[linux-2.6-block.git] / drivers / video / vfb.c

/*
 *  linux/drivers/video/vfb.c -- Virtual frame buffer device
 *
 *      Copyright (C) 2002 James Simmons
 *
 *	Copyright (C) 1997 Geert Uytterhoeven
 *
 *  This file is subject to the terms and conditions of the GNU General Public
 *  License. See the file COPYING in the main directory of this archive for
 *  more details.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/tty.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <asm/uaccess.h>
#include <linux/fb.h>
#include <linux/init.h>

    /*
     *  RAM we reserve for the frame buffer. This defines the maximum screen
     *  size
     *
     *  The default can be overridden if the driver is compiled as a module
     */

#define VIDEOMEMSIZE	(1*1024*1024)	/* 1 MB */

static void *videomemory;
static u_long videomemorysize = VIDEOMEMSIZE;
module_param(videomemorysize, ulong, 0);

static struct fb_var_screeninfo vfb_default __initdata = {
	.xres =		640,
	.yres =		480,
	.xres_virtual =	640,
	.yres_virtual =	480,
	.bits_per_pixel = 8,
	.red =		{ 0, 8, 0 },
      	.green =	{ 0, 8, 0 },
      	.blue =		{ 0, 8, 0 },
      	.activate =	FB_ACTIVATE_TEST,
      	.height =	-1,
      	.width =	-1,
      	.pixclock =	20000,
      	.left_margin =	64,
      	.right_margin =	64,
      	.upper_margin =	32,
      	.lower_margin =	32,
      	.hsync_len =	64,
      	.vsync_len =	2,
      	.vmode =	FB_VMODE_NONINTERLACED,
};

static struct fb_fix_screeninfo vfb_fix __initdata = {
	.id =		"Virtual FB",
	.type =		FB_TYPE_PACKED_PIXELS,
	.visual =	FB_VISUAL_PSEUDOCOLOR,
	.xpanstep =	1,
	.ypanstep =	1,
	.ywrapstep =	1,
	.accel =	FB_ACCEL_NONE,
};

static int vfb_enable __initdata = 0;	/* disabled by default */
module_param(vfb_enable, bool, 0);

static int vfb_check_var(struct fb_var_screeninfo *var,
			 struct fb_info *info);
static int vfb_set_par(struct fb_info *info);
static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
			 u_int transp, struct fb_info *info);
static int vfb_pan_display(struct fb_var_screeninfo *var,
			   struct fb_info *info);
static int vfb_mmap(struct fb_info *info, struct file *file,
		    struct vm_area_struct *vma);

static struct fb_ops vfb_ops = {
	.fb_check_var	= vfb_check_var,
	.fb_set_par	= vfb_set_par,
	.fb_setcolreg	= vfb_setcolreg,
	.fb_pan_display	= vfb_pan_display,
	.fb_fillrect	= cfb_fillrect,
	.fb_copyarea	= cfb_copyarea,
	.fb_imageblit	= cfb_imageblit,
	.fb_cursor	= soft_cursor,
	.fb_mmap	= vfb_mmap,
};

    /*
     *  Internal routines
     */

static u_long get_line_length(int xres_virtual, int bpp)
{
	u_long length;

	length = xres_virtual * bpp;
	length = (length + 31) & ~31;
	length >>= 3;
	return (length);
}

    /*
     *  Setting the video mode has been split into two parts.
     *  First part, xxxfb_check_var, must not write anything
     *  to hardware, it should only verify and adjust var.
     *  This means it doesn't alter par but it does use hardware
     *  data from it to check this var. 
     */

static int vfb_check_var(struct fb_var_screeninfo *var,
			 struct fb_info *info)
{
	u_long line_length;

	/*
	 *  FB_VMODE_CONUPDATE and FB_VMODE_SMOOTH_XPAN are equal!
	 *  as FB_VMODE_SMOOTH_XPAN is only used internally
	 */

	if (var->vmode & FB_VMODE_CONUPDATE) {
		var->vmode |= FB_VMODE_YWRAP;
		var->xoffset = info->var.xoffset;
		var->yoffset = info->var.yoffset;
	}

