/*
 *       ______             ____  ______     _____  ______
 *      |  ____|           |  _ \|  ____|   / / _ \|  ____|
 *      | |__ _ __ ___  ___| |_) | |__     / / |_| | |__
 *      |  __| '__/ _ \/ _ \  _ <|  __|   / /|  _  |  __|
 *      | |  | | |  __/  __/ |_) | |____ / / | | | | |
 *      |_|  |_|  \___|\___|____/|______/_/  |_| |_|_|
 *
 *
 *      Paradise driver (based on the Allegro Paradise code).
 *
 *      By Francois Charton and Shawn Hargreaves.
 *
 *      See freebe.txt for copyright information.
 */

// #define NO_HWPTR

#include <pc.h>

#include "vbeaf.h"

/* chipset information */
#define PVGA1 1
#define WD90C 2

int paradise_type = 0;

/* driver function prototypes */
void CirrusSetBank32( );
void CirrusSetBank32End( );
void CirrusSetBank(AF_DRIVER *af, long bank);
void ParadiseSetBank32( );
void ParadiseSetBank32End( );
void ParadiseSetBank(AF_DRIVER *af, long bank);
int ExtStub( );
long GetVideoModeInfo(AF_DRIVER *af, short mode, AF_MODE_INFO *modeInfo);
long SetVideoMode(AF_DRIVER *af, short mode, long virtualX, long virtualY,
                  long *bytesPerLine, int numBuffers, AF_CRTCInfo *crtc);
void RestoreTextMode(AF_DRIVER *af);
long GetClosestPixelClock(AF_DRIVER *af, short mode, unsigned long pixelClock);
void SaveRestoreState(AF_DRIVER *af, int subfunc, void *saveBuf);
void SetDisplayStart(AF_DRIVER *af, long x, long y, long waitVRT);
void SetActiveBuffer(AF_DRIVER *af, long index);
void SetVisibleBuffer(AF_DRIVER *af, long index, long waitVRT);
int GetDisplayStartStatus(AF_DRIVER *af);
void SetPaletteData(AF_DRIVER *af, AF_PALETTE *pal, long num, long index,
                    long waitVRT);

/* list which ports we are going to access (only needed under Linux) */
unsigned short ports_table[] = { 0xFFFF };

/* internal driver state variables */
int af_bpp;
int af_width;
int af_height;
int af_visible_page;
int af_active_page;
int af_scroll_x;
int af_scroll_y;
int af_bank;

/* FreeBE/AF extension allowing farptr access to video memory */
FAF_HWPTR_DATA hwptr;

/* list of available video modes */
typedef struct VIDEO_MODE {
	int w, h;
	int bpp;
	int num;
} VIDEO_MODE;

VIDEO_MODE mode_list[] = { { 640, 400, 8, 0x5E },
	                       { 640, 480, 8, 0x5F },
	                       { 800, 600, 8, 0x5C } };

#define NUM_MODES (int)(sizeof(mode_list) / sizeof(VIDEO_MODE))

short available_modes[NUM_MODES + 1] = { 1, 2, 3, -1 };

/* detect:
 *  Detects the presence of a Paradise card.
 */
char *detect(unsigned long *vidmem) {
	char *name = NULL;
	RM_REGS r;
	int old, old2;

	old = read_vga_register(0x3CE, 0xF);
	write_vga_register(0x3CE, 0xF, old | 0x17); /* lock extended registers */

	if (test_vga_register(0x3CE, 0x9, 0x7F)) { /* not a Paradise card! */
		write_vga_register(0x3CE, 0xF, old);
		return NULL;
	}

	alter_vga_register(0x3CE, 0xF, 0x17, 5); /* unlock extended regs */

	if (!test_vga_register(0x3CE, 0x9, 0x7F)) { /* not a Paradise card! */
		write_vga_register(0x3CE, 0xF, old);
		return NULL;
	}

	old2 = read_vga_register(0x3D4, 0x29);
	alter_vga_register(0x3D4, 0x29, 0x8F, 0x85);

	if (!test_vga_register(0x3D4, 0x2B, 0xFF)) {
		paradise_type = PVGA1;
		name = "PVGA1";
		goto end;
	}

	write_vga_register(0x3C4, 0x06, 0x48);

	if (!test_vga_register(0x3C4, 0x7, 0xF0)) {
		paradise_type = PVGA1;
		name = "WD90C0x";
		goto end;
	}

	if (!test_vga_register(0x3C4, 0x10, 0xFF)) {
		paradise_type = PVGA1;
		name = "WD90C2x";
		write_vga_register(0x3D4, 0x34, 0xA6);
		if (read_vga_register(0x3D4, 0x32) & 0x20)
			write_vga_register(0x3D4, 0x34, 0);
		goto end;
	}

