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Alessandro Rubinid5254f12009-01-24 18:10:37 +01001/*
Alessandro Rubini095a4602009-06-29 10:52:37 +02002 * (C) Copyright 2009 Alessandro Rubini
Alessandro Rubinid5254f12009-01-24 18:10:37 +01003 *
4 * See file CREDITS for list of people who contributed to this
5 * project.
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 as
9 * published by the Free Software Foundation; either version 2 of
10 * the License, or (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
20 * MA 02111-1307 USA
21 */
22
23#include <common.h>
24#include <asm/io.h>
Alessandro Rubini095a4602009-06-29 10:52:37 +020025#include <asm/arch/mtu.h>
Alessandro Rubinid5254f12009-01-24 18:10:37 +010026
Alessandro Rubini095a4602009-06-29 10:52:37 +020027/*
28 * The timer is a decrementer, we'll left it free running at 2.4MHz.
29 * We have 2.4 ticks per microsecond and an overflow in almost 30min
30 */
31#define TIMER_CLOCK (24 * 100 * 1000)
32#define COUNT_TO_USEC(x) ((x) * 5 / 12) /* overflows at 6min */
33#define USEC_TO_COUNT(x) ((x) * 12 / 5) /* overflows at 6min */
34#define TICKS_PER_HZ (TIMER_CLOCK / CONFIG_SYS_HZ)
35#define TICKS_TO_HZ(x) ((x) / TICKS_PER_HZ)
Alessandro Rubinid5254f12009-01-24 18:10:37 +010036
Alessandro Rubini095a4602009-06-29 10:52:37 +020037/* macro to read the 32 bit timer: since it decrements, we invert read value */
38#define READ_TIMER() (~readl(CONFIG_SYS_TIMERBASE + MTU_VAL(0)))
Alessandro Rubinid5254f12009-01-24 18:10:37 +010039
Alessandro Rubini095a4602009-06-29 10:52:37 +020040/* Configure a free-running, auto-wrap counter with no prescaler */
Alessandro Rubinid5254f12009-01-24 18:10:37 +010041int timer_init(void)
42{
Alessandro Rubini095a4602009-06-29 10:52:37 +020043 writel(MTU_CRn_ENA | MTU_CRn_PRESCALE_1 | MTU_CRn_32BITS,
44 CONFIG_SYS_TIMERBASE + MTU_CR(0));
45 reset_timer();
Alessandro Rubinid5254f12009-01-24 18:10:37 +010046 return 0;
47}
48
Alessandro Rubini095a4602009-06-29 10:52:37 +020049/* Restart counting from 0 */
Alessandro Rubinid5254f12009-01-24 18:10:37 +010050void reset_timer(void)
51{
Alessandro Rubini095a4602009-06-29 10:52:37 +020052 writel(0, CONFIG_SYS_TIMERBASE + MTU_LR(0)); /* Immediate effect */
Alessandro Rubinid5254f12009-01-24 18:10:37 +010053}
54
Alessandro Rubini095a4602009-06-29 10:52:37 +020055/* Return how many HZ passed since "base" */
Alessandro Rubinid5254f12009-01-24 18:10:37 +010056ulong get_timer(ulong base)
57{
Alessandro Rubini095a4602009-06-29 10:52:37 +020058 return TICKS_TO_HZ(READ_TIMER()) - base;
Alessandro Rubinid5254f12009-01-24 18:10:37 +010059}
60
Alessandro Rubini095a4602009-06-29 10:52:37 +020061/* Delay x useconds */
Alessandro Rubinid5254f12009-01-24 18:10:37 +010062void udelay(unsigned long usec)
63{
Alessandro Rubini095a4602009-06-29 10:52:37 +020064 ulong ini, end;
Alessandro Rubinid5254f12009-01-24 18:10:37 +010065
Alessandro Rubini095a4602009-06-29 10:52:37 +020066 ini = READ_TIMER();
67 end = ini + USEC_TO_COUNT(usec);
68 while ((signed)(end - READ_TIMER()) > 0)
69 ;
Alessandro Rubinid5254f12009-01-24 18:10:37 +010070}