src/kernel/linux/v4.19/drivers/clocksource/timer-fttmr010.c - T800 - Gitiles

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Faraday Technology FTTMR010 timer driver
  * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
  *
  * Based on a rewrite of arch/arm/mach-gemini/timer.c:
  * Copyright (C) 2001-2006 Storlink, Corp.
  * Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
  */
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/clockchips.h>
 #include <linux/clocksource.h>
 #include <linux/sched_clock.h>
 #include <linux/clk.h>
 #include <linux/slab.h>
 #include <linux/bitops.h>
 #include <linux/delay.h>

 /*
  * Register definitions common for all the timer variants.
  */
 #define TIMER1_COUNT		(0x00)
 #define TIMER1_LOAD		(0x04)
 #define TIMER1_MATCH1		(0x08)
 #define TIMER1_MATCH2		(0x0c)
 #define TIMER2_COUNT		(0x10)
 #define TIMER2_LOAD		(0x14)
 #define TIMER2_MATCH1		(0x18)
 #define TIMER2_MATCH2		(0x1c)
 #define TIMER3_COUNT		(0x20)
 #define TIMER3_LOAD		(0x24)
 #define TIMER3_MATCH1		(0x28)
 #define TIMER3_MATCH2		(0x2c)
 #define TIMER_CR		(0x30)

 /*
  * Control register (TMC30) bit fields for fttmr010/gemini/moxart timers.
  */
 #define TIMER_1_CR_ENABLE	BIT(0)
 #define TIMER_1_CR_CLOCK	BIT(1)
 #define TIMER_1_CR_INT		BIT(2)
 #define TIMER_2_CR_ENABLE	BIT(3)
 #define TIMER_2_CR_CLOCK	BIT(4)
 #define TIMER_2_CR_INT		BIT(5)
 #define TIMER_3_CR_ENABLE	BIT(6)
 #define TIMER_3_CR_CLOCK	BIT(7)
 #define TIMER_3_CR_INT		BIT(8)
 #define TIMER_1_CR_UPDOWN	BIT(9)
 #define TIMER_2_CR_UPDOWN	BIT(10)
 #define TIMER_3_CR_UPDOWN	BIT(11)

 /*
  * Control register (TMC30) bit fields for aspeed ast2400/ast2500 timers.
  * The aspeed timers move bits around in the control register and lacks
  * bits for setting the timer to count upwards.
  */
 #define TIMER_1_CR_ASPEED_ENABLE	BIT(0)
 #define TIMER_1_CR_ASPEED_CLOCK		BIT(1)
 #define TIMER_1_CR_ASPEED_INT		BIT(2)
 #define TIMER_2_CR_ASPEED_ENABLE	BIT(4)
 #define TIMER_2_CR_ASPEED_CLOCK		BIT(5)
 #define TIMER_2_CR_ASPEED_INT		BIT(6)
 #define TIMER_3_CR_ASPEED_ENABLE	BIT(8)
 #define TIMER_3_CR_ASPEED_CLOCK		BIT(9)
 #define TIMER_3_CR_ASPEED_INT		BIT(10)

 /*
  * Interrupt status/mask register definitions for fttmr010/gemini/moxart
  * timers.
  * The registers don't exist and they are not needed on aspeed timers
  * because:
  *   - aspeed timer overflow interrupt is controlled by bits in Control
  *     Register (TMC30).
  *   - aspeed timers always generate interrupt when either one of the
  *     Match registers equals to Status register.
  */
 #define TIMER_INTR_STATE	(0x34)
 #define TIMER_INTR_MASK		(0x38)
 #define TIMER_1_INT_MATCH1	BIT(0)
 #define TIMER_1_INT_MATCH2	BIT(1)
 #define TIMER_1_INT_OVERFLOW	BIT(2)
 #define TIMER_2_INT_MATCH1	BIT(3)
 #define TIMER_2_INT_MATCH2	BIT(4)
 #define TIMER_2_INT_OVERFLOW	BIT(5)
 #define TIMER_3_INT_MATCH1	BIT(6)
 #define TIMER_3_INT_MATCH2	BIT(7)
 #define TIMER_3_INT_OVERFLOW	BIT(8)
 #define TIMER_INT_ALL_MASK	0x1ff

 struct fttmr010 {
 	void __iomem *base;
 	unsigned int tick_rate;
 	bool is_aspeed;
 	u32 t1_enable_val;
 	struct clock_event_device clkevt;
 #ifdef CONFIG_ARM
 	struct delay_timer delay_timer;
 #endif
 };

