drivers/clocksource/timer-u300.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (C) 2007-2009 ST-Ericsson AB
  * License terms: GNU General Public License (GPL) version 2
  * Timer COH 901 328, runs the OS timer interrupt.
  * Author: Linus Walleij <linus.walleij@stericsson.com>
  */
 #include <linux/interrupt.h>
 #include <linux/time.h>
 #include <linux/timex.h>
 #include <linux/clockchips.h>
 #include <linux/clocksource.h>
 #include <linux/types.h>
 #include <linux/io.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/irq.h>
 #include <linux/delay.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/sched_clock.h>

 /* Generic stuff */
 #include <asm/mach/map.h>
 #include <asm/mach/time.h>

 /*
  * APP side special timer registers
  * This timer contains four timers which can fire an interrupt each.
  * OS (operating system) timer @ 32768 Hz
  * DD (device driver) timer @ 1 kHz
  * GP1 (general purpose 1) timer @ 1MHz
  * GP2 (general purpose 2) timer @ 1MHz
  */

 /* Reset OS Timer 32bit (-/W) */
 #define U300_TIMER_APP_ROST					(0x0000)
 #define U300_TIMER_APP_ROST_TIMER_RESET				(0x00000000)
 /* Enable OS Timer 32bit (-/W) */
 #define U300_TIMER_APP_EOST					(0x0004)
 #define U300_TIMER_APP_EOST_TIMER_ENABLE			(0x00000000)
 /* Disable OS Timer 32bit (-/W) */
 #define U300_TIMER_APP_DOST					(0x0008)
 #define U300_TIMER_APP_DOST_TIMER_DISABLE			(0x00000000)
 /* OS Timer Mode Register 32bit (-/W) */
 #define U300_TIMER_APP_SOSTM					(0x000c)
 #define U300_TIMER_APP_SOSTM_MODE_CONTINUOUS			(0x00000000)
 #define U300_TIMER_APP_SOSTM_MODE_ONE_SHOT			(0x00000001)
 /* OS Timer Status Register 32bit (R/-) */
 #define U300_TIMER_APP_OSTS					(0x0010)
 #define U300_TIMER_APP_OSTS_TIMER_STATE_MASK			(0x0000000F)
 #define U300_TIMER_APP_OSTS_TIMER_STATE_IDLE			(0x00000001)
 #define U300_TIMER_APP_OSTS_TIMER_STATE_ACTIVE			(0x00000002)
 #define U300_TIMER_APP_OSTS_ENABLE_IND				(0x00000010)
 #define U300_TIMER_APP_OSTS_MODE_MASK				(0x00000020)
 #define U300_TIMER_APP_OSTS_MODE_CONTINUOUS			(0x00000000)
 #define U300_TIMER_APP_OSTS_MODE_ONE_SHOT			(0x00000020)
 #define U300_TIMER_APP_OSTS_IRQ_ENABLED_IND			(0x00000040)
 #define U300_TIMER_APP_OSTS_IRQ_PENDING_IND			(0x00000080)
 /* OS Timer Current Count Register 32bit (R/-) */
 #define U300_TIMER_APP_OSTCC					(0x0014)
 /* OS Timer Terminal Count Register 32bit (R/W) */
 #define U300_TIMER_APP_OSTTC					(0x0018)
 /* OS Timer Interrupt Enable Register 32bit (-/W) */
 #define U300_TIMER_APP_OSTIE					(0x001c)
 #define U300_TIMER_APP_OSTIE_IRQ_DISABLE			(0x00000000)
 #define U300_TIMER_APP_OSTIE_IRQ_ENABLE				(0x00000001)
 /* OS Timer Interrupt Acknowledge Register 32bit (-/W) */
 #define U300_TIMER_APP_OSTIA					(0x0020)
 #define U300_TIMER_APP_OSTIA_IRQ_ACK				(0x00000080)

 /* Reset DD Timer 32bit (-/W) */
 #define U300_TIMER_APP_RDDT					(0x0040)
 #define U300_TIMER_APP_RDDT_TIMER_RESET				(0x00000000)
 /* Enable DD Timer 32bit (-/W) */
 #define U300_TIMER_APP_EDDT					(0x0044)
 #define U300_TIMER_APP_EDDT_TIMER_ENABLE			(0x00000000)
 /* Disable DD Timer 32bit (-/W) */
 #define U300_TIMER_APP_DDDT					(0x0048)
 #define U300_TIMER_APP_DDDT_TIMER_DISABLE			(0x00000000)
 /* DD Timer Mode Register 32bit (-/W) */
 #define U300_TIMER_APP_SDDTM					(0x004c)
 #define U300_TIMER_APP_SDDTM_MODE_CONTINUOUS			(0x00000000)
 #define U300_TIMER_APP_SDDTM_MODE_ONE_SHOT			(0x00000001)
 /* DD Timer Status Register 32bit (R/-) */
 #define U300_TIMER_APP_DDTS					(0x0050)
 #define U300_TIMER_APP_DDTS_TIMER_STATE_MASK			(0x0000000F)
 #define U300_TIMER_APP_DDTS_TIMER_STATE_IDLE			(0x00000001)
 #define U300_TIMER_APP_DDTS_TIMER_STATE_ACTIVE			(0x00000002)
 #define U300_TIMER_APP_DDTS_ENABLE_IND				(0x00000010)
 #define U300_TIMER_APP_DDTS_MODE_MASK				(0x00000020)
 #define U300_TIMER_APP_DDTS_MODE_CONTINUOUS			(0x00000000)
 #define U300_TIMER_APP_DDTS_MODE_ONE_SHOT			(0x00000020)
 #define U300_TIMER_APP_DDTS_IRQ_ENABLED_IND			(0x00000040)
 #define U300_TIMER_APP_DDTS_IRQ_PENDING_IND			(0x00000080)
 /* DD Timer Current Count Register 32bit (R/-) */
 #define U300_TIMER_APP_DDTCC					(0x0054)
 /* DD Timer Terminal Count Register 32bit (R/W) */
 #define U300_TIMER_APP_DDTTC					(0x0058)
 /* DD Timer Interrupt Enable Register 32bit (-/W) */
 #define U300_TIMER_APP_DDTIE					(0x005c)
 #define U300_TIMER_APP_DDTIE_IRQ_DISABLE			(0x00000000)
 #define U300_TIMER_APP_DDTIE_IRQ_ENABLE				(0x00000001)
 /* DD Timer Interrupt Acknowledge Register 32bit (-/W) */
 #define U300_TIMER_APP_DDTIA					(0x0060)
 #define U300_TIMER_APP_DDTIA_IRQ_ACK				(0x00000080)

