drivers/clocksource/timer-mediatek.c - linux/kernel/git/torvalds/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Mediatek SoCs General-Purpose Timer handling.
  *
  * Copyright (C) 2014 Matthias Brugger
  *
  * Matthias Brugger <matthias.bgg@gmail.com>
  */

 #define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt

 #include <linux/clockchips.h>
 #include <linux/clocksource.h>
 #include <linux/interrupt.h>
 #include <linux/irqreturn.h>
 #include <linux/sched_clock.h>
 #include <linux/slab.h>
 #include "timer-of.h"

 #define TIMER_CLK_EVT           (1)
 #define TIMER_CLK_SRC           (2)

 #define TIMER_SYNC_TICKS        (3)

 /* cpux mcusys wrapper */
 #define CPUX_CON_REG		0x0
 #define CPUX_IDX_REG		0x4

 /* cpux */
 #define CPUX_IDX_GLOBAL_CTRL	0x0
  #define CPUX_ENABLE		BIT(0)
  #define CPUX_CLK_DIV_MASK	GENMASK(10, 8)
  #define CPUX_CLK_DIV1		BIT(8)
  #define CPUX_CLK_DIV2		BIT(9)
  #define CPUX_CLK_DIV4		BIT(10)
 #define CPUX_IDX_GLOBAL_IRQ	0x30

 /* gpt */
 #define GPT_IRQ_EN_REG          0x00
 #define GPT_IRQ_ENABLE(val)     BIT((val) - 1)
 #define GPT_IRQ_ACK_REG	        0x08
 #define GPT_IRQ_ACK(val)        BIT((val) - 1)

 #define GPT_CTRL_REG(val)       (0x10 * (val))
 #define GPT_CTRL_OP(val)        (((val) & 0x3) << 4)
 #define GPT_CTRL_OP_ONESHOT     (0)
 #define GPT_CTRL_OP_REPEAT      (1)
 #define GPT_CTRL_OP_FREERUN     (3)
 #define GPT_CTRL_CLEAR          (2)
 #define GPT_CTRL_ENABLE         (1)
 #define GPT_CTRL_DISABLE        (0)

 #define GPT_CLK_REG(val)        (0x04 + (0x10 * (val)))
 #define GPT_CLK_SRC(val)        (((val) & 0x1) << 4)
 #define GPT_CLK_SRC_SYS13M      (0)
 #define GPT_CLK_SRC_RTC32K      (1)
 #define GPT_CLK_DIV1            (0x0)
 #define GPT_CLK_DIV2            (0x1)

 #define GPT_CNT_REG(val)        (0x08 + (0x10 * (val)))
 #define GPT_CMP_REG(val)        (0x0C + (0x10 * (val)))

 /* system timer */
 #define SYST_BASE               (0x40)

 #define SYST_CON                (SYST_BASE + 0x0)
 #define SYST_VAL                (SYST_BASE + 0x4)

 #define SYST_CON_REG(to)        (timer_of_base(to) + SYST_CON)
 #define SYST_VAL_REG(to)        (timer_of_base(to) + SYST_VAL)

 /*
  * SYST_CON_EN: Clock enable. Shall be set to
  *   - Start timer countdown.
  *   - Allow timeout ticks being updated.
  *   - Allow changing interrupt status,like clear irq pending.
  *
  * SYST_CON_IRQ_EN: Set to enable interrupt.
  *
  * SYST_CON_IRQ_CLR: Set to clear interrupt.
  */
 #define SYST_CON_EN              BIT(0)
 #define SYST_CON_IRQ_EN          BIT(1)
 #define SYST_CON_IRQ_CLR         BIT(4)

 static void __iomem *gpt_sched_reg __read_mostly;

 static u32 mtk_cpux_readl(u32 reg_idx, struct timer_of *to)
 {
 	writel(reg_idx, timer_of_base(to) + CPUX_IDX_REG);
 	return readl(timer_of_base(to) + CPUX_CON_REG);
 }

 static void mtk_cpux_writel(u32 val, u32 reg_idx, struct timer_of *to)
 {
 	writel(reg_idx, timer_of_base(to) + CPUX_IDX_REG);
 	writel(val, timer_of_base(to) + CPUX_CON_REG);
 }

 static void mtk_cpux_set_irq(struct timer_of *to, bool enable)
 {
 	const unsigned long *irq_mask = cpumask_bits(cpu_possible_mask);
 	u32 val;

 	val = mtk_cpux_readl(CPUX_IDX_GLOBAL_IRQ, to);

 	if (enable)
 		val |= *irq_mask;
 	else
 		val &= ~(*irq_mask);

 	mtk_cpux_writel(val, CPUX_IDX_GLOBAL_IRQ, to);
 }

 static int mtk_cpux_clkevt_shutdown(struct clock_event_device *clkevt)
 {
 	/* Clear any irq */
 	mtk_cpux_set_irq(to_timer_of(clkevt), false);