	/*
	 *  Some very basic checks
	 */
	if (!var->xres)
		var->xres = 1;
	if (!var->yres)
		var->yres = 1;
	if (var->xres > var->xres_virtual)
		var->xres_virtual = var->xres;
	if (var->yres > var->yres_virtual)
		var->yres_virtual = var->yres;
	if (var->bits_per_pixel <= 1)
		var->bits_per_pixel = 1;
	else if (var->bits_per_pixel <= 8)
		var->bits_per_pixel = 8;
	else if (var->bits_per_pixel <= 16)
		var->bits_per_pixel = 16;
	else if (var->bits_per_pixel <= 24)
		var->bits_per_pixel = 24;
	else if (var->bits_per_pixel <= 32)
		var->bits_per_pixel = 32;
	else
		return -EINVAL;

	if (var->xres_virtual < var->xoffset + var->xres)
		var->xres_virtual = var->xoffset + var->xres;
	if (var->yres_virtual < var->yoffset + var->yres)
		var->yres_virtual = var->yoffset + var->yres;

	/*
	 *  Memory limit
	 */
	line_length =
	    get_line_length(var->xres_virtual, var->bits_per_pixel);
	if (line_length * var->yres_virtual > videomemorysize)
		return -ENOMEM;

	/*
	 * Now that we checked it we alter var. The reason being is that the video
	 * mode passed in might not work but slight changes to it might make it 
	 * work. This way we let the user know what is acceptable.
	 */
	switch (var->bits_per_pixel) {
	case 1:
	case 8:
		var->red.offset = 0;
		var->red.length = 8;
		var->green.offset = 0;
		var->green.length = 8;
		var->blue.offset = 0;
		var->blue.length = 8;
		var->transp.offset = 0;
		var->transp.length = 0;
		break;
	case 16:		/* RGBA 5551 */
		if (var->transp.length) {
			var->red.offset = 0;
			var->red.length = 5;
			var->green.offset = 5;
			var->green.length = 5;
			var->blue.offset = 10;
			var->blue.length = 5;
			var->transp.offset = 15;
			var->transp.length = 1;
		} else {	/* RGB 565 */
			var->red.offset = 0;
			var->red.length = 5;
			var->green.offset = 5;
			var->green.length = 6;
			var->blue.offset = 11;
			var->blue.length = 5;
			var->transp.offset = 0;
			var->transp.length = 0;
		}
		break;
	case 24:		/* RGB 888 */
		var->red.offset = 0;
		var->red.length = 8;
		var->green.offset = 8;
		var->green.length = 8;
		var->blue.offset = 16;
		var->blue.length = 8;
		var->transp.offset = 0;
		var->transp.length = 0;
		break;
	case 32:		/* RGBA 8888 */
		var->red.offset = 0;
		var->red.length = 8;
		var->green.offset = 8;
		var->green.length = 8;
		var->blue.offset = 16;
		var->blue.length = 8;
		var->transp.offset = 24;
		var->transp.length = 8;
		break;
	}
	var->red.msb_right = 0;
	var->green.msb_right = 0;
	var->blue.msb_right = 0;
	var->transp.msb_right = 0;

	return 0;
}

/* This routine actually sets the video mode. It's in here where we
 * the hardware state info->par and fix which can be affected by the 
 * change in par. For this driver it doesn't do much. 
 */
static int vfb_set_par(struct fb_info *info)
{
	info->fix.line_length = get_line_length(info->var.xres_virtual,
						info->var.bits_per_pixel);
	return 0;
}

    /*
     *  Set a single color register. The values supplied are already
     *  rounded down to the hardware's capabilities (according to the
     *  entries in the var structure). Return != 0 for invalid regno.
     */

static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
			 u_int transp, struct fb_info *info)
{
	if (regno >= 256)	/* no. of hw registers */
		return 1;
	/*
	 * Program hardware... do anything you want with transp
	 */