 /* Reset GP1 Timer 32bit (-/W) */
 #define U300_TIMER_APP_RGPT1					(0x0080)
 #define U300_TIMER_APP_RGPT1_TIMER_RESET			(0x00000000)
 /* Enable GP1 Timer 32bit (-/W) */
 #define U300_TIMER_APP_EGPT1					(0x0084)
 #define U300_TIMER_APP_EGPT1_TIMER_ENABLE			(0x00000000)
 /* Disable GP1 Timer 32bit (-/W) */
 #define U300_TIMER_APP_DGPT1					(0x0088)
 #define U300_TIMER_APP_DGPT1_TIMER_DISABLE			(0x00000000)
 /* GP1 Timer Mode Register 32bit (-/W) */
 #define U300_TIMER_APP_SGPT1M					(0x008c)
 #define U300_TIMER_APP_SGPT1M_MODE_CONTINUOUS			(0x00000000)
 #define U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT			(0x00000001)
 /* GP1 Timer Status Register 32bit (R/-) */
 #define U300_TIMER_APP_GPT1S					(0x0090)
 #define U300_TIMER_APP_GPT1S_TIMER_STATE_MASK			(0x0000000F)
 #define U300_TIMER_APP_GPT1S_TIMER_STATE_IDLE			(0x00000001)
 #define U300_TIMER_APP_GPT1S_TIMER_STATE_ACTIVE			(0x00000002)
 #define U300_TIMER_APP_GPT1S_ENABLE_IND				(0x00000010)
 #define U300_TIMER_APP_GPT1S_MODE_MASK				(0x00000020)
 #define U300_TIMER_APP_GPT1S_MODE_CONTINUOUS			(0x00000000)
 #define U300_TIMER_APP_GPT1S_MODE_ONE_SHOT			(0x00000020)
 #define U300_TIMER_APP_GPT1S_IRQ_ENABLED_IND			(0x00000040)
 #define U300_TIMER_APP_GPT1S_IRQ_PENDING_IND			(0x00000080)
 /* GP1 Timer Current Count Register 32bit (R/-) */
 #define U300_TIMER_APP_GPT1CC					(0x0094)
 /* GP1 Timer Terminal Count Register 32bit (R/W) */
 #define U300_TIMER_APP_GPT1TC					(0x0098)
 /* GP1 Timer Interrupt Enable Register 32bit (-/W) */
 #define U300_TIMER_APP_GPT1IE					(0x009c)
 #define U300_TIMER_APP_GPT1IE_IRQ_DISABLE			(0x00000000)
 #define U300_TIMER_APP_GPT1IE_IRQ_ENABLE			(0x00000001)
 /* GP1 Timer Interrupt Acknowledge Register 32bit (-/W) */
 #define U300_TIMER_APP_GPT1IA					(0x00a0)
 #define U300_TIMER_APP_GPT1IA_IRQ_ACK				(0x00000080)

 /* Reset GP2 Timer 32bit (-/W) */
 #define U300_TIMER_APP_RGPT2					(0x00c0)
 #define U300_TIMER_APP_RGPT2_TIMER_RESET			(0x00000000)
 /* Enable GP2 Timer 32bit (-/W) */
 #define U300_TIMER_APP_EGPT2					(0x00c4)
 #define U300_TIMER_APP_EGPT2_TIMER_ENABLE			(0x00000000)
 /* Disable GP2 Timer 32bit (-/W) */
 #define U300_TIMER_APP_DGPT2					(0x00c8)
 #define U300_TIMER_APP_DGPT2_TIMER_DISABLE			(0x00000000)
 /* GP2 Timer Mode Register 32bit (-/W) */
 #define U300_TIMER_APP_SGPT2M					(0x00cc)
 #define U300_TIMER_APP_SGPT2M_MODE_CONTINUOUS			(0x00000000)
 #define U300_TIMER_APP_SGPT2M_MODE_ONE_SHOT			(0x00000001)
 /* GP2 Timer Status Register 32bit (R/-) */
 #define U300_TIMER_APP_GPT2S					(0x00d0)
 #define U300_TIMER_APP_GPT2S_TIMER_STATE_MASK			(0x0000000F)
 #define U300_TIMER_APP_GPT2S_TIMER_STATE_IDLE			(0x00000001)
 #define U300_TIMER_APP_GPT2S_TIMER_STATE_ACTIVE			(0x00000002)
 #define U300_TIMER_APP_GPT2S_ENABLE_IND				(0x00000010)
 #define U300_TIMER_APP_GPT2S_MODE_MASK				(0x00000020)
 #define U300_TIMER_APP_GPT2S_MODE_CONTINUOUS			(0x00000000)
 #define U300_TIMER_APP_GPT2S_MODE_ONE_SHOT			(0x00000020)
 #define U300_TIMER_APP_GPT2S_IRQ_ENABLED_IND			(0x00000040)
 #define U300_TIMER_APP_GPT2S_IRQ_PENDING_IND			(0x00000080)
 /* GP2 Timer Current Count Register 32bit (R/-) */
 #define U300_TIMER_APP_GPT2CC					(0x00d4)
 /* GP2 Timer Terminal Count Register 32bit (R/W) */
 #define U300_TIMER_APP_GPT2TC					(0x00d8)
 /* GP2 Timer Interrupt Enable Register 32bit (-/W) */
 #define U300_TIMER_APP_GPT2IE					(0x00dc)
 #define U300_TIMER_APP_GPT2IE_IRQ_DISABLE			(0x00000000)
 #define U300_TIMER_APP_GPT2IE_IRQ_ENABLE			(0x00000001)
 /* GP2 Timer Interrupt Acknowledge Register 32bit (-/W) */
 #define U300_TIMER_APP_GPT2IA					(0x00e0)
 #define U300_TIMER_APP_GPT2IA_IRQ_ACK				(0x00000080)

