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 MODULE_PARM_DESC(videomemorysize, "RAM available to frame buffer (in bytes)");
39
40 static char *mode_option = NULL;
41 module_param(mode_option, charp, 0);
42 MODULE_PARM_DESC(mode_option, "Preferred video mode (e.g. 640x480-8@60)");
43
44 static 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
57 static 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
67 static bool vfb_enable __initdata = 0; /* disabled by default */
68 module_param(vfb_enable, bool, 0);
69 MODULE_PARM_DESC(vfb_enable, "Enable Virtual FB driver");
70
71 static int vfb_check_var(struct fb_var_screeninfo *var,
72 struct fb_info *info);
73 static int vfb_set_par(struct fb_info *info);
74 static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
75 u_int transp, struct fb_info *info);
76 static int vfb_pan_display(struct fb_var_screeninfo *var,
77 struct fb_info *info);
78 static int vfb_mmap(struct fb_info *info,
79 struct vm_area_struct *vma);
80
81 static const struct fb_ops vfb_ops = {
82 .owner = THIS_MODULE,
83 __FB_DEFAULT_SYSMEM_OPS_RDWR,
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_DEFAULT_SYSMEM_OPS_DRAW,
89 .fb_mmap = vfb_mmap,
90 };
91
92 /*
93 * Internal routines
94 */
95
get_line_length(int xres_virtual,int bpp)96 static u_long get_line_length(int xres_virtual, int bpp)
97 {
98 u_long length;
99
100 length = xres_virtual * bpp;
101 length = (length + 31) & ~31;
102 length >>= 3;
103 return (length);
104 }
105
106 /*
107 * Setting the video mode has been split into two parts.
108 * First part, xxxfb_check_var, must not write anything
109 * to hardware, it should only verify and adjust var.
110 * This means it doesn't alter par but it does use hardware
111 * data from it to check this var.
112 */
113
vfb_check_var(struct fb_var_screeninfo * var,struct fb_info * info)114 static int vfb_check_var(struct fb_var_screeninfo *var,
115 struct fb_info *info)
116 {
117 u_long line_length;
118
119 /*
120 * FB_VMODE_CONUPDATE and FB_VMODE_SMOOTH_XPAN are equal!
121 * as FB_VMODE_SMOOTH_XPAN is only used internally
122 */
123
124 if (var->vmode & FB_VMODE_CONUPDATE) {
125 var->vmode |= FB_VMODE_YWRAP;
126 var->xoffset = info->var.xoffset;
127 var->yoffset = info->var.yoffset;
128 }
129
130 /*
131 * Some very basic checks
132 */
133 if (!var->xres)
134 var->xres = 1;
135 if (!var->yres)
136 var->yres = 1;
137 if (var->xres > var->xres_virtual)
138 var->xres_virtual = var->xres;
139 if (var->yres > var->yres_virtual)
140 var->yres_virtual = var->yres;
141 if (var->bits_per_pixel <= 1)
142 var->bits_per_pixel = 1;
143 else if (var->bits_per_pixel <= 8)
144 var->bits_per_pixel = 8;
145 else if (var->bits_per_pixel <= 16)
146 var->bits_per_pixel = 16;
147 else if (var->bits_per_pixel <= 24)
148 var->bits_per_pixel = 24;
149 else if (var->bits_per_pixel <= 32)
150 var->bits_per_pixel = 32;
151 else
152 return -EINVAL;
153
154 if (var->xres_virtual < var->xoffset + var->xres)
155 var->xres_virtual = var->xoffset + var->xres;
156 if (var->yres_virtual < var->yoffset + var->yres)
157 var->yres_virtual = var->yoffset + var->yres;
158
159 /*
160 * Memory limit
161 */
162 line_length =
163 get_line_length(var->xres_virtual, var->bits_per_pixel);
164 if (line_length * var->yres_virtual > videomemorysize)
165 return -ENOMEM;
166
167 /*
168 * Now that we checked it we alter var. The reason being is that the video
169 * mode passed in might not work but slight changes to it might make it
170 * work. This way we let the user know what is acceptable.