	/* grayscale works only partially under directcolor */
	if (info->var.grayscale) {
		/* grayscale = 0.30*R + 0.59*G + 0.11*B */
		red = green = blue =
		    (red * 77 + green * 151 + blue * 28) >> 8;
	}

	/* Directcolor:
	 *   var->{color}.offset contains start of bitfield
	 *   var->{color}.length contains length of bitfield
	 *   {hardwarespecific} contains width of RAMDAC
	 *   cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset)
	 *   RAMDAC[X] is programmed to (red, green, blue)
	 * 
	 * Pseudocolor:
	 *    uses offset = 0 && length = RAMDAC register width.
	 *    var->{color}.offset is 0
	 *    var->{color}.length contains widht of DAC
	 *    cmap is not used
	 *    RAMDAC[X] is programmed to (red, green, blue)
	 * Truecolor:
	 *    does not use DAC. Usually 3 are present.
	 *    var->{color}.offset contains start of bitfield
	 *    var->{color}.length contains length of bitfield
	 *    cmap is programmed to (red << red.offset) | (green << green.offset) |
	 *                      (blue << blue.offset) | (transp << transp.offset)
	 *    RAMDAC does not exist
	 */
#define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
	switch (info->fix.visual) {
	case FB_VISUAL_TRUECOLOR:
	case FB_VISUAL_PSEUDOCOLOR:
		red = CNVT_TOHW(red, info->var.red.length);
		green = CNVT_TOHW(green, info->var.green.length);
		blue = CNVT_TOHW(blue, info->var.blue.length);
		transp = CNVT_TOHW(transp, info->var.transp.length);
		break;
	case FB_VISUAL_DIRECTCOLOR:
		red = CNVT_TOHW(red, 8);	/* expect 8 bit DAC */
		green = CNVT_TOHW(green, 8);
		blue = CNVT_TOHW(blue, 8);
		/* hey, there is bug in transp handling... */
		transp = CNVT_TOHW(transp, 8);
		break;
	}
#undef CNVT_TOHW
	/* Truecolor has hardware independent palette */
	if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
		u32 v;

		if (regno >= 16)
			return 1;

		v = (red << info->var.red.offset) |
		    (green << info->var.green.offset) |
		    (blue << info->var.blue.offset) |
		    (transp << info->var.transp.offset);
		switch (info->var.bits_per_pixel) {
		case 8:
			break;
		case 16:
			((u32 *) (info->pseudo_palette))[regno] = v;
			break;
		case 24:
		case 32:
			((u32 *) (info->pseudo_palette))[regno] = v;
			break;
		}
		return 0;
	}
	return 0;
}

    /*
     *  Pan or Wrap the Display
     *
     *  This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag
     */

static int vfb_pan_display(struct fb_var_screeninfo *var,
			   struct fb_info *info)
{
	if (var->vmode & FB_VMODE_YWRAP) {
		if (var->yoffset < 0
		    || var->yoffset >= info->var.yres_virtual
		    || var->xoffset)
			return -EINVAL;
	} else {
		if (var->xoffset + var->xres > info->var.xres_virtual ||
		    var->yoffset + var->yres > info->var.yres_virtual)
			return -EINVAL;
	}
	info->var.xoffset = var->xoffset;
	info->var.yoffset = var->yoffset;
	if (var->vmode & FB_VMODE_YWRAP)
		info->var.vmode |= FB_VMODE_YWRAP;
	else
		info->var.vmode &= ~FB_VMODE_YWRAP;
	return 0;
}

    /*
     *  Most drivers don't need their own mmap function 
     */

static int vfb_mmap(struct fb_info *info, struct file *file,
		    struct vm_area_struct *vma)
{
	return -EINVAL;
}

#ifndef MODULE
static int __init vfb_setup(char *options)
{
	char *this_opt;

	vfb_enable = 1;

	if (!options || !*options)
		return 1;

	while ((this_opt = strsep(&options, ",")) != NULL) {
		if (!*this_opt)
			continue;
		if (!strncmp(this_opt, "disable", 7))
			vfb_enable = 0;
	}
	return 1;
}
#endif  /*  MODULE  */

