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/vmalloc.h>
19#include <linux/delay.h>
20#include <linux/interrupt.h>
21#include <linux/platform_device.h>
22
23#include <linux/fb.h>
24#include <linux/init.h>
25
26    /*
27     *  RAM we reserve for the frame buffer. This defines the maximum screen
28     *  size
29     *
30     *  The default can be overridden if the driver is compiled as a module
31     */
32
33#define VIDEOMEMSIZE	(1*1024*1024)	/* 1 MB */
34
35static void *videomemory;
36static u_long videomemorysize = VIDEOMEMSIZE;
37module_param(videomemorysize, ulong, 0);
38MODULE_PARM_DESC(videomemorysize, "RAM available to frame buffer (in bytes)");
39
40static char *mode_option = NULL;
41module_param(mode_option, charp, 0);
42MODULE_PARM_DESC(mode_option, "Preferred video mode (e.g. 640x480-8@60)");
43
44static const struct fb_videomode vfb_default = {
45	.xres =		640,
46	.yres =		480,
47	.pixclock =	20000,
48	.left_margin =	64,
49	.right_margin =	64,
50	.upper_margin =	32,
51	.lower_margin =	32,
52	.hsync_len =	64,
53	.vsync_len =	2,
54	.vmode =	FB_VMODE_NONINTERLACED,
55};
56
57static struct fb_fix_screeninfo vfb_fix = {
58	.id =		"Virtual FB",
59	.type =		FB_TYPE_PACKED_PIXELS,
60	.visual =	FB_VISUAL_PSEUDOCOLOR,
61	.xpanstep =	1,
62	.ypanstep =	1,
63	.ywrapstep =	1,
64	.accel =	FB_ACCEL_NONE,
65};
66
67static bool vfb_enable __initdata = 0;	/* disabled by default */
68module_param(vfb_enable, bool, 0);
69MODULE_PARM_DESC(vfb_enable, "Enable Virtual FB driver");
70
71static int vfb_check_var(struct fb_var_screeninfo *var,
72			 struct fb_info *info);
73static int vfb_set_par(struct fb_info *info);
74static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
75			 u_int transp, struct fb_info *info);
76static int vfb_pan_display(struct fb_var_screeninfo *var,
77			   struct fb_info *info);
78static int vfb_mmap(struct fb_info *info,
79		    struct vm_area_struct *vma);
80
81static const struct fb_ops vfb_ops = {
82	.fb_read        = fb_sys_read,
83	.fb_write       = fb_sys_write,
84	.fb_check_var	= vfb_check_var,
85	.fb_set_par	= vfb_set_par,
86	.fb_setcolreg	= vfb_setcolreg,
87	.fb_pan_display	= vfb_pan_display,
88	.fb_fillrect	= sys_fillrect,
89	.fb_copyarea	= sys_copyarea,
90	.fb_imageblit	= sys_imageblit,
91	.fb_mmap	= vfb_mmap,
92};
93
94    /*
95     *  Internal routines
96     */
97
98static u_long get_line_length(int xres_virtual, int bpp)
99{
100	u_long length;
101
102	length = xres_virtual * bpp;
103	length = (length + 31) & ~31;
104	length >>= 3;
105	return (length);
106}
107
108    /*
109     *  Setting the video mode has been split into two parts.
110     *  First part, xxxfb_check_var, must not write anything
111     *  to hardware, it should only verify and adjust var.
112     *  This means it doesn't alter par but it does use hardware
113     *  data from it to check this var.
114     */
115
116static int vfb_check_var(struct fb_var_screeninfo *var,
117			 struct fb_info *info)
118{
119	u_long line_length;
120
121	/*
122	 *  FB_VMODE_CONUPDATE and FB_VMODE_SMOOTH_XPAN are equal!
