path: root/src/gfx/vga_gu1.c

/* $XFree86$ */
/*
 * $Workfile: vga_gu1.c $
 *
 * This file contains routines to set modes using the VGA registers.  
 * Since this file is for the first generation graphics unit, it interfaces
 * to SoftVGA registers.  It works for both VSA1 and VSA2.
 *
 * NSC_LIC_ALTERNATIVE_PREAMBLE
 *
 * Revision 1.0
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 * National Semiconductor Alternative GPL-BSD License
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 * National Semiconductor Corporation licenses this software 
 * ("Software"):
 *
 *      Durango
 *
 * under one of the two following licenses, depending on how the 
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/* NSC_LIC_BSD
 *
 * National Semiconductor Corporation Open Source License for Durango
 *
 * (BSD License with Export Notice)
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 * Copyright (c) 1999-2001
 * National Semiconductor Corporation.
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 * END_NSC_LIC_BSD */

/* NSC_LIC_GPL
 *
 * National Semiconductor Corporation Gnu General Public License for Durango
 *
 * (GPL License with Export Notice)
 *
 * Copyright (c) 1999-2001
 * National Semiconductor Corporation.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted under the terms of the GNU General 
 * Public License as published by the Free Software Foundation; either 
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 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 
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 * NATIONAL SEMICONDUCTOR CORPORATION OR CONTRIBUTORS BE LIABLE FOR ANY 
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER 
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE, 
 * INTELLECTUAL PROPERTY INFRINGEMENT, OR OTHERWISE) ARISING IN ANY WAY 
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
 * OF SUCH DAMAGE. See the GNU General Public License for more details. 
 *
 * EXPORT LAWS: THIS LICENSE ADDS NO RESTRICTIONS TO THE EXPORT LAWS OF 
 * YOUR JURISDICTION. It is licensee's responsibility to comply with 
 * any export regulations applicable in licensee's jurisdiction. Under 
 * CURRENT (2001) U.S. export regulations this software 
 * is eligible for export from the U.S. and can be downloaded by or 
 * otherwise exported or reexported worldwide EXCEPT to U.S. embargoed 
 * destinations which include Cuba, Iraq, Libya, North Korea, Iran, 
 * Syria, Sudan, Afghanistan and any other country to which the U.S. 
 * has embargoed goods and services. 
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 * You should have received a copy of the GNU General Public License 
 * along with this file; if not, write to the Free Software Foundation, 
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 * END_NSC_LIC_GPL */

/* SoftVGA Extended CRTC register indices and bit definitions */

#define CRTC_EXTENDED_REGISTER_LOCK		0x30
#define CRTC_MODE_SWITCH_CONTROL		0x3F

/* BIT DEFINITIONS */

#define CRTC_BIT_16BPP					0x01
#define CRTC_BIT_555					0x02

/* LOCAL ROUTINE DEFINITIONS */

int gu1_detect_vsa2(void);

/*---------------------------------*/
/*  MODE TABLES FOR VGA REGISTERS  */
/*---------------------------------*/

/* FOR SoftVGA, the CRTC_EXTENDED_ADDRESS_CONTROL (0x43) is always equal to 
 * 0x03 for a packed linear frame buffer organization.  The 
 * CRTC_EXTENDED_DAC_CONTROL (0x4B) is always equal to 0x03 to work with 
 * older versions of VSA1 (that needed to specify 8 or 16 bit bus to an
 * external RAMDAC.  This is not used in VSA2.  The clock frequency is 
 * specified in register 0x4D if clock control (0x4C) is set to 0x80.
 * Higher resolutions (1280x1024) use the CRTC_EXTENDED_VERTICAL_TIMING
 * register (index 0x41).
 */

