drivers/video/fbdev/udlfb.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * udlfb.c -- Framebuffer driver for DisplayLink USB controller
   4  *
   5  * Copyright (C) 2009 Roberto De Ioris <roberto@unbit.it>
   6  * Copyright (C) 2009 Jaya Kumar <jayakumar.lkml@gmail.com>
   7  * Copyright (C) 2009 Bernie Thompson <bernie@plugable.com>
   8  *
   9  * Layout is based on skeletonfb by James Simmons and Geert Uytterhoeven,
  10  * usb-skeleton by GregKH.
  11  *
  12  * Device-specific portions based on information from Displaylink, with work
  13  * from Florian Echtler, Henrik Bjerregaard Pedersen, and others.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/kernel.h>
  18 #include <linux/init.h>
  19 #include <linux/usb.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/mm.h>
  22 #include <linux/fb.h>
  23 #include <linux/vmalloc.h>
  24 #include <linux/slab.h>
  25 #include <linux/delay.h>
  26 #include <asm/unaligned.h>
  27 #include <video/udlfb.h>
  28 #include "edid.h"
  29
  30 static const struct fb_fix_screeninfo dlfb_fix = {
  31         .id =           "udlfb",
  32         .type =         FB_TYPE_PACKED_PIXELS,
  33         .visual =       FB_VISUAL_TRUECOLOR,
  34         .xpanstep =     0,
  35         .ypanstep =     0,
  36         .ywrapstep =    0,
  37         .accel =        FB_ACCEL_NONE,
  38 };
  39
  40 static const u32 udlfb_info_flags = FBINFO_DEFAULT | FBINFO_READS_FAST |
  41                 FBINFO_VIRTFB |
  42                 FBINFO_HWACCEL_IMAGEBLIT | FBINFO_HWACCEL_FILLRECT |
  43                 FBINFO_HWACCEL_COPYAREA | FBINFO_MISC_ALWAYS_SETPAR;
  44
  45 /*
  46  * There are many DisplayLink-based graphics products, all with unique PIDs.
  47  * So we match on DisplayLink's VID + Vendor-Defined Interface Class (0xff)
  48  * We also require a match on SubClass (0x00) and Protocol (0x00),
  49  * which is compatible with all known USB 2.0 era graphics chips and firmware,
  50  * but allows DisplayLink to increment those for any future incompatible chips
  51  */
  52 static const struct usb_device_id id_table[] = {
  53         {.idVendor = 0x17e9,
  54          .bInterfaceClass = 0xff,
  55          .bInterfaceSubClass = 0x00,
  56          .bInterfaceProtocol = 0x00,
  57          .match_flags = USB_DEVICE_ID_MATCH_VENDOR |
  58                 USB_DEVICE_ID_MATCH_INT_CLASS |
  59                 USB_DEVICE_ID_MATCH_INT_SUBCLASS |
  60                 USB_DEVICE_ID_MATCH_INT_PROTOCOL,
  61         },
  62         {},
  63 };
  64 MODULE_DEVICE_TABLE(usb, id_table);
  65
  66 /* module options */
  67 static bool console = true; /* Allow fbcon to open framebuffer */
  68 static bool fb_defio = true;  /* Detect mmap writes using page faults */
  69 static bool shadow = true; /* Optionally disable shadow framebuffer */
  70 static int pixel_limit; /* Optionally force a pixel resolution limit */
  71
  72 struct dlfb_deferred_free {
  73         struct list_head list;
  74         void *mem;
  75 };
  76
  77 static int dlfb_realloc_framebuffer(struct dlfb_data *dlfb, struct fb_info *info, u32 new_len);
  78
  79 /* dlfb keeps a list of urbs for efficient bulk transfers */
  80 static void dlfb_urb_completion(struct urb *urb);
  81 static struct urb *dlfb_get_urb(struct dlfb_data *dlfb);
  82 static int dlfb_submit_urb(struct dlfb_data *dlfb, struct urb * urb, size_t len);
  83 static int dlfb_alloc_urb_list(struct dlfb_data *dlfb, int count, size_t size);
  84 static void dlfb_free_urb_list(struct dlfb_data *dlfb);
  85
  86 /*
  87  * All DisplayLink bulk operations start with 0xAF, followed by specific code
  88  * All operations are written to buffers which then later get sent to device
  89  */
  90 static char *dlfb_set_register(char *buf, u8 reg, u8 val)
  91 {
  92         *buf++ = 0xAF;
  93         *buf++ = 0x20;
  94         *buf++ = reg;
  95         *buf++ = val;
  96         return buf;
  97 }
  98
  99 static char *dlfb_vidreg_lock(char *buf)
 100 {
 101         return dlfb_set_register(buf, 0xFF, 0x00);
 102 }
 103
 104 static char *dlfb_vidreg_unlock(char *buf)
 105 {
 106         return dlfb_set_register(buf, 0xFF, 0xFF);
 107 }
 108
 109 /*
 110  * Map FB_BLANK_* to DisplayLink register
 111  * DLReg FB_BLANK_*
 112  * ----- -----------------------------
 113  *  0x00 FB_BLANK_UNBLANK (0)
 114  *  0x01 FB_BLANK (1)
 115  *  0x03 FB_BLANK_VSYNC_SUSPEND (2)
 116  *  0x05 FB_BLANK_HSYNC_SUSPEND (3)
 117  *  0x07 FB_BLANK_POWERDOWN (4) Note: requires modeset to come back
 118  */
 119 static char *dlfb_blanking(char *buf, int fb_blank)
 120 {
 121         u8 reg;
 122
 123         switch (fb_blank) {
 124         case FB_BLANK_POWERDOWN:
 125                 reg = 0x07;
 126                 break;
 127         case FB_BLANK_HSYNC_SUSPEND:
 128                 reg = 0x05;
 129                 break;
 130         case FB_BLANK_VSYNC_SUSPEND:
 131                 reg = 0x03;
 132                 break;
 133         case FB_BLANK_NORMAL:
 134                 reg = 0x01;
 135                 break;
 136         default:
 137                 reg = 0x00;
 138         }
 139
 140         buf = dlfb_set_register(buf, 0x1F, reg);
 141
 142         return buf;
 143 }
 144
 145 static char *dlfb_set_color_depth(char *buf, u8 selection)
 146 {
 147         return dlfb_set_register(buf, 0x00, selection);
 148 }
 149
 150 static char *dlfb_set_base16bpp(char *wrptr, u32 base)
 151 {
 152         /* the base pointer is 16 bits wide, 0x20 is hi byte. */
 153         wrptr = dlfb_set_register(wrptr, 0x20, base >> 16);
 154         wrptr = dlfb_set_register(wrptr, 0x21, base >> 8);
 155         return dlfb_set_register(wrptr, 0x22, base);
 156 }
 157
 158 /*
 159  * DisplayLink HW has separate 16bpp and 8bpp framebuffers.
 160  * In 24bpp modes, the low 323 RGB bits go in the 8bpp framebuffer
 161  */
 162 static char *dlfb_set_base8bpp(char *wrptr, u32 base)
 163 {
 164         wrptr = dlfb_set_register(wrptr, 0x26, base >> 16);
 165         wrptr = dlfb_set_register(wrptr, 0x27, base >> 8);
 166         return dlfb_set_register(wrptr, 0x28, base);
 167 }
 168
 169 static char *dlfb_set_register_16(char *wrptr, u8 reg, u16 value)
 170 {
 171         wrptr = dlfb_set_register(wrptr, reg, value >> 8);
 172         return dlfb_set_register(wrptr, reg+1, value);
 173 }
 174
 175 /*
 176  * This is kind of weird because the controller takes some
 177  * register values in a different byte order than other registers.
 178  */
 179 static char *dlfb_set_register_16be(char *wrptr, u8 reg, u16 value)
 180 {
 181         wrptr = dlfb_set_register(wrptr, reg, value);
 182         return dlfb_set_register(wrptr, reg+1, value >> 8);
 183 }
 184
 185 /*
 186  * LFSR is linear feedback shift register. The reason we have this is
 187  * because the display controller needs to minimize the clock depth of
 188  * various counters used in the display path. So this code reverses the
 189  * provided value into the lfsr16 value by counting backwards to get
 190  * the value that needs to be set in the hardware comparator to get the
 191  * same actual count. This makes sense once you read above a couple of
 192  * times and think about it from a hardware perspective.
 193  */
 194 static u16 dlfb_lfsr16(u16 actual_count)
 195 {
 196         u32 lv = 0xFFFF; /* This is the lfsr value that the hw starts with */
 197
 198         while (actual_count--) {
 199                 lv =     ((lv << 1) |
 200                         (((lv >> 15) ^ (lv >> 4) ^ (lv >> 2) ^ (lv >> 1)) & 1))
 201                         & 0xFFFF;
 202         }
 203
 204         return (u16) lv;
 205 }
 206
 207 /*
 208  * This does LFSR conversion on the value that is to be written.
 209  * See LFSR explanation above for more detail.
 210  */
 211 static char *dlfb_set_register_lfsr16(char *wrptr, u8 reg, u16 value)
 212 {
 213         return dlfb_set_register_16(wrptr, reg, dlfb_lfsr16(value));
 214 }
 215
 216 /*
 217  * This takes a standard fbdev screeninfo struct and all of its monitor mode
 218  * details and converts them into the DisplayLink equivalent register commands.
