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