD_TIMER_CONTROL_ENABLE;

 	__raw_writel(evt, twd_base + TWD_TIMER_COUNTER);
 	__raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);

 	return 0;
 }

 /*
  * local_timer_ack: checks for a local timer interrupt.
  *
  * If a local timer interrupt has occurred, acknowledge and return 1.
  * Otherwise, return 0.
  */
 static int twd_timer_ack(void)
 {
 	if (__raw_readl(twd_base + TWD_TIMER_INTSTAT)) {
 		__raw_writel(1, twd_base + TWD_TIMER_INTSTAT);
 		return 1;
 	}

 	return 0;
 }

 static void twd_timer_stop(struct clock_event_device *clk)
 {
 	twd_set_mode(CLOCK_EVT_MODE_UNUSED, clk);
 	disable_percpu_irq(clk->irq);
 }

 #ifdef CONFIG_COMMON_CLK

 /*
  * Updates clockevent frequency when the cpu frequency changes.
  * Called on the cpu that is changing frequency with interrupts disabled.
  */
 static void twd_update_frequency(void *new_rate)
 {
 	twd_timer_rate = *((unsigned long *) new_rate);

 	clockevents_update_freq(*__this_cpu_ptr(twd_evt), twd_timer_rate);
 }

 static int twd_rate_change(struct notifier_block *nb,
 	unsigned long flags, void *data)
 {
 	struct clk_notifier_data *cnd = data;

 	/*
 	 * The twd clock events must be reprogrammed to account for the new
 	 * frequency.  The timer is local to a cpu, so cross-call to the
 	 * changing cpu.
 	 */
 	if (flags == POST_RATE_CHANGE)
 		on_each_cpu(twd_update_frequency,
 				  (void *)&cnd->new_rate, 1);

 	return NOTIFY_OK;
 }

 static struct notifier_block twd_clk_nb = {
 	.notifier_call = twd_rate_change,
 };

 static int twd_clk_init(void)
 {
 	if (twd_evt && *__this_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
 		return clk_notifier_register(twd_clk, &twd_clk_nb);

 	return 0;
 }
 core_initcall(twd_clk_init);

 #elif defined (CONFIG_CPU_FREQ)

 #include <linux/cpufreq.h>

 /*
  * Updates clockevent frequency when the cpu frequency changes.
  * Called on the cpu that is changing frequency with interrupts disabled.
  */
 static void twd_update_frequency(void *data)
 {
 	twd_timer_rate = clk_get_rate(twd_clk);

 	clockevents_update_freq(*__this_cpu_ptr(twd_evt), twd_timer_rate);
 }

 static int twd_cpufreq_transition(struct notifier_block *nb,
 	unsigned long state, void *data)
 {
 	struct cpufreq_freqs *freqs = data;

 	/*
 	 * The twd clock events must be reprogrammed to account for the new
 	 * frequency.  The timer is local to a cpu, so cross-call to the
 	 * changing cpu.
 	 */
 	if (state == CPUFREQ_POSTCHANGE || state == CPUFREQ_RESUMECHANGE)
 		smp_call_function_single(freqs->cpu, twd_update_frequency,
 			NULL, 1);

 	return NOTIFY_OK;
 }

 static struct notifier_block twd_cpufreq_nb = {
 	.notifier_call = twd_cpufreq_transition,
 };

 static int twd_cpufreq_init(void)
 {
 	if (twd_evt && *__this_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
 		return cpufreq_register_notifier(&twd_cpufreq_nb,
 			CPUFREQ_TRANSITION_NOTIFIER);

 	return 0;
 }
 core_initcall(twd_cpufreq_init);

 #endif

 static void twd_calibrate_rate(void)
 {
 	unsigned long count;
 	u64 waitjiffies;

 	/*
 	 * If this is the first time round, we need to work out how fast
 	 * the timer ticks
 	 */
 	if (twd_timer_rate == 0) {
 		printk(KERN_INFO "Calibrating local timer... ");

 		/* Wait for a tick to start */
 		waitjiffies = get_jiffies_64() + 1;

 		while (get_jiffies_64() < waitjiffies)
 			udelay(10);

 		/* OK, now the tick has started, let's get the timer going */
 		waitjiffies += 5;