 219  */
 220 static char *dlfb_set_vid_cmds(char *wrptr, struct fb_var_screeninfo *var)
 221 {
 222         u16 xds, yds;
 223         u16 xde, yde;
 224         u16 yec;
 225
 226         /* x display start */
 227         xds = var->left_margin + var->hsync_len;
 228         wrptr = dlfb_set_register_lfsr16(wrptr, 0x01, xds);
 229         /* x display end */
 230         xde = xds + var->xres;
 231         wrptr = dlfb_set_register_lfsr16(wrptr, 0x03, xde);
 232
 233         /* y display start */
 234         yds = var->upper_margin + var->vsync_len;
 235         wrptr = dlfb_set_register_lfsr16(wrptr, 0x05, yds);
 236         /* y display end */
 237         yde = yds + var->yres;
 238         wrptr = dlfb_set_register_lfsr16(wrptr, 0x07, yde);
 239
 240         /* x end count is active + blanking - 1 */
 241         wrptr = dlfb_set_register_lfsr16(wrptr, 0x09,
 242                         xde + var->right_margin - 1);
 243
 244         /* libdlo hardcodes hsync start to 1 */
 245         wrptr = dlfb_set_register_lfsr16(wrptr, 0x0B, 1);
 246
 247         /* hsync end is width of sync pulse + 1 */
 248         wrptr = dlfb_set_register_lfsr16(wrptr, 0x0D, var->hsync_len + 1);
 249
 250         /* hpixels is active pixels */
 251         wrptr = dlfb_set_register_16(wrptr, 0x0F, var->xres);
 252
 253         /* yendcount is vertical active + vertical blanking */
 254         yec = var->yres + var->upper_margin + var->lower_margin +
 255                         var->vsync_len;
 256         wrptr = dlfb_set_register_lfsr16(wrptr, 0x11, yec);
 257
 258         /* libdlo hardcodes vsync start to 0 */
 259         wrptr = dlfb_set_register_lfsr16(wrptr, 0x13, 0);
 260
 261         /* vsync end is width of vsync pulse */
 262         wrptr = dlfb_set_register_lfsr16(wrptr, 0x15, var->vsync_len);
 263
 264         /* vpixels is active pixels */
 265         wrptr = dlfb_set_register_16(wrptr, 0x17, var->yres);
 266
 267         /* convert picoseconds to 5kHz multiple for pclk5k = x * 1E12/5k */
 268         wrptr = dlfb_set_register_16be(wrptr, 0x1B,
 269                         200*1000*1000/var->pixclock);
 270
 271         return wrptr;
 272 }
 273
 274 /*
 275  * This takes a standard fbdev screeninfo struct that was fetched or prepared
 276  * and then generates the appropriate command sequence that then drives the
 277  * display controller.
 278  */
 279 static int dlfb_set_video_mode(struct dlfb_data *dlfb,
 280                                 struct fb_var_screeninfo *var)
 281 {
 282         char *buf;
 283         char *wrptr;
 284         int retval;
 285         int writesize;
 286         struct urb *urb;
 287
 288         if (!atomic_read(&dlfb->usb_active))
 289                 return -EPERM;
 290
 291         urb = dlfb_get_urb(dlfb);
 292         if (!urb)
 293                 return -ENOMEM;
 294
 295         buf = (char *) urb->transfer_buffer;
 296
 297         /*
 298         * This first section has to do with setting the base address on the
 299         * controller * associated with the display. There are 2 base
 300         * pointers, currently, we only * use the 16 bpp segment.
 301         */
 302         wrptr = dlfb_vidreg_lock(buf);
 303         wrptr = dlfb_set_color_depth(wrptr, 0x00);
 304         /* set base for 16bpp segment to 0 */
 305         wrptr = dlfb_set_base16bpp(wrptr, 0);
 306         /* set base for 8bpp segment to end of fb */
 307         wrptr = dlfb_set_base8bpp(wrptr, dlfb->info->fix.smem_len);
 308
 309         wrptr = dlfb_set_vid_cmds(wrptr, var);
 310         wrptr = dlfb_blanking(wrptr, FB_BLANK_UNBLANK);
 311         wrptr = dlfb_vidreg_unlock(wrptr);
 312
 313         writesize = wrptr - buf;
 314
 315         retval = dlfb_submit_urb(dlfb, urb, writesize);
 316
 317         dlfb->blank_mode = FB_BLANK_UNBLANK;
 318
 319         return retval;
 320 }
 321
 322 static int dlfb_ops_mmap(struct fb_info *info, struct vm_area_struct *vma)
 323 {
 324         unsigned long start = vma->vm_start;
 325         unsigned long size = vma->vm_end - vma->vm_start;
 326         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
 327         unsigned long page, pos;
 328
 329         if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
 330                 return -EINVAL;
 331         if (size > info->fix.smem_len)
 332                 return -EINVAL;
 333         if (offset > info->fix.smem_len - size)
 334                 return -EINVAL;
 335
 336         pos = (unsigned long)info->fix.smem_start + offset;
 337
 338         dev_dbg(info->dev, "mmap() framebuffer addr:%lu size:%lu\n",
 339                 pos, size);
 340
 341         while (size > 0) {
 342                 page = vmalloc_to_pfn((void *)pos);
 343                 if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
 344                         return -EAGAIN;
 345
 346                 start += PAGE_SIZE;
 347                 pos += PAGE_SIZE;
 348                 if (size > PAGE_SIZE)
 349                         size -= PAGE_SIZE;
 350                 else
 351                         size = 0;
 352         }
 353
 354         return 0;
 355 }
 356
 357 /*
 358  * Trims identical data from front and back of line
 359  * Sets new front buffer address and width
 360  * And returns byte count of identical pixels
 361  * Assumes CPU natural alignment (unsigned long)
 362  * for back and front buffer ptrs and width
 363  */
 364 static int dlfb_trim_hline(const u8 *bback, const u8 **bfront, int *width_bytes)
 365 {
 366         int j, k;
 367         const unsigned long *back = (const unsigned long *) bback;
 368         const unsigned long *front = (const unsigned long *) *bfront;
 369         const int width = *width_bytes / sizeof(unsigned long);
 370         int identical = width;
 371         int start = width;
 372         int end = width;
 373
 374         for (j = 0; j < width; j++) {
 375                 if (back[j] != front[j]) {
 376                         start = j;
 377                         break;
 378                 }
 379         }
 380
 381         for (k = width - 1; k > j; k--) {
 382                 if (back[k] != front[k]) {
 383                         end = k+1;
 384                         break;
 385                 }
 386         }
 387
 388         identical = start + (width - end);
 389         *bfront = (u8 *) &front[start];
 390         *width_bytes = (end - start) * sizeof(unsigned long);
 391
 392         return identical * sizeof(unsigned long);
 393 }
 394
 395 /*
 396  * Render a command stream for an encoded horizontal line segment of pixels.
 397  *
 398  * A command buffer holds several commands.
 399  * It always begins with a fresh command header
 400  * (the protocol doesn't require this, but we enforce it to allow
 401  * multiple buffers to be potentially encoded and sent in parallel).
 402  * A single command encodes one contiguous horizontal line of pixels
 403  *
 404  * The function relies on the client to do all allocation, so that
 405  * rendering can be done directly to output buffers (e.g. USB URBs).
 406  * The function fills the supplied command buffer, providing information
 407  * on where it left off, so the client may call in again with additional
 408  * buffers if the line will take several buffers to complete.
 409  *
 410  * A single command can transmit a maximum of 256 pixels,
 411  * regardless of the compression ratio (protocol design limit).
 412  * To the hardware, 0 for a size byte means 256
 413  *
 414  * Rather than 256 pixel commands which are either rl or raw encoded,
 415  * the rlx command simply assumes alternating raw and rl spans within one cmd.
 416  * This has a slightly larger header overhead, but produces more even results.
 417  * It also processes all data (read and write) in a single pass.
 418  * Performance benchmarks of common cases show it having just slightly better
 419  * compression than 256 pixel raw or rle commands, with similar CPU consumpion.
 420  * But for very rl friendly data, will compress not quite as well.
