xref: /linux/drivers/video/fbdev/vfb.c (revision a13d7201d7deedcbb6ac6efa94a1a7d34d3d79ec) 
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 
35 static void *videomemory;
36 static u_long videomemorysize = VIDEOMEMSIZE;
37 module_param(videomemorysize, ulong, 0);
38 
39 /**********************************************************************
40  *
41  * Memory management
42  *
43  **********************************************************************/
44 static void *rvmalloc(unsigned long size)
45 {
46 	void *mem;
47 	unsigned long adr;
48 
49 	size = PAGE_ALIGN(size);
50 	mem = vmalloc_32(size);
51 	if (!mem)
52 		return NULL;
53 
54 	memset(mem, 0, size); /* Clear the ram out, no junk to the user */
55 	adr = (unsigned long) mem;
56 	while (size > 0) {
57 		SetPageReserved(vmalloc_to_page((void *)adr));
58 		adr += PAGE_SIZE;
59 		size -= PAGE_SIZE;
60 	}
61 
62 	return mem;
63 }
64 
65 static void rvfree(void *mem, unsigned long size)
66 {
67 	unsigned long adr;
68 
69 	if (!mem)
70 		return;
71 
72 	adr = (unsigned long) mem;
73 	while ((long) size > 0) {
74 		ClearPageReserved(vmalloc_to_page((void *)adr));
75 		adr += PAGE_SIZE;
76 		size -= PAGE_SIZE;
77 	}
78 	vfree(mem);
79 }
80 
81 static struct fb_var_screeninfo vfb_default = {
82 	.xres =		640,
83 	.yres =		480,
84 	.xres_virtual =	640,
85 	.yres_virtual =	480,
86 	.bits_per_pixel = 8,
87 	.red =		{ 0, 8, 0 },
88       	.green =	{ 0, 8, 0 },
89       	.blue =		{ 0, 8, 0 },
90       	.activate =	FB_ACTIVATE_TEST,
91       	.height =	-1,
92       	.width =	-1,
93       	.pixclock =	20000,
94       	.left_margin =	64,
95       	.right_margin =	64,
96       	.upper_margin =	32,
97       	.lower_margin =	32,
98       	.hsync_len =	64,
99       	.vsync_len =	2,
100       	.vmode =	FB_VMODE_NONINTERLACED,
101 };
102 
103 static struct fb_fix_screeninfo vfb_fix = {
104 	.id =		"Virtual FB",
105 	.type =		FB_TYPE_PACKED_PIXELS,
106 	.visual =	FB_VISUAL_PSEUDOCOLOR,
107 	.xpanstep =	1,
108 	.ypanstep =	1,
109 	.ywrapstep =	1,
110 	.accel =	FB_ACCEL_NONE,
111 };
112 
113 static bool vfb_enable __initdata = 0;	/* disabled by default */
114 module_param(vfb_enable, bool, 0);
115 
116 static int vfb_check_var(struct fb_var_screeninfo *var,
117 			 struct fb_info *info);
118 static int vfb_set_par(struct fb_info *info);
119 static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
120 			 u_int transp, struct fb_info *info);
121 static int vfb_pan_display(struct fb_var_screeninfo *var,
122 			   struct fb_info *info);
123 static int vfb_mmap(struct fb_info *info,
124 		    struct vm_area_struct *vma);
125 
126 static struct fb_ops vfb_ops = {
127 	.fb_read        = fb_sys_read,
128 	.fb_write       = fb_sys_write,
129 	.fb_check_var	= vfb_check_var,
130 	.fb_set_par	= vfb_set_par,
131 	.fb_setcolreg	= vfb_setcolreg,
132 	.fb_pan_display	= vfb_pan_display,
133 	.fb_fillrect	= sys_fillrect,
134 	.fb_copyarea	= sys_copyarea,
135 	.fb_imageblit	= sys_imageblit,
136 	.fb_mmap	= vfb_mmap,
137 };
138 
139     /*
140      *  Internal routines
141      */
142 
143 static u_long get_line_length(int xres_virtual, int bpp)
144 {
145 	u_long length;
146 
147 	length = xres_virtual * bpp;
148 	length = (length + 31) & ~31;
149 	length >>= 3;
150 	return (length);
151 }
152 
153     /*
154      *  Setting the video mode has been split into two parts.