gfx_vga_struct gfx_vga_modes[] = {
/*------------------------------------------------------------------------------*/
   {640, 480, 60,			/* 640x480 */
    25,					/* 25 MHz clock = 60 Hz refresh rate */
    0xE3,				/* miscOutput register */
    {0x5F, 0x4F, 0x50, 0x82, 0x54, 0x80, 0x0B, 0x3E,	/* standard CRTC */
     0x80, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0xEA, 0x0C, 0xDF, 0x50, 0x00, 0xE7, 0x04, 0xE3, 0xFF},
    {0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00,	/* extended CRTC */
     0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00}},
/*------------------------------------------------------------------------------*/
   {640, 480, 72,			/* 640x480 */
    29,					/* 29 MHz clock = 72 Hz refresh rate */
    0xE3,				/* miscOutput register */
    {0x63, 0x4f, 0x50, 0x86, 0x55, 0x99, 0x06, 0x3e,	/* standard CRTC */
     0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0xe9, 0x0c, 0xdf, 0x00, 0x00, 0xe7, 0x00, 0xe3, 0xff},
    {0x6D, 0x00, 0x00, 0x03, 0x00, 0x01, 0x01, 0x00,	/* extended CRTC */
     0x00, 0x00, 0x01, 0x08, 0x80, 0x1F, 0x00, 0x4B}},
/*------------------------------------------------------------------------------*/
   {640, 480, 75,			/* 640x480 */
    31,					/* 31.5 MHz clock = 75 Hz refresh rate */
    0xE3,				/* miscOutput register */
    {0x64, 0x4F, 0x4F, 0x88, 0x54, 0x9B, 0xF2, 0x1F,	/* standard CRTC */
     0x80, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0xE1, 0x04, 0xDF, 0x50, 0x00, 0xDF, 0xF3, 0xE3, 0xFF},
    {0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00,	/* extended CRTC */
     0x00, 0x00, 0x00, 0x03, 0x80, 0x1F, 0x00, 0x00}},
/*------------------------------------------------------------------------------*/
   {800, 600, 60,			/* 800x600 */
    40,					/* 40 MHz clock = 60 Hz refresh rate */
    0x23,				/* miscOutput register */
    {0x7F, 0x63, 0x64, 0x82, 0x6B, 0x1B, 0x72, 0xF0,	/* standard CRTC */
     0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0x59, 0x0D, 0x57, 0x64, 0x00, 0x57, 0x73, 0xE3, 0xFF},
    {0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00,	/* extended CRTC */
     0x00, 0x00, 0x00, 0x03, 0x80, 0x28, 0x00, 0x00}},
/*------------------------------------------------------------------------------*/
   {800, 600, 72,			/* 800x600 */
    47,					/* 47 MHz clock = 72 Hz refresh rate */
    0x2B,				/* miscOutput register */
    {0x7D, 0x63, 0x63, 0x81, 0x6D, 0x1B, 0x98, 0xF0,	/* standard CRTC */
     0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0x7D, 0x03, 0x57, 0x00, 0x00, 0x57, 0x9A, 0xE3, 0xFF},
    {0x6F, 0x00, 0x00, 0x03, 0x00, 0x01, 0x01, 0x00,	/* extended CRTC */
     0x00, 0x00, 0x01, 0x08, 0x80, 0x32, 0x00, 0x4B}},
/*------------------------------------------------------------------------------*/
   {800, 600, 75,			/* 800x600 */
    49,					/* 49.5 MHz clock = 75 Hz refresh rate */
    0x23,				/* miscOutput register */
    {0x7F, 0x63, 0x63, 0x83, 0x68, 0x11, 0x6F, 0xF0,	/* standard CRTC */
     0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0x59, 0x1C, 0x57, 0x64, 0x00, 0x57, 0x70, 0xE3, 0xFF},
    {0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00,	/* extended CRTC */
     0x00, 0x00, 0x00, 0x03, 0x80, 0x31, 0x00, 0x00}},