 421  */
 422 static void dlfb_compress_hline(
 423         const uint16_t **pixel_start_ptr,
 424         const uint16_t *const pixel_end,
 425         uint32_t *device_address_ptr,
 426         uint8_t **command_buffer_ptr,
 427         const uint8_t *const cmd_buffer_end,
 428         unsigned long back_buffer_offset,
 429         int *ident_ptr)
 430 {
 431         const uint16_t *pixel = *pixel_start_ptr;
 432         uint32_t dev_addr  = *device_address_ptr;
 433         uint8_t *cmd = *command_buffer_ptr;
 434
 435         while ((pixel_end > pixel) &&
 436                (cmd_buffer_end - MIN_RLX_CMD_BYTES > cmd)) {
 437                 uint8_t *raw_pixels_count_byte = NULL;
 438                 uint8_t *cmd_pixels_count_byte = NULL;
 439                 const uint16_t *raw_pixel_start = NULL;
 440                 const uint16_t *cmd_pixel_start, *cmd_pixel_end = NULL;
 441
 442                 if (back_buffer_offset &&
 443                     *pixel == *(u16 *)((u8 *)pixel + back_buffer_offset)) {
 444                         pixel++;
 445                         dev_addr += BPP;
 446                         (*ident_ptr)++;
 447                         continue;
 448                 }
 449
 450                 *cmd++ = 0xAF;
 451                 *cmd++ = 0x6B;
 452                 *cmd++ = dev_addr >> 16;
 453                 *cmd++ = dev_addr >> 8;
 454                 *cmd++ = dev_addr;
 455
 456                 cmd_pixels_count_byte = cmd++; /*  we'll know this later */
 457                 cmd_pixel_start = pixel;
 458
 459                 raw_pixels_count_byte = cmd++; /*  we'll know this later */
 460                 raw_pixel_start = pixel;
 461
 462                 cmd_pixel_end = pixel + min3(MAX_CMD_PIXELS + 1UL,
 463                                         (unsigned long)(pixel_end - pixel),
 464                                         (unsigned long)(cmd_buffer_end - 1 - cmd) / BPP);
 465
 466                 if (back_buffer_offset) {
 467                         /* note: the framebuffer may change under us, so we must test for underflow */
 468                         while (cmd_pixel_end - 1 > pixel &&
 469                                *(cmd_pixel_end - 1) == *(u16 *)((u8 *)(cmd_pixel_end - 1) + back_buffer_offset))
 470                                 cmd_pixel_end--;
 471                 }
 472
 473                 while (pixel < cmd_pixel_end) {
 474                         const uint16_t * const repeating_pixel = pixel;
 475                         u16 pixel_value = *pixel;
 476
 477                         put_unaligned_be16(pixel_value, cmd);
 478                         if (back_buffer_offset)
 479                                 *(u16 *)((u8 *)pixel + back_buffer_offset) = pixel_value;
 480                         cmd += 2;
 481                         pixel++;
 482
 483                         if (unlikely((pixel < cmd_pixel_end) &&
 484                                      (*pixel == pixel_value))) {
 485                                 /* go back and fill in raw pixel count */
 486                                 *raw_pixels_count_byte = ((repeating_pixel -
 487                                                 raw_pixel_start) + 1) & 0xFF;
 488
 489                                 do {
 490                                         if (back_buffer_offset)
 491                                                 *(u16 *)((u8 *)pixel + back_buffer_offset) = pixel_value;
 492                                         pixel++;
 493                                 } while ((pixel < cmd_pixel_end) &&
 494                                          (*pixel == pixel_value));
 495
 496                                 /* immediately after raw data is repeat byte */
 497                                 *cmd++ = ((pixel - repeating_pixel) - 1) & 0xFF;
 498
 499                                 /* Then start another raw pixel span */
 500                                 raw_pixel_start = pixel;
 501                                 raw_pixels_count_byte = cmd++;
 502                         }
 503                 }
 504
 505                 if (pixel > raw_pixel_start) {
 506                         /* finalize last RAW span */
 507                         *raw_pixels_count_byte = (pixel-raw_pixel_start) & 0xFF;
 508                 } else {
 509                         /* undo unused byte */
 510                         cmd--;
 511                 }
 512
 513                 *cmd_pixels_count_byte = (pixel - cmd_pixel_start) & 0xFF;
 514                 dev_addr += (u8 *)pixel - (u8 *)cmd_pixel_start;
 515         }
 516
 517         if (cmd_buffer_end - MIN_RLX_CMD_BYTES <= cmd) {
 518                 /* Fill leftover bytes with no-ops */
 519                 if (cmd_buffer_end > cmd)
 520                         memset(cmd, 0xAF, cmd_buffer_end - cmd);
 521                 cmd = (uint8_t *) cmd_buffer_end;
 522         }
 523
 524         *command_buffer_ptr = cmd;
 525         *pixel_start_ptr = pixel;
 526         *device_address_ptr = dev_addr;
 527 }
 528
 529 /*
 530  * There are 3 copies of every pixel: The front buffer that the fbdev
 531  * client renders to, the actual framebuffer across the USB bus in hardware
 532  * (that we can only write to, slowly, and can never read), and (optionally)
 533  * our shadow copy that tracks what's been sent to that hardware buffer.
 534  */
 535 static int dlfb_render_hline(struct dlfb_data *dlfb, struct urb **urb_ptr,
 536                               const char *front, char **urb_buf_ptr,
 537                               u32 byte_offset, u32 byte_width,
 538                               int *ident_ptr, int *sent_ptr)
 539 {
 540         const u8 *line_start, *line_end, *next_pixel;
 541         u32 dev_addr = dlfb->base16 + byte_offset;
 542         struct urb *urb = *urb_ptr;
 543         u8 *cmd = *urb_buf_ptr;
 544         u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
 545         unsigned long back_buffer_offset = 0;
 546
 547         line_start = (u8 *) (front + byte_offset);
 548         next_pixel = line_start;
 549         line_end = next_pixel + byte_width;
 550
 551         if (dlfb->backing_buffer) {
 552                 int offset;
 553                 const u8 *back_start = (u8 *) (dlfb->backing_buffer
 554                                                 + byte_offset);
 555
 556                 back_buffer_offset = (unsigned long)back_start - (unsigned long)line_start;
 557
 558                 *ident_ptr += dlfb_trim_hline(back_start, &next_pixel,
 559                         &byte_width);
 560
 561                 offset = next_pixel - line_start;
 562                 line_end = next_pixel + byte_width;
 563                 dev_addr += offset;
 564                 back_start += offset;
 565                 line_start += offset;
 566         }
 567
 568         while (next_pixel < line_end) {
 569
 570                 dlfb_compress_hline((const uint16_t **) &next_pixel,
 571                              (const uint16_t *) line_end, &dev_addr,
 572                         (u8 **) &cmd, (u8 *) cmd_end, back_buffer_offset,
 573                         ident_ptr);
 574
 575                 if (cmd >= cmd_end) {
 576                         int len = cmd - (u8 *) urb->transfer_buffer;
 577                         if (dlfb_submit_urb(dlfb, urb, len))
 578                                 return 1; /* lost pixels is set */
 579                         *sent_ptr += len;
 580                         urb = dlfb_get_urb(dlfb);
 581                         if (!urb)
 582                                 return 1; /* lost_pixels is set */
 583                         *urb_ptr = urb;
 584                         cmd = urb->transfer_buffer;
 585                         cmd_end = &cmd[urb->transfer_buffer_length];
 586                 }
 587         }
 588
 589         *urb_buf_ptr = cmd;
 590
 591         return 0;
 592 }
 593
 594 static int dlfb_handle_damage(struct dlfb_data *dlfb, int x, int y, int width, int height)
 595 {
 596         int i, ret;
 597         char *cmd;
 598         cycles_t start_cycles, end_cycles;
 599         int bytes_sent = 0;
 600         int bytes_identical = 0;
 601         struct urb *urb;
 602         int aligned_x;
 603
 604         start_cycles = get_cycles();
 605
 606         mutex_lock(&dlfb->render_mutex);
 607
 608         aligned_x = DL_ALIGN_DOWN(x, sizeof(unsigned long));
 609         width = DL_ALIGN_UP(width + (x-aligned_x), sizeof(unsigned long));
 610         x = aligned_x;
 611
 612         if ((width <= 0) ||
 613             (x + width > dlfb->info->var.xres) ||
 614             (y + height > dlfb->info->var.yres)) {
 615                 ret = -EINVAL;
 616                 goto unlock_ret;
 617         }
 618
 619         if (!atomic_read(&dlfb->usb_active)) {
 620                 ret = 0;
 621                 goto unlock_ret;
 622         }
 623
 624         urb = dlfb_get_urb(dlfb);
 625         if (!urb) {
 626                 ret = 0;
 627                 goto unlock_ret;
 628         }
 629         cmd = urb->transfer_buffer;
 630
 631         for (i = y; i < y + height ; i++) {
 632                 const int line_offset = dlfb->info->fix.line_length * i;
 633                 const int byte_offset = line_offset + (x * BPP);
 634
 635                 if (dlfb_render_hline(dlfb, &urb,
 636                                       (char *) dlfb->info->fix.smem_start,
 637                                       &cmd, byte_offset, width * BPP,
 638                                       &bytes_identical, &bytes_sent))
 639                         goto error;
 640         }
 641
 642         if (cmd > (char *) urb->transfer_buffer) {
 643                 int len;
 644                 if (cmd < (char *) urb->transfer_buffer + urb->transfer_buffer_length)
 645                         *cmd++ = 0xAF;
 646                 /* Send partial buffer remaining before exiting */
 647                 len = cmd - (char *) urb->transfer_buffer;
 648                 dlfb_submit_urb(dlfb, urb, len);
 649                 bytes_sent += len;
 650         } else
 651                 dlfb_urb_completion(urb);
 652
 653 error:
 654         atomic_add(bytes_sent, &dlfb->bytes_sent);
 655         atomic_add(bytes_identical, &dlfb->bytes_identical);
 656         atomic_add(width*height*2, &dlfb->bytes_rendered);
 657         end_cycles = get_cycles();
 658         atomic_add(((unsigned int) ((end_cycles - start_cycles)
 659                     >> 10)), /* Kcycles */
 660                    &dlfb->cpu_kcycles_used);
 661
 662         ret = 0;
 663
 664 unlock_ret:
 665         mutex_unlock(&dlfb->render_mutex);
 666         return ret;
 667 }
 668
 669 static void dlfb_init_damage(struct dlfb_data *dlfb)
 670 {
 671         dlfb->damage_x = INT_MAX;
 672         dlfb->damage_x2 = 0;
 673         dlfb->damage_y = INT_MAX;
 674         dlfb->damage_y2 = 0;
 675 }
 676
 677 static void dlfb_damage_work(struct work_struct *w)
 678 {
 679         struct dlfb_data *dlfb = container_of(w, struct dlfb_data, damage_work);
 680         int x, x2, y, y2;
 681
 682         spin_lock_irq(&dlfb->damage_lock);
 683         x = dlfb->damage_x;
 684         x2 = dlfb->damage_x2;
 685         y = dlfb->damage_y;
 686         y2 = dlfb->damage_y2;
 687         dlfb_init_damage(dlfb);
 688         spin_unlock_irq(&dlfb->damage_lock);
 689
 690         if (x < x2 && y < y2)
 691                 dlfb_handle_damage(dlfb, x, y, x2 - x, y2 - y);
 692 }
 693
 694 static void dlfb_offload_damage(struct dlfb_data *dlfb, int x, int y, int width, int height)
 695 {
 696         unsigned long flags;
 697         int x2 = x + width;
 698         int y2 = y + height;
 699
 700         if (x >= x2 || y >= y2)
 701                 return;
 702
 703         spin_lock_irqsave(&dlfb->damage_lock, flags);
 704         dlfb->damage_x = min(x, dlfb->damage_x);
 705         dlfb->damage_x2 = max(x2, dlfb->damage_x2);
 706         dlfb->damage_y = min(y, dlfb->damage_y);
 707         dlfb->damage_y2 = max(y2, dlfb->damage_y2);
 708         spin_unlock_irqrestore(&dlfb->damage_lock, flags);
 709
 710         schedule_work(&dlfb->damage_work);
 711 }
 712
 713 /*
 714  * Path triggered by usermode clients who write to filesystem
 715  * e.g. cat filename > /dev/fb1
 716  * Not used by X Windows or text-mode console. But useful for testing.
