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 (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
 332                 return -EINVAL;
 333         if (size > info->fix.smem_len)
 334                 return -EINVAL;
 335         if (offset > info->fix.smem_len - size)
 336                 return -EINVAL;
 337
 338         pos = (unsigned long)info->fix.smem_start + offset;
 339
 340         dev_dbg(info->dev, "mmap() framebuffer addr:%lu size:%lu\n",
 341                 pos, size);
 342
 343         while (size > 0) {
 344                 page = vmalloc_to_pfn((void *)pos);
 345                 if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
 346                         return -EAGAIN;
 347
 348                 start += PAGE_SIZE;
 349                 pos += PAGE_SIZE;
 350                 if (size > PAGE_SIZE)
 351                         size -= PAGE_SIZE;
 352                 else
 353                         size = 0;
 354         }
 355
 356         return 0;
 357 }
 358
 359 /*
 360  * Trims identical data from front and back of line
 361  * Sets new front buffer address and width
 362  * And returns byte count of identical pixels
 363  * Assumes CPU natural alignment (unsigned long)
 364  * for back and front buffer ptrs and width
 365  */
 366 static int dlfb_trim_hline(const u8 *bback, const u8 **bfront, int *width_bytes)
 367 {
 368         int j, k;
 369         const unsigned long *back = (const unsigned long *) bback;
 370         const unsigned long *front = (const unsigned long *) *bfront;
 371         const int width = *width_bytes / sizeof(unsigned long);
 372         int identical = width;
 373         int start = width;
 374         int end = width;
 375
 376         for (j = 0; j < width; j++) {
 377                 if (back[j] != front[j]) {
 378                         start = j;
 379                         break;
 380                 }
 381         }
 382
 383         for (k = width - 1; k > j; k--) {
 384                 if (back[k] != front[k]) {
 385                         end = k+1;
 386                         break;
 387                 }
 388         }
 389
 390         identical = start + (width - end);
 391         *bfront = (u8 *) &front[start];
 392         *width_bytes = (end - start) * sizeof(unsigned long);
 393
 394         return identical * sizeof(unsigned long);
 395 }
 396
 397 /*
 398  * Render a command stream for an encoded horizontal line segment of pixels.
 399  *
 400  * A command buffer holds several commands.
 401  * It always begins with a fresh command header
 402  * (the protocol doesn't require this, but we enforce it to allow
 403  * multiple buffers to be potentially encoded and sent in parallel).
 404  * A single command encodes one contiguous horizontal line of pixels
 405  *
 406  * The function relies on the client to do all allocation, so that
 407  * rendering can be done directly to output buffers (e.g. USB URBs).
 408  * The function fills the supplied command buffer, providing information
 409  * on where it left off, so the client may call in again with additional
 410  * buffers if the line will take several buffers to complete.
 411  *
 412  * A single command can transmit a maximum of 256 pixels,
 413  * regardless of the compression ratio (protocol design limit).
 414  * To the hardware, 0 for a size byte means 256
 415  *
 416  * Rather than 256 pixel commands which are either rl or raw encoded,
 417  * the rlx command simply assumes alternating raw and rl spans within one cmd.
 418  * This has a slightly larger header overhead, but produces more even results.
 419  * It also processes all data (read and write) in a single pass.
 420  * Performance benchmarks of common cases show it having just slightly better
 421  * compression than 256 pixel raw or rle commands, with similar CPU consumpion.
 422  * But for very rl friendly data, will compress not quite as well.
 423  */
 424 static void dlfb_compress_hline(
 425         const uint16_t **pixel_start_ptr,
 426         const uint16_t *const pixel_end,
 427         uint32_t *device_address_ptr,
 428         uint8_t **command_buffer_ptr,
 429         const uint8_t *const cmd_buffer_end,
 430         unsigned long back_buffer_offset,
 431         int *ident_ptr)
 432 {
 433         const uint16_t *pixel = *pixel_start_ptr;
 434         uint32_t dev_addr  = *device_address_ptr;
 435         uint8_t *cmd = *command_buffer_ptr;
 436
 437         while ((pixel_end > pixel) &&
 438                (cmd_buffer_end - MIN_RLX_CMD_BYTES > cmd)) {
 439                 uint8_t *raw_pixels_count_byte = NULL;
 440                 uint8_t *cmd_pixels_count_byte = NULL;
 441                 const uint16_t *raw_pixel_start = NULL;
 442                 const uint16_t *cmd_pixel_start, *cmd_pixel_end = NULL;
 443
 444                 if (back_buffer_offset &&
 445                     *pixel == *(u16 *)((u8 *)pixel + back_buffer_offset)) {
 446                         pixel++;
 447                         dev_addr += BPP;
 448                         (*ident_ptr)++;
 449                         continue;
 450                 }
 451
 452                 *cmd++ = 0xAF;
 453                 *cmd++ = 0x6B;
 454                 *cmd++ = dev_addr >> 16;
 455                 *cmd++ = dev_addr >> 8;
 456                 *cmd++ = dev_addr;
 457
 458                 cmd_pixels_count_byte = cmd++; /*  we'll know this later */
 459                 cmd_pixel_start = pixel;
 460
 461                 raw_pixels_count_byte = cmd++; /*  we'll know this later */
 462                 raw_pixel_start = pixel;
 463
 464                 cmd_pixel_end = pixel + min3(MAX_CMD_PIXELS + 1UL,
 465                                         (unsigned long)(pixel_end - pixel),
 466                                         (unsigned long)(cmd_buffer_end - 1 - cmd) / BPP);
 467
 468                 if (back_buffer_offset) {
 469                         /* note: the framebuffer may change under us, so we must test for underflow */
 470                         while (cmd_pixel_end - 1 > pixel &&
 471                                *(cmd_pixel_end - 1) == *(u16 *)((u8 *)(cmd_pixel_end - 1) + back_buffer_offset))
 472                                 cmd_pixel_end--;
 473                 }
 474
 475                 while (pixel < cmd_pixel_end) {
 476                         const uint16_t * const repeating_pixel = pixel;
 477                         u16 pixel_value = *pixel;
 478
 479                         put_unaligned_be16(pixel_value, cmd);
 480                         if (back_buffer_offset)
 481                                 *(u16 *)((u8 *)pixel + back_buffer_offset) = pixel_value;
 482                         cmd += 2;
 483                         pixel++;
 484
 485                         if (unlikely((pixel < cmd_pixel_end) &&
 486                                      (*pixel == pixel_value))) {
 487                                 /* go back and fill in raw pixel count */
 488                                 *raw_pixels_count_byte = ((repeating_pixel -
 489                                                 raw_pixel_start) + 1) & 0xFF;
 490
 491                                 do {
 492                                         if (back_buffer_offset)
 493                                                 *(u16 *)((u8 *)pixel + back_buffer_offset) = pixel_value;
 494                                         pixel++;
 495                                 } while ((pixel < cmd_pixel_end) &&
 496                                          (*pixel == pixel_value));
 497
 498                                 /* immediately after raw data is repeat byte */
 499                                 *cmd++ = ((pixel - repeating_pixel) - 1) & 0xFF;
 500
 501                                 /* Then start another raw pixel span */
 502                                 raw_pixel_start = pixel;
 503                                 raw_pixels_count_byte = cmd++;
 504                         }
 505                 }
 506
 507                 if (pixel > raw_pixel_start) {
 508                         /* finalize last RAW span */
 509                         *raw_pixels_count_byte = (pixel-raw_pixel_start) & 0xFF;
 510                 } else {
 511                         /* undo unused byte */
 512                         cmd--;
 513                 }
 514
 515                 *cmd_pixels_count_byte = (pixel - cmd_pixel_start) & 0xFF;
 516                 dev_addr += (u8 *)pixel - (u8 *)cmd_pixel_start;
 517         }
 518
 519         if (cmd_buffer_end - MIN_RLX_CMD_BYTES <= cmd) {
 520                 /* Fill leftover bytes with no-ops */
 521                 if (cmd_buffer_end > cmd)
 522                         memset(cmd, 0xAF, cmd_buffer_end - cmd);
 523                 cmd = (uint8_t *) cmd_buffer_end;
 524         }
 525
 526         *command_buffer_ptr = cmd;
 527         *pixel_start_ptr = pixel;
 528         *device_address_ptr = dev_addr;
 529 }
 530
 531 /*
 532  * There are 3 copies of every pixel: The front buffer that the fbdev
 533  * client renders to, the actual framebuffer across the USB bus in hardware
 534  * (that we can only write to, slowly, and can never read), and (optionally)
 535  * our shadow copy that tracks what's been sent to that hardware buffer.
