drivers/clocksource/qcom-timer.c - linux - Git at Google

 /*
  *
  * Copyright (C) 2007 Google, Inc.
  * Copyright (c) 2009-2012,2014, The Linux Foundation. All rights reserved.
  *
  * This software is licensed under the terms of the GNU General Public
  * License version 2, as published by the Free Software Foundation, and
  * may be copied, distributed, and modified under those terms.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  */

 #include <linux/clocksource.h>
 #include <linux/clockchips.h>
 #include <linux/cpu.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/sched_clock.h>

 #include <asm/delay.h>

 #define TIMER_MATCH_VAL			0x0000
 #define TIMER_COUNT_VAL			0x0004
 #define TIMER_ENABLE			0x0008
 #define TIMER_ENABLE_CLR_ON_MATCH_EN	BIT(1)
 #define TIMER_ENABLE_EN			BIT(0)
 #define TIMER_CLEAR			0x000C
 #define DGT_CLK_CTL			0x10
 #define DGT_CLK_CTL_DIV_4		0x3
 #define TIMER_STS_GPT0_CLR_PEND		BIT(10)

 #define GPT_HZ 32768

 static void __iomem *event_base;
 static void __iomem *sts_base;

 static irqreturn_t msm_timer_interrupt(int irq, void *dev_id)
 {
 	struct clock_event_device *evt = dev_id;
 	/* Stop the timer tick */
 	if (clockevent_state_oneshot(evt)) {
 		u32 ctrl = readl_relaxed(event_base + TIMER_ENABLE);
 		ctrl &= ~TIMER_ENABLE_EN;
 		writel_relaxed(ctrl, event_base + TIMER_ENABLE);
 	}
 	evt->event_handler(evt);
 	return IRQ_HANDLED;
 }

 static int msm_timer_set_next_event(unsigned long cycles,
 				    struct clock_event_device *evt)
 {
 	u32 ctrl = readl_relaxed(event_base + TIMER_ENABLE);

 	ctrl &= ~TIMER_ENABLE_EN;
 	writel_relaxed(ctrl, event_base + TIMER_ENABLE);

 	writel_relaxed(ctrl, event_base + TIMER_CLEAR);
 	writel_relaxed(cycles, event_base + TIMER_MATCH_VAL);

 	if (sts_base)
 		while (readl_relaxed(sts_base) & TIMER_STS_GPT0_CLR_PEND)
 			cpu_relax();

 	writel_relaxed(ctrl | TIMER_ENABLE_EN, event_base + TIMER_ENABLE);
 	return 0;
 }

 static int msm_timer_shutdown(struct clock_event_device *evt)
 {
 	u32 ctrl;

 	ctrl = readl_relaxed(event_base + TIMER_ENABLE);
 	ctrl &= ~(TIMER_ENABLE_EN | TIMER_ENABLE_CLR_ON_MATCH_EN);
 	writel_relaxed(ctrl, event_base + TIMER_ENABLE);
 	return 0;
 }

 static struct clock_event_device __percpu *msm_evt;

 static void __iomem *source_base;

 static notrace cycle_t msm_read_timer_count(struct clocksource *cs)
 {
 	return readl_relaxed(source_base + TIMER_COUNT_VAL);
 }

 static struct clocksource msm_clocksource = {
 	.name	= "dg_timer",
 	.rating	= 300,
 	.read	= msm_read_timer_count,
 	.mask	= CLOCKSOURCE_MASK(32),
 	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
 };

 static int msm_timer_irq;
 static int msm_timer_has_ppi;

 static int msm_local_timer_setup(struct clock_event_device *evt)
 {
 	int cpu = smp_processor_id();
 	int err;

 	evt->irq = msm_timer_irq;
 	evt->name = "msm_timer";
 	evt->features = CLOCK_EVT_FEAT_ONESHOT;
 	evt->rating = 200;
 	evt->set_state_shutdown = msm_timer_shutdown;
 	evt->set_state_oneshot = msm_timer_shutdown;
 	evt->tick_resume = msm_timer_shutdown;
 	evt->set_next_event = msm_timer_set_next_event;
 	evt->cpumask = cpumask_of(cpu);

 	clockevents_config_and_register(evt, GPT_HZ, 4, 0xffffffff);

 	if (msm_timer_has_ppi) {
 		enable_percpu_irq(evt->irq, IRQ_TYPE_EDGE_RISING);
 	} else {
 		err = request_irq(evt->irq, msm_timer_interrupt,
 				IRQF_TIMER | IRQF_NOBALANCING |
 				IRQF_TRIGGER_RISING, "gp_timer", evt);
 		if (err)
 			pr_err("request_irq failed\n");
 	}

