drivers/clocksource/fsl_ftm_timer.c - arm/linux - Git at Google

 /*
  * Freescale FlexTimer Module (FTM) timer driver.
  *
  * Copyright 2014 Freescale Semiconductor, Inc.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * as published by the Free Software Foundation; either version 2
  * of the License, or (at your option) any later version.
  */

 #include <linux/clk.h>
 #include <linux/clockchips.h>
 #include <linux/clocksource.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/sched_clock.h>
 #include <linux/slab.h>

 #define FTM_SC		0x00
 #define FTM_SC_CLK_SHIFT	3
 #define FTM_SC_CLK_MASK	(0x3 << FTM_SC_CLK_SHIFT)
 #define FTM_SC_CLK(c)	((c) << FTM_SC_CLK_SHIFT)
 #define FTM_SC_PS_MASK	0x7
 #define FTM_SC_TOIE	BIT(6)
 #define FTM_SC_TOF	BIT(7)

 #define FTM_CNT		0x04
 #define FTM_MOD		0x08
 #define FTM_CNTIN	0x4C

 #define FTM_PS_MAX	7

 struct ftm_clock_device {
 	void __iomem *clksrc_base;
 	void __iomem *clkevt_base;
 	unsigned long periodic_cyc;
 	unsigned long ps;
 	bool big_endian;
 };

 static struct ftm_clock_device *priv;

 static inline u32 ftm_readl(void __iomem *addr)
 {
 	if (priv->big_endian)
 		return ioread32be(addr);
 	else
 		return ioread32(addr);
 }

 static inline void ftm_writel(u32 val, void __iomem *addr)
 {
 	if (priv->big_endian)
 		iowrite32be(val, addr);
 	else
 		iowrite32(val, addr);
 }

 static inline void ftm_counter_enable(void __iomem *base)
 {
 	u32 val;

 	/* select and enable counter clock source */
 	val = ftm_readl(base + FTM_SC);
 	val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK);
 	val |= priv->ps | FTM_SC_CLK(1);
 	ftm_writel(val, base + FTM_SC);
 }

 static inline void ftm_counter_disable(void __iomem *base)
 {
 	u32 val;

 	/* disable counter clock source */
 	val = ftm_readl(base + FTM_SC);
 	val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK);
 	ftm_writel(val, base + FTM_SC);
 }

 static inline void ftm_irq_acknowledge(void __iomem *base)
 {
 	u32 val;

 	val = ftm_readl(base + FTM_SC);
 	val &= ~FTM_SC_TOF;
 	ftm_writel(val, base + FTM_SC);
 }

 static inline void ftm_irq_enable(void __iomem *base)
 {
 	u32 val;

 	val = ftm_readl(base + FTM_SC);
 	val |= FTM_SC_TOIE;
 	ftm_writel(val, base + FTM_SC);
 }

 static inline void ftm_irq_disable(void __iomem *base)
 {
 	u32 val;

 	val = ftm_readl(base + FTM_SC);
 	val &= ~FTM_SC_TOIE;
 	ftm_writel(val, base + FTM_SC);
 }

 static inline void ftm_reset_counter(void __iomem *base)
 {
 	/*
 	 * The CNT register contains the FTM counter value.
 	 * Reset clears the CNT register. Writing any value to COUNT
 	 * updates the counter with its initial value, CNTIN.
 	 */
 	ftm_writel(0x00, base + FTM_CNT);
 }

 static u64 notrace ftm_read_sched_clock(void)
 {
 	return ftm_readl(priv->clksrc_base + FTM_CNT);
 }

 static int ftm_set_next_event(unsigned long delta,
 				struct clock_event_device *unused)
 {
 	/*
 	 * The CNNIN and MOD are all double buffer registers, writing
 	 * to the MOD register latches the value into a buffer. The MOD
 	 * register is updated with the value of its write buffer with
 	 * the following scenario:
 	 * a, the counter source clock is diabled.
 	 */
 	ftm_counter_disable(priv->clkevt_base);

 	/* Force the value of CNTIN to be loaded into the FTM counter */
 	ftm_reset_counter(priv->clkevt_base);

