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 <[email protected]>
   6  * Copyright (C) 2009 Jaya Kumar <[email protected]>
   7  * Copyright (C) 2009 Bernie Thompson <[email protected]>
   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 <linux/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_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         vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
 335
 336         if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
 337                 return -EINVAL;
 338         if (size > info->fix.smem_len)
 339                 return -EINVAL;
 340         if (offset > info->fix.smem_len - size)
 341                 return -EINVAL;
 342
 343         pos = (unsigned long)info->fix.smem_start + offset;
 344
 345         dev_dbg(info->dev, "mmap() framebuffer addr:%lu size:%lu\n",
 346                 pos, size);
 347
 348         while (size > 0) {
 349                 page = vmalloc_to_pfn((void *)pos);
 350                 if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
 351                         return -EAGAIN;
 352
 353                 start += PAGE_SIZE;
 354                 pos += PAGE_SIZE;
 355                 if (size > PAGE_SIZE)
 356                         size -= PAGE_SIZE;
 357                 else
 358                         size = 0;
 359         }
 360
 361         return 0;
 362 }
 363
 364 /*
 365  * Trims identical data from front and back of line
 366  * Sets new front buffer address and width
 367  * And returns byte count of identical pixels
 368  * Assumes CPU natural alignment (unsigned long)
 369  * for back and front buffer ptrs and width
 370  */
 371 static int dlfb_trim_hline(const u8 *bback, const u8 **bfront, int *width_bytes)
 372 {
 373         int j, k;
 374         const unsigned long *back = (const unsigned long *) bback;
 375         const unsigned long *front = (const unsigned long *) *bfront;
 376         const int width = *width_bytes / sizeof(unsigned long);
 377         int identical;
 378         int start = width;
 379         int end = width;
 380
 381         for (j = 0; j < width; j++) {
 382                 if (back[j] != front[j]) {
 383                         start = j;
 384                         break;
 385                 }
 386         }
 387
 388         for (k = width - 1; k > j; k--) {
 389                 if (back[k] != front[k]) {
 390                         end = k+1;
 391                         break;
 392                 }
 393         }
 394
 395         identical = start + (width - end);
 396         *bfront = (u8 *) &front[start];
 397         *width_bytes = (end - start) * sizeof(unsigned long);
 398
 399         return identical * sizeof(unsigned long);
 400 }
 401
 402 /*
 403  * Render a command stream for an encoded horizontal line segment of pixels.
 404  *
 405  * A command buffer holds several commands.
 406  * It always begins with a fresh command header
 407  * (the protocol doesn't require this, but we enforce it to allow
 408  * multiple buffers to be potentially encoded and sent in parallel).
 409  * A single command encodes one contiguous horizontal line of pixels
 410  *
 411  * The function relies on the client to do all allocation, so that
 412  * rendering can be done directly to output buffers (e.g. USB URBs).
 413  * The function fills the supplied command buffer, providing information
 414  * on where it left off, so the client may call in again with additional
 415  * buffers if the line will take several buffers to complete.
 416  *
 417  * A single command can transmit a maximum of 256 pixels,
 418  * regardless of the compression ratio (protocol design limit).
 419  * To the hardware, 0 for a size byte means 256
 420  *
 421  * Rather than 256 pixel commands which are either rl or raw encoded,
 422  * the rlx command simply assumes alternating raw and rl spans within one cmd.
 423  * This has a slightly larger header overhead, but produces more even results.
 424  * It also processes all data (read and write) in a single pass.
 425  * Performance benchmarks of common cases show it having just slightly better
 426  * compression than 256 pixel raw or rle commands, with similar CPU consumpion.
 427  * But for very rl friendly data, will compress not quite as well.
 428  */
 429 static void dlfb_compress_hline(
 430         const uint16_t **pixel_start_ptr,
 431         const uint16_t *const pixel_end,
 432         uint32_t *device_address_ptr,
 433         uint8_t **command_buffer_ptr,
 434         const uint8_t *const cmd_buffer_end,
 435         unsigned long back_buffer_offset,
 436         int *ident_ptr)
 437 {
 438         const uint16_t *pixel = *pixel_start_ptr;
 439         uint32_t dev_addr  = *device_address_ptr;
 440         uint8_t *cmd = *command_buffer_ptr;
 441
 442         while ((pixel_end > pixel) &&
 443                (cmd_buffer_end - MIN_RLX_CMD_BYTES > cmd)) {
 444                 uint8_t *raw_pixels_count_byte = NULL;
 445                 uint8_t *cmd_pixels_count_byte = NULL;
 446                 const uint16_t *raw_pixel_start = NULL;
 447                 const uint16_t *cmd_pixel_start, *cmd_pixel_end = NULL;
 448
 449                 if (back_buffer_offset &&
 450                     *pixel == *(u16 *)((u8 *)pixel + back_buffer_offset)) {
 451                         pixel++;
 452                         dev_addr += BPP;
 453                         (*ident_ptr)++;
 454                         continue;
 455                 }
 456
 457                 *cmd++ = 0xAF;
 458                 *cmd++ = 0x6B;
 459                 *cmd++ = dev_addr >> 16;
 460                 *cmd++ = dev_addr >> 8;
 461                 *cmd++ = dev_addr;
 462
 463                 cmd_pixels_count_byte = cmd++; /*  we'll know this later */
 464                 cmd_pixel_start = pixel;
 465
 466                 raw_pixels_count_byte = cmd++; /*  we'll know this later */
 467                 raw_pixel_start = pixel;
 468
 469                 cmd_pixel_end = pixel + min3(MAX_CMD_PIXELS + 1UL,
 470                                         (unsigned long)(pixel_end - pixel),
 471                                         (unsigned long)(cmd_buffer_end - 1 - cmd) / BPP);
 472
 473                 if (back_buffer_offset) {
 474                         /* note: the framebuffer may change under us, so we must test for underflow */
 475                         while (cmd_pixel_end - 1 > pixel &&
 476                                *(cmd_pixel_end - 1) == *(u16 *)((u8 *)(cmd_pixel_end - 1) + back_buffer_offset))
 477                                 cmd_pixel_end--;
 478                 }
 479
 480                 while (pixel < cmd_pixel_end) {
 481                         const uint16_t * const repeating_pixel = pixel;
 482                         u16 pixel_value = *pixel;
 483
 484                         put_unaligned_be16(pixel_value, cmd);
 485                         if (back_buffer_offset)
 486                                 *(u16 *)((u8 *)pixel + back_buffer_offset) = pixel_value;
 487                         cmd += 2;
 488                         pixel++;
 489
 490                         if (unlikely((pixel < cmd_pixel_end) &&
 491                                      (*pixel == pixel_value))) {
 492                                 /* go back and fill in raw pixel count */
 493                                 *raw_pixels_count_byte = ((repeating_pixel -
 494                                                 raw_pixel_start) + 1) & 0xFF;
 495
 496                                 do {
 497                                         if (back_buffer_offset)
 498                                                 *(u16 *)((u8 *)pixel + back_buffer_offset) = pixel_value;
 499                                         pixel++;
 500                                 } while ((pixel < cmd_pixel_end) &&
 501                                          (*pixel == pixel_value));
 502
 503                                 /* immediately after raw data is repeat byte */
 504                                 *cmd++ = ((pixel - repeating_pixel) - 1) & 0xFF;
 505
 506                                 /* Then start another raw pixel span */
 507                                 raw_pixel_start = pixel;
 508                                 raw_pixels_count_byte = cmd++;
 509                         }
 510                 }
 511
 512                 if (pixel > raw_pixel_start) {
 513                         /* finalize last RAW span */
 514                         *raw_pixels_count_byte = (pixel-raw_pixel_start) & 0xFF;
 515                 } else {
 516                         /* undo unused byte */
 517                         cmd--;
 518                 }
 519
 520                 *cmd_pixels_count_byte = (pixel - cmd_pixel_start) & 0xFF;
 521                 dev_addr += (u8 *)pixel - (u8 *)cmd_pixel_start;
 522         }
 523
 524         if (cmd_buffer_end - MIN_RLX_CMD_BYTES <= cmd) {
 525                 /* Fill leftover bytes with no-ops */
 526                 if (cmd_buffer_end > cmd)
 527                         memset(cmd, 0xAF, cmd_buffer_end - cmd);
 528                 cmd = (uint8_t *) cmd_buffer_end;
 529         }
 530
 531         *command_buffer_ptr = cmd;
 532         *pixel_start_ptr = pixel;
 533         *device_address_ptr = dev_addr;
 534 }
 535
 536 /*
 537  * There are 3 copies of every pixel: The front buffer that the fbdev
 538  * client renders to, the actual framebuffer across the USB bus in hardware
 539  * (that we can only write to, slowly, and can never read), and (optionally)
 540  * our shadow copy that tracks what's been sent to that hardware buffer.
