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/slab.h>
19#include <linux/vmalloc.h>
20#include <linux/delay.h>
21#include <linux/interrupt.h>
22#include <linux/platform_device.h>
23
24#include <asm/uaccess.h>
25#include <linux/fb.h>
26#include <linux/init.h>
27
28    /*
29     *  RAM we reserve for the frame buffer. This defines the maximum screen
30     *  size
31     *
32     *  The default can be overridden if the driver is compiled as a module
33     */
34
35#define VIDEOMEMSIZE	(1*1024*1024)	/* 1 MB */
36
37static void *videomemory;
38static u_long videomemorysize = VIDEOMEMSIZE;
39module_param(videomemorysize, ulong, 0);
40
41static struct fb_var_screeninfo vfb_default __initdata = {
42	.xres =		640,
43	.yres =		480,
44	.xres_virtual =	640,
45	.yres_virtual =	480,
46	.bits_per_pixel = 8,
47	.red =		{ 0, 8, 0 },
48      	.green =	{ 0, 8, 0 },
49      	.blue =		{ 0, 8, 0 },
50      	.activate =	FB_ACTIVATE_TEST,
51      	.height =	-1,
52      	.width =	-1,
53      	.pixclock =	20000,
54      	.left_margin =	64,
55      	.right_margin =	64,
56      	.upper_margin =	32,
57      	.lower_margin =	32,
58      	.hsync_len =	64,
59      	.vsync_len =	2,
60      	.vmode =	FB_VMODE_NONINTERLACED,
61};
62
63static struct fb_fix_screeninfo vfb_fix __initdata = {
64	.id =		"Virtual FB",
65	.type =		FB_TYPE_PACKED_PIXELS,
66	.visual =	FB_VISUAL_PSEUDOCOLOR,
67	.xpanstep =	1,
68	.ypanstep =	1,
69	.ywrapstep =	1,
70	.accel =	FB_ACCEL_NONE,
71};
72
73static int vfb_enable __initdata = 0;	/* disabled by default */
74module_param(vfb_enable, bool, 0);
75
76static int vfb_check_var(struct fb_var_screeninfo *var,
77			 struct fb_info *info);
78static int vfb_set_par(struct fb_info *info);
79static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
80			 u_int transp, struct fb_info *info);
81static int vfb_pan_display(struct fb_var_screeninfo *var,
82			   struct fb_info *info);
83static int vfb_mmap(struct fb_info *info,
84		    struct vm_area_struct *vma);
85
86static struct fb_ops vfb_ops = {
87	.fb_read        = fb_sys_read,
88	.fb_write       = fb_sys_write,
89	.fb_check_var	= vfb_check_var,
90	.fb_set_par	= vfb_set_par,
91	.fb_setcolreg	= vfb_setcolreg,
92	.fb_pan_display	= vfb_pan_display,
93	.fb_fillrect	= sys_fillrect,
94	.fb_copyarea	= sys_copyarea,
95	.fb_imageblit	= sys_imageblit,
96	.fb_mmap	= vfb_mmap,
97};
98
99    /*
100     *  Internal routines
101     */
102
103static u_long get_line_length(int xres_virtual, int bpp)
104{
105	u_long length;
106
107	length = xres_virtual * bpp;
108	length = (length + 31) & ~31;
109	length >>= 3;
110	return (length);
111}
112
113    /*
114     *  Setting the video mode has been split into two parts.
115     *  First part, xxxfb_check_var, must not write anything
116     *  to hardware, it should only verify and adjust var.
117     *  This means it doesn't alter par but it does use hardware
118     *  data from it to check this var.
119     */
120
121static int vfb_check_var(struct fb_var_screeninfo *var,
122			 struct fb_info *info)
123{
124	u_long line_length;
125
126	/*
127	 *  FB_VMODE_CONUPDATE and FB_VMODE_SMOOTH_XPAN are equal!
