arch/arm/mach-omap1/time.c - maze/linux - Git at Google

 /*
  * linux/arch/arm/mach-omap1/time.c
  *
  * OMAP Timers
  *
  * Copyright (C) 2004 Nokia Corporation
  * Partial timer rewrite and additional dynamic tick timer support by
  * Tony Lindgen <tony@atomide.com> and
  * Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
  *
  * MPU timer code based on the older MPU timer code for OMAP
  * Copyright (C) 2000 RidgeRun, Inc.
  * Author: Greg Lonnon <glonnon@ridgerun.com>
  *
  * 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.
  *
  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
  * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * You should have received a copy of the  GNU General Public License along
  * with this program; if not, write  to the Free Software Foundation, Inc.,
  * 675 Mass Ave, Cambridge, MA 02139, USA.
  */

 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/sched.h>
 #include <linux/spinlock.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/clocksource.h>
 #include <linux/clockchips.h>

 #include <asm/system.h>
 #include <asm/hardware.h>
 #include <asm/io.h>
 #include <asm/leds.h>
 #include <asm/irq.h>
 #include <asm/mach/irq.h>
 #include <asm/mach/time.h>


 #define OMAP_MPU_TIMER_BASE		OMAP_MPU_TIMER1_BASE
 #define OMAP_MPU_TIMER_OFFSET		0x100

 /* cycles to nsec conversions taken from arch/i386/kernel/timers/timer_tsc.c,
  * converted to use kHz by Kevin Hilman */
 /* convert from cycles(64bits) => nanoseconds (64bits)
  *  basic equation:
  *		ns = cycles / (freq / ns_per_sec)
  *		ns = cycles * (ns_per_sec / freq)
  *		ns = cycles * (10^9 / (cpu_khz * 10^3))
  *		ns = cycles * (10^6 / cpu_khz)
  *
  *	Then we use scaling math (suggested by george at mvista.com) to get:
  *		ns = cycles * (10^6 * SC / cpu_khz / SC
  *		ns = cycles * cyc2ns_scale / SC
  *
  *	And since SC is a constant power of two, we can convert the div
  *  into a shift.
  *			-johnstul at us.ibm.com "math is hard, lets go shopping!"
  */
 static unsigned long cyc2ns_scale;
 #define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */

 static inline void set_cyc2ns_scale(unsigned long cpu_khz)
 {
 	cyc2ns_scale = (1000000 << CYC2NS_SCALE_FACTOR)/cpu_khz;
 }

 static inline unsigned long long cycles_2_ns(unsigned long long cyc)
 {
 	return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
 }


 typedef struct {
 	u32 cntl;			/* CNTL_TIMER, R/W */
 	u32 load_tim;			/* LOAD_TIM,   W */
 	u32 read_tim;			/* READ_TIM,   R */
 } omap_mpu_timer_regs_t;

 #define omap_mpu_timer_base(n)						\
 ((volatile omap_mpu_timer_regs_t*)IO_ADDRESS(OMAP_MPU_TIMER_BASE +	\
 				 (n)*OMAP_MPU_TIMER_OFFSET))

 static inline unsigned long omap_mpu_timer_read(int nr)
 {
 	volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
 	return timer->read_tim;
 }

 static inline void omap_mpu_set_autoreset(int nr)
 {
 	volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);

 	timer->cntl = timer->cntl | MPU_TIMER_AR;
 }

 static inline void omap_mpu_remove_autoreset(int nr)
 {
 	volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);

 	timer->cntl = timer->cntl & ~MPU_TIMER_AR;
 }

 static inline void omap_mpu_timer_start(int nr, unsigned long load_val,
 					int autoreset)
 {
 	volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
 	unsigned int timerflags = (MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_ST);

 	if (autoreset) timerflags |= MPU_TIMER_AR;

 	timer->cntl = MPU_TIMER_CLOCK_ENABLE;
 	udelay(1);
 	timer->load_tim = load_val;
         udelay(1);
 	timer->cntl = timerflags;
 }

