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git.ipfire.org Git - people/ms/u-boot.git/blob - cpu/arm1176/s3c64xx/interrupts.c
3 * Texas Instruments <www.ti.com>
6 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
7 * Marius Groeger <mgroeger@sysgo.de>
10 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
11 * Alex Zuepke <azu@sysgo.de>
13 * (C) Copyright 2002-2004
14 * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
17 * Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
20 * Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
22 * See file CREDITS for list of people who contributed to this
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.
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.
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,
42 #include <asm/proc-armv/ptrace.h>
46 static ulong timer_load_val
;
50 static s3c64xx_timers
*s3c64xx_get_base_timers(void)
52 return (s3c64xx_timers
*)ELFIN_TIMER_BASE
;
55 /* macro to read the 16 bit timer */
56 static inline ulong
read_timer(void)
58 s3c64xx_timers
*const timers
= s3c64xx_get_base_timers();
60 return timers
->TCNTO4
;
63 /* Internal tick units */
64 /* Last decremneter snapshot */
65 static unsigned long lastdec
;
66 /* Monotonic incrementing timer */
67 static unsigned long long timestamp
;
69 int interrupt_init(void)
71 s3c64xx_timers
*const timers
= s3c64xx_get_base_timers();
73 /* use PWM Timer 4 because it has no output */
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.
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;
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
|
97 /* auto load, start Timer 4 */
98 timers
->TCON
= (timers
->TCON
& ~0x00700000) | TCON_4_AUTO
| COUNT_4_ON
;
105 * timer without interrupts
109 * This function is derived from PowerPC code (read timebase as long long).
110 * On ARM it just returns the timer value.
112 unsigned long long get_ticks(void)
114 ulong now
= read_timer();
116 if (lastdec
>= now
) {
118 timestamp
+= lastdec
- now
;
120 /* we have an overflow ... */
121 timestamp
+= lastdec
+ timer_load_val
- now
;
129 * This function is derived from PowerPC code (timebase clock frequency).
130 * On ARM it returns the number of timer ticks per second.
132 ulong
get_tbclk(void)
134 /* We overrun in 100s */
135 return (ulong
)(timer_load_val
/ 100);
138 void reset_timer_masked(void)
141 lastdec
= read_timer();
145 void reset_timer(void)
147 reset_timer_masked();
150 ulong
get_timer_masked(void)
152 unsigned long long res
= get_ticks();
153 do_div (res
, (timer_load_val
/ (100 * CONFIG_SYS_HZ
)));
157 ulong
get_timer(ulong base
)
159 return get_timer_masked() - base
;
162 void set_timer(ulong t
)
164 timestamp
= t
* (timer_load_val
/ (100 * CONFIG_SYS_HZ
));
167 void udelay(unsigned long usec
)
169 unsigned long long tmp
;
172 tmo
= (usec
+ 9) / 10;
173 tmp
= get_ticks() + tmo
; /* get current timestamp */
175 while (get_ticks() < tmp
)/* loop till event */