/*------------------------------------------------------------------------------*/
   {1024, 768, 60,			/* 1024x768 */
    65,					/* 65 MHz clock = 60 Hz refresh rate */
    0xE3,				/* miscOutput register */
    {0xA3, 0x7F, 0x80, 0x86, 0x85, 0x96, 0x24, 0xF5,	/* standard CRTC */
     0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0x04, 0x0A, 0xFF, 0x80, 0x00, 0xFF, 0x25, 0xE3, 0xFF},
    {0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00,	/* extended CRTC */
     0x00, 0x00, 0x00, 0x03, 0x80, 0x41, 0x00, 0x00}},
/*------------------------------------------------------------------------------*/
   {1024, 768, 70,			/* 1024x768 */
    76,					/* 76 MHz clock = 70 Hz refresh rate */
    0x2B,				/* miscOutput register */
    {0xA1, 0x7F, 0x7F, 0x85, 0x85, 0x95, 0x24, 0xF5,	/* standard CRTC */
     0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0x03, 0x09, 0xFF, 0x00, 0x00, 0xFF, 0x26, 0xE3, 0xFF},
    {0x62, 0x00, 0x00, 0x03, 0x00, 0x01, 0x01, 0x00,	/* extended CRTC */
     0x00, 0x00, 0x01, 0x02, 0x80, 0x4B, 0x00, 0x4B}},
/*------------------------------------------------------------------------------*/
   {1024, 768, 75,			/* 1024x768 */
    79,					/* 79 MHz clock = 75 Hz refresh rate */
    0xE3,				/* miscOutput register */
    {0x9F, 0x7F, 0x7F, 0x83, 0x84, 0x8F, 0x1E, 0xF5,	/* standard CRTC */
     0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0x01, 0x04, 0xFF, 0x80, 0x00, 0xFF, 0x1F, 0xE3, 0xFF},
    {0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00,	/* extended CRTC */
     0x00, 0x00, 0x00, 0x03, 0x80, 0x4F, 0x00, 0x00}},
/*------------------------------------------------------------------------------*/
   {1280, 1024, 60,			/* 1280x1024 */
    108,				/* 108 MHz clock = 60 Hz refresh rate */
    0x23,				/* miscOutput register */
    {0xCF, 0x9F, 0xA0, 0x92, 0xAA, 0x19, 0x28, 0x52,	/* standard CRTC */
     0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0x01, 0x04, 0xFF, 0xA0, 0x00, 0x00, 0x29, 0xE3, 0xFF},
    {0x00, 0x51, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00,	/* extended CRTC */
     0x00, 0x00, 0x00, 0x03, 0x80, 0x6C, 0x00, 0x00}},
/*------------------------------------------------------------------------------*/
   {1280, 1024, 75,			/* 1280x1024 */
    135,				/* 135 MHz clock = 75 Hz refresh rate */
    0x23,				/* miscOutput register */
    {0xCE, 0x9F, 0x9F, 0x92, 0xA4, 0x15, 0x28, 0x52,	/* standard CRTC */
     0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0x01, 0x04, 0xFF, 0xA0, 0x00, 0x00, 0x29, 0xE3, 0xFF},
    {0x00, 0x51, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00,	/* extended CRTC */
     0x00, 0x00, 0x00, 0x03, 0x80, 0x87, 0x00, 0x00}},
/*------------------------------------------------------------------------------*/
   {1280, 1024, 85,			/* 1280x1024 */
    159,				/* 159 MHz clock = 85 Hz refresh rate */
    0x2B,				/* miscOutput register */
    {0xD3, 0x9F, 0xA0, 0x98, 0xA8, 0x9C, 0x2E, 0x5A,	/* standard CRTC */
     0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0x01, 0x04, 0xFF, 0x00, 0x00, 0xFF, 0x30, 0xE3, 0xFF},
    {0x6B, 0x41, 0x00, 0x03, 0x00, 0x01, 0x00, 0x00,	/* extended CRTC */
     0x00, 0x00, 0x01, 0x00, 0x80, 0x9D, 0x00, 0x4B}},

