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