vga16fb.c

Linux环境下视频显示卡设备的驱动程序源代码

        dx = area->dx / 4;
        width = area->width / 4;

        if (area->dy < area->sy || (area->dy == area->sy && dx < sx)) {
                line_ofs = info->fix.line_length - width;
                dest = info->screen_base + dx + area->dy * info->fix.line_length;
                src = info->screen_base + sx + area->sy * info->fix.line_length;
                while (height--) {
                        for (x = 0; x < width; x++) {
                                readb(src);
                                writeb(0, dest);
                                src++;
                                dest++;
                        }
                        src += line_ofs;
                        dest += line_ofs;
                }
        } else {
                line_ofs = info->fix.line_length - width;
                dest = info->screen_base + dx + width +
			(area->dy + height - 1) * info->fix.line_length;
                src = info->screen_base + sx + width +
			(area->sy + height - 1) * info->fix.line_length;
                while (height--) {
                        for (x = 0; x < width; x++) {
                                --src;
                                --dest;
                                readb(src);
                                writeb(0, dest);
                        }
                        src -= line_ofs;
                        dest -= line_ofs;
                }
        }

        setsr(oldsr);
        setop(oldop);
        setmode(oldmode);
        setindex(oldindex);
}

static void vga16fb_copyarea(struct fb_info *info, const struct fb_copyarea *area)
{
	u32 dx = area->dx, dy = area->dy, sx = area->sx, sy = area->sy; 
	int x, x2, y2, old_dx, old_dy, vxres, vyres;
	int height, width, line_ofs;
	char __iomem *dst = NULL;
	char __iomem *src = NULL;

	vxres = info->var.xres_virtual;
	vyres = info->var.yres_virtual;

	if (area->dx > vxres || area->sx > vxres || area->dy > vyres ||
	    area->sy > vyres)
		return;

	/* clip the destination */
	old_dx = area->dx;
	old_dy = area->dy;

	/*
	 * We could use hardware clipping but on many cards you get around
	 * hardware clipping by writing to framebuffer directly.
	 */
	x2 = area->dx + area->width;
	y2 = area->dy + area->height;
	dx = area->dx > 0 ? area->dx : 0;
	dy = area->dy > 0 ? area->dy : 0;
	x2 = x2 < vxres ? x2 : vxres;
	y2 = y2 < vyres ? y2 : vyres;
	width = x2 - dx;
	height = y2 - dy;

	if (sx + dx < old_dx || sy + dy < old_dy)
		return;

	/* update sx1,sy1 */
	sx += (dx - old_dx);
	sy += (dy - old_dy);

	/* the source must be completely inside the virtual screen */
	if (sx + width > vxres || sy + height > vyres)
		return;

	switch (info->fix.type) {
	case FB_TYPE_VGA_PLANES:
		if (info->fix.type_aux == FB_AUX_VGA_PLANES_VGA4) {
			width = width/8;
			height = height;
			line_ofs = info->fix.line_length - width;

			setmode(1);
			setop(0);
			setsr(0xf);

			if (dy < sy || (dy == sy && dx < sx)) {
				dst = info->screen_base + (dx/8) + dy * info->fix.line_length;
				src = info->screen_base + (sx/8) + sy * info->fix.line_length;
				while (height--) {
					for (x = 0; x < width; x++) {
						readb(src);
						writeb(0, dst);
						dst++;
						src++;
					}
					src += line_ofs;
					dst += line_ofs;
				}
			} else {
				dst = info->screen_base + (dx/8) + width + 
					(dy + height - 1) * info->fix.line_length;
				src = info->screen_base + (sx/8) + width + 
					(sy + height  - 1) * info->fix.line_length;
				while (height--) {
					for (x = 0; x < width; x++) {
						dst--;
						src--;
						readb(src);
						writeb(0, dst);
					}
					src -= line_ofs;
					dst -= line_ofs;
				}
			}
		} else 
			vga_8planes_copyarea(info, area);
		break;
	case FB_TYPE_PACKED_PIXELS:
	default:
		cfb_copyarea(info, area);
		break;
	}
}

#define TRANS_MASK_LOW  {0x0,0x8,0x4,0xC,0x2,0xA,0x6,0xE,0x1,0x9,0x5,0xD,0x3,0xB,0x7,0xF}
#define TRANS_MASK_HIGH {0x000, 0x800, 0x400, 0xC00, 0x200, 0xA00, 0x600, 0xE00, \
			 0x100, 0x900, 0x500, 0xD00, 0x300, 0xB00, 0x700, 0xF00}