155      *  First part, xxxfb_check_var, must not write anything
156      *  to hardware, it should only verify and adjust var.
157      *  This means it doesn't alter par but it does use hardware
158      *  data from it to check this var.
159      */
160 
161 static int vfb_check_var(struct fb_var_screeninfo *var,
162 			 struct fb_info *info)
163 {
164 	u_long line_length;
165 
166 	/*
167 	 *  FB_VMODE_CONUPDATE and FB_VMODE_SMOOTH_XPAN are equal!
168 	 *  as FB_VMODE_SMOOTH_XPAN is only used internally
169 	 */
170 
171 	if (var->vmode & FB_VMODE_CONUPDATE) {
172 		var->vmode |= FB_VMODE_YWRAP;
173 		var->xoffset = info->var.xoffset;
174 		var->yoffset = info->var.yoffset;
175 	}
176 
177 	/*
178 	 *  Some very basic checks
179 	 */
180 	if (!var->xres)
181 		var->xres = 1;
182 	if (!var->yres)
183 		var->yres = 1;
184 	if (var->xres > var->xres_virtual)
185 		var->xres_virtual = var->xres;
186 	if (var->yres > var->yres_virtual)
187 		var->yres_virtual = var->yres;
188 	if (var->bits_per_pixel <= 1)
189 		var->bits_per_pixel = 1;
190 	else if (var->bits_per_pixel <= 8)
191 		var->bits_per_pixel = 8;
192 	else if (var->bits_per_pixel <= 16)
193 		var->bits_per_pixel = 16;
194 	else if (var->bits_per_pixel <= 24)
195 		var->bits_per_pixel = 24;
196 	else if (var->bits_per_pixel <= 32)
197 		var->bits_per_pixel = 32;
198 	else
199 		return -EINVAL;
200 
201 	if (var->xres_virtual < var->xoffset + var->xres)
202 		var->xres_virtual = var->xoffset + var->xres;
203 	if (var->yres_virtual < var->yoffset + var->yres)
204 		var->yres_virtual = var->yoffset + var->yres;
205 
206 	/*
207 	 *  Memory limit
208 	 */
209 	line_length =
210 	    get_line_length(var->xres_virtual, var->bits_per_pixel);
211 	if (line_length * var->yres_virtual > videomemorysize)
212 		return -ENOMEM;
213 
214 	/*
215 	 * Now that we checked it we alter var. The reason being is that the video
216 	 * mode passed in might not work but slight changes to it might make it
217 	 * work. This way we let the user know what is acceptable.
