/*
- * arch/arm/mach-omap/time.c
+ * linux/arch/arm/mach-omap/time.c
*
- * OMAP Timer Tick
+ * 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>
*
#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/irq.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
-#include <asm/arch/clocks.h>
-
-#ifndef __instrument
-#define __instrument
-#define __noinstrument __attribute__ ((no_instrument_function))
-#endif
-typedef struct {
- u32 cntl; /* CNTL_TIMER, R/W */
- u32 load_tim; /* LOAD_TIM, W */
- u32 read_tim; /* READ_TIM, R */
-} mputimer_regs_t;
-
-#define mputimer_base(n) \
- ((volatile mputimer_regs_t*)IO_ADDRESS(OMAP_MPUTIMER_BASE + \
- (n)*OMAP_MPUTIMER_OFFSET))
-
-static inline unsigned long timer32k_read(int reg) {
- unsigned long val;
- val = omap_readw(reg + OMAP_32kHz_TIMER_BASE);
- return val;
-}
-static inline void timer32k_write(int reg,int val) {
- omap_writew(val, reg + OMAP_32kHz_TIMER_BASE);
-}
+struct sys_timer omap_timer;
/*
- * How long is the timer interval? 100 HZ, right...
- * IRQ rate = (TVR + 1) / 32768 seconds
- * TVR = 32768 * IRQ_RATE -1
- * IRQ_RATE = 1/100
- * TVR = 326
+ * ---------------------------------------------------------------------------
+ * MPU timer
+ * ---------------------------------------------------------------------------
*/
-#define TIMER32k_PERIOD 326
-//#define TIMER32k_PERIOD 0x7ff
+#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
-static inline void start_timer32k(void) {
- timer32k_write(TIMER32k_CR,
- TIMER32k_TSS | TIMER32k_TRB |
- TIMER32k_INT | TIMER32k_ARL);
-}
+#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)
-#ifdef CONFIG_MACH_OMAP_PERSEUS2
/*
- * After programming PTV with 0 and setting the MPUTIM_CLOCK_ENABLE
- * (external clock enable) bit, the timer count rate is 6.5 MHz (13
- * MHZ input/2). !! The divider by 2 is undocumented !!
+ * 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.
*/
-#define MPUTICKS_PER_SEC (13000000/2)
-#else
-/*
- * After programming PTV with 0, the timer count rate is 6 MHz.
- * WARNING! this must be an even number, or machinecycles_to_usecs
- * below will break.
+#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 MPUTICKS_PER_SEC (12000000/2)
+#define MPU_TICKS_PER_SEC (13000000 / 2)
+#else
+#define MPU_TICKS_PER_SEC (12000000 / 2)
#endif
-static int mputimer_started[3] = {0,0,0};
+#define MPU_TIMER_TICK_PERIOD ((MPU_TICKS_PER_SEC / HZ) - 1)
-static inline void __noinstrument start_mputimer(int n,
- unsigned long load_val)
-{
- volatile mputimer_regs_t* timer = mputimer_base(n);
-
- mputimer_started[n] = 0;
- timer->cntl = MPUTIM_CLOCK_ENABLE;
- udelay(1);
-
- timer->load_tim = load_val;
- udelay(1);
- timer->cntl = (MPUTIM_CLOCK_ENABLE | MPUTIM_AR | MPUTIM_ST);
- mputimer_started[n] = 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;
-static inline unsigned long __noinstrument
-read_mputimer(int n)
-{
- volatile mputimer_regs_t* timer = mputimer_base(n);
- return (mputimer_started[n] ? timer->read_tim : 0);
-}
+#define omap_mpu_timer_base(n) \
+((volatile omap_mpu_timer_regs_t*)IO_ADDRESS(OMAP_MPU_TIMER_BASE + \
+ (n)*OMAP_MPU_TIMER_OFFSET))
-void __noinstrument start_mputimer1(unsigned long load_val)
-{
- start_mputimer(0, load_val);
-}
-void __noinstrument start_mputimer2(unsigned long load_val)
+static inline unsigned long omap_mpu_timer_read(int nr)
{
- start_mputimer(1, load_val);
-}
-void __noinstrument start_mputimer3(unsigned long load_val)
-{