#if defined(__LITTLE_ENDIAN)
static const u16 transl_l[] = TRANS_MASK_LOW;
static const u16 transl_h[] = TRANS_MASK_HIGH;
#elif defined(__BIG_ENDIAN)
static const u16 transl_l[] = TRANS_MASK_HIGH;
static const u16 transl_h[] = TRANS_MASK_LOW;
#else
#error "Only __BIG_ENDIAN and __LITTLE_ENDIAN are supported in vga-planes"
#endif

static void vga_8planes_imageblit(struct fb_info *info, const struct fb_image *image)
{
        char oldindex = getindex();
        char oldmode = setmode(0x40);
        char oldop = setop(0);
        char oldsr = setsr(0);
        char oldmask = selectmask();
        const char *cdat = image->data;
	u32 dx = image->dx;
        char __iomem *where;
        int y;

        dx /= 4;
        where = info->screen_base + dx + image->dy * info->fix.line_length;

        setmask(0xff);
        writeb(image->bg_color, where);
        readb(where);
        selectmask();
        setmask(image->fg_color ^ image->bg_color);
        setmode(0x42);
        setop(0x18);
        for (y = 0; y < image->height; y++, where += info->fix.line_length)
                writew(transl_h[cdat[y]&0xF] | transl_l[cdat[y] >> 4], where);
        setmask(oldmask);
        setsr(oldsr);
        setop(oldop);
        setmode(oldmode);
        setindex(oldindex);
}

static void vga_imageblit_expand(struct fb_info *info, const struct fb_image *image)
{
	char __iomem *where = info->screen_base + (image->dx/8) +
		image->dy * info->fix.line_length;
	struct vga16fb_par *par = info->par;
	char *cdat = (char *) image->data;
	char __iomem *dst;
	int x, y;

	switch (info->fix.type) {
	case FB_TYPE_VGA_PLANES:
		if (info->fix.type_aux == FB_AUX_VGA_PLANES_VGA4) {
			if (par->isVGA) {
				setmode(2);
				setop(0);
				setsr(0xf);
				setcolor(image->fg_color);
				selectmask();
				
				setmask(0xff);
				writeb(image->bg_color, where);
				rmb();
				readb(where); /* fill latches */
				setmode(3);
				wmb();
				for (y = 0; y < image->height; y++) {
					dst = where;
					for (x = image->width/8; x--;) 
						writeb(*cdat++, dst++);
					where += info->fix.line_length;
				}
				wmb();
			} else {
				setmode(0);
				setop(0);
				setsr(0xf);
				setcolor(image->bg_color);
				selectmask();
				
				setmask(0xff);
				for (y = 0; y < image->height; y++) {
					dst = where;
					for (x=image->width/8; x--;){
						rmw(dst);
						setcolor(image->fg_color);
						selectmask();
						if (*cdat) {
							setmask(*cdat++);
							rmw(dst++);
						}
					}
					where += info->fix.line_length;
				}
			}
		} else 
			vga_8planes_imageblit(info, image);
		break;
	case FB_TYPE_PACKED_PIXELS:
	default:
		cfb_imageblit(info, image);
		break;
	}
}

static void vga_imageblit_color(struct fb_info *info, const struct fb_image *image)
{
	/*
	 * Draw logo 
	 */
	struct vga16fb_par *par = info->par;
	char __iomem *where =
		info->screen_base + image->dy * info->fix.line_length +
		image->dx/8;
	const char *cdat = image->data;
	char __iomem *dst;
	int x, y;

	switch (info->fix.type) {
	case FB_TYPE_VGA_PLANES:
		if (info->fix.type_aux == FB_AUX_VGA_PLANES_VGA4 &&
		    par->isVGA) {
			setsr(0xf);
			setop(0);
			setmode(0);
			
			for (y = 0; y < image->height; y++) {
				for (x = 0; x < image->width; x++) {
					dst = where + x/8;

					setcolor(*cdat);
					selectmask();
					setmask(1 << (7 - (x % 8)));
					fb_readb(dst);
					fb_writeb(0, dst);

					cdat++;
				}
				where += info->fix.line_length;
			}
		}
		break;
	case FB_TYPE_PACKED_PIXELS:
		cfb_imageblit(info, image);
		break;
	default:
		break;
	}
}
				
static void vga16fb_imageblit(struct fb_info *info, const struct fb_image *image)
{
	if (image->depth == 1)
		vga_imageblit_expand(info, image);
	else
		vga_imageblit_color(info, image);
}

static struct fb_ops vga16fb_ops = {
	.owner		= THIS_MODULE,
	.fb_open        = vga16fb_open,
	.fb_release     = vga16fb_release,
	.fb_check_var	= vga16fb_check_var,
	.fb_set_par	= vga16fb_set_par,
	.fb_setcolreg 	= vga16fb_setcolreg,
	.fb_pan_display = vga16fb_pan_display,
	.fb_blank 	= vga16fb_blank,
	.fb_fillrect	= vga16fb_fillrect,
	.fb_copyarea	= vga16fb_copyarea,
	.fb_imageblit	= vga16fb_imageblit,
};