 717  * Slow because of extra copy and we must assume all pixels dirty.
 718  */
 719 static ssize_t dlfb_ops_write(struct fb_info *info, const char __user *buf,
 720                           size_t count, loff_t *ppos)
 721 {
 722         ssize_t result;
 723         struct dlfb_data *dlfb = info->par;
 724         u32 offset = (u32) *ppos;
 725
 726         result = fb_sys_write(info, buf, count, ppos);
 727
 728         if (result > 0) {
 729                 int start = max((int)(offset / info->fix.line_length), 0);
 730                 int lines = min((u32)((result / info->fix.line_length) + 1),
 731                                 (u32)info->var.yres);
 732
 733                 dlfb_handle_damage(dlfb, 0, start, info->var.xres,
 734                         lines);
 735         }
 736
 737         return result;
 738 }
 739
 740 /* hardware has native COPY command (see libdlo), but not worth it for fbcon */
 741 static void dlfb_ops_copyarea(struct fb_info *info,
 742                                 const struct fb_copyarea *area)
 743 {
 744
 745         struct dlfb_data *dlfb = info->par;
 746
 747         sys_copyarea(info, area);
 748
 749         dlfb_offload_damage(dlfb, area->dx, area->dy,
 750                         area->width, area->height);
 751 }
 752
 753 static void dlfb_ops_imageblit(struct fb_info *info,
 754                                 const struct fb_image *image)
 755 {
 756         struct dlfb_data *dlfb = info->par;
 757
 758         sys_imageblit(info, image);
 759
 760         dlfb_offload_damage(dlfb, image->dx, image->dy,
 761                         image->width, image->height);
 762 }
 763
 764 static void dlfb_ops_fillrect(struct fb_info *info,
 765                           const struct fb_fillrect *rect)
 766 {
 767         struct dlfb_data *dlfb = info->par;
 768
 769         sys_fillrect(info, rect);
 770
 771         dlfb_offload_damage(dlfb, rect->dx, rect->dy, rect->width,
 772                               rect->height);
 773 }
 774
 775 /*
 776  * NOTE: fb_defio.c is holding info->fbdefio.mutex
 777  *   Touching ANY framebuffer memory that triggers a page fault
 778  *   in fb_defio will cause a deadlock, when it also tries to
 779  *   grab the same mutex.
 780  */
 781 static void dlfb_dpy_deferred_io(struct fb_info *info,
 782                                 struct list_head *pagelist)
 783 {
 784         struct page *cur;
 785         struct fb_deferred_io *fbdefio = info->fbdefio;
 786         struct dlfb_data *dlfb = info->par;
 787         struct urb *urb;
 788         char *cmd;
 789         cycles_t start_cycles, end_cycles;
 790         int bytes_sent = 0;
 791         int bytes_identical = 0;
 792         int bytes_rendered = 0;
 793
 794         mutex_lock(&dlfb->render_mutex);
 795
 796         if (!fb_defio)
 797                 goto unlock_ret;
 798
 799         if (!atomic_read(&dlfb->usb_active))
 800                 goto unlock_ret;
 801
 802         start_cycles = get_cycles();
 803
 804         urb = dlfb_get_urb(dlfb);
 805         if (!urb)
 806                 goto unlock_ret;
 807
 808         cmd = urb->transfer_buffer;
 809
 810         /* walk the written page list and render each to device */
 811         list_for_each_entry(cur, &fbdefio->pagelist, lru) {
 812
 813                 if (dlfb_render_hline(dlfb, &urb, (char *) info->fix.smem_start,
 814                                   &cmd, cur->index << PAGE_SHIFT,
 815                                   PAGE_SIZE, &bytes_identical, &bytes_sent))
 816                         goto error;
 817                 bytes_rendered += PAGE_SIZE;
 818         }
 819
 820         if (cmd > (char *) urb->transfer_buffer) {
 821                 int len;
 822                 if (cmd < (char *) urb->transfer_buffer + urb->transfer_buffer_length)
 823                         *cmd++ = 0xAF;
 824                 /* Send partial buffer remaining before exiting */
 825                 len = cmd - (char *) urb->transfer_buffer;
 826                 dlfb_submit_urb(dlfb, urb, len);
 827                 bytes_sent += len;
 828         } else
 829                 dlfb_urb_completion(urb);
 830
 831 error:
 832         atomic_add(bytes_sent, &dlfb->bytes_sent);
 833         atomic_add(bytes_identical, &dlfb->bytes_identical);
 834         atomic_add(bytes_rendered, &dlfb->bytes_rendered);
 835         end_cycles = get_cycles();
 836         atomic_add(((unsigned int) ((end_cycles - start_cycles)
 837                     >> 10)), /* Kcycles */
 838                    &dlfb->cpu_kcycles_used);
 839 unlock_ret:
 840         mutex_unlock(&dlfb->render_mutex);
 841 }
 842
 843 static int dlfb_get_edid(struct dlfb_data *dlfb, char *edid, int len)
 844 {
 845         int i, ret;
 846         char *rbuf;
 847
 848         rbuf = kmalloc(2, GFP_KERNEL);
 849         if (!rbuf)
 850                 return 0;
 851
 852         for (i = 0; i < len; i++) {
 853                 ret = usb_control_msg(dlfb->udev,
 854                                       usb_rcvctrlpipe(dlfb->udev, 0), 0x02,
 855                                       (0x80 | (0x02 << 5)), i << 8, 0xA1,
 856                                       rbuf, 2, USB_CTRL_GET_TIMEOUT);
 857                 if (ret < 2) {
 858                         dev_err(&dlfb->udev->dev,
 859                                 "Read EDID byte %d failed: %d\n", i, ret);
 860                         i--;
 861                         break;
 862                 }
 863                 edid[i] = rbuf[1];
 864         }
 865
 866         kfree(rbuf);
 867
 868         return i;
 869 }
 870
 871 static int dlfb_ops_ioctl(struct fb_info *info, unsigned int cmd,
 872                                 unsigned long arg)
 873 {
 874
 875         struct dlfb_data *dlfb = info->par;
 876
 877         if (!atomic_read(&dlfb->usb_active))
 878                 return 0;
 879
 880         /* TODO: Update X server to get this from sysfs instead */
 881         if (cmd == DLFB_IOCTL_RETURN_EDID) {
 882                 void __user *edid = (void __user *)arg;
 883                 if (copy_to_user(edid, dlfb->edid, dlfb->edid_size))
 884                         return -EFAULT;
 885                 return 0;
 886         }
 887
 888         /* TODO: Help propose a standard fb.h ioctl to report mmap damage */
 889         if (cmd == DLFB_IOCTL_REPORT_DAMAGE) {
 890                 struct dloarea area;
 891
 892                 if (copy_from_user(&area, (void __user *)arg,
 893                                   sizeof(struct dloarea)))
 894                         return -EFAULT;
 895
 896                 /*
 897                  * If we have a damage-aware client, turn fb_defio "off"
 898                  * To avoid perf imact of unnecessary page fault handling.
 899                  * Done by resetting the delay for this fb_info to a very
 900                  * long period. Pages will become writable and stay that way.
 901                  * Reset to normal value when all clients have closed this fb.
 902                  */
 903                 if (info->fbdefio)
 904                         info->fbdefio->delay = DL_DEFIO_WRITE_DISABLE;
 905
 906                 if (area.x < 0)
 907                         area.x = 0;
 908
 909                 if (area.x > info->var.xres)
 910                         area.x = info->var.xres;
 911
 912                 if (area.y < 0)
 913                         area.y = 0;
 914
 915                 if (area.y > info->var.yres)
 916                         area.y = info->var.yres;
 917
 918                 dlfb_handle_damage(dlfb, area.x, area.y, area.w, area.h);
 919         }
 920
 921         return 0;
 922 }
 923
 924 /* taken from vesafb */
 925 static int
 926 dlfb_ops_setcolreg(unsigned regno, unsigned red, unsigned green,
 927                unsigned blue, unsigned transp, struct fb_info *info)
 928 {
 929         int err = 0;
 930
 931         if (regno >= info->cmap.len)
 932                 return 1;
 933
 934         if (regno < 16) {
 935                 if (info->var.red.offset == 10) {
 936                         /* 1:5:5:5 */
 937                         ((u32 *) (info->pseudo_palette))[regno] =
 938                             ((red & 0xf800) >> 1) |
 939                             ((green & 0xf800) >> 6) | ((blue & 0xf800) >> 11);
 940                 } else {
 941                         /* 0:5:6:5 */
 942                         ((u32 *) (info->pseudo_palette))[regno] =
 943                             ((red & 0xf800)) |
 944                             ((green & 0xfc00) >> 5) | ((blue & 0xf800) >> 11);
 945                 }
 946         }
 947
 948         return err;
 949 }
 950
 951 /*
 952  * It's common for several clients to have framebuffer open simultaneously.
 953  * e.g. both fbcon and X. Makes things interesting.
 954  * Assumes caller is holding info->lock (for open and release at least)
 955  */
 956 static int dlfb_ops_open(struct fb_info *info, int user)
 957 {
 958         struct dlfb_data *dlfb = info->par;
 959
 960         /*
 961          * fbcon aggressively connects to first framebuffer it finds,
 962          * preventing other clients (X) from working properly. Usually
 963          * not what the user wants. Fail by default with option to enable.
