/* * arch/arm/plat-iop/time.c * * Timer code for IOP32x and IOP33x based systems * * Author: Deepak Saxena <dsaxena@mvista.com> * * Copyright 2002-2003 MontaVista Software Inc. * * 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. */ #include <linux/kernel.h> #include <linux/interrupt.h> #include <linux/time.h> #include <linux/init.h> #include <linux/timex.h> #include <linux/io.h> #include <mach/hardware.h> #include <asm/irq.h> #include <asm/uaccess.h> #include <asm/mach/irq.h> #include <asm/mach/time.h> #include <mach/time.h> static unsigned long ticks_per_jiffy; static unsigned long ticks_per_usec; static unsigned long next_jiffy_time; unsigned long iop_gettimeoffset(void) { unsigned long offset, temp; /* enable cp6, if necessary, to avoid taking the overhead of an * undefined instruction trap */ asm volatile ( "mrc p15, 0, %0, c15, c1, 0\n\t" "tst %0, #(1 << 6)\n\t" "orreq %0, %0, #(1 << 6)\n\t" "mcreq p15, 0, %0, c15, c1, 0\n\t" #ifdef CONFIG_CPU_XSCALE "mrceq p15, 0, %0, c15, c1, 0\n\t" "moveq %0, %0\n\t" "subeq pc, pc, #4\n\t" #endif : "=r"(temp) : : "cc"); offset = next_jiffy_time - read_tcr1(); return offset / ticks_per_usec; } static irqreturn_t iop_timer_interrupt(int irq, void *dev_id) { write_tisr(1); while ((signed long)(next_jiffy_time - read_tcr1()) >= ticks_per_jiffy) { timer_tick(); next_jiffy_time -= ticks_per_jiffy; } return IRQ_HANDLED; } static struct irqaction iop_timer_irq = { .name = "IOP Timer Tick", .handler = iop_timer_interrupt, .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, }; static unsigned long iop_tick_rate; unsigned long get_iop_tick_rate(void) { return iop_tick_rate; } EXPORT_SYMBOL(get_iop_tick_rate); void __init iop_init_time(unsigned long tick_rate) { u32 timer_ctl; ticks_per_jiffy = (tick_rate + HZ/2) / HZ; ticks_per_usec = tick_rate / 1000000; next_jiffy_time = 0xffffffff; iop_tick_rate = tick_rate; timer_ctl = IOP_TMR_EN | IOP_TMR_PRIVILEGED | IOP_TMR_RELOAD | IOP_TMR_RATIO_1_1; /* * We use timer 0 for our timer interrupt, and timer 1 as * monotonic counter for tracking missed jiffies. */ write_trr0(ticks_per_jiffy - 1); write_tmr0(timer_ctl); write_trr1(0xffffffff); write_tmr1(timer_ctl); setup_irq(IRQ_IOP_TIMER0, &iop_timer_irq); }