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 info->fix.line_length = get_line_length(info->var.xres_virtual, 243 info->var.bits_per_pixel); 244 return 0; 245 } 246 247 /* 248 * Set a single color register. The values supplied are already 249 * rounded down to the hardware's capabilities (according to the 250 * entries in the var structure). Return != 0 for invalid regno. 251 */ 252 253 static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue, 254 u_int transp, struct fb_info *info) 255 { 256 if (regno >= 256) /* no. of hw registers */ 257 return 1; 258 /* 259 * Program hardware... do anything you want with transp 260 */ 261 262 /* grayscale works only partially under directcolor */ 263 if (info->var.grayscale) { 264 /* grayscale = 0.30*R + 0.59*G + 0.11*B */ 265 red = green = blue = 266 (red * 77 + green * 151 + blue * 28) >> 8; 267 } 268 269 /* Directcolor: 270 * var->{color}.offset contains start of bitfield 271 * var->{color}.length contains length of bitfield 272 * {hardwarespecific} contains width of RAMDAC 273 * cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset) 274 * RAMDAC[X] is programmed to (red, green, blue) 275 * 276 * Pseudocolor: 277 * var->{color}.offset is 0 unless the palette index takes less than 278 * bits_per_pixel bits and is stored in the upper 279 * bits of the pixel value 280 * var->{color}.length is set so that 1 << length is the number of available 281 * palette entries 282 * cmap is not used 283 * RAMDAC[X] is programmed to (red, green, blue) 284 * 285 * Truecolor: 286 * does not use DAC. Usually 3 are present. 287 * var->{color}.offset contains start of bitfield 288 * var->{color}.length contains length of bitfield 289 * cmap is programmed to (red << red.offset) | (green << green.offset) | 290 * (blue << blue.offset) | (transp << transp.offset) 291 * RAMDAC does not exist 292 */ 293 #define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16) 294 switch (info->fix.visual) { 295 case FB_VISUAL_TRUECOLOR: 296 case FB_VISUAL_PSEUDOCOLOR: 297 red = CNVT_TOHW(red, info->var.red.length); 298 green = CNVT_TOHW(green, info->var.green.length); 299 blue = CNVT_TOHW(blue, info->var.blue.length); 300 transp = CNVT_TOHW(transp, info->var.transp.length); 301 break; 302 case FB_VISUAL_DIRECTCOLOR: 303 red = CNVT_TOHW(red, 8); /* expect 8 bit DAC */ 304 green = CNVT_TOHW(green, 8); 305 blue = CNVT_TOHW(blue, 8); 306 /* hey, there is bug in transp handling... */ 307 transp = CNVT_TOHW(transp, 8); 308 break; 309 } 310 #undef CNVT_TOHW 311 /* Truecolor has hardware independent palette */ 312 if (info->fix.visual == FB_VISUAL_TRUECOLOR) { 313 u32 v; 314 315 if (regno >= 16) 316 return 1; 317 318 v = (red << info->var.red.offset) | 319 (green << info->var.green.offset) | 320 (blue << info->var.blue.offset) | 321 (transp << info->var.transp.offset); 322 switch (info->var.bits_per_pixel) { 323 case 8: 324 break; 325 case 16: 326 ((u32 *) (info->pseudo_palette))[regno] = v; 327 break; 328 case 24: 329 case 32: 330 ((u32 *) (info->pseudo_palette))[regno] = v; 331 break; 332 } 333 return 0; 334 } 335 return 0; 336 } 337 338 /* 339 * Pan or Wrap the Display 340 * 341 * This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag 342 */ 343 344 static int vfb_pan_display(struct fb_var_screeninfo *var, 345 struct fb_info *info) 346 { 347 if (var->vmode & FB_VMODE_YWRAP) { 348 if (var->yoffset >= info->var.yres_virtual || 349 var->xoffset) 350 return -EINVAL; 351 } else { 352 if (var->xoffset + info->var.xres > info->var.xres_virtual || 353 var->yoffset + info->var.yres > info->var.yres_virtual) 354 return -EINVAL; 355 } 356 info->var.xoffset = var->xoffset; 357 info->var.yoffset = var->yoffset; 358 if (var->vmode & FB_VMODE_YWRAP) 359 info->var.vmode |= FB_VMODE_YWRAP; 360 else 361 info->var.vmode &= ~FB_VMODE_YWRAP; 362 return 0; 363 } 364 365 /* 366 * Most drivers don't need their own mmap function 367 */ 368 369 static int vfb_mmap(struct fb_info *info, 370 struct vm_area_struct *vma) 371 { 372 return remap_vmalloc_range(vma, (void *)info->fix.smem_start, vma->vm_pgoff); 373 } 374 375 #ifndef MODULE 376 /* 377 * The virtual framebuffer driver is only enabled if explicitly 378 * requested by passing 'video=vfb:' (or any actual options). 