 964          */
 965         if ((user == 0) && (!console))
 966                 return -EBUSY;
 967
 968         /* If the USB device is gone, we don't accept new opens */
 969         if (dlfb->virtualized)
 970                 return -ENODEV;
 971
 972         dlfb->fb_count++;
 973
 974         if (fb_defio && (info->fbdefio == NULL)) {
 975                 /* enable defio at last moment if not disabled by client */
 976
 977                 struct fb_deferred_io *fbdefio;
 978
 979                 fbdefio = kzalloc(sizeof(struct fb_deferred_io), GFP_KERNEL);
 980
 981                 if (fbdefio) {
 982                         fbdefio->delay = DL_DEFIO_WRITE_DELAY;
 983                         fbdefio->sort_pagelist = true;
 984                         fbdefio->deferred_io = dlfb_dpy_deferred_io;
 985                 }
 986
 987                 info->fbdefio = fbdefio;
 988                 fb_deferred_io_init(info);
 989         }
 990
 991         dev_dbg(info->dev, "open, user=%d fb_info=%p count=%d\n",
 992                 user, info, dlfb->fb_count);
 993
 994         return 0;
 995 }
 996
 997 static void dlfb_ops_destroy(struct fb_info *info)
 998 {
 999         struct dlfb_data *dlfb = info->par;
1000
1001         cancel_work_sync(&dlfb->damage_work);
1002
1003         mutex_destroy(&dlfb->render_mutex);
1004
1005         if (info->cmap.len != 0)
1006                 fb_dealloc_cmap(&info->cmap);
1007         if (info->monspecs.modedb)
1008                 fb_destroy_modedb(info->monspecs.modedb);
1009         vfree(info->screen_base);
1010
1011         fb_destroy_modelist(&info->modelist);
1012
1013         while (!list_empty(&dlfb->deferred_free)) {
1014                 struct dlfb_deferred_free *d = list_entry(dlfb->deferred_free.next, struct dlfb_deferred_free, list);
1015                 list_del(&d->list);
1016                 vfree(d->mem);
1017                 kfree(d);
1018         }
1019         vfree(dlfb->backing_buffer);
1020         kfree(dlfb->edid);
1021         dlfb_free_urb_list(dlfb);
1022         usb_put_dev(dlfb->udev);
1023         kfree(dlfb);
1024
1025         /* Assume info structure is freed after this point */
1026         framebuffer_release(info);
1027 }
1028
1029 /*
1030  * Assumes caller is holding info->lock mutex (for open and release at least)
1031  */
1032 static int dlfb_ops_release(struct fb_info *info, int user)
1033 {
1034         struct dlfb_data *dlfb = info->par;
1035
1036         dlfb->fb_count--;
1037
1038         if ((dlfb->fb_count == 0) && (info->fbdefio)) {
1039                 fb_deferred_io_cleanup(info);
1040                 kfree(info->fbdefio);
1041                 info->fbdefio = NULL;
1042         }
1043
1044         dev_dbg(info->dev, "release, user=%d count=%d\n", user, dlfb->fb_count);
1045
1046         return 0;
1047 }
1048
1049 /*
1050  * Check whether a video mode is supported by the DisplayLink chip
1051  * We start from monitor's modes, so don't need to filter that here
1052  */
1053 static int dlfb_is_valid_mode(struct fb_videomode *mode, struct dlfb_data *dlfb)
1054 {
1055         if (mode->xres * mode->yres > dlfb->sku_pixel_limit)
1056                 return 0;
1057
1058         return 1;
1059 }
1060
1061 static void dlfb_var_color_format(struct fb_var_screeninfo *var)
1062 {
1063         const struct fb_bitfield red = { 11, 5, 0 };
1064         const struct fb_bitfield green = { 5, 6, 0 };
1065         const struct fb_bitfield blue = { 0, 5, 0 };
1066
1067         var->bits_per_pixel = 16;
1068         var->red = red;
1069         var->green = green;
1070         var->blue = blue;
1071 }
1072
1073 static int dlfb_ops_check_var(struct fb_var_screeninfo *var,
1074                                 struct fb_info *info)
1075 {
1076         struct fb_videomode mode;
1077         struct dlfb_data *dlfb = info->par;
1078
1079         /* set device-specific elements of var unrelated to mode */
1080         dlfb_var_color_format(var);
1081
1082         fb_var_to_videomode(&mode, var);
1083
1084         if (!dlfb_is_valid_mode(&mode, dlfb))
1085                 return -EINVAL;
1086
1087         return 0;
1088 }
1089
1090 static int dlfb_ops_set_par(struct fb_info *info)
1091 {
1092         struct dlfb_data *dlfb = info->par;
1093         int result;
1094         u16 *pix_framebuffer;
1095         int i;
1096         struct fb_var_screeninfo fvs;
1097         u32 line_length = info->var.xres * (info->var.bits_per_pixel / 8);
1098
1099         /* clear the activate field because it causes spurious miscompares */
1100         fvs = info->var;
1101         fvs.activate = 0;
1102         fvs.vmode &= ~FB_VMODE_SMOOTH_XPAN;
1103
1104         if (!memcmp(&dlfb->current_mode, &fvs, sizeof(struct fb_var_screeninfo)))
1105                 return 0;
1106
1107         result = dlfb_realloc_framebuffer(dlfb, info, info->var.yres * line_length);
1108         if (result)
1109                 return result;
1110
1111         result = dlfb_set_video_mode(dlfb, &info->var);
1112
1113         if (result)
1114                 return result;
1115
1116         dlfb->current_mode = fvs;
1117         info->fix.line_length = line_length;
1118
1119         if (dlfb->fb_count == 0) {
1120
1121                 /* paint greenscreen */
1122
1123                 pix_framebuffer = (u16 *) info->screen_base;
1124                 for (i = 0; i < info->fix.smem_len / 2; i++)
1125                         pix_framebuffer[i] = 0x37e6;
1126         }
1127
1128         dlfb_handle_damage(dlfb, 0, 0, info->var.xres, info->var.yres);
1129
1130         return 0;
1131 }
1132
1133 /* To fonzi the jukebox (e.g. make blanking changes take effect) */
1134 static char *dlfb_dummy_render(char *buf)
1135 {
1136         *buf++ = 0xAF;
1137         *buf++ = 0x6A; /* copy */
1138         *buf++ = 0x00; /* from address*/
1139         *buf++ = 0x00;
1140         *buf++ = 0x00;
1141         *buf++ = 0x01; /* one pixel */
1142         *buf++ = 0x00; /* to address */
1143         *buf++ = 0x00;
1144         *buf++ = 0x00;
1145         return buf;
1146 }
1147
1148 /*
1149  * In order to come back from full DPMS off, we need to set the mode again
1150  */
1151 static int dlfb_ops_blank(int blank_mode, struct fb_info *info)
1152 {
1153         struct dlfb_data *dlfb = info->par;
1154         char *bufptr;
1155         struct urb *urb;
1156
1157         dev_dbg(info->dev, "blank, mode %d --> %d\n",
1158                 dlfb->blank_mode, blank_mode);
1159
1160         if ((dlfb->blank_mode == FB_BLANK_POWERDOWN) &&
1161             (blank_mode != FB_BLANK_POWERDOWN)) {
1162
1163                 /* returning from powerdown requires a fresh modeset */
1164                 dlfb_set_video_mode(dlfb, &info->var);
1165         }
1166
1167         urb = dlfb_get_urb(dlfb);
1168         if (!urb)
1169                 return 0;
1170
1171         bufptr = (char *) urb->transfer_buffer;
1172         bufptr = dlfb_vidreg_lock(bufptr);
1173         bufptr = dlfb_blanking(bufptr, blank_mode);
1174         bufptr = dlfb_vidreg_unlock(bufptr);
1175
1176         /* seems like a render op is needed to have blank change take effect */
1177         bufptr = dlfb_dummy_render(bufptr);
1178
1179         dlfb_submit_urb(dlfb, urb, bufptr -
1180                         (char *) urb->transfer_buffer);
1181
1182         dlfb->blank_mode = blank_mode;
1183
1184         return 0;
1185 }
1186
1187 static const struct fb_ops dlfb_ops = {
1188         .owner = THIS_MODULE,
1189         .fb_read = fb_sys_read,
1190         .fb_write = dlfb_ops_write,
1191         .fb_setcolreg = dlfb_ops_setcolreg,
1192         .fb_fillrect = dlfb_ops_fillrect,
1193         .fb_copyarea = dlfb_ops_copyarea,
1194         .fb_imageblit = dlfb_ops_imageblit,
1195         .fb_mmap = dlfb_ops_mmap,
1196         .fb_ioctl = dlfb_ops_ioctl,
1197         .fb_open = dlfb_ops_open,
1198         .fb_release = dlfb_ops_release,
1199         .fb_blank = dlfb_ops_blank,
1200         .fb_check_var = dlfb_ops_check_var,
1201         .fb_set_par = dlfb_ops_set_par,
1202         .fb_destroy = dlfb_ops_destroy,
1203 };
1204
1205
1206 static void dlfb_deferred_vfree(struct dlfb_data *dlfb, void *mem)
1207 {
1208         struct dlfb_deferred_free *d = kmalloc(sizeof(struct dlfb_deferred_free), GFP_KERNEL);
1209         if (!d)
1210                 return;
1211         d->mem = mem;
1212         list_add(&d->list, &dlfb->deferred_free);
1213 }
1214
1215 /*
1216  * Assumes &info->lock held by caller
1217  * Assumes no active clients have framebuffer open
1218  */
1219 static int dlfb_realloc_framebuffer(struct dlfb_data *dlfb, struct fb_info *info, u32 new_len)
1220 {
1221         u32 old_len = info->fix.smem_len;
1222         const void *old_fb = (const void __force *)info->screen_base;
1223         unsigned char *new_fb;
1224         unsigned char *new_back = NULL;
1225
1226         new_len = PAGE_ALIGN(new_len);
1227
1228         if (new_len > old_len) {
1229                 /*
1230                  * Alloc system memory for virtual framebuffer
1231                  */
1232                 new_fb = vmalloc(new_len);
1233                 if (!new_fb) {
1234                         dev_err(info->dev, "Virtual framebuffer alloc failed\n");
1235                         return -ENOMEM;
1236                 }
1237                 memset(new_fb, 0xff, new_len);
1238
1239                 if (info->screen_base) {
1240                         memcpy(new_fb, old_fb, old_len);
1241                         dlfb_deferred_vfree(dlfb, (void __force *)info->screen_base);
1242                 }
1243
1244                 info->screen_base = (char __iomem *)new_fb;
1245                 info->fix.smem_len = new_len;
1246                 info->fix.smem_start = (unsigned long) new_fb;
1247                 info->flags = udlfb_info_flags;
1248
1249                 /*
1250                  * Second framebuffer copy to mirror the framebuffer state
1251                  * on the physical USB device. We can function without this.