	paradise_type = WD90C;
	name = "WD90C1x or 24+";

end:

	write_vga_register(0x3D4, 0x29, old2);
	write_vga_register(0x3CE, 0xF, old);

	r.x.ax = 0x007F;
	r.h.bh = 0x02;
	rm_int(0x10, &r);
	*vidmem = r.h.ch * 64;

	return name;
}

/* SetupDriver:
 *  Fills in our driver header block.
 */
int SetupDriver(AF_DRIVER *af) {
	char *name;
	int i;

	name = detect(&af->TotalMemory);

	if (!name) return 1;

	i = 0;
	while (af->OemVendorName[i]) i++;

	af->OemVendorName[i++] = ',';
	af->OemVendorName[i++] = ' ';

	while (*name) af->OemVendorName[i++] = *(name++);

	af->OemVendorName[i] = 0;

	af->AvailableModes = available_modes;

	af->Attributes =
	    (afHaveMultiBuffer | afHaveVirtualScroll | afHaveBankedBuffer);

	af->BankSize = 64;
	af->BankedBasePtr = 0xA0000;

	af->IOPortsTable = ports_table;

	if (paradise_type == PVGA1) {
		af->SetBank32 = CirrusSetBank32;
		af->SetBank32Len = (long)CirrusSetBank32End - (long)CirrusSetBank32;
		af->SetBank = CirrusSetBank;
	} else {
		af->SetBank32 = ParadiseSetBank32;
		af->SetBank32Len = (long)ParadiseSetBank32End - (long)ParadiseSetBank32;
		af->SetBank = ParadiseSetBank;
	}

	af->SupplementalExt = ExtStub;
	af->GetVideoModeInfo = GetVideoModeInfo;
	af->SetVideoMode = SetVideoMode;
	af->RestoreTextMode = RestoreTextMode;
	af->GetClosestPixelClock = GetClosestPixelClock;
	af->SaveRestoreState = SaveRestoreState;
	af->SetDisplayStart = SetDisplayStart;
	af->SetActiveBuffer = SetActiveBuffer;
	af->SetVisibleBuffer = SetVisibleBuffer;
	af->GetDisplayStartStatus = GetDisplayStartStatus;
	af->SetPaletteData = SetPaletteData;

	return 0;
}

/* InitDriver:
 *  The second thing to be called during the init process, after the
 *  application has mapped all the memory and I/O resources we need.
 */
int InitDriver(AF_DRIVER *af) {
	hwptr_init(hwptr.IOMemMaps[0], af->IOMemMaps[0]);
	hwptr_init(hwptr.IOMemMaps[1], af->IOMemMaps[1]);
	hwptr_init(hwptr.IOMemMaps[2], af->IOMemMaps[2]);
	hwptr_init(hwptr.IOMemMaps[3], af->IOMemMaps[3]);
	hwptr_init(hwptr.BankedMem, af->BankedMem);
	hwptr_init(hwptr.LinearMem, af->LinearMem);

	return 0;
}

/* FreeBEX:
 *  Returns an interface structure for the requested FreeBE/AF extension.
 */
void *FreeBEX(AF_DRIVER *af, unsigned long id) {
	switch (id) {
#ifndef NO_HWPTR

		case FAFEXT_HWPTR:
			/* allow farptr access to video memory */
			return &hwptr;

#endif

		default: return NULL;
	}
}

/* ExtStub:
 *  Vendor-specific extension hook: we don't provide any.
 */
int ExtStub( ) {
	return 0;
}

/* GetVideoModeInfo:
 *  Retrieves information about this video mode, returning zero on success
 *  or -1 if the mode is invalid.
 */
long GetVideoModeInfo(AF_DRIVER *af, short mode, AF_MODE_INFO *modeInfo) {
	VIDEO_MODE *info;
	int i;

	if ((mode <= 0) || (mode > NUM_MODES)) return -1;

	info = &mode_list[mode - 1];

	for (i = 0; i < (int)sizeof(AF_MODE_INFO); i++) ((char *)modeInfo)[i] = 0;

	modeInfo->Attributes =
	    (afHaveMultiBuffer | afHaveVirtualScroll | afHaveBankedBuffer);

	modeInfo->XResolution = info->w;
	modeInfo->YResolution = info->h;
	modeInfo->BitsPerPixel = info->bpp;

	modeInfo->MaxBuffers = (af->TotalMemory * 1024) /
	                       (info->w * info->h * BYTES_PER_PIXEL(info->bpp));