    /*
     *  Initialisation
     */

static void vfb_platform_release(struct device *device)
{
	// This is called when the reference count goes to zero.
}

static int __init vfb_probe(struct device *device)
{
	struct platform_device *dev = to_platform_device(device);
	struct fb_info *info;
	int retval = -ENOMEM;

	/*
	 * For real video cards we use ioremap.
	 */
	if (!(videomemory = vmalloc(videomemorysize)))
		return retval;

	/*
	 * VFB must clear memory to prevent kernel info
	 * leakage into userspace
	 * VGA-based drivers MUST NOT clear memory if
	 * they want to be able to take over vgacon
	 */
	memset(videomemory, 0, videomemorysize);

	info = framebuffer_alloc(sizeof(u32) * 256, &dev->dev);
	if (!info)
		goto err;

	info->screen_base = (char __iomem *)videomemory;
	info->fbops = &vfb_ops;

	retval = fb_find_mode(&info->var, info, NULL,
			      NULL, 0, NULL, 8);

	if (!retval || (retval == 4))
		info->var = vfb_default;
	info->fix = vfb_fix;
	info->pseudo_palette = info->par;
	info->par = NULL;
	info->flags = FBINFO_FLAG_DEFAULT;

	retval = fb_alloc_cmap(&info->cmap, 256, 0);
	if (retval < 0)
		goto err1;

	retval = register_framebuffer(info);
	if (retval < 0)
		goto err2;
	dev_set_drvdata(&dev->dev, info);

	printk(KERN_INFO
	       "fb%d: Virtual frame buffer device, using %ldK of video memory\n",
	       info->node, videomemorysize >> 10);
	return 0;
err2:
	fb_dealloc_cmap(&info->cmap);
err1:
	framebuffer_release(info);
err:
	vfree(videomemory);
	return retval;
}

static int vfb_remove(struct device *device)
{
	struct fb_info *info = dev_get_drvdata(device);

	if (info) {
		unregister_framebuffer(info);
		vfree(videomemory);
		framebuffer_release(info);
	}
	return 0;
}

static struct device_driver vfb_driver = {
	.name	= "vfb",
	.bus	= &platform_bus_type,
	.probe	= vfb_probe,
	.remove = vfb_remove,
};

static struct platform_device vfb_device = {
	.name	= "vfb",
	.id	= 0,
	.dev	= {
		.release = vfb_platform_release,
	}
};

static int __init vfb_init(void)
{
	int ret = 0;

#ifndef MODULE
	char *option = NULL;

	if (fb_get_options("vfb", &option))
		return -ENODEV;
	vfb_setup(option);
#endif

	if (!vfb_enable)
		return -ENXIO;

	ret = driver_register(&vfb_driver);

	if (!ret) {
		ret = platform_device_register(&vfb_device);
		if (ret)
			driver_unregister(&vfb_driver);
	}
	return ret;
}

module_init(vfb_init);

#ifdef MODULE
static void __exit vfb_exit(void)
{
	platform_device_unregister(&vfb_device);
	driver_unregister(&vfb_driver);
}

module_exit(vfb_exit);