1252                  * But with imperfect damage info we may send pixels over USB
1253                  * that were, in fact, unchanged - wasting limited USB bandwidth
1254                  */
1255                 if (shadow)
1256                         new_back = vzalloc(new_len);
1257                 if (!new_back)
1258                         dev_info(info->dev,
1259                                  "No shadow/backing buffer allocated\n");
1260                 else {
1261                         dlfb_deferred_vfree(dlfb, dlfb->backing_buffer);
1262                         dlfb->backing_buffer = new_back;
1263                 }
1264         }
1265         return 0;
1266 }
1267
1268 /*
1269  * 1) Get EDID from hw, or use sw default
1270  * 2) Parse into various fb_info structs
1271  * 3) Allocate virtual framebuffer memory to back highest res mode
1272  *
1273  * Parses EDID into three places used by various parts of fbdev:
1274  * fb_var_screeninfo contains the timing of the monitor's preferred mode
1275  * fb_info.monspecs is full parsed EDID info, including monspecs.modedb
1276  * fb_info.modelist is a linked list of all monitor & VESA modes which work
1277  *
1278  * If EDID is not readable/valid, then modelist is all VESA modes,
1279  * monspecs is NULL, and fb_var_screeninfo is set to safe VESA mode
1280  * Returns 0 if successful
1281  */
1282 static int dlfb_setup_modes(struct dlfb_data *dlfb,
1283                            struct fb_info *info,
1284                            char *default_edid, size_t default_edid_size)
1285 {
1286         char *edid;
1287         int i, result = 0, tries = 3;
1288         struct device *dev = info->device;
1289         struct fb_videomode *mode;
1290         const struct fb_videomode *default_vmode = NULL;
1291
1292         if (info->dev) {
1293                 /* only use mutex if info has been registered */
1294                 mutex_lock(&info->lock);
1295                 /* parent device is used otherwise */
1296                 dev = info->dev;
1297         }
1298
1299         edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
1300         if (!edid) {
1301                 result = -ENOMEM;
1302                 goto error;
1303         }
1304
1305         fb_destroy_modelist(&info->modelist);
1306         memset(&info->monspecs, 0, sizeof(info->monspecs));
1307
1308         /*
1309          * Try to (re)read EDID from hardware first
1310          * EDID data may return, but not parse as valid
1311          * Try again a few times, in case of e.g. analog cable noise
1312          */
1313         while (tries--) {
1314
1315                 i = dlfb_get_edid(dlfb, edid, EDID_LENGTH);
1316
1317                 if (i >= EDID_LENGTH)
1318                         fb_edid_to_monspecs(edid, &info->monspecs);
1319
1320                 if (info->monspecs.modedb_len > 0) {
1321                         dlfb->edid = edid;
1322                         dlfb->edid_size = i;
1323                         break;
1324                 }
1325         }
1326
1327         /* If that fails, use a previously returned EDID if available */
1328         if (info->monspecs.modedb_len == 0) {
1329                 dev_err(dev, "Unable to get valid EDID from device/display\n");
1330
1331                 if (dlfb->edid) {
1332                         fb_edid_to_monspecs(dlfb->edid, &info->monspecs);
1333                         if (info->monspecs.modedb_len > 0)
1334                                 dev_err(dev, "Using previously queried EDID\n");
1335                 }
1336         }
1337
1338         /* If that fails, use the default EDID we were handed */
1339         if (info->monspecs.modedb_len == 0) {
1340                 if (default_edid_size >= EDID_LENGTH) {
1341                         fb_edid_to_monspecs(default_edid, &info->monspecs);
1342                         if (info->monspecs.modedb_len > 0) {
1343                                 memcpy(edid, default_edid, default_edid_size);
1344                                 dlfb->edid = edid;
1345                                 dlfb->edid_size = default_edid_size;
1346                                 dev_err(dev, "Using default/backup EDID\n");
1347                         }
1348                 }
1349         }
1350
1351         /* If we've got modes, let's pick a best default mode */
1352         if (info->monspecs.modedb_len > 0) {
1353
1354                 for (i = 0; i < info->monspecs.modedb_len; i++) {
1355                         mode = &info->monspecs.modedb[i];
1356                         if (dlfb_is_valid_mode(mode, dlfb)) {
1357                                 fb_add_videomode(mode, &info->modelist);
1358                         } else {
1359                                 dev_dbg(dev, "Specified mode %dx%d too big\n",
1360                                         mode->xres, mode->yres);
1361                                 if (i == 0)
1362                                         /* if we've removed top/best mode */
1363                                         info->monspecs.misc
1364                                                 &= ~FB_MISC_1ST_DETAIL;
1365                         }
1366                 }
1367
1368                 default_vmode = fb_find_best_display(&info->monspecs,
1369                                                      &info->modelist);
1370         }
1371
1372         /* If everything else has failed, fall back to safe default mode */
1373         if (default_vmode == NULL) {
1374
1375                 struct fb_videomode fb_vmode = {0};
1376
1377                 /*
1378                  * Add the standard VESA modes to our modelist
1379                  * Since we don't have EDID, there may be modes that
1380                  * overspec monitor and/or are incorrect aspect ratio, etc.
1381                  * But at least the user has a chance to choose
1382                  */
1383                 for (i = 0; i < VESA_MODEDB_SIZE; i++) {
1384                         mode = (struct fb_videomode *)&vesa_modes[i];
1385                         if (dlfb_is_valid_mode(mode, dlfb))
1386                                 fb_add_videomode(mode, &info->modelist);
1387                         else
1388                                 dev_dbg(dev, "VESA mode %dx%d too big\n",
1389                                         mode->xres, mode->yres);
1390                 }
1391
1392                 /*
1393                  * default to resolution safe for projectors
1394                  * (since they are most common case without EDID)
1395                  */
1396                 fb_vmode.xres = 800;
1397                 fb_vmode.yres = 600;
1398                 fb_vmode.refresh = 60;
1399                 default_vmode = fb_find_nearest_mode(&fb_vmode,
1400                                                      &info->modelist);
1401         }
1402
1403         /* If we have good mode and no active clients*/
1404         if ((default_vmode != NULL) && (dlfb->fb_count == 0)) {
1405
1406                 fb_videomode_to_var(&info->var, default_vmode);
1407                 dlfb_var_color_format(&info->var);
1408
1409                 /*
1410                  * with mode size info, we can now alloc our framebuffer.
1411                  */
1412                 memcpy(&info->fix, &dlfb_fix, sizeof(dlfb_fix));
1413         } else
1414                 result = -EINVAL;
1415
1416 error:
1417         if (edid && (dlfb->edid != edid))
1418                 kfree(edid);
1419
1420         if (info->dev)
1421                 mutex_unlock(&info->lock);
1422
1423         return result;
1424 }
1425
1426 static ssize_t metrics_bytes_rendered_show(struct device *fbdev,
1427                                    struct device_attribute *a, char *buf) {
1428         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1429         struct dlfb_data *dlfb = fb_info->par;
1430         return sysfs_emit(buf, "%u\n",
1431                         atomic_read(&dlfb->bytes_rendered));
1432 }
1433
1434 static ssize_t metrics_bytes_identical_show(struct device *fbdev,
1435                                    struct device_attribute *a, char *buf) {
1436         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1437         struct dlfb_data *dlfb = fb_info->par;
1438         return sysfs_emit(buf, "%u\n",
1439                         atomic_read(&dlfb->bytes_identical));
1440 }
1441
1442 static ssize_t metrics_bytes_sent_show(struct device *fbdev,
1443                                    struct device_attribute *a, char *buf) {
1444         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1445         struct dlfb_data *dlfb = fb_info->par;
1446         return sysfs_emit(buf, "%u\n",
1447                         atomic_read(&dlfb->bytes_sent));
1448 }
1449
1450 static ssize_t metrics_cpu_kcycles_used_show(struct device *fbdev,
1451                                    struct device_attribute *a, char *buf) {
1452         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1453         struct dlfb_data *dlfb = fb_info->par;
1454         return sysfs_emit(buf, "%u\n",
1455                         atomic_read(&dlfb->cpu_kcycles_used));
1456 }
1457
1458 static ssize_t edid_show(
1459                         struct file *filp,
1460                         struct kobject *kobj, struct bin_attribute *a,
1461                          char *buf, loff_t off, size_t count) {
1462         struct device *fbdev = kobj_to_dev(kobj);
1463         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1464         struct dlfb_data *dlfb = fb_info->par;
1465
1466         if (dlfb->edid == NULL)
1467                 return 0;
1468
1469         if ((off >= dlfb->edid_size) || (count > dlfb->edid_size))
1470                 return 0;
1471
1472         if (off + count > dlfb->edid_size)
1473                 count = dlfb->edid_size - off;
1474
1475         memcpy(buf, dlfb->edid, count);
1476
1477         return count;
1478 }
1479
1480 static ssize_t edid_store(
1481                         struct file *filp,
1482                         struct kobject *kobj, struct bin_attribute *a,
1483                         char *src, loff_t src_off, size_t src_size) {
1484         struct device *fbdev = kobj_to_dev(kobj);
1485         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1486         struct dlfb_data *dlfb = fb_info->par;
1487         int ret;
1488
1489         /* We only support write of entire EDID at once, no offset*/
1490         if ((src_size != EDID_LENGTH) || (src_off != 0))
1491                 return -EINVAL;
1492
1493         ret = dlfb_setup_modes(dlfb, fb_info, src, src_size);
1494         if (ret)
1495                 return ret;
1496
1497         if (!dlfb->edid || memcmp(src, dlfb->edid, src_size))
1498                 return -EINVAL;
1499
1500         ret = dlfb_ops_set_par(fb_info);
1501         if (ret)
1502                 return ret;
1503
1504         return src_size;
1505 }
1506
1507 static ssize_t metrics_reset_store(struct device *fbdev,
1508                            struct device_attribute *attr,
1509                            const char *buf, size_t count)
1510 {
1511         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1512         struct dlfb_data *dlfb = fb_info->par;
1513
1514         atomic_set(&dlfb->bytes_rendered, 0);
1515         atomic_set(&dlfb->bytes_identical, 0);
1516         atomic_set(&dlfb->bytes_sent, 0);
1517         atomic_set(&dlfb->cpu_kcycles_used, 0);
1518
1519         return count;
1520 }
1521
1522 static const struct bin_attribute edid_attr = {
1523         .attr.name = "edid",
1524         .attr.mode = 0666,
1525         .size = EDID_LENGTH,
1526         .read = edid_show,
1527         .write = edid_store
1528 };
1529
1530 static const struct device_attribute fb_device_attrs[] = {
1531         __ATTR_RO(metrics_bytes_rendered),
1532         __ATTR_RO(metrics_bytes_identical),
1533         __ATTR_RO(metrics_bytes_sent),
1534         __ATTR_RO(metrics_cpu_kcycles_used),
1535         __ATTR(metrics_reset, S_IWUSR, NULL, metrics_reset_store),
1536 };
1537
1538 /*
1539  * This is necessary before we can communicate with the display controller.
