| /* MN10300 Low level time management |
| * |
| * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| * - Derived from arch/i386/kernel/time.c |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public Licence |
| * as published by the Free Software Foundation; either version |
| * 2 of the Licence, or (at your option) any later version. |
| */ |
| #include <linux/sched.h> |
| #include <linux/kernel.h> |
| #include <linux/interrupt.h> |
| #include <linux/time.h> |
| #include <linux/init.h> |
| #include <linux/smp.h> |
| #include <linux/profile.h> |
| #include <asm/irq.h> |
| #include <asm/div64.h> |
| #include <asm/processor.h> |
| #include <asm/intctl-regs.h> |
| #include <asm/rtc.h> |
| |
| #ifdef CONFIG_MN10300_RTC |
| unsigned long mn10300_ioclk; /* system I/O clock frequency */ |
| unsigned long mn10300_iobclk; /* system I/O clock frequency */ |
| unsigned long mn10300_tsc_per_HZ; /* number of ioclks per jiffy */ |
| #endif /* CONFIG_MN10300_RTC */ |
| |
| static unsigned long mn10300_last_tsc; /* time-stamp counter at last time |
| * interrupt occurred */ |
| |
| static irqreturn_t timer_interrupt(int irq, void *dev_id); |
| |
| static struct irqaction timer_irq = { |
| .handler = timer_interrupt, |
| .flags = IRQF_DISABLED | IRQF_SHARED | IRQF_TIMER, |
| .mask = CPU_MASK_NONE, |
| .name = "timer", |
| }; |
| |
| /* |
| * scheduler clock - returns current time in nanosec units. |
| */ |
| unsigned long long sched_clock(void) |
| { |
| union { |
| unsigned long long l; |
| u32 w[2]; |
| } quot; |
| |
| quot.w[0] = mn10300_last_tsc - get_cycles(); |
| quot.w[1] = 1000000000; |
| |
| asm("mulu %2,%3,%0,%1" |
| : "=r"(quot.w[1]), "=r"(quot.w[0]) |
| : "0"(quot.w[1]), "1"(quot.w[0]) |
| : "cc"); |
| |
| do_div(quot.l, MN10300_TSCCLK); |
| |
| return quot.l; |
| } |
| |
| /* |
| * advance the kernel's time keeping clocks (xtime and jiffies) |
| * - we use Timer 0 & 1 cascaded as a clock to nudge us the next time |
| * there's a need to update |
| */ |
| static irqreturn_t timer_interrupt(int irq, void *dev_id) |
| { |
| unsigned tsc, elapse; |
| |
| write_seqlock(&xtime_lock); |
| |
| while (tsc = get_cycles(), |
| elapse = mn10300_last_tsc - tsc, /* time elapsed since last |
| * tick */ |
| elapse > MN10300_TSC_PER_HZ |
| ) { |
| mn10300_last_tsc -= MN10300_TSC_PER_HZ; |
| |
| /* advance the kernel's time tracking system */ |
| profile_tick(CPU_PROFILING); |
| do_timer(1); |
| check_rtc_time(); |
| } |
| |
| write_sequnlock(&xtime_lock); |
| |
| update_process_times(user_mode(get_irq_regs())); |
| |
| return IRQ_HANDLED; |
| } |
| |
| /* |
| * initialise the various timers used by the main part of the kernel |
| */ |
| void __init time_init(void) |
| { |
| /* we need the prescalar running to be able to use IOCLK/8 |
| * - IOCLK runs at 1/4 (ST5 open) or 1/8 (ST5 closed) internal CPU clock |
| * - IOCLK runs at Fosc rate (crystal speed) |
| */ |
| TMPSCNT |= TMPSCNT_ENABLE; |
| |
| startup_timestamp_counter(); |
| |
| printk(KERN_INFO |
| "timestamp counter I/O clock running at %lu.%02lu" |
| " (calibrated against RTC)\n", |
| MN10300_TSCCLK / 1000000, (MN10300_TSCCLK / 10000) % 100); |
| |
| xtime.tv_sec = get_initial_rtc_time(); |
| xtime.tv_nsec = 0; |
| |
| mn10300_last_tsc = TMTSCBC; |
| |
| /* use timer 0 & 1 cascaded to tick at as close to HZ as possible */ |
| setup_irq(TMJCIRQ, &timer_irq); |
| |
| set_intr_level(TMJCIRQ, TMJCICR_LEVEL); |
| |
| startup_jiffies_counter(); |
| |
| #ifdef CONFIG_MN10300_WD_TIMER |
| /* start the watchdog timer */ |
| watchdog_go(); |
| #endif |
| } |