Video mode probing support for the new x86 setup code

Video mode probing for the new x86 setup code.  This code breaks down
different drivers into modules.  This code deliberately drops support
for a lot of the vendor-specific mode probing present in the assembly
version, since a lot of those probes have been found to be stale in
current versions of those chips -- frequently, support for those modes
have been dropped from recent video BIOSes due to space constraints,
but the video BIOS signatures are still the same.

However, additional drivers should be extremely straightforward to plug
in, if desirable.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 260 insertions, 0 deletions

diff --git a/arch/i386/boot/video-vga.c b/arch/i386/boot/video-vga.c
new file mode 100644
index 000000000000..700d09a9c9b3
--- /dev/null
+++ b/arch/i386/boot/video-vga.c
@@ -0,0 +1,260 @@
+/* -*- 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-vga.c
+ *
+ * Common all-VGA modes
+ */
+
+#include "boot.h"
+#include "video.h"
+
+static struct mode_info vga_modes[] = {
+	{ VIDEO_80x25,  80, 25 },
+	{ VIDEO_8POINT, 80, 50 },
+	{ VIDEO_80x43,  80, 43 },
+	{ VIDEO_80x28,  80, 28 },
+	{ VIDEO_80x30,  80, 30 },
+	{ VIDEO_80x34,  80, 34 },
+	{ VIDEO_80x60,  80, 60 },
+};
+
+static struct mode_info ega_modes[] = {
+	{ VIDEO_80x25,  80, 25 },
+	{ VIDEO_8POINT, 80, 43 },
+};
+
+static struct mode_info cga_modes[] = {
+	{ VIDEO_80x25,  80, 25 },
+};
+
+__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(INT10
+		    : : "a" (0x1202), "b" (0x0030)
+		    : "ecx", "edx", "esi", "edi");
+	}
+#endif
+
+	ax = 0x0f00;
+	asm(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 */
+	asm volatile(INT10
+		     : : "a" (mode)
+		     : "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 end)
+{
+	u16 crtc;
+	u8  csel;
+
+	crtc = vga_crtc();
+
+	out_idx(0x0c, crtc, 0x11); /* Vertical sync end, unlock CR0-7 */
+	out_idx(0x0b, crtc, 0x06); /* Vertical total */
+	out_idx(0x3e, 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, 0x3cc);
+}
+
+static void vga_set_80x30(void)
+{
+	vga_set_480_scanlines(0xdf);
+}
+
+static void vga_set_80x34(void)
+{
+	vga_set_14font();
+	vga_set_480_scanlines(0xdb);
+}
+
+static void vga_set_80x60(void)
+{
+	vga_set_8font();
+	vga_set_480_scanlines(0xdf);
+}
+
+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)
+{
+	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" (boot_params.screen_info.orig_video_ega_bx)
+	    : "a" (0x1200), "b" (0x10) /* Check EGA/VGA */
+	    : "ecx", "edx", "esi", "edi");
+
+	/* If we have MDA/CGA/HGC then BL will be unchanged at 0x10 */
+	if ((u8)boot_params.screen_info.orig_video_ega_bx != 0x10) {
+		/* EGA/VGA */
+		asm(INT10
+		    : "=a" (vga_flag)
+		    : "a" (0x1a00)
+		    : "ebx", "ecx", "edx", "esi", "edi");
+
+		if (vga_flag == 0x1a) {
+			adapter = ADAPTER_VGA;
+			boot_params.screen_info.orig_video_isVGA = 1;
+		} 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];
+}
+
+__videocard video_vga =
+{
+	.card_name	= "VGA",
+	.probe		= vga_probe,
+	.set_mode	= vga_set_mode,
+};