 536  */
 537 static int dlfb_render_hline(struct dlfb_data *dlfb, struct urb **urb_ptr,
 538                               const char *front, char **urb_buf_ptr,
 539                               u32 byte_offset, u32 byte_width,
 540                               int *ident_ptr, int *sent_ptr)
 541 {
 542         const u8 *line_start, *line_end, *next_pixel;
 543         u32 dev_addr = dlfb->base16 + byte_offset;
 544         struct urb *urb = *urb_ptr;
 545         u8 *cmd = *urb_buf_ptr;
 546         u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
 547         unsigned long back_buffer_offset = 0;
 548
 549         line_start = (u8 *) (front + byte_offset);
 550         next_pixel = line_start;
 551         line_end = next_pixel + byte_width;
 552
 553         if (dlfb->backing_buffer) {
 554                 int offset;
 555                 const u8 *back_start = (u8 *) (dlfb->backing_buffer
 556                                                 + byte_offset);
 557
 558                 back_buffer_offset = (unsigned long)back_start - (unsigned long)line_start;
 559
 560                 *ident_ptr += dlfb_trim_hline(back_start, &next_pixel,
 561                         &byte_width);
 562
 563                 offset = next_pixel - line_start;
 564                 line_end = next_pixel + byte_width;
 565                 dev_addr += offset;
 566                 back_start += offset;
 567                 line_start += offset;
 568         }
 569
 570         while (next_pixel < line_end) {
 571
 572                 dlfb_compress_hline((const uint16_t **) &next_pixel,
 573                              (const uint16_t *) line_end, &dev_addr,
 574                         (u8 **) &cmd, (u8 *) cmd_end, back_buffer_offset,
 575                         ident_ptr);
 576
 577                 if (cmd >= cmd_end) {
 578                         int len = cmd - (u8 *) urb->transfer_buffer;
 579                         if (dlfb_submit_urb(dlfb, urb, len))
 580                                 return 1; /* lost pixels is set */
 581                         *sent_ptr += len;
 582                         urb = dlfb_get_urb(dlfb);
 583                         if (!urb)
 584                                 return 1; /* lost_pixels is set */
 585                         *urb_ptr = urb;
 586                         cmd = urb->transfer_buffer;
 587                         cmd_end = &cmd[urb->transfer_buffer_length];
 588                 }
 589         }
 590
 591         *urb_buf_ptr = cmd;
 592
 593         return 0;
 594 }
 595
 596 static int dlfb_handle_damage(struct dlfb_data *dlfb, int x, int y, int width, int height)
 597 {
 598         int i, ret;
 599         char *cmd;
 600         cycles_t start_cycles, end_cycles;
 601         int bytes_sent = 0;
 602         int bytes_identical = 0;
 603         struct urb *urb;
 604         int aligned_x;
 605
 606         start_cycles = get_cycles();
 607
 608         mutex_lock(&dlfb->render_mutex);
 609
 610         aligned_x = DL_ALIGN_DOWN(x, sizeof(unsigned long));
 611         width = DL_ALIGN_UP(width + (x-aligned_x), sizeof(unsigned long));
 612         x = aligned_x;
 613
 614         if ((width <= 0) ||
 615             (x + width > dlfb->info->var.xres) ||
 616             (y + height > dlfb->info->var.yres)) {
 617                 ret = -EINVAL;
 618                 goto unlock_ret;
 619         }
 620
 621         if (!atomic_read(&dlfb->usb_active)) {
 622                 ret = 0;
 623                 goto unlock_ret;
 624         }
 625
 626         urb = dlfb_get_urb(dlfb);
 627         if (!urb) {
 628                 ret = 0;
 629                 goto unlock_ret;
 630         }
 631         cmd = urb->transfer_buffer;
 632
 633         for (i = y; i < y + height ; i++) {
 634                 const int line_offset = dlfb->info->fix.line_length * i;
 635                 const int byte_offset = line_offset + (x * BPP);
 636
 637                 if (dlfb_render_hline(dlfb, &urb,
 638                                       (char *) dlfb->info->fix.smem_start,
 639                                       &cmd, byte_offset, width * BPP,
 640                                       &bytes_identical, &bytes_sent))
 641                         goto error;
 642         }
 643
 644         if (cmd > (char *) urb->transfer_buffer) {
 645                 int len;
 646                 if (cmd < (char *) urb->transfer_buffer + urb->transfer_buffer_length)
 647                         *cmd++ = 0xAF;
 648                 /* Send partial buffer remaining before exiting */
 649                 len = cmd - (char *) urb->transfer_buffer;
 650                 dlfb_submit_urb(dlfb, urb, len);
 651                 bytes_sent += len;
 652         } else
 653                 dlfb_urb_completion(urb);
 654
 655 error:
 656         atomic_add(bytes_sent, &dlfb->bytes_sent);
 657         atomic_add(bytes_identical, &dlfb->bytes_identical);
 658         atomic_add(width*height*2, &dlfb->bytes_rendered);
 659         end_cycles = get_cycles();
 660         atomic_add(((unsigned int) ((end_cycles - start_cycles)
 661                     >> 10)), /* Kcycles */
 662                    &dlfb->cpu_kcycles_used);
 663
 664         ret = 0;
 665
 666 unlock_ret:
 667         mutex_unlock(&dlfb->render_mutex);
 668         return ret;
 669 }
 670
 671 static void dlfb_init_damage(struct dlfb_data *dlfb)
 672 {
 673         dlfb->damage_x = INT_MAX;
 674         dlfb->damage_x2 = 0;
 675         dlfb->damage_y = INT_MAX;
 676         dlfb->damage_y2 = 0;
 677 }
 678
 679 static void dlfb_damage_work(struct work_struct *w)
 680 {
 681         struct dlfb_data *dlfb = container_of(w, struct dlfb_data, damage_work);
 682         int x, x2, y, y2;
 683
 684         spin_lock_irq(&dlfb->damage_lock);
 685         x = dlfb->damage_x;
 686         x2 = dlfb->damage_x2;
 687         y = dlfb->damage_y;
 688         y2 = dlfb->damage_y2;
 689         dlfb_init_damage(dlfb);
 690         spin_unlock_irq(&dlfb->damage_lock);
 691
 692         if (x < x2 && y < y2)
 693                 dlfb_handle_damage(dlfb, x, y, x2 - x, y2 - y);
 694 }
 695
 696 static void dlfb_offload_damage(struct dlfb_data *dlfb, int x, int y, int width, int height)
 697 {
 698         unsigned long flags;
 699         int x2 = x + width;
 700         int y2 = y + height;
 701
 702         if (x >= x2 || y >= y2)
 703                 return;
 704
 705         spin_lock_irqsave(&dlfb->damage_lock, flags);
 706         dlfb->damage_x = min(x, dlfb->damage_x);
 707         dlfb->damage_x2 = max(x2, dlfb->damage_x2);
 708         dlfb->damage_y = min(y, dlfb->damage_y);
 709         dlfb->damage_y2 = max(y2, dlfb->damage_y2);
 710         spin_unlock_irqrestore(&dlfb->damage_lock, flags);
 711
 712         schedule_work(&dlfb->damage_work);
 713 }
 714
 715 /*
 716  * Path triggered by usermode clients who write to filesystem
 717  * e.g. cat filename > /dev/fb1
 718  * Not used by X Windows or text-mode console. But useful for testing.
