2 * arch/arm/mach-iop3xx/iop321-time.c
4 * Timer code for IOP321 based systems
6 * Author: Deepak Saxena <dsaxena@mvista.com>
8 * Copyright 2002-2003 MontaVista Software Inc.
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the
12 * Free Software Foundation; either version 2 of the License, or (at your
13 * option) any later version.
16 #include <linux/kernel.h>
17 #include <linux/interrupt.h>
18 #include <linux/time.h>
19 #include <linux/init.h>
20 #include <linux/timex.h>
22 #include <asm/hardware.h>
25 #include <asm/uaccess.h>
26 #include <asm/mach/irq.h>
27 #include <asm/mach/time.h>
29 #define IOP321_TIME_SYNC 0
31 static inline unsigned long get_elapsed(void)
33 return LATCH - *IOP321_TU_TCR0;
36 static unsigned long iop321_gettimeoffset(void)
38 unsigned long elapsed, usec;
42 * If an interrupt was pending before we read the timer,
43 * we've already wrapped. Factor this into the time.
44 * If an interrupt was pending after we read the timer,
45 * it may have wrapped between checking the interrupt
46 * status and reading the timer. Re-read the timer to
47 * be sure its value is after the wrap.
50 asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr1));
51 elapsed = get_elapsed();
52 asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr2));
57 elapsed = LATCH + get_elapsed();
60 * Now convert them to usec.
62 usec = (unsigned long)(elapsed / (CLOCK_TICK_RATE/1000000));
68 iop321_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
72 write_seqlock(&xtime_lock);
74 asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr));
76 asm volatile("mcr p6, 0, %0, c6, c1, 0" : : "r" (tisr));
80 write_sequnlock(&xtime_lock);
85 static struct irqaction iop321_timer_irq = {
86 .name = "IOP321 Timer Tick",
87 .handler = iop321_timer_interrupt,
88 .flags = SA_INTERRUPT | SA_TIMER,
91 static void __init iop321_timer_init(void)
95 setup_irq(IRQ_IOP321_TIMER0, &iop321_timer_irq);
97 timer_ctl = IOP321_TMR_EN | IOP321_TMR_PRIVILEGED | IOP321_TMR_RELOAD |
100 asm volatile("mcr p6, 0, %0, c4, c1, 0" : : "r" (LATCH));
102 asm volatile("mcr p6, 0, %0, c0, c1, 0" : : "r" (timer_ctl));
105 struct sys_timer iop321_timer = {
106 .init = &iop321_timer_init,
107 .offset = iop321_gettimeoffset,