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/tty.h>
  19 #include <linux/slab.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/delay.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/platform_device.h>
  24
  25 #include <asm/uaccess.h>
  26 #include <linux/fb.h>
  27 #include <linux/init.h>
  28
  29     /*
  30      *  RAM we reserve for the frame buffer. This defines the maximum screen
  31      *  size
  32      *
  33      *  The default can be overridden if the driver is compiled as a module
  34      */
  35
  36 #define VIDEOMEMSIZE    (1*1024*1024)   /* 1 MB */
  37
  38 static void *videomemory;
  39 static u_long videomemorysize = VIDEOMEMSIZE;
  40 module_param(videomemorysize, ulong, 0);
  41
  42 static struct fb_var_screeninfo vfb_default __initdata = {
  43         .xres =         640,
  44         .yres =         480,
  45         .xres_virtual = 640,
  46         .yres_virtual = 480,
  47         .bits_per_pixel = 8,
  48         .red =          { 0, 8, 0 },
  49         .green =        { 0, 8, 0 },
  50         .blue =         { 0, 8, 0 },
  51         .activate =     FB_ACTIVATE_TEST,
  52         .height =       -1,
  53         .width =        -1,
  54         .pixclock =     20000,
  55         .left_margin =  64,
  56         .right_margin = 64,
  57         .upper_margin = 32,
  58         .lower_margin = 32,
  59         .hsync_len =    64,
  60         .vsync_len =    2,
  61         .vmode =        FB_VMODE_NONINTERLACED,
  62 };
  63
  64 static struct fb_fix_screeninfo vfb_fix __initdata = {
  65         .id =           "Virtual FB",
  66         .type =         FB_TYPE_PACKED_PIXELS,
  67         .visual =       FB_VISUAL_PSEUDOCOLOR,
  68         .xpanstep =     1,
  69         .ypanstep =     1,
  70         .ywrapstep =    1,
  71         .accel =        FB_ACCEL_NONE,
  72 };
  73
  74 static int vfb_enable __initdata = 0;   /* disabled by default */
  75 module_param(vfb_enable, bool, 0);
  76
  77 static int vfb_check_var(struct fb_var_screeninfo *var,
  78                          struct fb_info *info);
  79 static int vfb_set_par(struct fb_info *info);
  80 static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
  81                          u_int transp, struct fb_info *info);
  82 static int vfb_pan_display(struct fb_var_screeninfo *var,
  83                            struct fb_info *info);
  84 static int vfb_mmap(struct fb_info *info,
  85                     struct vm_area_struct *vma);
  86
  87 static struct fb_ops vfb_ops = {
  88         .fb_check_var   = vfb_check_var,
  89         .fb_set_par     = vfb_set_par,
  90         .fb_setcolreg   = vfb_setcolreg,
  91         .fb_pan_display = vfb_pan_display,
  92         .fb_fillrect    = cfb_fillrect,
  93         .fb_copyarea    = cfb_copyarea,
  94         .fb_imageblit   = cfb_imageblit,
  95         .fb_mmap        = vfb_mmap,
  96 };
  97
  98     /*
  99      *  Internal routines
 100      */
 101
 102 static u_long get_line_length(int xres_virtual, int bpp)
 103 {
 104         u_long length;
 105
 106         length = xres_virtual * bpp;
 107         length = (length + 31) & ~31;
 108         length >>= 3;
 109         return (length);
 110 }
 111
 112     /*
 113      *  Setting the video mode has been split into two parts.
 114      *  First part, xxxfb_check_var, must not write anything
 115      *  to hardware, it should only verify and adjust var.
 116      *  This means it doesn't alter par but it does use hardware
 117      *  data from it to check this var.
 118      */
 119
 120 static int vfb_check_var(struct fb_var_screeninfo *var,
 121                          struct fb_info *info)
 122 {
 123         u_long line_length;
 124
 125         /*
 126          *  FB_VMODE_CONUPDATE and FB_VMODE_SMOOTH_XPAN are equal!
