2 * (C) Copyright 2008,2009
3 * Graeme Russ, <graeme.russ@gmail.com>
6 * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
8 * See file CREDITS for list of people who contributed to this
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License as
13 * published by the Free Software Foundation; either version 2 of
14 * the License, or (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
30 #include <asm/i8254.h>
31 #include <asm/ibmpc.h>
33 struct timer_isr_function {
34 struct timer_isr_function *next;
35 timer_fnc_t *isr_func;
38 static struct timer_isr_function *first_timer_isr;
39 static unsigned long system_ticks;
42 * register_timer_isr() allows multiple architecture and board specific
43 * functions to be called every millisecond. Keep the execution time of
44 * each function as low as possible
46 int register_timer_isr(timer_fnc_t *isr_func)
48 struct timer_isr_function *new_func;
49 struct timer_isr_function *temp;
52 new_func = malloc(sizeof(struct timer_isr_function));
57 new_func->isr_func = isr_func;
58 new_func->next = NULL;
61 * Don't allow timer interrupts while the
62 * linked list is being modified
64 flag = disable_interrupts();
66 if (first_timer_isr == NULL) {
67 first_timer_isr = new_func;
69 temp = first_timer_isr;
70 while (temp->next != NULL)
72 temp->next = new_func;
82 * timer_isr() MUST be the registered interrupt handler for
84 void timer_isr(void *unused)
86 struct timer_isr_function *temp = first_timer_isr;
90 /* Execute each registered function */
91 while (temp != NULL) {
97 ulong get_timer(ulong base)
99 return system_ticks - base;