vga3dfx.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "../port/error.h"

#define	Image	IMAGE
#include <draw.h>
#include <memdraw.h>
#include <cursor.h>
#include "screen.h"

typedef struct Cursor3dfx Cursor3dfx;
struct Cursor3dfx {
	int	vidProcCfg;
	int	hwCurPatAddr;
	int	hwCurLoc;
	int	hwCurC0;
	int	hwCurC1;
};

enum {
	dramInit0	= 0x18,
	dramInit1	= 0x1C,

	hwCur		= 0x5C,
};

static void
tdfxenable(VGAscr* scr)
{
	Pcidev *p;
	int i, *mmio;

	if(scr->mmio)
		return;
	if(p = pcimatch(nil, 0x121A, 0)){
		switch(p->did){
		case 0x0003:		/* Banshee */
		case 0x0005:		/* Avenger (a.k.a. Voodoo3) */
			break;
		default:
			return;
		}
	}
	else
		return;
	
	scr->mmio = vmap(p->mem[0].bar&~0x0F, p->mem[0].size);
	if(scr->mmio == nil)
		return;
	scr->pci = p;
	
	addvgaseg("3dfxmmio", p->mem[0].bar&~0x0F, p->mem[0].size);
	vgalinearpci(scr);
	if(scr->apsize)
		addvgaseg("3dfxscreen", scr->paddr, scr->apsize);

	/*
	 * Find a place for the cursor data in display memory.
	 * If SDRAM then there's 16MB memory else it's SGRAM
	 * and can count it based on the power-on straps -
	 * chip size can be 8Mb or 16Mb, and there can be 4 or
	 * 8 of them.
	 * Use the last 1KB of the framebuffer.
	 */
	mmio = (void*)((uchar*)scr->mmio+dramInit0);
	if(*(mmio+1) & 0x40000000)
		i = 16*1024*1024;
	else{
		if(*mmio & 0x08000000)
			i = 16*1024*1024/8;
		else
			i = 8*1024*1024/8;
		if(*mmio & 0x04000000)
			i *= 8;
		else
			i *= 4;
	}
	scr->storage = i - 1024;
}

static void
tdfxcurdisable(VGAscr* scr)
{
	Cursor3dfx *cursor3dfx;

	if(scr->mmio == 0)
		return;
	cursor3dfx = (void*)((uchar*)scr->mmio+hwCur);
	cursor3dfx->vidProcCfg &= ~0x08000000;
}

static void
tdfxcurload(VGAscr* scr, Cursor* curs)
{
	int y;
	uchar *p;
	Cursor3dfx *cursor3dfx;

	if(scr->mmio == 0)
		return;
	cursor3dfx = (void*)((uchar*)scr->mmio+hwCur);

	/*
	 * Disable the cursor then load the new image in
	 * the top-left of the 64x64 array.
	 * The cursor data is stored in memory as 128-bit
	 * words consisting of plane 0 in the least significant 64-bits
	 * and plane 1 in the most significant.
	 * The X11 cursor truth table is:
	 *	p0 p1	colour
	 *	 0  0	transparent
	 *	 0  1	transparent
	 *	 1  0	hwCurC0
	 *	 1  1	hwCurC1
	 * Unused portions of the image have been initialised to be
	 * transparent.
	 */
	cursor3dfx->vidProcCfg &= ~0x08000000;
	p = (uchar*)scr->vaddr + scr->storage;
	for(y = 0; y < 16; y++){
		*p++ = curs->clr[2*y]|curs->set[2*y];
		*p++ = curs->clr[2*y+1]|curs->set[2*y+1];
		p += 6;
		*p++ = curs->set[2*y];
		*p++ = curs->set[2*y+1];
		p += 6;
	}

	/*
	 * Save the cursor hotpoint and enable the cursor.
	 * The 0,0 cursor point is bottom-right.
	 */
	scr->offset.x = 63+curs->offset.x;
	scr->offset.y = 63+curs->offset.y;
	cursor3dfx->vidProcCfg |= 0x08000000;
}

static int
tdfxcurmove(VGAscr* scr, Point p)
{
	Cursor3dfx *cursor3dfx;

	if(scr->mmio == 0)
		return 1;
	cursor3dfx = (void*)((uchar*)scr->mmio+hwCur);

	cursor3dfx->hwCurLoc = ((p.y+scr->offset.y)<<16)|(p.x+scr->offset.x);

	return 0;
}

static void
tdfxcurenable(VGAscr* scr)
{
	Cursor3dfx *cursor3dfx;

	tdfxenable(scr);
	if(scr->mmio == 0)
		return;
	cursor3dfx = (void*)((uchar*)scr->mmio+hwCur);

	/*
	 * Cursor colours.
	 */
	cursor3dfx->hwCurC0 = 0xFFFFFFFF;
	cursor3dfx->hwCurC1 = 0x00000000;

	/*
	 * Initialise the 64x64 cursor to be transparent (X11 mode).
	 */
	cursor3dfx->hwCurPatAddr = scr->storage;
	memset((uchar*)scr->vaddr + scr->storage, 0, 64*16);

	/*
	 * Load, locate and enable the 64x64 cursor in X11 mode.
	 */
	tdfxcurload(scr, &arrow);
	tdfxcurmove(scr, ZP);
	cursor3dfx->vidProcCfg |= 0x08000002;
}

VGAdev vga3dfxdev = {
	"3dfx",

	tdfxenable,
	nil,
	nil,
	nil,
};

VGAcur vga3dfxcur = {
	"3dfxhwgc",

	tdfxcurenable,
	tdfxcurdisable,
	tdfxcurload,
	tdfxcurmove,
};