171 */
172 switch (var->bits_per_pixel) {
173 case 1:
174 case 8:
175 var->red.offset = 0;
176 var->red.length = 8;
177 var->green.offset = 0;
178 var->green.length = 8;
179 var->blue.offset = 0;
180 var->blue.length = 8;
181 var->transp.offset = 0;
182 var->transp.length = 0;
183 break;
184 case 16: /* RGBA 5551 */
185 if (var->transp.length) {
186 var->red.offset = 0;
187 var->red.length = 5;
188 var->green.offset = 5;
189 var->green.length = 5;
190 var->blue.offset = 10;
191 var->blue.length = 5;
192 var->transp.offset = 15;
193 var->transp.length = 1;
194 } else { /* RGB 565 */
195 var->red.offset = 0;
196 var->red.length = 5;
197 var->green.offset = 5;
198 var->green.length = 6;
199 var->blue.offset = 11;
200 var->blue.length = 5;
201 var->transp.offset = 0;
202 var->transp.length = 0;
203 }
204 break;
205 case 24: /* RGB 888 */
206 var->red.offset = 0;
207 var->red.length = 8;
208 var->green.offset = 8;
209 var->green.length = 8;
210 var->blue.offset = 16;
211 var->blue.length = 8;
212 var->transp.offset = 0;
213 var->transp.length = 0;
214 break;
215 case 32: /* RGBA 8888 */
216 var->red.offset = 0;
217 var->red.length = 8;
218 var->green.offset = 8;
219 var->green.length = 8;
220 var->blue.offset = 16;
221 var->blue.length = 8;
222 var->transp.offset = 24;
223 var->transp.length = 8;
224 break;
225 }
226 var->red.msb_right = 0;
227 var->green.msb_right = 0;
228 var->blue.msb_right = 0;
229 var->transp.msb_right = 0;
230
231 return 0;
232 }
233
234 /* This routine actually sets the video mode. It's in here where we
235 * the hardware state info->par and fix which can be affected by the
236 * change in par. For this driver it doesn't do much.
237 */
vfb_set_par(struct fb_info * info)238 static int vfb_set_par(struct fb_info *info)
239 {
240 switch (info->var.bits_per_pixel) {
241 case 1:
242 info->fix.visual = FB_VISUAL_MONO01;
243 break;
244 case 8:
245 info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
246 break;
247 case 16:
248 case 24:
249 case 32:
250 info->fix.visual = FB_VISUAL_TRUECOLOR;
251 break;
252 }
253
254 info->fix.line_length = get_line_length(info->var.xres_virtual,
255 info->var.bits_per_pixel);
256
257 return 0;
258 }
259
260 /*
261 * Set a single color register. The values supplied are already
262 * rounded down to the hardware's capabilities (according to the
263 * entries in the var structure). Return != 0 for invalid regno.
264 */
265
vfb_setcolreg(u_int regno,u_int red,u_int green,u_int blue,u_int transp,struct fb_info * info)266 static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
267 u_int transp, struct fb_info *info)
268 {
269 if (regno >= 256) /* no. of hw registers */
270 return 1;
271 /*
272 * Program hardware... do anything you want with transp
273 */
274
275 /* grayscale works only partially under directcolor */
276 if (info->var.grayscale) {
277 /* grayscale = 0.30*R + 0.59*G + 0.11*B */
278 red = green = blue =
279 (red * 77 + green * 151 + blue * 28) >> 8;
280 }
281
282 /* Directcolor:
283 * var->{color}.offset contains start of bitfield
284 * var->{color}.length contains length of bitfield
285 * {hardwarespecific} contains width of RAMDAC
286 * cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset)
287 * RAMDAC[X] is programmed to (red, green, blue)
288 *
289 * Pseudocolor:
290 * var->{color}.offset is 0 unless the palette index takes less than
291 * bits_per_pixel bits and is stored in the upper
292 * bits of the pixel value
293 * var->{color}.length is set so that 1 << length is the number of available
294 * palette entries
295 * cmap is not used
296 * RAMDAC[X] is programmed to (red, green, blue)
297 *
298 * Truecolor:
299 * does not use DAC. Usually 3 are present.
