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TOMOYO Linux Cross Reference
Linux/arch/x86/boot/video.c

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  1 /* -*- linux-c -*- ------------------------------------------------------- *
  2  *
  3  *   Copyright (C) 1991, 1992 Linus Torvalds
  4  *   Copyright 2007 rPath, Inc. - All Rights Reserved
  5  *   Copyright 2009 Intel Corporation; author H. Peter Anvin
  6  *
  7  *   This file is part of the Linux kernel, and is made available under
  8  *   the terms of the GNU General Public License version 2.
  9  *
 10  * ----------------------------------------------------------------------- */
 11 
 12 /*
 13  * Select video mode
 14  */
 15 
 16 #include <uapi/asm/boot.h>
 17 
 18 #include "boot.h"
 19 #include "video.h"
 20 #include "vesa.h"
 21 
 22 static u16 video_segment;
 23 
 24 static void store_cursor_position(void)
 25 {
 26         struct biosregs ireg, oreg;
 27 
 28         initregs(&ireg);
 29         ireg.ah = 0x03;
 30         intcall(0x10, &ireg, &oreg);
 31 
 32         boot_params.screen_info.orig_x = oreg.dl;
 33         boot_params.screen_info.orig_y = oreg.dh;
 34 
 35         if (oreg.ch & 0x20)
 36                 boot_params.screen_info.flags |= VIDEO_FLAGS_NOCURSOR;
 37 
 38         if ((oreg.ch & 0x1f) > (oreg.cl & 0x1f))
 39                 boot_params.screen_info.flags |= VIDEO_FLAGS_NOCURSOR;
 40 }
 41 
 42 static void store_video_mode(void)
 43 {
 44         struct biosregs ireg, oreg;
 45 
 46         /* N.B.: the saving of the video page here is a bit silly,
 47            since we pretty much assume page 0 everywhere. */
 48         initregs(&ireg);
 49         ireg.ah = 0x0f;
 50         intcall(0x10, &ireg, &oreg);
 51 
 52         /* Not all BIOSes are clean with respect to the top bit */
 53         boot_params.screen_info.orig_video_mode = oreg.al & 0x7f;
 54         boot_params.screen_info.orig_video_page = oreg.bh;
 55 }
 56 
 57 /*
 58  * Store the video mode parameters for later usage by the kernel.
 59  * This is done by asking the BIOS except for the rows/columns
 60  * parameters in the default 80x25 mode -- these are set directly,
 61  * because some very obscure BIOSes supply insane values.
 62  */
 63 static void store_mode_params(void)
 64 {
 65         u16 font_size;
 66         int x, y;
 67 
 68         /* For graphics mode, it is up to the mode-setting driver
 69            (currently only video-vesa.c) to store the parameters */
 70         if (graphic_mode)
 71                 return;
 72 
 73         store_cursor_position();
 74         store_video_mode();
 75 
 76         if (boot_params.screen_info.orig_video_mode == 0x07) {
 77                 /* MDA, HGC, or VGA in monochrome mode */
 78                 video_segment = 0xb000;
 79         } else {
 80                 /* CGA, EGA, VGA and so forth */
 81                 video_segment = 0xb800;
 82         }
 83 
 84         set_fs(0);
 85         font_size = rdfs16(0x485); /* Font size, BIOS area */
 86         boot_params.screen_info.orig_video_points = font_size;
 87 
 88         x = rdfs16(0x44a);
 89         y = (adapter == ADAPTER_CGA) ? 25 : rdfs8(0x484)+1;
 90 
 91         if (force_x)
 92                 x = force_x;
 93         if (force_y)
 94                 y = force_y;
 95 
 96         boot_params.screen_info.orig_video_cols  = x;
 97         boot_params.screen_info.orig_video_lines = y;
 98 }
 99 
100 static unsigned int get_entry(void)
101 {
102         char entry_buf[4];
103         int i, len = 0;
104         int key;
105         unsigned int v;
106 
107         do {
108                 key = getchar();
109 
110                 if (key == '\b') {
111                         if (len > 0) {
112                                 puts("\b \b");
113                                 len--;
114                         }
115                 } else if ((key >= '' && key <= '9') ||
116                            (key >= 'A' && key <= 'Z') ||
117                            (key >= 'a' && key <= 'z')) {
118                         if (len < sizeof entry_buf) {
119                                 entry_buf[len++] = key;
120                                 putchar(key);
121                         }
122                 }
123         } while (key != '\r');
124         putchar('\n');
125 
126         if (len == 0)
127                 return VIDEO_CURRENT_MODE; /* Default */
128 
129         v = 0;
130         for (i = 0; i < len; i++) {
131                 v <<= 4;
132                 key = entry_buf[i] | 0x20;
133                 v += (key > '9') ? key-'a'+10 : key-'';
134         }
135 
136         return v;
137 }
138 
139 static void display_menu(void)
140 {
141         struct card_info *card;
142         struct mode_info *mi;
143         char ch;
144         int i;
145         int nmodes;
146         int modes_per_line;
147         int col;
148 
149         nmodes = 0;
150         for (card = video_cards; card < video_cards_end; card++)
151                 nmodes += card->nmodes;
152 
153         modes_per_line = 1;
154         if (nmodes >= 20)
155                 modes_per_line = 3;
156 
157         for (col = 0; col < modes_per_line; col++)
158                 puts("Mode: Resolution:  Type: ");
159         putchar('\n');
160 
161         col = 0;
162         ch = '';
163         for (card = video_cards; card < video_cards_end; card++) {
164                 mi = card->modes;
165                 for (i = 0; i < card->nmodes; i++, mi++) {
166                         char resbuf[32];
167                         int visible = mi->x && mi->y;
168                         u16 mode_id = mi->mode ? mi->mode :
169                                 (mi->y << 8)+mi->x;
170 
171                         if (!visible)
172                                 continue; /* Hidden mode */
173 