 541  */
 542 static int dlfb_render_hline(struct dlfb_data *dlfb, struct urb **urb_ptr,
 543                               const char *front, char **urb_buf_ptr,
 544                               u32 byte_offset, u32 byte_width,
 545                               int *ident_ptr, int *sent_ptr)
 546 {
 547         const u8 *line_start, *line_end, *next_pixel;
 548         u32 dev_addr = dlfb->base16 + byte_offset;
 549         struct urb *urb = *urb_ptr;
 550         u8 *cmd = *urb_buf_ptr;
 551         u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
 552         unsigned long back_buffer_offset = 0;
 553
 554         line_start = (u8 *) (front + byte_offset);
 555         next_pixel = line_start;
 556         line_end = next_pixel + byte_width;
 557
 558         if (dlfb->backing_buffer) {
 559                 int offset;
 560                 const u8 *back_start = (u8 *) (dlfb->backing_buffer
 561                                                 + byte_offset);
 562
 563                 back_buffer_offset = (unsigned long)back_start - (unsigned long)line_start;
 564
 565                 *ident_ptr += dlfb_trim_hline(back_start, &next_pixel,
 566                         &byte_width);
 567
 568                 offset = next_pixel - line_start;
 569                 line_end = next_pixel + byte_width;
 570                 dev_addr += offset;
 571                 back_start += offset;
 572                 line_start += offset;
 573         }
 574
 575         while (next_pixel < line_end) {
 576
 577                 dlfb_compress_hline((const uint16_t **) &next_pixel,
 578                              (const uint16_t *) line_end, &dev_addr,
 579                         (u8 **) &cmd, (u8 *) cmd_end, back_buffer_offset,
 580                         ident_ptr);
 581
 582                 if (cmd >= cmd_end) {
 583                         int len = cmd - (u8 *) urb->transfer_buffer;
 584                         if (dlfb_submit_urb(dlfb, urb, len))
 585                                 return 1; /* lost pixels is set */
 586                         *sent_ptr += len;
 587                         urb = dlfb_get_urb(dlfb);
 588                         if (!urb)
 589                                 return 1; /* lost_pixels is set */
 590                         *urb_ptr = urb;
 591                         cmd = urb->transfer_buffer;
 592                         cmd_end = &cmd[urb->transfer_buffer_length];
 593                 }
 594         }
 595
 596         *urb_buf_ptr = cmd;
 597
 598         return 0;
 599 }
 600
 601 static int dlfb_handle_damage(struct dlfb_data *dlfb, int x, int y, int width, int height)
 602 {
 603         int i, ret;
 604         char *cmd;
 605         cycles_t start_cycles, end_cycles;
 606         int bytes_sent = 0;
 607         int bytes_identical = 0;
 608         struct urb *urb;
 609         int aligned_x;
 610
 611         start_cycles = get_cycles();
 612
 613         mutex_lock(&dlfb->render_mutex);
 614
 615         aligned_x = DL_ALIGN_DOWN(x, sizeof(unsigned long));
 616         width = DL_ALIGN_UP(width + (x-aligned_x), sizeof(unsigned long));
 617         x = aligned_x;
 618
 619         if ((width <= 0) ||
 620             (x + width > dlfb->info->var.xres) ||
 621             (y + height > dlfb->info->var.yres)) {
 622                 ret = -EINVAL;
 623                 goto unlock_ret;
 624         }
 625
 626         if (!atomic_read(&dlfb->usb_active)) {
 627                 ret = 0;
 628                 goto unlock_ret;
 629         }
 630
 631         urb = dlfb_get_urb(dlfb);
 632         if (!urb) {
 633                 ret = 0;
 634                 goto unlock_ret;
 635         }
 636         cmd = urb->transfer_buffer;
 637
 638         for (i = y; i < y + height ; i++) {
 639                 const int line_offset = dlfb->info->fix.line_length * i;
 640                 const int byte_offset = line_offset + (x * BPP);
 641
 642                 if (dlfb_render_hline(dlfb, &urb,
 643                                       (char *) dlfb->info->fix.smem_start,
 644                                       &cmd, byte_offset, width * BPP,
 645                                       &bytes_identical, &bytes_sent))
 646                         goto error;
 647         }
 648
 649         if (cmd > (char *) urb->transfer_buffer) {
 650                 int len;
 651                 if (cmd < (char *) urb->transfer_buffer + urb->transfer_buffer_length)
 652                         *cmd++ = 0xAF;
 653                 /* Send partial buffer remaining before exiting */
 654                 len = cmd - (char *) urb->transfer_buffer;
 655                 dlfb_submit_urb(dlfb, urb, len);
 656                 bytes_sent += len;
 657         } else
 658                 dlfb_urb_completion(urb);
 659
 660 error:
 661         atomic_add(bytes_sent, &dlfb->bytes_sent);
 662         atomic_add(bytes_identical, &dlfb->bytes_identical);
 663         atomic_add(width*height*2, &dlfb->bytes_rendered);
 664         end_cycles = get_cycles();
 665         atomic_add(((unsigned int) ((end_cycles - start_cycles)
 666                     >> 10)), /* Kcycles */
 667                    &dlfb->cpu_kcycles_used);
 668
 669         ret = 0;
 670
 671 unlock_ret:
 672         mutex_unlock(&dlfb->render_mutex);
 673         return ret;
 674 }
 675
 676 static void dlfb_init_damage(struct dlfb_data *dlfb)
 677 {
 678         dlfb->damage_x = INT_MAX;
 679         dlfb->damage_x2 = 0;
 680         dlfb->damage_y = INT_MAX;
 681         dlfb->damage_y2 = 0;
 682 }
 683
 684 static void dlfb_damage_work(struct work_struct *w)
 685 {
 686         struct dlfb_data *dlfb = container_of(w, struct dlfb_data, damage_work);
 687         int x, x2, y, y2;
 688
 689         spin_lock_irq(&dlfb->damage_lock);
 690         x = dlfb->damage_x;
 691         x2 = dlfb->damage_x2;
 692         y = dlfb->damage_y;
 693         y2 = dlfb->damage_y2;
 694         dlfb_init_damage(dlfb);
 695         spin_unlock_irq(&dlfb->damage_lock);
 696
 697         if (x < x2 && y < y2)
 698                 dlfb_handle_damage(dlfb, x, y, x2 - x, y2 - y);
 699 }
 700
 701 static void dlfb_offload_damage(struct dlfb_data *dlfb, int x, int y, int width, int height)
 702 {
 703         unsigned long flags;
 704         int x2 = x + width;
 705         int y2 = y + height;
 706
 707         if (x >= x2 || y >= y2)
 708                 return;
 709
 710         spin_lock_irqsave(&dlfb->damage_lock, flags);
 711         dlfb->damage_x = min(x, dlfb->damage_x);
 712         dlfb->damage_x2 = max(x2, dlfb->damage_x2);
 713         dlfb->damage_y = min(y, dlfb->damage_y);
 714         dlfb->damage_y2 = max(y2, dlfb->damage_y2);
 715         spin_unlock_irqrestore(&dlfb->damage_lock, flags);
 716
 717         schedule_work(&dlfb->damage_work);
 718 }
 719
 720 /*
 721  * NOTE: fb_defio.c is holding info->fbdefio.mutex
 722  *   Touching ANY framebuffer memory that triggers a page fault
 723  *   in fb_defio will cause a deadlock, when it also tries to
 724  *   grab the same mutex.
