/* -*- 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.
*
* ----------------------------------------------------------------------- */
/*
* arch/i386/boot/video.c
*
* Select video mode
*/
#include "boot.h"
#include "video.h"
#include "vesa.h"
/*
* Mode list variables
*/
static struct card_info cards[]; /* List of cards to probe for */
/*
* Common variables
*/
int adapter; /* 0=CGA/MDA/HGC, 1=EGA, 2=VGA+ */
u16 video_segment;
int force_x, force_y; /* Don't query the BIOS for cols/rows */
int do_restore = 0; /* Screen contents changed during mode flip */
int graphic_mode; /* Graphic mode with linear frame buffer */
static void store_cursor_position(void)
{
u16 curpos;
u16 ax, bx;
ax = 0x0300;
bx = 0;
asm(INT10
: "=d" (curpos), "+a" (ax), "+b" (bx)
: : "ecx", "esi", "edi");
boot_params.screen_info.orig_x = curpos;
boot_params.screen_info.orig_y = curpos >> 8;
}
static void store_video_mode(void)
{
u16 ax, page;
/* N.B.: the saving of the video page here is a bit silly,
since we pretty much assume page 0 everywhere. */
ax = 0x0f00;
asm(INT10
: "+a" (ax), "=b" (page)
: : "ecx", "edx", "esi", "edi");
/* Not all BIOSes are clean with respect to the top bit */
boot_params.screen_info.orig_video_mode = ax & 0x7f;
boot_params.screen_info.orig_video_page = page >> 8;
}
/*
* 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;
}
/* Probe the video drivers and have them generate their mode lists. */
static void probe_cards(int unsafe)
{
struct card_info *card;
static u8 probed[2];
if (probed[unsafe])
return;
probed[unsafe] = 1;
for (card = video_cards; card < video_cards_end; card++) {
if (card->unsafe == unsafe) {
if (card->probe)
card->nmodes = card->probe();
else
card->nmodes = 0;
}
}
}
/* Test if a mode is defined */
int mode_defined(u16 mode)
{
struct card_info *card;
struct mode_info *mi;
int i;
for (card = video_cards; card < video_cards_end; card++) {
mi = card->modes;
for (i = 0; i < card->nmodes; i++, mi++) {
if (mi->mode == mode)
return 1;
}
}
return 0;
}
/* Set mode (without recalc) */
static int raw_set_mode(u16 mode, u16 *real_mode)
{
int nmode, i;
struct card_info *card;
struct mode_info *mi;
/* Drop the recalc bit if set */
mode &= ~VIDEO_RECALC;
/* Scan for mode based on fixed ID, position, or resolution */
nmode = 0;
for (card = video_cards; card < video_cards_end; card++) {
mi = card->modes;
for (i = 0; i < card->nmodes; i++, mi++) {
int visible = mi->x || mi->y;
if ((mode == nmode && visible) ||
mode == mi->mode ||
mode == (mi->y << 8)+mi->x) {
*real_mode = mi->mode;
return card->set_mode(mi);
}
if (visible)
nmode++;
}
}
/* Nothing found? Is it an "exceptional" (unprobed) mode? */
for (card = video_cards; card < video_cards_end; card++) {
if (mode >= card->xmode_first &&
mode < card->xmode_first+card->xmode_n) {
struct mode_info mix;
*real_mode = mix.mode = mode;
mix.x = mix.y = 0;
return card->set_mode(&mix);
}
}
/* Otherwise, failure... */
return -1;
}
/*
* Recalculate the vertical video cutoff (hack!)
*/
static void vga_recalc_vertical(void)
{
unsigned int font_size, rows;
u16 crtc;
u8 pt, ov;
set_fs(0);
font_size = rdfs8(0x485); /* BIOS: font size (pixels) */
rows = force_y ? force_y : rdfs8(0x484)+1; /* Text rows */
rows *= font_size; /* Visible scan lines */
rows--; /* ... minus one */
crtc = vga_crtc();
pt = in_idx(crtc, 0x11);
pt &= ~0x80; /* Unlock CR0-7 */
out_idx(pt, crtc, 0x11);
out_idx((u8)rows, crtc, 0x12); /* Lower height register */
ov = in_idx(crtc, 0x07); /* Overflow register */
ov &= 0xbd;
ov |= (rows >> (8-1)) & 0x02;
ov |= (rows >> (9-6)) & 0x40;
out_idx(ov, crtc, 0x07);
}
/* Set mode (with recalc if specified) */
static int set_mode(u16 mode)
{
int rv;
u16 real_mode;
/* Very special mode numbers... */
if (mode == VIDEO_CURRENT_MODE)
return 0; /* Nothing to do... */
else if (mode == NORMAL_VGA)
mode = VIDEO_80x25;
else if (mode == EXTENDED_VGA)
mode = VIDEO_8POINT;
rv = raw_set_mode(mode, &real_mode);
if (rv)
return rv;
if (mode & VIDEO_RECALC)
vga_recalc_vertical();
/* Save the canonical mode number for the kernel, not
an alias, size specification or menu position */
boot_params.hdr.vid_mode = real_mode;
return 0;
}
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;
puts("Mode: COLSxROWS:\n");
ch = '0';
for (card = video_cards; card < video_cards_end; card++) {
mi = card->modes;
for (i = 0; i < card->nmodes; i++, mi++) {
int visible = mi->x && mi->y;
u16 mode_id = mi->mode ? mi->mode :
(mi->y << 8)+mi->x;
if (!visible)
continue; /* Hidden mode */
printf("%c %04X %3dx%-3d %s\n",
ch, mode_id, mi->x, mi->y, card->card_name);
if (ch == '9')
ch = 'a';
else if (ch == 'z' || ch == ' ')
ch = ' '; /* Out of keys... */
else
ch++;
}
}
}
#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);
}
}
#ifdef CONFIG_VIDEO_RETAIN
/* Save screen content to the heap */
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;
u16 ax, bx, dx;
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 */
ax = 0x0200; /* Set cursor position */
bx = 0; /* Page number (<< 8) */
dx = (saved.cury << 8)+saved.curx;
asm volatile(INT10
: "+a" (ax), "+b" (bx), "+d" (dx)
: : "ecx", "esi", "edi");
}
#else
#define save_screen() ((void)0)
#define restore_screen() ((void)0)
#endif
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;
}
vesa_store_edid();
store_mode_params();
if (do_restore)
restore_screen();
}
