/* * 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/config.h> #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 <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> struct sys_timer omap_timer; #ifdef CONFIG_OMAP_MPU_TIMER /* * --------------------------------------------------------------------------- * MPU timer * --------------------------------------------------------------------------- */ #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; } /* * MPU_TICKS_PER_SEC must be an even number, otherwise machinecycles_to_usecs * will break. On P2, the timer count rate is 6.5 MHz after programming PTV * with 0. This divides the 13MHz input by 2, and is undocumented. */ #ifdef CONFIG_MACH_OMAP_PERSEUS2 /* REVISIT: This ifdef construct should be replaced by a query to clock * framework to see if timer base frequency is 12.0, 13.0 or 19.2 MHz. */ #define MPU_TICKS_PER_SEC (13000000 / 2) #else #define MPU_TICKS_PER_SEC (12000000 / 2) #endif #define MPU_TIMER_TICK_PERIOD ((MPU_TICKS_PER_SEC / HZ) - 1) 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_timer_start(int nr, unsigned long load_val) { volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr); timer->cntl = MPU_TIMER_CLOCK_ENABLE; udelay(1); timer->load_tim = load_val; udelay(1); timer->cntl = (MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_AR | MPU_TIMER_ST); } unsigned long omap_mpu_timer_ticks_to_usecs(unsigned long nr_ticks) { unsigned long long nsec; nsec = cycles_2_ns((unsigned long long)nr_ticks); return (unsigned long)nsec / 1000; } /* * Last processed system timer interrupt */ static unsigned long omap_mpu_timer_last = 0; /* * Returns elapsed usecs since last system timer interrupt */ static unsigned long omap_mpu_timer_gettimeoffset(void) { unsigned long now = 0 - omap_mpu_timer_read(0); unsigned long elapsed = now - omap_mpu_timer_last; return omap_mpu_timer_ticks_to_usecs(elapsed); } /* * Elapsed time between interrupts is calculated using timer0. * Latency during the interrupt is calculated using timer1. * Both timer0 and timer1 are counting at 6MHz (P2 6.5MHz). */ static irqreturn_t omap_mpu_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) { unsigned long now, latency; write_seqlock(&xtime_lock); now = 0 - omap_mpu_timer_read(0); latency = MPU_TICKS_PER_SEC / HZ - omap_mpu_timer_read(1); omap_mpu_timer_last = now - latency; timer_tick(regs); write_sequnlock(&xtime_lock); return IRQ_HANDLED; } static struct irqaction omap_mpu_timer_irq = { .name = "mpu timer", .flags = SA_INTERRUPT | SA_TIMER, .handler = omap_mpu_timer_interrupt, }; static unsigned long omap_mpu_timer1_overflows; static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id, struct pt_regs *regs) { omap_mpu_timer1_overflows++; return IRQ_HANDLED; } static struct irqaction omap_mpu_timer1_irq = { .name = "mpu timer1 overflow", .flags = SA_INTERRUPT, .handler = omap_mpu_timer1_interrupt, }; static __init void omap_init_mpu_timer(void) { set_cyc2ns_scale(MPU_TICKS_PER_SEC / 1000); omap_timer.offset = omap_mpu_timer_gettimeoffset; setup_irq(INT_TIMER1, &omap_mpu_timer1_irq); setup_irq(INT_TIMER2, &omap_mpu_timer_irq); omap_mpu_timer_start(0, 0xffffffff); omap_mpu_timer_start(1, MPU_TIMER_TICK_PERIOD); } /* * Scheduler clock - returns current time in nanosec units. */ unsigned long long sched_clock(void) { unsigned long ticks = 0 - omap_mpu_timer_read(0); unsigned long long ticks64; ticks64 = omap_mpu_timer1_overflows; ticks64 <<= 32; ticks64 |= ticks; return cycles_2_ns(ticks64); } #endif /* CONFIG_OMAP_MPU_TIMER */ #ifdef CONFIG_OMAP_32K_TIMER #ifdef CONFIG_ARCH_OMAP1510 #error OMAP 32KHz timer does not currently work on 1510! #endif /* * --------------------------------------------------------------------------- * 32KHz OS timer * * This currently works only on 16xx, as 1510 does not have the continuous * 32KHz synchronous timer. The 32KHz synchronous timer is used to keep track * of time in addition to the 32KHz OS timer. Using only the 32KHz OS timer * on 1510 would be possible, but the timer would not be as accurate as * with the 32KHz synchronized timer. * --------------------------------------------------------------------------- */ #define OMAP_32K_TIMER_BASE 0xfffb9000 #define OMAP_32K_TIMER_CR 0x08 #define OMAP_32K_TIMER_TVR 0x00 #define OMAP_32K_TIMER_TCR 0x04 #define OMAP_32K_TICKS_PER_HZ (32768 / HZ) #if (32768 % HZ) != 0 /* We cannot ignore modulo. * Potential error can be as high as several percent. */ #define OMAP_32K_TICK_MODULO (32768 % HZ) static unsigned modulo_count = 0; /* Counts 1/HZ units */ #endif /* * TRM says 1 / HZ = ( TVR + 1) / 32768, so TRV = (32768 / HZ) - 1 * so with HZ = 