 	/*
 	 * Disabling CPUXGPT timer will crash the platform, especially
 	 * if Trusted Firmware is using it (usually, for sleep states),
 	 * so we only mask the IRQ and call it a day.
 	 */
 	return 0;
 }

 static int mtk_cpux_clkevt_resume(struct clock_event_device *clkevt)
 {
 	mtk_cpux_set_irq(to_timer_of(clkevt), true);
 	return 0;
 }

 static void mtk_syst_ack_irq(struct timer_of *to)
 {
 	/* Clear and disable interrupt */
 	writel(SYST_CON_EN, SYST_CON_REG(to));
 	writel(SYST_CON_IRQ_CLR | SYST_CON_EN, SYST_CON_REG(to));
 }

 static irqreturn_t mtk_syst_handler(int irq, void *dev_id)
 {
 	struct clock_event_device *clkevt = dev_id;
 	struct timer_of *to = to_timer_of(clkevt);

 	mtk_syst_ack_irq(to);
 	clkevt->event_handler(clkevt);

 	return IRQ_HANDLED;
 }

 static int mtk_syst_clkevt_next_event(unsigned long ticks,
 				      struct clock_event_device *clkevt)
 {
 	struct timer_of *to = to_timer_of(clkevt);

 	/* Enable clock to allow timeout tick update later */
 	writel(SYST_CON_EN, SYST_CON_REG(to));

 	/*
 	 * Write new timeout ticks. Timer shall start countdown
 	 * after timeout ticks are updated.
 	 */
 	writel(ticks, SYST_VAL_REG(to));

 	/* Enable interrupt */
 	writel(SYST_CON_EN | SYST_CON_IRQ_EN, SYST_CON_REG(to));

 	return 0;
 }

 static int mtk_syst_clkevt_shutdown(struct clock_event_device *clkevt)
 {
 	/* Clear any irq */
 	mtk_syst_ack_irq(to_timer_of(clkevt));

 	/* Disable timer */
 	writel(0, SYST_CON_REG(to_timer_of(clkevt)));

 	return 0;
 }

 static int mtk_syst_clkevt_resume(struct clock_event_device *clkevt)
 {
 	return mtk_syst_clkevt_shutdown(clkevt);
 }

 static int mtk_syst_clkevt_oneshot(struct clock_event_device *clkevt)
 {
 	return 0;
 }

 static u64 notrace mtk_gpt_read_sched_clock(void)
 {
 	return readl_relaxed(gpt_sched_reg);
 }

 static void mtk_gpt_clkevt_time_stop(struct timer_of *to, u8 timer)
 {
 	u32 val;

 	val = readl(timer_of_base(to) + GPT_CTRL_REG(timer));
 	writel(val & ~GPT_CTRL_ENABLE, timer_of_base(to) +
 	       GPT_CTRL_REG(timer));
 }

 static void mtk_gpt_clkevt_time_setup(struct timer_of *to,
 				      unsigned long delay, u8 timer)
 {
 	writel(delay, timer_of_base(to) + GPT_CMP_REG(timer));
 }

 static void mtk_gpt_clkevt_time_start(struct timer_of *to,
 				      bool periodic, u8 timer)
 {
 	u32 val;

 	/* Acknowledge interrupt */
 	writel(GPT_IRQ_ACK(timer), timer_of_base(to) + GPT_IRQ_ACK_REG);

 	val = readl(timer_of_base(to) + GPT_CTRL_REG(timer));

 	/* Clear 2 bit timer operation mode field */
 	val &= ~GPT_CTRL_OP(0x3);

 	if (periodic)
 		val |= GPT_CTRL_OP(GPT_CTRL_OP_REPEAT);
 	else
 		val |= GPT_CTRL_OP(GPT_CTRL_OP_ONESHOT);

 	writel(val | GPT_CTRL_ENABLE | GPT_CTRL_CLEAR,
 	       timer_of_base(to) + GPT_CTRL_REG(timer));
 }

 static int mtk_gpt_clkevt_shutdown(struct clock_event_device *clk)
 {
 	mtk_gpt_clkevt_time_stop(to_timer_of(clk), TIMER_CLK_EVT);