218 	 */
219 	switch (var->bits_per_pixel) {
220 	case 1:
221 	case 8:
222 		var->red.offset = 0;
223 		var->red.length = 8;
224 		var->green.offset = 0;
225 		var->green.length = 8;
226 		var->blue.offset = 0;
227 		var->blue.length = 8;
228 		var->transp.offset = 0;
229 		var->transp.length = 0;
230 		break;
231 	case 16:		/* RGBA 5551 */
232 		if (var->transp.length) {
233 			var->red.offset = 0;
234 			var->red.length = 5;
235 			var->green.offset = 5;
236 			var->green.length = 5;
237 			var->blue.offset = 10;
238 			var->blue.length = 5;
239 			var->transp.offset = 15;
240 			var->transp.length = 1;
241 		} else {	/* RGB 565 */
242 			var->red.offset = 0;
243 			var->red.length = 5;
244 			var->green.offset = 5;
245 			var->green.length = 6;
246 			var->blue.offset = 11;
247 			var->blue.length = 5;
248 			var->transp.offset = 0;
249 			var->transp.length = 0;
250 		}
251 		break;
252 	case 24:		/* RGB 888 */
253 		var->red.offset = 0;
254 		var->red.length = 8;
255 		var->green.offset = 8;
256 		var->green.length = 8;
257 		var->blue.offset = 16;
258 		var->blue.length = 8;
259 		var->transp.offset = 0;
260 		var->transp.length = 0;
261 		break;
262 	case 32:		/* RGBA 8888 */
263 		var->red.offset = 0;
264 		var->red.length = 8;
265 		var->green.offset = 8;
266 		var->green.length = 8;
267 		var->blue.offset = 16;
268 		var->blue.length = 8;
269 		var->transp.offset = 24;
270 		var->transp.length = 8;
271 		break;
272 	}
273 	var->red.msb_right = 0;
274 	var->green.msb_right = 0;
275 	var->blue.msb_right = 0;
276 	var->transp.msb_right = 0;
277 
278 	return 0;
279 }
280 
281 /* This routine actually sets the video mode. It's in here where we
282  * the hardware state info->par and fix which can be affected by the
283  * change in par. For this driver it doesn't do much.
284  */
285 static int vfb_set_par(struct fb_info *info)
286 {
287 	info->fix.line_length = get_line_length(info->var.xres_virtual,
288 						info->var.bits_per_pixel);
289 	return 0;
290 }
291 
292     /*
293      *  Set a single color register. The values supplied are already
294      *  rounded down to the hardware's capabilities (according to the
295      *  entries in the var structure). Return != 0 for invalid regno.
296      */
297 
298 static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
299 			 u_int transp, struct fb_info *info)
300 {
301 	if (regno >= 256)	/* no. of hw registers */
302 		return 1;
303 	/*
304 	 * Program hardware... do anything you want with transp
305 	 */
306 
307 	/* grayscale works only partially under directcolor */
308 	if (info->var.grayscale) {
309 		/* grayscale = 0.30*R + 0.59*G + 0.11*B */
310 		red = green = blue =
311 		    (red * 77 + green * 151 + blue * 28) >> 8;
312 	}
313 
314 	/* Directcolor:
315 	 *   var->{color}.offset contains start of bitfield
316 	 *   var->{color}.length contains length of bitfield
317 	 *   {hardwarespecific} contains width of RAMDAC
318 	 *   cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset)
319 	 *   RAMDAC[X] is programmed to (red, green, blue)
320 	 *
321 	 * Pseudocolor:
322 	 *    var->{color}.offset is 0 unless the palette index takes less than
323 	 *                        bits_per_pixel bits and is stored in the upper
324 	 *                        bits of the pixel value
325 	 *    var->{color}.length is set so that 1 << length is the number of available
326 	 *                        palette entries
327 	 *    cmap is not used
328 	 *    RAMDAC[X] is programmed to (red, green, blue)
329 	 *
330 	 * Truecolor:
331 	 *    does not use DAC. Usually 3 are present.
