time.h

来自「基于组件方式开发操作系统的OSKIT源代码」· C头文件 代码 · 共 70 行

/*
 * linux/include/asm-arm/arch-nexuspci/time.h
 *
 * Copyright (c) 1997 Phil Blundell.
 *
 * Nexus PCI card has no real-time clock.  We get timer ticks from the
 * SCC chip.
 */

#define UART_BASE		0xfff00000
#define INTCONT			0xffe00000

#define update_rtc()

extern __inline__ unsigned long gettimeoffset (void)
{
	return 0;
}

static void timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	static int count = 50;

	writeb(0x90, UART_BASE + 8);

	if (--count == 0) {
		static int state = 1;
		state ^= 1;
		writeb(0x1a + state, INTCONT);
		count = 50;
	}

	readb(UART_BASE + 0x14);
	readb(UART_BASE + 0x14);
	readb(UART_BASE + 0x14);
	readb(UART_BASE + 0x14);
	readb(UART_BASE + 0x14);
	readb(UART_BASE + 0x14);

	do_timer(regs);	
}

static struct irqaction timerirq = {
	timer_interrupt,
	0,
	0,
	"timer",
	NULL,
	NULL
};

extern __inline__ void setup_timer(void)
{
	int tick = 3686400 / 16 / 2 / 100;

	writeb(tick & 0xff, UART_BASE + 0x1c);
	writeb(tick >> 8, UART_BASE + 0x18);
	writeb(0x80, UART_BASE + 8);
	writeb(0x10, UART_BASE + 0x14);

	/*
	 * Default the date to 1 Jan 1970 0:0:0
	 * You will have to run a time daemon to set the
	 * clock correctly at bootup
	 */
	xtime.tv_sec = mktime(1970, 1, 1, 0, 0, 0);

	setup_arm_irq(IRQ_TIMER, &timerirq);
}