drivers/video/vfb.c

   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
  39 /**********************************************************************
  40  *
  41  * Memory management
  42  *
  43  **********************************************************************/
  44 static void *rvmalloc(unsigned long size)
  45 {
  46         void *mem;
  47         unsigned long adr;
  48
  49         size = PAGE_ALIGN(size);
  50         mem = vmalloc_32(size);
  51         if (!mem)
  52                 return NULL;
  53
  54         memset(mem, 0, size); /* Clear the ram out, no junk to the user */
  55         adr = (unsigned long) mem;
  56         while (size > 0) {
  57                 SetPageReserved(vmalloc_to_page((void *)adr));
  58                 adr += PAGE_SIZE;
  59                 size -= PAGE_SIZE;
  60         }
  61
  62         return mem;
  63 }
  64
  65 static void rvfree(void *mem, unsigned long size)
  66 {
  67         unsigned long adr;
  68
  69         if (!mem)
  70                 return;
  71
  72         adr = (unsigned long) mem;
  73         while ((long) size > 0) {
  74                 ClearPageReserved(vmalloc_to_page((void *)adr));
  75                 adr += PAGE_SIZE;
  76                 size -= PAGE_SIZE;
  77         }
  78         vfree(mem);
  79 }
  80
  81 static struct fb_var_screeninfo vfb_default = {
  82         .xres =         640,
  83         .yres =         480,
  84         .xres_virtual = 640,
  85         .yres_virtual = 480,
  86         .bits_per_pixel = 8,
  87         .red =          { 0, 8, 0 },
  88         .green =        { 0, 8, 0 },
  89         .blue =         { 0, 8, 0 },
  90         .activate =     FB_ACTIVATE_TEST,
  91         .height =       -1,
  92         .width =        -1,
  93         .pixclock =     20000,
  94         .left_margin =  64,
  95         .right_margin = 64,
  96         .upper_margin = 32,
  97         .lower_margin = 32,
  98         .hsync_len =    64,
  99         .vsync_len =    2,
 100         .vmode =        FB_VMODE_NONINTERLACED,
 101 };
 102
 103 static struct fb_fix_screeninfo vfb_fix = {
 104         .id =           "Virtual FB",
 105         .type =         FB_TYPE_PACKED_PIXELS,
 106         .visual =       FB_VISUAL_PSEUDOCOLOR,
 107         .xpanstep =     1,
 108         .ypanstep =     1,
 109         .ywrapstep =    1,
 110         .accel =        FB_ACCEL_NONE,
 111 };
 112
 113 static bool vfb_enable __initdata = 0;  /* disabled by default */
 114 module_param(vfb_enable, bool, 0);
 115
 116 static int vfb_check_var(struct fb_var_screeninfo *var,
 117                          struct fb_info *info);
 118 static int vfb_set_par(struct fb_info *info);
 119 static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
 120                          u_int transp, struct fb_info *info);
 121 static int vfb_pan_display(struct fb_var_screeninfo *var,
 122                            struct fb_info *info);
 123 static int vfb_mmap(struct fb_info *info,
 124                     struct vm_area_struct *vma);
 125
 126 static struct fb_ops vfb_ops = {
 127         .fb_read        = fb_sys_read,
 128         .fb_write       = fb_sys_write,
 129         .fb_check_var   = vfb_check_var,
 130         .fb_set_par     = vfb_set_par,
 131         .fb_setcolreg   = vfb_setcolreg,
 132         .fb_pan_display = vfb_pan_display,
 133         .fb_fillrect    = sys_fillrect,
 134         .fb_copyarea    = sys_copyarea,
 135         .fb_imageblit   = sys_imageblit,
 136         .fb_mmap        = vfb_mmap,
 137 };
 138
 139     /*
 140      *  Internal routines
 141      */
 142
 143 static u_long get_line_length(int xres_virtual, int bpp)
 144 {
 145         u_long length;
 146
 147         length = xres_virtual * bpp;
 148         length = (length + 31) & ~31;
 149         length >>= 3;
 150         return (length);
 151 }
 152
 153     /*
 154      *  Setting the video mode has been split into two parts.
