time.c

来自「最新版的u-boot,2008-10-18发布」· C语言 代码 · 共 112 行

/*
 * Copyright (C) 2007,2008 Nobobuhiro Iwamatsu <[e-mail]>
 * Copyright (C) 2008 Renesas Solutions Corp.
 *
 * (C) Copyright 2003
 * Wolfgang Denk, DENX Software Engineering, [e-mail].
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <common.h>
#include <asm/io.h>
#include <asm/processor.h>

#define CMT_CMCSR_INIT  0x0001	/* PCLK/32 */
#define CMT_CMCSR_CALIB 0x0000
#define CMT_MAX_COUNTER (0xFFFFFFFF)
#define CMT_TIMER_RESET (0xFFFF)

static vu_long cmt0_timer;

static void cmt_timer_start(unsigned int timer)
{
	writew(readw(CMSTR) | 0x01, CMSTR);
}

static void cmt_timer_stop(unsigned int timer)
{
	writew(readw(CMSTR) & ~0x01, CMSTR);
}

int timer_init(void)
{
	cmt0_timer = 0;
	/* Divide clock by 32 */
	readw(CMCSR_0);
	writew(CMT_CMCSR_INIT, CMCSR_0);

	/* User Device 0 only */
	cmt_timer_stop(0);
	set_timer(CMT_TIMER_RESET);
	cmt_timer_start(0);

	return 0;
}

unsigned long long get_ticks(void)
{
	return cmt0_timer;
}

static vu_long cmcnt;
ulong get_timer(ulong base)
{
	ulong data = readw(CMCNT_0);

	if (data >= cmcnt)
		cmcnt = data - cmcnt;
	else
		cmcnt = (CMT_TIMER_RESET - cmcnt) + data;

	if ((cmt0_timer + cmcnt) > CMT_MAX_COUNTER)
		cmt0_timer = ((cmt0_timer + cmcnt) - CMT_MAX_COUNTER);
	else
		cmt0_timer += cmcnt;

	cmcnt = data;
	return cmt0_timer - base;
}

void set_timer(ulong t)
{
	writew((u16) t, CMCOR_0);
}

void reset_timer(void)
{
	cmt_timer_stop(0);
	set_timer(CMT_TIMER_RESET);
	cmt0_timer = 0;
	cmt_timer_start(0);
}

void udelay(unsigned long usec)
{
	unsigned int start = get_timer(0);

	while (get_timer((ulong) start) < (usec * (CFG_HZ / 1000000)))
		continue;
}

unsigned long get_tbclk(void)
{
	return CFG_HZ;
}