 725  */
 726 static void dlfb_dpy_deferred_io(struct fb_info *info, struct list_head *pagereflist)
 727 {
 728         struct fb_deferred_io_pageref *pageref;
 729         struct dlfb_data *dlfb = info->par;
 730         struct urb *urb;
 731         char *cmd;
 732         cycles_t start_cycles, end_cycles;
 733         int bytes_sent = 0;
 734         int bytes_identical = 0;
 735         int bytes_rendered = 0;
 736
 737         mutex_lock(&dlfb->render_mutex);
 738
 739         if (!fb_defio)
 740                 goto unlock_ret;
 741
 742         if (!atomic_read(&dlfb->usb_active))
 743                 goto unlock_ret;
 744
 745         start_cycles = get_cycles();
 746
 747         urb = dlfb_get_urb(dlfb);
 748         if (!urb)
 749                 goto unlock_ret;
 750
 751         cmd = urb->transfer_buffer;
 752
 753         /* walk the written page list and render each to device */
 754         list_for_each_entry(pageref, pagereflist, list) {
 755                 if (dlfb_render_hline(dlfb, &urb, (char *) info->fix.smem_start,
 756                                       &cmd, pageref->offset, PAGE_SIZE,
 757                                       &bytes_identical, &bytes_sent))
 758                         goto error;
 759                 bytes_rendered += PAGE_SIZE;
 760         }
 761
 762         if (cmd > (char *) urb->transfer_buffer) {
 763                 int len;
 764                 if (cmd < (char *) urb->transfer_buffer + urb->transfer_buffer_length)
 765                         *cmd++ = 0xAF;
 766                 /* Send partial buffer remaining before exiting */
 767                 len = cmd - (char *) urb->transfer_buffer;
 768                 dlfb_submit_urb(dlfb, urb, len);
 769                 bytes_sent += len;
 770         } else
 771                 dlfb_urb_completion(urb);
 772
 773 error:
 774         atomic_add(bytes_sent, &dlfb->bytes_sent);
 775         atomic_add(bytes_identical, &dlfb->bytes_identical);
 776         atomic_add(bytes_rendered, &dlfb->bytes_rendered);
 777         end_cycles = get_cycles();
 778         atomic_add(((unsigned int) ((end_cycles - start_cycles)
 779                     >> 10)), /* Kcycles */
 780                    &dlfb->cpu_kcycles_used);
 781 unlock_ret:
 782         mutex_unlock(&dlfb->render_mutex);
 783 }
 784
 785 static int dlfb_get_edid(struct dlfb_data *dlfb, char *edid, int len)
 786 {
 787         int i, ret;
 788         char *rbuf;
 789
 790         rbuf = kmalloc(2, GFP_KERNEL);
 791         if (!rbuf)
 792                 return 0;
 793
 794         for (i = 0; i < len; i++) {
 795                 ret = usb_control_msg(dlfb->udev,
 796                                       usb_rcvctrlpipe(dlfb->udev, 0), 0x02,
 797                                       (0x80 | (0x02 << 5)), i << 8, 0xA1,
 798                                       rbuf, 2, USB_CTRL_GET_TIMEOUT);
 799                 if (ret < 2) {
 800                         dev_err(&dlfb->udev->dev,
 801                                 "Read EDID byte %d failed: %d\n", i, ret);
 802                         i--;
 803                         break;
 804                 }
 805                 edid[i] = rbuf[1];
 806         }
 807
 808         kfree(rbuf);
 809
 810         return i;
 811 }
 812
 813 static int dlfb_ops_ioctl(struct fb_info *info, unsigned int cmd,
 814                                 unsigned long arg)
 815 {
 816
 817         struct dlfb_data *dlfb = info->par;
 818
 819         if (!atomic_read(&dlfb->usb_active))
 820                 return 0;
 821
 822         /* TODO: Update X server to get this from sysfs instead */
 823         if (cmd == DLFB_IOCTL_RETURN_EDID) {
 824                 void __user *edid = (void __user *)arg;
 825                 if (copy_to_user(edid, dlfb->edid, dlfb->edid_size))
 826                         return -EFAULT;
 827                 return 0;
 828         }
 829
 830         /* TODO: Help propose a standard fb.h ioctl to report mmap damage */
 831         if (cmd == DLFB_IOCTL_REPORT_DAMAGE) {
 832                 struct dloarea area;
 833
 834                 if (copy_from_user(&area, (void __user *)arg,
 835                                   sizeof(struct dloarea)))
 836                         return -EFAULT;
 837
 838                 /*
 839                  * If we have a damage-aware client, turn fb_defio "off"
 840                  * To avoid perf imact of unnecessary page fault handling.
 841                  * Done by resetting the delay for this fb_info to a very
 842                  * long period. Pages will become writable and stay that way.
 843                  * Reset to normal value when all clients have closed this fb.
 844                  */
 845                 if (info->fbdefio)
 846                         info->fbdefio->delay = DL_DEFIO_WRITE_DISABLE;
 847
 848                 if (area.x < 0)
 849                         area.x = 0;
 850
 851                 if (area.x > info->var.xres)
 852                         area.x = info->var.xres;
 853
 854                 if (area.y < 0)
 855                         area.y = 0;
 856
 857                 if (area.y > info->var.yres)
 858                         area.y = info->var.yres;
 859
 860                 dlfb_handle_damage(dlfb, area.x, area.y, area.w, area.h);
 861         }
 862
 863         return 0;
 864 }
 865
 866 /* taken from vesafb */
 867 static int
 868 dlfb_ops_setcolreg(unsigned regno, unsigned red, unsigned green,
 869                unsigned blue, unsigned transp, struct fb_info *info)
 870 {
 871         int err = 0;
 872
 873         if (regno >= info->cmap.len)
 874                 return 1;
 875
 876         if (regno < 16) {
 877                 if (info->var.red.offset == 10) {
 878                         /* 1:5:5:5 */
 879                         ((u32 *) (info->pseudo_palette))[regno] =
 880                             ((red & 0xf800) >> 1) |
 881                             ((green & 0xf800) >> 6) | ((blue & 0xf800) >> 11);
 882                 } else {
 883                         /* 0:5:6:5 */
 884                         ((u32 *) (info->pseudo_palette))[regno] =
 885                             ((red & 0xf800)) |
 886                             ((green & 0xfc00) >> 5) | ((blue & 0xf800) >> 11);
 887                 }
 888         }
 889
 890         return err;
 891 }
 892
 893 /*
 894  * It's common for several clients to have framebuffer open simultaneously.
 895  * e.g. both fbcon and X. Makes things interesting.
 896  * Assumes caller is holding info->lock (for open and release at least)
 897  */
 898 static int dlfb_ops_open(struct fb_info *info, int user)
 899 {
 900         struct dlfb_data *dlfb = info->par;
 901
 902         /*
 903          * fbcon aggressively connects to first framebuffer it finds,
 904          * preventing other clients (X) from working properly. Usually
 905          * not what the user wants. Fail by default with option to enable.