128	 *  as FB_VMODE_SMOOTH_XPAN is only used internally
129	 */
130
131	if (var->vmode & FB_VMODE_CONUPDATE) {
132		var->vmode |= FB_VMODE_YWRAP;
133		var->xoffset = info->var.xoffset;
134		var->yoffset = info->var.yoffset;
135	}
136
137	/*
138	 *  Some very basic checks
139	 */
140	if (!var->xres)
141		var->xres = 1;
142	if (!var->yres)
143		var->yres = 1;
144	if (var->xres > var->xres_virtual)
145		var->xres_virtual = var->xres;
146	if (var->yres > var->yres_virtual)
147		var->yres_virtual = var->yres;
148	if (var->bits_per_pixel <= 1)
149		var->bits_per_pixel = 1;
150	else if (var->bits_per_pixel <= 8)
151		var->bits_per_pixel = 8;
152	else if (var->bits_per_pixel <= 16)
153		var->bits_per_pixel = 16;
154	else if (var->bits_per_pixel <= 24)
155		var->bits_per_pixel = 24;
156	else if (var->bits_per_pixel <= 32)
157		var->bits_per_pixel = 32;
158	else
159		return -EINVAL;
160
161	if (var->xres_virtual < var->xoffset + var->xres)
162		var->xres_virtual = var->xoffset + var->xres;
163	if (var->yres_virtual < var->yoffset + var->yres)
164		var->yres_virtual = var->yoffset + var->yres;
165
166	/*
167	 *  Memory limit
168	 */
169	line_length =
170	    get_line_length(var->xres_virtual, var->bits_per_pixel);
171	if (line_length * var->yres_virtual > videomemorysize)
172		return -ENOMEM;
173
174	/*
175	 * Now that we checked it we alter var. The reason being is that the video
176	 * mode passed in might not work but slight changes to it might make it
177	 * work. This way we let the user know what is acceptable.
178	 */
179	switch (var->bits_per_pixel) {
180	case 1:
181	case 8:
182		var->red.offset = 0;
183		var->red.length = 8;
184		var->green.offset = 0;
185		var->green.length = 8;
186		var->blue.offset = 0;
187		var->blue.length = 8;
188		var->transp.offset = 0;
189		var->transp.length = 0;
190		break;
191	case 16:		/* RGBA 5551 */
192		if (var->transp.length) {
193			var->red.offset = 0;
194			var->red.length = 5;
195			var->green.offset = 5;
196			var->green.length = 5;
197			var->blue.offset = 10;
198			var->blue.length = 5;
199			var->transp.offset = 15;
200			var->transp.length = 1;
201		} else {	/* RGB 565 */
202			var->red.offset = 0;
203			var->red.length = 5;
204			var->green.offset = 5;
205			var->green.length = 6;
206			var->blue.offset = 11;
207			var->blue.length = 5;
208			var->transp.offset = 0;
209			var->transp.length = 0;
210		}
211		break;
212	case 24:		/* RGB 888 */
213		var->red.offset = 0;
214		var->red.length = 8;
215		var->green.offset = 8;
216		var->green.length = 8;
217		var->blue.offset = 16;
218		var->blue.length = 8;
219		var->transp.offset = 0;
220		var->transp.length = 0;
221		break;
222	case 32:		/* RGBA 8888 */
223		var->red.offset = 0;
224		var->red.length = 8;
225		var->green.offset = 8;
226		var->green.length = 8;
227		var->blue.offset = 16;
228		var->blue.length = 8;
229		var->transp.offset = 24;
230		var->transp.length = 8;
231		break;
232	}
233	var->red.msb_right = 0;
234	var->green.msb_right = 0;
235	var->blue.msb_right = 0;
236	var->transp.msb_right = 0;
237
238	return 0;
239}
240
241/* This routine actually sets the video mode. It's in here where we
242 * the hardware state info->par and fix which can be affected by the
243 * change in par. For this driver it doesn't do much.
244 */
245static int vfb_set_par(struct fb_info *info)
246{
247	info->fix.line_length = get_line_length(info->var.xres_virtual,
248						info->var.bits_per_pixel);
249	return 0;
250}
251
252    /*
253     *  Set a single color register. The values supplied are already
254     *  rounded down to the hardware's capabilities (according to the
255     *  entries in the var structure). Return != 0 for invalid regno.