 	return 0;
 }

 static int mtk_gpt_clkevt_set_periodic(struct clock_event_device *clk)
 {
 	struct timer_of *to = to_timer_of(clk);

 	mtk_gpt_clkevt_time_stop(to, TIMER_CLK_EVT);
 	mtk_gpt_clkevt_time_setup(to, to->of_clk.period, TIMER_CLK_EVT);
 	mtk_gpt_clkevt_time_start(to, true, TIMER_CLK_EVT);

 	return 0;
 }

 static int mtk_gpt_clkevt_next_event(unsigned long event,
 				     struct clock_event_device *clk)
 {
 	struct timer_of *to = to_timer_of(clk);

 	mtk_gpt_clkevt_time_stop(to, TIMER_CLK_EVT);
 	mtk_gpt_clkevt_time_setup(to, event, TIMER_CLK_EVT);
 	mtk_gpt_clkevt_time_start(to, false, TIMER_CLK_EVT);

 	return 0;
 }

 static irqreturn_t mtk_gpt_interrupt(int irq, void *dev_id)
 {
 	struct clock_event_device *clkevt = (struct clock_event_device *)dev_id;
 	struct timer_of *to = to_timer_of(clkevt);

 	/* Acknowledge timer0 irq */
 	writel(GPT_IRQ_ACK(TIMER_CLK_EVT), timer_of_base(to) + GPT_IRQ_ACK_REG);
 	clkevt->event_handler(clkevt);

 	return IRQ_HANDLED;
 }

 static void
 __init mtk_gpt_setup(struct timer_of *to, u8 timer, u8 option)
 {
 	writel(GPT_CTRL_CLEAR | GPT_CTRL_DISABLE,
 	       timer_of_base(to) + GPT_CTRL_REG(timer));

 	writel(GPT_CLK_SRC(GPT_CLK_SRC_SYS13M) | GPT_CLK_DIV1,
 	       timer_of_base(to) + GPT_CLK_REG(timer));

 	writel(0x0, timer_of_base(to) + GPT_CMP_REG(timer));

 	writel(GPT_CTRL_OP(option) | GPT_CTRL_ENABLE,
 	       timer_of_base(to) + GPT_CTRL_REG(timer));
 }

 static void mtk_gpt_enable_irq(struct timer_of *to, u8 timer)
 {
 	u32 val;

 	/* Disable all interrupts */
 	writel(0x0, timer_of_base(to) + GPT_IRQ_EN_REG);

 	/* Acknowledge all spurious pending interrupts */
 	writel(0x3f, timer_of_base(to) + GPT_IRQ_ACK_REG);

 	val = readl(timer_of_base(to) + GPT_IRQ_EN_REG);
 	writel(val | GPT_IRQ_ENABLE(timer),
 	       timer_of_base(to) + GPT_IRQ_EN_REG);
 }

 static void mtk_gpt_resume(struct clock_event_device *clk)
 {
 	struct timer_of *to = to_timer_of(clk);

 	mtk_gpt_enable_irq(to, TIMER_CLK_EVT);
 }

 static void mtk_gpt_suspend(struct clock_event_device *clk)
 {
 	struct timer_of *to = to_timer_of(clk);

 	/* Disable all interrupts */
 	writel(0x0, timer_of_base(to) + GPT_IRQ_EN_REG);

 	/*
 	 * This is called with interrupts disabled,
 	 * so we need to ack any interrupt that is pending
 	 * or for example ATF will prevent a suspend from completing.
 	 */
 	writel(0x3f, timer_of_base(to) + GPT_IRQ_ACK_REG);
 }

 static struct timer_of to = {
 	.flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK,

 	.clkevt = {
 		.name = "mtk-clkevt",
 		.rating = 300,
 		.cpumask = cpu_possible_mask,
 	},

 	.of_irq = {
 		.flags = IRQF_TIMER | IRQF_IRQPOLL,
 	},
 };

 static int __init mtk_cpux_init(struct device_node *node)
 {
 	static struct timer_of to_cpux;
 	u32 freq, val;
 	int ret;

 	/*
 	 * There are per-cpu interrupts for the CPUX General Purpose Timer
 	 * but since this timer feeds the AArch64 System Timer we can rely
 	 * on the CPU timer PPIs as well, so we don't declare TIMER_OF_IRQ.
 	 */
 	to_cpux.flags = TIMER_OF_BASE | TIMER_OF_CLOCK;
 	to_cpux.clkevt.name = "mtk-cpuxgpt";
 	to_cpux.clkevt.rating = 10;
 	to_cpux.clkevt.cpumask = cpu_possible_mask;
 	to_cpux.clkevt.set_state_shutdown = mtk_cpux_clkevt_shutdown;
 	to_cpux.clkevt.tick_resume = mtk_cpux_clkevt_resume;