 /*
  * ---------------------------------------------------------------------------
  * MPU timer 1 ... count down to zero, interrupt, reload
  * ---------------------------------------------------------------------------
  */
 static int omap_mpu_set_next_event(unsigned long cycles,
 				    struct clock_event_device *evt)
 {
 	omap_mpu_timer_start(0, cycles, 0);
 	return 0;
 }

 static void omap_mpu_set_mode(enum clock_event_mode mode,
 			      struct clock_event_device *evt)
 {
 	switch (mode) {
 	case CLOCK_EVT_MODE_PERIODIC:
 		omap_mpu_set_autoreset(0);
 		break;
 	case CLOCK_EVT_MODE_ONESHOT:
 		omap_mpu_remove_autoreset(0);
 		break;
 	case CLOCK_EVT_MODE_UNUSED:
 	case CLOCK_EVT_MODE_SHUTDOWN:
 		break;
 	}
 }

 static struct clock_event_device clockevent_mpu_timer1 = {
 	.name		= "mpu_timer1",
 	.features       = CLOCK_EVT_FEAT_PERIODIC, CLOCK_EVT_FEAT_ONESHOT,
 	.shift		= 32,
 	.set_next_event	= omap_mpu_set_next_event,
 	.set_mode	= omap_mpu_set_mode,
 };

 static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id)
 {
 	struct clock_event_device *evt = &clockevent_mpu_timer1;

 	evt->event_handler(evt);

 	return IRQ_HANDLED;
 }

 static struct irqaction omap_mpu_timer1_irq = {
 	.name		= "mpu_timer1",
 	.flags		= IRQF_DISABLED | IRQF_TIMER,
 	.handler	= omap_mpu_timer1_interrupt,
 };

 static __init void omap_init_mpu_timer(unsigned long rate)
 {
 	set_cyc2ns_scale(rate / 1000);

 	setup_irq(INT_TIMER1, &omap_mpu_timer1_irq);
 	omap_mpu_timer_start(0, (rate / HZ) - 1, 1);

 	clockevent_mpu_timer1.mult = div_sc(rate, NSEC_PER_SEC,
 					    clockevent_mpu_timer1.shift);
 	clockevent_mpu_timer1.max_delta_ns =
 		clockevent_delta2ns(-1, &clockevent_mpu_timer1);
 	clockevent_mpu_timer1.min_delta_ns =
 		clockevent_delta2ns(1, &clockevent_mpu_timer1);

 	clockevent_mpu_timer1.cpumask = cpumask_of_cpu(0);
 	clockevents_register_device(&clockevent_mpu_timer1);
 }


 /*
  * ---------------------------------------------------------------------------
  * MPU timer 2 ... free running 32-bit clock source and scheduler clock
  * ---------------------------------------------------------------------------
  */

 static unsigned long omap_mpu_timer2_overflows;

 static irqreturn_t omap_mpu_timer2_interrupt(int irq, void *dev_id)
 {
 	omap_mpu_timer2_overflows++;
 	return IRQ_HANDLED;
 }

 static struct irqaction omap_mpu_timer2_irq = {
 	.name		= "mpu_timer2",
 	.flags		= IRQF_DISABLED,
 	.handler	= omap_mpu_timer2_interrupt,
 };

 static cycle_t mpu_read(void)
 {
 	return ~omap_mpu_timer_read(1);
 }

 static struct clocksource clocksource_mpu = {
 	.name		= "mpu_timer2",
 	.rating		= 300,
 	.read		= mpu_read,
 	.mask		= CLOCKSOURCE_MASK(32),
 	.shift		= 24,
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };

 static void __init omap_init_clocksource(unsigned long rate)
 {
 	static char err[] __initdata = KERN_ERR
 			"%s: can't register clocksource!\n";

 	clocksource_mpu.mult
 		= clocksource_khz2mult(rate/1000, clocksource_mpu.shift);

 	setup_irq(INT_TIMER2, &omap_mpu_timer2_irq);
 	omap_mpu_timer_start(1, ~0, 1);

 	if (clocksource_register(&clocksource_mpu))
 		printk(err, clocksource_mpu.name);
 }


 /*
  * Scheduler clock - returns current time in nanosec units.
  */
 unsigned long long sched_clock(void)
 {
 	unsigned long ticks = 0 - omap_mpu_timer_read(1);
 	unsigned long long ticks64;

 	ticks64 = omap_mpu_timer2_overflows;
 	ticks64 <<= 32;
 	ticks64 |= ticks;

 	return cycles_2_ns(ticks64);
 }

 /*
  * ---------------------------------------------------------------------------
  * Timer initialization
  * ---------------------------------------------------------------------------
  */
 static void __init omap_timer_init(void)
 {
 	struct clk	*ck_ref = clk_get(NULL, "ck_ref");
 	unsigned long	rate;

 	BUG_ON(IS_ERR(ck_ref));

 	rate = clk_get_rate(ck_ref);
 	clk_put(ck_ref);