256     */
257
258static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
259			 u_int transp, struct fb_info *info)
260{
261	if (regno >= 256)	/* no. of hw registers */
262		return 1;
263	/*
264	 * Program hardware... do anything you want with transp
265	 */
266
267	/* grayscale works only partially under directcolor */
268	if (info->var.grayscale) {
269		/* grayscale = 0.30*R + 0.59*G + 0.11*B */
270		red = green = blue =
271		    (red * 77 + green * 151 + blue * 28) >> 8;
272	}
273
274	/* Directcolor:
275	 *   var->{color}.offset contains start of bitfield
276	 *   var->{color}.length contains length of bitfield
277	 *   {hardwarespecific} contains width of RAMDAC
278	 *   cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset)
279	 *   RAMDAC[X] is programmed to (red, green, blue)
280	 *
281	 * Pseudocolor:
282	 *    uses offset = 0 && length = RAMDAC register width.
283	 *    var->{color}.offset is 0
284	 *    var->{color}.length contains widht of DAC
285	 *    cmap is not used
286	 *    RAMDAC[X] is programmed to (red, green, blue)
287	 * Truecolor:
288	 *    does not use DAC. Usually 3 are present.
289	 *    var->{color}.offset contains start of bitfield
290	 *    var->{color}.length contains length of bitfield
291	 *    cmap is programmed to (red << red.offset) | (green << green.offset) |
292	 *                      (blue << blue.offset) | (transp << transp.offset)
293	 *    RAMDAC does not exist
294	 */
295#define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
296	switch (info->fix.visual) {
297	case FB_VISUAL_TRUECOLOR:
298	case FB_VISUAL_PSEUDOCOLOR:
299		red = CNVT_TOHW(red, info->var.red.length);
300		green = CNVT_TOHW(green, info->var.green.length);
301		blue = CNVT_TOHW(blue, info->var.blue.length);
302		transp = CNVT_TOHW(transp, info->var.transp.length);
303		break;
304	case FB_VISUAL_DIRECTCOLOR:
305		red = CNVT_TOHW(red, 8);	/* expect 8 bit DAC */
306		green = CNVT_TOHW(green, 8);
307		blue = CNVT_TOHW(blue, 8);
308		/* hey, there is bug in transp handling... */
309		transp = CNVT_TOHW(transp, 8);
310		break;
311	}
312#undef CNVT_TOHW
313	/* Truecolor has hardware independent palette */
314	if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
315		u32 v;
316
317		if (regno >= 16)
318			return 1;
319
320		v = (red << info->var.red.offset) |
321		    (green << info->var.green.offset) |
322		    (blue << info->var.blue.offset) |
323		    (transp << info->var.transp.offset);
324		switch (info->var.bits_per_pixel) {
325		case 8:
326			break;
327		case 16:
328			((u32 *) (info->pseudo_palette))[regno] = v;
329			break;
330		case 24:
331		case 32:
332			((u32 *) (info->pseudo_palette))[regno] = v;
333			break;
334		}
335		return 0;
336	}
337	return 0;
338}
339
340    /*
341     *  Pan or Wrap the Display
342     *
343     *  This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag
344     */
345
346static int vfb_pan_display(struct fb_var_screeninfo *var,
347			   struct fb_info *info)
348{
349	if (var->vmode & FB_VMODE_YWRAP) {
350		if (var->yoffset < 0
351		    || var->yoffset >= info->var.yres_virtual
352		    || var->xoffset)
353			return -EINVAL;
354	} else {
355		if (var->xoffset + var->xres > info->var.xres_virtual ||
356		    var->yoffset + var->yres > info->var.yres_virtual)
357			return -EINVAL;
358	}
359	info->var.xoffset = var->xoffset;
360	info->var.yoffset = var->yoffset;
361	if (var->vmode & FB_VMODE_YWRAP)
362		info->var.vmode |= FB_VMODE_YWRAP;
363	else
364		info->var.vmode &= ~FB_VMODE_YWRAP;
365	return 0;
366}
367
368    /*
369     *  Most drivers don't need their own mmap function
370     */
371
372static int vfb_mmap(struct fb_info *info,
373		    struct vm_area_struct *vma)
374{
375	return -EINVAL;
376}
377
378#ifndef MODULE
379static int __init vfb_setup(char *options)
380{
381	char *this_opt;
382
383	vfb_enable = 1;
384
385	if (!options || !*options)
386		return 1;
387
388	while ((this_opt = strsep(&options, ",")) != NULL) {
389		if (!*this_opt)
390			continue;
391		if (!strncmp(this_opt, "disable", 7))
392			vfb_enable = 0;
393	}
394	return 1;
395}
396#endif  /*  MODULE  */
397
398    /*
399     *  Initialisation
400     */
401
402static int __init vfb_probe(struct platform_device *dev)
403{
404	struct fb_info *info;
405	int retval = -ENOMEM;
406
407	/*
408	 * For real video cards we use ioremap.