 /*
  * A local singleton used by sched_clock and delay timer reads, which are
  * fast and stateless
  */
 static struct fttmr010 *local_fttmr;

 static inline struct fttmr010 *to_fttmr010(struct clock_event_device *evt)
 {
 	return container_of(evt, struct fttmr010, clkevt);
 }

 static unsigned long fttmr010_read_current_timer_up(void)
 {
 	return readl(local_fttmr->base + TIMER2_COUNT);
 }

 static unsigned long fttmr010_read_current_timer_down(void)
 {
 	return ~readl(local_fttmr->base + TIMER2_COUNT);
 }

 static u64 notrace fttmr010_read_sched_clock_up(void)
 {
 	return fttmr010_read_current_timer_up();
 }

 static u64 notrace fttmr010_read_sched_clock_down(void)
 {
 	return fttmr010_read_current_timer_down();
 }

 static int fttmr010_timer_set_next_event(unsigned long cycles,
 				       struct clock_event_device *evt)
 {
 	struct fttmr010 *fttmr010 = to_fttmr010(evt);
 	u32 cr;

 	/* Stop */
 	cr = readl(fttmr010->base + TIMER_CR);
 	cr &= ~fttmr010->t1_enable_val;
 	writel(cr, fttmr010->base + TIMER_CR);

 	if (fttmr010->is_aspeed) {
 		/*
 		 * ASPEED Timer Controller will load TIMER1_LOAD register
 		 * into TIMER1_COUNT register when the timer is re-enabled.
 		 */
 		writel(cycles, fttmr010->base + TIMER1_LOAD);
 	} else {
 		/* Setup the match register forward in time */
 		cr = readl(fttmr010->base + TIMER1_COUNT);
 		writel(cr + cycles, fttmr010->base + TIMER1_MATCH1);
 	}

 	/* Start */
 	cr = readl(fttmr010->base + TIMER_CR);
 	cr |= fttmr010->t1_enable_val;
 	writel(cr, fttmr010->base + TIMER_CR);

 	return 0;
 }

 static int fttmr010_timer_shutdown(struct clock_event_device *evt)
 {
 	struct fttmr010 *fttmr010 = to_fttmr010(evt);
 	u32 cr;

 	/* Stop */
 	cr = readl(fttmr010->base + TIMER_CR);
 	cr &= ~fttmr010->t1_enable_val;
 	writel(cr, fttmr010->base + TIMER_CR);

 	return 0;
 }

 static int fttmr010_timer_set_oneshot(struct clock_event_device *evt)
 {
 	struct fttmr010 *fttmr010 = to_fttmr010(evt);
 	u32 cr;

 	/* Stop */
 	cr = readl(fttmr010->base + TIMER_CR);
 	cr &= ~fttmr010->t1_enable_val;
 	writel(cr, fttmr010->base + TIMER_CR);

 	/* Setup counter start from 0 or ~0 */
 	writel(0, fttmr010->base + TIMER1_COUNT);
 	if (fttmr010->is_aspeed) {
 		writel(~0, fttmr010->base + TIMER1_LOAD);
 	} else {
 		writel(0, fttmr010->base + TIMER1_LOAD);

 		/* Enable interrupt */
 		cr = readl(fttmr010->base + TIMER_INTR_MASK);
 		cr &= ~(TIMER_1_INT_OVERFLOW | TIMER_1_INT_MATCH2);
 		cr |= TIMER_1_INT_MATCH1;
 		writel(cr, fttmr010->base + TIMER_INTR_MASK);
 	}

 	return 0;
 }

 static int fttmr010_timer_set_periodic(struct clock_event_device *evt)
 {
 	struct fttmr010 *fttmr010 = to_fttmr010(evt);
 	u32 period = DIV_ROUND_CLOSEST(fttmr010->tick_rate, HZ);
 	u32 cr;