 719  * Slow because of extra copy and we must assume all pixels dirty.
 720  */
 721 static ssize_t dlfb_ops_write(struct fb_info *info, const char __user *buf,
 722                           size_t count, loff_t *ppos)
 723 {
 724         ssize_t result;
 725         struct dlfb_data *dlfb = info->par;
 726         u32 offset = (u32) *ppos;
 727
 728         result = fb_sys_write(info, buf, count, ppos);
 729
 730         if (result > 0) {
 731                 int start = max((int)(offset / info->fix.line_length), 0);
 732                 int lines = min((u32)((result / info->fix.line_length) + 1),
 733                                 (u32)info->var.yres);
 734
 735                 dlfb_handle_damage(dlfb, 0, start, info->var.xres,
 736                         lines);
 737         }
 738
 739         return result;
 740 }
 741
 742 /* hardware has native COPY command (see libdlo), but not worth it for fbcon */
 743 static void dlfb_ops_copyarea(struct fb_info *info,
 744                                 const struct fb_copyarea *area)
 745 {
 746
 747         struct dlfb_data *dlfb = info->par;
 748
 749         sys_copyarea(info, area);
 750
 751         dlfb_offload_damage(dlfb, area->dx, area->dy,
 752                         area->width, area->height);
 753 }
 754
 755 static void dlfb_ops_imageblit(struct fb_info *info,
 756                                 const struct fb_image *image)
 757 {
 758         struct dlfb_data *dlfb = info->par;
 759
 760         sys_imageblit(info, image);
 761
 762         dlfb_offload_damage(dlfb, image->dx, image->dy,
 763                         image->width, image->height);
 764 }
 765
 766 static void dlfb_ops_fillrect(struct fb_info *info,
 767                           const struct fb_fillrect *rect)
 768 {
 769         struct dlfb_data *dlfb = info->par;
 770
 771         sys_fillrect(info, rect);
 772
 773         dlfb_offload_damage(dlfb, rect->dx, rect->dy, rect->width,
 774                               rect->height);
 775 }
 776
 777 /*
 778  * NOTE: fb_defio.c is holding info->fbdefio.mutex
 779  *   Touching ANY framebuffer memory that triggers a page fault
 780  *   in fb_defio will cause a deadlock, when it also tries to
 781  *   grab the same mutex.
 782  */
 783 static void dlfb_dpy_deferred_io(struct fb_info *info,
 784                                 struct list_head *pagelist)
 785 {
 786         struct page *cur;
 787         struct fb_deferred_io *fbdefio = info->fbdefio;
 788         struct dlfb_data *dlfb = info->par;
 789         struct urb *urb;
 790         char *cmd;
 791         cycles_t start_cycles, end_cycles;
 792         int bytes_sent = 0;
 793         int bytes_identical = 0;
 794         int bytes_rendered = 0;
 795
 796         mutex_lock(&dlfb->render_mutex);
 797
 798         if (!fb_defio)
 799                 goto unlock_ret;
 800
 801         if (!atomic_read(&dlfb->usb_active))
 802                 goto unlock_ret;
 803
 804         start_cycles = get_cycles();
 805
 806         urb = dlfb_get_urb(dlfb);
 807         if (!urb)
 808                 goto unlock_ret;
 809
 810         cmd = urb->transfer_buffer;
 811
 812         /* walk the written page list and render each to device */
 813         list_for_each_entry(cur, &fbdefio->pagelist, lru) {
 814
 815                 if (dlfb_render_hline(dlfb, &urb, (char *) info->fix.smem_start,
 816                                   &cmd, cur->index << PAGE_SHIFT,
 817                                   PAGE_SIZE, &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->deferred_io = dlfb_dpy_deferred_io;
 986                 }
 987
 988                 info->fbdefio = fbdefio;
 989                 fb_deferred_io_init(info);
 990         }
 991
 992         dev_dbg(info->dev, "open, user=%d fb_info=%p count=%d\n",
 993                 user, info, dlfb->fb_count);
 994
 995         return 0;
 996 }
 997
 998 static void dlfb_ops_destroy(struct fb_info *info)
 999 {
1000         struct dlfb_data *dlfb = info->par;
1001
1002         cancel_work_sync(&dlfb->damage_work);
1003
1004         mutex_destroy(&dlfb->render_mutex);
1005
1006         if (info->cmap.len != 0)
1007                 fb_dealloc_cmap(&info->cmap);
1008         if (info->monspecs.modedb)
1009                 fb_destroy_modedb(info->monspecs.modedb);
1010         vfree(info->screen_base);
1011
1012         fb_destroy_modelist(&info->modelist);
1013
1014         while (!list_empty(&dlfb->deferred_free)) {
1015                 struct dlfb_deferred_free *d = list_entry(dlfb->deferred_free.next, struct dlfb_deferred_free, list);
1016                 list_del(&d->list);
1017                 vfree(d->mem);
1018                 kfree(d);
1019         }
1020         vfree(dlfb->backing_buffer);
1021         kfree(dlfb->edid);
1022         dlfb_free_urb_list(dlfb);
1023         usb_put_dev(dlfb->udev);
1024         kfree(dlfb);
1025
1026         /* Assume info structure is freed after this point */
1027         framebuffer_release(info);
1028 }
1029
1030 /*
1031  * Assumes caller is holding info->lock mutex (for open and release at least)
1032  */
1033 static int dlfb_ops_release(struct fb_info *info, int user)
1034 {
1035         struct dlfb_data *dlfb = info->par;
1036
1037         dlfb->fb_count--;
1038
1039         if ((dlfb->fb_count == 0) && (info->fbdefio)) {
1040                 fb_deferred_io_cleanup(info);
1041                 kfree(info->fbdefio);
1042                 info->fbdefio = NULL;
1043         }
1044
1045         dev_dbg(info->dev, "release, user=%d count=%d\n", user, dlfb->fb_count);
1046
1047         return 0;
1048 }
1049
1050 /*
1051  * Check whether a video mode is supported by the DisplayLink chip
1052  * We start from monitor's modes, so don't need to filter that here
1053  */
1054 static int dlfb_is_valid_mode(struct fb_videomode *mode, struct dlfb_data *dlfb)
1055 {
1056         if (mode->xres * mode->yres > dlfb->sku_pixel_limit)
1057                 return 0;
1058
1059         return 1;
1060 }
1061
1062 static void dlfb_var_color_format(struct fb_var_screeninfo *var)
1063 {
1064         const struct fb_bitfield red = { 11, 5, 0 };
1065         const struct fb_bitfield green = { 5, 6, 0 };
1066         const struct fb_bitfield blue = { 0, 5, 0 };
1067
1068         var->bits_per_pixel = 16;
1069         var->red = red;
1070         var->green = green;
1071         var->blue = blue;