	if (info->w > 1024) {
		modeInfo->MaxBytesPerScanLine = 2048 * BYTES_PER_PIXEL(info->bpp);
		modeInfo->MaxScanLineWidth = 2048;
	} else {
		modeInfo->MaxBytesPerScanLine = 1024 * BYTES_PER_PIXEL(info->bpp);
		modeInfo->MaxScanLineWidth = 1024;
	}

	modeInfo->BytesPerScanLine = info->w * BYTES_PER_PIXEL(info->bpp);
	modeInfo->BnkMaxBuffers = modeInfo->MaxBuffers;

	modeInfo->MaxPixelClock = 135000000;

	return 0;
}

/* SetVideoMode:
 *  Sets the specified video mode, returning zero on success.
 */
long SetVideoMode(AF_DRIVER *af, short mode, long virtualX, long virtualY,
                  long *bytesPerLine, int numBuffers, AF_CRTCInfo *crtc) {
	long available_vram;
	long used_vram;
	int width;
	VIDEO_MODE *info;
	RM_REGS r;

	/* reject anything with hardware stereo, linear framebuffer, or noclear */
	if (mode & 0xC400) return -1;

	mode &= 0x3FF;

	if ((mode <= 0) || (mode > NUM_MODES)) return -1;

	info = &mode_list[mode - 1];

	/* call BIOS to set the mode */
	r.x.ax = info->num;
	rm_int(0x10, &r);

	/* adjust the virtual width for widescreen modes */
	if (virtualX > info->w) {
		if (virtualX > 1024) return -1;

		*bytesPerLine = ((virtualX * BYTES_PER_PIXEL(info->bpp)) + 15) & 0xFFF0;

		width = read_vga_register(0x3D4, 0x13);
		write_vga_register(0x3D4, 0x13,
		                   (width * (*bytesPerLine)) /
		                       (info->w * BYTES_PER_PIXEL(info->bpp)));
	} else
		*bytesPerLine = info->w * BYTES_PER_PIXEL(info->bpp);

	/* set up some hardware registers */
	if (paradise_type != PVGA1) {
		write_vga_register(0x3C4, 0x06, 0x48);

		alter_vga_register(0x3C4, 0x11, 0x80, 0x80);
		alter_vga_register(0x3CE, 0x0B, 0x80, 0x80);

		write_vga_register(0x3C4, 0x06, 0x00);
	}

	/* store info about the current mode */
	af_bpp = info->bpp;
	af_width = *bytesPerLine;
	af_height = MAX(info->h, virtualY);
	af_visible_page = 0;
	af_active_page = 0;
	af_scroll_x = 0;
	af_scroll_y = 0;
	af_bank = -1;

	af->BufferEndX = af_width / BYTES_PER_PIXEL(af_bpp) - 1;
	af->BufferEndY = af_height - 1;
	af->OriginOffset = 0;

	used_vram = af_width * af_height * numBuffers;
	available_vram = af->TotalMemory * 1024;

	if (used_vram > available_vram) return -1;

	if (available_vram - used_vram >= af_width) {
		af->OffscreenOffset = used_vram;
		af->OffscreenStartY = af_height * numBuffers;
		af->OffscreenEndY = available_vram / af_width - 1;
	} else {
		af->OffscreenOffset = 0;
		af->OffscreenStartY = 0;
		af->OffscreenEndY = 0;
	}

	return 0;
}

/* RestoreTextMode:
 *  Returns to text mode, shutting down the accelerator hardware.
 */
void RestoreTextMode(AF_DRIVER *af) {
	RM_REGS r;

	r.x.ax = 3;
	rm_int(0x10, &r);
}

/* GetClosestPixelClock:
 *  I don't have a clue what this should return: it is used for the
 *  refresh rate control.
 */
long GetClosestPixelClock(AF_DRIVER *af, short mode, unsigned long pixelClock) {
	/* ??? */
	return 135000000;
}

/* SaveRestoreState:
 *  Stores the current driver status: not presently implemented.
 */
void SaveRestoreState(AF_DRIVER *af, int subfunc, void *saveBuf) {
	/* not implemented (not used by Allegro) */
}

/* SetDisplayStart:
 *  Hardware scrolling function. The waitVRT value may be one of:
 *
 *    -1 = don't set hardware, just store values for next page flip to use
 *     0 = set values and return immediately
 *     1 = set values and wait for retrace
 */
void SetDisplayStart(AF_DRIVER *af, long x, long y, long waitVRT) {
	if (waitVRT >= 0) {
		long a = (x * BYTES_PER_PIXEL(af_bpp)) +
		         ((y + af_visible_page * af_height) * af_width);

		asm volatile("cli");

		if (waitVRT) {
			do { } while (inportb(0x3DA) & 1); }

		/* write high bits to Paradise register 3CE indx 0xD, bits 3-4 */
		alter_vga_register(0x3CE, 0x0D, 0x18, a >> 15);

