1/* time.c: FRV arch-specific time handling 2 * 3 * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells (dhowells@redhat.com) 5 * - Derived from arch/m68k/kernel/time.c 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 */ 12 13#include <linux/module.h> 14#include <linux/errno.h> 15#include <linux/sched.h> 16#include <linux/kernel.h> 17#include <linux/param.h> 18#include <linux/string.h> 19#include <linux/interrupt.h> 20#include <linux/profile.h> 21#include <linux/irq.h> 22#include <linux/mm.h> 23 24#include <asm/io.h> 25#include <asm/timer-regs.h> 26#include <asm/mb-regs.h> 27#include <asm/mb86943a.h> 28 29#include <linux/timex.h> 30 31#define TICK_SIZE (tick_nsec / 1000) 32 33unsigned long __nongprelbss __clkin_clock_speed_HZ; 34unsigned long __nongprelbss __ext_bus_clock_speed_HZ; 35unsigned long __nongprelbss __res_bus_clock_speed_HZ; 36unsigned long __nongprelbss __sdram_clock_speed_HZ; 37unsigned long __nongprelbss __core_bus_clock_speed_HZ; 38unsigned long __nongprelbss __core_clock_speed_HZ; 39unsigned long __nongprelbss __dsu_clock_speed_HZ; 40unsigned long __nongprelbss __serial_clock_speed_HZ; 41unsigned long __delay_loops_MHz; 42 43static irqreturn_t timer_interrupt(int irq, void *dummy); 44 45static struct irqaction timer_irq = { 46 .handler = timer_interrupt, 47 .flags = IRQF_DISABLED, 48 .name = "timer", 49}; 50 51/* 52 * timer_interrupt() needs to keep up the real-time clock, 53 * as well as call the "do_timer()" routine every clocktick 54 */ 55static irqreturn_t timer_interrupt(int irq, void *dummy) 56{ 57 profile_tick(CPU_PROFILING); 58 /* 59 * Here we are in the timer irq handler. We just have irqs locally 60 * disabled but we don't know if the timer_bh is running on the other 61 * CPU. We need to avoid to SMP race with it. NOTE: we don't need 62 * the irq version of write_lock because as just said we have irq 63 * locally disabled. -arca 64 */ 65 write_seqlock(&xtime_lock); 66 67 do_timer(1); 68 69#ifdef CONFIG_HEARTBEAT 70 static unsigned short n; 71 n++; 72 __set_LEDS(n); 73#endif /* CONFIG_HEARTBEAT */ 74 75 write_sequnlock(&xtime_lock); 76 77 update_process_times(user_mode(get_irq_regs())); 78 79 return IRQ_HANDLED; 80} 81 82void time_divisor_init(void) 83{ 84 unsigned short base, pre, prediv; 85 86 /* set the scheduling timer going */ 87 pre = 1; 88 prediv = 4; 89 base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv); 90 91 __set_TPRV(pre); 92 __set_TxCKSL_DATA(0, prediv); 93 __set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2); 94 __set_TCSR_DATA(0, base & 0xff); 95 __set_TCSR_DATA(0, base >> 8); 96} 97 98 99void read_persistent_clock(struct timespec *ts) 100{ 101 unsigned int year, mon, day, hour, min, sec; 102 103 extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec); 104 105 /* FIX by dqg : Set to zero for platforms that don't have tod */ 106 /* without this time is undefined and can overflow time_t, causing */ 107 /* very strange errors */ 108 year = 1980; 109 mon = day = 1; 110 hour = min = sec = 0; 111 arch_gettod (&year, &mon, &day, &hour, &min, &sec); 112 113 if ((year += 1900) < 1970) 114 year += 100; 115 ts->tv_sec = mktime(year, mon, day, hour, min, sec); 116 ts->tv_nsec = 0; 117} 118 119void time_init(void) 120{ 121 /* install scheduling interrupt handler */ 122 setup_irq(IRQ_CPU_TIMER0, &timer_irq); 123 124 time_divisor_init(); 125} 126 127/* 128 * Scheduler clock - returns current time in nanosec units. 129 */ 130unsigned long long sched_clock(void) 131{ 132 return jiffies_64 * (1000000000 / HZ); 133} 134