/*------------------------------------------------------------------------------*/
};

#define GFX_VGA_MODES sizeof(gfx_vga_modes)/sizeof(gfx_vga_struct)

/*-----------------------------------------------------------------------------
 * gfx_get_softvga_active
 *
 * This returns the active status of SoftVGA
 *-----------------------------------------------------------------------------
 */
int
gfx_get_softvga_active(void)
{
   unsigned short crtcindex, crtcdata;

   if (gu1_detect_vsa2())
      return (gfx_get_vsa2_softvga_enable());

   crtcindex = (INB(0x3CC) & 0x01) ? 0x3D4 : 0x3B4;
   crtcdata = crtcindex + 1;

   OUTB(crtcindex, CRTC_MODE_SWITCH_CONTROL);
   return (INB(crtcdata) & 0x1);
}

/*-----------------------------------------------------------------------------
 * gfx_vga_test_pci
 *
 * This routine looks for the VGA PCI header.  It checks to see that bit 1 
 * of the command register is writable to know that SoftVGA is trapping
 * the PCI config cuscles.  If SoftVGA is not emulating the header, the 
 * hardware will still respond with the proper device ID, etc.  
 * 
 * We need to know that SoftVGA is really there so that we can set the 
 * command register and have the proper effect (enable trapping of VGA).  
 * Otherwise, if we enable VGA via the PCI header, trapping really won't be 
 * enabled and the VGA register writes will go out to the external card.
 *-----------------------------------------------------------------------------
 */
int
gfx_vga_test_pci(void)
{
   int softvga = 1;
   unsigned long value;

   value = gfx_pci_config_read(0x80009400);
   if ((value & 0x0000FFFF) != 0x1078)
      softvga = 0;
   else {
      value = gfx_pci_config_read(0x80009404);
      gfx_pci_config_write(0x80009404, value | 0x02);
      if (!(gfx_pci_config_read(0x80009404) & 0x02))
	 softvga = 0;
      gfx_pci_config_write(0x80009404, value);
   }
   return (softvga);
}

/*-----------------------------------------------------------------------------
 * gfx_vga_get_pci_command
 *
 * This routine returns the value of the PCI command register.
 *-----------------------------------------------------------------------------
 */
unsigned char
gfx_vga_get_pci_command(void)
{
   unsigned long value;

   value = gfx_pci_config_read(0x80009404);
   return ((unsigned char)value);
}

/*-----------------------------------------------------------------------------
 * gfx_vga_set_pci_command
 *
 * This routine writes the value of the PCI command register.  It is used 
 * to enable or disable SoftVGA.
 *
 *    Bit 0: Enable VGA IO
 *    Bit 1: Enable VGA memory
 *-----------------------------------------------------------------------------
 */
int
gfx_vga_set_pci_command(unsigned char command)
{
   unsigned long value;

   value = gfx_pci_config_read(0x80009404) & 0xFFFFFF00;
   value |= (unsigned long)command;
   gfx_pci_config_write(0x80009404, value);
   return (GFX_STATUS_OK);
}

/*-----------------------------------------------------------------------------
 * gfx_vga_seq_reset
 *
 * This routine enables or disables SoftVGA.  It is used to make SoftVGA 
 * "be quiet" and not interfere with any of the direct hardware access from 
 * Durango.  For VSA1, the sequencer is reset to stop text redraws.  VSA2 may 
 * provide a better way to have SoftVGA sit in the background.
 *-----------------------------------------------------------------------------
 */
int
gfx_vga_seq_reset(int reset)
{
   OUTB(0x3C4, 0);
   OUTB(0x3C5, (unsigned char)(reset ? 0x00 : 0x03));
   return (GFX_STATUS_OK);
}

