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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 void vfb_destroy(struct fb_info *info)
82{
83 vfree(info->screen_buffer);
84 fb_dealloc_cmap(&info->cmap);
85 framebuffer_release(info);
86}
87
88static const struct fb_ops vfb_ops = {
89 .owner = THIS_MODULE,
90 __FB_DEFAULT_SYSMEM_OPS_RDWR,
91 .fb_check_var = vfb_check_var,
92 .fb_set_par = vfb_set_par,
93 .fb_setcolreg = vfb_setcolreg,
94 .fb_pan_display = vfb_pan_display,
95 __FB_DEFAULT_SYSMEM_OPS_DRAW,
96 .fb_mmap = vfb_mmap,
97 .fb_destroy = vfb_destroy,
98};
99
100 /*
101 * Internal routines
102 */
103
104static u_long get_line_length(int xres_virtual, int bpp)
105{
106 u_long length;
107
108 length = xres_virtual * bpp;
109 length = (length + 31) & ~31;
110 length >>= 3;
111 return (length);
112}
113
114 /*
115 * Setting the video mode has been split into two parts.
116 * First part, xxxfb_check_var, must not write anything
117 * to hardware, it should only verify and adjust var.
118 * This means it doesn't alter par but it does use hardware
119 * data from it to check this var.
120 */
121
122static int vfb_check_var(struct fb_var_screeninfo *var,
123 struct fb_info *info)
124{
125 u_long line_length;
126
127 /*
128 * FB_VMODE_CONUPDATE and FB_VMODE_SMOOTH_XPAN are equal!
129 * as FB_VMODE_SMOOTH_XPAN is only used internally
130 */
131
132 if (var->vmode & FB_VMODE_CONUPDATE) {
133 var->vmode |= FB_VMODE_YWRAP;
134 var->xoffset = info->var.xoffset;
135 var->yoffset = info->var.yoffset;
136 }
137
138 /*
139 * Some very basic checks
140 */
141 if (!var->xres)
142 var->xres = 1;
143 if (!var->yres)
144 var->yres = 1;
145 if (var->xres > var->xres_virtual)
146 var->xres_virtual = var->xres;
147 if (var->yres > var->yres_virtual)
148 var->yres_virtual = var->yres;
149 if (var->bits_per_pixel <= 1)
150 var->bits_per_pixel = 1;
151 else if (var->bits_per_pixel <= 8)
152 var->bits_per_pixel = 8;
153 else if (var->bits_per_pixel <= 16)
154 var->bits_per_pixel = 16;
155 else if (var->bits_per_pixel <= 24)
156 var->bits_per_pixel = 24;
157 else if (var->bits_per_pixel <= 32)
158 var->bits_per_pixel = 32;
159 else
160 return -EINVAL;
161
162 if (var->xres_virtual < var->xoffset + var->xres)
163 var->xres_virtual = var->xoffset + var->xres;
164 if (var->yres_virtual < var->yoffset + var->yres)
165 var->yres_virtual = var->yoffset + var->yres;
166
167 /*
168 * Memory limit
169 */
170 line_length =
171 get_line_length(var->xres_virtual, var->bits_per_pixel);
172 if (line_length * var->yres_virtual > videomemorysize)
173 return -ENOMEM;
174
175 /*
176 * Now that we checked it we alter var. The reason being is that the video
177 * mode passed in might not work but slight changes to it might make it
178 * work. This way we let the user know what is acceptable.
179 */
180 switch (var->bits_per_pixel) {
181 case 1:
182 case 8:
183 var->red.offset = 0;
184 var->red.length = 8;
185 var->green.offset = 0;
186 var->green.length = 8;
187 var->blue.offset = 0;
188 var->blue.length = 8;
189 var->transp.offset = 0;
190 var->transp.length = 0;
191 break;
192 case 16: /* RGBA 5551 */
193 if (var->transp.length) {
194 var->red.offset = 0;
195 var->red.length = 5;
196 var->green.offset = 5;
197 var->green.length = 5;
198 var->blue.offset = 10;
199 var->blue.length = 5;
200 var->transp.offset = 15;
201 var->transp.length = 1;
202 } else { /* RGB 565 */
203 var->red.offset = 0;
204 var->red.length = 5;
205 var->green.offset = 5;
206 var->green.length = 6;
207 var->blue.offset = 11;
208 var->blue.length = 5;
209 var->transp.offset = 0;
210 var->transp.length = 0;
211 }
212 break;
213 case 24: /* RGB 888 */
214 var->red.offset = 0;
215 var->red.length = 8;
216 var->green.offset = 8;
217 var->green.length = 8;
218 var->blue.offset = 16;
219 var->blue.length = 8;
220 var->transp.offset = 0;
221 var->transp.length = 0;
222 break;
223 case 32: /* RGBA 8888 */
224 var->red.offset = 0;
225 var->red.length = 8;
226 var->green.offset = 8;
227 var->green.length = 8;
228 var->blue.offset = 16;
229 var->blue.length = 8;
230 var->transp.offset = 24;
231 var->transp.length = 8;
232 break;
233 }
234 var->red.msb_right = 0;
235 var->green.msb_right = 0;
236 var->blue.msb_right = 0;
237 var->transp.msb_right = 0;
238
239 return 0;
240}
241
242/* This routine actually sets the video mode. It's in here where we
243 * the hardware state info->par and fix which can be affected by the
244 * change in par. For this driver it doesn't do much.