 	/* Stop */
 	cr = readl(fttmr010->base + TIMER_CR);
 	cr &= ~fttmr010->t1_enable_val;
 	writel(cr, fttmr010->base + TIMER_CR);

 	/* Setup timer to fire at 1/HZ intervals. */
 	if (fttmr010->is_aspeed) {
 		writel(period, fttmr010->base + TIMER1_LOAD);
 	} else {
 		cr = 0xffffffff - (period - 1);
 		writel(cr, fttmr010->base + TIMER1_COUNT);
 		writel(cr, fttmr010->base + TIMER1_LOAD);

 		/* Enable interrupt on overflow */
 		cr = readl(fttmr010->base + TIMER_INTR_MASK);
 		cr &= ~(TIMER_1_INT_MATCH1 | TIMER_1_INT_MATCH2);
 		cr |= TIMER_1_INT_OVERFLOW;
 		writel(cr, fttmr010->base + TIMER_INTR_MASK);
 	}

 	/* Start the timer */
 	cr = readl(fttmr010->base + TIMER_CR);
 	cr |= fttmr010->t1_enable_val;
 	writel(cr, fttmr010->base + TIMER_CR);

 	return 0;
 }

 /*
  * IRQ handler for the timer
  */
 static irqreturn_t fttmr010_timer_interrupt(int irq, void *dev_id)
 {
 	struct clock_event_device *evt = dev_id;

 	evt->event_handler(evt);
 	return IRQ_HANDLED;
 }

 static int __init fttmr010_common_init(struct device_node *np, bool is_aspeed)
 {
 	struct fttmr010 *fttmr010;
 	int irq;
 	struct clk *clk;
 	int ret;
 	u32 val;

 	/*
 	 * These implementations require a clock reference.
 	 * FIXME: we currently only support clocking using PCLK
 	 * and using EXTCLK is not supported in the driver.
 	 */
 	clk = of_clk_get_by_name(np, "PCLK");
 	if (IS_ERR(clk)) {
 		pr_err("could not get PCLK\n");
 		return PTR_ERR(clk);
 	}
 	ret = clk_prepare_enable(clk);
 	if (ret) {
 		pr_err("failed to enable PCLK\n");
 		return ret;
 	}

 	fttmr010 = kzalloc(sizeof(*fttmr010), GFP_KERNEL);
 	if (!fttmr010) {
 		ret = -ENOMEM;
 		goto out_disable_clock;
 	}
 	fttmr010->tick_rate = clk_get_rate(clk);

 	fttmr010->base = of_iomap(np, 0);
 	if (!fttmr010->base) {
 		pr_err("Can't remap registers\n");
 		ret = -ENXIO;
 		goto out_free;
 	}
 	/* IRQ for timer 1 */
 	irq = irq_of_parse_and_map(np, 0);
 	if (irq <= 0) {
 		pr_err("Can't parse IRQ\n");
 		ret = -EINVAL;
 		goto out_unmap;
 	}

 	/*
 	 * The Aspeed timers move bits around in the control register.
 	 */
 	if (is_aspeed) {
 		fttmr010->t1_enable_val = TIMER_1_CR_ASPEED_ENABLE |
 			TIMER_1_CR_ASPEED_INT;
 		fttmr010->is_aspeed = true;
 	} else {
 		fttmr010->t1_enable_val = TIMER_1_CR_ENABLE | TIMER_1_CR_INT;

 		/*
 		 * Reset the interrupt mask and status
 		 */
 		writel(TIMER_INT_ALL_MASK, fttmr010->base + TIMER_INTR_MASK);
 		writel(0, fttmr010->base + TIMER_INTR_STATE);
 	}

 	/*
 	 * Enable timer 1 count up, timer 2 count up, except on Aspeed,
 	 * where everything just counts down.
 	 */
 	if (is_aspeed)
 		val = TIMER_2_CR_ASPEED_ENABLE;
 	else {
 		val = TIMER_2_CR_ENABLE | TIMER_1_CR_UPDOWN |
 			TIMER_2_CR_UPDOWN;
 	}
 	writel(val, fttmr010->base + TIMER_CR);

