|  | /* | 
|  | * 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: | 
|  | case CLOCK_EVT_MODE_RESUME: | 
|  | 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 | IRQF_IRQPOLL, | 
|  | .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, | 
|  | }; |