1. 根目录:
2. arch
3. h8300
4. kernel
5. timer
6. itu.c

/*
 *  linux/arch/h8300/kernel/timer/itu.c
 *
 *  Yoshinori Sato <ysato@users.sourcefoge.jp>
 *
 *  ITU Timer Handler
 *
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/timex.h>

#include <asm/segment.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/regs306x.h>

#if CONFIG_H8300_ITU_CH == 0
#define ITUBASE	0xffff64
#define ITUIRQ	24
#elif CONFIG_H8300_ITU_CH == 1
#define ITUBASE	0xffff6e
#define ITUIRQ	28
#elif CONFIG_H8300_ITU_CH == 2
#define ITUBASE	0xffff78
#define ITUIRQ	32
#elif CONFIG_H8300_ITU_CH == 3
#define ITUBASE	0xffff82
#define ITUIRQ	36
#elif CONFIG_H8300_ITU_CH == 4
#define ITUBASE	0xffff92
#define ITUIRQ	40
#else
#error Unknown timer channel.
#endif

#define TCR	0
#define TIOR	1
#define TIER	2
#define TSR	3
#define TCNT	4
#define GRA	6
#define GRB	8

static irqreturn_t timer_interrupt(int irq, void *dev_id)
{
	h8300_timer_tick();
	ctrl_bclr(IMFA, ITUBASE + TSR);
	return IRQ_HANDLED;
}

static struct irqaction itu_irq = {
	.name		= "itu",
	.handler	= timer_interrupt,
	.flags		= IRQF_DISABLED | IRQF_TIMER,
};

static const int __initdata divide_rate[] = {1, 2, 4, 8};

void __init h8300_timer_setup(void)
{
	unsigned int div;
	unsigned int cnt;

	calc_param(cnt, div, divide_rate, 0x10000);

	setup_irq(ITUIRQ, &itu_irq);

	/* initialize timer */
	ctrl_outb(0, TSTR);
	ctrl_outb(CCLR0 | div, ITUBASE + TCR);
	ctrl_outb(0x01, ITUBASE + TIER);
	ctrl_outw(cnt, ITUBASE + GRA);
	ctrl_bset(CONFIG_H8300_ITU_CH, TSTR);
}