409	 */
410	if (!(videomemory = vmalloc(videomemorysize)))
411		return retval;
412
413	/*
414	 * VFB must clear memory to prevent kernel info
415	 * leakage into userspace
416	 * VGA-based drivers MUST NOT clear memory if
417	 * they want to be able to take over vgacon
418	 */
419	memset(videomemory, 0, videomemorysize);
420
421	info = framebuffer_alloc(sizeof(u32) * 256, &dev->dev);
422	if (!info)
423		goto err;
424
425	info->screen_base = (char __iomem *)videomemory;
426	info->fbops = &vfb_ops;
427
428	retval = fb_find_mode(&info->var, info, NULL,
429			      NULL, 0, NULL, 8);
430
431	if (!retval || (retval == 4))
432		info->var = vfb_default;
433	info->fix = vfb_fix;
434	info->pseudo_palette = info->par;
435	info->par = NULL;
436	info->flags = FBINFO_FLAG_DEFAULT;
437
438	retval = fb_alloc_cmap(&info->cmap, 256, 0);
439	if (retval < 0)
440		goto err1;
441
442	retval = register_framebuffer(info);
443	if (retval < 0)
444		goto err2;
445	platform_set_drvdata(dev, info);
446
447	printk(KERN_INFO
448	       "fb%d: Virtual frame buffer device, using %ldK of video memory\n",
449	       info->node, videomemorysize >> 10);
450	return 0;
451err2:
452	fb_dealloc_cmap(&info->cmap);
453err1:
454	framebuffer_release(info);
455err:
456	vfree(videomemory);
457	return retval;
458}
459
460static int vfb_remove(struct platform_device *dev)
461{
462	struct fb_info *info = platform_get_drvdata(dev);
463
464	if (info) {
465		unregister_framebuffer(info);
466		vfree(videomemory);
467		framebuffer_release(info);
468	}
469	return 0;
470}
471
472static struct platform_driver vfb_driver = {
473	.probe	= vfb_probe,
474	.remove = vfb_remove,
475	.driver = {
476		.name	= "vfb",
477	},
478};
479
480static struct platform_device *vfb_device;
481
482static int __init vfb_init(void)
483{
484	int ret = 0;
485
486#ifndef MODULE
487	char *option = NULL;
488
489	if (fb_get_options("vfb", &option))
490		return -ENODEV;
491	vfb_setup(option);
492#endif
493
494	if (!vfb_enable)
495		return -ENXIO;
496
497	ret = platform_driver_register(&vfb_driver);
498
499	if (!ret) {
500		vfb_device = platform_device_alloc("vfb", 0);
501
502		if (vfb_device)
503			ret = platform_device_add(vfb_device);
504		else
505			ret = -ENOMEM;
506
507		if (ret) {
508			platform_device_put(vfb_device);
509			platform_driver_unregister(&vfb_driver);
510		}
511	}
512
513	return ret;
514}
515
516module_init(vfb_init);
517
518#ifdef MODULE
519static void __exit vfb_exit(void)
520{
521	platform_device_unregister(vfb_device);
522	platform_driver_unregister(&vfb_driver);
523}
524
525module_exit(vfb_exit);
526
527MODULE_LICENSE("GPL");
528#endif				/* MODULE */
529