1// SPDX-License-Identifier: GPL-2.0-only
2/* -*- linux-c -*- ------------------------------------------------------- *
3 *
4 *   Copyright (C) 1991, 1992 Linus Torvalds
5 *   Copyright 2007 rPath, Inc. - All Rights Reserved
6 *   Copyright 2009 Intel Corporation; author H. Peter Anvin
7 *
8 * ----------------------------------------------------------------------- */
9
10/*
11 * Select video mode
12 */
13
14#include <uapi/asm/boot.h>
15
16#include "boot.h"
17#include "video.h"
18#include "vesa.h"
19
20static u16 video_segment;
21
22static void store_cursor_position(void)
23{
24	struct biosregs ireg, oreg;
25
26	initregs(&ireg);
27	ireg.ah = 0x03;
28	intcall(0x10, &ireg, &oreg);
29
30	boot_params.screen_info.orig_x = oreg.dl;
31	boot_params.screen_info.orig_y = oreg.dh;
32
33	if (oreg.ch & 0x20)
34		boot_params.screen_info.flags |= VIDEO_FLAGS_NOCURSOR;
35
36	if ((oreg.ch & 0x1f) > (oreg.cl & 0x1f))
37		boot_params.screen_info.flags |= VIDEO_FLAGS_NOCURSOR;
38}
39
40static void store_video_mode(void)
41{
42	struct biosregs ireg, oreg;
43
44	/* N.B.: the saving of the video page here is a bit silly,
45	   since we pretty much assume page 0 everywhere. */
46	initregs(&ireg);
47	ireg.ah = 0x0f;
48	intcall(0x10, &ireg, &oreg);
49
50	/* Not all BIOSes are clean with respect to the top bit */
51	boot_params.screen_info.orig_video_mode = oreg.al & 0x7f;
52	boot_params.screen_info.orig_video_page = oreg.bh;
53}
54
55/*
56 * Store the video mode parameters for later usage by the kernel.
57 * This is done by asking the BIOS except for the rows/columns
58 * parameters in the default 80x25 mode -- these are set directly,
59 * because some very obscure BIOSes supply insane values.
60 */
61static void store_mode_params(void)
62{
63	u16 font_size;
64	int x, y;
65
66	/* For graphics mode, it is up to the mode-setting driver
67	   (currently only video-vesa.c) to store the parameters */
68	if (graphic_mode)
69		return;
70
71	store_cursor_position();
72	store_video_mode();
73
74	if (boot_params.screen_info.orig_video_mode == 0x07) {
75		/* MDA, HGC, or VGA in monochrome mode */
76		video_segment = 0xb000;
77	} else {
78		/* CGA, EGA, VGA and so forth */
79		video_segment = 0xb800;
80	}
81
82	set_fs(0);
83	font_size = rdfs16(0x485); /* Font size, BIOS area */
84	boot_params.screen_info.orig_video_points = font_size;
85
86	x = rdfs16(0x44a);
87	y = (adapter == ADAPTER_CGA) ? 25 : rdfs8(0x484)+1;
88
89	if (force_x)
90		x = force_x;
91	if (force_y)
92		y = force_y;
93
94	boot_params.screen_info.orig_video_cols  = x;
95	boot_params.screen_info.orig_video_lines = y;
96}
97
98static unsigned int get_entry(void)
99{
100	char entry_buf[4];
101	int i, len = 0;
102	int key;
103	unsigned int v;
104
105	do {
106		key = getchar();
107
108		if (key == '\b') {
109			if (len > 0) {
110				puts("\b \b");
111				len--;
112			}
113		} else if ((key >= '0' && key <= '9') ||
114			   (key >= 'A' && key <= 'Z') ||
115			   (key >= 'a' && key <= 'z')) {
116			if (len < sizeof(entry_buf)) {
117				entry_buf[len++] = key;
118				putchar(key);
119			}
120		}
121	} while (key != '\r');
122	putchar('\n');
123
124	if (len == 0)
125		return VIDEO_CURRENT_MODE; /* Default */
126
127	v = 0;
128	for (i = 0; i < len; i++) {
129		v <<= 4;
130		key = entry_buf[i] | 0x20;
131		v += (key > '9') ? key-'a'+10 : key-'0';
132	}
133
134	return v;
135}
136
137static void display_menu(void)
138{
139	struct card_info *card;
140	struct mode_info *mi;
141	char ch;
142	int i;
143	int nmodes;
144	int modes_per_line;
145	int col;
146
147	nmodes = 0;
148	for (card = video_cards; card < video_cards_end; card++)
149		nmodes += card->nmodes;
150
151	modes_per_line = 1;
152	if (nmodes >= 20)
153		modes_per_line = 3;
154
155	for (col = 0; col < modes_per_line; col++)
156		puts("Mode: Resolution:  Type: ");
157	putchar('\n');
158
159	col = 0;
160	ch = '0';
161	for (card = video_cards; card < video_cards_end; card++) {
162		mi = card->modes;
163		for (i = 0; i < card->nmodes; i++, mi++) {
164			char resbuf[32];
165			int visible = mi->x && mi->y;
166			u16 mode_id = mi->mode ? mi->mode :
