summaryrefslogtreecommitdiffstats
path: root/arch/x86/boot/video.c
blob: 05111bb8d018e38c71ae278ee0a78ccff76e34e2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
/* -*- linux-c -*- ------------------------------------------------------- *
 *
 *   Copyright (C) 1991, 1992 Linus Torvalds
 *   Copyright 2007 rPath, Inc. - All Rights Reserved
 *   Copyright 2009 Intel Corporation; author H. Peter Anvin
 *
 *   This file is part of the Linux kernel, and is made available under
 *   the terms of the GNU General Public License version 2.
 *
 * ----------------------------------------------------------------------- */

/*
 * Select video mode
 */

#include "boot.h"
#include "video.h"
#include "vesa.h"

static u16 video_segment;

static void store_cursor_position(void)
{
	struct biosregs ireg, oreg;

	initregs(&ireg);
	ireg.ah = 0x03;
	intcall(0x10, &ireg, &oreg);

	boot_params.screen_info.orig_x = oreg.dl;
	boot_params.screen_info.orig_y = oreg.dh;

	if (oreg.ch & 0x20)
		boot_params.screen_info.flags |= VIDEO_FLAGS_NOCURSOR;

	if ((oreg.ch & 0x1f) > (oreg.cl & 0x1f))
		boot_params.screen_info.flags |= VIDEO_FLAGS_NOCURSOR;
}

static void store_video_mode(void)
{
	struct biosregs ireg, oreg;

	/* N.B.: the saving of the video page here is a bit silly,
	   since we pretty much assume page 0 everywhere. */
	initregs(&ireg);
	ireg.ah = 0x0f;
	intcall(0x10, &ireg, &oreg);

	/* Not all BIOSes are clean with respect to the top bit */
	boot_params.screen_info.orig_video_mode = oreg.al & 0x7f;
	boot_params.screen_info.orig_video_page = oreg.bh;
}

/*
 * Store the video mode parameters for later usage by the kernel.
 * This is done by asking the BIOS except for the rows/columns
 * parameters in the default 80x25 mode -- these are set directly,
 * because some very obscure BIOSes supply insane values.
 */
static void store_mode_params(void)
{
	u16 font_size;
	int x, y;

	/* For graphics mode, it is up to the mode-setting driver
	   (currently only video-vesa.c) to store the parameters */
	if (graphic_mode)
		return;

	store_cursor_position();
	store_video_mode();

	if (boot_params.screen_info.orig_video_mode == 0x07) {
		/* MDA, HGC, or VGA in monochrome mode */
		video_segment = 0xb000;
	} else {
		/* CGA, EGA, VGA and so forth */
		video_segment = 0xb800;
	}

	set_fs(0);
	font_size = rdfs16(0x485); /* Font size, BIOS area */
	boot_params.screen_info.orig_video_points = font_size;

	x = rdfs16(0x44a);
	y = (adapter == ADAPTER_CGA) ? 25 : rdfs8(0x484)+1;

	if (force_x)
		x = force_x;
	if (force_y)
		y = force_y;

	boot_params.screen_info.orig_video_cols  = x;
	boot_params.screen_info.orig_video_lines = y;
}

static unsigned int get_entry(void)
{
	char entry_buf[4];
	int i, len = 0;
	int key;
	unsigned int v;

	do {
		key = getchar();

		if (key == '\b') {
			if (len > 0) {
				puts("\b \b");
				len--;
			}
		} else if ((key >= '0' && key <= '9') ||
			   (key >= 'A' && key <= 'Z') ||
			   (key >= 'a' && key <= 'z')) {
			if (len < sizeof entry_buf) {
				entry_buf[len++] = key;
				putchar(key);
			}
		}
	} while (key != '\r');
	putchar('\n');

	if (len == 0)
		return VIDEO_CURRENT_MODE; /* Default */

	v = 0;
	for (i = 0; i < len; i++) {
		v <<= 4;
		key = entry_buf[i] | 0x20;
		v += (key > '9') ? key-'a'+10 : key-'0';
	}

	return v;
}

static void display_menu(void)
{
	struct card_info *card;
	struct mode_info *mi;
	char ch;
	int i;
	int nmodes;
	int modes_per_line;
	int col;

	nmodes = 0;
	for (card = video_cards; card < video_cards_end; card++)
		nmodes += card->nmodes;

	modes_per_line = 1;
	if (nmodes >= 20)
		modes_per_line = 3;

	for (col = 0; col < modes_per_line; col++)
		puts("Mode: Resolution:  Type: ");
	putchar('\n');

	col = 0;
	ch = '0';
	for (card = video_cards; card < video_cards_end; card++) {
		mi = card->modes;
		for (i = 0; i < card->nmodes; i++, mi++) {
			char resbuf[32];
			int visible = mi->x && mi->y;
			u16 mode_id = mi->mode ? mi->mode :
				(mi->y << 8)+mi->x;

