Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * Reset a Jazz machine. | |
4 | * | |
5 | * We don't trust the firmware so we do it the classic way by poking and | |
6 | * stabbing at the keyboard controller ... | |
7 | */ | |
8 | #include <linux/jiffies.h> | |
9 | #include <asm/jazz.h> | |
1da177e4 LT |
10 | |
11 | #define KBD_STAT_IBF 0x02 /* Keyboard input buffer full */ | |
12 | ||
13 | static void jazz_write_output(unsigned char val) | |
14 | { | |
15 | int status; | |
16 | ||
17 | do { | |
18 | status = jazz_kh->command; | |
19 | } while (status & KBD_STAT_IBF); | |
20 | jazz_kh->data = val; | |
21 | } | |
22 | ||
23 | static void jazz_write_command(unsigned char val) | |
24 | { | |
25 | int status; | |
26 | ||
27 | do { | |
28 | status = jazz_kh->command; | |
29 | } while (status & KBD_STAT_IBF); | |
30 | jazz_kh->command = val; | |
31 | } | |
32 | ||
33 | static unsigned char jazz_read_status(void) | |
34 | { | |
35 | return jazz_kh->command; | |
36 | } | |
37 | ||
38 | static inline void kb_wait(void) | |
39 | { | |
40 | unsigned long start = jiffies; | |
41 | unsigned long timeout = start + HZ/2; | |
42 | ||
43 | do { | |
44 | if (! (jazz_read_status() & 0x02)) | |
45 | return; | |
46 | } while (time_before_eq(jiffies, timeout)); | |
47 | } | |
48 | ||
49 | void jazz_machine_restart(char *command) | |
50 | { | |
51 | while(1) { | |
52 | kb_wait(); | |
49a89efb | 53 | jazz_write_command(0xd1); |
1da177e4 | 54 | kb_wait(); |
49a89efb | 55 | jazz_write_output(0x00); |
1da177e4 LT |
56 | } |
57 | } |