		/* write to normal VGA address registers */
		write_vga_register(0x3D4, 0x0D, (a >> 2) & 0xFF);
		write_vga_register(0x3D4, 0x0C, (a >> 10) & 0xFF);

		asm volatile("sti");

		if (waitVRT) {
			do { } while (!(inportb(0x3DA) & 8)); }
	}

	af_scroll_x = x;
	af_scroll_y = y;
}

/* SetActiveBuffer:
 *  Sets which buffer is being drawn onto, for use in multi buffering
 *  systems (not used by Allegro).
 */
void SetActiveBuffer(AF_DRIVER *af, long index) {
	if (af->OffscreenOffset) {
		af->OffscreenStartY += af_active_page * af_height;
		af->OffscreenEndY += af_active_page * af_height;
	}

	af_active_page = index;

	af->OriginOffset = af_width * af_height * index;

	if (af->OffscreenOffset) {
		af->OffscreenStartY -= af_active_page * af_height;
		af->OffscreenEndY -= af_active_page * af_height;
	}
}

/* SetVisibleBuffer:
 *  Sets which buffer is displayed on the screen, for use in multi buffering
 *  systems (not used by Allegro).
 */
void SetVisibleBuffer(AF_DRIVER *af, long index, long waitVRT) {
	af_visible_page = index;

	SetDisplayStart(af, af_scroll_x, af_scroll_y, waitVRT);
}

/* GetDisplayStartStatus:
 *  Status poll for triple buffering. Not possible on the majority of
 *  present cards: this function is just a placeholder.
 */
int GetDisplayStartStatus(AF_DRIVER *af) {
	return 1;
}

/* SetPaletteData:
 *  Palette setting routine.
 */
void SetPaletteData(AF_DRIVER *af, AF_PALETTE *pal, long num, long index,
                    long waitVRT) {
	int i;

	if (waitVRT) {
		do {
		} while (inportb(0x3DA) & 8);

		do { } while (!(inportb(0x3DA) & 8)); }

	for (i = 0; i < num; i++) {
		outportb(0x3C8, index + i);
		outportb(0x3C9, pal[i].red / 4);
		outportb(0x3C9, pal[i].green / 4);
		outportb(0x3C9, pal[i].blue / 4);
	}
}

/* CirrusSetBank32:
 *  Relocatable bank switch function, called with a bank number in %edx.
 */

asm ("

   .globl _CirrusSetBank32, _CirrusSetBank32End

      .align 4
   _CirrusSetBank32:
      pushl %edx
      pushl %eax
      pushl %edx

      movl $0x3CE, %edx          /* 3CE index 0x9 */
      movb $0x9, %al
      outb %al, %dx

      popl %eax                  /* write bank number */
      shll $4, %eax
      incl %edx
      outb %al, %dx

      popl %eax
      popl %edx
      ret

   _CirrusSetBank32End:

");



/* CirrusSetBank:
 *  C-callable bank switch function. This version simply chains to the
 *  relocatable CirrusSetBank32() above.
 */
void CirrusSetBank(AF_DRIVER *af, long bank)
{
	asm(" call _CirrusSetBank32 " : : "d"(bank));

	af_bank = bank;
}



/* ParadiseSetBank32:
 *  Relocatable bank switch function, called with a bank number in %edx.
 */

asm ("

   .globl _ParadiseSetBank32, _ParadiseSetBank32End

      .align 4
   _ParadiseSetBank32:
      pushl %eax
      pushl %ecx
      pushl %edx

      movl %edx, %ecx
      shll $4, %ecx

      movl $0x3CE, %edx          /* 3CE index 0x9 */
      movb $0x9, %al
      outb %al, %dx

      movl %ecx, %eax            /* set read bank number */
      incl %edx
      outb %al, %dx

      decl %edx                  /* 3CE index 0xA */
      movb $0xA, %al
      outb %al, %dx

      movl %ecx, %eax            /* set write bank number */
      incl %edx
      outb %al, %dx

      popl %edx
      popl %ecx
      popl %eax
      ret

   _ParadiseSetBank32End:

");



/* ParadiseSetBank:
 *  C-callable bank switch function. This version simply chains to the
 *  relocatable ParadiseSetBank32() above.
 */
void ParadiseSetBank(AF_DRIVER *af, long bank)
{
	asm(" call _ParadiseSetBank32 " : : "d"(bank));

	af_bank = bank;
}