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