#ifndef MODULE
static int vga16fb_setup(char *options)
{
	char *this_opt;
	
	if (!options || !*options)
		return 0;
	
	while ((this_opt = strsep(&options, ",")) != NULL) {
		if (!*this_opt) continue;
	}
	return 0;
}
#endif

static int __init vga16fb_probe(struct platform_device *dev)
{
	struct fb_info *info;
	struct vga16fb_par *par;
	int i;
	int ret = 0;

	printk(KERN_DEBUG "vga16fb: initializing\n");
	info = framebuffer_alloc(sizeof(struct vga16fb_par), &dev->dev);

	if (!info) {
		ret = -ENOMEM;
		goto err_fb_alloc;
	}

	/* XXX share VGA_FB_PHYS and I/O region with vgacon and others */
	info->screen_base = (void __iomem *)VGA_MAP_MEM(VGA_FB_PHYS, 0);

	if (!info->screen_base) {
		printk(KERN_ERR "vga16fb: unable to map device\n");
		ret = -ENOMEM;
		goto err_ioremap;
	}

	printk(KERN_INFO "vga16fb: mapped to 0x%p\n", info->screen_base);
	par = info->par;

	par->isVGA = screen_info.orig_video_isVGA;
	par->palette_blanked = 0;
	par->vesa_blanked = 0;

	i = par->isVGA? 6 : 2;
	
	vga16fb_defined.red.length   = i;
	vga16fb_defined.green.length = i;
	vga16fb_defined.blue.length  = i;	

	/* name should not depend on EGA/VGA */
	info->fbops = &vga16fb_ops;
	info->var = vga16fb_defined;
	info->fix = vga16fb_fix;
	/* supports rectangles with widths of multiples of 8 */
	info->pixmap.blit_x = 1 << 7 | 1 << 15 | 1 << 23 | 1 << 31;
	info->flags = FBINFO_FLAG_DEFAULT |
		FBINFO_HWACCEL_YPAN;

	i = (info->var.bits_per_pixel == 8) ? 256 : 16;
	ret = fb_alloc_cmap(&info->cmap, i, 0);
	if (ret) {
		printk(KERN_ERR "vga16fb: unable to allocate colormap\n");
		ret = -ENOMEM;
		goto err_alloc_cmap;
	}

	if (vga16fb_check_var(&info->var, info)) {
		printk(KERN_ERR "vga16fb: unable to validate variable\n");
		ret = -EINVAL;
		goto err_check_var;
	}

	vga16fb_update_fix(info);

	if (register_framebuffer(info) < 0) {
		printk(KERN_ERR "vga16fb: unable to register framebuffer\n");
		ret = -EINVAL;
		goto err_check_var;
	}

	printk(KERN_INFO "fb%d: %s frame buffer device\n",
	       info->node, info->fix.id);
	platform_set_drvdata(dev, info);

	return 0;

 err_check_var:
	fb_dealloc_cmap(&info->cmap);
 err_alloc_cmap:
	iounmap(info->screen_base);
 err_ioremap:
	framebuffer_release(info);
 err_fb_alloc:
	return ret;
}

static int vga16fb_remove(struct platform_device *dev)
{
	struct fb_info *info = platform_get_drvdata(dev);

	if (info) {
		unregister_framebuffer(info);
		iounmap(info->screen_base);
		fb_dealloc_cmap(&info->cmap);
	/* XXX unshare VGA regions */
		framebuffer_release(info);
	}

	return 0;
}

static struct platform_driver vga16fb_driver = {
	.probe = vga16fb_probe,
	.remove = vga16fb_remove,
	.driver = {
		.name = "vga16fb",
	},
};

static struct platform_device *vga16fb_device;

static int __init vga16fb_init(void)
{
	int ret;
#ifndef MODULE
	char *option = NULL;

	if (fb_get_options("vga16fb", &option))
		return -ENODEV;

	vga16fb_setup(option);
#endif
	ret = platform_driver_register(&vga16fb_driver);

	if (!ret) {
		vga16fb_device = platform_device_alloc("vga16fb", 0);

		if (vga16fb_device)
			ret = platform_device_add(vga16fb_device);
		else
			ret = -ENOMEM;

		if (ret) {
			platform_device_put(vga16fb_device);
			platform_driver_unregister(&vga16fb_driver);
		}
	}

	return ret;
}

static void __exit vga16fb_exit(void)
{
	platform_device_unregister(vga16fb_device);
	platform_driver_unregister(&vga16fb_driver);
}

MODULE_DESCRIPTION("Legacy VGA framebuffer device driver");
MODULE_LICENSE("GPL");
module_init(vga16fb_init);
module_exit(vga16fb_exit);


/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-basic-offset: 8
 * End:
 */