/* -*- linux-c -*- ------------------------------------------------------- *
   *
   *   Copyright (C) 1991, 1992 Linus Torvalds
   *   Copyright 2007 rPath, Inc. - All Rights Reserved
   *   Copyright 2009 Intel Corporation; author H. Peter Anvin
   *
   *   This file is part of the Linux kernel, and is made available under
   *   the terms of the GNU General Public License version 2.
   *
   * ----------------------------------------------------------------------- */
  
  /*
   * Common all-VGA modes
   */
  
  #include "boot.h"
  #include "video.h"
  
  static struct mode_info vga_modes[] = {
  	{ VIDEO_80x25,  80, 25, 0 },
  	{ VIDEO_8POINT, 80, 50, 0 },
  	{ VIDEO_80x43,  80, 43, 0 },
  	{ VIDEO_80x28,  80, 28, 0 },
  	{ VIDEO_80x30,  80, 30, 0 },
  	{ VIDEO_80x34,  80, 34, 0 },
  	{ VIDEO_80x60,  80, 60, 0 },
  };
  
  static struct mode_info ega_modes[] = {
  	{ VIDEO_80x25,  80, 25, 0 },
  	{ VIDEO_8POINT, 80, 43, 0 },
  };
  
  static struct mode_info cga_modes[] = {
  	{ VIDEO_80x25,  80, 25, 0 },
  };
  
  static __videocard video_vga;
  
  /* Set basic 80x25 mode */
  static u8 vga_set_basic_mode(void)
  {
  	struct biosregs ireg, oreg;
  	u8 mode;
  
  	initregs(&ireg);
  
  	/* Query current mode */
  	ireg.ax = 0x0f00;
  	intcall(0x10, &ireg, &oreg);
  	mode = oreg.al;
  
  	if (mode != 3 && mode != 7)
  		mode = 3;
  
  	/* Set the mode */
  	ireg.ax = mode;		/* AH=0: set mode */
  	intcall(0x10, &ireg, NULL);
  	do_restore = 1;
  	return mode;
  }
  
  static void vga_set_8font(void)
  {
  	/* Set 8x8 font - 80x43 on EGA, 80x50 on VGA */
  	struct biosregs ireg;
  
  	initregs(&ireg);
  
  	/* Set 8x8 font */
  	ireg.ax = 0x1112;
  	/* ireg.bl = 0; */
  	intcall(0x10, &ireg, NULL);
  
  	/* Use alternate print screen */
  	ireg.ax = 0x1200;
  	ireg.bl = 0x20;
  	intcall(0x10, &ireg, NULL);
  
  	/* Turn off cursor emulation */
  	ireg.ax = 0x1201;
  	ireg.bl = 0x34;
  	intcall(0x10, &ireg, NULL);
  
  	/* Cursor is scan lines 6-7 */
  	ireg.ax = 0x0100;
  	ireg.cx = 0x0607;
  	intcall(0x10, &ireg, NULL);
  }
  
  static void vga_set_14font(void)
  {
  	/* Set 9x14 font - 80x28 on VGA */
  	struct biosregs ireg;
  
  	initregs(&ireg);
  
  	/* Set 9x14 font */
  	ireg.ax = 0x1111;
  	/* ireg.bl = 0; */
  	intcall(0x10, &ireg, NULL);
  
  	/* Turn off cursor emulation */
  	ireg.ax = 0x1201;
  	ireg.bl = 0x34;
  	intcall(0x10, &ireg, NULL);
  
  	/* Cursor is scan lines 11-12 */
  	ireg.ax = 0x0100;
  	ireg.cx = 0x0b0c;
  	intcall(0x10, &ireg, NULL);
  }
  
  static void vga_set_80x43(void)
  {
  	/* Set 80x43 mode on VGA (not EGA) */
  	struct biosregs ireg;
  
  	initregs(&ireg);
  
  	/* Set 350 scans */
  	ireg.ax = 0x1201;
  	ireg.bl = 0x30;
  	intcall(0x10, &ireg, NULL);
  
  	/* Reset video mode */
  	ireg.ax = 0x0003;
  	intcall(0x10, &ireg, NULL);
  
  	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(void)
  {
  	u16 crtc;		/* CRTC base address */
  	u8  csel;		/* CRTC miscellaneous output register */
  
  	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(0xdf, 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, 0x3c2);
  }
  
  static void vga_set_vertical_end(int lines)
  {
  	u16 crtc;		/* CRTC base address */
  	u8  ovfw;		/* CRTC overflow register */
  	int end = lines-1;
  
  	crtc = vga_crtc();
  
  	ovfw = 0x3c | ((end >> (8-1)) & 0x02) | ((end >> (9-6)) & 0x40);
  
  	out_idx(ovfw, crtc, 0x07); /* Vertical overflow */
  	out_idx(end,  crtc, 0x12); /* Vertical display end */
  }
  
  static void vga_set_80x30(void)
  {
  	vga_set_480_scanlines();
  	vga_set_vertical_end(30*16);
  }
  
  static void vga_set_80x34(void)
  {
  	vga_set_480_scanlines();
  	vga_set_14font();
  	vga_set_vertical_end(34*14);
  }
  
  static void vga_set_80x60(void)
  {
  	vga_set_480_scanlines();
  	vga_set_8font();
  	vga_set_vertical_end(60*8);
  }
  
  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),
  	};
  
  	struct biosregs ireg, oreg;
  
  	initregs(&ireg);
  
  	ireg.ax = 0x1200;
  	ireg.bl = 0x10;		/* Check EGA/VGA */
  	intcall(0x10, &ireg, &oreg);
  
  #ifndef _WAKEUP
  	boot_params.screen_info.orig_video_ega_bx = oreg.bx;
  #endif
  
  	/* If we have MDA/CGA/HGC then BL will be unchanged at 0x10 */
  	if (oreg.bl != 0x10) {
  		/* EGA/VGA */
  		ireg.ax = 0x1a00;
  		intcall(0x10, &ireg, &oreg);
  
  		if (oreg.al == 0x1a) {
  			adapter = ADAPTER_VGA;
  #ifndef _WAKEUP
  			boot_params.screen_info.orig_video_isVGA = 1;
  #endif
  		} 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];
  }
  
  static __videocard video_vga = {
  	.card_name	= "VGA",
  	.probe		= vga_probe,
  	.set_mode	= vga_set_mode,
  };