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 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 98 static 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 */ 115 116 static 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 */ 240 static 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 */ 267 268 static 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 */ 358 359 static 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 */ 383 384 static 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 */ 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(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; 473 err2: 474 fb_dealloc_cmap(&info->cmap); 475 err1: 476 framebuffer_release(info); 477 err: 478 vfree(videomemory); 479 return retval; 480 } 481 482 static 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 } 494 495 static struct platform_driver vfb_driver = { 496 .probe = vfb_probe, 497 .remove = vfb_remove, 498 .driver = { 499 .name = "vfb", 500 }, 501 }; 502 503 static struct platform_device *vfb_device; 504 505 static 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 } 538 539 module_init(vfb_init); 540 541 #ifdef MODULE 542 static void __exit vfb_exit(void) 543 { 544 platform_device_unregister(vfb_device); 545 platform_driver_unregister(&vfb_driver); 546 } 547 548 module_exit(vfb_exit); 549 550 MODULE_LICENSE("GPL"); 551 #endif /* MODULE */ 552