 127          *  as FB_VMODE_SMOOTH_XPAN is only used internally
 128          */
 129
 130         if (var->vmode & FB_VMODE_CONUPDATE) {
 131                 var->vmode |= FB_VMODE_YWRAP;
 132                 var->xoffset = info->var.xoffset;
 133                 var->yoffset = info->var.yoffset;
 134         }
 135
 136         /*
 137          *  Some very basic checks
 138          */
 139         if (!var->xres)
 140                 var->xres = 1;
 141         if (!var->yres)
 142                 var->yres = 1;
 143         if (var->xres > var->xres_virtual)
 144                 var->xres_virtual = var->xres;
 145         if (var->yres > var->yres_virtual)
 146                 var->yres_virtual = var->yres;
 147         if (var->bits_per_pixel <= 1)
 148                 var->bits_per_pixel = 1;
 149         else if (var->bits_per_pixel <= 8)
 150                 var->bits_per_pixel = 8;
 151         else if (var->bits_per_pixel <= 16)
 152                 var->bits_per_pixel = 16;
 153         else if (var->bits_per_pixel <= 24)
 154                 var->bits_per_pixel = 24;
 155         else if (var->bits_per_pixel <= 32)
 156                 var->bits_per_pixel = 32;
 157         else
 158                 return -EINVAL;
 159
 160         if (var->xres_virtual < var->xoffset + var->xres)
 161                 var->xres_virtual = var->xoffset + var->xres;
 162         if (var->yres_virtual < var->yoffset + var->yres)
 163                 var->yres_virtual = var->yoffset + var->yres;
 164
 165         /*
 166          *  Memory limit
 167          */
 168         line_length =
 169             get_line_length(var->xres_virtual, var->bits_per_pixel);
 170         if (line_length * var->yres_virtual > videomemorysize)
 171                 return -ENOMEM;
 172
 173         /*
 174          * Now that we checked it we alter var. The reason being is that the video
 175          * mode passed in might not work but slight changes to it might make it
 176          * work. This way we let the user know what is acceptable.
 177          */
 178         switch (var->bits_per_pixel) {
 179         case 1:
 180         case 8:
 181                 var->red.offset = 0;
 182                 var->red.length = 8;
 183                 var->green.offset = 0;
 184                 var->green.length = 8;
 185                 var->blue.offset = 0;
 186                 var->blue.length = 8;
 187                 var->transp.offset = 0;
 188                 var->transp.length = 0;
 189                 break;
 190         case 16:                /* RGBA 5551 */
 191                 if (var->transp.length) {
 192                         var->red.offset = 0;
 193                         var->red.length = 5;
 194                         var->green.offset = 5;
 195                         var->green.length = 5;
 196                         var->blue.offset = 10;
 197                         var->blue.length = 5;
 198                         var->transp.offset = 15;
 199                         var->transp.length = 1;
 200                 } else {        /* RGB 565 */
 201                         var->red.offset = 0;
 202                         var->red.length = 5;
 203                         var->green.offset = 5;
 204                         var->green.length = 6;
 205                         var->blue.offset = 11;
 206                         var->blue.length = 5;
 207                         var->transp.offset = 0;
 208                         var->transp.length = 0;
 209                 }
 210                 break;
 211         case 24:                /* RGB 888 */
 212                 var->red.offset = 0;
 213                 var->red.length = 8;
 214                 var->green.offset = 8;
 215                 var->green.length = 8;
 216                 var->blue.offset = 16;
 217                 var->blue.length = 8;
 218                 var->transp.offset = 0;
 219                 var->transp.length = 0;
 220                 break;
 221         case 32:                /* RGBA 8888 */
 222                 var->red.offset = 0;
 223                 var->red.length = 8;
 224                 var->green.offset = 8;
 225                 var->green.length = 8;
 226                 var->blue.offset = 16;
 227                 var->blue.length = 8;
 228                 var->transp.offset = 24;
 229                 var->transp.length = 8;
 230                 break;
 231         }
 232         var->red.msb_right = 0;
 233         var->green.msb_right = 0;
 234         var->blue.msb_right = 0;
 235         var->transp.msb_right = 0;
 236
 237         return 0;
 238 }
 239
 240 /* This routine actually sets the video mode. It's in here where we
 241  * the hardware state info->par and fix which can be affected by the
 242  * change in par. For this driver it doesn't do much.
 243  */
 244 static int vfb_set_par(struct fb_info *info)
 245 {
 246         info->fix.line_length = get_line_length(info->var.xres_virtual,
 247                                                 info->var.bits_per_pixel);
 248         return 0;
 249 }
 250
 251     /*
 252      *  Set a single color register. The values supplied are already
 253      *  rounded down to the hardware's capabilities (according to the
 254      *  entries in the var structure). Return != 0 for invalid regno.