100, TVR = 327.68. */ #define OMAP_32K_TIMER_TICK_PERIOD ((32768 / HZ) - 1) #define TIMER_32K_SYNCHRONIZED 0xfffbc410 #define JIFFIES_TO_HW_TICKS(nr_jiffies, clock_rate) \ (((nr_jiffies) * (clock_rate)) / HZ) static inline void omap_32k_timer_write(int val, int reg) { omap_writew(val, reg + OMAP_32K_TIMER_BASE); } static inline unsigned long omap_32k_timer_read(int reg) { return omap_readl(reg + OMAP_32K_TIMER_BASE) & 0xffffff; } /* * The 32KHz synchronized timer is an additional timer on 16xx. * It is always running. */ static inline unsigned long omap_32k_sync_timer_read(void) { return omap_readl(TIMER_32K_SYNCHRONIZED); } static inline void omap_32k_timer_start(unsigned long load_val) { omap_32k_timer_write(load_val, OMAP_32K_TIMER_TVR); omap_32k_timer_write(0x0f, OMAP_32K_TIMER_CR); } static inline void omap_32k_timer_stop(void) { omap_32k_timer_write(0x0, OMAP_32K_TIMER_CR); } /* * Rounds down to nearest usec */ static inline unsigned long omap_32k_ticks_to_usecs(unsigned long ticks_32k) { return (ticks_32k * 5*5*5*5*5*5) >> 9; } static unsigned long omap_32k_last_tick = 0; /* * Returns elapsed usecs since last 32k timer interrupt */ static unsigned long omap_32k_timer_gettimeoffset(void) { unsigned long now = omap_32k_sync_timer_read(); return omap_32k_ticks_to_usecs(now - omap_32k_last_tick); } /* * Timer interrupt for 32KHz timer. When dynamic tick is enabled, this * function is also called from other interrupts to remove latency * issues with dynamic tick. In the dynamic tick case, we need to lock * with irqsave. */ static irqreturn_t omap_32k_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) { unsigned long flags; unsigned long now; write_seqlock_irqsave(&xtime_lock, flags); now = omap_32k_sync_timer_read(); while (now - omap_32k_last_tick >= OMAP_32K_TICKS_PER_HZ) { #ifdef OMAP_32K_TICK_MODULO /* Modulo addition may put omap_32k_last_tick ahead of now * and cause unwanted repetition of the while loop. */ if (unlikely(now - omap_32k_last_tick == ~0)) break; modulo_count += OMAP_32K_TICK_MODULO; if (modulo_count > HZ) { ++omap_32k_last_tick; modulo_count -= HZ; } #endif omap_32k_last_tick += OMAP_32K_TICKS_PER_HZ; timer_tick(regs); } /* Restart timer so we don't drift off due to modulo or dynamic tick. * By default we program the next timer to be continuous to avoid * latencies during high system load. During dynamic tick operation the * continuous timer can be overridden from pm_idle to be longer. */ omap_32k_timer_start(omap_32k_last_tick + OMAP_32K_TICKS_PER_HZ - now); write_sequnlock_irqrestore(&xtime_lock, flags); return IRQ_HANDLED; } #ifdef CONFIG_NO_IDLE_HZ /* * Programs the next timer interrupt needed. Called when dynamic tick is * enabled, and to reprogram the ticks to skip from pm_idle. Note that * we can keep the timer continuous, and don't need to set it to run in * one-shot mode. This is because the timer will get reprogrammed again * after next interrupt. */ void omap_32k_timer_reprogram(unsigned long next_tick) { omap_32k_timer_start(JIFFIES_TO_HW_TICKS(next_tick, 32768) + 1); } static struct irqaction omap_32k_timer_irq; extern struct timer_update_handler timer_update; static int omap_32k_timer_enable_dyn_tick(void) { /* No need to reprogram timer, just use the next interrupt */ return 0; } static int omap_32k_timer_disable_dyn_tick(void) { omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD); return 0; } static struct dyn_tick_timer omap_dyn_tick_timer = { .enable = omap_32k_timer_enable_dyn_tick, .disable = omap_32k_timer_disable_dyn_tick, .reprogram = omap_32k_timer_reprogram, .handler = omap_32k_timer_interrupt, }; #endif /* CONFIG_NO_IDLE_HZ */ static struct irqaction omap_32k_timer_irq = { .name = "32KHz timer", .flags = SA_INTERRUPT | SA_TIMER, .handler = omap_32k_timer_interrupt, }; static __init void omap_init_32k_timer(void) { #ifdef CONFIG_NO_IDLE_HZ omap_timer.dyn_tick = &omap_dyn_tick_timer; #endif setup_irq(INT_OS_TIMER, &omap_32k_timer_irq); omap_timer.offset = omap_32k_timer_gettimeoffset; omap_32k_last_tick = omap_32k_sync_timer_read(); omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD); } #endif /* CONFIG_OMAP_32K_TIMER */ /* * --------------------------------------------------------------------------- * Timer initialization * --------------------------------------------------------------------------- */ static void __init omap_timer_init(void) { #if defined(CONFIG_OMAP_MPU_TIMER) omap_init_mpu_timer(); #elif defined(CONFIG_OMAP_32K_TIMER) omap_init_32k_timer(); #else #error No system timer selected in Kconfig! #endif } struct sys_timer omap_timer = { .init = omap_timer_init, .offset = NULL, /* Initialized later */ };