/*-----------------------------------------------------------------------------
 * gfx_vga_set_graphics_bits
 *
 * This routine sets the standard VGA sequencer, graphics controller, and
 * attribute registers to appropriate values for a graphics mode (packed, 
 * 8 BPP or greater).  This is also known as "VESA" modes.  The timings for
 * a particular mode are handled by the CRTC registers, which are set by
 * the "gfx_vga_restore" routine.   Most OSs that use VGA to set modes save
 * and restore the standard VGA registers themselves, which is why these
 * registers are not part of the save/restore paradigm.
 *-----------------------------------------------------------------------------
 */
int
gfx_vga_set_graphics_bits(void)
{
   /* SET GRAPHICS BIT IN GRAPHICS CONTROLLER REG 0x06 */

   OUTB(0x3CE, 0x06);
   OUTB(0x3CF, 0x01);

   /* SET GRAPHICS BIT IN ATTRIBUTE CONTROLLER REG 0x10 */

   INB(0x3BA);				/* Reset flip-flop */
   INB(0x3DA);
   OUTB(0x3C0, 0x10);
   OUTB(0x3C0, 0x01);
   return (GFX_STATUS_OK);
}

/*-----------------------------------------------------------------------------
 * gfx_vga_mode
 *
 * This routine searches the VGA mode table for a match of the specified 
 * mode and then fills in the VGA structure with the associated VGA register 
 * values.  The "gfx_vga_restore" routine can then be called to actually 
 * set the mode.
 *-----------------------------------------------------------------------------
 */
int
gfx_vga_mode(gfx_vga_struct * vga, int xres, int yres, int bpp, int hz)
{
   unsigned int i;
   unsigned short pitch;

   for (i = 0; i < GFX_VGA_MODES; i++) {
      if ((gfx_vga_modes[i].xsize == xres) &&
	  (gfx_vga_modes[i].ysize == yres) && (gfx_vga_modes[i].hz == hz)) {
	 /* COPY ENTIRE STRUCTURE FROM THE TABLE */

	 *vga = gfx_vga_modes[i];

	 /* SET PITCH TO 1K OR 2K */
	 /* CRTC_EXTENDED_OFFSET index is 0x45, so offset = 0x05 */

	 pitch = (unsigned short)xres;
	 if (bpp > 8)
	    pitch <<= 1;
	 if (pitch <= 1024)
	    pitch = 1024 >> 3;
	 else
	    pitch = 2048 >> 3;
	 vga->stdCRTCregs[0x13] = (unsigned char)pitch;
	 vga->extCRTCregs[0x05] = (unsigned char)((pitch >> 8) & 0x03);

	 /* SET PROPER COLOR DEPTH VALUE */
	 /* CRTC_EXTENDED_COLOR_CONTROL index is 0x46, so offset = 0x06 */

	 switch (bpp) {
	 case 15:
	    vga->extCRTCregs[0x06] = CRTC_BIT_16BPP | CRTC_BIT_555;
	    break;
	 case 16:
	    vga->extCRTCregs[0x06] = CRTC_BIT_16BPP;
	    break;
	 default:
	    vga->extCRTCregs[0x06] = 0;
	    break;
	 }
	 return (GFX_STATUS_OK);
      }
   }
   return (GFX_STATUS_UNSUPPORTED);
}

/*-----------------------------------------------------------------------------
 * gfx_vga_pitch
 *
 * This routine updates the VGA regisers in the specified VGA structure for 
 * the specified pitch.  It does not program the hardware.
 *-----------------------------------------------------------------------------
 */
int
gfx_vga_pitch(gfx_vga_struct * vga, unsigned short pitch)
{
   pitch >>= 3;
   vga->stdCRTCregs[0x13] = (unsigned char)pitch;
   vga->extCRTCregs[0x05] = (unsigned char)((pitch >> 8) & 0x03);
   return (0);
}