 	/* If this fails, bad things are about to happen... */
 	ret = timer_of_init(node, &to_cpux);
 	if (ret) {
 		WARN(1, "Cannot start CPUX timers.\n");
 		return ret;
 	}

 	/*
 	 * Check if we're given a clock with the right frequency for this
 	 * timer, otherwise warn but keep going with the setup anyway, as
 	 * that makes it possible to still boot the kernel, even though
 	 * it may not work correctly (random lockups, etc).
 	 * The reason behind this is that having an early UART may not be
 	 * possible for everyone and this gives a chance to retrieve kmsg
 	 * for eventual debugging even on consumer devices.
 	 */
 	freq = timer_of_rate(&to_cpux);
 	if (freq > 13000000)
 		WARN(1, "Requested unsupported timer frequency %u\n", freq);

 	/* Clock input is 26MHz, set DIV2 to achieve 13MHz clock */
 	val = mtk_cpux_readl(CPUX_IDX_GLOBAL_CTRL, &to_cpux);
 	val &= ~CPUX_CLK_DIV_MASK;
 	val |= CPUX_CLK_DIV2;
 	mtk_cpux_writel(val, CPUX_IDX_GLOBAL_CTRL, &to_cpux);

 	/* Enable all CPUXGPT timers */
 	val = mtk_cpux_readl(CPUX_IDX_GLOBAL_CTRL, &to_cpux);
 	mtk_cpux_writel(val | CPUX_ENABLE, CPUX_IDX_GLOBAL_CTRL, &to_cpux);

 	clockevents_config_and_register(&to_cpux.clkevt, timer_of_rate(&to_cpux),
 					TIMER_SYNC_TICKS, 0xffffffff);

 	return 0;
 }

 static int __init mtk_syst_init(struct device_node *node)
 {
 	int ret;

 	to.clkevt.features = CLOCK_EVT_FEAT_DYNIRQ | CLOCK_EVT_FEAT_ONESHOT;
 	to.clkevt.set_state_shutdown = mtk_syst_clkevt_shutdown;
 	to.clkevt.set_state_oneshot = mtk_syst_clkevt_oneshot;
 	to.clkevt.tick_resume = mtk_syst_clkevt_resume;
 	to.clkevt.set_next_event = mtk_syst_clkevt_next_event;
 	to.of_irq.handler = mtk_syst_handler;

 	ret = timer_of_init(node, &to);
 	if (ret)
 		return ret;

 	clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
 					TIMER_SYNC_TICKS, 0xffffffff);

 	return 0;
 }

 static int __init mtk_gpt_init(struct device_node *node)
 {
 	int ret;

 	to.clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
 	to.clkevt.set_state_shutdown = mtk_gpt_clkevt_shutdown;
 	to.clkevt.set_state_periodic = mtk_gpt_clkevt_set_periodic;
 	to.clkevt.set_state_oneshot = mtk_gpt_clkevt_shutdown;
 	to.clkevt.tick_resume = mtk_gpt_clkevt_shutdown;
 	to.clkevt.set_next_event = mtk_gpt_clkevt_next_event;
 	to.clkevt.suspend = mtk_gpt_suspend;
 	to.clkevt.resume = mtk_gpt_resume;
 	to.of_irq.handler = mtk_gpt_interrupt;

 	ret = timer_of_init(node, &to);
 	if (ret)
 		return ret;

 	/* Configure clock source */
 	mtk_gpt_setup(&to, TIMER_CLK_SRC, GPT_CTRL_OP_FREERUN);
 	clocksource_mmio_init(timer_of_base(&to) + GPT_CNT_REG(TIMER_CLK_SRC),
 			      node->name, timer_of_rate(&to), 300, 32,
 			      clocksource_mmio_readl_up);
 	gpt_sched_reg = timer_of_base(&to) + GPT_CNT_REG(TIMER_CLK_SRC);
 	sched_clock_register(mtk_gpt_read_sched_clock, 32, timer_of_rate(&to));