 906          */
 907         if ((user == 0) && (!console))
 908                 return -EBUSY;
 909
 910         /* If the USB device is gone, we don't accept new opens */
 911         if (dlfb->virtualized)
 912                 return -ENODEV;
 913
 914         dlfb->fb_count++;
 915
 916         if (fb_defio && (info->fbdefio == NULL)) {
 917                 /* enable defio at last moment if not disabled by client */
 918
 919                 struct fb_deferred_io *fbdefio;
 920
 921                 fbdefio = kzalloc(sizeof(struct fb_deferred_io), GFP_KERNEL);
 922
 923                 if (fbdefio) {
 924                         fbdefio->delay = DL_DEFIO_WRITE_DELAY;
 925                         fbdefio->sort_pagereflist = true;
 926                         fbdefio->deferred_io = dlfb_dpy_deferred_io;
 927                 }
 928
 929                 info->fbdefio = fbdefio;
 930                 fb_deferred_io_init(info);
 931         }
 932
 933         dev_dbg(info->dev, "open, user=%d fb_info=%p count=%d\n",
 934                 user, info, dlfb->fb_count);
 935
 936         return 0;
 937 }
 938
 939 static void dlfb_ops_destroy(struct fb_info *info)
 940 {
 941         struct dlfb_data *dlfb = info->par;
 942
 943         cancel_work_sync(&dlfb->damage_work);
 944
 945         mutex_destroy(&dlfb->render_mutex);
 946
 947         if (info->cmap.len != 0)
 948                 fb_dealloc_cmap(&info->cmap);
 949         if (info->monspecs.modedb)
 950                 fb_destroy_modedb(info->monspecs.modedb);
 951         vfree(info->screen_buffer);
 952
 953         fb_destroy_modelist(&info->modelist);
 954
 955         while (!list_empty(&dlfb->deferred_free)) {
 956                 struct dlfb_deferred_free *d = list_entry(dlfb->deferred_free.next, struct dlfb_deferred_free, list);
 957                 list_del(&d->list);
 958                 vfree(d->mem);
 959                 kfree(d);
 960         }
 961         vfree(dlfb->backing_buffer);
 962         kfree(dlfb->edid);
 963         dlfb_free_urb_list(dlfb);
 964         usb_put_dev(dlfb->udev);
 965         kfree(dlfb);
 966
 967         /* Assume info structure is freed after this point */
 968         framebuffer_release(info);
 969 }
 970
 971 /*
 972  * Assumes caller is holding info->lock mutex (for open and release at least)
 973  */
 974 static int dlfb_ops_release(struct fb_info *info, int user)
 975 {
 976         struct dlfb_data *dlfb = info->par;
 977
 978         dlfb->fb_count--;
 979
 980         if ((dlfb->fb_count == 0) && (info->fbdefio)) {
 981                 fb_deferred_io_cleanup(info);
 982                 kfree(info->fbdefio);
 983                 info->fbdefio = NULL;
 984         }
 985
 986         dev_dbg(info->dev, "release, user=%d count=%d\n", user, dlfb->fb_count);
 987
 988         return 0;
 989 }
 990
 991 /*
 992  * Check whether a video mode is supported by the DisplayLink chip
 993  * We start from monitor's modes, so don't need to filter that here
 994  */
 995 static int dlfb_is_valid_mode(struct fb_videomode *mode, struct dlfb_data *dlfb)
 996 {
 997         if (mode->xres * mode->yres > dlfb->sku_pixel_limit)
 998                 return 0;
 999
1000         return 1;
1001 }
1002
1003 static void dlfb_var_color_format(struct fb_var_screeninfo *var)
1004 {
1005         const struct fb_bitfield red = { 11, 5, 0 };
1006         const struct fb_bitfield green = { 5, 6, 0 };
1007         const struct fb_bitfield blue = { 0, 5, 0 };
1008
1009         var->bits_per_pixel = 16;
1010         var->red = red;
1011         var->green = green;
1012         var->blue = blue;
1013 }
1014
1015 static int dlfb_ops_check_var(struct fb_var_screeninfo *var,
1016                                 struct fb_info *info)
1017 {
1018         struct fb_videomode mode;
1019         struct dlfb_data *dlfb = info->par;
1020
1021         /* set device-specific elements of var unrelated to mode */
1022         dlfb_var_color_format(var);
1023
1024         fb_var_to_videomode(&mode, var);
1025
1026         if (!dlfb_is_valid_mode(&mode, dlfb))
1027                 return -EINVAL;
1028
1029         return 0;
1030 }
1031
1032 static int dlfb_ops_set_par(struct fb_info *info)
1033 {
1034         struct dlfb_data *dlfb = info->par;
1035         int result;
1036         u16 *pix_framebuffer;
1037         int i;
1038         struct fb_var_screeninfo fvs;
1039         u32 line_length = info->var.xres * (info->var.bits_per_pixel / 8);
1040
1041         /* clear the activate field because it causes spurious miscompares */
1042         fvs = info->var;
1043         fvs.activate = 0;
1044         fvs.vmode &= ~FB_VMODE_SMOOTH_XPAN;
1045
1046         if (!memcmp(&dlfb->current_mode, &fvs, sizeof(struct fb_var_screeninfo)))
1047                 return 0;
1048
1049         result = dlfb_realloc_framebuffer(dlfb, info, info->var.yres * line_length);
1050         if (result)
1051                 return result;
1052
1053         result = dlfb_set_video_mode(dlfb, &info->var);
1054
1055         if (result)
1056                 return result;
1057
1058         dlfb->current_mode = fvs;
1059         info->fix.line_length = line_length;
1060
1061         if (dlfb->fb_count == 0) {
1062
1063                 /* paint greenscreen */
1064
1065                 pix_framebuffer = (u16 *)info->screen_buffer;
1066                 for (i = 0; i < info->fix.smem_len / 2; i++)
1067                         pix_framebuffer[i] = 0x37e6;
1068         }
1069
1070         dlfb_handle_damage(dlfb, 0, 0, info->var.xres, info->var.yres);
1071
1072         return 0;
1073 }
1074
1075 /* To fonzi the jukebox (e.g. make blanking changes take effect) */
1076 static char *dlfb_dummy_render(char *buf)
1077 {
1078         *buf++ = 0xAF;
1079         *buf++ = 0x6A; /* copy */
1080         *buf++ = 0x00; /* from address*/
1081         *buf++ = 0x00;
1082         *buf++ = 0x00;
1083         *buf++ = 0x01; /* one pixel */
1084         *buf++ = 0x00; /* to address */
1085         *buf++ = 0x00;
1086         *buf++ = 0x00;
1087         return buf;
1088 }
1089
1090 /*
1091  * In order to come back from full DPMS off, we need to set the mode again
1092  */
1093 static int dlfb_ops_blank(int blank_mode, struct fb_info *info)
1094 {
1095         struct dlfb_data *dlfb = info->par;
1096         char *bufptr;
1097         struct urb *urb;
1098
1099         dev_dbg(info->dev, "blank, mode %d --> %d\n",
1100                 dlfb->blank_mode, blank_mode);
1101
1102         if ((dlfb->blank_mode == FB_BLANK_POWERDOWN) &&
1103             (blank_mode != FB_BLANK_POWERDOWN)) {
1104
1105                 /* returning from powerdown requires a fresh modeset */
1106                 dlfb_set_video_mode(dlfb, &info->var);
1107         }
1108
1109         urb = dlfb_get_urb(dlfb);
1110         if (!urb)
1111                 return 0;
1112
1113         bufptr = (char *) urb->transfer_buffer;
1114         bufptr = dlfb_vidreg_lock(bufptr);
1115         bufptr = dlfb_blanking(bufptr, blank_mode);
1116         bufptr = dlfb_vidreg_unlock(bufptr);
1117
1118         /* seems like a render op is needed to have blank change take effect */
1119         bufptr = dlfb_dummy_render(bufptr);
1120
1121         dlfb_submit_urb(dlfb, urb, bufptr -
1122                         (char *) urb->transfer_buffer);
1123
1124         dlfb->blank_mode = blank_mode;
1125
1126         return 0;
1127 }
1128
1129 static void dlfb_ops_damage_range(struct fb_info *info, off_t off, size_t len)
1130 {
1131         struct dlfb_data *dlfb = info->par;
1132         int start = max((int)(off / info->fix.line_length), 0);
1133         int lines = min((u32)((len / info->fix.line_length) + 1), (u32)info->var.yres);
1134
1135         dlfb_handle_damage(dlfb, 0, start, info->var.xres, lines);
1136 }
1137
1138 static void dlfb_ops_damage_area(struct fb_info *info, u32 x, u32 y, u32 width, u32 height)
1139 {
1140         struct dlfb_data *dlfb = info->par;
1141
1142         dlfb_offload_damage(dlfb, x, y, width, height);
1143 }
1144
1145 FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(dlfb_ops,
1146                                    dlfb_ops_damage_range,
1147                                    dlfb_ops_damage_area)
1148