 	/*
 	 * Setup free-running clocksource timer (interrupts
 	 * disabled.)
 	 */
 	local_fttmr = fttmr010;
 	writel(0, fttmr010->base + TIMER2_COUNT);
 	writel(0, fttmr010->base + TIMER2_MATCH1);
 	writel(0, fttmr010->base + TIMER2_MATCH2);

 	if (fttmr010->is_aspeed) {
 		writel(~0, fttmr010->base + TIMER2_LOAD);
 		clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
 				      "FTTMR010-TIMER2",
 				      fttmr010->tick_rate,
 				      300, 32, clocksource_mmio_readl_down);
 		sched_clock_register(fttmr010_read_sched_clock_down, 32,
 				     fttmr010->tick_rate);
 	} else {
 		writel(0, fttmr010->base + TIMER2_LOAD);
 		clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
 				      "FTTMR010-TIMER2",
 				      fttmr010->tick_rate,
 				      300, 32, clocksource_mmio_readl_up);
 		sched_clock_register(fttmr010_read_sched_clock_up, 32,
 				     fttmr010->tick_rate);
 	}

 	/*
 	 * Setup clockevent timer (interrupt-driven) on timer 1.
 	 */
 	writel(0, fttmr010->base + TIMER1_COUNT);
 	writel(0, fttmr010->base + TIMER1_LOAD);
 	writel(0, fttmr010->base + TIMER1_MATCH1);
 	writel(0, fttmr010->base + TIMER1_MATCH2);
 	ret = request_irq(irq, fttmr010_timer_interrupt, IRQF_TIMER,
 			  "FTTMR010-TIMER1", &fttmr010->clkevt);
 	if (ret) {
 		pr_err("FTTMR010-TIMER1 no IRQ\n");
 		goto out_unmap;
 	}

 	fttmr010->clkevt.name = "FTTMR010-TIMER1";
 	/* Reasonably fast and accurate clock event */
 	fttmr010->clkevt.rating = 300;
 	fttmr010->clkevt.features = CLOCK_EVT_FEAT_PERIODIC |
 		CLOCK_EVT_FEAT_ONESHOT;
 	fttmr010->clkevt.set_next_event = fttmr010_timer_set_next_event;
 	fttmr010->clkevt.set_state_shutdown = fttmr010_timer_shutdown;
 	fttmr010->clkevt.set_state_periodic = fttmr010_timer_set_periodic;
 	fttmr010->clkevt.set_state_oneshot = fttmr010_timer_set_oneshot;
 	fttmr010->clkevt.tick_resume = fttmr010_timer_shutdown;
 	fttmr010->clkevt.cpumask = cpumask_of(0);
 	fttmr010->clkevt.irq = irq;
 	clockevents_config_and_register(&fttmr010->clkevt,
 					fttmr010->tick_rate,
 					1, 0xffffffff);

 #ifdef CONFIG_ARM
 	/* Also use this timer for delays */
 	if (fttmr010->is_aspeed)
 		fttmr010->delay_timer.read_current_timer =
 			fttmr010_read_current_timer_down;
 	else
 		fttmr010->delay_timer.read_current_timer =
 			fttmr010_read_current_timer_up;
 	fttmr010->delay_timer.freq = fttmr010->tick_rate;
 	register_current_timer_delay(&fttmr010->delay_timer);
 #endif

 	return 0;

 out_unmap:
 	iounmap(fttmr010->base);
 out_free:
 	kfree(fttmr010);
 out_disable_clock:
 	clk_disable_unprepare(clk);

 	return ret;
 }

 static __init int aspeed_timer_init(struct device_node *np)
 {
 	return fttmr010_common_init(np, true);
 }

 static __init int fttmr010_timer_init(struct device_node *np)
 {
 	return fttmr010_common_init(np, false);
 }