MODULE_LICENSE("GPL");
#endif				/* MODULE */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/drivers/video/vfb.c -- Virtual frame buffer device
	3	*
	4	* Copyright (C) 2002 James Simmons
	5	*
	6	* Copyright (C) 1997 Geert Uytterhoeven
	7	*
	8	* This file is subject to the terms and conditions of the GNU General Public
	9	* License. See the file COPYING in the main directory of this archive for
	10	* more details.
	11	*/
	12
	13	#include <linux/module.h>
	14	#include <linux/kernel.h>
	15	#include <linux/errno.h>
	16	#include <linux/string.h>
	17	#include <linux/mm.h>
	18	#include <linux/tty.h>
	19	#include <linux/slab.h>
	20	#include <linux/vmalloc.h>
	21	#include <linux/delay.h>
	22	#include <linux/interrupt.h>
	23	#include <asm/uaccess.h>
	24	#include <linux/fb.h>
	25	#include <linux/init.h>
	26
	27	/*
	28	* RAM we reserve for the frame buffer. This defines the maximum screen
	29	* size
	30	*
	31	* The default can be overridden if the driver is compiled as a module
	32	*/
	33
	34	#define VIDEOMEMSIZE (110241024) /* 1 MB */
	35
	36	static void *videomemory;
	37	static u_long videomemorysize = VIDEOMEMSIZE;
	38	module_param(videomemorysize, ulong, 0);
	39
	40	static struct fb_var_screeninfo vfb_default __initdata = {
	41	.xres = 640,
	42	.yres = 480,
	43	.xres_virtual = 640,
	44	.yres_virtual = 480,
	45	.bits_per_pixel = 8,
	46	.red = { 0, 8, 0 },
	47	.green = { 0, 8, 0 },
	48	.blue = { 0, 8, 0 },
	49	.activate = FB_ACTIVATE_TEST,
	50	.height = -1,
	51	.width = -1,
	52	.pixclock = 20000,
	53	.left_margin = 64,
	54	.right_margin = 64,
	55	.upper_margin = 32,
	56	.lower_margin = 32,
	57	.hsync_len = 64,
	58	.vsync_len = 2,
	59	.vmode = FB_VMODE_NONINTERLACED,
	60	};
	61
	62	static struct fb_fix_screeninfo vfb_fix __initdata = {
	63	.id = "Virtual FB",
	64	.type = FB_TYPE_PACKED_PIXELS,
65	.visual = FB_VISUAL_PSEUDOCOLOR,
66	.xpanstep = 1,
67	.ypanstep = 1,
68	.ywrapstep = 1,
69	.accel = FB_ACCEL_NONE,
70	};
71
72	static int vfb_enable __initdata = 0; /* disabled by default */
73	module_param(vfb_enable, bool, 0);
74
75	static int vfb_check_var(struct fb_var_screeninfo *var,
76	struct fb_info *info);
77	static int vfb_set_par(struct fb_info *info);
78	static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
79	u_int transp, struct fb_info *info);
80	static int vfb_pan_display(struct fb_var_screeninfo *var,
81	struct fb_info *info);
82	static int vfb_mmap(struct fb_info info, struct file file,
83	struct vm_area_struct *vma);
84
85	static struct fb_ops vfb_ops = {
86	.fb_check_var = vfb_check_var,
87	.fb_set_par = vfb_set_par,
88	.fb_setcolreg = vfb_setcolreg,
89	.fb_pan_display = vfb_pan_display,
90	.fb_fillrect = cfb_fillrect,
91	.fb_copyarea = cfb_copyarea,
92	.fb_imageblit = cfb_imageblit,
93	.fb_cursor = soft_cursor,
94	.fb_mmap = vfb_mmap,
95	};
96
97	/*
98	* Internal routines
99	*/
100
101	static u_long get_line_length(int xres_virtual, int bpp)
102	{
103	u_long length;
104
105	length = xres_virtual * bpp;
106	length = (length + 31) & ~31;
107	length >>= 3;
108	return (length);
109	}
110
111	/*
112	* Setting the video mode has been split into two parts.
113	* First part, xxxfb_check_var, must not write anything
114	* to hardware, it should only verify and adjust var.
115	* This means it doesn't alter par but it does use hardware
116	* data from it to check this var.
117	*/
118
119	static int vfb_check_var(struct fb_var_screeninfo *var,
120	struct fb_info *info)
121	{
122	u_long line_length;
123
124	/*
