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 | |
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 | |
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(xres_virtual: var->xres_virtual, bpp: 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 | */ |
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(xres_virtual: info->var.xres_virtual, |
255 | bpp: 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 | |
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 | |
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 | |
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, addr: (void *)info->fix.smem_start, pgoff: 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 | */ |
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 | |
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(size: sizeof(u32) * 256, dev: &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(var: &info->var, info, mode_option, |
447 | NULL, dbsize: 0, default_mode: &vfb_default, default_bpp: 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(cmap: &info->cmap, len: 256, transp: 0); |
460 | if (retval < 0) |
461 | goto err1; |
462 | |
463 | retval = register_framebuffer(fb_info: info); |
464 | if (retval < 0) |
465 | goto err2; |
466 | platform_set_drvdata(pdev: dev, data: 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(cmap: &info->cmap); |
475 | err1: |
476 | framebuffer_release(info); |
477 | err: |
478 | vfree(addr: videomemory); |
479 | return retval; |
480 | } |
481 | |
482 | static void vfb_remove(struct platform_device *dev) |
483 | { |
484 | struct fb_info *info = platform_get_drvdata(pdev: dev); |
485 | |
486 | if (info) { |
487 | unregister_framebuffer(fb_info: info); |
488 | vfree(addr: videomemory); |
489 | fb_dealloc_cmap(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 | |
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(name: "vfb" , option: &option)) |
512 | return -ENODEV; |
513 | vfb_setup(options: 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(name: "vfb" , id: 0); |
523 | |
524 | if (vfb_device) |
525 | ret = platform_device_add(pdev: vfb_device); |
526 | else |
527 | ret = -ENOMEM; |
528 | |
529 | if (ret) { |
530 | platform_device_put(pdev: 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 |
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_LICENSE("GPL" ); |
550 | #endif /* MODULE */ |
551 | |