 TIMER_OF_DECLARE(fttmr010, "faraday,fttmr010", fttmr010_timer_init);
 TIMER_OF_DECLARE(gemini, "cortina,gemini-timer", fttmr010_timer_init);
 TIMER_OF_DECLARE(moxart, "moxa,moxart-timer", fttmr010_timer_init);
 TIMER_OF_DECLARE(ast2400, "aspeed,ast2400-timer", aspeed_timer_init);
 TIMER_OF_DECLARE(ast2500, "aspeed,ast2500-timer", aspeed_timer_init);
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Faraday Technology FTTMR010 timer driver
	* Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
	*
	* Based on a rewrite of arch/arm/mach-gemini/timer.c:
	* Copyright (C) 2001-2006 Storlink, Corp.
	* Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
	*/
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/clockchips.h>
	#include <linux/clocksource.h>
	#include <linux/sched_clock.h>
	#include <linux/clk.h>
	#include <linux/slab.h>
	#include <linux/bitops.h>
	#include <linux/delay.h>

	/*
	* Register definitions common for all the timer variants.
	*/
	#define TIMER1_COUNT (0x00)
	#define TIMER1_LOAD (0x04)
	#define TIMER1_MATCH1 (0x08)
	#define TIMER1_MATCH2 (0x0c)
	#define TIMER2_COUNT (0x10)
	#define TIMER2_LOAD (0x14)
	#define TIMER2_MATCH1 (0x18)
	#define TIMER2_MATCH2 (0x1c)
	#define TIMER3_COUNT (0x20)
	#define TIMER3_LOAD (0x24)
	#define TIMER3_MATCH1 (0x28)
	#define TIMER3_MATCH2 (0x2c)
	#define TIMER_CR (0x30)

	/*
	* Control register (TMC30) bit fields for fttmr010/gemini/moxart timers.
	*/
	#define TIMER_1_CR_ENABLE BIT(0)
	#define TIMER_1_CR_CLOCK BIT(1)
	#define TIMER_1_CR_INT BIT(2)
	#define TIMER_2_CR_ENABLE BIT(3)
	#define TIMER_2_CR_CLOCK BIT(4)
	#define TIMER_2_CR_INT BIT(5)
	#define TIMER_3_CR_ENABLE BIT(6)
	#define TIMER_3_CR_CLOCK BIT(7)
	#define TIMER_3_CR_INT BIT(8)
	#define TIMER_1_CR_UPDOWN BIT(9)
	#define TIMER_2_CR_UPDOWN BIT(10)
	#define TIMER_3_CR_UPDOWN BIT(11)

	/*
	* Control register (TMC30) bit fields for aspeed ast2400/ast2500 timers.
	* The aspeed timers move bits around in the control register and lacks
	* bits for setting the timer to count upwards.
	*/
	#define TIMER_1_CR_ASPEED_ENABLE BIT(0)
	#define TIMER_1_CR_ASPEED_CLOCK BIT(1)
	#define TIMER_1_CR_ASPEED_INT BIT(2)
	#define TIMER_2_CR_ASPEED_ENABLE BIT(4)
	#define TIMER_2_CR_ASPEED_CLOCK BIT(5)
	#define TIMER_2_CR_ASPEED_INT BIT(6)
	#define TIMER_3_CR_ASPEED_ENABLE BIT(8)
	#define TIMER_3_CR_ASPEED_CLOCK BIT(9)
	#define TIMER_3_CR_ASPEED_INT BIT(10)

	/*
	* Interrupt status/mask register definitions for fttmr010/gemini/moxart
	* timers.
	* The registers don't exist and they are not needed on aspeed timers
	* because:
	* - aspeed timer overflow interrupt is controlled by bits in Control
	* Register (TMC30).
	* - aspeed timers always generate interrupt when either one of the
	* Match registers equals to Status register.
	*/
	#define TIMER_INTR_STATE (0x34)
	#define TIMER_INTR_MASK (0x38)
	#define TIMER_1_INT_MATCH1 BIT(0)
	#define TIMER_1_INT_MATCH2 BIT(1)
	#define TIMER_1_INT_OVERFLOW BIT(2)
	#define TIMER_2_INT_MATCH1 BIT(3)
	#define TIMER_2_INT_MATCH2 BIT(4)
	#define TIMER_2_INT_OVERFLOW BIT(5)
	#define TIMER_3_INT_MATCH1 BIT(6)
	#define TIMER_3_INT_MATCH2 BIT(7)
	#define TIMER_3_INT_OVERFLOW BIT(8)
	#define TIMER_INT_ALL_MASK 0x1ff

	struct fttmr010 {
	void __iomem *base;
	unsigned int tick_rate;
	bool is_aspeed;
	u32 t1_enable_val;
	struct clock_event_device clkevt;
	#ifdef CONFIG_ARM
	struct delay_timer delay_timer;
	#endif
	};