 	/*
 	 * The counter increments until the value of MOD is reached,
 	 * at which point the counter is reloaded with the value of CNTIN.
 	 * The TOF (the overflow flag) bit is set when the FTM counter
 	 * changes from MOD to CNTIN. So we should using the delta - 1.
 	 */
 	ftm_writel(delta - 1, priv->clkevt_base + FTM_MOD);

 	ftm_counter_enable(priv->clkevt_base);

 	ftm_irq_enable(priv->clkevt_base);

 	return 0;
 }

 static int ftm_set_oneshot(struct clock_event_device *evt)
 {
 	ftm_counter_disable(priv->clkevt_base);
 	return 0;
 }

 static int ftm_set_periodic(struct clock_event_device *evt)
 {
 	ftm_set_next_event(priv->periodic_cyc, evt);
 	return 0;
 }

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

 	ftm_irq_acknowledge(priv->clkevt_base);

 	if (likely(clockevent_state_oneshot(evt))) {
 		ftm_irq_disable(priv->clkevt_base);
 		ftm_counter_disable(priv->clkevt_base);
 	}

 	evt->event_handler(evt);

 	return IRQ_HANDLED;
 }

 static struct clock_event_device ftm_clockevent = {
 	.name			= "Freescale ftm timer",
 	.features		= CLOCK_EVT_FEAT_PERIODIC |
 				  CLOCK_EVT_FEAT_ONESHOT,
 	.set_state_periodic	= ftm_set_periodic,
 	.set_state_oneshot	= ftm_set_oneshot,
 	.set_next_event		= ftm_set_next_event,
 	.rating			= 300,
 };

 static struct irqaction ftm_timer_irq = {
 	.name		= "Freescale ftm timer",
 	.flags		= IRQF_TIMER | IRQF_IRQPOLL,
 	.handler	= ftm_evt_interrupt,
 	.dev_id		= &ftm_clockevent,
 };

 static int __init ftm_clockevent_init(unsigned long freq, int irq)
 {
 	int err;

 	ftm_writel(0x00, priv->clkevt_base + FTM_CNTIN);
 	ftm_writel(~0UL, priv->clkevt_base + FTM_MOD);

 	ftm_reset_counter(priv->clkevt_base);

 	err = setup_irq(irq, &ftm_timer_irq);
 	if (err) {
 		pr_err("ftm: setup irq failed: %d\n", err);
 		return err;
 	}

 	ftm_clockevent.cpumask = cpumask_of(0);
 	ftm_clockevent.irq = irq;

 	clockevents_config_and_register(&ftm_clockevent,
 					freq / (1 << priv->ps),
 					1, 0xffff);

 	ftm_counter_enable(priv->clkevt_base);

 	return 0;
 }

 static int __init ftm_clocksource_init(unsigned long freq)
 {
 	int err;

 	ftm_writel(0x00, priv->clksrc_base + FTM_CNTIN);
 	ftm_writel(~0UL, priv->clksrc_base + FTM_MOD);

 	ftm_reset_counter(priv->clksrc_base);

 	sched_clock_register(ftm_read_sched_clock, 16, freq / (1 << priv->ps));
 	err = clocksource_mmio_init(priv->clksrc_base + FTM_CNT, "fsl-ftm",
 				    freq / (1 << priv->ps), 300, 16,
 				    clocksource_mmio_readl_up);
 	if (err) {
 		pr_err("ftm: init clock source mmio failed: %d\n", err);
 		return err;
 	}

 	ftm_counter_enable(priv->clksrc_base);

 	return 0;
 }

 static int __init __ftm_clk_init(struct device_node *np, char *cnt_name,
 				 char *ftm_name)
 {
 	struct clk *clk;
 	int err;

 	clk = of_clk_get_by_name(np, cnt_name);
 	if (IS_ERR(clk)) {
 		pr_err("ftm: Cannot get \"%s\": %ld\n", cnt_name, PTR_ERR(clk));
 		return PTR_ERR(clk);
 	}
 	err = clk_prepare_enable(clk);
 	if (err) {
 		pr_err("ftm: clock failed to prepare+enable \"%s\": %d\n",
 			cnt_name, err);
 		return err;
 	}

 	clk = of_clk_get_by_name(np, ftm_name);
 	if (IS_ERR(clk)) {
 		pr_err("ftm: Cannot get \"%s\": %ld\n", ftm_name, PTR_ERR(clk));
 		return PTR_ERR(clk);
 	}
 	err = clk_prepare_enable(clk);
 	if (err)
 		pr_err("ftm: clock failed to prepare+enable \"%s\": %d\n",
 			ftm_name, err);

 	return clk_get_rate(clk);
 }

 static unsigned long __init ftm_clk_init(struct device_node *np)
 {
 	unsigned long freq;

 	freq = __ftm_clk_init(np, "ftm-evt-counter-en", "ftm-evt");
 	if (freq <= 0)
 		return 0;

 	freq = __ftm_clk_init(np, "ftm-src-counter-en", "ftm-src");
 	if (freq <= 0)
 		return 0;

 	return freq;
 }

 static int __init ftm_calc_closest_round_cyc(unsigned long freq)
 {
 	priv->ps = 0;