 /* Clock request control register - all four timers */
 #define U300_TIMER_APP_CRC					(0x100)
 #define U300_TIMER_APP_CRC_CLOCK_REQUEST_ENABLE			(0x00000001)

 static void __iomem *u300_timer_base;

 struct u300_clockevent_data {
 	struct clock_event_device cevd;
 	unsigned ticks_per_jiffy;
 };

 /*
  * The u300_set_mode() function is always called first, if we
  * have oneshot timer active, the oneshot scheduling function
  * u300_set_next_event() is called immediately after.
  */
 static void u300_set_mode(enum clock_event_mode mode,
 			  struct clock_event_device *evt)
 {
 	struct u300_clockevent_data *cevdata =
 		container_of(evt, struct u300_clockevent_data, cevd);

 	switch (mode) {
 	case CLOCK_EVT_MODE_PERIODIC:
 		/* Disable interrupts on GPT1 */
 		writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
 		       u300_timer_base + U300_TIMER_APP_GPT1IE);
 		/* Disable GP1 while we're reprogramming it. */
 		writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
 		       u300_timer_base + U300_TIMER_APP_DGPT1);
 		/*
 		 * Set the periodic mode to a certain number of ticks per
 		 * jiffy.
 		 */
 		writel(cevdata->ticks_per_jiffy,
 		       u300_timer_base + U300_TIMER_APP_GPT1TC);
 		/*
 		 * Set continuous mode, so the timer keeps triggering
 		 * interrupts.
 		 */
 		writel(U300_TIMER_APP_SGPT1M_MODE_CONTINUOUS,
 		       u300_timer_base + U300_TIMER_APP_SGPT1M);
 		/* Enable timer interrupts */
 		writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
 		       u300_timer_base + U300_TIMER_APP_GPT1IE);
 		/* Then enable the OS timer again */
 		writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
 		       u300_timer_base + U300_TIMER_APP_EGPT1);
 		break;
 	case CLOCK_EVT_MODE_ONESHOT:
 		/* Just break; here? */
 		/*
 		 * The actual event will be programmed by the next event hook,
 		 * so we just set a dummy value somewhere at the end of the
 		 * universe here.
 		 */
 		/* Disable interrupts on GPT1 */
 		writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
 		       u300_timer_base + U300_TIMER_APP_GPT1IE);
 		/* Disable GP1 while we're reprogramming it. */
 		writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
 		       u300_timer_base + U300_TIMER_APP_DGPT1);
 		/*
 		 * Expire far in the future, u300_set_next_event() will be
 		 * called soon...
 		 */
 		writel(0xFFFFFFFF, u300_timer_base + U300_TIMER_APP_GPT1TC);
 		/* We run one shot per tick here! */
 		writel(U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT,
 		       u300_timer_base + U300_TIMER_APP_SGPT1M);
 		/* Enable interrupts for this timer */
 		writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
 		       u300_timer_base + U300_TIMER_APP_GPT1IE);
 		/* Enable timer */
 		writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
 		       u300_timer_base + U300_TIMER_APP_EGPT1);
 		break;
 	case CLOCK_EVT_MODE_UNUSED:
 	case CLOCK_EVT_MODE_SHUTDOWN:
 		/* Disable interrupts on GP1 */
 		writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
 		       u300_timer_base + U300_TIMER_APP_GPT1IE);
 		/* Disable GP1 */
 		writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
 		       u300_timer_base + U300_TIMER_APP_DGPT1);
 		break;
 	case CLOCK_EVT_MODE_RESUME:
 		/* Ignore this call */
 		break;
 	}
 }

 /*
  * The app timer in one shot mode obviously has to be reprogrammed
  * in EXACTLY this sequence to work properly. Do NOT try to e.g. replace
  * the interrupt disable + timer disable commands with a reset command,
  * it will fail miserably. Apparently (and I found this the hard way)
  * the timer is very sensitive to the instruction order, though you don't
  * get that impression from the data sheet.
  */
 static int u300_set_next_event(unsigned long cycles,
 			       struct clock_event_device *evt)

 {
 	/* Disable interrupts on GPT1 */
 	writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
 	       u300_timer_base + U300_TIMER_APP_GPT1IE);
 	/* Disable GP1 while we're reprogramming it. */
 	writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
 	       u300_timer_base + U300_TIMER_APP_DGPT1);
 	/* Reset the General Purpose timer 1. */
 	writel(U300_TIMER_APP_RGPT1_TIMER_RESET,
 	       u300_timer_base + U300_TIMER_APP_RGPT1);
 	/* IRQ in n * cycles */
 	writel(cycles, u300_timer_base + U300_TIMER_APP_GPT1TC);
 	/*
 	 * We run one shot per tick here! (This is necessary to reconfigure,
 	 * the timer will tilt if you don't!)
 	 */
 	writel(U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT,
 	       u300_timer_base + U300_TIMER_APP_SGPT1M);
 	/* Enable timer interrupts */
 	writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
 	       u300_timer_base + U300_TIMER_APP_GPT1IE);
 	/* Then enable the OS timer again */
 	writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
 	       u300_timer_base + U300_TIMER_APP_EGPT1);
 	return 0;
 }

 static struct u300_clockevent_data u300_clockevent_data = {
 	/* Use general purpose timer 1 as clock event */
 	.cevd = {
 		.name		= "GPT1",
 		/* Reasonably fast and accurate clock event */
 		.rating		= 300,
 		.features	= CLOCK_EVT_FEAT_PERIODIC |
 			CLOCK_EVT_FEAT_ONESHOT,
 		.set_next_event	= u300_set_next_event,
 		.set_mode	= u300_set_mode,
 	},
 };