 	/* Configure clock event */
 	mtk_gpt_setup(&to, TIMER_CLK_EVT, GPT_CTRL_OP_REPEAT);
 	clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
 					TIMER_SYNC_TICKS, 0xffffffff);

 	mtk_gpt_enable_irq(&to, TIMER_CLK_EVT);

 	return 0;
 }
 TIMER_OF_DECLARE(mtk_mt6577, "mediatek,mt6577-timer", mtk_gpt_init);
 TIMER_OF_DECLARE(mtk_mt6765, "mediatek,mt6765-timer", mtk_syst_init);
 TIMER_OF_DECLARE(mtk_mt6795, "mediatek,mt6795-systimer", mtk_cpux_init);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Mediatek SoCs General-Purpose Timer handling.
	*
	* Copyright (C) 2014 Matthias Brugger
	*
	* Matthias Brugger <matthias.bgg@gmail.com>
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/clockchips.h>
	#include <linux/clocksource.h>
	#include <linux/interrupt.h>
	#include <linux/irqreturn.h>
	#include <linux/sched_clock.h>
	#include <linux/slab.h>
	#include "timer-of.h"

	#define TIMER_CLK_EVT (1)
	#define TIMER_CLK_SRC (2)

	#define TIMER_SYNC_TICKS (3)

	/* cpux mcusys wrapper */
	#define CPUX_CON_REG 0x0
	#define CPUX_IDX_REG 0x4

	/* cpux */
	#define CPUX_IDX_GLOBAL_CTRL 0x0
	#define CPUX_ENABLE BIT(0)
	#define CPUX_CLK_DIV_MASK GENMASK(10, 8)
	#define CPUX_CLK_DIV1 BIT(8)
	#define CPUX_CLK_DIV2 BIT(9)
	#define CPUX_CLK_DIV4 BIT(10)
	#define CPUX_IDX_GLOBAL_IRQ 0x30

	/* gpt */
	#define GPT_IRQ_EN_REG 0x00
	#define GPT_IRQ_ENABLE(val) BIT((val) - 1)
	#define GPT_IRQ_ACK_REG 0x08
	#define GPT_IRQ_ACK(val) BIT((val) - 1)

	#define GPT_CTRL_REG(val) (0x10 * (val))
	#define GPT_CTRL_OP(val) (((val) & 0x3) << 4)
	#define GPT_CTRL_OP_ONESHOT (0)
	#define GPT_CTRL_OP_REPEAT (1)
	#define GPT_CTRL_OP_FREERUN (3)
	#define GPT_CTRL_CLEAR (2)
	#define GPT_CTRL_ENABLE (1)
	#define GPT_CTRL_DISABLE (0)

	#define GPT_CLK_REG(val) (0x04 + (0x10 * (val)))
	#define GPT_CLK_SRC(val) (((val) & 0x1) << 4)
	#define GPT_CLK_SRC_SYS13M (0)
	#define GPT_CLK_SRC_RTC32K (1)
	#define GPT_CLK_DIV1 (0x0)
	#define GPT_CLK_DIV2 (0x1)

	#define GPT_CNT_REG(val) (0x08 + (0x10 * (val)))
	#define GPT_CMP_REG(val) (0x0C + (0x10 * (val)))

	/* system timer */
	#define SYST_BASE (0x40)

	#define SYST_CON (SYST_BASE + 0x0)
	#define SYST_VAL (SYST_BASE + 0x4)

	#define SYST_CON_REG(to) (timer_of_base(to) + SYST_CON)
	#define SYST_VAL_REG(to) (timer_of_base(to) + SYST_VAL)

	/*
	* SYST_CON_EN: Clock enable. Shall be set to
	* - Start timer countdown.
	* - Allow timeout ticks being updated.
	* - Allow changing interrupt status,like clear irq pending.
	*
	* SYST_CON_IRQ_EN: Set to enable interrupt.
	*
	* SYST_CON_IRQ_CLR: Set to clear interrupt.
	*/
	#define SYST_CON_EN BIT(0)
	#define SYST_CON_IRQ_EN BIT(1)
	#define SYST_CON_IRQ_CLR BIT(4)

	static void __iomem *gpt_sched_reg __read_mostly;

	static u32 mtk_cpux_readl(u32 reg_idx, struct timer_of *to)
	{
	writel(reg_idx, timer_of_base(to) + CPUX_IDX_REG);
	return readl(timer_of_base(to) + CPUX_CON_REG);
	}

	static void mtk_cpux_writel(u32 val, u32 reg_idx, struct timer_of *to)
	{
	writel(reg_idx, timer_of_base(to) + CPUX_IDX_REG);
	writel(val, timer_of_base(to) + CPUX_CON_REG);
	}

	static void mtk_cpux_set_irq(struct timer_of *to, bool enable)
	{
	const unsigned long *irq_mask = cpumask_bits(cpu_possible_mask);
	u32 val;

	val = mtk_cpux_readl(CPUX_IDX_GLOBAL_IRQ, to);

	if (enable)
	val \|= *irq_mask;
	else
	val &= ~(*irq_mask);

	mtk_cpux_writel(val, CPUX_IDX_GLOBAL_IRQ, to);
	}

	static int mtk_cpux_clkevt_shutdown(struct clock_event_device *clkevt)
	{
	/* Clear any irq */
	mtk_cpux_set_irq(to_timer_of(clkevt), false);