123	 *  as FB_VMODE_SMOOTH_XPAN is only used internally
124	 */
125
126	if (var->vmode & FB_VMODE_CONUPDATE) {
127		var->vmode |= FB_VMODE_YWRAP;
128		var->xoffset = info->var.xoffset;
129		var->yoffset = info->var.yoffset;
130	}
131
132	/*
133	 *  Some very basic checks
134	 */
135	if (!var->xres)
136		var->xres = 1;
137	if (!var->yres)
138		var->yres = 1;
139	if (var->xres > var->xres_virtual)
140		var->xres_virtual = var->xres;
141	if (var->yres > var->yres_virtual)
142		var->yres_virtual = var->yres;
143	if (var->bits_per_pixel <= 1)
144		var->bits_per_pixel = 1;
145	else if (var->bits_per_pixel <= 8)
146		var->bits_per_pixel = 8;
147	else if (var->bits_per_pixel <= 16)
148		var->bits_per_pixel = 16;
149	else if (var->bits_per_pixel <= 24)
150		var->bits_per_pixel = 24;
151	else if (var->bits_per_pixel <= 32)
152		var->bits_per_pixel = 32;
153	else
154		return -EINVAL;
155
156	if (var->xres_virtual < var->xoffset + var->xres)
157		var->xres_virtual = var->xoffset + var->xres;
158	if (var->yres_virtual < var->yoffset + var->yres)
159		var->yres_virtual = var->yoffset + var->yres;
160
161	/*
162	 *  Memory limit
163	 */
164	line_length =
165	    get_line_length(var->xres_virtual, var->bits_per_pixel);
166	if (line_length * var->yres_virtual > videomemorysize)
167		return -ENOMEM;
168
169	/*
170	 * Now that we checked it we alter var. The reason being is that the video
171	 * mode passed in might not work but slight changes to it might make it
172	 * work. This way we let the user know what is acceptable.
173	 */
174	switch (var->bits_per_pixel) {
175	case 1:
176	case 8:
177		var->red.offset = 0;
178		var->red.length = 8;
179		var->green.offset = 0;
180		var->green.length = 8;
181		var->blue.offset = 0;
182		var->blue.length = 8;
183		var->transp.offset = 0;
184		var->transp.length = 0;
185		break;
186	case 16:		/* RGBA 5551 */
187		if (var->transp.length) {
188			var->red.offset = 0;
189			var->red.length = 5;
190			var->green.offset = 5;
191			var->green.length = 5;
192			var->blue.offset = 10;
193			var->blue.length = 5;
194			var->transp.offset = 15;
195			var->transp.length = 1;
196		} else {	/* RGB 565 */
197			var->red.offset = 0;
198			var->red.length = 5;
199			var->green.offset = 5;
200			var->green.length = 6;
201			var->blue.offset = 11;
202			var->blue.length = 5;
203			var->transp.offset = 0;
204			var->transp.length = 0;
205		}
206		break;
207	case 24:		/* RGB 888 */
208		var->red.offset = 0;
209		var->red.length = 8;
210		var->green.offset = 8;
211		var->green.length = 8;
212		var->blue.offset = 16;
213		var->blue.length = 8;
214		var->transp.offset = 0;
215		var->transp.length = 0;
216		break;
217	case 32:		/* RGBA 8888 */
218		var->red.offset = 0;
219		var->red.length = 8;
220		var->green.offset = 8;
221		var->green.length = 8;
222		var->blue.offset = 16;
223		var->blue.length = 8;
224		var->transp.offset = 24;
225		var->transp.length = 8;
226		break;
227	}
228	var->red.msb_right = 0;
229	var->green.msb_right = 0;
230	var->blue.msb_right = 0;
231	var->transp.msb_right = 0;
232
233	return 0;
234}
235
236/* This routine actually sets the video mode. It's in here where we
237 * the hardware state info->par and fix which can be affected by the
238 * change in par. For this driver it doesn't do much.
239 */
240static int vfb_set_par(struct fb_info *info)
241{
242	switch (info->var.bits_per_pixel) {
243	case 1:
244		info->fix.visual = FB_VISUAL_MONO01;
245		break;
246	case 8:
247		info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
248		break;
249	case 16:
250	case 24:
251	case 32:
252		info->fix.visual = FB_VISUAL_TRUECOLOR;
253		break;
254	}
255
256	info->fix.line_length = get_line_length(info->var.xres_virtual,
257						info->var.bits_per_pixel);
258
259	return 0;
260}
261
262    /*
263     *  Set a single color register. The values supplied are already
264     *  rounded down to the hardware's capabilities (according to the
265     *  entries in the var structure). Return != 0 for invalid regno.