 /* Clock event timer interrupt handler */
 static irqreturn_t u300_timer_interrupt(int irq, void *dev_id)
 {
 	struct clock_event_device *evt = &u300_clockevent_data.cevd;
 	/* ACK/Clear timer IRQ for the APP GPT1 Timer */

 	writel(U300_TIMER_APP_GPT1IA_IRQ_ACK,
 		u300_timer_base + U300_TIMER_APP_GPT1IA);
 	evt->event_handler(evt);
 	return IRQ_HANDLED;
 }

 static struct irqaction u300_timer_irq = {
 	.name		= "U300 Timer Tick",
 	.flags		= IRQF_TIMER | IRQF_IRQPOLL,
 	.handler	= u300_timer_interrupt,
 };

 /*
  * Override the global weak sched_clock symbol with this
  * local implementation which uses the clocksource to get some
  * better resolution when scheduling the kernel. We accept that
  * this wraps around for now, since it is just a relative time
  * stamp. (Inspired by OMAP implementation.)
  */

 static u64 notrace u300_read_sched_clock(void)
 {
 	return readl(u300_timer_base + U300_TIMER_APP_GPT2CC);
 }

 static unsigned long u300_read_current_timer(void)
 {
 	return readl(u300_timer_base + U300_TIMER_APP_GPT2CC);
 }

 static struct delay_timer u300_delay_timer;

 /*
  * This sets up the system timers, clock source and clock event.
  */
 static void __init u300_timer_init_of(struct device_node *np)
 {
 	unsigned int irq;
 	struct clk *clk;
 	unsigned long rate;

 	u300_timer_base = of_iomap(np, 0);
 	if (!u300_timer_base)
 		panic("could not ioremap system timer\n");

 	/* Get the IRQ for the GP1 timer */
 	irq = irq_of_parse_and_map(np, 2);
 	if (!irq)
 		panic("no IRQ for system timer\n");

 	pr_info("U300 GP1 timer @ base: %p, IRQ: %u\n", u300_timer_base, irq);

 	/* Clock the interrupt controller */
 	clk = of_clk_get(np, 0);
 	BUG_ON(IS_ERR(clk));
 	clk_prepare_enable(clk);
 	rate = clk_get_rate(clk);

 	u300_clockevent_data.ticks_per_jiffy = DIV_ROUND_CLOSEST(rate, HZ);

 	sched_clock_register(u300_read_sched_clock, 32, rate);

 	u300_delay_timer.read_current_timer = &u300_read_current_timer;
 	u300_delay_timer.freq = rate;
 	register_current_timer_delay(&u300_delay_timer);

 	/*
 	 * Disable the "OS" and "DD" timers - these are designed for Symbian!
 	 * Example usage in cnh1601578 cpu subsystem pd_timer_app.c
 	 */
 	writel(U300_TIMER_APP_CRC_CLOCK_REQUEST_ENABLE,
 		u300_timer_base + U300_TIMER_APP_CRC);
 	writel(U300_TIMER_APP_ROST_TIMER_RESET,
 		u300_timer_base + U300_TIMER_APP_ROST);
 	writel(U300_TIMER_APP_DOST_TIMER_DISABLE,
 		u300_timer_base + U300_TIMER_APP_DOST);
 	writel(U300_TIMER_APP_RDDT_TIMER_RESET,
 		u300_timer_base + U300_TIMER_APP_RDDT);
 	writel(U300_TIMER_APP_DDDT_TIMER_DISABLE,
 		u300_timer_base + U300_TIMER_APP_DDDT);

 	/* Reset the General Purpose timer 1. */
 	writel(U300_TIMER_APP_RGPT1_TIMER_RESET,
 		u300_timer_base + U300_TIMER_APP_RGPT1);

 	/* Set up the IRQ handler */
 	setup_irq(irq, &u300_timer_irq);

 	/* Reset the General Purpose timer 2 */
 	writel(U300_TIMER_APP_RGPT2_TIMER_RESET,
 		u300_timer_base + U300_TIMER_APP_RGPT2);
 	/* Set this timer to run around forever */
 	writel(0xFFFFFFFFU, u300_timer_base + U300_TIMER_APP_GPT2TC);
 	/* Set continuous mode so it wraps around */
 	writel(U300_TIMER_APP_SGPT2M_MODE_CONTINUOUS,
 	       u300_timer_base + U300_TIMER_APP_SGPT2M);
 	/* Disable timer interrupts */
 	writel(U300_TIMER_APP_GPT2IE_IRQ_DISABLE,
 		u300_timer_base + U300_TIMER_APP_GPT2IE);
 	/* Then enable the GP2 timer to use as a free running us counter */
 	writel(U300_TIMER_APP_EGPT2_TIMER_ENABLE,
 		u300_timer_base + U300_TIMER_APP_EGPT2);

 	/* Use general purpose timer 2 as clock source */
 	if (clocksource_mmio_init(u300_timer_base + U300_TIMER_APP_GPT2CC,
 			"GPT2", rate, 300, 32, clocksource_mmio_readl_up))
 		pr_err("timer: failed to initialize U300 clock source\n");