 	/* The counter register is only using the lower 16 bits, and
 	 * if the 'freq' value is to big here, then the periodic_cyc
 	 * may exceed 0xFFFF.
 	 */
 	do {
 		priv->periodic_cyc = DIV_ROUND_CLOSEST(freq,
 						HZ * (1 << priv->ps++));
 	} while (priv->periodic_cyc > 0xFFFF);

 	if (priv->ps > FTM_PS_MAX) {
 		pr_err("ftm: the prescaler is %lu > %d\n",
 				priv->ps, FTM_PS_MAX);
 		return -EINVAL;
 	}

 	return 0;
 }

 static void __init ftm_timer_init(struct device_node *np)
 {
 	unsigned long freq;
 	int irq;

 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return;

 	priv->clkevt_base = of_iomap(np, 0);
 	if (!priv->clkevt_base) {
 		pr_err("ftm: unable to map event timer registers\n");
 		goto err;
 	}

 	priv->clksrc_base = of_iomap(np, 1);
 	if (!priv->clksrc_base) {
 		pr_err("ftm: unable to map source timer registers\n");
 		goto err;
 	}

 	irq = irq_of_parse_and_map(np, 0);
 	if (irq <= 0) {
 		pr_err("ftm: unable to get IRQ from DT, %d\n", irq);
 		goto err;
 	}

 	priv->big_endian = of_property_read_bool(np, "big-endian");

 	freq = ftm_clk_init(np);
 	if (!freq)
 		goto err;

 	if (ftm_calc_closest_round_cyc(freq))
 		goto err;

 	if (ftm_clocksource_init(freq))
 		goto err;

 	if (ftm_clockevent_init(freq, irq))
 		goto err;

 	return;

 err:
 	kfree(priv);
 }
 CLOCKSOURCE_OF_DECLARE(flextimer, "fsl,ftm-timer", ftm_timer_init);
	/*
	* Freescale FlexTimer Module (FTM) timer driver.
	*
	* Copyright 2014 Freescale Semiconductor, Inc.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version 2
	* of the License, or (at your option) any later version.
	*/

	#include <linux/clk.h>
	#include <linux/clockchips.h>
	#include <linux/clocksource.h>
	#include <linux/err.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/sched_clock.h>
	#include <linux/slab.h>

	#define FTM_SC 0x00
	#define FTM_SC_CLK_SHIFT 3
	#define FTM_SC_CLK_MASK (0x3 << FTM_SC_CLK_SHIFT)
	#define FTM_SC_CLK(c) ((c) << FTM_SC_CLK_SHIFT)
	#define FTM_SC_PS_MASK 0x7
	#define FTM_SC_TOIE BIT(6)
	#define FTM_SC_TOF BIT(7)

	#define FTM_CNT 0x04
	#define FTM_MOD 0x08
	#define FTM_CNTIN 0x4C

	#define FTM_PS_MAX 7

	struct ftm_clock_device {
	void __iomem *clksrc_base;
	void __iomem *clkevt_base;
	unsigned long periodic_cyc;
	unsigned long ps;
	bool big_endian;
	};

	static struct ftm_clock_device *priv;

	static inline u32 ftm_readl(void __iomem *addr)
	{
	if (priv->big_endian)
	return ioread32be(addr);
	else
	return ioread32(addr);
	}

	static inline void ftm_writel(u32 val, void __iomem *addr)
	{
	if (priv->big_endian)
	iowrite32be(val, addr);
	else
	iowrite32(val, addr);
	}

	static inline void ftm_counter_enable(void __iomem *base)
	{
	u32 val;

	/* select and enable counter clock source */
	val = ftm_readl(base + FTM_SC);
	val &= ~(FTM_SC_PS_MASK \| FTM_SC_CLK_MASK);
	val \|= priv->ps \| FTM_SC_CLK(1);
	ftm_writel(val, base + FTM_SC);
	}

	static inline void ftm_counter_disable(void __iomem *base)
	{
	u32 val;