 				 /* enable, no interrupt or reload */
 		__raw_writel(0x1, twd_base + TWD_TIMER_CONTROL);

 				 /* maximum value */
 		__raw_writel(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER);

 		while (get_jiffies_64() < waitjiffies)
 			udelay(10);

 		count = __raw_readl(twd_base + TWD_TIMER_COUNTER);

 		twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);

 		printk("%lu.%02luMHz.\n", twd_timer_rate / 1000000,
 			(twd_timer_rate / 10000) % 100);
 	}
 }

 static irqreturn_t twd_handler(int irq, void *dev_id)
 {
 	struct clock_event_device *evt = *(struct clock_event_device **)dev_id;

 	if (twd_timer_ack()) {
 		evt->event_handler(evt);
 		return IRQ_HANDLED;
 	}

 	return IRQ_NONE;
 }

 static void twd_get_clock(struct device_node *np)
 {
 	int err;

 	if (np)
 		twd_clk = of_clk_get(np, 0);
 	else
 		twd_clk = clk_get_sys("smp_twd", NULL);

 	if (IS_ERR(twd_clk)) {
 		pr_err("smp_twd: clock not found %d\n", (int) PTR_ERR(twd_clk));
 		return;
 	}

 	err = clk_prepare_enable(twd_clk);
 	if (err) {
 		pr_err("smp_twd: clock failed to prepare+enable: %d\n", err);
 		clk_put(twd_clk);
 		return;
 	}

 	twd_timer_rate = clk_get_rate(twd_clk);
 }

 /*
  * Setup the local clock events for a CPU.
  */
 static int twd_timer_setup(struct clock_event_device *clk)
 {
 	struct clock_event_device **this_cpu_clk;
 	int cpu = smp_processor_id();

 	/*
 	 * If the basic setup for this CPU has been done before don't
 	 * bother with the below.
 	 */
 	if (per_cpu(percpu_setup_called, cpu)) {
 		__raw_writel(0, twd_base + TWD_TIMER_CONTROL);
 		clockevents_register_device(*__this_cpu_ptr(twd_evt));
 		enable_percpu_irq(clk->irq, 0);
 		return 0;
 	}
 	per_cpu(percpu_setup_called, cpu) = true;

 	twd_calibrate_rate();

 	/*
 	 * The following is done once per CPU the first time .setup() is
 	 * called.
 	 */
 	__raw_writel(0, twd_base + TWD_TIMER_CONTROL);

 	clk->name = "local_timer";
 	clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
 			CLOCK_EVT_FEAT_C3STOP;
 	clk->rating = 350;
 	clk->set_mode = twd_set_mode;
 	clk->set_next_event = twd_set_next_event;
 	clk->irq = twd_ppi;

 	this_cpu_clk = __this_cpu_ptr(twd_evt);
 	*this_cpu_clk = clk;

 	clockevents_config_and_register(clk, twd_timer_rate,
 					0xf, 0xffffffff);
 	enable_percpu_irq(clk->irq, 0);

 	return 0;
 }

 static struct local_timer_ops twd_lt_ops = {
 	.setup	= twd_timer_setup,
 	.stop	= twd_timer_stop,
 };

 static int __init twd_local_timer_common_register(struct device_node *np)
 {
 	int err;

 	twd_evt = alloc_percpu(struct clock_event_device *);
 	if (!twd_evt) {
 		err = -ENOMEM;
 		goto out_free;
 	}

 	err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt);
 	if (err) {
 		pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, err);
 		goto out_free;
 	}

 	err = local_timer_register(&twd_lt_ops);
 	if (err)
 		goto out_irq;

 	twd_get_clock(np);

 	return 0;

 out_irq:
 	free_percpu_irq(twd_ppi, twd_evt);
 out_free:
 	iounmap(twd_base);
 	twd_base = NULL;
 	free_percpu(twd_evt);

 	return err;
 }

 int __init twd_local_timer_register(struct twd_local_timer *tlt)
 {
 	if (twd_base || twd_evt)
 		return -EBUSY;

 	twd_ppi	= tlt->res[1].start;