1072 }
1073
1074 static int dlfb_ops_check_var(struct fb_var_screeninfo *var,
1075                                 struct fb_info *info)
1076 {
1077         struct fb_videomode mode;
1078         struct dlfb_data *dlfb = info->par;
1079
1080         /* set device-specific elements of var unrelated to mode */
1081         dlfb_var_color_format(var);
1082
1083         fb_var_to_videomode(&mode, var);
1084
1085         if (!dlfb_is_valid_mode(&mode, dlfb))
1086                 return -EINVAL;
1087
1088         return 0;
1089 }
1090
1091 static int dlfb_ops_set_par(struct fb_info *info)
1092 {
1093         struct dlfb_data *dlfb = info->par;
1094         int result;
1095         u16 *pix_framebuffer;
1096         int i;
1097         struct fb_var_screeninfo fvs;
1098         u32 line_length = info->var.xres * (info->var.bits_per_pixel / 8);
1099
1100         /* clear the activate field because it causes spurious miscompares */
1101         fvs = info->var;
1102         fvs.activate = 0;
1103         fvs.vmode &= ~FB_VMODE_SMOOTH_XPAN;
1104
1105         if (!memcmp(&dlfb->current_mode, &fvs, sizeof(struct fb_var_screeninfo)))
1106                 return 0;
1107
1108         result = dlfb_realloc_framebuffer(dlfb, info, info->var.yres * line_length);
1109         if (result)
1110                 return result;
1111
1112         result = dlfb_set_video_mode(dlfb, &info->var);
1113
1114         if (result)
1115                 return result;
1116
1117         dlfb->current_mode = fvs;
1118         info->fix.line_length = line_length;
1119
1120         if (dlfb->fb_count == 0) {
1121
1122                 /* paint greenscreen */
1123
1124                 pix_framebuffer = (u16 *) info->screen_base;
1125                 for (i = 0; i < info->fix.smem_len / 2; i++)
1126                         pix_framebuffer[i] = 0x37e6;
1127         }
1128
1129         dlfb_handle_damage(dlfb, 0, 0, info->var.xres, info->var.yres);
1130
1131         return 0;
1132 }
1133
1134 /* To fonzi the jukebox (e.g. make blanking changes take effect) */
1135 static char *dlfb_dummy_render(char *buf)
1136 {
1137         *buf++ = 0xAF;
1138         *buf++ = 0x6A; /* copy */
1139         *buf++ = 0x00; /* from address*/
1140         *buf++ = 0x00;
1141         *buf++ = 0x00;
1142         *buf++ = 0x01; /* one pixel */
1143         *buf++ = 0x00; /* to address */
1144         *buf++ = 0x00;
1145         *buf++ = 0x00;
1146         return buf;
1147 }
1148
1149 /*
1150  * In order to come back from full DPMS off, we need to set the mode again
1151  */
1152 static int dlfb_ops_blank(int blank_mode, struct fb_info *info)
1153 {
1154         struct dlfb_data *dlfb = info->par;
1155         char *bufptr;
1156         struct urb *urb;
1157
1158         dev_dbg(info->dev, "blank, mode %d --> %d\n",
1159                 dlfb->blank_mode, blank_mode);
1160
1161         if ((dlfb->blank_mode == FB_BLANK_POWERDOWN) &&
1162             (blank_mode != FB_BLANK_POWERDOWN)) {
1163
1164                 /* returning from powerdown requires a fresh modeset */
1165                 dlfb_set_video_mode(dlfb, &info->var);
1166         }
1167
1168         urb = dlfb_get_urb(dlfb);
1169         if (!urb)
1170                 return 0;
1171
1172         bufptr = (char *) urb->transfer_buffer;
1173         bufptr = dlfb_vidreg_lock(bufptr);
1174         bufptr = dlfb_blanking(bufptr, blank_mode);
1175         bufptr = dlfb_vidreg_unlock(bufptr);
1176
1177         /* seems like a render op is needed to have blank change take effect */
1178         bufptr = dlfb_dummy_render(bufptr);
1179
1180         dlfb_submit_urb(dlfb, urb, bufptr -
1181                         (char *) urb->transfer_buffer);
1182
1183         dlfb->blank_mode = blank_mode;
1184
1185         return 0;
1186 }
1187
1188 static const struct fb_ops dlfb_ops = {
1189         .owner = THIS_MODULE,
1190         .fb_read = fb_sys_read,
1191         .fb_write = dlfb_ops_write,
1192         .fb_setcolreg = dlfb_ops_setcolreg,
1193         .fb_fillrect = dlfb_ops_fillrect,
1194         .fb_copyarea = dlfb_ops_copyarea,
1195         .fb_imageblit = dlfb_ops_imageblit,
1196         .fb_mmap = dlfb_ops_mmap,
1197         .fb_ioctl = dlfb_ops_ioctl,
1198         .fb_open = dlfb_ops_open,
1199         .fb_release = dlfb_ops_release,
1200         .fb_blank = dlfb_ops_blank,
1201         .fb_check_var = dlfb_ops_check_var,
1202         .fb_set_par = dlfb_ops_set_par,
1203         .fb_destroy = dlfb_ops_destroy,
1204 };
1205
1206
1207 static void dlfb_deferred_vfree(struct dlfb_data *dlfb, void *mem)
1208 {
1209         struct dlfb_deferred_free *d = kmalloc(sizeof(struct dlfb_deferred_free), GFP_KERNEL);
1210         if (!d)
1211                 return;
1212         d->mem = mem;
1213         list_add(&d->list, &dlfb->deferred_free);
1214 }
1215
1216 /*
1217  * Assumes &info->lock held by caller
1218  * Assumes no active clients have framebuffer open
1219  */
1220 static int dlfb_realloc_framebuffer(struct dlfb_data *dlfb, struct fb_info *info, u32 new_len)
1221 {
1222         u32 old_len = info->fix.smem_len;
1223         const void *old_fb = (const void __force *)info->screen_base;
1224         unsigned char *new_fb;
1225         unsigned char *new_back = NULL;
1226
1227         new_len = PAGE_ALIGN(new_len);
1228
1229         if (new_len > old_len) {
1230                 /*
1231                  * Alloc system memory for virtual framebuffer
1232                  */
1233                 new_fb = vmalloc(new_len);
1234                 if (!new_fb) {
1235                         dev_err(info->dev, "Virtual framebuffer alloc failed\n");
1236                         return -ENOMEM;
1237                 }
1238                 memset(new_fb, 0xff, new_len);
1239
1240                 if (info->screen_base) {
1241                         memcpy(new_fb, old_fb, old_len);
1242                         dlfb_deferred_vfree(dlfb, (void __force *)info->screen_base);
1243                 }
1244
1245                 info->screen_base = (char __iomem *)new_fb;
1246                 info->fix.smem_len = new_len;
1247                 info->fix.smem_start = (unsigned long) new_fb;
1248                 info->flags = udlfb_info_flags;
1249
1250                 /*
1251                  * Second framebuffer copy to mirror the framebuffer state
1252                  * on the physical USB device. We can function without this.