 155      *  First part, xxxfb_check_var, must not write anything
 156      *  to hardware, it should only verify and adjust var.
 157      *  This means it doesn't alter par but it does use hardware
 158      *  data from it to check this var.
 159      */
 160
 161 static int vfb_check_var(struct fb_var_screeninfo *var,
 162                          struct fb_info *info)
 163 {
 164         u_long line_length;
 165
 166         /*
 167          *  FB_VMODE_CONUPDATE and FB_VMODE_SMOOTH_XPAN are equal!
 168          *  as FB_VMODE_SMOOTH_XPAN is only used internally
 169          */
 170
 171         if (var->vmode & FB_VMODE_CONUPDATE) {
 172                 var->vmode |= FB_VMODE_YWRAP;
 173                 var->xoffset = info->var.xoffset;
 174                 var->yoffset = info->var.yoffset;
 175         }
 176
 177         /*
 178          *  Some very basic checks
 179          */
 180         if (!var->xres)
 181                 var->xres = 1;
 182         if (!var->yres)
 183                 var->yres = 1;
 184         if (var->xres > var->xres_virtual)
 185                 var->xres_virtual = var->xres;
 186         if (var->yres > var->yres_virtual)
 187                 var->yres_virtual = var->yres;
 188         if (var->bits_per_pixel <= 1)
 189                 var->bits_per_pixel = 1;
 190         else if (var->bits_per_pixel <= 8)
 191                 var->bits_per_pixel = 8;
 192         else if (var->bits_per_pixel <= 16)
 193                 var->bits_per_pixel = 16;
 194         else if (var->bits_per_pixel <= 24)
 195                 var->bits_per_pixel = 24;
 196         else if (var->bits_per_pixel <= 32)
 197                 var->bits_per_pixel = 32;
 198         else
 199                 return -EINVAL;
 200
 201         if (var->xres_virtual < var->xoffset + var->xres)
 202                 var->xres_virtual = var->xoffset + var->xres;
 203         if (var->yres_virtual < var->yoffset + var->yres)
 204                 var->yres_virtual = var->yoffset + var->yres;
 205
 206         /*
 207          *  Memory limit
 208          */
 209         line_length =
 210             get_line_length(var->xres_virtual, var->bits_per_pixel);
 211         if (line_length * var->yres_virtual > videomemorysize)
 212                 return -ENOMEM;
 213
 214         /*
 215          * Now that we checked it we alter var. The reason being is that the video
 216          * mode passed in might not work but slight changes to it might make it
 217          * work. This way we let the user know what is acceptable.
 218          */
 219         switch (var->bits_per_pixel) {
 220         case 1:
 221         case 8:
 222                 var->red.offset = 0;
 223                 var->red.length = 8;
 224                 var->green.offset = 0;
 225                 var->green.length = 8;
 226                 var->blue.offset = 0;
 227                 var->blue.length = 8;
 228                 var->transp.offset = 0;
 229                 var->transp.length = 0;
 230                 break;
 231         case 16:                /* RGBA 5551 */
 232                 if (var->transp.length) {
 233                         var->red.offset = 0;
 234                         var->red.length = 5;
 235                         var->green.offset = 5;
 236                         var->green.length = 5;
 237                         var->blue.offset = 10;
 238                         var->blue.length = 5;
 239                         var->transp.offset = 15;
 240                         var->transp.length = 1;
 241                 } else {        /* RGB 565 */
 242                         var->red.offset = 0;
 243                         var->red.length = 5;
 244                         var->green.offset = 5;
 245                         var->green.length = 6;
 246                         var->blue.offset = 11;
 247                         var->blue.length = 5;
 248                         var->transp.offset = 0;
 249                         var->transp.length = 0;
 250                 }
 251                 break;
 252         case 24:                /* RGB 888 */
 253                 var->red.offset = 0;
 254                 var->red.length = 8;
 255                 var->green.offset = 8;
 256                 var->green.length = 8;
 257                 var->blue.offset = 16;
 258                 var->blue.length = 8;
 259                 var->transp.offset = 0;
 260                 var->transp.length = 0;
 261                 break;
 262         case 32:                /* RGBA 8888 */
 263                 var->red.offset = 0;
 264                 var->red.length = 8;
 265                 var->green.offset = 8;
 266                 var->green.length = 8;
 267                 var->blue.offset = 16;
 268                 var->blue.length = 8;
 269                 var->transp.offset = 24;
 270                 var->transp.length = 8;
 271                 break;
 272         }
 273         var->red.msb_right = 0;
 274         var->green.msb_right = 0;
 275         var->blue.msb_right = 0;
 276         var->transp.msb_right = 0;
 277
 278         return 0;
 279 }
 280
 281 /* This routine actually sets the video mode. It's in here where we
 282  * the hardware state info->par and fix which can be affected by the
 283  * change in par. For this driver it doesn't do much.