	/*
	* A local singleton used by sched_clock and delay timer reads, which are
	* fast and stateless
	*/
	static struct fttmr010 *local_fttmr;

	static inline struct fttmr010 to_fttmr010(struct clock_event_device evt)
	{
	return container_of(evt, struct fttmr010, clkevt);
	}

	static unsigned long fttmr010_read_current_timer_up(void)
	{
	return readl(local_fttmr->base + TIMER2_COUNT);
	}

	static unsigned long fttmr010_read_current_timer_down(void)
	{
	return ~readl(local_fttmr->base + TIMER2_COUNT);
	}

	static u64 notrace fttmr010_read_sched_clock_up(void)
	{
	return fttmr010_read_current_timer_up();
	}

	static u64 notrace fttmr010_read_sched_clock_down(void)
	{
	return fttmr010_read_current_timer_down();
	}

	static int fttmr010_timer_set_next_event(unsigned long cycles,
	struct clock_event_device *evt)
	{
	struct fttmr010 *fttmr010 = to_fttmr010(evt);
	u32 cr;

	/* Stop */
	cr = readl(fttmr010->base + TIMER_CR);
	cr &= ~fttmr010->t1_enable_val;
	writel(cr, fttmr010->base + TIMER_CR);

	if (fttmr010->is_aspeed) {
	/*
	* ASPEED Timer Controller will load TIMER1_LOAD register
	* into TIMER1_COUNT register when the timer is re-enabled.
	*/
	writel(cycles, fttmr010->base + TIMER1_LOAD);
	} else {
	/* Setup the match register forward in time */
	cr = readl(fttmr010->base + TIMER1_COUNT);
	writel(cr + cycles, fttmr010->base + TIMER1_MATCH1);
	}

	/* Start */
	cr = readl(fttmr010->base + TIMER_CR);
	cr \|= fttmr010->t1_enable_val;
	writel(cr, fttmr010->base + TIMER_CR);

	return 0;
	}

	static int fttmr010_timer_shutdown(struct clock_event_device *evt)
	{
	struct fttmr010 *fttmr010 = to_fttmr010(evt);
	u32 cr;

	/* Stop */
	cr = readl(fttmr010->base + TIMER_CR);
	cr &= ~fttmr010->t1_enable_val;
	writel(cr, fttmr010->base + TIMER_CR);

	return 0;
	}

	static int fttmr010_timer_set_oneshot(struct clock_event_device *evt)
	{
	struct fttmr010 *fttmr010 = to_fttmr010(evt);
	u32 cr;

	/* Stop */
	cr = readl(fttmr010->base + TIMER_CR);
	cr &= ~fttmr010->t1_enable_val;
	writel(cr, fttmr010->base + TIMER_CR);

	/* Setup counter start from 0 or ~0 */
	writel(0, fttmr010->base + TIMER1_COUNT);
	if (fttmr010->is_aspeed) {
	writel(~0, fttmr010->base + TIMER1_LOAD);
	} else {
	writel(0, fttmr010->base + TIMER1_LOAD);

	/* Enable interrupt */
	cr = readl(fttmr010->base + TIMER_INTR_MASK);
	cr &= ~(TIMER_1_INT_OVERFLOW \| TIMER_1_INT_MATCH2);
	cr \|= TIMER_1_INT_MATCH1;
	writel(cr, fttmr010->base + TIMER_INTR_MASK);
	}

	return 0;
	}

	static int fttmr010_timer_set_periodic(struct clock_event_device *evt)
	{
	struct fttmr010 *fttmr010 = to_fttmr010(evt);
	u32 period = DIV_ROUND_CLOSEST(fttmr010->tick_rate, HZ);
	u32 cr;