1253                  * But with imperfect damage info we may send pixels over USB
1254                  * that were, in fact, unchanged - wasting limited USB bandwidth
1255                  */
1256                 if (shadow)
1257                         new_back = vzalloc(new_len);
1258                 if (!new_back)
1259                         dev_info(info->dev,
1260                                  "No shadow/backing buffer allocated\n");
1261                 else {
1262                         dlfb_deferred_vfree(dlfb, dlfb->backing_buffer);
1263                         dlfb->backing_buffer = new_back;
1264                 }
1265         }
1266         return 0;
1267 }
1268
1269 /*
1270  * 1) Get EDID from hw, or use sw default
1271  * 2) Parse into various fb_info structs
1272  * 3) Allocate virtual framebuffer memory to back highest res mode
1273  *
1274  * Parses EDID into three places used by various parts of fbdev:
1275  * fb_var_screeninfo contains the timing of the monitor's preferred mode
1276  * fb_info.monspecs is full parsed EDID info, including monspecs.modedb
1277  * fb_info.modelist is a linked list of all monitor & VESA modes which work
1278  *
1279  * If EDID is not readable/valid, then modelist is all VESA modes,
1280  * monspecs is NULL, and fb_var_screeninfo is set to safe VESA mode
1281  * Returns 0 if successful
1282  */
1283 static int dlfb_setup_modes(struct dlfb_data *dlfb,
1284                            struct fb_info *info,
1285                            char *default_edid, size_t default_edid_size)
1286 {
1287         char *edid;
1288         int i, result = 0, tries = 3;
1289         struct device *dev = info->device;
1290         struct fb_videomode *mode;
1291         const struct fb_videomode *default_vmode = NULL;
1292
1293         if (info->dev) {
1294                 /* only use mutex if info has been registered */
1295                 mutex_lock(&info->lock);
1296                 /* parent device is used otherwise */
1297                 dev = info->dev;
1298         }
1299
1300         edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
1301         if (!edid) {
1302                 result = -ENOMEM;
1303                 goto error;
1304         }
1305
1306         fb_destroy_modelist(&info->modelist);
1307         memset(&info->monspecs, 0, sizeof(info->monspecs));
1308
1309         /*
1310          * Try to (re)read EDID from hardware first
1311          * EDID data may return, but not parse as valid
1312          * Try again a few times, in case of e.g. analog cable noise
1313          */
1314         while (tries--) {
1315
1316                 i = dlfb_get_edid(dlfb, edid, EDID_LENGTH);
1317
1318                 if (i >= EDID_LENGTH)
1319                         fb_edid_to_monspecs(edid, &info->monspecs);
1320
1321                 if (info->monspecs.modedb_len > 0) {
1322                         dlfb->edid = edid;
1323                         dlfb->edid_size = i;
1324                         break;
1325                 }
1326         }
1327
1328         /* If that fails, use a previously returned EDID if available */
1329         if (info->monspecs.modedb_len == 0) {
1330                 dev_err(dev, "Unable to get valid EDID from device/display\n");
1331
1332                 if (dlfb->edid) {
1333                         fb_edid_to_monspecs(dlfb->edid, &info->monspecs);
1334                         if (info->monspecs.modedb_len > 0)
1335                                 dev_err(dev, "Using previously queried EDID\n");
1336                 }
1337         }
1338
1339         /* If that fails, use the default EDID we were handed */
1340         if (info->monspecs.modedb_len == 0) {
1341                 if (default_edid_size >= EDID_LENGTH) {
1342                         fb_edid_to_monspecs(default_edid, &info->monspecs);
1343                         if (info->monspecs.modedb_len > 0) {
1344                                 memcpy(edid, default_edid, default_edid_size);
1345                                 dlfb->edid = edid;
1346                                 dlfb->edid_size = default_edid_size;
1347                                 dev_err(dev, "Using default/backup EDID\n");
1348                         }
1349                 }
1350         }
1351
1352         /* If we've got modes, let's pick a best default mode */
1353         if (info->monspecs.modedb_len > 0) {
1354
1355                 for (i = 0; i < info->monspecs.modedb_len; i++) {
1356                         mode = &info->monspecs.modedb[i];
1357                         if (dlfb_is_valid_mode(mode, dlfb)) {
1358                                 fb_add_videomode(mode, &info->modelist);
1359                         } else {
1360                                 dev_dbg(dev, "Specified mode %dx%d too big\n",
1361                                         mode->xres, mode->yres);
1362                                 if (i == 0)
1363                                         /* if we've removed top/best mode */
1364                                         info->monspecs.misc
1365                                                 &= ~FB_MISC_1ST_DETAIL;
1366                         }
1367                 }
1368
1369                 default_vmode = fb_find_best_display(&info->monspecs,
1370                                                      &info->modelist);
1371         }
1372
1373         /* If everything else has failed, fall back to safe default mode */
1374         if (default_vmode == NULL) {
1375
1376                 struct fb_videomode fb_vmode = {0};
1377
1378                 /*
1379                  * Add the standard VESA modes to our modelist
1380                  * Since we don't have EDID, there may be modes that
1381                  * overspec monitor and/or are incorrect aspect ratio, etc.
1382                  * But at least the user has a chance to choose
1383                  */
1384                 for (i = 0; i < VESA_MODEDB_SIZE; i++) {
1385                         mode = (struct fb_videomode *)&vesa_modes[i];
1386                         if (dlfb_is_valid_mode(mode, dlfb))
1387                                 fb_add_videomode(mode, &info->modelist);
1388                         else
1389                                 dev_dbg(dev, "VESA mode %dx%d too big\n",
1390                                         mode->xres, mode->yres);
1391                 }
1392
1393                 /*
1394                  * default to resolution safe for projectors
1395                  * (since they are most common case without EDID)
1396                  */
1397                 fb_vmode.xres = 800;
1398                 fb_vmode.yres = 600;
1399                 fb_vmode.refresh = 60;
1400                 default_vmode = fb_find_nearest_mode(&fb_vmode,
1401                                                      &info->modelist);
1402         }
1403
1404         /* If we have good mode and no active clients*/
1405         if ((default_vmode != NULL) && (dlfb->fb_count == 0)) {
1406
1407                 fb_videomode_to_var(&info->var, default_vmode);
1408                 dlfb_var_color_format(&info->var);
1409
1410                 /*
1411                  * with mode size info, we can now alloc our framebuffer.
