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rename CFG_ macros to CONFIG_SYS
[people/ms/u-boot.git] / lib_ppc / time.c
1 /*
2 * (C) Copyright 2000, 2001
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
26 #ifndef CONFIG_WD_PERIOD
27 # define CONFIG_WD_PERIOD (10 * 1000 * 1000) /* 10 seconds default*/
28 #endif
29
30 /* ------------------------------------------------------------------------- */
31
32 /*
33 * This function is intended for SHORT delays only.
34 * It will overflow at around 10 seconds @ 400MHz,
35 * or 20 seconds @ 200MHz.
36 */
37 unsigned long usec2ticks(unsigned long usec)
38 {
39 ulong ticks;
40
41 if (usec < 1000) {
42 ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000;
43 } else {
44 ticks = ((usec / 10) * (get_tbclk() / 100000));
45 }
46
47 return (ticks);
48 }
49
50 /* ------------------------------------------------------------------------- */
51
52 /*
53 * We implement the delay by converting the delay (the number of
54 * microseconds to wait) into a number of time base ticks; then we
55 * watch the time base until it has incremented by that amount.
56 */
57 void udelay(unsigned long usec)
58 {
59 ulong ticks, kv;
60
61 do {
62 kv = usec > CONFIG_WD_PERIOD ? CONFIG_WD_PERIOD : usec;
63 ticks = usec2ticks (kv);
64 wait_ticks (ticks);
65 usec -= kv;
66 } while(usec);
67 }
68
69 /* ------------------------------------------------------------------------- */
70 #ifndef CONFIG_NAND_SPL
71 unsigned long ticks2usec(unsigned long ticks)
72 {
73 ulong tbclk = get_tbclk();
74
75 /* usec = ticks * 1000000 / tbclk
76 * Multiplication would overflow at ~4.2e3 ticks,
77 * so we break it up into
78 * usec = ( ( ticks * 1000) / tbclk ) * 1000;
79 */
80 ticks *= 1000L;
81 ticks /= tbclk;
82 ticks *= 1000L;
83
84 return ((ulong)ticks);
85 }
86 #endif
87 /* ------------------------------------------------------------------------- */
88
89 int init_timebase (void)
90 {
91 #if defined(CONFIG_5xx) || defined(CONFIG_8xx)
92 volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
93
94 /* unlock */
95 immap->im_sitk.sitk_tbk = KAPWR_KEY;
96 #endif
97
98 /* reset */
99 asm ("li 3,0 ; mttbu 3 ; mttbl 3 ;");
100
101 #if defined(CONFIG_5xx) || defined(CONFIG_8xx)
102 /* enable */
103 immap->im_sit.sit_tbscr |= TBSCR_TBE;
104 #endif
105 return (0);
106 }
107 /* ------------------------------------------------------------------------- */