 	return 0;
 }

 static void msm_local_timer_stop(struct clock_event_device *evt)
 {
 	evt->set_state_shutdown(evt);
 	disable_percpu_irq(evt->irq);
 }

 static int msm_timer_cpu_notify(struct notifier_block *self,
 					   unsigned long action, void *hcpu)
 {
 	/*
 	 * Grab cpu pointer in each case to avoid spurious
 	 * preemptible warnings
 	 */
 	switch (action & ~CPU_TASKS_FROZEN) {
 	case CPU_STARTING:
 		msm_local_timer_setup(this_cpu_ptr(msm_evt));
 		break;
 	case CPU_DYING:
 		msm_local_timer_stop(this_cpu_ptr(msm_evt));
 		break;
 	}

 	return NOTIFY_OK;
 }

 static struct notifier_block msm_timer_cpu_nb = {
 	.notifier_call = msm_timer_cpu_notify,
 };

 static u64 notrace msm_sched_clock_read(void)
 {
 	return msm_clocksource.read(&msm_clocksource);
 }

 static unsigned long msm_read_current_timer(void)
 {
 	return msm_clocksource.read(&msm_clocksource);
 }

 static struct delay_timer msm_delay_timer = {
 	.read_current_timer = msm_read_current_timer,
 };

 static void __init msm_timer_init(u32 dgt_hz, int sched_bits, int irq,
 				  bool percpu)
 {
 	struct clocksource *cs = &msm_clocksource;
 	int res = 0;

 	msm_timer_irq = irq;
 	msm_timer_has_ppi = percpu;

 	msm_evt = alloc_percpu(struct clock_event_device);
 	if (!msm_evt) {
 		pr_err("memory allocation failed for clockevents\n");
 		goto err;
 	}

 	if (percpu)
 		res = request_percpu_irq(irq, msm_timer_interrupt,
 					 "gp_timer", msm_evt);

 	if (res) {
 		pr_err("request_percpu_irq failed\n");
 	} else {
 		res = register_cpu_notifier(&msm_timer_cpu_nb);
 		if (res) {
 			free_percpu_irq(irq, msm_evt);
 			goto err;
 		}

 		/* Immediately configure the timer on the boot CPU */
 		msm_local_timer_setup(raw_cpu_ptr(msm_evt));
 	}

 err:
 	writel_relaxed(TIMER_ENABLE_EN, source_base + TIMER_ENABLE);
 	res = clocksource_register_hz(cs, dgt_hz);
 	if (res)
 		pr_err("clocksource_register failed\n");
 	sched_clock_register(msm_sched_clock_read, sched_bits, dgt_hz);
 	msm_delay_timer.freq = dgt_hz;
 	register_current_timer_delay(&msm_delay_timer);
 }

 static void __init msm_dt_timer_init(struct device_node *np)
 {
 	u32 freq;
 	int irq;
 	struct resource res;
 	u32 percpu_offset;
 	void __iomem *base;
 	void __iomem *cpu0_base;

 	base = of_iomap(np, 0);
 	if (!base) {
 		pr_err("Failed to map event base\n");
 		return;
 	}

 	/* We use GPT0 for the clockevent */
 	irq = irq_of_parse_and_map(np, 1);
 	if (irq <= 0) {
 		pr_err("Can't get irq\n");
 		return;
 	}

 	/* We use CPU0's DGT for the clocksource */
 	if (of_property_read_u32(np, "cpu-offset", &percpu_offset))
 		percpu_offset = 0;

 	if (of_address_to_resource(np, 0, &res)) {
 		pr_err("Failed to parse DGT resource\n");
 		return;
 	}

 	cpu0_base = ioremap(res.start + percpu_offset, resource_size(&res));
 	if (!cpu0_base) {
 		pr_err("Failed to map source base\n");
 		return;
 	}

 	if (of_property_read_u32(np, "clock-frequency", &freq)) {
 		pr_err("Unknown frequency\n");
 		return;
 	}

 	event_base = base + 0x4;
 	sts_base = base + 0x88;
 	source_base = cpu0_base + 0x24;
 	freq /= 4;
 	writel_relaxed(DGT_CLK_CTL_DIV_4, source_base + DGT_CLK_CTL);

 	msm_timer_init(freq, 32, irq, !!percpu_offset);
 }
 CLOCKSOURCE_OF_DECLARE(kpss_timer, "qcom,kpss-timer", msm_dt_timer_init);
 CLOCKSOURCE_OF_DECLARE(scss_timer, "qcom,scss-timer", msm_dt_timer_init);
	/*
	*
	* Copyright (C) 2007 Google, Inc.
	* Copyright (c) 2009-2012,2014, The Linux Foundation. All rights reserved.
	*
	* This software is licensed under the terms of the GNU General Public
	* License version 2, as published by the Free Software Foundation, and
	* may be copied, distributed, and modified under those terms.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	*/