1540  */
1541 static int dlfb_select_std_channel(struct dlfb_data *dlfb)
1542 {
1543         int ret;
1544         void *buf;
1545         static const u8 set_def_chn[] = {
1546                                 0x57, 0xCD, 0xDC, 0xA7,
1547                                 0x1C, 0x88, 0x5E, 0x15,
1548                                 0x60, 0xFE, 0xC6, 0x97,
1549                                 0x16, 0x3D, 0x47, 0xF2  };
1550
1551         buf = kmemdup(set_def_chn, sizeof(set_def_chn), GFP_KERNEL);
1552
1553         if (!buf)
1554                 return -ENOMEM;
1555
1556         ret = usb_control_msg(dlfb->udev, usb_sndctrlpipe(dlfb->udev, 0),
1557                         NR_USB_REQUEST_CHANNEL,
1558                         (USB_DIR_OUT | USB_TYPE_VENDOR), 0, 0,
1559                         buf, sizeof(set_def_chn), USB_CTRL_SET_TIMEOUT);
1560
1561         kfree(buf);
1562
1563         return ret;
1564 }
1565
1566 static int dlfb_parse_vendor_descriptor(struct dlfb_data *dlfb,
1567                                         struct usb_interface *intf)
1568 {
1569         char *desc;
1570         char *buf;
1571         char *desc_end;
1572         int total_len;
1573
1574         buf = kzalloc(MAX_VENDOR_DESCRIPTOR_SIZE, GFP_KERNEL);
1575         if (!buf)
1576                 return false;
1577         desc = buf;
1578
1579         total_len = usb_get_descriptor(interface_to_usbdev(intf),
1580                                         0x5f, /* vendor specific */
1581                                         0, desc, MAX_VENDOR_DESCRIPTOR_SIZE);
1582
1583         /* if not found, look in configuration descriptor */
1584         if (total_len < 0) {
1585                 if (0 == usb_get_extra_descriptor(intf->cur_altsetting,
1586                         0x5f, &desc))
1587                         total_len = (int) desc[0];
1588         }
1589
1590         if (total_len > 5) {
1591                 dev_info(&intf->dev,
1592                          "vendor descriptor length: %d data: %11ph\n",
1593                          total_len, desc);
1594
1595                 if ((desc[0] != total_len) || /* descriptor length */
1596                     (desc[1] != 0x5f) ||   /* vendor descriptor type */
1597                     (desc[2] != 0x01) ||   /* version (2 bytes) */
1598                     (desc[3] != 0x00) ||
1599                     (desc[4] != total_len - 2)) /* length after type */
1600                         goto unrecognized;
1601
1602                 desc_end = desc + total_len;
1603                 desc += 5; /* the fixed header we've already parsed */
1604
1605                 while (desc < desc_end) {
1606                         u8 length;
1607                         u16 key;
1608
1609                         key = *desc++;
1610                         key |= (u16)*desc++ << 8;
1611                         length = *desc++;
1612
1613                         switch (key) {
1614                         case 0x0200: { /* max_area */
1615                                 u32 max_area = *desc++;
1616                                 max_area |= (u32)*desc++ << 8;
1617                                 max_area |= (u32)*desc++ << 16;
1618                                 max_area |= (u32)*desc++ << 24;
1619                                 dev_warn(&intf->dev,
1620                                          "DL chip limited to %d pixel modes\n",
1621                                          max_area);
1622                                 dlfb->sku_pixel_limit = max_area;
1623                                 break;
1624                         }
1625                         default:
1626                                 break;
1627                         }
1628                         desc += length;
1629                 }
1630         } else {
1631                 dev_info(&intf->dev, "vendor descriptor not available (%d)\n",
1632                          total_len);
1633         }
1634
1635         goto success;
1636
1637 unrecognized:
1638         /* allow udlfb to load for now even if firmware unrecognized */
1639         dev_err(&intf->dev, "Unrecognized vendor firmware descriptor\n");
1640
1641 success:
1642         kfree(buf);
1643         return true;
1644 }
1645
1646 static int dlfb_usb_probe(struct usb_interface *intf,
1647                           const struct usb_device_id *id)
1648 {
1649         int i;
1650         const struct device_attribute *attr;
1651         struct dlfb_data *dlfb;
1652         struct fb_info *info;
1653         int retval;
1654         struct usb_device *usbdev = interface_to_usbdev(intf);
1655         struct usb_endpoint_descriptor *out;
1656
1657         /* usb initialization */
1658         dlfb = kzalloc(sizeof(*dlfb), GFP_KERNEL);
1659         if (!dlfb) {
1660                 dev_err(&intf->dev, "%s: failed to allocate dlfb\n", __func__);
1661                 return -ENOMEM;
1662         }
1663
1664         INIT_LIST_HEAD(&dlfb->deferred_free);
1665
1666         dlfb->udev = usb_get_dev(usbdev);
1667         usb_set_intfdata(intf, dlfb);
1668
1669         retval = usb_find_common_endpoints(intf->cur_altsetting, NULL, &out, NULL, NULL);
1670         if (retval) {
1671                 dev_err(&intf->dev, "Device should have at lease 1 bulk endpoint!\n");
1672                 goto error;
1673         }
1674
1675         dev_dbg(&intf->dev, "console enable=%d\n", console);
1676         dev_dbg(&intf->dev, "fb_defio enable=%d\n", fb_defio);
1677         dev_dbg(&intf->dev, "shadow enable=%d\n", shadow);
1678
1679         dlfb->sku_pixel_limit = 2048 * 1152; /* default to maximum */
1680
1681         if (!dlfb_parse_vendor_descriptor(dlfb, intf)) {
1682                 dev_err(&intf->dev,
1683                         "firmware not recognized, incompatible device?\n");
1684                 retval = -ENODEV;
1685                 goto error;
1686         }
1687
1688         if (pixel_limit) {
1689                 dev_warn(&intf->dev,
1690                          "DL chip limit of %d overridden to %d\n",
1691                          dlfb->sku_pixel_limit, pixel_limit);
1692                 dlfb->sku_pixel_limit = pixel_limit;
1693         }
1694
1695
1696         /* allocates framebuffer driver structure, not framebuffer memory */
1697         info = framebuffer_alloc(0, &dlfb->udev->dev);
1698         if (!info) {
1699                 retval = -ENOMEM;
1700                 goto error;
1701         }
1702
1703         dlfb->info = info;
1704         info->par = dlfb;
1705         info->pseudo_palette = dlfb->pseudo_palette;
1706         dlfb->ops = dlfb_ops;
1707         info->fbops = &dlfb->ops;
1708
1709         mutex_init(&dlfb->render_mutex);
1710         dlfb_init_damage(dlfb);
1711         spin_lock_init(&dlfb->damage_lock);
1712         INIT_WORK(&dlfb->damage_work, dlfb_damage_work);
1713
1714         INIT_LIST_HEAD(&info->modelist);
1715
1716         if (!dlfb_alloc_urb_list(dlfb, WRITES_IN_FLIGHT, MAX_TRANSFER)) {
1717                 retval = -ENOMEM;
1718                 dev_err(&intf->dev, "unable to allocate urb list\n");
1719                 goto error;
1720         }
1721
1722         /* We don't register a new USB class. Our client interface is dlfbev */
1723
1724         retval = fb_alloc_cmap(&info->cmap, 256, 0);
1725         if (retval < 0) {
1726                 dev_err(info->device, "cmap allocation failed: %d\n", retval);
1727                 goto error;
1728         }
1729
1730         retval = dlfb_setup_modes(dlfb, info, NULL, 0);
1731         if (retval != 0) {
1732                 dev_err(info->device,
1733                         "unable to find common mode for display and adapter\n");
1734                 goto error;
1735         }
1736
1737         /* ready to begin using device */
1738
1739         atomic_set(&dlfb->usb_active, 1);
1740         dlfb_select_std_channel(dlfb);
1741
1742         dlfb_ops_check_var(&info->var, info);
1743         retval = dlfb_ops_set_par(info);
1744         if (retval)
1745                 goto error;
1746
1747         retval = register_framebuffer(info);
1748         if (retval < 0) {
1749                 dev_err(info->device, "unable to register framebuffer: %d\n",
1750                         retval);
1751                 goto error;
1752         }
1753
1754         for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++) {
1755                 attr = &fb_device_attrs[i];
1756                 retval = device_create_file(info->dev, attr);
1757                 if (retval)
1758                         dev_warn(info->device,
1759                                  "failed to create '%s' attribute: %d\n",
1760                                  attr->attr.name, retval);
1761         }
1762
1763         retval = device_create_bin_file(info->dev, &edid_attr);
1764         if (retval)
1765                 dev_warn(info->device, "failed to create '%s' attribute: %d\n",
1766                          edid_attr.attr.name, retval);
1767
1768         dev_info(info->device,
1769                  "%s is DisplayLink USB device (%dx%d, %dK framebuffer memory)\n",
1770                  dev_name(info->dev), info->var.xres, info->var.yres,
1771                  ((dlfb->backing_buffer) ?