- start_mputimer(2, load_val);
+ volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
+ return timer->read_tim;
}
-unsigned long __noinstrument read_mputimer1(void)
-{
- return read_mputimer(0);
-}
-unsigned long __noinstrument read_mputimer2(void)
-{
- return read_mputimer(1);
-}
-unsigned long __noinstrument read_mputimer3(void)
+static inline void omap_mpu_timer_start(int nr, unsigned long load_val)
{
- return read_mputimer(2);
-}
+ volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
-unsigned long __noinstrument do_getmachinecycles(void)
-{
- return 0 - read_mputimer(0);
+ 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 __noinstrument machinecycles_to_usecs(unsigned long mputicks)
+unsigned long omap_mpu_timer_ticks_to_usecs(unsigned long nr_ticks)
{
/* Round up to nearest usec */
- return ((mputicks * 1000) / (MPUTICKS_PER_SEC / 2 / 1000) + 1) >> 1;
+ return ((nr_ticks * 1000) / (MPU_TICKS_PER_SEC / 2 / 1000) + 1) >> 1;
}
/*
- * This marks the time of the last system timer interrupt
- * that was *processed by the ISR* (timer 2).
+ * Last processed system timer interrupt
*/
-static unsigned long systimer_mark;
+static unsigned long omap_mpu_timer_last = 0;
-static unsigned long omap_gettimeoffset(void)
+/*
+ * Returns elapsed usecs since last system timer interrupt
+ */
+static unsigned long omap_mpu_timer_gettimeoffset(void)
{
- /* Return elapsed usecs since last system timer ISR */
- return machinecycles_to_usecs(do_getmachinecycles() - systimer_mark);
+ 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);
}
-static irqreturn_t
-omap_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+/*
+ * 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, ilatency;
-
- /*
- * Mark the time at which the timer interrupt ocurred using
- * timer1. We need to remove interrupt latency, which we can
- * retrieve from the current system timer2 counter. Both the
- * offset timer1 and the system timer2 are counting at 6MHz,
- * so we're ok.
- */
- now = 0 - read_mputimer1();
- ilatency = MPUTICKS_PER_SEC / 100 - read_mputimer2();
- systimer_mark = now - ilatency;
+ 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_timer_irq = {
- .name = "OMAP Timer Tick",
+static struct irqaction omap_mpu_timer_irq = {
+ .name = "mpu timer",
.flags = SA_INTERRUPT,
- .handler = omap_timer_interrupt
+ .handler = omap_mpu_timer_interrupt
};
-void __init omap_init_time(void)
+static __init void omap_init_mpu_timer(void)
{
- /* Since we don't call request_irq, we must init the structure */
- gettimeoffset = omap_gettimeoffset;
-
-#ifdef OMAP1510_USE_32KHZ_TIMER
- timer32k_write(TIMER32k_CR, 0x0);
- timer32k_write(TIMER32k_TVR,TIMER32k_PERIOD);
- setup_irq(INT_OS_32kHz_TIMER, &omap_timer_irq);
- start_timer32k();
-#else
- setup_irq(INT_TIMER2, &omap_timer_irq);
- start_mputimer2(MPUTICKS_PER_SEC / 100 - 1);
-#endif
+ omap_timer.offset = omap_mpu_timer_gettimeoffset;
+ setup_irq(INT_TIMER2, &omap_mpu_timer_irq);
+ omap_mpu_timer_start(0, 0xffffffff);
+ omap_mpu_timer_start(1, MPU_TIMER_TICK_PERIOD);
}
+/*
+ * ---------------------------------------------------------------------------
+ * Timer initialization
+ * ---------------------------------------------------------------------------
+ */
+void __init omap_timer_init(void)
+{
+ omap_init_mpu_timer();
+}
+
+struct sys_timer omap_timer = {
+ .init = omap_timer_init,
+ .offset = NULL, /* Initialized later */
+};
git://git.onelab.eu / linux-2.6.git / blobdiff