 	/* Configure and register the clockevent */
 	clockevents_config_and_register(&u300_clockevent_data.cevd, rate,
 					1, 0xffffffff);

 	/*
 	 * TODO: init and register the rest of the timers too, they can be
 	 * used by hrtimers!
 	 */
 }

 CLOCKSOURCE_OF_DECLARE(u300_timer, "stericsson,u300-apptimer",
 		       u300_timer_init_of);
	/*
	* Copyright (C) 2007-2009 ST-Ericsson AB
	* License terms: GNU General Public License (GPL) version 2
	* Timer COH 901 328, runs the OS timer interrupt.
	* Author: Linus Walleij <linus.walleij@stericsson.com>
	*/
	#include <linux/interrupt.h>
	#include <linux/time.h>
	#include <linux/timex.h>
	#include <linux/clockchips.h>
	#include <linux/clocksource.h>
	#include <linux/types.h>
	#include <linux/io.h>
	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/irq.h>
	#include <linux/delay.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/sched_clock.h>

	/* Generic stuff */
	#include <asm/mach/map.h>
	#include <asm/mach/time.h>

	/*
	* APP side special timer registers
	* This timer contains four timers which can fire an interrupt each.
	* OS (operating system) timer @ 32768 Hz
	* DD (device driver) timer @ 1 kHz
	* GP1 (general purpose 1) timer @ 1MHz
	* GP2 (general purpose 2) timer @ 1MHz
	*/

	/* Reset OS Timer 32bit (-/W) */
	#define U300_TIMER_APP_ROST (0x0000)
	#define U300_TIMER_APP_ROST_TIMER_RESET (0x00000000)
	/* Enable OS Timer 32bit (-/W) */
	#define U300_TIMER_APP_EOST (0x0004)
	#define U300_TIMER_APP_EOST_TIMER_ENABLE (0x00000000)
	/* Disable OS Timer 32bit (-/W) */
	#define U300_TIMER_APP_DOST (0x0008)
	#define U300_TIMER_APP_DOST_TIMER_DISABLE (0x00000000)
	/* OS Timer Mode Register 32bit (-/W) */
	#define U300_TIMER_APP_SOSTM (0x000c)
	#define U300_TIMER_APP_SOSTM_MODE_CONTINUOUS (0x00000000)
	#define U300_TIMER_APP_SOSTM_MODE_ONE_SHOT (0x00000001)
	/* OS Timer Status Register 32bit (R/-) */
	#define U300_TIMER_APP_OSTS (0x0010)
	#define U300_TIMER_APP_OSTS_TIMER_STATE_MASK (0x0000000F)
	#define U300_TIMER_APP_OSTS_TIMER_STATE_IDLE (0x00000001)
	#define U300_TIMER_APP_OSTS_TIMER_STATE_ACTIVE (0x00000002)
	#define U300_TIMER_APP_OSTS_ENABLE_IND (0x00000010)
	#define U300_TIMER_APP_OSTS_MODE_MASK (0x00000020)
	#define U300_TIMER_APP_OSTS_MODE_CONTINUOUS (0x00000000)
	#define U300_TIMER_APP_OSTS_MODE_ONE_SHOT (0x00000020)
	#define U300_TIMER_APP_OSTS_IRQ_ENABLED_IND (0x00000040)
	#define U300_TIMER_APP_OSTS_IRQ_PENDING_IND (0x00000080)
	/* OS Timer Current Count Register 32bit (R/-) */
	#define U300_TIMER_APP_OSTCC (0x0014)
	/* OS Timer Terminal Count Register 32bit (R/W) */
	#define U300_TIMER_APP_OSTTC (0x0018)
	/* OS Timer Interrupt Enable Register 32bit (-/W) */
	#define U300_TIMER_APP_OSTIE (0x001c)
	#define U300_TIMER_APP_OSTIE_IRQ_DISABLE (0x00000000)
	#define U300_TIMER_APP_OSTIE_IRQ_ENABLE (0x00000001)
	/* OS Timer Interrupt Acknowledge Register 32bit (-/W) */
	#define U300_TIMER_APP_OSTIA (0x0020)
	#define U300_TIMER_APP_OSTIA_IRQ_ACK (0x00000080)

	/* Reset DD Timer 32bit (-/W) */
	#define U300_TIMER_APP_RDDT (0x0040)
	#define U300_TIMER_APP_RDDT_TIMER_RESET (0x00000000)
	/* Enable DD Timer 32bit (-/W) */
	#define U300_TIMER_APP_EDDT (0x0044)
	#define U300_TIMER_APP_EDDT_TIMER_ENABLE (0x00000000)
	/* Disable DD Timer 32bit (-/W) */
	#define U300_TIMER_APP_DDDT (0x0048)
	#define U300_TIMER_APP_DDDT_TIMER_DISABLE (0x00000000)
	/* DD Timer Mode Register 32bit (-/W) */
	#define U300_TIMER_APP_SDDTM (0x004c)
	#define U300_TIMER_APP_SDDTM_MODE_CONTINUOUS (0x00000000)
	#define U300_TIMER_APP_SDDTM_MODE_ONE_SHOT (0x00000001)
	/* DD Timer Status Register 32bit (R/-) */
	#define U300_TIMER_APP_DDTS (0x0050)
	#define U300_TIMER_APP_DDTS_TIMER_STATE_MASK (0x0000000F)
	#define U300_TIMER_APP_DDTS_TIMER_STATE_IDLE (0x00000001)
	#define U300_TIMER_APP_DDTS_TIMER_STATE_ACTIVE (0x00000002)
	#define U300_TIMER_APP_DDTS_ENABLE_IND (0x00000010)
	#define U300_TIMER_APP_DDTS_MODE_MASK (0x00000020)
	#define U300_TIMER_APP_DDTS_MODE_CONTINUOUS (0x00000000)
	#define U300_TIMER_APP_DDTS_MODE_ONE_SHOT (0x00000020)
	#define U300_TIMER_APP_DDTS_IRQ_ENABLED_IND (0x00000040)
	#define U300_TIMER_APP_DDTS_IRQ_PENDING_IND (0x00000080)
	/* DD Timer Current Count Register 32bit (R/-) */
	#define U300_TIMER_APP_DDTCC (0x0054)
	/* DD Timer Terminal Count Register 32bit (R/W) */
	#define U300_TIMER_APP_DDTTC (0x0058)
	/* DD Timer Interrupt Enable Register 32bit (-/W) */
	#define U300_TIMER_APP_DDTIE (0x005c)
	#define U300_TIMER_APP_DDTIE_IRQ_DISABLE (0x00000000)
	#define U300_TIMER_APP_DDTIE_IRQ_ENABLE (0x00000001)
	/* DD Timer Interrupt Acknowledge Register 32bit (-/W) */
	#define U300_TIMER_APP_DDTIA (0x0060)
	#define U300_TIMER_APP_DDTIA_IRQ_ACK (0x00000080)