125	* FB_VMODE_CONUPDATE and FB_VMODE_SMOOTH_XPAN are equal!
126	* as FB_VMODE_SMOOTH_XPAN is only used internally
127	*/
128
129	if (var->vmode & FB_VMODE_CONUPDATE) {
130	var->vmode \|= FB_VMODE_YWRAP;
131	var->xoffset = info->var.xoffset;
132	var->yoffset = info->var.yoffset;
133	}
134
135	/*
136	* Some very basic checks
137	*/
138	if (!var->xres)
139	var->xres = 1;
140	if (!var->yres)
141	var->yres = 1;
142	if (var->xres > var->xres_virtual)
143	var->xres_virtual = var->xres;
144	if (var->yres > var->yres_virtual)
145	var->yres_virtual = var->yres;
146	if (var->bits_per_pixel <= 1)
147	var->bits_per_pixel = 1;
148	else if (var->bits_per_pixel <= 8)
149	var->bits_per_pixel = 8;
150	else if (var->bits_per_pixel <= 16)
151	var->bits_per_pixel = 16;
152	else if (var->bits_per_pixel <= 24)
153	var->bits_per_pixel = 24;
154	else if (var->bits_per_pixel <= 32)
155	var->bits_per_pixel = 32;
156	else
157	return -EINVAL;
158
159	if (var->xres_virtual < var->xoffset + var->xres)
160	var->xres_virtual = var->xoffset + var->xres;
161	if (var->yres_virtual < var->yoffset + var->yres)
162	var->yres_virtual = var->yoffset + var->yres;
163
164	/*
165	* Memory limit
166	*/
167	line_length =
168	get_line_length(var->xres_virtual, var->bits_per_pixel);
169	if (line_length * var->yres_virtual > videomemorysize)
170	return -ENOMEM;
171
172	/*
173	* Now that we checked it we alter var. The reason being is that the video
174	* mode passed in might not work but slight changes to it might make it
175	* work. This way we let the user know what is acceptable.
176	*/
177	switch (var->bits_per_pixel) {
178	case 1:
179	case 8:
180	var->red.offset = 0;
181	var->red.length = 8;
182	var->green.offset = 0;
183	var->green.length = 8;
184	var->blue.offset = 0;
185	var->blue.length = 8;
186	var->transp.offset = 0;
187	var->transp.length = 0;
188	break;
189	case 16: /* RGBA 5551 */
190	if (var->transp.length) {
191	var->red.offset = 0;
192	var->red.length = 5;
193	var->green.offset = 5;
194	var->green.length = 5;
195	var->blue.offset = 10;
196	var->blue.length = 5;
197	var->transp.offset = 15;
198	var->transp.length = 1;
199	} else { /* RGB 565 */
200	var->red.offset = 0;
201	var->red.length = 5;
202	var->green.offset = 5;
203	var->green.length = 6;
204	var->blue.offset = 11;
205	var->blue.length = 5;
206	var->transp.offset = 0;
207	var->transp.length = 0;
208	}
209	break;
210	case 24: /* RGB 888 */
211	var->red.offset = 0;
212	var->red.length = 8;
213	var->green.offset = 8;
214	var->green.length = 8;
215	var->blue.offset = 16;
216	var->blue.length = 8;
217	var->transp.offset = 0;
218	var->transp.length = 0;
219	break;
220	case 32: /* RGBA 8888 */
221	var->red.offset = 0;
222	var->red.length = 8;
223	var->green.offset = 8;
224	var->green.length = 8;
225	var->blue.offset = 16;
226	var->blue.length = 8;
227	var->transp.offset = 24;
228	var->transp.length = 8;
229	break;
230	}
231	var->red.msb_right = 0;
232	var->green.msb_right = 0;
233	var->blue.msb_right = 0;
234	var->transp.msb_right = 0;
235
236	return 0;
237	}
238
239	/* This routine actually sets the video mode. It's in here where we
240	* the hardware state info->par and fix which can be affected by the
241	* change in par. For this driver it doesn't do much.
242	*/
243	static int vfb_set_par(struct fb_info *info)
244	{
245	info->fix.line_length = get_line_length(info->var.xres_virtual,
246	info->var.bits_per_pixel);
247	return 0;
248	}
249
250	/*
251	* Set a single color register. The values supplied are already
