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9b07773f GL |
1 | /* |
2 | * (C) Copyright 2003 | |
3 | * Texas Instruments <www.ti.com> | |
4 | * | |
5 | * (C) Copyright 2002 | |
6 | * Sysgo Real-Time Solutions, GmbH <www.elinos.com> | |
7 | * Marius Groeger <mgroeger@sysgo.de> | |
8 | * | |
9 | * (C) Copyright 2002 | |
10 | * Sysgo Real-Time Solutions, GmbH <www.elinos.com> | |
11 | * Alex Zuepke <azu@sysgo.de> | |
12 | * | |
13 | * (C) Copyright 2002-2004 | |
14 | * Gary Jennejohn, DENX Software Engineering, <gj@denx.de> | |
15 | * | |
16 | * (C) Copyright 2004 | |
17 | * Philippe Robin, ARM Ltd. <philippe.robin@arm.com> | |
18 | * | |
19 | * (C) Copyright 2008 | |
20 | * Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de> | |
21 | * | |
22 | * See file CREDITS for list of people who contributed to this | |
23 | * project. | |
24 | * | |
25 | * This program is free software; you can redistribute it and/or | |
26 | * modify it under the terms of the GNU General Public License as | |
27 | * published by the Free Software Foundation; either version 2 of | |
28 | * the License, or (at your option) any later version. | |
29 | * | |
30 | * This program is distributed in the hope that it will be useful, | |
31 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
32 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
33 | * GNU General Public License for more details. | |
34 | * | |
35 | * You should have received a copy of the GNU General Public License | |
36 | * along with this program; if not, write to the Free Software | |
37 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, | |
38 | * MA 02111-1307 USA | |
39 | */ | |
40 | ||
41 | #include <common.h> | |
42 | #include <asm/proc-armv/ptrace.h> | |
43 | #include <s3c6400.h> | |
4265c35f | 44 | #include <div64.h> |
9b07773f GL |
45 | |
46 | static ulong timer_load_val; | |
47 | ||
48 | #define PRESCALER 167 | |
49 | ||
50 | static s3c64xx_timers *s3c64xx_get_base_timers(void) | |
51 | { | |
52 | return (s3c64xx_timers *)ELFIN_TIMER_BASE; | |
53 | } | |
54 | ||
55 | /* macro to read the 16 bit timer */ | |
56 | static inline ulong read_timer(void) | |
57 | { | |
58 | s3c64xx_timers *const timers = s3c64xx_get_base_timers(); | |
59 | ||
60 | return timers->TCNTO4; | |
61 | } | |
62 | ||
63 | /* Internal tick units */ | |
64 | /* Last decremneter snapshot */ | |
65 | static unsigned long lastdec; | |
66 | /* Monotonic incrementing timer */ | |
67 | static unsigned long long timestamp; | |
68 | ||
69 | int interrupt_init(void) | |
70 | { | |
71 | s3c64xx_timers *const timers = s3c64xx_get_base_timers(); | |
72 | ||
73 | /* use PWM Timer 4 because it has no output */ | |
74 | /* | |
75 | * We use the following scheme for the timer: | |
76 | * Prescaler is hard fixed at 167, divider at 1/4. | |
77 | * This gives at PCLK frequency 66MHz approx. 10us ticks | |
78 | * The timer is set to wrap after 100s, at 66MHz this obviously | |
79 | * happens after 10,000,000 ticks. A long variable can thus | |
80 | * keep values up to 40,000s, i.e., 11 hours. This should be | |
81 | * enough for most uses:-) Possible optimizations: select a | |
82 | * binary-friendly frequency, e.g., 1ms / 128. Also calculate | |
83 | * the prescaler automatically for other PCLK frequencies. | |
84 | */ | |
85 | timers->TCFG0 = PRESCALER << 8; | |
86 | if (timer_load_val == 0) { | |
87 | timer_load_val = get_PCLK() / PRESCALER * (100 / 4); /* 100s */ | |
88 | timers->TCFG1 = (timers->TCFG1 & ~0xf0000) | 0x20000; | |
89 | } | |
90 | ||
91 | /* load value for 10 ms timeout */ | |
92 | lastdec = timers->TCNTB4 = timer_load_val; | |
93 | /* auto load, manual update of Timer 4 */ | |
94 | timers->TCON = (timers->TCON & ~0x00700000) | TCON_4_AUTO | | |
95 | TCON_4_UPDATE; | |
96 | ||
97 | /* auto load, start Timer 4 */ | |
98 | timers->TCON = (timers->TCON & ~0x00700000) | TCON_4_AUTO | COUNT_4_ON; | |
99 | timestamp = 0; | |
100 | ||
101 | return 0; | |
102 | } | |
103 | ||
104 | /* | |
105 | * timer without interrupts | |
106 | */ | |
107 | ||
108 | /* | |
109 | * This function is derived from PowerPC code (read timebase as long long). | |
110 | * On ARM it just returns the timer value. | |
111 | */ | |
112 | unsigned long long get_ticks(void) | |
113 | { | |
114 | ulong now = read_timer(); | |
115 | ||
116 | if (lastdec >= now) { | |
117 | /* normal mode */ | |
118 | timestamp += lastdec - now; | |
119 | } else { | |
120 | /* we have an overflow ... */ | |
121 | timestamp += lastdec + timer_load_val - now; | |
122 | } | |
123 | lastdec = now; | |
124 | ||
125 | return timestamp; | |
126 | } | |
127 | ||
128 | /* | |
129 | * This function is derived from PowerPC code (timebase clock frequency). | |
130 | * On ARM it returns the number of timer ticks per second. | |
131 | */ | |
132 | ulong get_tbclk(void) | |
133 | { | |
134 | /* We overrun in 100s */ | |
135 | return (ulong)(timer_load_val / 100); | |
136 | } | |
137 | ||
138 | void reset_timer_masked(void) | |
139 | { | |
140 | /* reset time */ | |
141 | lastdec = read_timer(); | |
142 | timestamp = 0; | |
143 | } | |
144 | ||
145 | void reset_timer(void) | |
146 | { | |
147 | reset_timer_masked(); | |
148 | } | |
149 | ||
150 | ulong get_timer_masked(void) | |
151 | { | |
4265c35f | 152 | unsigned long long res = get_ticks(); |
6d0f6bcf | 153 | do_div (res, (timer_load_val / (100 * CONFIG_SYS_HZ))); |
4265c35f | 154 | return res; |
9b07773f GL |
155 | } |
156 | ||
157 | ulong get_timer(ulong base) | |
158 | { | |
159 | return get_timer_masked() - base; | |
160 | } | |
161 | ||
162 | void set_timer(ulong t) | |
163 | { | |
6d0f6bcf | 164 | timestamp = t * (timer_load_val / (100 * CONFIG_SYS_HZ)); |
9b07773f GL |
165 | } |
166 | ||
167 | void udelay(unsigned long usec) | |
168 | { | |
169 | unsigned long long tmp; | |
170 | ulong tmo; | |
171 | ||
172 | tmo = (usec + 9) / 10; | |
173 | tmp = get_ticks() + tmo; /* get current timestamp */ | |
174 | ||
175 | while (get_ticks() < tmp)/* loop till event */ | |
176 | /*NOP*/; | |
177 | } |