1412                  */
1413                 memcpy(&info->fix, &dlfb_fix, sizeof(dlfb_fix));
1414         } else
1415                 result = -EINVAL;
1416
1417 error:
1418         if (edid && (dlfb->edid != edid))
1419                 kfree(edid);
1420
1421         if (info->dev)
1422                 mutex_unlock(&info->lock);
1423
1424         return result;
1425 }
1426
1427 static ssize_t metrics_bytes_rendered_show(struct device *fbdev,
1428                                    struct device_attribute *a, char *buf) {
1429         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1430         struct dlfb_data *dlfb = fb_info->par;
1431         return sysfs_emit(buf, "%u\n",
1432                         atomic_read(&dlfb->bytes_rendered));
1433 }
1434
1435 static ssize_t metrics_bytes_identical_show(struct device *fbdev,
1436                                    struct device_attribute *a, char *buf) {
1437         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1438         struct dlfb_data *dlfb = fb_info->par;
1439         return sysfs_emit(buf, "%u\n",
1440                         atomic_read(&dlfb->bytes_identical));
1441 }
1442
1443 static ssize_t metrics_bytes_sent_show(struct device *fbdev,
1444                                    struct device_attribute *a, char *buf) {
1445         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1446         struct dlfb_data *dlfb = fb_info->par;
1447         return sysfs_emit(buf, "%u\n",
1448                         atomic_read(&dlfb->bytes_sent));
1449 }
1450
1451 static ssize_t metrics_cpu_kcycles_used_show(struct device *fbdev,
1452                                    struct device_attribute *a, char *buf) {
1453         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1454         struct dlfb_data *dlfb = fb_info->par;
1455         return sysfs_emit(buf, "%u\n",
1456                         atomic_read(&dlfb->cpu_kcycles_used));
1457 }
1458
1459 static ssize_t edid_show(
1460                         struct file *filp,
1461                         struct kobject *kobj, struct bin_attribute *a,
1462                          char *buf, loff_t off, size_t count) {
1463         struct device *fbdev = kobj_to_dev(kobj);
1464         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1465         struct dlfb_data *dlfb = fb_info->par;
1466
1467         if (dlfb->edid == NULL)
1468                 return 0;
1469
1470         if ((off >= dlfb->edid_size) || (count > dlfb->edid_size))
1471                 return 0;
1472
1473         if (off + count > dlfb->edid_size)
1474                 count = dlfb->edid_size - off;
1475
1476         memcpy(buf, dlfb->edid, count);
1477
1478         return count;
1479 }
1480
1481 static ssize_t edid_store(
1482                         struct file *filp,
1483                         struct kobject *kobj, struct bin_attribute *a,
1484                         char *src, loff_t src_off, size_t src_size) {
1485         struct device *fbdev = kobj_to_dev(kobj);
1486         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1487         struct dlfb_data *dlfb = fb_info->par;
1488         int ret;
1489
1490         /* We only support write of entire EDID at once, no offset*/
1491         if ((src_size != EDID_LENGTH) || (src_off != 0))
1492                 return -EINVAL;
1493
1494         ret = dlfb_setup_modes(dlfb, fb_info, src, src_size);
1495         if (ret)
1496                 return ret;
1497
1498         if (!dlfb->edid || memcmp(src, dlfb->edid, src_size))
1499                 return -EINVAL;
1500
1501         ret = dlfb_ops_set_par(fb_info);
1502         if (ret)
1503                 return ret;
1504
1505         return src_size;
1506 }
1507
1508 static ssize_t metrics_reset_store(struct device *fbdev,
1509                            struct device_attribute *attr,
1510                            const char *buf, size_t count)
1511 {
1512         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1513         struct dlfb_data *dlfb = fb_info->par;
1514
1515         atomic_set(&dlfb->bytes_rendered, 0);
1516         atomic_set(&dlfb->bytes_identical, 0);
1517         atomic_set(&dlfb->bytes_sent, 0);
1518         atomic_set(&dlfb->cpu_kcycles_used, 0);
1519
1520         return count;
1521 }
1522
1523 static const struct bin_attribute edid_attr = {
1524         .attr.name = "edid",
1525         .attr.mode = 0666,
1526         .size = EDID_LENGTH,
1527         .read = edid_show,
1528         .write = edid_store
1529 };
1530
1531 static const struct device_attribute fb_device_attrs[] = {
1532         __ATTR_RO(metrics_bytes_rendered),
1533         __ATTR_RO(metrics_bytes_identical),
1534         __ATTR_RO(metrics_bytes_sent),
1535         __ATTR_RO(metrics_cpu_kcycles_used),
1536         __ATTR(metrics_reset, S_IWUSR, NULL, metrics_reset_store),
1537 };
1538
1539 /*
1540  * This is necessary before we can communicate with the display controller.
1541  */
1542 static int dlfb_select_std_channel(struct dlfb_data *dlfb)
1543 {
1544         int ret;
1545         void *buf;
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         buf = kmemdup(set_def_chn, sizeof(set_def_chn), GFP_KERNEL);
1553
1554         if (!buf)
1555                 return -ENOMEM;
1556
1557         ret = usb_control_msg(dlfb->udev, usb_sndctrlpipe(dlfb->udev, 0),
1558                         NR_USB_REQUEST_CHANNEL,
1559                         (USB_DIR_OUT | USB_TYPE_VENDOR), 0, 0,
1560                         buf, sizeof(set_def_chn), USB_CTRL_SET_TIMEOUT);
1561
1562         kfree(buf);
1563
1564         return ret;
1565 }
1566
1567 static int dlfb_parse_vendor_descriptor(struct dlfb_data *dlfb,
1568                                         struct usb_interface *intf)
1569 {
1570         char *desc;
1571         char *buf;
1572         char *desc_end;
1573         int total_len;
1574
1575         buf = kzalloc(MAX_VENDOR_DESCRIPTOR_SIZE, GFP_KERNEL);
1576         if (!buf)
1577                 return false;
1578         desc = buf;
1579
1580         total_len = usb_get_descriptor(interface_to_usbdev(intf),
1581                                         0x5f, /* vendor specific */
1582                                         0, desc, MAX_VENDOR_DESCRIPTOR_SIZE);
1583
1584         /* if not found, look in configuration descriptor */
1585         if (total_len < 0) {
1586                 if (0 == usb_get_extra_descriptor(intf->cur_altsetting,
1587                         0x5f, &desc))
1588                         total_len = (int) desc[0];
1589         }
1590
1591         if (total_len > 5) {
1592                 dev_info(&intf->dev,
1593                          "vendor descriptor length: %d data: %11ph\n",
1594                          total_len, desc);
1595
1596                 if ((desc[0] != total_len) || /* descriptor length */
1597                     (desc[1] != 0x5f) ||   /* vendor descriptor type */
1598                     (desc[2] != 0x01) ||   /* version (2 bytes) */
