1 /*
2 * Kernel Debugger Architecture Dependent Console I/O handler
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License.
6 *
7 * Copyright (c) 1999-2006 Silicon Graphics, Inc. All Rights Reserved.
8 * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
9 */
10
11 #include <linux/kdb.h>
12 #include <linux/keyboard.h>
13 #include <linux/ctype.h>
14 #include <linux/io.h>
15
16 #include "kdb_private.h"
17
18 /* Keyboard Controller Registers on normal PCs. */
19
20 #define KBD_STATUS_REG 0x64 /* Status register (R) */
21 #define KBD_DATA_REG 0x60 /* Keyboard data register (R/W) */
22
23 /* Status Register Bits */
24
25 #define KBD_STAT_OBF 0x01 /* Keyboard output buffer full */
26 #define KBD_STAT_MOUSE_OBF 0x20 /* Mouse output buffer full */
27
28 static int kbd_exists;
29 static int kbd_last_ret;
30
31 /*
32 * Check if the keyboard controller has a keypress for us.
33 * Some parts (Enter Release, LED change) are still blocking polled here,
34 * but hopefully they are all short.
35 */
36 int kdb_get_kbd_char(void)
37 {
38 int scancode, scanstatus;
39 static int shift_lock; /* CAPS LOCK state (0-off, 1-on) */
40 static int shift_key; /* Shift next keypress */
41 static int ctrl_key;
42 u_short keychar;
43
44 if (KDB_FLAG(NO_I8042) || KDB_FLAG(NO_VT_CONSOLE) ||
45 (inb(KBD_STATUS_REG) == 0xff && inb(KBD_DATA_REG) == 0xff)) {
46 kbd_exists = 0;
47 return -1;
48 }
49 kbd_exists = 1;
50
51 if ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0)
52 return -1;
53
54 /*
55 * Fetch the scancode
56 */
57 scancode = inb(KBD_DATA_REG);
58 scanstatus = inb(KBD_STATUS_REG);
59
60 /*
61 * Ignore mouse events.
62 */
63 if (scanstatus & KBD_STAT_MOUSE_OBF)
64 return -1;
65
66 /*
67 * Ignore release, trigger on make
68 * (except for shift keys, where we want to
69 * keep the shift state so long as the key is
70 * held down).
71 */
72
73 if (((scancode&0x7f) == 0x2a) || ((scancode&0x7f) == 0x36)) {
74 /*
75 * Next key may use shift table
76 */
77 if ((scancode & 0x80) == 0)
78 shift_key = 1;
79 else
80 shift_key = 0;
81 return -1;
82 }
83
84 if ((scancode&0x7f) == 0x1d) {
85 /*
86 * Left ctrl key
87 */
88 if ((scancode & 0x80) == 0)
89 ctrl_key = 1;
90 else
91 ctrl_key = 0;
92 return -1;
93 }
94
95 if ((scancode & 0x80) != 0) {
96 if (scancode == 0x9c)
97 kbd_last_ret = 0;
98 return -1;
99 }
100
101 scancode &= 0x7f;
102
103 /*
104 * Translate scancode
105 */
106
107 if (scancode == 0x3a) {
108 /*
109 * Toggle caps lock
110 */
111 shift_lock ^= 1;
112
113 #ifdef KDB_BLINK_LED
114 kdb_toggleled(0x4);
115 #endif
116 return -1;
117 }
118
119 if (scancode == 0x0e) {
120 /*
121 * Backspace
122 */
123 return 8;
124 }
125
126 /* Special Key */
127 switch (scancode) {
128 case 0xF: /* Tab */
129 return 9;
130 case 0x53: /* Del */
131 return 4;
132 case 0x47: /* Home */
133 return 1;
134 case 0x4F: /* End */
135 return 5;
136 case 0x4B: /* Left */
137 return 2;
138 case 0x48: /* Up */
139 return 16;
140 case 0x50: /* Down */
141 return 14;
142 case 0x4D: /* Right */
143 return 6;
144 }
145
146 if (scancode == 0xe0)
147 return -1;
148
149 /*
150 * For Japanese 86/106 keyboards
151 * See comment in drivers/char/pc_keyb.c.