	#include <linux/clocksource.h>
	#include <linux/clockchips.h>
	#include <linux/cpu.h>
	#include <linux/init.h>
	#include <linux/interrupt.h>
	#include <linux/irq.h>
	#include <linux/io.h>
	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/sched_clock.h>

	#include <asm/delay.h>

	#define TIMER_MATCH_VAL 0x0000
	#define TIMER_COUNT_VAL 0x0004
	#define TIMER_ENABLE 0x0008
	#define TIMER_ENABLE_CLR_ON_MATCH_EN BIT(1)
	#define TIMER_ENABLE_EN BIT(0)
	#define TIMER_CLEAR 0x000C
	#define DGT_CLK_CTL 0x10
	#define DGT_CLK_CTL_DIV_4 0x3
	#define TIMER_STS_GPT0_CLR_PEND BIT(10)

	#define GPT_HZ 32768

	static void __iomem *event_base;
	static void __iomem *sts_base;

	static irqreturn_t msm_timer_interrupt(int irq, void *dev_id)
	{
	struct clock_event_device *evt = dev_id;
	/* Stop the timer tick */
	if (clockevent_state_oneshot(evt)) {
	u32 ctrl = readl_relaxed(event_base + TIMER_ENABLE);
	ctrl &= ~TIMER_ENABLE_EN;
	writel_relaxed(ctrl, event_base + TIMER_ENABLE);
	}
	evt->event_handler(evt);
	return IRQ_HANDLED;
	}

	static int msm_timer_set_next_event(unsigned long cycles,
	struct clock_event_device *evt)
	{
	u32 ctrl = readl_relaxed(event_base + TIMER_ENABLE);

	ctrl &= ~TIMER_ENABLE_EN;
	writel_relaxed(ctrl, event_base + TIMER_ENABLE);

	writel_relaxed(ctrl, event_base + TIMER_CLEAR);
	writel_relaxed(cycles, event_base + TIMER_MATCH_VAL);

	if (sts_base)
	while (readl_relaxed(sts_base) & TIMER_STS_GPT0_CLR_PEND)
	cpu_relax();

	writel_relaxed(ctrl \| TIMER_ENABLE_EN, event_base + TIMER_ENABLE);
	return 0;
	}

	static int msm_timer_shutdown(struct clock_event_device *evt)
	{
	u32 ctrl;

	ctrl = readl_relaxed(event_base + TIMER_ENABLE);
	ctrl &= ~(TIMER_ENABLE_EN \| TIMER_ENABLE_CLR_ON_MATCH_EN);
	writel_relaxed(ctrl, event_base + TIMER_ENABLE);
	return 0;
	}

	static struct clock_event_device __percpu *msm_evt;

	static void __iomem *source_base;

	static notrace cycle_t msm_read_timer_count(struct clocksource *cs)
	{
	return readl_relaxed(source_base + TIMER_COUNT_VAL);
	}

	static struct clocksource msm_clocksource = {
	.name = "dg_timer",
	.rating = 300,
	.read = msm_read_timer_count,
	.mask = CLOCKSOURCE_MASK(32),
	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
	};

	static int msm_timer_irq;
	static int msm_timer_has_ppi;

	static int msm_local_timer_setup(struct clock_event_device *evt)
	{
	int cpu = smp_processor_id();
	int err;

	evt->irq = msm_timer_irq;
	evt->name = "msm_timer";
	evt->features = CLOCK_EVT_FEAT_ONESHOT;
	evt->rating = 200;
	evt->set_state_shutdown = msm_timer_shutdown;
	evt->set_state_oneshot = msm_timer_shutdown;
	evt->tick_resume = msm_timer_shutdown;
	evt->set_next_event = msm_timer_set_next_event;
	evt->cpumask = cpumask_of(cpu);

	clockevents_config_and_register(evt, GPT_HZ, 4, 0xffffffff);