1599                     (desc[3] != 0x00) ||
1600                     (desc[4] != total_len - 2)) /* length after type */
1601                         goto unrecognized;
1602
1603                 desc_end = desc + total_len;
1604                 desc += 5; /* the fixed header we've already parsed */
1605
1606                 while (desc < desc_end) {
1607                         u8 length;
1608                         u16 key;
1609
1610                         key = *desc++;
1611                         key |= (u16)*desc++ << 8;
1612                         length = *desc++;
1613
1614                         switch (key) {
1615                         case 0x0200: { /* max_area */
1616                                 u32 max_area = *desc++;
1617                                 max_area |= (u32)*desc++ << 8;
1618                                 max_area |= (u32)*desc++ << 16;
1619                                 max_area |= (u32)*desc++ << 24;
1620                                 dev_warn(&intf->dev,
1621                                          "DL chip limited to %d pixel modes\n",
1622                                          max_area);
1623                                 dlfb->sku_pixel_limit = max_area;
1624                                 break;
1625                         }
1626                         default:
1627                                 break;
1628                         }
1629                         desc += length;
1630                 }
1631         } else {
1632                 dev_info(&intf->dev, "vendor descriptor not available (%d)\n",
1633                          total_len);
1634         }
1635
1636         goto success;
1637
1638 unrecognized:
1639         /* allow udlfb to load for now even if firmware unrecognized */
1640         dev_err(&intf->dev, "Unrecognized vendor firmware descriptor\n");
1641
1642 success:
1643         kfree(buf);
1644         return true;
1645 }
1646
1647 static int dlfb_usb_probe(struct usb_interface *intf,
1648                           const struct usb_device_id *id)
1649 {
1650         int i;
1651         const struct device_attribute *attr;
1652         struct dlfb_data *dlfb;
1653         struct fb_info *info;
1654         int retval;
1655         struct usb_device *usbdev = interface_to_usbdev(intf);
1656         static u8 out_ep[] = {OUT_EP_NUM + USB_DIR_OUT, 0};
1657
1658         /* usb initialization */
1659         dlfb = kzalloc(sizeof(*dlfb), GFP_KERNEL);
1660         if (!dlfb) {
1661                 dev_err(&intf->dev, "%s: failed to allocate dlfb\n", __func__);
1662                 return -ENOMEM;
1663         }
1664
1665         INIT_LIST_HEAD(&dlfb->deferred_free);
1666
1667         dlfb->udev = usb_get_dev(usbdev);
1668         usb_set_intfdata(intf, dlfb);
1669
1670         if (!usb_check_bulk_endpoints(intf, out_ep)) {
1671                 dev_err(&intf->dev, "Invalid DisplayLink device!\n");
1672                 retval = -EINVAL;
1673                 goto error;
1674         }
1675
1676         dev_dbg(&intf->dev, "console enable=%d\n", console);
1677         dev_dbg(&intf->dev, "fb_defio enable=%d\n", fb_defio);
1678         dev_dbg(&intf->dev, "shadow enable=%d\n", shadow);
1679
1680         dlfb->sku_pixel_limit = 2048 * 1152; /* default to maximum */
1681
1682         if (!dlfb_parse_vendor_descriptor(dlfb, intf)) {
1683                 dev_err(&intf->dev,
1684                         "firmware not recognized, incompatible device?\n");
1685                 retval = -ENODEV;
1686                 goto error;
1687         }
1688
1689         if (pixel_limit) {
1690                 dev_warn(&intf->dev,
1691                          "DL chip limit of %d overridden to %d\n",
1692                          dlfb->sku_pixel_limit, pixel_limit);
1693                 dlfb->sku_pixel_limit = pixel_limit;
1694         }
1695
1696
1697         /* allocates framebuffer driver structure, not framebuffer memory */
1698         info = framebuffer_alloc(0, &dlfb->udev->dev);
1699         if (!info) {
1700                 retval = -ENOMEM;
1701                 goto error;
1702         }
1703
1704         dlfb->info = info;
1705         info->par = dlfb;
1706         info->pseudo_palette = dlfb->pseudo_palette;
1707         dlfb->ops = dlfb_ops;
1708         info->fbops = &dlfb->ops;
1709
1710         mutex_init(&dlfb->render_mutex);
1711         dlfb_init_damage(dlfb);
1712         spin_lock_init(&dlfb->damage_lock);
1713         INIT_WORK(&dlfb->damage_work, dlfb_damage_work);
1714
1715         INIT_LIST_HEAD(&info->modelist);
1716
1717         if (!dlfb_alloc_urb_list(dlfb, WRITES_IN_FLIGHT, MAX_TRANSFER)) {
1718                 retval = -ENOMEM;
1719                 dev_err(&intf->dev, "unable to allocate urb list\n");
1720                 goto error;
1721         }
1722
1723         /* We don't register a new USB class. Our client interface is dlfbev */
1724
1725         retval = fb_alloc_cmap(&info->cmap, 256, 0);
1726         if (retval < 0) {
1727                 dev_err(info->device, "cmap allocation failed: %d\n", retval);
1728                 goto error;
1729         }
1730
1731         retval = dlfb_setup_modes(dlfb, info, NULL, 0);
1732         if (retval != 0) {
1733                 dev_err(info->device,
1734                         "unable to find common mode for display and adapter\n");
1735                 goto error;
1736         }
1737
1738         /* ready to begin using device */
1739
1740         atomic_set(&dlfb->usb_active, 1);
1741         dlfb_select_std_channel(dlfb);
1742
1743         dlfb_ops_check_var(&info->var, info);
1744         retval = dlfb_ops_set_par(info);
1745         if (retval)
1746                 goto error;
1747
1748         retval = register_framebuffer(info);
1749         if (retval < 0) {
1750                 dev_err(info->device, "unable to register framebuffer: %d\n",
1751                         retval);
1752                 goto error;
1753         }
1754
1755         for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++) {
1756                 attr = &fb_device_attrs[i];
1757                 retval = device_create_file(info->dev, attr);
1758                 if (retval)
1759                         dev_warn(info->device,
1760                                  "failed to create '%s' attribute: %d\n",
1761                                  attr->attr.name, retval);
1762         }
1763
1764         retval = device_create_bin_file(info->dev, &edid_attr);
1765         if (retval)
1766                 dev_warn(info->device, "failed to create '%s' attribute: %d\n",
1767                          edid_attr.attr.name, retval);
1768
1769         dev_info(info->device,
1770                  "%s is DisplayLink USB device (%dx%d, %dK framebuffer memory)\n",
1771                  dev_name(info->dev), info->var.xres, info->var.yres,
1772                  ((dlfb->backing_buffer) ?