	/* disable counter clock source */
	val = ftm_readl(base + FTM_SC);
	val &= ~(FTM_SC_PS_MASK \| FTM_SC_CLK_MASK);
	ftm_writel(val, base + FTM_SC);
	}

	static inline void ftm_irq_acknowledge(void __iomem *base)
	{
	u32 val;

	val = ftm_readl(base + FTM_SC);
	val &= ~FTM_SC_TOF;
	ftm_writel(val, base + FTM_SC);
	}

	static inline void ftm_irq_enable(void __iomem *base)
	{
	u32 val;

	val = ftm_readl(base + FTM_SC);
	val \|= FTM_SC_TOIE;
	ftm_writel(val, base + FTM_SC);
	}

	static inline void ftm_irq_disable(void __iomem *base)
	{
	u32 val;

	val = ftm_readl(base + FTM_SC);
	val &= ~FTM_SC_TOIE;
	ftm_writel(val, base + FTM_SC);
	}

	static inline void ftm_reset_counter(void __iomem *base)
	{
	/*
	* The CNT register contains the FTM counter value.
	* Reset clears the CNT register. Writing any value to COUNT
	* updates the counter with its initial value, CNTIN.
	*/
	ftm_writel(0x00, base + FTM_CNT);
	}

	static u64 notrace ftm_read_sched_clock(void)
	{
	return ftm_readl(priv->clksrc_base + FTM_CNT);
	}

	static int ftm_set_next_event(unsigned long delta,
	struct clock_event_device *unused)
	{
	/*
	* The CNNIN and MOD are all double buffer registers, writing
	* to the MOD register latches the value into a buffer. The MOD
	* register is updated with the value of its write buffer with
	* the following scenario:
	* a, the counter source clock is diabled.
	*/
	ftm_counter_disable(priv->clkevt_base);

	/* Force the value of CNTIN to be loaded into the FTM counter */
	ftm_reset_counter(priv->clkevt_base);

	/*
	* The counter increments until the value of MOD is reached,
	* at which point the counter is reloaded with the value of CNTIN.
	* The TOF (the overflow flag) bit is set when the FTM counter
	* changes from MOD to CNTIN. So we should using the delta - 1.
	*/
	ftm_writel(delta - 1, priv->clkevt_base + FTM_MOD);

	ftm_counter_enable(priv->clkevt_base);

	ftm_irq_enable(priv->clkevt_base);

	return 0;
	}

	static int ftm_set_oneshot(struct clock_event_device *evt)
	{
	ftm_counter_disable(priv->clkevt_base);
	return 0;
	}

	static int ftm_set_periodic(struct clock_event_device *evt)
	{
	ftm_set_next_event(priv->periodic_cyc, evt);
	return 0;
	}

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

	ftm_irq_acknowledge(priv->clkevt_base);

	if (likely(clockevent_state_oneshot(evt))) {
	ftm_irq_disable(priv->clkevt_base);
	ftm_counter_disable(priv->clkevt_base);
	}

	evt->event_handler(evt);

	return IRQ_HANDLED;
	}

	static struct clock_event_device ftm_clockevent = {
	.name = "Freescale ftm timer",
	.features = CLOCK_EVT_FEAT_PERIODIC \|
	CLOCK_EVT_FEAT_ONESHOT,
	.set_state_periodic = ftm_set_periodic,
	.set_state_oneshot = ftm_set_oneshot,
	.set_next_event = ftm_set_next_event,
	.rating = 300,
	};

	static struct irqaction ftm_timer_irq = {
	.name = "Freescale ftm timer",
	.flags = IRQF_TIMER \| IRQF_IRQPOLL,
	.handler = ftm_evt_interrupt,
	.dev_id = &ftm_clockevent,
	};

	static int __init ftm_clockevent_init(unsigned long freq, int irq)
	{
	int err;

	ftm_writel(0x00, priv->clkevt_base + FTM_CNTIN);
	ftm_writel(~0UL, priv->clkevt_base + FTM_MOD);

	ftm_reset_counter(priv->clkevt_base);

	err = setup_irq(irq, &ftm_timer_irq);
	if (err) {
	pr_err("ftm: setup irq failed: %d\n", err);
	return err;
	}