/*-----------------------------------------------------------------------------
 * gfx_vga_save
 *
 * This routine saves the state of the VGA registers into the specified 
 * structure.  Flags indicate what portions of the register state need to 
 * be saved.
 *-----------------------------------------------------------------------------
 */
int
gfx_vga_save(gfx_vga_struct * vga, int flags)
{
   int i;
   unsigned short crtcindex, crtcdata;

   crtcindex = (INB(0x3CC) & 0x01) ? 0x3D4 : 0x3B4;
   crtcdata = crtcindex + 1;

   /* CHECK MISCELLANEOUS OUTPUT FLAG */

   if (flags & GFX_VGA_FLAG_MISC_OUTPUT) {
      /* SAVE MISCCELLANEOUS OUTPUT REGISTER */

      vga->miscOutput = INB(0x3CC);
   }

   /* CHECK STANDARD CRTC FLAG */

   if (flags & GFX_VGA_FLAG_STD_CRTC) {
      /* SAVE STANDARD CRTC REGISTERS */

      for (i = 0; i < GFX_STD_CRTC_REGS; i++) {
	 OUTB(crtcindex, (unsigned char)i);
	 vga->stdCRTCregs[i] = INB(crtcdata);
      }
   }

   /* CHECK EXTENDED CRTC FLAG */

   if (flags & GFX_VGA_FLAG_EXT_CRTC) {
      /* SAVE EXTENDED CRTC REGISTERS */

      for (i = 0; i < GFX_EXT_CRTC_REGS; i++) {
	 OUTB(crtcindex, (unsigned char)(0x40 + i));
	 vga->extCRTCregs[i] = INB(crtcdata);
      }
   }
   return (0);
}

/*-----------------------------------------------------------------------------
 * gfx_vga_clear_extended
 *
 * This routine clears the extended SoftVGA register values to have SoftVGA
 * behave like standard VGA. 
 *-----------------------------------------------------------------------------
 */
void
gfx_vga_clear_extended(void)
{
   int i;
   unsigned short crtcindex, crtcdata;

   crtcindex = (INB(0x3CC) & 0x01) ? 0x3D4 : 0x3B4;
   crtcdata = crtcindex + 1;

   OUTB(crtcindex, 0x30);
   OUTB(crtcdata, 0x57);
   OUTB(crtcdata, 0x4C);
   for (i = 0x40; i <= 0x4F; i++) {
      OUTB(crtcindex, (unsigned char)i);
      OUTB(crtcdata, 0);
   }
   OUTB(crtcindex, 0x30);
   OUTB(crtcdata, 0x00);
}

/*-----------------------------------------------------------------------------
 * gfx_vga_restore
 *
 * This routine restores the state of the VGA registers from the specified
 * structure.  Flags indicate what portions of the register state need to 
 * be saved.
 *-----------------------------------------------------------------------------
 */
int
gfx_vga_restore(gfx_vga_struct * vga, int flags)
{
   int i;
   unsigned short crtcindex, crtcdata;

   crtcindex = (INB(0x3CC) & 0x01) ? 0x3D4 : 0x3B4;
   crtcdata = crtcindex + 1;

   /* CHECK MISCELLANEOUS OUTPUT FLAG */

   if (flags & GFX_VGA_FLAG_MISC_OUTPUT) {
      /* RESTORE MISCELLANEOUS OUTPUT REGISTER VALUE */

      OUTB(0x3C2, vga->miscOutput);
   }

   /* CHECK STANDARD CRTC FLAG */

   if (flags & GFX_VGA_FLAG_STD_CRTC) {
      /* UNLOCK STANDARD CRTC REGISTERS */

      OUTB(crtcindex, 0x11);
      OUTB(crtcdata, 0);

      /* RESTORE STANDARD CRTC REGISTERS */

      for (i = 0; i < GFX_STD_CRTC_REGS; i++) {
	 OUTB(crtcindex, (unsigned char)i);
	 OUTB(crtcdata, vga->stdCRTCregs[i]);
      }
   }