379 */ 380 static int __init vfb_setup(char *options) 381 { 382 char *this_opt; 383 384 vfb_enable = 0; 385 386 if (!options) 387 return 1; 388 389 vfb_enable = 1; 390 391 if (!*options) 392 return 1; 393 394 while ((this_opt = strsep(&options, ",")) != NULL) { 395 if (!*this_opt) 396 continue; 397 /* Test disable for backwards compatibility */ 398 if (!strcmp(this_opt, "disable")) 399 vfb_enable = 0; 400 else 401 mode_option = this_opt; 402 } 403 return 1; 404 } 405 #endif /* MODULE */ 406 407 /* 408 * Initialisation 409 */ 410 411 static int vfb_probe(struct platform_device *dev) 412 { 413 struct fb_info *info; 414 unsigned int size = PAGE_ALIGN(videomemorysize); 415 int retval = -ENOMEM; 416 417 /* 418 * For real video cards we use ioremap. 419 */ 420 if (!(videomemory = vmalloc_32_user(size))) 421 return retval; 422 423 info = framebuffer_alloc(sizeof(u32) * 256, &dev->dev); 424 if (!info) 425 goto err; 426 427 info->screen_base = (char __iomem *)videomemory; 428 info->fbops = &vfb_ops; 429 430 if (!fb_find_mode(&info->var, info, mode_option, 431 NULL, 0, &vfb_default, 8)){ 432 fb_err(info, "Unable to find usable video mode.\n"); 433 retval = -EINVAL; 434 goto err1; 435 } 436 437 vfb_fix.smem_start = (unsigned long) videomemory; 438 vfb_fix.smem_len = videomemorysize; 439 info->fix = vfb_fix; 440 info->pseudo_palette = info->par; 441 info->par = NULL; 442 info->flags = FBINFO_FLAG_DEFAULT; 443 444 retval = fb_alloc_cmap(&info->cmap, 256, 0); 445 if (retval < 0) 446 goto err1; 447 448 retval = register_framebuffer(info); 449 if (retval < 0) 450 goto err2; 451 platform_set_drvdata(dev, info); 452 453 fb_info(info, "Virtual frame buffer device, using %ldK of video memory\n", 454 videomemorysize >> 10); 455 return 0; 456 err2: 457 fb_dealloc_cmap(&info->cmap); 458 err1: 459 framebuffer_release(info); 460 err: 461 vfree(videomemory); 462 return retval; 463 } 464 465 static int vfb_remove(struct platform_device *dev) 466 { 467 struct fb_info *info = platform_get_drvdata(dev); 468 469 if (info) { 470 unregister_framebuffer(info); 471 vfree(videomemory); 472 fb_dealloc_cmap(&info->cmap); 473 framebuffer_release(info); 474 } 475 return 0; 476 } 477 478 static struct platform_driver vfb_driver = { 479 .probe = vfb_probe, 480 .remove = vfb_remove, 481 .driver = { 482 .name = "vfb", 483 }, 484 }; 485 486 static struct platform_device *vfb_device; 487 488 static int __init vfb_init(void) 489 { 490 int ret = 0; 491 492 #ifndef MODULE 493 char *option = NULL; 494 495 if (fb_get_options("vfb", &option)) 496 return -ENODEV; 497 vfb_setup(option); 498 #endif 499 500 if (!vfb_enable) 501 return -ENXIO; 502 503 ret = platform_driver_register(&vfb_driver); 504 505 if (!ret) { 506 vfb_device = platform_device_alloc("vfb", 0); 507 508 if (vfb_device) 509 ret = platform_device_add(vfb_device); 510 else 511 ret = -ENOMEM; 512 513 if (ret) { 514 platform_device_put(vfb_device); 515 platform_driver_unregister(&vfb_driver); 516 } 517 } 518 519 return ret; 520 } 521 522 module_init(vfb_init); 523 524 #ifdef MODULE 525 static void __exit vfb_exit(void) 526 { 527 platform_device_unregister(vfb_device); 528 platform_driver_unregister(&vfb_driver); 529 } 530 531 module_exit(vfb_exit); 532 533 MODULE_LICENSE("GPL"); 534 #endif /* MODULE */ 535