2 * arch/arm/plat-iop/time.c
4 * Timer code for IOP32x and IOP33x 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>
21 #include <asm/hardware.h>
24 #include <asm/uaccess.h>
25 #include <asm/mach/irq.h>
26 #include <asm/mach/time.h>
28 #ifdef CONFIG_ARCH_IOP32X
29 #define IRQ_IOP3XX_TIMER0 IRQ_IOP32X_TIMER0
31 #ifdef CONFIG_ARCH_IOP33X
32 #define IRQ_IOP3XX_TIMER0 IRQ_IOP33X_TIMER0
36 static unsigned long ticks_per_jiffy;
37 static unsigned long ticks_per_usec;
38 static unsigned long next_jiffy_time;
40 unsigned long iop3xx_gettimeoffset(void)
44 offset = next_jiffy_time - *IOP3XX_TU_TCR1;
46 return offset / ticks_per_usec;
50 iop3xx_timer_interrupt(int irq, void *dev_id)
52 write_seqlock(&xtime_lock);
55 asm volatile("mcr p6, 0, %0, c6, c1, 0" : : "r" (1));
58 while ((signed long)(next_jiffy_time - *IOP3XX_TU_TCR1)
61 next_jiffy_time -= ticks_per_jiffy;
64 write_sequnlock(&xtime_lock);
69 static struct irqaction iop3xx_timer_irq = {
70 .name = "IOP3XX Timer Tick",
71 .handler = iop3xx_timer_interrupt,
72 .flags = IRQF_DISABLED | IRQF_TIMER,
75 void __init iop3xx_init_time(unsigned long tick_rate)
79 ticks_per_jiffy = (tick_rate + HZ/2) / HZ;
80 ticks_per_usec = tick_rate / 1000000;
81 next_jiffy_time = 0xffffffff;
83 timer_ctl = IOP3XX_TMR_EN | IOP3XX_TMR_PRIVILEGED |
84 IOP3XX_TMR_RELOAD | IOP3XX_TMR_RATIO_1_1;
87 * We use timer 0 for our timer interrupt, and timer 1 as
88 * monotonic counter for tracking missed jiffies.
91 asm volatile("mcr p6, 0, %0, c4, c1, 0" : : "r" (ticks_per_jiffy - 1));
92 asm volatile("mcr p6, 0, %0, c0, c1, 0" : : "r" (timer_ctl));
93 asm volatile("mcr p6, 0, %0, c5, c1, 0" : : "r" (0xffffffff));
94 asm volatile("mcr p6, 0, %0, c1, c1, 0" : : "r" (timer_ctl));
97 setup_irq(IRQ_IOP3XX_TIMER0, &iop3xx_timer_irq);