summaryrefslogtreecommitdiffstats
path: root/arch/x86/boot/video-vga.c
blob: 95d86ce0421c84dd647f26f34cd65fc9f0143d3e (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
/* -*- linux-c -*- ------------------------------------------------------- *
 *
 *   Copyright (C) 1991, 1992 Linus Torvalds
 *   Copyright 2007 rPath, Inc. - All Rights Reserved
 *
 *   This file is part of the Linux kernel, and is made available under
 *   the terms of the GNU General Public License version 2.
 *
 * ----------------------------------------------------------------------- */

/*
 * Common all-VGA modes
 */

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

static struct mode_info vga_modes[] = {
	{ VIDEO_80x25,  80, 25, 0 },
	{ VIDEO_8POINT, 80, 50, 0 },
	{ VIDEO_80x43,  80, 43, 0 },
	{ VIDEO_80x28,  80, 28, 0 },
	{ VIDEO_80x30,  80, 30, 0 },
	{ VIDEO_80x34,  80, 34, 0 },
	{ VIDEO_80x60,  80, 60, 0 },
};

static struct mode_info ega_modes[] = {
	{ VIDEO_80x25,  80, 25, 0 },
	{ VIDEO_8POINT, 80, 43, 0 },
};

static struct mode_info cga_modes[] = {
	{ VIDEO_80x25,  80, 25, 0 },
};

static __videocard video_vga;

/* Set basic 80x25 mode */
static u8 vga_set_basic_mode(void)
{
	u16 ax;
	u8 rows;
	u8 mode;

#ifdef CONFIG_VIDEO_400_HACK
	if (adapter >= ADAPTER_VGA) {
		asm volatile(INT10
			     : : "a" (0x1202), "b" (0x0030)
			     : "ecx", "edx", "esi", "edi");
	}
#endif

	ax = 0x0f00;
	asm volatile(INT10
		     : "+a" (ax)
		     : : "ebx", "ecx", "edx", "esi", "edi");

	mode = (u8)ax;

	set_fs(0);
	rows = rdfs8(0x484);	/* rows minus one */

#ifndef CONFIG_VIDEO_400_HACK
	if ((ax == 0x5003 || ax == 0x5007) &&
	    (rows == 0 || rows == 24))
		return mode;
#endif

	if (mode != 3 && mode != 7)
		mode = 3;

	/* Set the mode */
	ax = mode;
	asm volatile(INT10
		     : "+a" (ax)
		     : : "ebx", "ecx", "edx", "esi", "edi");
	do_restore = 1;
	return mode;
}

static void vga_set_8font(void)
{
	/* Set 8x8 font - 80x43 on EGA, 80x50 on VGA */

	/* Set 8x8 font */
	asm volatile(INT10 : : "a" (0x1112), "b" (0));

	/* Use alternate print screen */
	asm volatile(INT10 : : "a" (0x1200), "b" (0x20));

	/* Turn off cursor emulation */
	asm volatile(INT10 : : "a" (0x1201), "b" (0x34));

	/* Cursor is scan lines 6-7 */
	asm volatile(INT10 : : "a" (0x0100), "c" (0x0607));
}

static void vga_set_14font(void)
{
	/* Set 9x14 font - 80x28 on VGA */

	/* Set 9x14 font */
	asm volatile(INT10 : : "a" (0x1111), "b" (0));

	/* Turn off cursor emulation */
	asm volatile(INT10 : : "a" (0x1201), "b" (0x34));

	/* Cursor is scan lines 11-12 */
	asm volatile(INT10 : : "a" (0x0100), "c" (0x0b0c));
}

static void vga_set_80x43(void)
{
	/* Set 80x43 mode on VGA (not EGA) */

	/* Set 350 scans */
	asm volatile(INT10 : : "a" (0x1201), "b" (0x30));