 284  */
 285 static int vfb_set_par(struct fb_info *info)
 286 {
 287         info->fix.line_length = get_line_length(info->var.xres_virtual,
 288                                                 info->var.bits_per_pixel);
 289         return 0;
 290 }
 291
 292     /*
 293      *  Set a single color register. The values supplied are already
 294      *  rounded down to the hardware's capabilities (according to the
 295      *  entries in the var structure). Return != 0 for invalid regno.
 296      */
 297
 298 static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
 299                          u_int transp, struct fb_info *info)
 300 {
 301         if (regno >= 256)       /* no. of hw registers */
 302                 return 1;
 303         /*
 304          * Program hardware... do anything you want with transp
 305          */
 306
 307         /* grayscale works only partially under directcolor */
 308         if (info->var.grayscale) {
 309                 /* grayscale = 0.30*R + 0.59*G + 0.11*B */
 310                 red = green = blue =
 311                     (red * 77 + green * 151 + blue * 28) >> 8;
 312         }
 313
 314         /* Directcolor:
 315          *   var->{color}.offset contains start of bitfield
 316          *   var->{color}.length contains length of bitfield
 317          *   {hardwarespecific} contains width of RAMDAC
 318          *   cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset)
 319          *   RAMDAC[X] is programmed to (red, green, blue)
 320          *
 321          * Pseudocolor:
 322          *    var->{color}.offset is 0 unless the palette index takes less than
 323          *                        bits_per_pixel bits and is stored in the upper
 324          *                        bits of the pixel value
 325          *    var->{color}.length is set so that 1 << length is the number of available
 326          *                        palette entries
 327          *    cmap is not used
 328          *    RAMDAC[X] is programmed to (red, green, blue)
 329          *
 330          * Truecolor:
 331          *    does not use DAC. Usually 3 are present.