252	* rounded down to the hardware's capabilities (according to the
253	* entries in the var structure). Return != 0 for invalid regno.
254	*/
255
256	static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
257	u_int transp, struct fb_info *info)
258	{
259	if (regno >= 256) /* no. of hw registers */
260	return 1;
261	/*
262	* Program hardware... do anything you want with transp
263	*/
264
265	/* grayscale works only partially under directcolor */
266	if (info->var.grayscale) {
267	/* grayscale = 0.30R + 0.59G + 0.11B /
268	red = green = blue =
269	(red * 77 + green * 151 + blue * 28) >> 8;
270	}
271
272	/* Directcolor:
273	* var->{color}.offset contains start of bitfield
274	* var->{color}.length contains length of bitfield
275	* {hardwarespecific} contains width of RAMDAC
276	* cmap[X] is programmed to (X << red.offset) \| (X << green.offset) \| (X << blue.offset)
277	* RAMDAC[X] is programmed to (red, green, blue)
278	*
279	* Pseudocolor:
280	* uses offset = 0 && length = RAMDAC register width.
281	* var->{color}.offset is 0
282	* var->{color}.length contains widht of DAC
283	* cmap is not used
284	* RAMDAC[X] is programmed to (red, green, blue)
285	* Truecolor:
286	* does not use DAC. Usually 3 are present.
287	* var->{color}.offset contains start of bitfield
288	* var->{color}.length contains length of bitfield
289	* cmap is programmed to (red << red.offset) \| (green << green.offset) \|
290	* (blue << blue.offset) \| (transp << transp.offset)
291	* RAMDAC does not exist
292	*/
293	#define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
294	switch (info->fix.visual) {
295	case FB_VISUAL_TRUECOLOR:
296	case FB_VISUAL_PSEUDOCOLOR:
297	red = CNVT_TOHW(red, info->var.red.length);
298	green = CNVT_TOHW(green, info->var.green.length);
299	blue = CNVT_TOHW(blue, info->var.blue.length);
300	transp = CNVT_TOHW(transp, info->var.transp.length);
301	break;
302	case FB_VISUAL_DIRECTCOLOR:
303	red = CNVT_TOHW(red, 8); /* expect 8 bit DAC */
304	green = CNVT_TOHW(green, 8);
305	blue = CNVT_TOHW(blue, 8);
306	/* hey, there is bug in transp handling... */
307	transp = CNVT_TOHW(transp, 8);
308	break;
309	}
310	#undef CNVT_TOHW
311	/* Truecolor has hardware independent palette */
312	if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
313	u32 v;
314
315	if (regno >= 16)
316	return 1;
317
318	v = (red << info->var.red.offset) \|
319	(green << info->var.green.offset) \|
320	(blue << info->var.blue.offset) \|
321	(transp << info->var.transp.offset);
322	switch (info->var.bits_per_pixel) {
323	case 8:
324	break;
325	case 16:
326	((u32 *) (info->pseudo_palette))[regno] = v;
327	break;
328	case 24:
329	case 32:
330	((u32 *) (info->pseudo_palette))[regno] = v;
331	break;
332	}
333	return 0;
334	}
335	return 0;
336	}
337
338	/*
339	* Pan or Wrap the Display
340	*
341	* This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag
342	*/
343
344	static int vfb_pan_display(struct fb_var_screeninfo *var,
345	struct fb_info *info)
346	{
347	if (var->vmode & FB_VMODE_YWRAP) {
348	if (var->yoffset < 0
349	\|\| var->yoffset >= info->var.yres_virtual
350	\|\| var->xoffset)
351	return -EINVAL;
352	} else {
353	if (var->xoffset + var->xres > info->var.xres_virtual \|\|
354	var->yoffset + var->yres > info->var.yres_virtual)
355	return -EINVAL;
356	}
357	info->var.xoffset = var->xoffset;
358	info->var.yoffset = var->yoffset;
359	if (var->vmode & FB_VMODE_YWRAP)
360	info->var.vmode \|= FB_VMODE_YWRAP;
361	else
362	info->var.vmode &= ~FB_VMODE_YWRAP;
363	return 0;
364	}
365
366	/*