 255      */
 256
 257 static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
 258                          u_int transp, struct fb_info *info)
 259 {
 260         if (regno >= 256)       /* no. of hw registers */
 261                 return 1;
 262         /*
 263          * Program hardware... do anything you want with transp
 264          */
 265
 266         /* grayscale works only partially under directcolor */
 267         if (info->var.grayscale) {
 268                 /* grayscale = 0.30*R + 0.59*G + 0.11*B */
 269                 red = green = blue =
 270                     (red * 77 + green * 151 + blue * 28) >> 8;
 271         }
 272
 273         /* Directcolor:
 274          *   var->{color}.offset contains start of bitfield
 275          *   var->{color}.length contains length of bitfield
 276          *   {hardwarespecific} contains width of RAMDAC
 277          *   cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset)
 278          *   RAMDAC[X] is programmed to (red, green, blue)
 279          *
 280          * Pseudocolor:
 281          *    uses offset = 0 && length = RAMDAC register width.
 282          *    var->{color}.offset is 0
 283          *    var->{color}.length contains widht of DAC
 284          *    cmap is not used
 285          *    RAMDAC[X] is programmed to (red, green, blue)
 286          * Truecolor:
 287          *    does not use DAC. Usually 3 are present.
 288          *    var->{color}.offset contains start of bitfield
 289          *    var->{color}.length contains length of bitfield
 290          *    cmap is programmed to (red << red.offset) | (green << green.offset) |
 291          *                      (blue << blue.offset) | (transp << transp.offset)
 292          *    RAMDAC does not exist
 293          */
 294 #define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
 295         switch (info->fix.visual) {
 296         case FB_VISUAL_TRUECOLOR:
 297         case FB_VISUAL_PSEUDOCOLOR:
 298                 red = CNVT_TOHW(red, info->var.red.length);
 299                 green = CNVT_TOHW(green, info->var.green.length);
 300                 blue = CNVT_TOHW(blue, info->var.blue.length);
 301                 transp = CNVT_TOHW(transp, info->var.transp.length);
 302                 break;
 303         case FB_VISUAL_DIRECTCOLOR:
 304                 red = CNVT_TOHW(red, 8);        /* expect 8 bit DAC */
 305                 green = CNVT_TOHW(green, 8);
 306                 blue = CNVT_TOHW(blue, 8);
 307                 /* hey, there is bug in transp handling... */
 308                 transp = CNVT_TOHW(transp, 8);
 309                 break;
 310         }
 311 #undef CNVT_TOHW
 312         /* Truecolor has hardware independent palette */
 313         if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
 314                 u32 v;
 315
 316                 if (regno >= 16)
 317                         return 1;
 318
 319                 v = (red << info->var.red.offset) |
 320                     (green << info->var.green.offset) |
 321                     (blue << info->var.blue.offset) |
 322                     (transp << info->var.transp.offset);
 323                 switch (info->var.bits_per_pixel) {
 324                 case 8:
 325                         break;
 326                 case 16:
 327                         ((u32 *) (info->pseudo_palette))[regno] = v;
 328                         break;
 329                 case 24:
 330                 case 32:
 331                         ((u32 *) (info->pseudo_palette))[regno] = v;
 332                         break;
 333                 }
 334                 return 0;
 335         }
 336         return 0;
 337 }
 338
 339     /*
 340      *  Pan or Wrap the Display
 341      *
 342      *  This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag
 343      */
 344
 345 static int vfb_pan_display(struct fb_var_screeninfo *var,
 346                            struct fb_info *info)
 347 {
 348         if (var->vmode & FB_VMODE_YWRAP) {
 349                 if (var->yoffset < 0
 350                     || var->yoffset >= info->var.yres_virtual
 351                     || var->xoffset)
 352                         return -EINVAL;
 353         } else {
 354                 if (var->xoffset + var->xres > info->var.xres_virtual ||
 355                     var->yoffset + var->yres > info->var.yres_virtual)
 356                         return -EINVAL;
 357         }
 358         info->var.xoffset = var->xoffset;
 359         info->var.yoffset = var->yoffset;
 360         if (var->vmode & FB_VMODE_YWRAP)
 361                 info->var.vmode |= FB_VMODE_YWRAP;
 362         else
 363                 info->var.vmode &= ~FB_VMODE_YWRAP;
 364         return 0;
 365 }
 366
 367     /*
 368      *  Most drivers don't need their own mmap function
 369      */
 370
 371 static int vfb_mmap(struct fb_info *info,
 372                     struct vm_area_struct *vma)
 373 {
 374         return -EINVAL;
 375 }
 376
 377 #ifndef MODULE
 378 static int __init vfb_setup(char *options)
 379 {
 380         char *this_opt;
 381
 382         vfb_enable = 1;
 383
 384         if (!options || !*options)
 385                 return 1;
 386
 387         while ((this_opt = strsep(&options, ",")) != NULL) {
 388                 if (!*this_opt)
 389                         continue;
 390                 if (!strncmp(this_opt, "disable", 7))
 391                         vfb_enable = 0;
 392         }
 393         return 1;
 394 }
 395 #endif  /*  MODULE  */
 396
 397     /*
 398      *  Initialisation
 399      */
 400
 401 static void vfb_platform_release(struct device *device)
 402 {
 403         // This is called when the reference count goes to zero.