 332          *    var->{color}.offset contains start of bitfield
 333          *    var->{color}.length contains length of bitfield
 334          *    cmap is programmed to (red << red.offset) | (green << green.offset) |
 335          *                      (blue << blue.offset) | (transp << transp.offset)
 336          *    RAMDAC does not exist
 337          */
 338 #define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
 339         switch (info->fix.visual) {
 340         case FB_VISUAL_TRUECOLOR:
 341         case FB_VISUAL_PSEUDOCOLOR:
 342                 red = CNVT_TOHW(red, info->var.red.length);
 343                 green = CNVT_TOHW(green, info->var.green.length);
 344                 blue = CNVT_TOHW(blue, info->var.blue.length);
 345                 transp = CNVT_TOHW(transp, info->var.transp.length);
 346                 break;
 347         case FB_VISUAL_DIRECTCOLOR:
 348                 red = CNVT_TOHW(red, 8);        /* expect 8 bit DAC */
 349                 green = CNVT_TOHW(green, 8);
 350                 blue = CNVT_TOHW(blue, 8);
 351                 /* hey, there is bug in transp handling... */
 352                 transp = CNVT_TOHW(transp, 8);
 353                 break;
 354         }
 355 #undef CNVT_TOHW
 356         /* Truecolor has hardware independent palette */
 357         if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
 358                 u32 v;
 359
 360                 if (regno >= 16)
 361                         return 1;
 362
 363                 v = (red << info->var.red.offset) |
 364                     (green << info->var.green.offset) |
 365                     (blue << info->var.blue.offset) |
 366                     (transp << info->var.transp.offset);
 367                 switch (info->var.bits_per_pixel) {
 368                 case 8:
 369                         break;
 370                 case 16:
 371                         ((u32 *) (info->pseudo_palette))[regno] = v;
 372                         break;
 373                 case 24:
 374                 case 32:
 375                         ((u32 *) (info->pseudo_palette))[regno] = v;
 376                         break;
 377                 }
 378                 return 0;
 379         }
 380         return 0;
 381 }
 382
 383     /*
 384      *  Pan or Wrap the Display
 385      *
 386      *  This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag
 387      */
 388
 389 static int vfb_pan_display(struct fb_var_screeninfo *var,
 390                            struct fb_info *info)
 391 {
 392         if (var->vmode & FB_VMODE_YWRAP) {
 393                 if (var->yoffset >= info->var.yres_virtual ||
 394                     var->xoffset)
 395                         return -EINVAL;
 396         } else {
 397                 if (var->xoffset + info->var.xres > info->var.xres_virtual ||
 398                     var->yoffset + info->var.yres > info->var.yres_virtual)
 399                         return -EINVAL;
 400         }
 401         info->var.xoffset = var->xoffset;
 402         info->var.yoffset = var->yoffset;
 403         if (var->vmode & FB_VMODE_YWRAP)
 404                 info->var.vmode |= FB_VMODE_YWRAP;
 405         else
 406                 info->var.vmode &= ~FB_VMODE_YWRAP;
 407         return 0;
 408 }
 409
 410     /*
 411      *  Most drivers don't need their own mmap function
 412      */
 413
 414 static int vfb_mmap(struct fb_info *info,
 415                     struct vm_area_struct *vma)
 416 {
 417         unsigned long start = vma->vm_start;
 418         unsigned long size = vma->vm_end - vma->vm_start;
 419         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
 420         unsigned long page, pos;
 421
 422         if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
 423                 return -EINVAL;
 424         if (size > info->fix.smem_len)
 425                 return -EINVAL;
 426         if (offset > info->fix.smem_len - size)
 427                 return -EINVAL;
 428
 429         pos = (unsigned long)info->fix.smem_start + offset;
 430
 431         while (size > 0) {
 432                 page = vmalloc_to_pfn((void *)pos);
 433                 if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED)) {
 434                         return -EAGAIN;
 435                 }
 436                 start += PAGE_SIZE;
 437                 pos += PAGE_SIZE;
 438                 if (size > PAGE_SIZE)
 439                         size -= PAGE_SIZE;
 440                 else
 441                         size = 0;
 442         }
 443
 444         return 0;
 445
 446 }
 447
 448 #ifndef MODULE
 449 /*
 450  * The virtual framebuffer driver is only enabled if explicitly
 451  * requested by passing 'video=vfb:' (or any actual options).
 452  */
 453 static int __init vfb_setup(char *options)
 454 {
 455         char *this_opt;
 456
 457         vfb_enable = 0;
 458
 459         if (!options)
 460                 return 1;
 461
 462         vfb_enable = 1;
 463
 464         if (!*options)
 465                 return 1;
 466
 467         while ((this_opt = strsep(&options, ",")) != NULL) {
 468                 if (!*this_opt)
 469                         continue;
 470                 /* Test disable for backwards compatibility */
 471                 if (!strcmp(this_opt, "disable"))
 472                         vfb_enable = 0;
 473         }
 474         return 1;
 475 }
 476 #endif  /*  MODULE  */
 477
 478     /*
 479      *  Initialisation
 480      */
 481
 482 static int vfb_probe(struct platform_device *dev)
 483 {
 484         struct fb_info *info;
 485         int retval = -ENOMEM;
 486
 487         /*
 488          * For real video cards we use ioremap.
