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