	/* Reset GP1 Timer 32bit (-/W) */
	#define U300_TIMER_APP_RGPT1 (0x0080)
	#define U300_TIMER_APP_RGPT1_TIMER_RESET (0x00000000)
	/* Enable GP1 Timer 32bit (-/W) */
	#define U300_TIMER_APP_EGPT1 (0x0084)
	#define U300_TIMER_APP_EGPT1_TIMER_ENABLE (0x00000000)
	/* Disable GP1 Timer 32bit (-/W) */
	#define U300_TIMER_APP_DGPT1 (0x0088)
	#define U300_TIMER_APP_DGPT1_TIMER_DISABLE (0x00000000)
	/* GP1 Timer Mode Register 32bit (-/W) */
	#define U300_TIMER_APP_SGPT1M (0x008c)
	#define U300_TIMER_APP_SGPT1M_MODE_CONTINUOUS (0x00000000)
	#define U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT (0x00000001)
	/* GP1 Timer Status Register 32bit (R/-) */
	#define U300_TIMER_APP_GPT1S (0x0090)
	#define U300_TIMER_APP_GPT1S_TIMER_STATE_MASK (0x0000000F)
	#define U300_TIMER_APP_GPT1S_TIMER_STATE_IDLE (0x00000001)
	#define U300_TIMER_APP_GPT1S_TIMER_STATE_ACTIVE (0x00000002)
	#define U300_TIMER_APP_GPT1S_ENABLE_IND (0x00000010)
	#define U300_TIMER_APP_GPT1S_MODE_MASK (0x00000020)
	#define U300_TIMER_APP_GPT1S_MODE_CONTINUOUS (0x00000000)
	#define U300_TIMER_APP_GPT1S_MODE_ONE_SHOT (0x00000020)
	#define U300_TIMER_APP_GPT1S_IRQ_ENABLED_IND (0x00000040)
	#define U300_TIMER_APP_GPT1S_IRQ_PENDING_IND (0x00000080)
	/* GP1 Timer Current Count Register 32bit (R/-) */
	#define U300_TIMER_APP_GPT1CC (0x0094)
	/* GP1 Timer Terminal Count Register 32bit (R/W) */
	#define U300_TIMER_APP_GPT1TC (0x0098)
	/* GP1 Timer Interrupt Enable Register 32bit (-/W) */
	#define U300_TIMER_APP_GPT1IE (0x009c)
	#define U300_TIMER_APP_GPT1IE_IRQ_DISABLE (0x00000000)
	#define U300_TIMER_APP_GPT1IE_IRQ_ENABLE (0x00000001)
	/* GP1 Timer Interrupt Acknowledge Register 32bit (-/W) */
	#define U300_TIMER_APP_GPT1IA (0x00a0)
	#define U300_TIMER_APP_GPT1IA_IRQ_ACK (0x00000080)

	/* Reset GP2 Timer 32bit (-/W) */
	#define U300_TIMER_APP_RGPT2 (0x00c0)
	#define U300_TIMER_APP_RGPT2_TIMER_RESET (0x00000000)
	/* Enable GP2 Timer 32bit (-/W) */
	#define U300_TIMER_APP_EGPT2 (0x00c4)
	#define U300_TIMER_APP_EGPT2_TIMER_ENABLE (0x00000000)
	/* Disable GP2 Timer 32bit (-/W) */
	#define U300_TIMER_APP_DGPT2 (0x00c8)
	#define U300_TIMER_APP_DGPT2_TIMER_DISABLE (0x00000000)
	/* GP2 Timer Mode Register 32bit (-/W) */
	#define U300_TIMER_APP_SGPT2M (0x00cc)
	#define U300_TIMER_APP_SGPT2M_MODE_CONTINUOUS (0x00000000)
	#define U300_TIMER_APP_SGPT2M_MODE_ONE_SHOT (0x00000001)
	/* GP2 Timer Status Register 32bit (R/-) */
	#define U300_TIMER_APP_GPT2S (0x00d0)
	#define U300_TIMER_APP_GPT2S_TIMER_STATE_MASK (0x0000000F)
	#define U300_TIMER_APP_GPT2S_TIMER_STATE_IDLE (0x00000001)
	#define U300_TIMER_APP_GPT2S_TIMER_STATE_ACTIVE (0x00000002)
	#define U300_TIMER_APP_GPT2S_ENABLE_IND (0x00000010)
	#define U300_TIMER_APP_GPT2S_MODE_MASK (0x00000020)
	#define U300_TIMER_APP_GPT2S_MODE_CONTINUOUS (0x00000000)
	#define U300_TIMER_APP_GPT2S_MODE_ONE_SHOT (0x00000020)
	#define U300_TIMER_APP_GPT2S_IRQ_ENABLED_IND (0x00000040)
	#define U300_TIMER_APP_GPT2S_IRQ_PENDING_IND (0x00000080)
	/* GP2 Timer Current Count Register 32bit (R/-) */
	#define U300_TIMER_APP_GPT2CC (0x00d4)
	/* GP2 Timer Terminal Count Register 32bit (R/W) */
	#define U300_TIMER_APP_GPT2TC (0x00d8)
	/* GP2 Timer Interrupt Enable Register 32bit (-/W) */
	#define U300_TIMER_APP_GPT2IE (0x00dc)
	#define U300_TIMER_APP_GPT2IE_IRQ_DISABLE (0x00000000)
	#define U300_TIMER_APP_GPT2IE_IRQ_ENABLE (0x00000001)
	/* GP2 Timer Interrupt Acknowledge Register 32bit (-/W) */
	#define U300_TIMER_APP_GPT2IA (0x00e0)
	#define U300_TIMER_APP_GPT2IA_IRQ_ACK (0x00000080)