367	* Most drivers don't need their own mmap function
368	*/
369
370	static int vfb_mmap(struct fb_info info, struct file file,
371	struct vm_area_struct *vma)
372	{
373	return -EINVAL;
374	}
375
376	#ifndef MODULE
377	static int __init vfb_setup(char *options)
378	{
379	char *this_opt;
380
381	vfb_enable = 1;
382
383	if (!options \|\| !*options)
384	return 1;
385
386	while ((this_opt = strsep(&options, ",")) != NULL) {
387	if (!*this_opt)
388	continue;
389	if (!strncmp(this_opt, "disable", 7))
390	vfb_enable = 0;
391	}
392	return 1;
393	}
394	#endif /* MODULE */
395
396	/*
397	* Initialisation
398	*/
399
400	static void vfb_platform_release(struct device *device)
401	{
402	// This is called when the reference count goes to zero.
403	}
404
405	static int __init vfb_probe(struct device *device)
406	{
407	struct platform_device *dev = to_platform_device(device);
408	struct fb_info *info;
409	int retval = -ENOMEM;
410
411	/*
412	* For real video cards we use ioremap.
413	*/
414	if (!(videomemory = vmalloc(videomemorysize)))
415	return retval;
416
417	/*
418	* VFB must clear memory to prevent kernel info
419	* leakage into userspace
420	* VGA-based drivers MUST NOT clear memory if
421	* they want to be able to take over vgacon
422	*/
423	memset(videomemory, 0, videomemorysize);
424
425	info = framebuffer_alloc(sizeof(u32) * 256, &dev->dev);
426	if (!info)
427	goto err;
428
429	info->screen_base = (char __iomem *)videomemory;
430	info->fbops = &vfb_ops;
431
432	retval = fb_find_mode(&info->var, info, NULL,
433	NULL, 0, NULL, 8);
434
435	if (!retval \|\| (retval == 4))
436	info->var = vfb_default;
437	info->fix = vfb_fix;
438	info->pseudo_palette = info->par;
439	info->par = NULL;
440	info->flags = FBINFO_FLAG_DEFAULT;
441
442	retval = fb_alloc_cmap(&info->cmap, 256, 0);
443	if (retval < 0)
444	goto err1;
445
446	retval = register_framebuffer(info);
447	if (retval < 0)
448	goto err2;
449	dev_set_drvdata(&dev->dev, info);
450
451	printk(KERN_INFO
452	"fb%d: Virtual frame buffer device, using %ldK of video memory\n",
453	info->node, videomemorysize >> 10);
454	return 0;
455	err2:
456	fb_dealloc_cmap(&info->cmap);
457	err1:
458	framebuffer_release(info);
459	err:
460	vfree(videomemory);
461	return retval;
462	}
463
464	static int vfb_remove(struct device *device)
465	{
466	struct fb_info *info = dev_get_drvdata(device);
467
468	if (info) {
469	unregister_framebuffer(info);
470	vfree(videomemory);
471	framebuffer_release(info);
472	}
473	return 0;
474	}
475
476	static struct device_driver vfb_driver = {
477	.name = "vfb",
478	.bus = &platform_bus_type,
479	.probe = vfb_probe,
480	.remove = vfb_remove,
481	};
482
483	static struct platform_device vfb_device = {
484	.name = "vfb",
485	.id = 0,
486	.dev = {
487	.release = vfb_platform_release,
488	}
489	};
490
491	static int __init vfb_init(void)
492	{
493	int ret = 0;
494
495	#ifndef MODULE
496	char *option = NULL;
497
498	if (fb_get_options("vfb", &option))
499	return -ENODEV;
500	vfb_setup(option);
501	#endif
502
503	if (!vfb_enable)
504	return -ENXIO;
505
506	ret = driver_register(&vfb_driver);
507
508	if (!ret) {
509	ret = platform_device_register(&vfb_device);
510	if (ret)
511	driver_unregister(&vfb_driver);
512	}
513	return ret;
514	}
515
516	module_init(vfb_init);
517
518	#ifdef MODULE
519	static void __exit vfb_exit(void)
520	{
521	platform_device_unregister(&vfb_device);
522	driver_unregister(&vfb_driver);
523	}
524
525	module_exit(vfb_exit);
526
527	MODULE_LICENSE("GPL");
528	#endif /* MODULE */