1 /*
2 * (C) Copyright 2003
3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
4 *
5 * See file CREDITS for list of people who contributed to this
6 * project.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21 * MA 02111-1307 USA
22 */
24 #include <common.h>
25 #include <asm/mipsregs.h>
27 static unsigned long timestamp;
29 /* how many counter cycles in a jiffy */
30 #define CYCLES_PER_JIFFY \
31 (CONFIG_SYS_MIPS_TIMER_FREQ + CONFIG_SYS_HZ / 2) / CONFIG_SYS_HZ
33 /*
34 * timer without interrupts
35 */
37 int timer_init(void)
38 {
39 /* Set up the timer for the first expiration. */
40 timestamp = 0;
41 write_c0_compare(read_c0_count() + CYCLES_PER_JIFFY);
43 return 0;
44 }
46 ulong get_timer(ulong base)
47 {
48 unsigned int count;
49 unsigned int expirelo = read_c0_compare();
51 /* Check to see if we have missed any timestamps. */
52 count = read_c0_count();
53 while ((count - expirelo) < 0x7fffffff) {
54 expirelo += CYCLES_PER_JIFFY;
55 timestamp++;
56 }
57 write_c0_compare(expirelo);
59 return timestamp - base;
60 }
62 void __udelay(unsigned long usec)
63 {
64 unsigned int tmo;
66 tmo = read_c0_count() + (usec * (CONFIG_SYS_MIPS_TIMER_FREQ / 1000000));
67 while ((tmo - read_c0_count()) < 0x7fffffff)
68 /*NOP*/;
69 }
71 /*
72 * This function is derived from PowerPC code (read timebase as long long).
73 * On MIPS it just returns the timer value.
74 */
75 unsigned long long get_ticks(void)
76 {
77 return get_timer(0);
78 }
80 /*
81 * This function is derived from PowerPC code (timebase clock frequency).
82 * On MIPS it returns the number of timer ticks per second.
83 */
84 ulong get_tbclk(void)
85 {
86 return CONFIG_SYS_HZ;
87 }