 	twd_base = ioremap(tlt->res[0].start, resource_size(&tlt->res[0]));
 	if (!twd_base)
 		return -ENOMEM;

 	return twd_local_timer_common_register(NULL);
 }

 #ifdef CONFIG_OF
 static void __init twd_local_timer_of_register(struct device_node *np)
 {
 	int err;

 	if (!is_smp() || !setup_max_cpus)
 		return;

 	twd_ppi = irq_of_parse_and_map(np, 0);
 	if (!twd_ppi) {
 		err = -EINVAL;
 		goto out;
 	}

 	twd_base = of_iomap(np, 0);
 	if (!twd_base) {
 		err = -ENOMEM;
 		goto out;
 	}

 	err = twd_local_timer_common_register(np);

 out:
 	WARN(err, "twd_local_timer_of_register failed (%d)\n", err);
 }
 CLOCKSOURCE_OF_DECLARE(arm_twd_a9, "arm,cortex-a9-twd-timer", twd_local_timer_of_register);
 CLOCKSOURCE_OF_DECLARE(arm_twd_a5, "arm,cortex-a5-twd-timer", twd_local_timer_of_register);
 CLOCKSOURCE_OF_DECLARE(arm_twd_11mp, "arm,arm11mp-twd-timer", twd_local_timer_of_register);
 #endif
	/*
	* linux/arch/arm/kernel/smp_twd.c
	*
	* Copyright (C) 2002 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/clk.h>
	#include <linux/delay.h>
	#include <linux/device.h>
	#include <linux/err.h>
	#include <linux/smp.h>
	#include <linux/jiffies.h>
	#include <linux/clockchips.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/of_irq.h>
	#include <linux/of_address.h>

	#include <asm/smp_plat.h>
	#include <asm/smp_twd.h>
	#include <asm/localtimer.h>

	/* set up by the platform code */
	static void __iomem *twd_base;

	static struct clk *twd_clk;
	static unsigned long twd_timer_rate;
	static DEFINE_PER_CPU(bool, percpu_setup_called);

	static struct clock_event_device __percpu **twd_evt;
	static int twd_ppi;

	static void twd_set_mode(enum clock_event_mode mode,
	struct clock_event_device *clk)
	{
	unsigned long ctrl;

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
	ctrl = TWD_TIMER_CONTROL_ENABLE \| TWD_TIMER_CONTROL_IT_ENABLE
	\| TWD_TIMER_CONTROL_PERIODIC;
	__raw_writel(DIV_ROUND_CLOSEST(twd_timer_rate, HZ),
	twd_base + TWD_TIMER_LOAD);
	break;
	case CLOCK_EVT_MODE_ONESHOT:
	/* period set, and timer enabled in 'next_event' hook */
	ctrl = TWD_TIMER_CONTROL_IT_ENABLE \| TWD_TIMER_CONTROL_ONESHOT;
	break;
	case CLOCK_EVT_MODE_UNUSED:
	case CLOCK_EVT_MODE_SHUTDOWN:
	default:
	ctrl = 0;
	}

	__raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);
	}

	static int twd_set_next_event(unsigned long evt,
	struct clock_event_device *unused)
	{
	unsigned long ctrl = __raw_readl(twd_base + TWD_TIMER_CONTROL);

	ctrl \|= TWD_TIMER_CONTROL_ENABLE;

	__raw_writel(evt, twd_base + TWD_TIMER_COUNTER);
	__raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);

	return 0;
	}

	/*
	* local_timer_ack: checks for a local timer interrupt.
	*
	* If a local timer interrupt has occurred, acknowledge and return 1.
	* Otherwise, return 0.
	*/
	static int twd_timer_ack(void)
	{
	if (__raw_readl(twd_base + TWD_TIMER_INTSTAT)) {
	__raw_writel(1, twd_base + TWD_TIMER_INTSTAT);
	return 1;
	}

	return 0;
	}

	static void twd_timer_stop(struct clock_event_device *clk)
	{
	twd_set_mode(CLOCK_EVT_MODE_UNUSED, clk);
	disable_percpu_irq(clk->irq);
	}