   /* CHECK EXTENDED CRTC FLAG */

   if (flags & GFX_VGA_FLAG_EXT_CRTC) {
      /* UNLOCK EXTENDED CRTC REGISTERS */

      OUTB(crtcindex, 0x30);
      OUTB(crtcdata, 0x57);
      OUTB(crtcdata, 0x4C);

      /* RESTORE EXTENDED CRTC REGISTERS */

      for (i = 0; i < GFX_EXT_CRTC_REGS; i++) {
	 OUTB(crtcindex, (unsigned char)(0x40 + i));
	 OUTB(crtcdata, vga->extCRTCregs[i]);
      }

      /* LOCK EXTENDED CRTC REGISTERS */

      OUTB(crtcindex, 0x30);
      OUTB(crtcdata, 0x00);

      /* CHECK IF DIRECT FRAME BUFFER MODE (VESA MODE) */

      if (vga->extCRTCregs[0x03] & 1) {
	 /* SET BORDER COLOR TO BLACK */
	 /* This really should be another thing saved/restored, but */
	 /* Durango currently doesn't do the attr controller registers. */

	 INB(0x3BA);			/* Reset flip-flop */
	 INB(0x3DA);
	 OUTB(0x3C0, 0x11);
	 OUTB(0x3C0, 0x00);
      }
   }
   return (0);
}

/*-----------------------------------------------------------------------------
 * gfx_vga_mode_switch
 *
 * This routine programs the SoftVGA register to indicate that a mode switch
 * is in progress.  This results in a cleaner mode switch since SoftVGA will 
 * not validate the hardware with intermediate values.
 *-----------------------------------------------------------------------------
 */
int
gfx_vga_mode_switch(int active)
{
   unsigned short crtcindex, crtcdata;

   crtcindex = (INB(0x3CC) & 0x01) ? 0x3D4 : 0x3B4;
   crtcdata = crtcindex + 1;

   /* UNLOCK EXTENDED CRTC REGISTERS */

   OUTB(crtcindex, CRTC_EXTENDED_REGISTER_LOCK);
   OUTB(crtcdata, 0x57);
   OUTB(crtcdata, 0x4C);

   /* SIGNAL THE BEGINNING OR END OF THE MODE SWITCH */
   /* SoftVGA will hold off validating the back end hardware. */

   OUTB(crtcindex, CRTC_MODE_SWITCH_CONTROL);
   active = active ? 1 : 0;
   OUTB(crtcdata, (unsigned char)active);

   /* WAIT UNTIL SOFTVGA HAS VALIDATED MODE IF ENDING MODE SWITCH */
   /* This is for VSA1 only, where SoftVGA waits until the next */
   /* vertical blank to validate the hardware state. */

   if ((!active) && (!(gu1_detect_vsa2()))) {
      OUTB(crtcindex, 0x33);
      while (INB(crtcdata) & 0x80) ;
   }

   /* LOCK EXTENDED CRTC REGISTERS */

   OUTB(crtcindex, CRTC_EXTENDED_REGISTER_LOCK);
   OUTB(crtcdata, 0x00);
   return (0);
}

/*-----------------------------------------------------------------------------
 * gu1_detect_vsa2
 *
 * This routine detects if VSA2 is present.  The interface to SoftVGA 
 * changed slightly.
 *-----------------------------------------------------------------------------
 */
int
gu1_detect_vsa2(void)
{
   unsigned short crtcindex, crtcdata;

   crtcindex = (INB(0x3CC) & 0x01) ? 0x3D4 : 0x3B4;
   crtcdata = crtcindex + 1;
   OUTB(crtcindex, 0x35);
   if (INB(crtcdata) != 'C')
      return (0);
   OUTB(crtcindex, 0x36);
   if (INB(crtcdata) != 'X')
      return (0);
   return (1);
}

/* END OF FILE */