+++ /dev/null
-/*
- * linux/arch/arm/mach-omap/time.c
- *
- * OMAP Timers
- *
- * Copyright (C) 2004 Nokia Corporation
- * Partial timer rewrite and additional VST 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_TIMER1_BASE (0xfffec500)
-#define OMAP_MPU_TIMER2_BASE (0xfffec600)
-#define OMAP_MPU_TIMER3_BASE (0xfffec700)
-#define OMAP_MPU_TIMER_BASE OMAP_MPU_TIMER1_BASE
-#define OMAP_MPU_TIMER_OFFSET 0x100
-
-#define MPU_TIMER_FREE (1 << 6)
-#define MPU_TIMER_CLOCK_ENABLE (1 << 5)
-#define MPU_TIMER_AR (1 << 1)
-#define MPU_TIMER_ST (1 << 0)
-
-/* 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)
-
-/*
- * 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 MAX_SKIP_JIFFIES 25
-#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) {
- 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;
-}
-
-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)
-{
- 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
- * ---------------------------------------------------------------------------
- */
-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 */
-};
projects / linux-2.6-omap-h63xx.git / commitdiff