	/* Reset video mode */
	asm volatile(INT10 : : "a" (0x0003));

	vga_set_8font();
}

/* I/O address of the VGA CRTC */
u16 vga_crtc(void)
{
	return (inb(0x3cc) & 1) ? 0x3d4 : 0x3b4;
}

static void vga_set_480_scanlines(int lines)
{
	u16 crtc;		/* CRTC base address */
	u8  csel;		/* CRTC miscellaneous output register */
	u8  ovfw;		/* CRTC overflow register */
	int end = lines-1;

	crtc = vga_crtc();

	ovfw = 0x3c | ((end >> (8-1)) & 0x02) | ((end >> (9-6)) & 0x40);

	out_idx(0x0c, crtc, 0x11); /* Vertical sync end, unlock CR0-7 */
	out_idx(0x0b, crtc, 0x06); /* Vertical total */
	out_idx(ovfw, crtc, 0x07); /* Vertical overflow */
	out_idx(0xea, crtc, 0x10); /* Vertical sync start */
	out_idx(end,  crtc, 0x12); /* Vertical display end */
	out_idx(0xe7, crtc, 0x15); /* Vertical blank start */
	out_idx(0x04, crtc, 0x16); /* Vertical blank end */
	csel = inb(0x3cc);
	csel &= 0x0d;
	csel |= 0xe2;
	outb(csel, 0x3c2);
}

static void vga_set_80x30(void)
{
	vga_set_480_scanlines(30*16);
}

static void vga_set_80x34(void)
{
	vga_set_14font();
	vga_set_480_scanlines(34*14);
}

static void vga_set_80x60(void)
{
	vga_set_8font();
	vga_set_480_scanlines(60*8);
}

static int vga_set_mode(struct mode_info *mode)
{
	/* Set the basic mode */
	vga_set_basic_mode();

	/* Override a possibly broken BIOS */
	force_x = mode->x;
	force_y = mode->y;

	switch (mode->mode) {
	case VIDEO_80x25:
		break;
	case VIDEO_8POINT:
		vga_set_8font();
		break;
	case VIDEO_80x43:
		vga_set_80x43();
		break;
	case VIDEO_80x28:
		vga_set_14font();
		break;
	case VIDEO_80x30:
		vga_set_80x30();
		break;
	case VIDEO_80x34:
		vga_set_80x34();
		break;
	case VIDEO_80x60:
		vga_set_80x60();
		break;
	}

	return 0;
}

/*
 * Note: this probe includes basic information required by all
 * systems.  It should be executed first, by making sure
 * video-vga.c is listed first in the Makefile.
 */
static int vga_probe(void)
{
	u16 ega_bx;

	static const char *card_name[] = {
		"CGA/MDA/HGC", "EGA", "VGA"
	};
	static struct mode_info *mode_lists[] = {
		cga_modes,
		ega_modes,
		vga_modes,
	};
	static int mode_count[] = {
		sizeof(cga_modes)/sizeof(struct mode_info),
		sizeof(ega_modes)/sizeof(struct mode_info),
		sizeof(vga_modes)/sizeof(struct mode_info),
	};
	u8 vga_flag;

	asm(INT10
	    : "=b" (ega_bx)
	    : "a" (0x1200), "b" (0x10) /* Check EGA/VGA */
	    : "ecx", "edx", "esi", "edi");

#ifndef _WAKEUP
	boot_params.screen_info.orig_video_ega_bx = ega_bx;
#endif

	/* If we have MDA/CGA/HGC then BL will be unchanged at 0x10 */
	if ((u8)ega_bx != 0x10) {
		/* EGA/VGA */
		asm(INT10
		    : "=a" (vga_flag)
		    : "a" (0x1a00)
		    : "ebx", "ecx", "edx", "esi", "edi");

		if (vga_flag == 0x1a) {
			adapter = ADAPTER_VGA;
#ifndef _WAKEUP
			boot_params.screen_info.orig_video_isVGA = 1;
#endif
		} else {
			adapter = ADAPTER_EGA;
		}
	} else {
		adapter = ADAPTER_CGA;
	}

	video_vga.modes = mode_lists[adapter];
	video_vga.card_name = card_name[adapter];
	return mode_count[adapter];
}

static __videocard video_vga = {
	.card_name	= "VGA",
	.probe		= vga_probe,
	.set_mode	= vga_set_mode,
};
OpenPOWER on IntegriCloud