245 */
246static int vfb_set_par(struct fb_info *info)
247{
248 switch (info->var.bits_per_pixel) {
249 case 1:
250 info->fix.visual = FB_VISUAL_MONO01;
251 break;
252 case 8:
253 info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
254 break;
255 case 16:
256 case 24:
257 case 32:
258 info->fix.visual = FB_VISUAL_TRUECOLOR;
259 break;
260 }
261
262 info->fix.line_length = get_line_length(info->var.xres_virtual,
263 info->var.bits_per_pixel);
264
265 return 0;
266}
267
268 /*
269 * Set a single color register. The values supplied are already
270 * rounded down to the hardware's capabilities (according to the
271 * entries in the var structure). Return != 0 for invalid regno.
272 */
273
274static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
275 u_int transp, struct fb_info *info)
276{
277 if (regno >= 256) /* no. of hw registers */
278 return 1;
279 /*
280 * Program hardware... do anything you want with transp
281 */
282
283 /* grayscale works only partially under directcolor */
284 if (info->var.grayscale) {
285 /* grayscale = 0.30*R + 0.59*G + 0.11*B */
286 red = green = blue =
287 (red * 77 + green * 151 + blue * 28) >> 8;
288 }
289
290 /* Directcolor:
291 * var->{color}.offset contains start of bitfield
292 * var->{color}.length contains length of bitfield
293 * {hardwarespecific} contains width of RAMDAC
294 * cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset)
295 * RAMDAC[X] is programmed to (red, green, blue)
296 *
297 * Pseudocolor:
298 * var->{color}.offset is 0 unless the palette index takes less than
299 * bits_per_pixel bits and is stored in the upper
300 * bits of the pixel value
301 * var->{color}.length is set so that 1 << length is the number of available
302 * palette entries
303 * cmap is not used
304 * RAMDAC[X] is programmed to (red, green, blue)
305 *
306 * Truecolor:
307 * does not use DAC. Usually 3 are present.
308 * var->{color}.offset contains start of bitfield
309 * var->{color}.length contains length of bitfield
310 * cmap is programmed to (red << red.offset) | (green << green.offset) |
311 * (blue << blue.offset) | (transp << transp.offset)
312 * RAMDAC does not exist
313 */
314#define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
315 switch (info->fix.visual) {
316 case FB_VISUAL_TRUECOLOR:
317 case FB_VISUAL_PSEUDOCOLOR:
318 red = CNVT_TOHW(red, info->var.red.length);
319 green = CNVT_TOHW(green, info->var.green.length);
320 blue = CNVT_TOHW(blue, info->var.blue.length);
321 transp = CNVT_TOHW(transp, info->var.transp.length);
322 break;
323 case FB_VISUAL_DIRECTCOLOR:
324 red = CNVT_TOHW(red, 8); /* expect 8 bit DAC */
325 green = CNVT_TOHW(green, 8);
326 blue = CNVT_TOHW(blue, 8);
327 /* hey, there is bug in transp handling... */
328 transp = CNVT_TOHW(transp, 8);
329 break;
330 }
331#undef CNVT_TOHW
332 /* Truecolor has hardware independent palette */
333 if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
334 u32 v;
335
336 if (regno >= 16)
337 return 1;
338
339 v = (red << info->var.red.offset) |
340 (green << info->var.green.offset) |
341 (blue << info->var.blue.offset) |
342 (transp << info->var.transp.offset);
343 switch (info->var.bits_per_pixel) {
344 case 8:
345 break;
346 case 16:
347 ((u32 *) (info->pseudo_palette))[regno] = v;
348 break;
349 case 24:
350 case 32:
351 ((u32 *) (info->pseudo_palette))[regno] = v;
352 break;
353 }
354 return 0;
355 }
356 return 0;
357}
358
359 /*
360 * Pan or Wrap the Display
361 *
362 * This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag
363 */
364
365static int vfb_pan_display(struct fb_var_screeninfo *var,
366 struct fb_info *info)
367{
368 if (var->vmode & FB_VMODE_YWRAP) {
369 if (var->yoffset >= info->var.yres_virtual ||
370 var->xoffset)
371 return -EINVAL;
372 } else {
373 if (var->xoffset + info->var.xres > info->var.xres_virtual ||
374 var->yoffset + info->var.yres > info->var.yres_virtual)
375 return -EINVAL;
376 }
377 info->var.xoffset = var->xoffset;
378 info->var.yoffset = var->yoffset;
379 if (var->vmode & FB_VMODE_YWRAP)
380 info->var.vmode |= FB_VMODE_YWRAP;
381 else
382 info->var.vmode &= ~FB_VMODE_YWRAP;
383 return 0;
384}
385
386 /*
387 * Most drivers don't need their own mmap function
388 */
389
390static int vfb_mmap(struct fb_info *info,
391 struct vm_area_struct *vma)
392{
393 vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
394
395 return remap_vmalloc_range(vma, (void *)info->fix.smem_start, vma->vm_pgoff);
396}
397
398#ifndef MODULE
399/*
400 * The virtual framebuffer driver is only enabled if explicitly
401 * requested by passing 'video=vfb:' (or any actual options).
