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 */
23
24 #include <common.h>
25 #include <asm/mipsregs.h>
26
27 static unsigned long timestamp;
28
29 /* how many counter cycles in a jiffy */
30 #define CYCLES_PER_JIFFY (CONFIG_SYS_MIPS_TIMER_FREQ + CONFIG_SYS_HZ / 2) / CONFIG_SYS_HZ
31
32 /*
33 * timer without interrupts
34 */
35
timer_init(void)36 int timer_init(void)
37 {
38 /* Set up the timer for the first expiration. */
39 timestamp = 0;
40 write_c0_compare(read_c0_count() + CYCLES_PER_JIFFY);
41
42 return 0;
43 }
44
reset_timer(void)45 void reset_timer(void)
46 {
47 timestamp = 0;
48 write_c0_compare(read_c0_count() + CYCLES_PER_JIFFY);
49 }
50
get_timer(ulong base)51 ulong get_timer(ulong base)
52 {
53 unsigned int count;
54 unsigned int expirelo = read_c0_compare();
55
56 /* Check to see if we have missed any timestamps. */
57 count = read_c0_count();
58 while ((count - expirelo) < 0x7fffffff) {
59 expirelo += CYCLES_PER_JIFFY;
60 timestamp++;
61 }
62 write_c0_compare(expirelo);
63
64 return (timestamp - base);
65 }
66
set_timer(ulong t)67 void set_timer(ulong t)
68 {
69 timestamp = t;
70 write_c0_compare(read_c0_count() + CYCLES_PER_JIFFY);
71 }
72
__udelay(unsigned long usec)73 void __udelay(unsigned long usec)
74 {
75 unsigned int tmo;
76
77 tmo = read_c0_count() + (usec * (CONFIG_SYS_MIPS_TIMER_FREQ / 1000000));
78 while ((tmo - read_c0_count()) < 0x7fffffff)
79 /*NOP*/;
80 }
81
82 /*
83 * This function is derived from PowerPC code (read timebase as long long).
84 * On MIPS it just returns the timer value.
85 */
get_ticks(void)86 unsigned long long get_ticks(void)
87 {
88 return get_timer(0);
89 }
90
91 /*
92 * This function is derived from PowerPC code (timebase clock frequency).
93 * On MIPS it returns the number of timer ticks per second.
94 */
get_tbclk(void)95 ulong get_tbclk(void)
96 {
97 return CONFIG_SYS_HZ;
98 }
99