1 /*
2 * (C) Copyright 2002
3 * Daniel Engstr�m, Omicron Ceti AB <daniel@omicron.se>.
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 /* stuff specific for the sc520, but independent of implementation */
25
26 #include <common.h>
27 #include <asm/io.h>
28 #include <asm/interrupt.h>
29 #include <asm/ic/sc520.h>
30
sc520_timer_isr(void)31 void sc520_timer_isr(void)
32 {
33 /* Ack the GP Timer Interrupt */
34 writeb(0x02, &sc520_mmcr->gptmrsta);
35 }
36
timer_init(void)37 int timer_init(void)
38 {
39 /* Register the SC520 specific timer interrupt handler */
40 register_timer_isr (sc520_timer_isr);
41
42 /* Install interrupt handler for GP Timer 1 */
43 irq_install_handler (0, timer_isr, NULL);
44
45 /* Map GP Timer 1 to Master PIC IR0 */
46 writeb(0x01, &sc520_mmcr->gp_tmr_int_map[1]);
47
48 /* Disable GP Timers 1 & 2 - Allow configuration writes */
49 writew(0x4000, &sc520_mmcr->gptmr1ctl);
50 writew(0x4000, &sc520_mmcr->gptmr2ctl);
51
52 /* Reset GP Timers 1 & 2 */
53 writew(0x0000, &sc520_mmcr->gptmr1cnt);
54 writew(0x0000, &sc520_mmcr->gptmr2cnt);
55
56 /* Setup GP Timer 2 as a 100kHz (10us) prescaler */
57 writew(83, &sc520_mmcr->gptmr2maxcmpa);
58 writew(0xc001, &sc520_mmcr->gptmr2ctl);
59
60 /* Setup GP Timer 1 as a 1000 Hz (1ms) interrupt generator */
61 writew(100, &sc520_mmcr->gptmr1maxcmpa);
62 writew(0xe009, &sc520_mmcr->gptmr1ctl);
63
64 unmask_irq (0);
65
66 /* Clear the GP Timer 1 status register to get the show rolling*/
67 writeb(0x02, &sc520_mmcr->gptmrsta);
68
69 return 0;
70 }
71
72 /* Allow boards to override udelay implementation */
73 void __udelay(unsigned long usec)
74 __attribute__((weak, alias("sc520_udelay")));
75
sc520_udelay(unsigned long usec)76 void sc520_udelay(unsigned long usec)
77 {
78 int m = 0;
79 long u;
80 long temp;
81
82 temp = readw(&sc520_mmcr->swtmrmilli);
83 temp = readw(&sc520_mmcr->swtmrmicro);
84
85 do {
86 m += readw(&sc520_mmcr->swtmrmilli);
87 u = readw(&sc520_mmcr->swtmrmicro) + (m * 1000);
88 } while (u < usec);
89 }
90