402 */
403static int __init vfb_setup(char *options)
404{
405 char *this_opt;
406
407 vfb_enable = 0;
408
409 if (!options)
410 return 1;
411
412 vfb_enable = 1;
413
414 if (!*options)
415 return 1;
416
417 while ((this_opt = strsep(&options, ",")) != NULL) {
418 if (!*this_opt)
419 continue;
420 /* Test disable for backwards compatibility */
421 if (!strcmp(this_opt, "disable"))
422 vfb_enable = 0;
423 else
424 mode_option = this_opt;
425 }
426 return 1;
427}
428#endif /* MODULE */
429
430 /*
431 * Initialisation
432 */
433
434static int vfb_probe(struct platform_device *dev)
435{
436 struct fb_info *info;
437 unsigned int size = PAGE_ALIGN(videomemorysize);
438 int retval = -ENOMEM;
439
440 /*
441 * For real video cards we use ioremap.
442 */
443 if (!(videomemory = vmalloc_32_user(size)))
444 return retval;
445
446 info = framebuffer_alloc(sizeof(u32) * 256, &dev->dev);
447 if (!info)
448 goto err;
449
450 info->flags |= FBINFO_VIRTFB;
451 info->screen_buffer = videomemory;
452 info->fbops = &vfb_ops;
453
454 if (!fb_find_mode(&info->var, info, mode_option,
455 NULL, 0, &vfb_default, 8)){
456 fb_err(info, "Unable to find usable video mode.\n");
457 retval = -EINVAL;
458 goto err1;
459 }
460
461 vfb_fix.smem_start = (unsigned long) videomemory;
462 vfb_fix.smem_len = videomemorysize;
463 info->fix = vfb_fix;
464 info->pseudo_palette = info->par;
465 info->par = NULL;
466
467 retval = fb_alloc_cmap(&info->cmap, 256, 0);
468 if (retval < 0)
469 goto err1;
470
471 retval = register_framebuffer(info);
472 if (retval < 0)
473 goto err2;
474 platform_set_drvdata(dev, info);
475
476 vfb_set_par(info);
477
478 fb_info(info, "Virtual frame buffer device, using %ldK of video memory\n",
479 videomemorysize >> 10);
480 return 0;
481err2:
482 fb_dealloc_cmap(&info->cmap);
483err1:
484 framebuffer_release(info);
485err:
486 vfree(videomemory);
487 return retval;
488}
489
490static void vfb_remove(struct platform_device *dev)
491{
492 struct fb_info *info = platform_get_drvdata(dev);
493
494 if (info) {
495 unregister_framebuffer(info);
496 }
497}
498
499static struct platform_driver vfb_driver = {
500 .probe = vfb_probe,
501 .remove = vfb_remove,
502 .driver = {
503 .name = "vfb",
504 },
505};
506
507static struct platform_device *vfb_device;
508
509static int __init vfb_init(void)
510{
511 int ret = 0;
512
513#ifndef MODULE
514 char *option = NULL;
515
516 if (fb_get_options("vfb", &option))
517 return -ENODEV;
518 vfb_setup(option);
519#endif
520
521 if (!vfb_enable)
522 return -ENXIO;
523
524 ret = platform_driver_register(&vfb_driver);
525
526 if (!ret) {
527 vfb_device = platform_device_alloc("vfb", 0);
528
529 if (vfb_device)
530 ret = platform_device_add(vfb_device);
531 else
532 ret = -ENOMEM;
533
534 if (ret) {
535 platform_device_put(vfb_device);
536 platform_driver_unregister(&vfb_driver);
537 }
538 }
539
540 return ret;
541}
542
543module_init(vfb_init);
544
545#ifdef MODULE
546static void __exit vfb_exit(void)
547{
548 platform_device_unregister(vfb_device);
549 platform_driver_unregister(&vfb_driver);
550}
551
552module_exit(vfb_exit);
553
554MODULE_DESCRIPTION("Virtual Frame Buffer driver");
555MODULE_LICENSE("GPL");
556#endif /* MODULE */