	#ifdef CONFIG_COMMON_CLK

	/*
	* Updates clockevent frequency when the cpu frequency changes.
	* Called on the cpu that is changing frequency with interrupts disabled.
	*/
	static void twd_update_frequency(void *new_rate)
	{
	twd_timer_rate = ((unsigned long ) new_rate);

	clockevents_update_freq(*__this_cpu_ptr(twd_evt), twd_timer_rate);
	}

	static int twd_rate_change(struct notifier_block *nb,
	unsigned long flags, void *data)
	{
	struct clk_notifier_data *cnd = data;

	/*
	* The twd clock events must be reprogrammed to account for the new
	* frequency. The timer is local to a cpu, so cross-call to the
	* changing cpu.
	*/
	if (flags == POST_RATE_CHANGE)
	on_each_cpu(twd_update_frequency,
	(void *)&cnd->new_rate, 1);

	return NOTIFY_OK;
	}

	static struct notifier_block twd_clk_nb = {
	.notifier_call = twd_rate_change,
	};

	static int twd_clk_init(void)
	{
	if (twd_evt && *__this_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
	return clk_notifier_register(twd_clk, &twd_clk_nb);

	return 0;
	}
	core_initcall(twd_clk_init);

	#elif defined (CONFIG_CPU_FREQ)

	#include <linux/cpufreq.h>

	/*
	* Updates clockevent frequency when the cpu frequency changes.
	* Called on the cpu that is changing frequency with interrupts disabled.
	*/
	static void twd_update_frequency(void *data)
	{
	twd_timer_rate = clk_get_rate(twd_clk);

	clockevents_update_freq(*__this_cpu_ptr(twd_evt), twd_timer_rate);
	}

	static int twd_cpufreq_transition(struct notifier_block *nb,
	unsigned long state, void *data)
	{
	struct cpufreq_freqs *freqs = data;

	/*
	* The twd clock events must be reprogrammed to account for the new
	* frequency. The timer is local to a cpu, so cross-call to the
	* changing cpu.
	*/
	if (state == CPUFREQ_POSTCHANGE \|\| state == CPUFREQ_RESUMECHANGE)
	smp_call_function_single(freqs->cpu, twd_update_frequency,
	NULL, 1);

	return NOTIFY_OK;
	}

	static struct notifier_block twd_cpufreq_nb = {
	.notifier_call = twd_cpufreq_transition,
	};

	static int twd_cpufreq_init(void)
	{
	if (twd_evt && *__this_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
	return cpufreq_register_notifier(&twd_cpufreq_nb,
	CPUFREQ_TRANSITION_NOTIFIER);

	return 0;
	}
	core_initcall(twd_cpufreq_init);

	#endif

	static void twd_calibrate_rate(void)
	{
	unsigned long count;
	u64 waitjiffies;

	/*
	* If this is the first time round, we need to work out how fast
	* the timer ticks
	*/
	if (twd_timer_rate == 0) {
	printk(KERN_INFO "Calibrating local timer... ");

	/* Wait for a tick to start */
	waitjiffies = get_jiffies_64() + 1;

	while (get_jiffies_64() < waitjiffies)
	udelay(10);

	/* OK, now the tick has started, let's get the timer going */
	waitjiffies += 5;

	/* enable, no interrupt or reload */
	__raw_writel(0x1, twd_base + TWD_TIMER_CONTROL);

	/* maximum value */
	__raw_writel(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER);

	while (get_jiffies_64() < waitjiffies)
	udelay(10);

	count = __raw_readl(twd_base + TWD_TIMER_COUNTER);

	twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);

	printk("%lu.%02luMHz.\n", twd_timer_rate / 1000000,
	(twd_timer_rate / 10000) % 100);
	}
	}

	static irqreturn_t twd_handler(int irq, void *dev_id)
	{
	struct clock_event_device evt = (struct clock_event_device **)dev_id;

	if (twd_timer_ack()) {
	evt->event_handler(evt);
	return IRQ_HANDLED;
	}

	return IRQ_NONE;
	}

	static void twd_get_clock(struct device_node *np)
	{
	int err;

	if (np)
	twd_clk = of_clk_get(np, 0);
	else
	twd_clk = clk_get_sys("smp_twd", NULL);

	if (IS_ERR(twd_clk)) {
	pr_err("smp_twd: clock not found %d\n", (int) PTR_ERR(twd_clk));
	return;
	}

	err = clk_prepare_enable(twd_clk);
	if (err) {
	pr_err("smp_twd: clock failed to prepare+enable: %d\n", err);
	clk_put(twd_clk);
	return;
	}

	twd_timer_rate = clk_get_rate(twd_clk);
	}

	/*
	* Setup the local clock events for a CPU.
	*/
	static int twd_timer_setup(struct clock_event_device *clk)
	{
	struct clock_event_device **this_cpu_clk;
	int cpu = smp_processor_id();