332 	 *    var->{color}.offset contains start of bitfield
333 	 *    var->{color}.length contains length of bitfield
334 	 *    cmap is programmed to (red << red.offset) | (green << green.offset) |
335 	 *                      (blue << blue.offset) | (transp << transp.offset)
336 	 *    RAMDAC does not exist
337 	 */
338 #define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
339 	switch (info->fix.visual) {
340 	case FB_VISUAL_TRUECOLOR:
341 	case FB_VISUAL_PSEUDOCOLOR:
342 		red = CNVT_TOHW(red, info->var.red.length);
343 		green = CNVT_TOHW(green, info->var.green.length);
344 		blue = CNVT_TOHW(blue, info->var.blue.length);
345 		transp = CNVT_TOHW(transp, info->var.transp.length);
346 		break;
347 	case FB_VISUAL_DIRECTCOLOR:
348 		red = CNVT_TOHW(red, 8);	/* expect 8 bit DAC */
349 		green = CNVT_TOHW(green, 8);
350 		blue = CNVT_TOHW(blue, 8);
351 		/* hey, there is bug in transp handling... */
352 		transp = CNVT_TOHW(transp, 8);
353 		break;
354 	}
355 #undef CNVT_TOHW
356 	/* Truecolor has hardware independent palette */
357 	if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
358 		u32 v;
359 
360 		if (regno >= 16)
361 			return 1;
362 
363 		v = (red << info->var.red.offset) |
364 		    (green << info->var.green.offset) |
365 		    (blue << info->var.blue.offset) |
366 		    (transp << info->var.transp.offset);
367 		switch (info->var.bits_per_pixel) {
368 		case 8:
369 			break;
370 		case 16:
371 			((u32 *) (info->pseudo_palette))[regno] = v;
372 			break;
373 		case 24:
374 		case 32:
375 			((u32 *) (info->pseudo_palette))[regno] = v;
376 			break;
377 		}
378 		return 0;
379 	}
380 	return 0;
381 }
382 
383     /*
384      *  Pan or Wrap the Display
385      *
386      *  This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag
387      */
388 
389 static int vfb_pan_display(struct fb_var_screeninfo *var,
390 			   struct fb_info *info)
391 {
392 	if (var->vmode & FB_VMODE_YWRAP) {
393 		if (var->yoffset >= info->var.yres_virtual ||
394 		    var->xoffset)
395 			return -EINVAL;
396 	} else {
397 		if (var->xoffset + info->var.xres > info->var.xres_virtual ||
398 		    var->yoffset + info->var.yres > info->var.yres_virtual)
399 			return -EINVAL;
400 	}
401 	info->var.xoffset = var->xoffset;
402 	info->var.yoffset = var->yoffset;
403 	if (var->vmode & FB_VMODE_YWRAP)
404 		info->var.vmode |= FB_VMODE_YWRAP;
405 	else
406 		info->var.vmode &= ~FB_VMODE_YWRAP;
407 	return 0;
408 }
409 
410     /*
411      *  Most drivers don't need their own mmap function
412      */
413 
414 static int vfb_mmap(struct fb_info *info,
415 		    struct vm_area_struct *vma)
416 {
417 	unsigned long start = vma->vm_start;
418 	unsigned long size = vma->vm_end - vma->vm_start;
419 	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
420 	unsigned long page, pos;
421 
422 	if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
423 		return -EINVAL;
424 	if (size > info->fix.smem_len)
425 		return -EINVAL;
426 	if (offset > info->fix.smem_len - size)
427 		return -EINVAL;
428 
429 	pos = (unsigned long)info->fix.smem_start + offset;
430 
431 	while (size > 0) {
432 		page = vmalloc_to_pfn((void *)pos);
433 		if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED)) {
434 			return -EAGAIN;
435 		}
436 		start += PAGE_SIZE;
437 		pos += PAGE_SIZE;
438 		if (size > PAGE_SIZE)
439 			size -= PAGE_SIZE;
440 		else
441 			size = 0;
442 	}
443 
444 	return 0;
445 
446 }
447 
448 #ifndef MODULE
449 /*
450  * The virtual framebuffer driver is only enabled if explicitly
451  * requested by passing 'video=vfb:' (or any actual options).
452  */
453 static int __init vfb_setup(char *options)
454 {
455 	char *this_opt;
456 
457 	vfb_enable = 0;
458 
459 	if (!options)
460 		return 1;
461 
462 	vfb_enable = 1;
463 
464 	if (!*options)
465 		return 1;
466 
467 	while ((this_opt = strsep(&options, ",")) != NULL) {
468 		if (!*this_opt)
469 			continue;
470 		/* Test disable for backwards compatibility */
471 		if (!strcmp(this_opt, "disable"))
472 			vfb_enable = 0;
473 	}
474 	return 1;
475 }
476 #endif  /*  MODULE  */
477 
478     /*
479      *  Initialisation
480      */
481 
482 static int vfb_probe(struct platform_device *dev)
483 {
484 	struct fb_info *info;
485 	int retval = -ENOMEM;
486 
487 	/*
488 	 * For real video cards we use ioremap.