1149 static const struct fb_ops dlfb_ops = {
1150         .owner = THIS_MODULE,
1151         __FB_DEFAULT_DEFERRED_OPS_RDWR(dlfb_ops),
1152         .fb_setcolreg = dlfb_ops_setcolreg,
1153         __FB_DEFAULT_DEFERRED_OPS_DRAW(dlfb_ops),
1154         .fb_mmap = dlfb_ops_mmap,
1155         .fb_ioctl = dlfb_ops_ioctl,
1156         .fb_open = dlfb_ops_open,
1157         .fb_release = dlfb_ops_release,
1158         .fb_blank = dlfb_ops_blank,
1159         .fb_check_var = dlfb_ops_check_var,
1160         .fb_set_par = dlfb_ops_set_par,
1161         .fb_destroy = dlfb_ops_destroy,
1162 };
1163
1164
1165 static void dlfb_deferred_vfree(struct dlfb_data *dlfb, void *mem)
1166 {
1167         struct dlfb_deferred_free *d = kmalloc(sizeof(struct dlfb_deferred_free), GFP_KERNEL);
1168         if (!d)
1169                 return;
1170         d->mem = mem;
1171         list_add(&d->list, &dlfb->deferred_free);
1172 }
1173
1174 /*
1175  * Assumes &info->lock held by caller
1176  * Assumes no active clients have framebuffer open
1177  */
1178 static int dlfb_realloc_framebuffer(struct dlfb_data *dlfb, struct fb_info *info, u32 new_len)
1179 {
1180         u32 old_len = info->fix.smem_len;
1181         const void *old_fb = info->screen_buffer;
1182         unsigned char *new_fb;
1183         unsigned char *new_back = NULL;
1184
1185         new_len = PAGE_ALIGN(new_len);
1186
1187         if (new_len > old_len) {
1188                 /*
1189                  * Alloc system memory for virtual framebuffer
1190                  */
1191                 new_fb = vmalloc(new_len);
1192                 if (!new_fb) {
1193                         dev_err(info->dev, "Virtual framebuffer alloc failed\n");
1194                         return -ENOMEM;
1195                 }
1196                 memset(new_fb, 0xff, new_len);
1197
1198                 if (info->screen_buffer) {
1199                         memcpy(new_fb, old_fb, old_len);
1200                         dlfb_deferred_vfree(dlfb, info->screen_buffer);
1201                 }
1202
1203                 info->screen_buffer = new_fb;
1204                 info->fix.smem_len = new_len;
1205                 info->fix.smem_start = (unsigned long) new_fb;
1206                 info->flags = udlfb_info_flags;
1207
1208                 /*
1209                  * Second framebuffer copy to mirror the framebuffer state
1210                  * on the physical USB device. We can function without this.
1211                  * But with imperfect damage info we may send pixels over USB
1212                  * that were, in fact, unchanged - wasting limited USB bandwidth
1213                  */
1214                 if (shadow)
1215                         new_back = vzalloc(new_len);
1216                 if (!new_back)
1217                         dev_info(info->dev,
1218                                  "No shadow/backing buffer allocated\n");
1219                 else {
1220                         dlfb_deferred_vfree(dlfb, dlfb->backing_buffer);
1221                         dlfb->backing_buffer = new_back;
1222                 }
1223         }
1224         return 0;
1225 }
1226
1227 /*
1228  * 1) Get EDID from hw, or use sw default
1229  * 2) Parse into various fb_info structs
1230  * 3) Allocate virtual framebuffer memory to back highest res mode
1231  *
1232  * Parses EDID into three places used by various parts of fbdev:
1233  * fb_var_screeninfo contains the timing of the monitor's preferred mode
1234  * fb_info.monspecs is full parsed EDID info, including monspecs.modedb
1235  * fb_info.modelist is a linked list of all monitor & VESA modes which work
1236  *
1237  * If EDID is not readable/valid, then modelist is all VESA modes,
1238  * monspecs is NULL, and fb_var_screeninfo is set to safe VESA mode
1239  * Returns 0 if successful
1240  */
1241 static int dlfb_setup_modes(struct dlfb_data *dlfb,
1242                            struct fb_info *info,
1243                            char *default_edid, size_t default_edid_size)
1244 {
1245         char *edid;
1246         int i, result = 0, tries = 3;
1247         struct device *dev = info->device;
1248         struct fb_videomode *mode;
1249         const struct fb_videomode *default_vmode = NULL;
1250
1251         if (info->dev) {
1252                 /* only use mutex if info has been registered */
1253                 mutex_lock(&info->lock);
1254                 /* parent device is used otherwise */
1255                 dev = info->dev;
1256         }
1257
1258         edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
1259         if (!edid) {
1260                 result = -ENOMEM;
1261                 goto error;
1262         }
1263
1264         fb_destroy_modelist(&info->modelist);
1265         memset(&info->monspecs, 0, sizeof(info->monspecs));
1266
1267         /*
1268          * Try to (re)read EDID from hardware first
1269          * EDID data may return, but not parse as valid
1270          * Try again a few times, in case of e.g. analog cable noise
1271          */
1272         while (tries--) {
1273
1274                 i = dlfb_get_edid(dlfb, edid, EDID_LENGTH);
1275
1276                 if (i >= EDID_LENGTH)
1277                         fb_edid_to_monspecs(edid, &info->monspecs);
1278
1279                 if (info->monspecs.modedb_len > 0) {
1280                         dlfb->edid = edid;
1281                         dlfb->edid_size = i;
1282                         break;
1283                 }
1284         }
1285
1286         /* If that fails, use a previously returned EDID if available */
1287         if (info->monspecs.modedb_len == 0) {
1288                 dev_err(dev, "Unable to get valid EDID from device/display\n");
1289
1290                 if (dlfb->edid) {
1291                         fb_edid_to_monspecs(dlfb->edid, &info->monspecs);
1292                         if (info->monspecs.modedb_len > 0)
1293                                 dev_err(dev, "Using previously queried EDID\n");
1294                 }
1295         }
1296
1297         /* If that fails, use the default EDID we were handed */
1298         if (info->monspecs.modedb_len == 0) {
1299                 if (default_edid_size >= EDID_LENGTH) {
1300                         fb_edid_to_monspecs(default_edid, &info->monspecs);
1301                         if (info->monspecs.modedb_len > 0) {
1302                                 memcpy(edid, default_edid, default_edid_size);
1303                                 dlfb->edid = edid;
1304                                 dlfb->edid_size = default_edid_size;
1305                                 dev_err(dev, "Using default/backup EDID\n");
1306                         }
1307                 }
1308         }
1309
1310         /* If we've got modes, let's pick a best default mode */
1311         if (info->monspecs.modedb_len > 0) {
1312
1313                 for (i = 0; i < info->monspecs.modedb_len; i++) {
1314                         mode = &info->monspecs.modedb[i];
1315                         if (dlfb_is_valid_mode(mode, dlfb)) {
1316                                 fb_add_videomode(mode, &info->modelist);
1317                         } else {
1318                                 dev_dbg(dev, "Specified mode %dx%d too big\n",
1319                                         mode->xres, mode->yres);
1320                                 if (i == 0)
1321                                         /* if we've removed top/best mode */
1322                                         info->monspecs.misc
1323                                                 &= ~FB_MISC_1ST_DETAIL;
1324                         }
1325                 }
1326
1327                 default_vmode = fb_find_best_display(&info->monspecs,
1328                                                      &info->modelist);
1329         }
1330
1331         /* If everything else has failed, fall back to safe default mode */
1332         if (default_vmode == NULL) {
1333
1334                 struct fb_videomode fb_vmode = {0};
1335
1336                 /*
1337                  * Add the standard VESA modes to our modelist
1338                  * Since we don't have EDID, there may be modes that
1339                  * overspec monitor and/or are incorrect aspect ratio, etc.