	ftm_clockevent.cpumask = cpumask_of(0);
	ftm_clockevent.irq = irq;

	clockevents_config_and_register(&ftm_clockevent,
	freq / (1 << priv->ps),
	1, 0xffff);

	ftm_counter_enable(priv->clkevt_base);

	return 0;
	}

	static int __init ftm_clocksource_init(unsigned long freq)
	{
	int err;

	ftm_writel(0x00, priv->clksrc_base + FTM_CNTIN);
	ftm_writel(~0UL, priv->clksrc_base + FTM_MOD);

	ftm_reset_counter(priv->clksrc_base);

	sched_clock_register(ftm_read_sched_clock, 16, freq / (1 << priv->ps));
	err = clocksource_mmio_init(priv->clksrc_base + FTM_CNT, "fsl-ftm",
	freq / (1 << priv->ps), 300, 16,
	clocksource_mmio_readl_up);
	if (err) {
	pr_err("ftm: init clock source mmio failed: %d\n", err);
	return err;
	}

	ftm_counter_enable(priv->clksrc_base);

	return 0;
	}

	static int __init __ftm_clk_init(struct device_node np, char cnt_name,
	char *ftm_name)
	{
	struct clk *clk;
	int err;

	clk = of_clk_get_by_name(np, cnt_name);
	if (IS_ERR(clk)) {
	pr_err("ftm: Cannot get \"%s\": %ld\n", cnt_name, PTR_ERR(clk));
	return PTR_ERR(clk);
	}
	err = clk_prepare_enable(clk);
	if (err) {
	pr_err("ftm: clock failed to prepare+enable \"%s\": %d\n",
	cnt_name, err);
	return err;
	}

	clk = of_clk_get_by_name(np, ftm_name);
	if (IS_ERR(clk)) {
	pr_err("ftm: Cannot get \"%s\": %ld\n", ftm_name, PTR_ERR(clk));
	return PTR_ERR(clk);
	}
	err = clk_prepare_enable(clk);
	if (err)
	pr_err("ftm: clock failed to prepare+enable \"%s\": %d\n",
	ftm_name, err);

	return clk_get_rate(clk);
	}

	static unsigned long __init ftm_clk_init(struct device_node *np)
	{
	unsigned long freq;

	freq = __ftm_clk_init(np, "ftm-evt-counter-en", "ftm-evt");
	if (freq <= 0)
	return 0;

	freq = __ftm_clk_init(np, "ftm-src-counter-en", "ftm-src");
	if (freq <= 0)
	return 0;

	return freq;
	}

	static int __init ftm_calc_closest_round_cyc(unsigned long freq)
	{
	priv->ps = 0;

	/* The counter register is only using the lower 16 bits, and
	* if the 'freq' value is to big here, then the periodic_cyc
	* may exceed 0xFFFF.
	*/
	do {
	priv->periodic_cyc = DIV_ROUND_CLOSEST(freq,
	HZ * (1 << priv->ps++));
	} while (priv->periodic_cyc > 0xFFFF);

	if (priv->ps > FTM_PS_MAX) {
	pr_err("ftm: the prescaler is %lu > %d\n",
	priv->ps, FTM_PS_MAX);
	return -EINVAL;
	}

	return 0;
	}

	static void __init ftm_timer_init(struct device_node *np)
	{
	unsigned long freq;
	int irq;

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv)
	return;

	priv->clkevt_base = of_iomap(np, 0);
	if (!priv->clkevt_base) {
	pr_err("ftm: unable to map event timer registers\n");
	goto err;
	}

	priv->clksrc_base = of_iomap(np, 1);
	if (!priv->clksrc_base) {
	pr_err("ftm: unable to map source timer registers\n");
	goto err;
	}

	irq = irq_of_parse_and_map(np, 0);
	if (irq <= 0) {
	pr_err("ftm: unable to get IRQ from DT, %d\n", irq);
	goto err;
	}

	priv->big_endian = of_property_read_bool(np, "big-endian");

	freq = ftm_clk_init(np);
	if (!freq)
	goto err;

	if (ftm_calc_closest_round_cyc(freq))
	goto err;

	if (ftm_clocksource_init(freq))
	goto err;

	if (ftm_clockevent_init(freq, irq))
	goto err;

	return;

	err:
	kfree(priv);
	}
	CLOCKSOURCE_OF_DECLARE(flextimer, "fsl,ftm-timer", ftm_timer_init);