489 	 */
490 	if (!(videomemory = rvmalloc(videomemorysize)))
491 		return retval;
492 
493 	/*
494 	 * VFB must clear memory to prevent kernel info
495 	 * leakage into userspace
496 	 * VGA-based drivers MUST NOT clear memory if
497 	 * they want to be able to take over vgacon
498 	 */
499 	memset(videomemory, 0, videomemorysize);
500 
501 	info = framebuffer_alloc(sizeof(u32) * 256, &dev->dev);
502 	if (!info)
503 		goto err;
504 
505 	info->screen_base = (char __iomem *)videomemory;
506 	info->fbops = &vfb_ops;
507 
508 	retval = fb_find_mode(&info->var, info, NULL,
509 			      NULL, 0, NULL, 8);
510 
511 	if (!retval || (retval == 4))
512 		info->var = vfb_default;
513 	vfb_fix.smem_start = (unsigned long) videomemory;
514 	vfb_fix.smem_len = videomemorysize;
515 	info->fix = vfb_fix;
516 	info->pseudo_palette = info->par;
517 	info->par = NULL;
518 	info->flags = FBINFO_FLAG_DEFAULT;
519 
520 	retval = fb_alloc_cmap(&info->cmap, 256, 0);
521 	if (retval < 0)
522 		goto err1;
523 
524 	retval = register_framebuffer(info);
525 	if (retval < 0)
526 		goto err2;
527 	platform_set_drvdata(dev, info);
528 
529 	fb_info(info, "Virtual frame buffer device, using %ldK of video memory\n",
530 		videomemorysize >> 10);
531 	return 0;
532 err2:
533 	fb_dealloc_cmap(&info->cmap);
534 err1:
535 	framebuffer_release(info);
536 err:
537 	rvfree(videomemory, videomemorysize);
538 	return retval;
539 }
540 
541 static int vfb_remove(struct platform_device *dev)
542 {
543 	struct fb_info *info = platform_get_drvdata(dev);
544 
545 	if (info) {
546 		unregister_framebuffer(info);
547 		rvfree(videomemory, videomemorysize);
548 		fb_dealloc_cmap(&info->cmap);
549 		framebuffer_release(info);
550 	}
551 	return 0;
552 }
553 
554 static struct platform_driver vfb_driver = {
555 	.probe	= vfb_probe,
556 	.remove = vfb_remove,
557 	.driver = {
558 		.name	= "vfb",
559 	},
560 };
561 
562 static struct platform_device *vfb_device;
563 
564 static int __init vfb_init(void)
565 {
566 	int ret = 0;
567 
568 #ifndef MODULE
569 	char *option = NULL;
570 
571 	if (fb_get_options("vfb", &option))
572 		return -ENODEV;
573 	vfb_setup(option);
574 #endif
575 
576 	if (!vfb_enable)
577 		return -ENXIO;
578 
579 	ret = platform_driver_register(&vfb_driver);
580 
581 	if (!ret) {
582 		vfb_device = platform_device_alloc("vfb", 0);
583 
584 		if (vfb_device)
585 			ret = platform_device_add(vfb_device);
586 		else
587 			ret = -ENOMEM;
588 
589 		if (ret) {
590 			platform_device_put(vfb_device);
591 			platform_driver_unregister(&vfb_driver);
592 		}
593 	}
594 
595 	return ret;
596 }
597 
598 module_init(vfb_init);
599 
600 #ifdef MODULE
601 static void __exit vfb_exit(void)
602 {
603 	platform_device_unregister(vfb_device);
604 	platform_driver_unregister(&vfb_driver);
605 }
606 
607 module_exit(vfb_exit);
608 
609 MODULE_LICENSE("GPL");
610 #endif				/* MODULE */
611