1340                  * But at least the user has a chance to choose
1341                  */
1342                 for (i = 0; i < VESA_MODEDB_SIZE; i++) {
1343                         mode = (struct fb_videomode *)&vesa_modes[i];
1344                         if (dlfb_is_valid_mode(mode, dlfb))
1345                                 fb_add_videomode(mode, &info->modelist);
1346                         else
1347                                 dev_dbg(dev, "VESA mode %dx%d too big\n",
1348                                         mode->xres, mode->yres);
1349                 }
1350
1351                 /*
1352                  * default to resolution safe for projectors
1353                  * (since they are most common case without EDID)
1354                  */
1355                 fb_vmode.xres = 800;
1356                 fb_vmode.yres = 600;
1357                 fb_vmode.refresh = 60;
1358                 default_vmode = fb_find_nearest_mode(&fb_vmode,
1359                                                      &info->modelist);
1360         }
1361
1362         /* If we have good mode and no active clients*/
1363         if ((default_vmode != NULL) && (dlfb->fb_count == 0)) {
1364
1365                 fb_videomode_to_var(&info->var, default_vmode);
1366                 dlfb_var_color_format(&info->var);
1367
1368                 /*
1369                  * with mode size info, we can now alloc our framebuffer.
1370                  */
1371                 memcpy(&info->fix, &dlfb_fix, sizeof(dlfb_fix));
1372         } else
1373                 result = -EINVAL;
1374
1375 error:
1376         if (edid && (dlfb->edid != edid))
1377                 kfree(edid);
1378
1379         if (info->dev)
1380                 mutex_unlock(&info->lock);
1381
1382         return result;
1383 }
1384
1385 static ssize_t metrics_bytes_rendered_show(struct device *fbdev,
1386                                    struct device_attribute *a, char *buf) {
1387         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1388         struct dlfb_data *dlfb = fb_info->par;
1389         return sysfs_emit(buf, "%u\n",
1390                         atomic_read(&dlfb->bytes_rendered));
1391 }
1392
1393 static ssize_t metrics_bytes_identical_show(struct device *fbdev,
1394                                    struct device_attribute *a, char *buf) {
1395         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1396         struct dlfb_data *dlfb = fb_info->par;
1397         return sysfs_emit(buf, "%u\n",
1398                         atomic_read(&dlfb->bytes_identical));
1399 }
1400
1401 static ssize_t metrics_bytes_sent_show(struct device *fbdev,
1402                                    struct device_attribute *a, char *buf) {
1403         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1404         struct dlfb_data *dlfb = fb_info->par;
1405         return sysfs_emit(buf, "%u\n",
1406                         atomic_read(&dlfb->bytes_sent));
1407 }
1408
1409 static ssize_t metrics_cpu_kcycles_used_show(struct device *fbdev,
1410                                    struct device_attribute *a, char *buf) {
1411         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1412         struct dlfb_data *dlfb = fb_info->par;
1413         return sysfs_emit(buf, "%u\n",
1414                         atomic_read(&dlfb->cpu_kcycles_used));
1415 }
1416
1417 static ssize_t edid_show(
1418                         struct file *filp,
1419                         struct kobject *kobj, const struct bin_attribute *a,
1420                          char *buf, loff_t off, size_t count) {
1421         struct device *fbdev = kobj_to_dev(kobj);
1422         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1423         struct dlfb_data *dlfb = fb_info->par;
1424
1425         if (dlfb->edid == NULL)
1426                 return 0;
1427
1428         if ((off >= dlfb->edid_size) || (count > dlfb->edid_size))
1429                 return 0;
1430
1431         if (off + count > dlfb->edid_size)
1432                 count = dlfb->edid_size - off;
1433
1434         memcpy(buf, dlfb->edid, count);
1435
1436         return count;
1437 }
1438
1439 static ssize_t edid_store(
1440                         struct file *filp,
1441                         struct kobject *kobj, const struct bin_attribute *a,
1442                         char *src, loff_t src_off, size_t src_size) {
1443         struct device *fbdev = kobj_to_dev(kobj);
1444         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1445         struct dlfb_data *dlfb = fb_info->par;
1446         int ret;
1447
1448         /* We only support write of entire EDID at once, no offset*/
1449         if ((src_size != EDID_LENGTH) || (src_off != 0))
1450                 return -EINVAL;
1451
1452         ret = dlfb_setup_modes(dlfb, fb_info, src, src_size);
1453         if (ret)
1454                 return ret;
1455
1456         if (!dlfb->edid || memcmp(src, dlfb->edid, src_size))
1457                 return -EINVAL;
1458
1459         ret = dlfb_ops_set_par(fb_info);
1460         if (ret)
1461                 return ret;
1462
1463         return src_size;
1464 }
1465
1466 static ssize_t metrics_reset_store(struct device *fbdev,
1467                            struct device_attribute *attr,
1468                            const char *buf, size_t count)
1469 {
1470         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1471         struct dlfb_data *dlfb = fb_info->par;
1472
1473         atomic_set(&dlfb->bytes_rendered, 0);
1474         atomic_set(&dlfb->bytes_identical, 0);
1475         atomic_set(&dlfb->bytes_sent, 0);
1476         atomic_set(&dlfb->cpu_kcycles_used, 0);
1477
1478         return count;
1479 }
1480
1481 static const struct bin_attribute edid_attr = {
1482         .attr.name = "edid",
1483         .attr.mode = 0666,
1484         .size = EDID_LENGTH,
1485         .read_new = edid_show,
1486         .write_new = edid_store
1487 };
1488
1489 static const struct device_attribute fb_device_attrs[] = {
1490         __ATTR_RO(metrics_bytes_rendered),
1491         __ATTR_RO(metrics_bytes_identical),
1492         __ATTR_RO(metrics_bytes_sent),
1493         __ATTR_RO(metrics_cpu_kcycles_used),
1494         __ATTR(metrics_reset, S_IWUSR, NULL, metrics_reset_store),
1495 };
1496
1497 /*
1498  * This is necessary before we can communicate with the display controller.
