/arch/mips/jazz/reset.c

 1/*
 2 * Reset a Jazz machine.
 3 *
 4 * We don't trust the firmware so we do it the classic way by poking and
 5 * stabbing at the keyboard controller ...
 6 */
 7#include <linux/jiffies.h>
 8#include <asm/jazz.h>
 9
10#define KBD_STAT_IBF		0x02	/* Keyboard input buffer full */
11
12static void jazz_write_output(unsigned char val)
13{
14	int status;
15
16	do {
17		status = jazz_kh->command;
18	} while (status & KBD_STAT_IBF);
19	jazz_kh->data = val;
20}
21
22static void jazz_write_command(unsigned char val)
23{
24	int status;
25
26	do {
27		status = jazz_kh->command;
28	} while (status & KBD_STAT_IBF);
29	jazz_kh->command = val;
30}
31
32static unsigned char jazz_read_status(void)
33{
34	return jazz_kh->command;
35}
36
37static inline void kb_wait(void)
38{
39	unsigned long start = jiffies;
40	unsigned long timeout = start + HZ/2;
41
42	do {
43		if (! (jazz_read_status() & 0x02))
44			return;
45	} while (time_before_eq(jiffies, timeout));
46}
47
48void jazz_machine_restart(char *command)
49{
50	while(1) {
51		kb_wait();
52		jazz_write_command(0xd1);
53		kb_wait();
54		jazz_write_output(0x00);
55	}
56}