	/*
	* If the basic setup for this CPU has been done before don't
	* bother with the below.
	*/
	if (per_cpu(percpu_setup_called, cpu)) {
	__raw_writel(0, twd_base + TWD_TIMER_CONTROL);
	clockevents_register_device(*__this_cpu_ptr(twd_evt));
	enable_percpu_irq(clk->irq, 0);
	return 0;
	}
	per_cpu(percpu_setup_called, cpu) = true;

	twd_calibrate_rate();

	/*
	* The following is done once per CPU the first time .setup() is
	* called.
	*/
	__raw_writel(0, twd_base + TWD_TIMER_CONTROL);

	clk->name = "local_timer";
	clk->features = CLOCK_EVT_FEAT_PERIODIC \| CLOCK_EVT_FEAT_ONESHOT \|
	CLOCK_EVT_FEAT_C3STOP;
	clk->rating = 350;
	clk->set_mode = twd_set_mode;
	clk->set_next_event = twd_set_next_event;
	clk->irq = twd_ppi;

	this_cpu_clk = __this_cpu_ptr(twd_evt);
	*this_cpu_clk = clk;

	clockevents_config_and_register(clk, twd_timer_rate,
	0xf, 0xffffffff);
	enable_percpu_irq(clk->irq, 0);

	return 0;
	}

	static struct local_timer_ops twd_lt_ops = {
	.setup = twd_timer_setup,
	.stop = twd_timer_stop,
	};

	static int __init twd_local_timer_common_register(struct device_node *np)
	{
	int err;

	twd_evt = alloc_percpu(struct clock_event_device *);
	if (!twd_evt) {
	err = -ENOMEM;
	goto out_free;
	}

	err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt);
	if (err) {
	pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, err);
	goto out_free;
	}

	err = local_timer_register(&twd_lt_ops);
	if (err)
	goto out_irq;

	twd_get_clock(np);

	return 0;

	out_irq:
	free_percpu_irq(twd_ppi, twd_evt);
	out_free:
	iounmap(twd_base);
	twd_base = NULL;
	free_percpu(twd_evt);

	return err;
	}

	int __init twd_local_timer_register(struct twd_local_timer *tlt)
	{
	if (twd_base \|\| twd_evt)
	return -EBUSY;

	twd_ppi = tlt->res[1].start;

	twd_base = ioremap(tlt->res[0].start, resource_size(&tlt->res[0]));
	if (!twd_base)
	return -ENOMEM;

	return twd_local_timer_common_register(NULL);
	}

	#ifdef CONFIG_OF
	static void __init twd_local_timer_of_register(struct device_node *np)
	{
	int err;

	if (!is_smp() \|\| !setup_max_cpus)
	return;

	twd_ppi = irq_of_parse_and_map(np, 0);
	if (!twd_ppi) {
	err = -EINVAL;
	goto out;
	}

	twd_base = of_iomap(np, 0);
	if (!twd_base) {
	err = -ENOMEM;
	goto out;
	}

	err = twd_local_timer_common_register(np);

	out:
	WARN(err, "twd_local_timer_of_register failed (%d)\n", err);
	}
	CLOCKSOURCE_OF_DECLARE(arm_twd_a9, "arm,cortex-a9-twd-timer", twd_local_timer_of_register);
	CLOCKSOURCE_OF_DECLARE(arm_twd_a5, "arm,cortex-a5-twd-timer", twd_local_timer_of_register);
	CLOCKSOURCE_OF_DECLARE(arm_twd_11mp, "arm,arm11mp-twd-timer", twd_local_timer_of_register);
	#endif