	/*
	* Disabling CPUXGPT timer will crash the platform, especially
	* if Trusted Firmware is using it (usually, for sleep states),
	* so we only mask the IRQ and call it a day.
	*/
	return 0;
	}

	static int mtk_cpux_clkevt_resume(struct clock_event_device *clkevt)
	{
	mtk_cpux_set_irq(to_timer_of(clkevt), true);
	return 0;
	}

	static void mtk_syst_ack_irq(struct timer_of *to)
	{
	/* Clear and disable interrupt */
	writel(SYST_CON_EN, SYST_CON_REG(to));
	writel(SYST_CON_IRQ_CLR \| SYST_CON_EN, SYST_CON_REG(to));
	}

	static irqreturn_t mtk_syst_handler(int irq, void *dev_id)
	{
	struct clock_event_device *clkevt = dev_id;
	struct timer_of *to = to_timer_of(clkevt);

	mtk_syst_ack_irq(to);
	clkevt->event_handler(clkevt);

	return IRQ_HANDLED;
	}

	static int mtk_syst_clkevt_next_event(unsigned long ticks,
	struct clock_event_device *clkevt)
	{
	struct timer_of *to = to_timer_of(clkevt);

	/* Enable clock to allow timeout tick update later */
	writel(SYST_CON_EN, SYST_CON_REG(to));

	/*
	* Write new timeout ticks. Timer shall start countdown
	* after timeout ticks are updated.
	*/
	writel(ticks, SYST_VAL_REG(to));

	/* Enable interrupt */
	writel(SYST_CON_EN \| SYST_CON_IRQ_EN, SYST_CON_REG(to));

	return 0;
	}

	static int mtk_syst_clkevt_shutdown(struct clock_event_device *clkevt)
	{
	/* Clear any irq */
	mtk_syst_ack_irq(to_timer_of(clkevt));

	/* Disable timer */
	writel(0, SYST_CON_REG(to_timer_of(clkevt)));

	return 0;
	}

	static int mtk_syst_clkevt_resume(struct clock_event_device *clkevt)
	{
	return mtk_syst_clkevt_shutdown(clkevt);
	}

	static int mtk_syst_clkevt_oneshot(struct clock_event_device *clkevt)
	{
	return 0;
	}

	static u64 notrace mtk_gpt_read_sched_clock(void)
	{
	return readl_relaxed(gpt_sched_reg);
	}

	static void mtk_gpt_clkevt_time_stop(struct timer_of *to, u8 timer)
	{
	u32 val;

	val = readl(timer_of_base(to) + GPT_CTRL_REG(timer));
	writel(val & ~GPT_CTRL_ENABLE, timer_of_base(to) +
	GPT_CTRL_REG(timer));
	}

	static void mtk_gpt_clkevt_time_setup(struct timer_of *to,
	unsigned long delay, u8 timer)
	{
	writel(delay, timer_of_base(to) + GPT_CMP_REG(timer));
	}

	static void mtk_gpt_clkevt_time_start(struct timer_of *to,
	bool periodic, u8 timer)
	{
	u32 val;

	/* Acknowledge interrupt */
	writel(GPT_IRQ_ACK(timer), timer_of_base(to) + GPT_IRQ_ACK_REG);

	val = readl(timer_of_base(to) + GPT_CTRL_REG(timer));

	/* Clear 2 bit timer operation mode field */
	val &= ~GPT_CTRL_OP(0x3);

	if (periodic)
	val \|= GPT_CTRL_OP(GPT_CTRL_OP_REPEAT);
	else
	val \|= GPT_CTRL_OP(GPT_CTRL_OP_ONESHOT);

	writel(val \| GPT_CTRL_ENABLE \| GPT_CTRL_CLEAR,
	timer_of_base(to) + GPT_CTRL_REG(timer));
	}

	static int mtk_gpt_clkevt_shutdown(struct clock_event_device *clk)
	{
	mtk_gpt_clkevt_time_stop(to_timer_of(clk), TIMER_CLK_EVT);

	return 0;
	}

	static int mtk_gpt_clkevt_set_periodic(struct clock_event_device *clk)
	{
	struct timer_of *to = to_timer_of(clk);