1773                  info->fix.smem_len * 2 : info->fix.smem_len) >> 10);
1774         return 0;
1775
1776 error:
1777         if (dlfb->info) {
1778                 dlfb_ops_destroy(dlfb->info);
1779         } else {
1780                 usb_put_dev(dlfb->udev);
1781                 kfree(dlfb);
1782         }
1783         return retval;
1784 }
1785
1786 static void dlfb_usb_disconnect(struct usb_interface *intf)
1787 {
1788         struct dlfb_data *dlfb;
1789         struct fb_info *info;
1790         int i;
1791
1792         dlfb = usb_get_intfdata(intf);
1793         info = dlfb->info;
1794
1795         dev_dbg(&intf->dev, "USB disconnect starting\n");
1796
1797         /* we virtualize until all fb clients release. Then we free */
1798         dlfb->virtualized = true;
1799
1800         /* When non-active we'll update virtual framebuffer, but no new urbs */
1801         atomic_set(&dlfb->usb_active, 0);
1802
1803         /* this function will wait for all in-flight urbs to complete */
1804         dlfb_free_urb_list(dlfb);
1805
1806         /* remove udlfb's sysfs interfaces */
1807         for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
1808                 device_remove_file(info->dev, &fb_device_attrs[i]);
1809         device_remove_bin_file(info->dev, &edid_attr);
1810
1811         unregister_framebuffer(info);
1812 }
1813
1814 static struct usb_driver dlfb_driver = {
1815         .name = "udlfb",
1816         .probe = dlfb_usb_probe,
1817         .disconnect = dlfb_usb_disconnect,
1818         .id_table = id_table,
1819 };
1820
1821 module_usb_driver(dlfb_driver);
1822
1823 static void dlfb_urb_completion(struct urb *urb)
1824 {
1825         struct urb_node *unode = urb->context;
1826         struct dlfb_data *dlfb = unode->dlfb;
1827         unsigned long flags;
1828
1829         switch (urb->status) {
1830         case 0:
1831                 /* success */
1832                 break;
1833         case -ECONNRESET:
1834         case -ENOENT:
1835         case -ESHUTDOWN:
1836                 /* sync/async unlink faults aren't errors */
1837                 break;
1838         default:
1839                 dev_err(&dlfb->udev->dev,
1840                         "%s - nonzero write bulk status received: %d\n",
1841                         __func__, urb->status);
1842                 atomic_set(&dlfb->lost_pixels, 1);
1843                 break;
1844         }
1845
1846         urb->transfer_buffer_length = dlfb->urbs.size; /* reset to actual */
1847
1848         spin_lock_irqsave(&dlfb->urbs.lock, flags);
1849         list_add_tail(&unode->entry, &dlfb->urbs.list);
1850         dlfb->urbs.available++;
1851         spin_unlock_irqrestore(&dlfb->urbs.lock, flags);
1852
1853         up(&dlfb->urbs.limit_sem);
1854 }
1855
1856 static void dlfb_free_urb_list(struct dlfb_data *dlfb)
1857 {
1858         int count = dlfb->urbs.count;
1859         struct list_head *node;
1860         struct urb_node *unode;
1861         struct urb *urb;
1862
1863         /* keep waiting and freeing, until we've got 'em all */
1864         while (count--) {
1865                 down(&dlfb->urbs.limit_sem);
1866
1867                 spin_lock_irq(&dlfb->urbs.lock);
1868
1869                 node = dlfb->urbs.list.next; /* have reserved one with sem */
1870                 list_del_init(node);
1871
1872                 spin_unlock_irq(&dlfb->urbs.lock);
1873
1874                 unode = list_entry(node, struct urb_node, entry);
1875                 urb = unode->urb;
1876
1877                 /* Free each separately allocated piece */
1878                 usb_free_coherent(urb->dev, dlfb->urbs.size,
1879                                   urb->transfer_buffer, urb->transfer_dma);
1880                 usb_free_urb(urb);
1881                 kfree(node);
1882         }
1883
1884         dlfb->urbs.count = 0;
1885 }
1886
1887 static int dlfb_alloc_urb_list(struct dlfb_data *dlfb, int count, size_t size)
1888 {
1889         struct urb *urb;
1890         struct urb_node *unode;
1891         char *buf;
1892         size_t wanted_size = count * size;
1893
1894         spin_lock_init(&dlfb->urbs.lock);
1895
1896 retry:
1897         dlfb->urbs.size = size;
1898         INIT_LIST_HEAD(&dlfb->urbs.list);
1899
1900         sema_init(&dlfb->urbs.limit_sem, 0);
1901         dlfb->urbs.count = 0;
1902         dlfb->urbs.available = 0;
1903
1904         while (dlfb->urbs.count * size < wanted_size) {
1905                 unode = kzalloc(sizeof(*unode), GFP_KERNEL);
1906                 if (!unode)
1907                         break;
1908                 unode->dlfb = dlfb;
1909
1910                 urb = usb_alloc_urb(0, GFP_KERNEL);
1911                 if (!urb) {
1912                         kfree(unode);
1913                         break;
1914                 }
1915                 unode->urb = urb;
1916
1917                 buf = usb_alloc_coherent(dlfb->udev, size, GFP_KERNEL,
1918                                          &urb->transfer_dma);
1919                 if (!buf) {
1920                         kfree(unode);
1921                         usb_free_urb(urb);
1922                         if (size > PAGE_SIZE) {
1923                                 size /= 2;
1924                                 dlfb_free_urb_list(dlfb);
1925                                 goto retry;
1926                         }
1927                         break;
1928                 }
1929
1930                 /* urb->transfer_buffer_length set to actual before submit */
1931                 usb_fill_bulk_urb(urb, dlfb->udev,
1932                         usb_sndbulkpipe(dlfb->udev, OUT_EP_NUM),
1933                         buf, size, dlfb_urb_completion, unode);
1934                 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
1935
1936                 list_add_tail(&unode->entry, &dlfb->urbs.list);
1937
1938                 up(&dlfb->urbs.limit_sem);
1939                 dlfb->urbs.count++;
1940                 dlfb->urbs.available++;
1941         }
1942
1943         return dlfb->urbs.count;
1944 }
1945
1946 static struct urb *dlfb_get_urb(struct dlfb_data *dlfb)
1947 {
1948         int ret;
1949         struct list_head *entry;
1950         struct urb_node *unode;
1951
1952         /* Wait for an in-flight buffer to complete and get re-queued */
1953         ret = down_timeout(&dlfb->urbs.limit_sem, GET_URB_TIMEOUT);
1954         if (ret) {
1955                 atomic_set(&dlfb->lost_pixels, 1);
1956                 dev_warn(&dlfb->udev->dev,
1957                          "wait for urb interrupted: %d available: %d\n",
1958                          ret, dlfb->urbs.available);
1959                 return NULL;
1960         }
1961
1962         spin_lock_irq(&dlfb->urbs.lock);
1963
1964         BUG_ON(list_empty(&dlfb->urbs.list)); /* reserved one with limit_sem */
1965         entry = dlfb->urbs.list.next;
1966         list_del_init(entry);
1967         dlfb->urbs.available--;
1968
1969         spin_unlock_irq(&dlfb->urbs.lock);
1970
1971         unode = list_entry(entry, struct urb_node, entry);
1972         return unode->urb;
1973 }
1974
1975 static int dlfb_submit_urb(struct dlfb_data *dlfb, struct urb *urb, size_t len)
1976 {
1977         int ret;
1978
1979         BUG_ON(len > dlfb->urbs.size);
1980
1981         urb->transfer_buffer_length = len; /* set to actual payload len */
1982         ret = usb_submit_urb(urb, GFP_KERNEL);
1983         if (ret) {
1984                 dlfb_urb_completion(urb); /* because no one else will */
1985                 atomic_set(&dlfb->lost_pixels, 1);
1986                 dev_err(&dlfb->udev->dev, "submit urb error: %d\n", ret);
1987         }
1988         return ret;
1989 }
1990
1991 module_param(console, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1992 MODULE_PARM_DESC(console, "Allow fbcon to open framebuffer");
1993
1994 module_param(fb_defio, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1995 MODULE_PARM_DESC(fb_defio, "Page fault detection of mmap writes");
1996
1997 module_param(shadow, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1998 MODULE_PARM_DESC(shadow, "Shadow vid mem. Disable to save mem but lose perf");
1999
2000 module_param(pixel_limit, int, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
2001 MODULE_PARM_DESC(pixel_limit, "Force limit on max mode (in x*y pixels)");
2002
2003 MODULE_AUTHOR("Roberto De Ioris <roberto@unbit.it>, "
2004               "Jaya Kumar <jayakumar.lkml@gmail.com>, "
2005               "Bernie Thompson <bernie@plugable.com>");
2006 MODULE_DESCRIPTION("DisplayLink kernel framebuffer driver");
2007 MODULE_LICENSE("GPL");
2008