174                         if (mi->depth)
175                                 sprintf(resbuf, "%dx%d", mi->y, mi->depth);
176                         else
177                                 sprintf(resbuf, "%d", mi->y);
178 
179                         printf("%c %03X %4dx%-7s %-6s",
180                                ch, mode_id, mi->x, resbuf, card->card_name);
181                         col++;
182                         if (col >= modes_per_line) {
183                                 putchar('\n');
184                                 col = 0;
185                         }
186 
187                         if (ch == '9')
188                                 ch = 'a';
189                         else if (ch == 'z' || ch == ' ')
190                                 ch = ' '; /* Out of keys... */
191                         else
192                                 ch++;
193                 }
194         }
195         if (col)
196                 putchar('\n');
197 }
198 
199 #define H(x)    ((x)-'a'+10)
200 #define SCAN    ((H('s')<<12)+(H('c')<<8)+(H('a')<<4)+H('n'))
201 
202 static unsigned int mode_menu(void)
203 {
204         int key;
205         unsigned int sel;
206 
207         puts("Press <ENTER> to see video modes available, "
208              "<SPACE> to continue, or wait 30 sec\n");
209 
210         kbd_flush();
211         while (1) {
212                 key = getchar_timeout();
213                 if (key == ' ' || key == 0)
214                         return VIDEO_CURRENT_MODE; /* Default */
215                 if (key == '\r')
216                         break;
217                 putchar('\a');  /* Beep! */
218         }
219 
220 
221         for (;;) {
222                 display_menu();
223 
224                 puts("Enter a video mode or \"scan\" to scan for "
225                      "additional modes: ");
226                 sel = get_entry();
227                 if (sel != SCAN)
228                         return sel;
229 
230                 probe_cards(1);
231         }
232 }
233 
234 /* Save screen content to the heap */
235 static struct saved_screen {
236         int x, y;
237         int curx, cury;
238         u16 *data;
239 } saved;
240 
241 static void save_screen(void)
242 {
243         /* Should be called after store_mode_params() */
244         saved.x = boot_params.screen_info.orig_video_cols;
245         saved.y = boot_params.screen_info.orig_video_lines;
246         saved.curx = boot_params.screen_info.orig_x;
247         saved.cury = boot_params.screen_info.orig_y;
248 
249         if (!heap_free(saved.x*saved.y*sizeof(u16)+512))
250                 return;         /* Not enough heap to save the screen */
251 
252         saved.data = GET_HEAP(u16, saved.x*saved.y);
253 
254         set_fs(video_segment);
255         copy_from_fs(saved.data, 0, saved.x*saved.y*sizeof(u16));
256 }
257 
258 static void restore_screen(void)
259 {
260         /* Should be called after store_mode_params() */
261         int xs = boot_params.screen_info.orig_video_cols;
262         int ys = boot_params.screen_info.orig_video_lines;
263         int y;
264         addr_t dst = 0;
265         u16 *src = saved.data;
266         struct biosregs ireg;
267 
268         if (graphic_mode)
269                 return;         /* Can't restore onto a graphic mode */
270 
271         if (!src)
272                 return;         /* No saved screen contents */
273 
274         /* Restore screen contents */
275 
276         set_fs(video_segment);
277         for (y = 0; y < ys; y++) {
278                 int npad;
279 
280                 if (y < saved.y) {
281                         int copy = (xs < saved.x) ? xs : saved.x;
282                         copy_to_fs(dst, src, copy*sizeof(u16));
283                         dst += copy*sizeof(u16);
284                         src += saved.x;
285                         npad = (xs < saved.x) ? 0 : xs-saved.x;
286                 } else {
287                         npad = xs;
288                 }
289 
290                 /* Writes "npad" blank characters to
291                    video_segment:dst and advances dst */
292                 asm volatile("pushw %%es ; "
293                              "movw %2,%%es ; "
294                              "shrw %%cx ; "
295                              "jnc 1f ; "
296                              "stosw \n\t"
297                              "1: rep;stosl ; "
298                              "popw %%es"
299                              : "+D" (dst), "+c" (npad)
300                              : "bdS" (video_segment),
301                                "a" (0x07200720));
302         }
303 
304         /* Restore cursor position */
305         if (saved.curx >= xs)
306                 saved.curx = xs-1;
307         if (saved.cury >= ys)
308                 saved.cury = ys-1;
309 
310         initregs(&ireg);
311         ireg.ah = 0x02;         /* Set cursor position */
312         ireg.dh = saved.cury;
313         ireg.dl = saved.curx;
314         intcall(0x10, &ireg, NULL);
315 
316         store_cursor_position();
317 }
318 
319 void set_video(void)
320 {
321         u16 mode = boot_params.hdr.vid_mode;
322 
323         RESET_HEAP();
324 
325         store_mode_params();
326         save_screen();
327         probe_cards(0);
328 
329         for (;;) {
330                 if (mode == ASK_VGA)
331                         mode = mode_menu();
332 
333                 if (!set_mode(mode))
334                         break;
335 
336                 printf("Undefined video mode number: %x\n", mode);
337                 mode = ASK_VGA;
338         }
339         boot_params.hdr.vid_mode = mode;
340         vesa_store_edid();
341         store_mode_params();
342 
343         if (do_restore)
344                 restore_screen();
345 }
346 

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