			if (!visible)
				continue; /* Hidden mode */

			if (mi->depth)
				sprintf(resbuf, "%dx%d", mi->y, mi->depth);
			else
				sprintf(resbuf, "%d", mi->y);

			printf("%c %03X %4dx%-7s %-6s",
			       ch, mode_id, mi->x, resbuf, card->card_name);
			col++;
			if (col >= modes_per_line) {
				putchar('\n');
				col = 0;
			}

			if (ch == '9')
				ch = 'a';
			else if (ch == 'z' || ch == ' ')
				ch = ' '; /* Out of keys... */
			else
				ch++;
		}
	}
	if (col)
		putchar('\n');
}

#define H(x)	((x)-'a'+10)
#define SCAN	((H('s')<<12)+(H('c')<<8)+(H('a')<<4)+H('n'))

static unsigned int mode_menu(void)
{
	int key;
	unsigned int sel;

	puts("Press <ENTER> to see video modes available, "
	     "<SPACE> to continue, or wait 30 sec\n");

	kbd_flush();
	while (1) {
		key = getchar_timeout();
		if (key == ' ' || key == 0)
			return VIDEO_CURRENT_MODE; /* Default */
		if (key == '\r')
			break;
		putchar('\a');	/* Beep! */
	}


	for (;;) {
		display_menu();

		puts("Enter a video mode or \"scan\" to scan for "
		     "additional modes: ");
		sel = get_entry();
		if (sel != SCAN)
			return sel;

		probe_cards(1);
	}
}

/* Save screen content to the heap */
static struct saved_screen {
	int x, y;
	int curx, cury;
	u16 *data;
} saved;

static void save_screen(void)
{
	/* Should be called after store_mode_params() */
	saved.x = boot_params.screen_info.orig_video_cols;
	saved.y = boot_params.screen_info.orig_video_lines;
	saved.curx = boot_params.screen_info.orig_x;
	saved.cury = boot_params.screen_info.orig_y;

	if (!heap_free(saved.x*saved.y*sizeof(u16)+512))
		return;		/* Not enough heap to save the screen */

	saved.data = GET_HEAP(u16, saved.x*saved.y);

	set_fs(video_segment);
	copy_from_fs(saved.data, 0, saved.x*saved.y*sizeof(u16));
}

static void restore_screen(void)
{
	/* Should be called after store_mode_params() */
	int xs = boot_params.screen_info.orig_video_cols;
	int ys = boot_params.screen_info.orig_video_lines;
	int y;
	addr_t dst = 0;
	u16 *src = saved.data;
	struct biosregs ireg;

	if (graphic_mode)
		return;		/* Can't restore onto a graphic mode */

	if (!src)
		return;		/* No saved screen contents */

	/* Restore screen contents */

	set_fs(video_segment);
	for (y = 0; y < ys; y++) {
		int npad;

		if (y < saved.y) {
			int copy = (xs < saved.x) ? xs : saved.x;
			copy_to_fs(dst, src, copy*sizeof(u16));
			dst += copy*sizeof(u16);
			src += saved.x;
			npad = (xs < saved.x) ? 0 : xs-saved.x;
		} else {
			npad = xs;
		}

		/* Writes "npad" blank characters to
		   video_segment:dst and advances dst */
		asm volatile("pushw %%es ; "
			     "movw %2,%%es ; "
			     "shrw %%cx ; "
			     "jnc 1f ; "
			     "stosw \n\t"
			     "1: rep;stosl ; "
			     "popw %%es"
			     : "+D" (dst), "+c" (npad)
			     : "bdS" (video_segment),
			       "a" (0x07200720));
	}

	/* Restore cursor position */
	if (saved.curx >= xs)
		saved.curx = xs-1;
	if (saved.cury >= ys)
		saved.cury = ys-1;

	initregs(&ireg);
	ireg.ah = 0x02;		/* Set cursor position */
	ireg.dh = saved.cury;
	ireg.dl = saved.curx;
	intcall(0x10, &ireg, NULL);

	store_cursor_position();
}

void set_video(void)
{
	u16 mode = boot_params.hdr.vid_mode;

	RESET_HEAP();

	store_mode_params();
	save_screen();
	probe_cards(0);

	for (;;) {
		if (mode == ASK_VGA)
			mode = mode_menu();

		if (!set_mode(mode))
			break;

		printf("Undefined video mode number: %x\n", mode);
		mode = ASK_VGA;
	}
	boot_params.hdr.vid_mode = mode;
	vesa_store_edid();
	store_mode_params();

	if (do_restore)
		restore_screen();
}