	mtk_gpt_clkevt_time_stop(to, TIMER_CLK_EVT);
	mtk_gpt_clkevt_time_setup(to, to->of_clk.period, TIMER_CLK_EVT);
	mtk_gpt_clkevt_time_start(to, true, TIMER_CLK_EVT);

	return 0;
	}

	static int mtk_gpt_clkevt_next_event(unsigned long event,
	struct clock_event_device *clk)
	{
	struct timer_of *to = to_timer_of(clk);

	mtk_gpt_clkevt_time_stop(to, TIMER_CLK_EVT);
	mtk_gpt_clkevt_time_setup(to, event, TIMER_CLK_EVT);
	mtk_gpt_clkevt_time_start(to, false, TIMER_CLK_EVT);

	return 0;
	}

	static irqreturn_t mtk_gpt_interrupt(int irq, void *dev_id)
	{
	struct clock_event_device clkevt = (struct clock_event_device )dev_id;
	struct timer_of *to = to_timer_of(clkevt);

	/* Acknowledge timer0 irq */
	writel(GPT_IRQ_ACK(TIMER_CLK_EVT), timer_of_base(to) + GPT_IRQ_ACK_REG);
	clkevt->event_handler(clkevt);

	return IRQ_HANDLED;
	}

	static void
	__init mtk_gpt_setup(struct timer_of *to, u8 timer, u8 option)
	{
	writel(GPT_CTRL_CLEAR \| GPT_CTRL_DISABLE,
	timer_of_base(to) + GPT_CTRL_REG(timer));

	writel(GPT_CLK_SRC(GPT_CLK_SRC_SYS13M) \| GPT_CLK_DIV1,
	timer_of_base(to) + GPT_CLK_REG(timer));

	writel(0x0, timer_of_base(to) + GPT_CMP_REG(timer));

	writel(GPT_CTRL_OP(option) \| GPT_CTRL_ENABLE,
	timer_of_base(to) + GPT_CTRL_REG(timer));
	}

	static void mtk_gpt_enable_irq(struct timer_of *to, u8 timer)
	{
	u32 val;

	/* Disable all interrupts */
	writel(0x0, timer_of_base(to) + GPT_IRQ_EN_REG);

	/* Acknowledge all spurious pending interrupts */
	writel(0x3f, timer_of_base(to) + GPT_IRQ_ACK_REG);

	val = readl(timer_of_base(to) + GPT_IRQ_EN_REG);
	writel(val \| GPT_IRQ_ENABLE(timer),
	timer_of_base(to) + GPT_IRQ_EN_REG);
	}

	static void mtk_gpt_resume(struct clock_event_device *clk)
	{
	struct timer_of *to = to_timer_of(clk);

	mtk_gpt_enable_irq(to, TIMER_CLK_EVT);
	}

	static void mtk_gpt_suspend(struct clock_event_device *clk)
	{
	struct timer_of *to = to_timer_of(clk);

	/* Disable all interrupts */
	writel(0x0, timer_of_base(to) + GPT_IRQ_EN_REG);

	/*
	* This is called with interrupts disabled,
	* so we need to ack any interrupt that is pending
	* or for example ATF will prevent a suspend from completing.
	*/
	writel(0x3f, timer_of_base(to) + GPT_IRQ_ACK_REG);
	}

	static struct timer_of to = {
	.flags = TIMER_OF_IRQ \| TIMER_OF_BASE \| TIMER_OF_CLOCK,

	.clkevt = {
	.name = "mtk-clkevt",
	.rating = 300,
	.cpumask = cpu_possible_mask,
	},

	.of_irq = {
	.flags = IRQF_TIMER \| IRQF_IRQPOLL,
	},
	};

	static int __init mtk_cpux_init(struct device_node *node)
	{
	static struct timer_of to_cpux;
	u32 freq, val;
	int ret;

	/*
	* There are per-cpu interrupts for the CPUX General Purpose Timer
	* but since this timer feeds the AArch64 System Timer we can rely
	* on the CPU timer PPIs as well, so we don't declare TIMER_OF_IRQ.
	*/
	to_cpux.flags = TIMER_OF_BASE \| TIMER_OF_CLOCK;
	to_cpux.clkevt.name = "mtk-cpuxgpt";
	to_cpux.clkevt.rating = 10;
	to_cpux.clkevt.cpumask = cpu_possible_mask;
	to_cpux.clkevt.set_state_shutdown = mtk_cpux_clkevt_shutdown;
	to_cpux.clkevt.tick_resume = mtk_cpux_clkevt_resume;

