xref: /openbmc/u-boot/arch/microblaze/cpu/timer.c (revision 150c2493)
1 /*
2  * (C) Copyright 2007 Michal Simek
3  *
4  * Michal  SIMEK <monstr@monstr.eu>
5  *
6  * See file CREDITS for list of people who contributed to this
7  * project.
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License as
11  * published by the Free Software Foundation; either version 2 of
12  * the License, or (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
22  * MA 02111-1307 USA
23  */
24 
25 #include <common.h>
26 #include <asm/microblaze_timer.h>
27 #include <asm/microblaze_intc.h>
28 
29 volatile int timestamp = 0;
30 microblaze_timer_t *tmr;
31 
32 ulong get_timer (ulong base)
33 {
34 	if (tmr)
35 		return timestamp - base;
36 	return timestamp++ - base;
37 }
38 
39 void __udelay(unsigned long usec)
40 {
41 	u32 i;
42 
43 	if (tmr) {
44 		i = get_timer(0);
45 		while ((get_timer(0) - i) < (usec / 1000))
46 			;
47 	} else {
48 		for (i = 0; i < (usec * XILINX_CLOCK_FREQ / 10000000); i++)
49 			;
50 	}
51 }
52 
53 static void timer_isr(void *arg)
54 {
55 	timestamp++;
56 	tmr->control = tmr->control | TIMER_INTERRUPT;
57 }
58 
59 int timer_init (void)
60 {
61 	int irq = -1;
62 	u32 preload = 0;
63 	u32 ret = 0;
64 
65 #if defined(CONFIG_SYS_TIMER_0_ADDR) && defined(CONFIG_SYS_INTC_0_NUM)
66 	preload = XILINX_CLOCK_FREQ / CONFIG_SYS_HZ;
67 	irq = CONFIG_SYS_TIMER_0_IRQ;
68 	tmr = (microblaze_timer_t *) (CONFIG_SYS_TIMER_0_ADDR);
69 #endif
70 
71 	if (tmr && preload && irq >= 0) {
72 		tmr->loadreg = preload;
73 		tmr->control = TIMER_INTERRUPT | TIMER_RESET;
74 		tmr->control = TIMER_ENABLE | TIMER_ENABLE_INTR |\
75 					TIMER_RELOAD | TIMER_DOWN_COUNT;
76 		timestamp = 0;
77 		ret = install_interrupt_handler (irq, timer_isr, (void *)tmr);
78 		if (ret)
79 			tmr = NULL;
80 	}
81 
82 	/* No problem if timer is not found/initialized */
83 	return 0;
84 }
85 
86 /*
87  * This function is derived from PowerPC code (read timebase as long long).
88  * On Microblaze it just returns the timer value.
89  */
90 unsigned long long get_ticks(void)
91 {
92 	return get_timer(0);
93 }
94 
95 /*
96  * This function is derived from PowerPC code (timebase clock frequency).
97  * On Microblaze it returns the number of timer ticks per second.
98  */
99 ulong get_tbclk(void)
100 {
101 	return CONFIG_SYS_HZ;
102 }
103