	/* Clock request control register - all four timers */
	#define U300_TIMER_APP_CRC (0x100)
	#define U300_TIMER_APP_CRC_CLOCK_REQUEST_ENABLE (0x00000001)

	static void __iomem *u300_timer_base;

	struct u300_clockevent_data {
	struct clock_event_device cevd;
	unsigned ticks_per_jiffy;
	};

	/*
	* The u300_set_mode() function is always called first, if we
	* have oneshot timer active, the oneshot scheduling function
	* u300_set_next_event() is called immediately after.
	*/
	static void u300_set_mode(enum clock_event_mode mode,
	struct clock_event_device *evt)
	{
	struct u300_clockevent_data *cevdata =
	container_of(evt, struct u300_clockevent_data, cevd);

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
	/* Disable interrupts on GPT1 */
	writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
	u300_timer_base + U300_TIMER_APP_GPT1IE);
	/* Disable GP1 while we're reprogramming it. */
	writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
	u300_timer_base + U300_TIMER_APP_DGPT1);
	/*
	* Set the periodic mode to a certain number of ticks per
	* jiffy.
	*/
	writel(cevdata->ticks_per_jiffy,
	u300_timer_base + U300_TIMER_APP_GPT1TC);
	/*
	* Set continuous mode, so the timer keeps triggering
	* interrupts.
	*/
	writel(U300_TIMER_APP_SGPT1M_MODE_CONTINUOUS,
	u300_timer_base + U300_TIMER_APP_SGPT1M);
	/* Enable timer interrupts */
	writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
	u300_timer_base + U300_TIMER_APP_GPT1IE);
	/* Then enable the OS timer again */
	writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
	u300_timer_base + U300_TIMER_APP_EGPT1);
	break;
	case CLOCK_EVT_MODE_ONESHOT:
	/* Just break; here? */
	/*
	* The actual event will be programmed by the next event hook,
	* so we just set a dummy value somewhere at the end of the
	* universe here.
	*/
	/* Disable interrupts on GPT1 */
	writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
	u300_timer_base + U300_TIMER_APP_GPT1IE);
	/* Disable GP1 while we're reprogramming it. */
	writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
	u300_timer_base + U300_TIMER_APP_DGPT1);
	/*
	* Expire far in the future, u300_set_next_event() will be
	* called soon...
	*/
	writel(0xFFFFFFFF, u300_timer_base + U300_TIMER_APP_GPT1TC);
	/* We run one shot per tick here! */
	writel(U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT,
	u300_timer_base + U300_TIMER_APP_SGPT1M);
	/* Enable interrupts for this timer */
	writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
	u300_timer_base + U300_TIMER_APP_GPT1IE);
	/* Enable timer */
	writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
	u300_timer_base + U300_TIMER_APP_EGPT1);
	break;
	case CLOCK_EVT_MODE_UNUSED:
	case CLOCK_EVT_MODE_SHUTDOWN:
	/* Disable interrupts on GP1 */
	writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
	u300_timer_base + U300_TIMER_APP_GPT1IE);
	/* Disable GP1 */
	writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
	u300_timer_base + U300_TIMER_APP_DGPT1);
	break;
	case CLOCK_EVT_MODE_RESUME:
	/* Ignore this call */
	break;
	}
	}

	/*
	* The app timer in one shot mode obviously has to be reprogrammed
	* in EXACTLY this sequence to work properly. Do NOT try to e.g. replace
	* the interrupt disable + timer disable commands with a reset command,
	* it will fail miserably. Apparently (and I found this the hard way)
	* the timer is very sensitive to the instruction order, though you don't
	* get that impression from the data sheet.
	*/
	static int u300_set_next_event(unsigned long cycles,
	struct clock_event_device *evt)

	{
	/* Disable interrupts on GPT1 */
	writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
	u300_timer_base + U300_TIMER_APP_GPT1IE);
	/* Disable GP1 while we're reprogramming it. */
	writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
	u300_timer_base + U300_TIMER_APP_DGPT1);
	/* Reset the General Purpose timer 1. */
	writel(U300_TIMER_APP_RGPT1_TIMER_RESET,
	u300_timer_base + U300_TIMER_APP_RGPT1);
	/* IRQ in n * cycles */
	writel(cycles, u300_timer_base + U300_TIMER_APP_GPT1TC);
	/*
	* We run one shot per tick here! (This is necessary to reconfigure,
	* the timer will tilt if you don't!)
	*/
	writel(U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT,
	u300_timer_base + U300_TIMER_APP_SGPT1M);
	/* Enable timer interrupts */
	writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
	u300_timer_base + U300_TIMER_APP_GPT1IE);
	/* Then enable the OS timer again */
	writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
	u300_timer_base + U300_TIMER_APP_EGPT1);
	return 0;
	}

	static struct u300_clockevent_data u300_clockevent_data = {
	/* Use general purpose timer 1 as clock event */
	.cevd = {
	.name = "GPT1",
	/* Reasonably fast and accurate clock event */
	.rating = 300,
	.features = CLOCK_EVT_FEAT_PERIODIC \|
	CLOCK_EVT_FEAT_ONESHOT,
	.set_next_event = u300_set_next_event,
	.set_mode = u300_set_mode,
	},
	};