	/* If this fails, bad things are about to happen... */
	ret = timer_of_init(node, &to_cpux);
	if (ret) {
	WARN(1, "Cannot start CPUX timers.\n");
	return ret;
	}

	/*
	* Check if we're given a clock with the right frequency for this
	* timer, otherwise warn but keep going with the setup anyway, as
	* that makes it possible to still boot the kernel, even though
	* it may not work correctly (random lockups, etc).
	* The reason behind this is that having an early UART may not be
	* possible for everyone and this gives a chance to retrieve kmsg
	* for eventual debugging even on consumer devices.
	*/
	freq = timer_of_rate(&to_cpux);
	if (freq > 13000000)
	WARN(1, "Requested unsupported timer frequency %u\n", freq);

	/* Clock input is 26MHz, set DIV2 to achieve 13MHz clock */
	val = mtk_cpux_readl(CPUX_IDX_GLOBAL_CTRL, &to_cpux);
	val &= ~CPUX_CLK_DIV_MASK;
	val \|= CPUX_CLK_DIV2;
	mtk_cpux_writel(val, CPUX_IDX_GLOBAL_CTRL, &to_cpux);

	/* Enable all CPUXGPT timers */
	val = mtk_cpux_readl(CPUX_IDX_GLOBAL_CTRL, &to_cpux);
	mtk_cpux_writel(val \| CPUX_ENABLE, CPUX_IDX_GLOBAL_CTRL, &to_cpux);

	clockevents_config_and_register(&to_cpux.clkevt, timer_of_rate(&to_cpux),
	TIMER_SYNC_TICKS, 0xffffffff);

	return 0;
	}

	static int __init mtk_syst_init(struct device_node *node)
	{
	int ret;

	to.clkevt.features = CLOCK_EVT_FEAT_DYNIRQ \| CLOCK_EVT_FEAT_ONESHOT;
	to.clkevt.set_state_shutdown = mtk_syst_clkevt_shutdown;
	to.clkevt.set_state_oneshot = mtk_syst_clkevt_oneshot;
	to.clkevt.tick_resume = mtk_syst_clkevt_resume;
	to.clkevt.set_next_event = mtk_syst_clkevt_next_event;
	to.of_irq.handler = mtk_syst_handler;

	ret = timer_of_init(node, &to);
	if (ret)
	return ret;

	clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
	TIMER_SYNC_TICKS, 0xffffffff);

	return 0;
	}

	static int __init mtk_gpt_init(struct device_node *node)
	{
	int ret;

	to.clkevt.features = CLOCK_EVT_FEAT_PERIODIC \| CLOCK_EVT_FEAT_ONESHOT;
	to.clkevt.set_state_shutdown = mtk_gpt_clkevt_shutdown;
	to.clkevt.set_state_periodic = mtk_gpt_clkevt_set_periodic;
	to.clkevt.set_state_oneshot = mtk_gpt_clkevt_shutdown;
	to.clkevt.tick_resume = mtk_gpt_clkevt_shutdown;
	to.clkevt.set_next_event = mtk_gpt_clkevt_next_event;
	to.clkevt.suspend = mtk_gpt_suspend;
	to.clkevt.resume = mtk_gpt_resume;
	to.of_irq.handler = mtk_gpt_interrupt;

	ret = timer_of_init(node, &to);
	if (ret)
	return ret;

	/* Configure clock source */
	mtk_gpt_setup(&to, TIMER_CLK_SRC, GPT_CTRL_OP_FREERUN);
	clocksource_mmio_init(timer_of_base(&to) + GPT_CNT_REG(TIMER_CLK_SRC),
	node->name, timer_of_rate(&to), 300, 32,
	clocksource_mmio_readl_up);
	gpt_sched_reg = timer_of_base(&to) + GPT_CNT_REG(TIMER_CLK_SRC);
	sched_clock_register(mtk_gpt_read_sched_clock, 32, timer_of_rate(&to));

	/* Configure clock event */
	mtk_gpt_setup(&to, TIMER_CLK_EVT, GPT_CTRL_OP_REPEAT);
	clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
	TIMER_SYNC_TICKS, 0xffffffff);

	mtk_gpt_enable_irq(&to, TIMER_CLK_EVT);

	return 0;
	}
	TIMER_OF_DECLARE(mtk_mt6577, "mediatek,mt6577-timer", mtk_gpt_init);
	TIMER_OF_DECLARE(mtk_mt6765, "mediatek,mt6765-timer", mtk_syst_init);
	TIMER_OF_DECLARE(mtk_mt6795, "mediatek,mt6795-systimer", mtk_cpux_init);