300 * var->{color}.offset contains start of bitfield
301 * var->{color}.length contains length of bitfield
302 * cmap is programmed to (red << red.offset) | (green << green.offset) |
303 * (blue << blue.offset) | (transp << transp.offset)
304 * RAMDAC does not exist
305 */
306 #define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
307 switch (info->fix.visual) {
308 case FB_VISUAL_TRUECOLOR:
309 case FB_VISUAL_PSEUDOCOLOR:
310 red = CNVT_TOHW(red, info->var.red.length);
311 green = CNVT_TOHW(green, info->var.green.length);
312 blue = CNVT_TOHW(blue, info->var.blue.length);
313 transp = CNVT_TOHW(transp, info->var.transp.length);
314 break;
315 case FB_VISUAL_DIRECTCOLOR:
316 red = CNVT_TOHW(red, 8); /* expect 8 bit DAC */
317 green = CNVT_TOHW(green, 8);
318 blue = CNVT_TOHW(blue, 8);
319 /* hey, there is bug in transp handling... */
320 transp = CNVT_TOHW(transp, 8);
321 break;
322 }
323 #undef CNVT_TOHW
324 /* Truecolor has hardware independent palette */
325 if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
326 u32 v;
327
328 if (regno >= 16)
329 return 1;
330
331 v = (red << info->var.red.offset) |
332 (green << info->var.green.offset) |
333 (blue << info->var.blue.offset) |
334 (transp << info->var.transp.offset);
335 switch (info->var.bits_per_pixel) {
336 case 8:
337 break;
338 case 16:
339 ((u32 *) (info->pseudo_palette))[regno] = v;
340 break;
341 case 24:
342 case 32:
343 ((u32 *) (info->pseudo_palette))[regno] = v;
344 break;
345 }
346 return 0;
347 }
348 return 0;
349 }
350
351 /*
352 * Pan or Wrap the Display
353 *
354 * This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag
355 */
356
vfb_pan_display(struct fb_var_screeninfo * var,struct fb_info * info)357 static int vfb_pan_display(struct fb_var_screeninfo *var,
358 struct fb_info *info)
359 {
360 if (var->vmode & FB_VMODE_YWRAP) {
361 if (var->yoffset >= info->var.yres_virtual ||
362 var->xoffset)
363 return -EINVAL;
364 } else {
365 if (var->xoffset + info->var.xres > info->var.xres_virtual ||
366 var->yoffset + info->var.yres > info->var.yres_virtual)
367 return -EINVAL;
368 }
369 info->var.xoffset = var->xoffset;
370 info->var.yoffset = var->yoffset;
371 if (var->vmode & FB_VMODE_YWRAP)
372 info->var.vmode |= FB_VMODE_YWRAP;
373 else
374 info->var.vmode &= ~FB_VMODE_YWRAP;
375 return 0;
376 }
377
378 /*
379 * Most drivers don't need their own mmap function
380 */
381
vfb_mmap(struct fb_info * info,struct vm_area_struct * vma)382 static int vfb_mmap(struct fb_info *info,
383 struct vm_area_struct *vma)
384 {
385 vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
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 */
vfb_setup(char * options)395 static 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
vfb_probe(struct platform_device * dev)426 static 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->flags |= FBINFO_VIRTFB;
443 info->screen_buffer = videomemory;
444 info->fbops = &vfb_ops;
445
446 if (!fb_find_mode(&info->var, info, mode_option,
447 NULL, 0, &vfb_default, 8)){
448 fb_err(info, "Unable to find usable video mode.\n");
449 retval = -EINVAL;
450 goto err1;
451 }
452
453 vfb_fix.smem_start = (unsigned long) videomemory;
454 vfb_fix.smem_len = videomemorysize;
455 info->fix = vfb_fix;
456 info->pseudo_palette = info->par;
457 info->par = NULL;
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;
473 err2:
474 fb_dealloc_cmap(&info->cmap);
475 err1:
476 framebuffer_release(info);
477 err:
478 vfree(videomemory);
479 return retval;
480 }
481
vfb_remove(struct platform_device * dev)482 static void 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 }
493
494 static struct platform_driver vfb_driver = {
495 .probe = vfb_probe,
496 .remove_new = vfb_remove,
497 .driver = {
498 .name = "vfb",
499 },
500 };
501
502 static struct platform_device *vfb_device;
503
vfb_init(void)504 static int __init vfb_init(void)
505 {
506 int ret = 0;
507
508 #ifndef MODULE
509 char *option = NULL;
510
511 if (fb_get_options("vfb", &option))
512 return -ENODEV;
513 vfb_setup(option);
514 #endif
515
516 if (!vfb_enable)
517 return -ENXIO;
518
519 ret = platform_driver_register(&vfb_driver);
520
521 if (!ret) {
522 vfb_device = platform_device_alloc("vfb", 0);
523
524 if (vfb_device)
525 ret = platform_device_add(vfb_device);
526 else
527 ret = -ENOMEM;
528
529 if (ret) {
530 platform_device_put(vfb_device);
531 platform_driver_unregister(&vfb_driver);
532 }
533 }
534
535 return ret;
536 }
537
538 module_init(vfb_init);
539
540 #ifdef MODULE
vfb_exit(void)541 static void __exit vfb_exit(void)
542 {
543 platform_device_unregister(vfb_device);
544 platform_driver_unregister(&vfb_driver);
545 }
546
547 module_exit(vfb_exit);
548
549 MODULE_DESCRIPTION("Virtual Frame Buffer driver");
550 MODULE_LICENSE("GPL");
551 #endif /* MODULE */
552