	/* Clock event timer interrupt handler */
	static irqreturn_t u300_timer_interrupt(int irq, void *dev_id)
	{
	struct clock_event_device *evt = &u300_clockevent_data.cevd;
	/* ACK/Clear timer IRQ for the APP GPT1 Timer */

	writel(U300_TIMER_APP_GPT1IA_IRQ_ACK,
	u300_timer_base + U300_TIMER_APP_GPT1IA);
	evt->event_handler(evt);
	return IRQ_HANDLED;
	}

	static struct irqaction u300_timer_irq = {
	.name = "U300 Timer Tick",
	.flags = IRQF_TIMER \| IRQF_IRQPOLL,
	.handler = u300_timer_interrupt,
	};

	/*
	* Override the global weak sched_clock symbol with this
	* local implementation which uses the clocksource to get some
	* better resolution when scheduling the kernel. We accept that
	* this wraps around for now, since it is just a relative time
	* stamp. (Inspired by OMAP implementation.)
	*/

	static u64 notrace u300_read_sched_clock(void)
	{
	return readl(u300_timer_base + U300_TIMER_APP_GPT2CC);
	}

	static unsigned long u300_read_current_timer(void)
	{
	return readl(u300_timer_base + U300_TIMER_APP_GPT2CC);
	}

	static struct delay_timer u300_delay_timer;

	/*
	* This sets up the system timers, clock source and clock event.
	*/
	static void __init u300_timer_init_of(struct device_node *np)
	{
	unsigned int irq;
	struct clk *clk;
	unsigned long rate;

	u300_timer_base = of_iomap(np, 0);
	if (!u300_timer_base)
	panic("could not ioremap system timer\n");

	/* Get the IRQ for the GP1 timer */
	irq = irq_of_parse_and_map(np, 2);
	if (!irq)
	panic("no IRQ for system timer\n");

	pr_info("U300 GP1 timer @ base: %p, IRQ: %u\n", u300_timer_base, irq);

	/* Clock the interrupt controller */
	clk = of_clk_get(np, 0);
	BUG_ON(IS_ERR(clk));
	clk_prepare_enable(clk);
	rate = clk_get_rate(clk);

	u300_clockevent_data.ticks_per_jiffy = DIV_ROUND_CLOSEST(rate, HZ);

	sched_clock_register(u300_read_sched_clock, 32, rate);

	u300_delay_timer.read_current_timer = &u300_read_current_timer;
	u300_delay_timer.freq = rate;
	register_current_timer_delay(&u300_delay_timer);

	/*
	* Disable the "OS" and "DD" timers - these are designed for Symbian!
	* Example usage in cnh1601578 cpu subsystem pd_timer_app.c
	*/
	writel(U300_TIMER_APP_CRC_CLOCK_REQUEST_ENABLE,
	u300_timer_base + U300_TIMER_APP_CRC);
	writel(U300_TIMER_APP_ROST_TIMER_RESET,
	u300_timer_base + U300_TIMER_APP_ROST);
	writel(U300_TIMER_APP_DOST_TIMER_DISABLE,
	u300_timer_base + U300_TIMER_APP_DOST);
	writel(U300_TIMER_APP_RDDT_TIMER_RESET,
	u300_timer_base + U300_TIMER_APP_RDDT);
	writel(U300_TIMER_APP_DDDT_TIMER_DISABLE,
	u300_timer_base + U300_TIMER_APP_DDDT);

	/* Reset the General Purpose timer 1. */
	writel(U300_TIMER_APP_RGPT1_TIMER_RESET,
	u300_timer_base + U300_TIMER_APP_RGPT1);

	/* Set up the IRQ handler */
	setup_irq(irq, &u300_timer_irq);

	/* Reset the General Purpose timer 2 */
	writel(U300_TIMER_APP_RGPT2_TIMER_RESET,
	u300_timer_base + U300_TIMER_APP_RGPT2);
	/* Set this timer to run around forever */
	writel(0xFFFFFFFFU, u300_timer_base + U300_TIMER_APP_GPT2TC);
	/* Set continuous mode so it wraps around */
	writel(U300_TIMER_APP_SGPT2M_MODE_CONTINUOUS,
	u300_timer_base + U300_TIMER_APP_SGPT2M);
	/* Disable timer interrupts */
	writel(U300_TIMER_APP_GPT2IE_IRQ_DISABLE,
	u300_timer_base + U300_TIMER_APP_GPT2IE);
	/* Then enable the GP2 timer to use as a free running us counter */
	writel(U300_TIMER_APP_EGPT2_TIMER_ENABLE,
	u300_timer_base + U300_TIMER_APP_EGPT2);

	/* Use general purpose timer 2 as clock source */
	if (clocksource_mmio_init(u300_timer_base + U300_TIMER_APP_GPT2CC,
	"GPT2", rate, 300, 32, clocksource_mmio_readl_up))
	pr_err("timer: failed to initialize U300 clock source\n");

	/* Configure and register the clockevent */
	clockevents_config_and_register(&u300_clockevent_data.cevd, rate,
	1, 0xffffffff);

	/*
	* TODO: init and register the rest of the timers too, they can be
	* used by hrtimers!
	*/
	}

	CLOCKSOURCE_OF_DECLARE(u300_timer, "stericsson,u300-apptimer",
	u300_timer_init_of);