 	/* PTV = 0 */
 	rate /= 2;

 	omap_init_mpu_timer(rate);
 	omap_init_clocksource(rate);
 }

 struct sys_timer omap_timer = {
 	.init		= omap_timer_init,
 };
	/*
	* linux/arch/arm/mach-omap1/time.c
	*
	* OMAP Timers
	*
	* Copyright (C) 2004 Nokia Corporation
	* Partial timer rewrite and additional dynamic tick timer support by
	* Tony Lindgen <tony@atomide.com> and
	* Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
	*
	* MPU timer code based on the older MPU timer code for OMAP
	* Copyright (C) 2000 RidgeRun, Inc.
	* Author: Greg Lonnon <glonnon@ridgerun.com>
	*
	* 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.
	*
	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
	* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
	* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
	* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*
	* You should have received a copy of the GNU General Public License along
	* with this program; if not, write to the Free Software Foundation, Inc.,
	* 675 Mass Ave, Cambridge, MA 02139, USA.
	*/

	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/delay.h>
	#include <linux/interrupt.h>
	#include <linux/sched.h>
	#include <linux/spinlock.h>
	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/clocksource.h>
	#include <linux/clockchips.h>

	#include <asm/system.h>
	#include <asm/hardware.h>
	#include <asm/io.h>
	#include <asm/leds.h>
	#include <asm/irq.h>
	#include <asm/mach/irq.h>
	#include <asm/mach/time.h>


	#define OMAP_MPU_TIMER_BASE OMAP_MPU_TIMER1_BASE
	#define OMAP_MPU_TIMER_OFFSET 0x100

	/* cycles to nsec conversions taken from arch/i386/kernel/timers/timer_tsc.c,
	* converted to use kHz by Kevin Hilman */
	/* convert from cycles(64bits) => nanoseconds (64bits)
	* basic equation:
	* ns = cycles / (freq / ns_per_sec)
	* ns = cycles * (ns_per_sec / freq)
	* ns = cycles * (10^9 / (cpu_khz * 10^3))
	* ns = cycles * (10^6 / cpu_khz)
	*
	* Then we use scaling math (suggested by george at mvista.com) to get:
	* ns = cycles * (10^6 * SC / cpu_khz / SC
	* ns = cycles * cyc2ns_scale / SC
	*
	* And since SC is a constant power of two, we can convert the div
	* into a shift.
	* -johnstul at us.ibm.com "math is hard, lets go shopping!"
	*/
	static unsigned long cyc2ns_scale;
	#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */

	static inline void set_cyc2ns_scale(unsigned long cpu_khz)
	{
	cyc2ns_scale = (1000000 << CYC2NS_SCALE_FACTOR)/cpu_khz;
	}

	static inline unsigned long long cycles_2_ns(unsigned long long cyc)
	{
	return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
	}


	typedef struct {
	u32 cntl; /* CNTL_TIMER, R/W */
	u32 load_tim; /* LOAD_TIM, W */
	u32 read_tim; /* READ_TIM, R */
	} omap_mpu_timer_regs_t;

	#define omap_mpu_timer_base(n) \
	((volatile omap_mpu_timer_regs_t*)IO_ADDRESS(OMAP_MPU_TIMER_BASE + \
	(n)*OMAP_MPU_TIMER_OFFSET))

	static inline unsigned long omap_mpu_timer_read(int nr)
	{
	volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
	return timer->read_tim;
	}

	static inline void omap_mpu_set_autoreset(int nr)
	{
	volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);

	timer->cntl = timer->cntl \| MPU_TIMER_AR;
	}

	static inline void omap_mpu_remove_autoreset(int nr)
	{
	volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);

	timer->cntl = timer->cntl & ~MPU_TIMER_AR;
	}

	static inline void omap_mpu_timer_start(int nr, unsigned long load_val,
	int autoreset)
	{
	volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
	unsigned int timerflags = (MPU_TIMER_CLOCK_ENABLE \| MPU_TIMER_ST);

	if (autoreset) timerflags \|= MPU_TIMER_AR;

	timer->cntl = MPU_TIMER_CLOCK_ENABLE;
	udelay(1);
	timer->load_tim = load_val;
	udelay(1);
	timer->cntl = timerflags;
	}

