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-rw-r--r--arch/x86/boot/video-mode.c171
1 files changed, 171 insertions, 0 deletions
diff --git a/arch/x86/boot/video-mode.c b/arch/x86/boot/video-mode.c
new file mode 100644
index 000000000..9ada55dc1
--- /dev/null
+++ b/arch/x86/boot/video-mode.c
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ * Copyright 2007-2008 rPath, Inc. - All Rights Reserved
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * arch/i386/boot/video-mode.c
+ *
+ * Set the video mode. This is separated out into a different
+ * file in order to be shared with the ACPI wakeup code.
+ */
+
+#include "boot.h"
+#include "video.h"
+#include "vesa.h"
+
+#include <uapi/asm/boot.h>
+
+/*
+ * Common variables
+ */
+int adapter; /* 0=CGA/MDA/HGC, 1=EGA, 2=VGA+ */
+int force_x, force_y; /* Don't query the BIOS for cols/rows */
+int do_restore; /* Screen contents changed during mode flip */
+int graphic_mode; /* Graphic mode with linear frame buffer */
+
+/* Probe the video drivers and have them generate their mode lists. */
+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) */
+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 */
+#ifndef _WAKEUP
+ boot_params.hdr.vid_mode = real_mode;
+#endif
+ return 0;
+}