1772                  info->fix.smem_len * 2 : info->fix.smem_len) >> 10);
1773         return 0;
1774
1775 error:
1776         if (dlfb->info) {
1777                 dlfb_ops_destroy(dlfb->info);
1778         } else {
1779                 usb_put_dev(dlfb->udev);
1780                 kfree(dlfb);
1781         }
1782         return retval;
1783 }
1784
1785 static void dlfb_usb_disconnect(struct usb_interface *intf)
1786 {
1787         struct dlfb_data *dlfb;
1788         struct fb_info *info;
1789         int i;
1790
1791         dlfb = usb_get_intfdata(intf);
1792         info = dlfb->info;
1793
1794         dev_dbg(&intf->dev, "USB disconnect starting\n");
1795
1796         /* we virtualize until all fb clients release. Then we free */
1797         dlfb->virtualized = true;
1798
1799         /* When non-active we'll update virtual framebuffer, but no new urbs */
1800         atomic_set(&dlfb->usb_active, 0);
1801
1802         /* this function will wait for all in-flight urbs to complete */
1803         dlfb_free_urb_list(dlfb);
1804
1805         /* remove udlfb's sysfs interfaces */
1806         for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
1807                 device_remove_file(info->dev, &fb_device_attrs[i]);
1808         device_remove_bin_file(info->dev, &edid_attr);
1809
1810         unregister_framebuffer(info);
1811 }
1812
1813 static struct usb_driver dlfb_driver = {
1814         .name = "udlfb",
1815         .probe = dlfb_usb_probe,
1816         .disconnect = dlfb_usb_disconnect,
1817         .id_table = id_table,
1818 };
1819
1820 module_usb_driver(dlfb_driver);
1821
1822 static void dlfb_urb_completion(struct urb *urb)
1823 {
1824         struct urb_node *unode = urb->context;
1825         struct dlfb_data *dlfb = unode->dlfb;
1826         unsigned long flags;
1827
1828         switch (urb->status) {
1829         case 0:
1830                 /* success */
1831                 break;
1832         case -ECONNRESET:
1833         case -ENOENT:
1834         case -ESHUTDOWN:
1835                 /* sync/async unlink faults aren't errors */
1836                 break;
1837         default:
1838                 dev_err(&dlfb->udev->dev,
1839                         "%s - nonzero write bulk status received: %d\n",
1840                         __func__, urb->status);
1841                 atomic_set(&dlfb->lost_pixels, 1);
1842                 break;
1843         }
1844
1845         urb->transfer_buffer_length = dlfb->urbs.size; /* reset to actual */
1846
1847         spin_lock_irqsave(&dlfb->urbs.lock, flags);
1848         list_add_tail(&unode->entry, &dlfb->urbs.list);
1849         dlfb->urbs.available++;
1850         spin_unlock_irqrestore(&dlfb->urbs.lock, flags);
1851
1852         up(&dlfb->urbs.limit_sem);
1853 }
1854
1855 static void dlfb_free_urb_list(struct dlfb_data *dlfb)
1856 {
1857         int count = dlfb->urbs.count;
1858         struct list_head *node;
1859         struct urb_node *unode;
1860         struct urb *urb;
1861
1862         /* keep waiting and freeing, until we've got 'em all */
1863         while (count--) {
1864                 down(&dlfb->urbs.limit_sem);
1865
1866                 spin_lock_irq(&dlfb->urbs.lock);
1867
1868                 node = dlfb->urbs.list.next; /* have reserved one with sem */
1869                 list_del_init(node);
1870
1871                 spin_unlock_irq(&dlfb->urbs.lock);
1872
1873                 unode = list_entry(node, struct urb_node, entry);
1874                 urb = unode->urb;
1875
1876                 /* Free each separately allocated piece */
1877                 usb_free_coherent(urb->dev, dlfb->urbs.size,
1878                                   urb->transfer_buffer, urb->transfer_dma);
1879                 usb_free_urb(urb);
1880                 kfree(node);
1881         }
1882
1883         dlfb->urbs.count = 0;
1884 }
1885
1886 static int dlfb_alloc_urb_list(struct dlfb_data *dlfb, int count, size_t size)
1887 {
1888         struct urb *urb;
1889         struct urb_node *unode;
1890         char *buf;
1891         size_t wanted_size = count * size;
1892
1893         spin_lock_init(&dlfb->urbs.lock);
1894
1895 retry:
1896         dlfb->urbs.size = size;
1897         INIT_LIST_HEAD(&dlfb->urbs.list);
1898
1899         sema_init(&dlfb->urbs.limit_sem, 0);
1900         dlfb->urbs.count = 0;
1901         dlfb->urbs.available = 0;
1902
1903         while (dlfb->urbs.count * size < wanted_size) {
1904                 unode = kzalloc(sizeof(*unode), GFP_KERNEL);
1905                 if (!unode)
1906                         break;
1907                 unode->dlfb = dlfb;
1908
1909                 urb = usb_alloc_urb(0, GFP_KERNEL);
1910                 if (!urb) {
1911                         kfree(unode);
1912                         break;
1913                 }
1914                 unode->urb = urb;
1915
1916                 buf = usb_alloc_coherent(dlfb->udev, size, GFP_KERNEL,
1917                                          &urb->transfer_dma);
1918                 if (!buf) {
1919                         kfree(unode);
1920                         usb_free_urb(urb);
1921                         if (size > PAGE_SIZE) {
1922                                 size /= 2;
1923                                 dlfb_free_urb_list(dlfb);
1924                                 goto retry;
1925                         }
1926                         break;
1927                 }
1928
1929                 /* urb->transfer_buffer_length set to actual before submit */
1930                 usb_fill_bulk_urb(urb, dlfb->udev, usb_sndbulkpipe(dlfb->udev, 1),
1931                         buf, size, dlfb_urb_completion, unode);
1932                 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
1933
1934                 list_add_tail(&unode->entry, &dlfb->urbs.list);
1935
1936                 up(&dlfb->urbs.limit_sem);
1937                 dlfb->urbs.count++;
1938                 dlfb->urbs.available++;
1939         }
1940
1941         return dlfb->urbs.count;
1942 }
1943
1944 static struct urb *dlfb_get_urb(struct dlfb_data *dlfb)
1945 {
1946         int ret;
1947         struct list_head *entry;
1948         struct urb_node *unode;
1949
1950         /* Wait for an in-flight buffer to complete and get re-queued */
1951         ret = down_timeout(&dlfb->urbs.limit_sem, GET_URB_TIMEOUT);
1952         if (ret) {
1953                 atomic_set(&dlfb->lost_pixels, 1);
1954                 dev_warn(&dlfb->udev->dev,
1955                          "wait for urb interrupted: %d available: %d\n",
1956                          ret, dlfb->urbs.available);
1957                 return NULL;
1958         }
1959
1960         spin_lock_irq(&dlfb->urbs.lock);
1961
1962         BUG_ON(list_empty(&dlfb->urbs.list)); /* reserved one with limit_sem */
1963         entry = dlfb->urbs.list.next;
1964         list_del_init(entry);
1965         dlfb->urbs.available--;
1966
1967         spin_unlock_irq(&dlfb->urbs.lock);
1968
1969         unode = list_entry(entry, struct urb_node, entry);
1970         return unode->urb;
1971 }
1972
1973 static int dlfb_submit_urb(struct dlfb_data *dlfb, struct urb *urb, size_t len)
1974 {
1975         int ret;
1976
1977         BUG_ON(len > dlfb->urbs.size);
1978
1979         urb->transfer_buffer_length = len; /* set to actual payload len */
1980         ret = usb_submit_urb(urb, GFP_KERNEL);
1981         if (ret) {
1982                 dlfb_urb_completion(urb); /* because no one else will */
1983                 atomic_set(&dlfb->lost_pixels, 1);
1984                 dev_err(&dlfb->udev->dev, "submit urb error: %d\n", ret);
1985         }
1986         return ret;
1987 }
1988
1989 module_param(console, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1990 MODULE_PARM_DESC(console, "Allow fbcon to open framebuffer");
1991
1992 module_param(fb_defio, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1993 MODULE_PARM_DESC(fb_defio, "Page fault detection of mmap writes");
1994
1995 module_param(shadow, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1996 MODULE_PARM_DESC(shadow, "Shadow vid mem. Disable to save mem but lose perf");
1997
1998 module_param(pixel_limit, int, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1999 MODULE_PARM_DESC(pixel_limit, "Force limit on max mode (in x*y pixels)");
2000
2001 MODULE_AUTHOR("Roberto De Ioris <roberto@unbit.it>, "
2002               "Jaya Kumar <jayakumar.lkml@gmail.com>, "
2003               "Bernie Thompson <bernie@plugable.com>");
2004 MODULE_DESCRIPTION("DisplayLink kernel framebuffer driver");
2005 MODULE_LICENSE("GPL");
2006