 404 }
 405
 406 static int __init vfb_probe(struct platform_device *dev)
 407 {
 408         struct fb_info *info;
 409         int retval = -ENOMEM;
 410
 411         /*
 412          * For real video cards we use ioremap.
 413          */
 414         if (!(videomemory = vmalloc(videomemorysize)))
 415                 return retval;
 416
 417         /*
 418          * VFB must clear memory to prevent kernel info
 419          * leakage into userspace
 420          * VGA-based drivers MUST NOT clear memory if
 421          * they want to be able to take over vgacon
 422          */
 423         memset(videomemory, 0, videomemorysize);
 424
 425         info = framebuffer_alloc(sizeof(u32) * 256, &dev->dev);
 426         if (!info)
 427                 goto err;
 428
 429         info->screen_base = (char __iomem *)videomemory;
 430         info->fbops = &vfb_ops;
 431
 432         retval = fb_find_mode(&info->var, info, NULL,
 433                               NULL, 0, NULL, 8);
 434
 435         if (!retval || (retval == 4))
 436                 info->var = vfb_default;
 437         info->fix = vfb_fix;
 438         info->pseudo_palette = info->par;
 439         info->par = NULL;
 440         info->flags = FBINFO_FLAG_DEFAULT;
 441
 442         retval = fb_alloc_cmap(&info->cmap, 256, 0);
 443         if (retval < 0)
 444                 goto err1;
 445
 446         retval = register_framebuffer(info);
 447         if (retval < 0)
 448                 goto err2;
 449         platform_set_drvdata(dev, info);
 450
 451         printk(KERN_INFO
 452                "fb%d: Virtual frame buffer device, using %ldK of video memory\n",
 453                info->node, videomemorysize >> 10);
 454         return 0;
 455 err2:
 456         fb_dealloc_cmap(&info->cmap);
 457 err1:
 458         framebuffer_release(info);
 459 err:
 460         vfree(videomemory);
 461         return retval;
 462 }
 463
 464 static int vfb_remove(struct platform_device *dev)
 465 {
 466         struct fb_info *info = platform_get_drvdata(dev);
 467
 468         if (info) {
 469                 unregister_framebuffer(info);
 470                 vfree(videomemory);
 471                 framebuffer_release(info);
 472         }
 473         return 0;
 474 }
 475
 476 static struct platform_driver vfb_driver = {
 477         .probe  = vfb_probe,
 478         .remove = vfb_remove,
 479         .driver = {
 480                 .name   = "vfb",
 481         },
 482 };
 483
 484 static struct platform_device vfb_device = {
 485         .name   = "vfb",
 486         .id     = 0,
 487         .dev    = {
 488                 .release = vfb_platform_release,
 489         }
 490 };
 491
 492 static int __init vfb_init(void)
 493 {
 494         int ret = 0;
 495
 496 #ifndef MODULE
 497         char *option = NULL;
 498
 499         if (fb_get_options("vfb", &option))
 500                 return -ENODEV;
 501         vfb_setup(option);
 502 #endif
 503
 504         if (!vfb_enable)
 505                 return -ENXIO;
 506
 507         ret = platform_driver_register(&vfb_driver);
 508
 509         if (!ret) {
 510                 ret = platform_device_register(&vfb_device);
 511                 if (ret)
 512                         platform_driver_unregister(&vfb_driver);
 513         }
 514         return ret;
 515 }
 516
 517 module_init(vfb_init);
 518
 519 #ifdef MODULE
 520 static void __exit vfb_exit(void)
 521 {
 522         platform_device_unregister(&vfb_device);
 523         platform_driver_unregister(&vfb_driver);
 524 }
 525
 526 module_exit(vfb_exit);
 527
 528 MODULE_LICENSE("GPL");
 529 #endif                          /* MODULE */