	/* Stop */
	cr = readl(fttmr010->base + TIMER_CR);
	cr &= ~fttmr010->t1_enable_val;
	writel(cr, fttmr010->base + TIMER_CR);

	/* Setup timer to fire at 1/HZ intervals. */
	if (fttmr010->is_aspeed) {
	writel(period, fttmr010->base + TIMER1_LOAD);
	} else {
	cr = 0xffffffff - (period - 1);
	writel(cr, fttmr010->base + TIMER1_COUNT);
	writel(cr, fttmr010->base + TIMER1_LOAD);

	/* Enable interrupt on overflow */
	cr = readl(fttmr010->base + TIMER_INTR_MASK);
	cr &= ~(TIMER_1_INT_MATCH1 \| TIMER_1_INT_MATCH2);
	cr \|= TIMER_1_INT_OVERFLOW;
	writel(cr, fttmr010->base + TIMER_INTR_MASK);
	}

	/* Start the timer */
	cr = readl(fttmr010->base + TIMER_CR);
	cr \|= fttmr010->t1_enable_val;
	writel(cr, fttmr010->base + TIMER_CR);

	return 0;
	}

	/*
	* IRQ handler for the timer
	*/
	static irqreturn_t fttmr010_timer_interrupt(int irq, void *dev_id)
	{
	struct clock_event_device *evt = dev_id;

	evt->event_handler(evt);
	return IRQ_HANDLED;
	}

	static int __init fttmr010_common_init(struct device_node *np, bool is_aspeed)
	{
	struct fttmr010 *fttmr010;
	int irq;
	struct clk *clk;
	int ret;
	u32 val;

	/*
	* These implementations require a clock reference.
	* FIXME: we currently only support clocking using PCLK
	* and using EXTCLK is not supported in the driver.
	*/
	clk = of_clk_get_by_name(np, "PCLK");
	if (IS_ERR(clk)) {
	pr_err("could not get PCLK\n");
	return PTR_ERR(clk);
	}
	ret = clk_prepare_enable(clk);
	if (ret) {
	pr_err("failed to enable PCLK\n");
	return ret;
	}

	fttmr010 = kzalloc(sizeof(*fttmr010), GFP_KERNEL);
	if (!fttmr010) {
	ret = -ENOMEM;
	goto out_disable_clock;
	}
	fttmr010->tick_rate = clk_get_rate(clk);

	fttmr010->base = of_iomap(np, 0);
	if (!fttmr010->base) {
	pr_err("Can't remap registers\n");
	ret = -ENXIO;
	goto out_free;
	}
	/* IRQ for timer 1 */
	irq = irq_of_parse_and_map(np, 0);
	if (irq <= 0) {
	pr_err("Can't parse IRQ\n");
	ret = -EINVAL;
	goto out_unmap;
	}

	/*
	* The Aspeed timers move bits around in the control register.
	*/
	if (is_aspeed) {
	fttmr010->t1_enable_val = TIMER_1_CR_ASPEED_ENABLE \|
	TIMER_1_CR_ASPEED_INT;
	fttmr010->is_aspeed = true;
	} else {
	fttmr010->t1_enable_val = TIMER_1_CR_ENABLE \| TIMER_1_CR_INT;

	/*
	* Reset the interrupt mask and status
	*/
	writel(TIMER_INT_ALL_MASK, fttmr010->base + TIMER_INTR_MASK);
	writel(0, fttmr010->base + TIMER_INTR_STATE);
	}

	/*
	* Enable timer 1 count up, timer 2 count up, except on Aspeed,
	* where everything just counts down.
	*/
	if (is_aspeed)
	val = TIMER_2_CR_ASPEED_ENABLE;
	else {
	val = TIMER_2_CR_ENABLE \| TIMER_1_CR_UPDOWN \|
	TIMER_2_CR_UPDOWN;
	}
	writel(val, fttmr010->base + TIMER_CR);