152 * - Masahiro Adegawa
153 */
154 if (scancode == 0x73)
155 scancode = 0x59;
156 else if (scancode == 0x7d)
157 scancode = 0x7c;
158
159 if (!shift_lock && !shift_key && !ctrl_key) {
160 keychar = plain_map[scancode];
161 } else if ((shift_lock || shift_key) && key_maps[1]) {
162 keychar = key_maps[1][scancode];
163 } else if (ctrl_key && key_maps[4]) {
164 keychar = key_maps[4][scancode];
165 } else {
166 keychar = 0x0020;
167 kdb_printf("Unknown state/scancode (%d)\n", scancode);
168 }
169 keychar &= 0x0fff;
170 if (keychar == '\t')
171 keychar = ' ';
172 switch (KTYP(keychar)) {
173 case KT_LETTER:
174 case KT_LATIN:
175 if (isprint(keychar))
176 break; /* printable characters */
177 fallthrough;
178 case KT_SPEC:
179 if (keychar == K_ENTER)
180 break;
181 fallthrough;
182 default:
183 return -1; /* ignore unprintables */
184 }
185
186 if (scancode == 0x1c) {
187 kbd_last_ret = 1;
188 return 13;
189 }
190
191 return keychar & 0xff;
192 }
193 EXPORT_SYMBOL_GPL(kdb_get_kbd_char);
194
195 /*
196 * Best effort cleanup of ENTER break codes on leaving KDB. Called on
197 * exiting KDB, when we know we processed an ENTER or KP ENTER scan
198 * code.
199 */
200 void kdb_kbd_cleanup_state(void)
201 {
202 int scancode, scanstatus;
203
204 /*
205 * Nothing to clean up, since either
206 * ENTER was never pressed, or has already
207 * gotten cleaned up.
208 */
209 if (!kbd_last_ret)
210 return;
211
212 kbd_last_ret = 0;
213 /*
214 * Enter key. Need to absorb the break code here, lest it gets
215 * leaked out if we exit KDB as the result of processing 'g'.
216 *
217 * This has several interesting implications:
218 * + Need to handle KP ENTER, which has break code 0xe0 0x9c.
219 * + Need to handle repeat ENTER and repeat KP ENTER. Repeats
220 * only get a break code at the end of the repeated
221 * sequence. This means we can't propagate the repeated key
222 * press, and must swallow it away.
223 * + Need to handle possible PS/2 mouse input.
224 * + Need to handle mashed keys.
225 */
226
227 while (1) {
228 while ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0)
229 cpu_relax();
230
231 /*
232 * Fetch the scancode.
233 */
234 scancode = inb(KBD_DATA_REG);
235 scanstatus = inb(KBD_STATUS_REG);
236
237 /*
238 * Skip mouse input.
239 */
240 if (scanstatus & KBD_STAT_MOUSE_OBF)
241 continue;
242
243 /*
244 * If we see 0xe0, this is either a break code for KP
245 * ENTER, or a repeat make for KP ENTER. Either way,
246 * since the second byte is equivalent to an ENTER,
247 * skip the 0xe0 and try again.
248 *
249 * If we see 0x1c, this must be a repeat ENTER or KP
250 * ENTER (and we swallowed 0xe0 before). Try again.
251 *
252 * We can also see make and break codes for other keys
253 * mashed before or after pressing ENTER. Thus, if we
254 * see anything other than 0x9c, we have to try again.
255 *
256 * Note, if you held some key as ENTER was depressed,
257 * that break code would get leaked out.
258 */
259 if (scancode != 0x9c)
260 continue;
261
262 return;
263 }
264 }
265
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