	/*
	* ---------------------------------------------------------------------------
	* MPU timer 1 ... count down to zero, interrupt, reload
	* ---------------------------------------------------------------------------
	*/
	static int omap_mpu_set_next_event(unsigned long cycles,
	struct clock_event_device *evt)
	{
	omap_mpu_timer_start(0, cycles, 0);
	return 0;
	}

	static void omap_mpu_set_mode(enum clock_event_mode mode,
	struct clock_event_device *evt)
	{
	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
	omap_mpu_set_autoreset(0);
	break;
	case CLOCK_EVT_MODE_ONESHOT:
	omap_mpu_remove_autoreset(0);
	break;
	case CLOCK_EVT_MODE_UNUSED:
	case CLOCK_EVT_MODE_SHUTDOWN:
	break;
	}
	}

	static struct clock_event_device clockevent_mpu_timer1 = {
	.name = "mpu_timer1",
	.features = CLOCK_EVT_FEAT_PERIODIC, CLOCK_EVT_FEAT_ONESHOT,
	.shift = 32,
	.set_next_event = omap_mpu_set_next_event,
	.set_mode = omap_mpu_set_mode,
	};

	static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id)
	{
	struct clock_event_device *evt = &clockevent_mpu_timer1;

	evt->event_handler(evt);

	return IRQ_HANDLED;
	}

	static struct irqaction omap_mpu_timer1_irq = {
	.name = "mpu_timer1",
	.flags = IRQF_DISABLED \| IRQF_TIMER,
	.handler = omap_mpu_timer1_interrupt,
	};

	static __init void omap_init_mpu_timer(unsigned long rate)
	{
	set_cyc2ns_scale(rate / 1000);

	setup_irq(INT_TIMER1, &omap_mpu_timer1_irq);
	omap_mpu_timer_start(0, (rate / HZ) - 1, 1);

	clockevent_mpu_timer1.mult = div_sc(rate, NSEC_PER_SEC,
	clockevent_mpu_timer1.shift);
	clockevent_mpu_timer1.max_delta_ns =
	clockevent_delta2ns(-1, &clockevent_mpu_timer1);
	clockevent_mpu_timer1.min_delta_ns =
	clockevent_delta2ns(1, &clockevent_mpu_timer1);

	clockevent_mpu_timer1.cpumask = cpumask_of_cpu(0);
	clockevents_register_device(&clockevent_mpu_timer1);
	}


	/*
	* ---------------------------------------------------------------------------
	* MPU timer 2 ... free running 32-bit clock source and scheduler clock
	* ---------------------------------------------------------------------------
	*/

	static unsigned long omap_mpu_timer2_overflows;

	static irqreturn_t omap_mpu_timer2_interrupt(int irq, void *dev_id)
	{
	omap_mpu_timer2_overflows++;
	return IRQ_HANDLED;
	}

	static struct irqaction omap_mpu_timer2_irq = {
	.name = "mpu_timer2",
	.flags = IRQF_DISABLED,
	.handler = omap_mpu_timer2_interrupt,
	};

	static cycle_t mpu_read(void)
	{
	return ~omap_mpu_timer_read(1);
	}

	static struct clocksource clocksource_mpu = {
	.name = "mpu_timer2",
	.rating = 300,
	.read = mpu_read,
	.mask = CLOCKSOURCE_MASK(32),
	.shift = 24,
	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
	};

	static void __init omap_init_clocksource(unsigned long rate)
	{
	static char err[] __initdata = KERN_ERR
	"%s: can't register clocksource!\n";

	clocksource_mpu.mult
	= clocksource_khz2mult(rate/1000, clocksource_mpu.shift);

	setup_irq(INT_TIMER2, &omap_mpu_timer2_irq);
	omap_mpu_timer_start(1, ~0, 1);

	if (clocksource_register(&clocksource_mpu))
	printk(err, clocksource_mpu.name);
	}


	/*
	* Scheduler clock - returns current time in nanosec units.
	*/
	unsigned long long sched_clock(void)
	{
	unsigned long ticks = 0 - omap_mpu_timer_read(1);
	unsigned long long ticks64;

	ticks64 = omap_mpu_timer2_overflows;
	ticks64 <<= 32;
	ticks64 \|= ticks;

	return cycles_2_ns(ticks64);
	}

	/*
	* ---------------------------------------------------------------------------
	* Timer initialization
	* ---------------------------------------------------------------------------
	*/
	static void __init omap_timer_init(void)
	{
	struct clk *ck_ref = clk_get(NULL, "ck_ref");
	unsigned long rate;

	BUG_ON(IS_ERR(ck_ref));

	rate = clk_get_rate(ck_ref);
	clk_put(ck_ref);

	/* PTV = 0 */
	rate /= 2;

	omap_init_mpu_timer(rate);
	omap_init_clocksource(rate);
	}

	struct sys_timer omap_timer = {
	.init = omap_timer_init,
	};