	/*
	* Setup free-running clocksource timer (interrupts
	* disabled.)
	*/
	local_fttmr = fttmr010;
	writel(0, fttmr010->base + TIMER2_COUNT);
	writel(0, fttmr010->base + TIMER2_MATCH1);
	writel(0, fttmr010->base + TIMER2_MATCH2);

	if (fttmr010->is_aspeed) {
	writel(~0, fttmr010->base + TIMER2_LOAD);
	clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
	"FTTMR010-TIMER2",
	fttmr010->tick_rate,
	300, 32, clocksource_mmio_readl_down);
	sched_clock_register(fttmr010_read_sched_clock_down, 32,
	fttmr010->tick_rate);
	} else {
	writel(0, fttmr010->base + TIMER2_LOAD);
	clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
	"FTTMR010-TIMER2",
	fttmr010->tick_rate,
	300, 32, clocksource_mmio_readl_up);
	sched_clock_register(fttmr010_read_sched_clock_up, 32,
	fttmr010->tick_rate);
	}

	/*
	* Setup clockevent timer (interrupt-driven) on timer 1.
	*/
	writel(0, fttmr010->base + TIMER1_COUNT);
	writel(0, fttmr010->base + TIMER1_LOAD);
	writel(0, fttmr010->base + TIMER1_MATCH1);
	writel(0, fttmr010->base + TIMER1_MATCH2);
	ret = request_irq(irq, fttmr010_timer_interrupt, IRQF_TIMER,
	"FTTMR010-TIMER1", &fttmr010->clkevt);
	if (ret) {
	pr_err("FTTMR010-TIMER1 no IRQ\n");
	goto out_unmap;
	}

	fttmr010->clkevt.name = "FTTMR010-TIMER1";
	/* Reasonably fast and accurate clock event */
	fttmr010->clkevt.rating = 300;
	fttmr010->clkevt.features = CLOCK_EVT_FEAT_PERIODIC \|
	CLOCK_EVT_FEAT_ONESHOT;
	fttmr010->clkevt.set_next_event = fttmr010_timer_set_next_event;
	fttmr010->clkevt.set_state_shutdown = fttmr010_timer_shutdown;
	fttmr010->clkevt.set_state_periodic = fttmr010_timer_set_periodic;
	fttmr010->clkevt.set_state_oneshot = fttmr010_timer_set_oneshot;
	fttmr010->clkevt.tick_resume = fttmr010_timer_shutdown;
	fttmr010->clkevt.cpumask = cpumask_of(0);
	fttmr010->clkevt.irq = irq;
	clockevents_config_and_register(&fttmr010->clkevt,
	fttmr010->tick_rate,
	1, 0xffffffff);

	#ifdef CONFIG_ARM
	/* Also use this timer for delays */
	if (fttmr010->is_aspeed)
	fttmr010->delay_timer.read_current_timer =
	fttmr010_read_current_timer_down;
	else
	fttmr010->delay_timer.read_current_timer =
	fttmr010_read_current_timer_up;
	fttmr010->delay_timer.freq = fttmr010->tick_rate;
	register_current_timer_delay(&fttmr010->delay_timer);
	#endif

	return 0;

	out_unmap:
	iounmap(fttmr010->base);
	out_free:
	kfree(fttmr010);
	out_disable_clock:
	clk_disable_unprepare(clk);

	return ret;
	}

	static __init int aspeed_timer_init(struct device_node *np)
	{
	return fttmr010_common_init(np, true);
	}

	static __init int fttmr010_timer_init(struct device_node *np)
	{
	return fttmr010_common_init(np, false);
	}

	TIMER_OF_DECLARE(fttmr010, "faraday,fttmr010", fttmr010_timer_init);
	TIMER_OF_DECLARE(gemini, "cortina,gemini-timer", fttmr010_timer_init);
	TIMER_OF_DECLARE(moxart, "moxa,moxart-timer", fttmr010_timer_init);
	TIMER_OF_DECLARE(ast2400, "aspeed,ast2400-timer", aspeed_timer_init);
	TIMER_OF_DECLARE(ast2500, "aspeed,ast2500-timer", aspeed_timer_init);