1499  */
1500 static int dlfb_select_std_channel(struct dlfb_data *dlfb)
1501 {
1502         int ret;
1503         static const u8 set_def_chn[] = {
1504                                 0x57, 0xCD, 0xDC, 0xA7,
1505                                 0x1C, 0x88, 0x5E, 0x15,
1506                                 0x60, 0xFE, 0xC6, 0x97,
1507                                 0x16, 0x3D, 0x47, 0xF2  };
1508
1509         ret = usb_control_msg_send(dlfb->udev, 0, NR_USB_REQUEST_CHANNEL,
1510                         (USB_DIR_OUT | USB_TYPE_VENDOR), 0, 0,
1511                         &set_def_chn, sizeof(set_def_chn), USB_CTRL_SET_TIMEOUT,
1512                         GFP_KERNEL);
1513
1514         return ret;
1515 }
1516
1517 static int dlfb_parse_vendor_descriptor(struct dlfb_data *dlfb,
1518                                         struct usb_interface *intf)
1519 {
1520         char *desc;
1521         char *buf;
1522         char *desc_end;
1523         int total_len;
1524
1525         buf = kzalloc(MAX_VENDOR_DESCRIPTOR_SIZE, GFP_KERNEL);
1526         if (!buf)
1527                 return false;
1528         desc = buf;
1529
1530         total_len = usb_get_descriptor(interface_to_usbdev(intf),
1531                                         0x5f, /* vendor specific */
1532                                         0, desc, MAX_VENDOR_DESCRIPTOR_SIZE);
1533
1534         /* if not found, look in configuration descriptor */
1535         if (total_len < 0) {
1536                 if (0 == usb_get_extra_descriptor(intf->cur_altsetting,
1537                         0x5f, &desc))
1538                         total_len = (int) desc[0];
1539         }
1540
1541         if (total_len > 5) {
1542                 dev_info(&intf->dev,
1543                          "vendor descriptor length: %d data: %11ph\n",
1544                          total_len, desc);
1545
1546                 if ((desc[0] != total_len) || /* descriptor length */
1547                     (desc[1] != 0x5f) ||   /* vendor descriptor type */
1548                     (desc[2] != 0x01) ||   /* version (2 bytes) */
1549                     (desc[3] != 0x00) ||
1550                     (desc[4] != total_len - 2)) /* length after type */
1551                         goto unrecognized;
1552
1553                 desc_end = desc + total_len;
1554                 desc += 5; /* the fixed header we've already parsed */
1555
1556                 while (desc < desc_end) {
1557                         u8 length;
1558                         u16 key;
1559
1560                         key = *desc++;
1561                         key |= (u16)*desc++ << 8;
1562                         length = *desc++;
1563
1564                         switch (key) {
1565                         case 0x0200: { /* max_area */
1566                                 u32 max_area = *desc++;
1567                                 max_area |= (u32)*desc++ << 8;
1568                                 max_area |= (u32)*desc++ << 16;
1569                                 max_area |= (u32)*desc++ << 24;
1570                                 dev_warn(&intf->dev,
1571                                          "DL chip limited to %d pixel modes\n",
1572                                          max_area);
1573                                 dlfb->sku_pixel_limit = max_area;
1574                                 break;
1575                         }
1576                         default:
1577                                 break;
1578                         }
1579                         desc += length;
1580                 }
1581         } else {
1582                 dev_info(&intf->dev, "vendor descriptor not available (%d)\n",
1583                          total_len);
1584         }
1585
1586         goto success;
1587
1588 unrecognized:
1589         /* allow udlfb to load for now even if firmware unrecognized */
1590         dev_err(&intf->dev, "Unrecognized vendor firmware descriptor\n");
1591
1592 success:
1593         kfree(buf);
1594         return true;
1595 }
1596
1597 static int dlfb_usb_probe(struct usb_interface *intf,
1598                           const struct usb_device_id *id)
1599 {
1600         int i;
1601         const struct device_attribute *attr;
1602         struct dlfb_data *dlfb;
1603         struct fb_info *info;
1604         int retval;
1605         struct usb_device *usbdev = interface_to_usbdev(intf);
1606         static u8 out_ep[] = {OUT_EP_NUM + USB_DIR_OUT, 0};
1607
1608         /* usb initialization */
1609         dlfb = kzalloc(sizeof(*dlfb), GFP_KERNEL);
1610         if (!dlfb) {
1611                 dev_err(&intf->dev, "%s: failed to allocate dlfb\n", __func__);
1612                 return -ENOMEM;
1613         }
1614
1615         INIT_LIST_HEAD(&dlfb->deferred_free);
1616
1617         dlfb->udev = usb_get_dev(usbdev);
1618         usb_set_intfdata(intf, dlfb);
1619
1620         if (!usb_check_bulk_endpoints(intf, out_ep)) {
1621                 dev_err(&intf->dev, "Invalid DisplayLink device!\n");
1622                 retval = -EINVAL;
1623                 goto error;
1624         }
1625
1626         dev_dbg(&intf->dev, "console enable=%d\n", console);
1627         dev_dbg(&intf->dev, "fb_defio enable=%d\n", fb_defio);
1628         dev_dbg(&intf->dev, "shadow enable=%d\n", shadow);
1629
1630         dlfb->sku_pixel_limit = 2048 * 1152; /* default to maximum */
1631
1632         if (!dlfb_parse_vendor_descriptor(dlfb, intf)) {
1633                 dev_err(&intf->dev,
1634                         "firmware not recognized, incompatible device?\n");
1635                 retval = -ENODEV;
1636                 goto error;
1637         }
1638
1639         if (pixel_limit) {
1640                 dev_warn(&intf->dev,
1641                          "DL chip limit of %d overridden to %d\n",
1642                          dlfb->sku_pixel_limit, pixel_limit);
1643                 dlfb->sku_pixel_limit = pixel_limit;
1644         }
1645
1646
1647         /* allocates framebuffer driver structure, not framebuffer memory */
1648         info = framebuffer_alloc(0, &dlfb->udev->dev);
1649         if (!info) {
1650                 retval = -ENOMEM;
1651                 goto error;
1652         }
1653
1654         dlfb->info = info;
1655         info->par = dlfb;
1656         info->pseudo_palette = dlfb->pseudo_palette;
1657         dlfb->ops = dlfb_ops;
1658         info->fbops = &dlfb->ops;
1659
1660         mutex_init(&dlfb->render_mutex);
1661         dlfb_init_damage(dlfb);
1662         spin_lock_init(&dlfb->damage_lock);
1663         INIT_WORK(&dlfb->damage_work, dlfb_damage_work);
1664
1665         INIT_LIST_HEAD(&info->modelist);
1666
1667         if (!dlfb_alloc_urb_list(dlfb, WRITES_IN_FLIGHT, MAX_TRANSFER)) {
1668                 retval = -ENOMEM;
1669                 dev_err(&intf->dev, "unable to allocate urb list\n");
1670                 goto error;
1671         }
1672
1673         /* We don't register a new USB class. Our client interface is dlfbev */
1674
1675         retval = fb_alloc_cmap(&info->cmap, 256, 0);
1676         if (retval < 0) {
1677                 dev_err(info->device, "cmap allocation failed: %d\n", retval);
1678                 goto error;
1679         }
1680
1681         retval = dlfb_setup_modes(dlfb, info, NULL, 0);
1682         if (retval != 0) {
1683                 dev_err(info->device,
1684                         "unable to find common mode for display and adapter\n");
1685                 goto error;
1686         }
1687
1688         /* ready to begin using device */
1689
1690         atomic_set(&dlfb->usb_active, 1);
1691         dlfb_select_std_channel(dlfb);
1692
1693         dlfb_ops_check_var(&info->var, info);
1694         retval = dlfb_ops_set_par(info);
1695         if (retval)
1696                 goto error;
1697
1698         retval = register_framebuffer(info);
1699         if (retval < 0) {
1700                 dev_err(info->device, "unable to register framebuffer: %d\n",
1701                         retval);
1702                 goto error;
1703         }
1704
1705         for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++) {
1706                 attr = &fb_device_attrs[i];
1707                 retval = device_create_file(info->dev, attr);
1708                 if (retval)
1709                         dev_warn(info->device,
1710                                  "failed to create '%s' attribute: %d\n",
1711                                  attr->attr.name, retval);
1712         }
1713
1714         retval = device_create_bin_file(info->dev, &edid_attr);
1715         if (retval)
1716                 dev_warn(info->device, "failed to create '%s' attribute: %d\n",
1717                          edid_attr.attr.name, retval);
1718
1719         dev_info(info->device,
1720                  "%s is DisplayLink USB device (%dx%d, %dK framebuffer memory)\n",
1721                  dev_name(info->dev), info->var.xres, info->var.yres,
1722                  ((dlfb->backing_buffer) ?
