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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 
jazz_write_output(unsigned char val)12 static 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 
jazz_write_command(unsigned char val)22 static 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 
jazz_read_status(void)32 static unsigned char jazz_read_status(void)
33 {
34 	return jazz_kh->command;
35 }
36 
kb_wait(void)37 static 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 
jazz_machine_restart(char * command)48 void 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 }
57