167				(mi->y << 8)+mi->x;
168
169			if (!visible)
170				continue; /* Hidden mode */
171
172			if (mi->depth)
173				sprintf(resbuf, "%dx%d", mi->y, mi->depth);
174			else
175				sprintf(resbuf, "%d", mi->y);
176
177			printf("%c %03X %4dx%-7s %-6s",
178			       ch, mode_id, mi->x, resbuf, card->card_name);
179			col++;
180			if (col >= modes_per_line) {
181				putchar('\n');
182				col = 0;
183			}
184
185			if (ch == '9')
186				ch = 'a';
187			else if (ch == 'z' || ch == ' ')
188				ch = ' '; /* Out of keys... */
189			else
190				ch++;
191		}
192	}
193	if (col)
194		putchar('\n');
195}
196
197#define H(x)	((x)-'a'+10)
198#define SCAN	((H('s')<<12)+(H('c')<<8)+(H('a')<<4)+H('n'))
199
200static unsigned int mode_menu(void)
201{
202	int key;
203	unsigned int sel;
204
205	puts("Press <ENTER> to see video modes available, "
206	     "<SPACE> to continue, or wait 30 sec\n");
207
208	kbd_flush();
209	while (1) {
210		key = getchar_timeout();
211		if (key == ' ' || key == 0)
212			return VIDEO_CURRENT_MODE; /* Default */
213		if (key == '\r')
214			break;
215		putchar('\a');	/* Beep! */
216	}
217
218
219	for (;;) {
220		display_menu();
221
222		puts("Enter a video mode or \"scan\" to scan for "
223		     "additional modes: ");
224		sel = get_entry();
225		if (sel != SCAN)
226			return sel;
227
228		probe_cards(1);
229	}
230}
231
232/* Save screen content to the heap */
233static struct saved_screen {
234	int x, y;
235	int curx, cury;
236	u16 *data;
237} saved;
238
239static void save_screen(void)
240{
241	/* Should be called after store_mode_params() */
242	saved.x = boot_params.screen_info.orig_video_cols;
243	saved.y = boot_params.screen_info.orig_video_lines;
244	saved.curx = boot_params.screen_info.orig_x;
245	saved.cury = boot_params.screen_info.orig_y;
246
247	if (!heap_free(saved.x*saved.y*sizeof(u16)+512))
248		return;		/* Not enough heap to save the screen */
249
250	saved.data = GET_HEAP(u16, saved.x*saved.y);
251
252	set_fs(video_segment);
253	copy_from_fs(saved.data, 0, saved.x*saved.y*sizeof(u16));
254}
255
256static void restore_screen(void)
257{
258	/* Should be called after store_mode_params() */
259	int xs = boot_params.screen_info.orig_video_cols;
260	int ys = boot_params.screen_info.orig_video_lines;
261	int y;
262	addr_t dst = 0;
263	u16 *src = saved.data;
264	struct biosregs ireg;
265
266	if (graphic_mode)
267		return;		/* Can't restore onto a graphic mode */
268
269	if (!src)
270		return;		/* No saved screen contents */
271
272	/* Restore screen contents */
273
274	set_fs(video_segment);
275	for (y = 0; y < ys; y++) {
276		int npad;
277
278		if (y < saved.y) {
279			int copy = (xs < saved.x) ? xs : saved.x;
280			copy_to_fs(dst, src, copy*sizeof(u16));
281			dst += copy*sizeof(u16);
282			src += saved.x;
283			npad = (xs < saved.x) ? 0 : xs-saved.x;
284		} else {
285			npad = xs;
286		}
287
288		/* Writes "npad" blank characters to
289		   video_segment:dst and advances dst */
290		asm volatile("pushw %%es ; "
291			     "movw %2,%%es ; "
292			     "shrw %%cx ; "
293			     "jnc 1f ; "
294			     "stosw \n\t"
295			     "1: rep;stosl ; "
296			     "popw %%es"
297			     : "+D" (dst), "+c" (npad)
298			     : "bdS" (video_segment),
299			       "a" (0x07200720));
300	}
301
302	/* Restore cursor position */
303	if (saved.curx >= xs)
304		saved.curx = xs-1;
305	if (saved.cury >= ys)
306		saved.cury = ys-1;
307
308	initregs(&ireg);
309	ireg.ah = 0x02;		/* Set cursor position */
310	ireg.dh = saved.cury;
311	ireg.dl = saved.curx;
312	intcall(0x10, &ireg, NULL);
313
314	store_cursor_position();
315}
316
317void set_video(void)
318{
319	u16 mode = boot_params.hdr.vid_mode;
320
321	RESET_HEAP();
322
323	store_mode_params();
324	save_screen();
325	probe_cards(0);
326
327	for (;;) {
328		if (mode == ASK_VGA)
329			mode = mode_menu();
330
331		if (!set_mode(mode))
332			break;
333
334		printf("Undefined video mode number: %x\n", mode);
335		mode = ASK_VGA;
336	}
337	boot_params.hdr.vid_mode = mode;
338	vesa_store_edid();
339	store_mode_params();
340
341	if (do_restore)
342		restore_screen();
343}
344