 489          */
 490         if (!(videomemory = rvmalloc(videomemorysize)))
 491                 return retval;
 492
 493         /*
 494          * VFB must clear memory to prevent kernel info
 495          * leakage into userspace
 496          * VGA-based drivers MUST NOT clear memory if
 497          * they want to be able to take over vgacon
 498          */
 499         memset(videomemory, 0, videomemorysize);
 500
 501         info = framebuffer_alloc(sizeof(u32) * 256, &dev->dev);
 502         if (!info)
 503                 goto err;
 504
 505         info->screen_base = (char __iomem *)videomemory;
 506         info->fbops = &vfb_ops;
 507
 508         retval = fb_find_mode(&info->var, info, NULL,
 509                               NULL, 0, NULL, 8);
 510
 511         if (!retval || (retval == 4))
 512                 info->var = vfb_default;
 513         vfb_fix.smem_start = (unsigned long) videomemory;
 514         vfb_fix.smem_len = videomemorysize;
 515         info->fix = vfb_fix;
 516         info->pseudo_palette = info->par;
 517         info->par = NULL;
 518         info->flags = FBINFO_FLAG_DEFAULT;
 519
 520         retval = fb_alloc_cmap(&info->cmap, 256, 0);
 521         if (retval < 0)
 522                 goto err1;
 523
 524         retval = register_framebuffer(info);
 525         if (retval < 0)
 526                 goto err2;
 527         platform_set_drvdata(dev, info);
 528
 529         fb_info(info, "Virtual frame buffer device, using %ldK of video memory\n",
 530                 videomemorysize >> 10);
 531         return 0;
 532 err2:
 533         fb_dealloc_cmap(&info->cmap);
 534 err1:
 535         framebuffer_release(info);
 536 err:
 537         rvfree(videomemory, videomemorysize);
 538         return retval;
 539 }
 540
 541 static int vfb_remove(struct platform_device *dev)
 542 {
 543         struct fb_info *info = platform_get_drvdata(dev);
 544
 545         if (info) {
 546                 unregister_framebuffer(info);
 547                 rvfree(videomemory, videomemorysize);
 548                 fb_dealloc_cmap(&info->cmap);
 549                 framebuffer_release(info);
 550         }
 551         return 0;
 552 }
 553
 554 static struct platform_driver vfb_driver = {
 555         .probe  = vfb_probe,
 556         .remove = vfb_remove,
 557         .driver = {
 558                 .name   = "vfb",
 559         },
 560 };
 561
 562 static struct platform_device *vfb_device;
 563
 564 static int __init vfb_init(void)
 565 {
 566         int ret = 0;
 567
 568 #ifndef MODULE
 569         char *option = NULL;
 570
 571         if (fb_get_options("vfb", &option))
 572                 return -ENODEV;
 573         vfb_setup(option);
 574 #endif
 575
 576         if (!vfb_enable)
 577                 return -ENXIO;
 578
 579         ret = platform_driver_register(&vfb_driver);
 580
 581         if (!ret) {
 582                 vfb_device = platform_device_alloc("vfb", 0);
 583
 584                 if (vfb_device)
 585                         ret = platform_device_add(vfb_device);
 586                 else
 587                         ret = -ENOMEM;
 588
 589                 if (ret) {
 590                         platform_device_put(vfb_device);
 591                         platform_driver_unregister(&vfb_driver);
 592                 }
 593         }
 594
 595         return ret;
 596 }
 597
 598 module_init(vfb_init);
 599
 600 #ifdef MODULE
 601 static void __exit vfb_exit(void)
 602 {
 603         platform_device_unregister(vfb_device);
 604         platform_driver_unregister(&vfb_driver);
 605 }
 606
 607 module_exit(vfb_exit);
 608
 609 MODULE_LICENSE("GPL");
 610 #endif                          /* MODULE */