266     */
267
268static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
269			 u_int transp, struct fb_info *info)
270{
271	if (regno >= 256)	/* no. of hw registers */
272		return 1;
273	/*
274	 * Program hardware... do anything you want with transp
275	 */
276
277	/* grayscale works only partially under directcolor */
278	if (info->var.grayscale) {
279		/* grayscale = 0.30*R + 0.59*G + 0.11*B */
280		red = green = blue =
281		    (red * 77 + green * 151 + blue * 28) >> 8;
282	}
283
284	/* Directcolor:
285	 *   var->{color}.offset contains start of bitfield
286	 *   var->{color}.length contains length of bitfield
287	 *   {hardwarespecific} contains width of RAMDAC
288	 *   cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset)
289	 *   RAMDAC[X] is programmed to (red, green, blue)
290	 *
291	 * Pseudocolor:
292	 *    var->{color}.offset is 0 unless the palette index takes less than
293	 *                        bits_per_pixel bits and is stored in the upper
294	 *                        bits of the pixel value
295	 *    var->{color}.length is set so that 1 << length is the number of available
296	 *                        palette entries
297	 *    cmap is not used
298	 *    RAMDAC[X] is programmed to (red, green, blue)
299	 *
300	 * Truecolor:
301	 *    does not use DAC. Usually 3 are present.
302	 *    var->{color}.offset contains start of bitfield
303	 *    var->{color}.length contains length of bitfield
304	 *    cmap is programmed to (red << red.offset) | (green << green.offset) |
305	 *                      (blue << blue.offset) | (transp << transp.offset)
306	 *    RAMDAC does not exist
307	 */
308#define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
309	switch (info->fix.visual) {
310	case FB_VISUAL_TRUECOLOR:
311	case FB_VISUAL_PSEUDOCOLOR:
312		red = CNVT_TOHW(red, info->var.red.length);
313		green = CNVT_TOHW(green, info->var.green.length);
314		blue = CNVT_TOHW(blue, info->var.blue.length);
315		transp = CNVT_TOHW(transp, info->var.transp.length);
316		break;
317	case FB_VISUAL_DIRECTCOLOR:
318		red = CNVT_TOHW(red, 8);	/* expect 8 bit DAC */
319		green = CNVT_TOHW(green, 8);
320		blue = CNVT_TOHW(blue, 8);
321		/* hey, there is bug in transp handling... */
322		transp = CNVT_TOHW(transp, 8);
323		break;
324	}
325#undef CNVT_TOHW
326	/* Truecolor has hardware independent palette */
327	if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
328		u32 v;
329
330		if (regno >= 16)
331			return 1;
332
333		v = (red << info->var.red.offset) |
334		    (green << info->var.green.offset) |
335		    (blue << info->var.blue.offset) |
336		    (transp << info->var.transp.offset);
337		switch (info->var.bits_per_pixel) {
338		case 8:
339			break;
340		case 16:
341			((u32 *) (info->pseudo_palette))[regno] = v;
342			break;
343		case 24:
344		case 32:
345			((u32 *) (info->pseudo_palette))[regno] = v;
346			break;
347		}
348		return 0;
349	}
350	return 0;
351}
352
353    /*
354     *  Pan or Wrap the Display
355     *
356     *  This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag
357     */
358
359static int vfb_pan_display(struct fb_var_screeninfo *var,
360			   struct fb_info *info)
361{
362	if (var->vmode & FB_VMODE_YWRAP) {
363		if (var->yoffset >= info->var.yres_virtual ||
364		    var->xoffset)
365			return -EINVAL;
366	} else {
367		if (var->xoffset + info->var.xres > info->var.xres_virtual ||
368		    var->yoffset + info->var.yres > info->var.yres_virtual)
369			return -EINVAL;
370	}
371	info->var.xoffset = var->xoffset;
372	info->var.yoffset = var->yoffset;
373	if (var->vmode & FB_VMODE_YWRAP)
374		info->var.vmode |= FB_VMODE_YWRAP;
375	else
376		info->var.vmode &= ~FB_VMODE_YWRAP;
377	return 0;
378}
379
380    /*
381     *  Most drivers don't need their own mmap function
382     */
383
384static int vfb_mmap(struct fb_info *info,
385		    struct vm_area_struct *vma)
386{
387	return remap_vmalloc_range(vma, (void *)info->fix.smem_start, vma->vm_pgoff);
388}
389
390#ifndef MODULE
391/*
392 * The virtual framebuffer driver is only enabled if explicitly
393 * requested by passing 'video=vfb:' (or any actual options).