	if (msm_timer_has_ppi) {
	enable_percpu_irq(evt->irq, IRQ_TYPE_EDGE_RISING);
	} else {
	err = request_irq(evt->irq, msm_timer_interrupt,
	IRQF_TIMER \| IRQF_NOBALANCING \|
	IRQF_TRIGGER_RISING, "gp_timer", evt);
	if (err)
	pr_err("request_irq failed\n");
	}

	return 0;
	}

	static void msm_local_timer_stop(struct clock_event_device *evt)
	{
	evt->set_state_shutdown(evt);
	disable_percpu_irq(evt->irq);
	}

	static int msm_timer_cpu_notify(struct notifier_block *self,
	unsigned long action, void *hcpu)
	{
	/*
	* Grab cpu pointer in each case to avoid spurious
	* preemptible warnings
	*/
	switch (action & ~CPU_TASKS_FROZEN) {
	case CPU_STARTING:
	msm_local_timer_setup(this_cpu_ptr(msm_evt));
	break;
	case CPU_DYING:
	msm_local_timer_stop(this_cpu_ptr(msm_evt));
	break;
	}

	return NOTIFY_OK;
	}

	static struct notifier_block msm_timer_cpu_nb = {
	.notifier_call = msm_timer_cpu_notify,
	};

	static u64 notrace msm_sched_clock_read(void)
	{
	return msm_clocksource.read(&msm_clocksource);
	}

	static unsigned long msm_read_current_timer(void)
	{
	return msm_clocksource.read(&msm_clocksource);
	}

	static struct delay_timer msm_delay_timer = {
	.read_current_timer = msm_read_current_timer,
	};

	static void __init msm_timer_init(u32 dgt_hz, int sched_bits, int irq,
	bool percpu)
	{
	struct clocksource *cs = &msm_clocksource;
	int res = 0;

	msm_timer_irq = irq;
	msm_timer_has_ppi = percpu;

	msm_evt = alloc_percpu(struct clock_event_device);
	if (!msm_evt) {
	pr_err("memory allocation failed for clockevents\n");
	goto err;
	}

	if (percpu)
	res = request_percpu_irq(irq, msm_timer_interrupt,
	"gp_timer", msm_evt);

	if (res) {
	pr_err("request_percpu_irq failed\n");
	} else {
	res = register_cpu_notifier(&msm_timer_cpu_nb);
	if (res) {
	free_percpu_irq(irq, msm_evt);
	goto err;
	}

	/* Immediately configure the timer on the boot CPU */
	msm_local_timer_setup(raw_cpu_ptr(msm_evt));
	}

	err:
	writel_relaxed(TIMER_ENABLE_EN, source_base + TIMER_ENABLE);
	res = clocksource_register_hz(cs, dgt_hz);
	if (res)
	pr_err("clocksource_register failed\n");
	sched_clock_register(msm_sched_clock_read, sched_bits, dgt_hz);
	msm_delay_timer.freq = dgt_hz;
	register_current_timer_delay(&msm_delay_timer);
	}

	static void __init msm_dt_timer_init(struct device_node *np)
	{
	u32 freq;
	int irq;
	struct resource res;
	u32 percpu_offset;
	void __iomem *base;
	void __iomem *cpu0_base;

	base = of_iomap(np, 0);
	if (!base) {
	pr_err("Failed to map event base\n");
	return;
	}

	/* We use GPT0 for the clockevent */
	irq = irq_of_parse_and_map(np, 1);
	if (irq <= 0) {
	pr_err("Can't get irq\n");
	return;
	}

	/* We use CPU0's DGT for the clocksource */
	if (of_property_read_u32(np, "cpu-offset", &percpu_offset))
	percpu_offset = 0;

	if (of_address_to_resource(np, 0, &res)) {
	pr_err("Failed to parse DGT resource\n");
	return;
	}

	cpu0_base = ioremap(res.start + percpu_offset, resource_size(&res));
	if (!cpu0_base) {
	pr_err("Failed to map source base\n");
	return;
	}

	if (of_property_read_u32(np, "clock-frequency", &freq)) {
	pr_err("Unknown frequency\n");
	return;
	}

	event_base = base + 0x4;
	sts_base = base + 0x88;
	source_base = cpu0_base + 0x24;
	freq /= 4;
	writel_relaxed(DGT_CLK_CTL_DIV_4, source_base + DGT_CLK_CTL);

	msm_timer_init(freq, 32, irq, !!percpu_offset);
	}
	CLOCKSOURCE_OF_DECLARE(kpss_timer, "qcom,kpss-timer", msm_dt_timer_init);
	CLOCKSOURCE_OF_DECLARE(scss_timer, "qcom,scss-timer", msm_dt_timer_init);