1723                  info->fix.smem_len * 2 : info->fix.smem_len) >> 10);
1724         return 0;
1725
1726 error:
1727         if (dlfb->info) {
1728                 dlfb_ops_destroy(dlfb->info);
1729         } else {
1730                 usb_put_dev(dlfb->udev);
1731                 kfree(dlfb);
1732         }
1733         return retval;
1734 }
1735
1736 static void dlfb_usb_disconnect(struct usb_interface *intf)
1737 {
1738         struct dlfb_data *dlfb;
1739         struct fb_info *info;
1740         int i;
1741
1742         dlfb = usb_get_intfdata(intf);
1743         info = dlfb->info;
1744
1745         dev_dbg(&intf->dev, "USB disconnect starting\n");
1746
1747         /* we virtualize until all fb clients release. Then we free */
1748         dlfb->virtualized = true;
1749
1750         /* When non-active we'll update virtual framebuffer, but no new urbs */
1751         atomic_set(&dlfb->usb_active, 0);
1752
1753         /* this function will wait for all in-flight urbs to complete */
1754         dlfb_free_urb_list(dlfb);
1755
1756         /* remove udlfb's sysfs interfaces */
1757         for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
1758                 device_remove_file(info->dev, &fb_device_attrs[i]);
1759         device_remove_bin_file(info->dev, &edid_attr);
1760
1761         unregister_framebuffer(info);
1762 }
1763
1764 static struct usb_driver dlfb_driver = {
1765         .name = "udlfb",
1766         .probe = dlfb_usb_probe,
1767         .disconnect = dlfb_usb_disconnect,
1768         .id_table = id_table,
1769 };
1770
1771 module_usb_driver(dlfb_driver);
1772
1773 static void dlfb_urb_completion(struct urb *urb)
1774 {
1775         struct urb_node *unode = urb->context;
1776         struct dlfb_data *dlfb = unode->dlfb;
1777         unsigned long flags;
1778
1779         switch (urb->status) {
1780         case 0:
1781                 /* success */
1782                 break;
1783         case -ECONNRESET:
1784         case -ENOENT:
1785         case -ESHUTDOWN:
1786                 /* sync/async unlink faults aren't errors */
1787                 break;
1788         default:
1789                 dev_err(&dlfb->udev->dev,
1790                         "%s - nonzero write bulk status received: %d\n",
1791                         __func__, urb->status);
1792                 atomic_set(&dlfb->lost_pixels, 1);
1793                 break;
1794         }
1795
1796         urb->transfer_buffer_length = dlfb->urbs.size; /* reset to actual */
1797
1798         spin_lock_irqsave(&dlfb->urbs.lock, flags);
1799         list_add_tail(&unode->entry, &dlfb->urbs.list);
1800         dlfb->urbs.available++;
1801         spin_unlock_irqrestore(&dlfb->urbs.lock, flags);
1802
1803         up(&dlfb->urbs.limit_sem);
1804 }
1805
1806 static void dlfb_free_urb_list(struct dlfb_data *dlfb)
1807 {
1808         int count = dlfb->urbs.count;
1809         struct list_head *node;
1810         struct urb_node *unode;
1811         struct urb *urb;
1812
1813         /* keep waiting and freeing, until we've got 'em all */
1814         while (count--) {
1815                 down(&dlfb->urbs.limit_sem);
1816
1817                 spin_lock_irq(&dlfb->urbs.lock);
1818
1819                 node = dlfb->urbs.list.next; /* have reserved one with sem */
1820                 list_del_init(node);
1821
1822                 spin_unlock_irq(&dlfb->urbs.lock);
1823
1824                 unode = list_entry(node, struct urb_node, entry);
1825                 urb = unode->urb;
1826
1827                 /* Free each separately allocated piece */
1828                 usb_free_coherent(urb->dev, dlfb->urbs.size,
1829                                   urb->transfer_buffer, urb->transfer_dma);
1830                 usb_free_urb(urb);
1831                 kfree(node);
1832         }
1833
1834         dlfb->urbs.count = 0;
1835 }
1836
1837 static int dlfb_alloc_urb_list(struct dlfb_data *dlfb, int count, size_t size)
1838 {
1839         struct urb *urb;
1840         struct urb_node *unode;
1841         char *buf;
1842         size_t wanted_size = count * size;
1843
1844         spin_lock_init(&dlfb->urbs.lock);
1845
1846 retry:
1847         dlfb->urbs.size = size;
1848         INIT_LIST_HEAD(&dlfb->urbs.list);
1849
1850         sema_init(&dlfb->urbs.limit_sem, 0);
1851         dlfb->urbs.count = 0;
1852         dlfb->urbs.available = 0;
1853
1854         while (dlfb->urbs.count * size < wanted_size) {
1855                 unode = kzalloc(sizeof(*unode), GFP_KERNEL);
1856                 if (!unode)
1857                         break;
1858                 unode->dlfb = dlfb;
1859
1860                 urb = usb_alloc_urb(0, GFP_KERNEL);
1861                 if (!urb) {
1862                         kfree(unode);
1863                         break;
1864                 }
1865                 unode->urb = urb;
1866
1867                 buf = usb_alloc_coherent(dlfb->udev, size, GFP_KERNEL,
1868                                          &urb->transfer_dma);
1869                 if (!buf) {
1870                         kfree(unode);
1871                         usb_free_urb(urb);
1872                         if (size > PAGE_SIZE) {
1873                                 size /= 2;
1874                                 dlfb_free_urb_list(dlfb);
1875                                 goto retry;
1876                         }
1877                         break;
1878                 }
1879
1880                 /* urb->transfer_buffer_length set to actual before submit */
1881                 usb_fill_bulk_urb(urb, dlfb->udev,
1882                         usb_sndbulkpipe(dlfb->udev, OUT_EP_NUM),
1883                         buf, size, dlfb_urb_completion, unode);
1884                 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
1885
1886                 list_add_tail(&unode->entry, &dlfb->urbs.list);
1887
1888                 up(&dlfb->urbs.limit_sem);
1889                 dlfb->urbs.count++;
1890                 dlfb->urbs.available++;
1891         }
1892
1893         return dlfb->urbs.count;
1894 }
1895
1896 static struct urb *dlfb_get_urb(struct dlfb_data *dlfb)
1897 {
1898         int ret;
1899         struct list_head *entry;
1900         struct urb_node *unode;
1901
1902         /* Wait for an in-flight buffer to complete and get re-queued */
1903         ret = down_timeout(&dlfb->urbs.limit_sem, GET_URB_TIMEOUT);
1904         if (ret) {
1905                 atomic_set(&dlfb->lost_pixels, 1);
1906                 dev_warn(&dlfb->udev->dev,
1907                          "wait for urb interrupted: %d available: %d\n",
1908                          ret, dlfb->urbs.available);
1909                 return NULL;
1910         }
1911
1912         spin_lock_irq(&dlfb->urbs.lock);
1913
1914         BUG_ON(list_empty(&dlfb->urbs.list)); /* reserved one with limit_sem */
1915         entry = dlfb->urbs.list.next;
1916         list_del_init(entry);
1917         dlfb->urbs.available--;
1918
1919         spin_unlock_irq(&dlfb->urbs.lock);
1920
1921         unode = list_entry(entry, struct urb_node, entry);
1922         return unode->urb;
1923 }
1924
1925 static int dlfb_submit_urb(struct dlfb_data *dlfb, struct urb *urb, size_t len)
1926 {
1927         int ret;
1928
1929         BUG_ON(len > dlfb->urbs.size);
1930
1931         urb->transfer_buffer_length = len; /* set to actual payload len */
1932         ret = usb_submit_urb(urb, GFP_KERNEL);
1933         if (ret) {
1934                 dlfb_urb_completion(urb); /* because no one else will */
1935                 atomic_set(&dlfb->lost_pixels, 1);
1936                 dev_err(&dlfb->udev->dev, "submit urb error: %d\n", ret);
1937         }
1938         return ret;
1939 }
1940
1941 module_param(console, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1942 MODULE_PARM_DESC(console, "Allow fbcon to open framebuffer");
1943
1944 module_param(fb_defio, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1945 MODULE_PARM_DESC(fb_defio, "Page fault detection of mmap writes");
1946
1947 module_param(shadow, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1948 MODULE_PARM_DESC(shadow, "Shadow vid mem. Disable to save mem but lose perf");
1949
1950 module_param(pixel_limit, int, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1951 MODULE_PARM_DESC(pixel_limit, "Force limit on max mode (in x*y pixels)");
1952
1953 MODULE_AUTHOR("Roberto De Ioris <[email protected]>, "
1954               "Jaya Kumar <[email protected]>, "
1955               "Bernie Thompson <[email protected]>");
1956 MODULE_DESCRIPTION("DisplayLink kernel framebuffer driver");
1957 MODULE_LICENSE("GPL");
1958