394 */
395static int __init vfb_setup(char *options)
396{
397	char *this_opt;
398
399	vfb_enable = 0;
400
401	if (!options)
402		return 1;
403
404	vfb_enable = 1;
405
406	if (!*options)
407		return 1;
408
409	while ((this_opt = strsep(&options, ",")) != NULL) {
410		if (!*this_opt)
411			continue;
412		/* Test disable for backwards compatibility */
413		if (!strcmp(this_opt, "disable"))
414			vfb_enable = 0;
415		else
416			mode_option = this_opt;
417	}
418	return 1;
419}
420#endif  /*  MODULE  */
421
422    /*
423     *  Initialisation
424     */
425
426static int vfb_probe(struct platform_device *dev)
427{
428	struct fb_info *info;
429	unsigned int size = PAGE_ALIGN(videomemorysize);
430	int retval = -ENOMEM;
431
432	/*
433	 * For real video cards we use ioremap.
434	 */
435	if (!(videomemory = vmalloc_32_user(size)))
436		return retval;
437
438	info = framebuffer_alloc(sizeof(u32) * 256, &dev->dev);
439	if (!info)
440		goto err;
441
442	info->screen_base = (char __iomem *)videomemory;
443	info->fbops = &vfb_ops;
444
445	if (!fb_find_mode(&info->var, info, mode_option,
446			  NULL, 0, &vfb_default, 8)){
447		fb_err(info, "Unable to find usable video mode.\n");
448		retval = -EINVAL;
449		goto err1;
450	}
451
452	vfb_fix.smem_start = (unsigned long) videomemory;
453	vfb_fix.smem_len = videomemorysize;
454	info->fix = vfb_fix;
455	info->pseudo_palette = info->par;
456	info->par = NULL;
457	info->flags = FBINFO_FLAG_DEFAULT;
458
459	retval = fb_alloc_cmap(&info->cmap, 256, 0);
460	if (retval < 0)
461		goto err1;
462
463	retval = register_framebuffer(info);
464	if (retval < 0)
465		goto err2;
466	platform_set_drvdata(dev, info);
467
468	vfb_set_par(info);
469
470	fb_info(info, "Virtual frame buffer device, using %ldK of video memory\n",
471		videomemorysize >> 10);
472	return 0;
473err2:
474	fb_dealloc_cmap(&info->cmap);
475err1:
476	framebuffer_release(info);
477err:
478	vfree(videomemory);
479	return retval;
480}
481
482static int vfb_remove(struct platform_device *dev)
483{
484	struct fb_info *info = platform_get_drvdata(dev);
485
486	if (info) {
487		unregister_framebuffer(info);
488		vfree(videomemory);
489		fb_dealloc_cmap(&info->cmap);
490		framebuffer_release(info);
491	}
492	return 0;
493}
494
495static struct platform_driver vfb_driver = {
496	.probe	= vfb_probe,
497	.remove = vfb_remove,
498	.driver = {
499		.name	= "vfb",
500	},
501};
502
503static struct platform_device *vfb_device;
504
505static int __init vfb_init(void)
506{
507	int ret = 0;
508
509#ifndef MODULE
510	char *option = NULL;
511
512	if (fb_get_options("vfb", &option))
513		return -ENODEV;
514	vfb_setup(option);
515#endif
516
517	if (!vfb_enable)
518		return -ENXIO;
519
520	ret = platform_driver_register(&vfb_driver);
521
522	if (!ret) {
523		vfb_device = platform_device_alloc("vfb", 0);
524
525		if (vfb_device)
526			ret = platform_device_add(vfb_device);
527		else
528			ret = -ENOMEM;
529
530		if (ret) {
531			platform_device_put(vfb_device);
532			platform_driver_unregister(&vfb_driver);
533		}
534	}
535
536	return ret;
537}
538
539module_init(vfb_init);
540
541#ifdef MODULE
542static void __exit vfb_exit(void)
543{
544	platform_device_unregister(vfb_device);
545	platform_driver_unregister(&vfb_driver);
546}
547
548module_exit(vfb_exit);
549
550MODULE_LICENSE("GPL");
551#endif				/* MODULE */
552