drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c

   1 /**
   2  * Copyright (c) 2010-2012 Broadcom. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions, and the following disclaimer,
   9  *    without modification.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. The names of the above-listed copyright holders may not be used
  14  *    to endorse or promote products derived from this software without
  15  *    specific prior written permission.
  16  *
  17  * ALTERNATIVELY, this software may be distributed under the terms of the
  18  * GNU General Public License ("GPL") version 2, as published by the Free
  19  * Software Foundation.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  22  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  23  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  24  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  25  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  26  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  27  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  28  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  29  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  30  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  31  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <linux/kernel.h>
  35 #include <linux/types.h>
  36 #include <linux/errno.h>
  37 #include <linux/interrupt.h>
  38 #include <linux/pagemap.h>
  39 #include <linux/dma-mapping.h>
  40 #include <linux/io.h>
  41 #include <linux/platform_device.h>
  42 #include <linux/uaccess.h>
  43 #include <linux/mm.h>
  44 #include <linux/of.h>
  45 #include <soc/bcm2835/raspberrypi-firmware.h>
  46
  47 #define TOTAL_SLOTS (VCHIQ_SLOT_ZERO_SLOTS + 2 * 32)
  48
  49 #include "vchiq_arm.h"
  50 #include "vchiq_connected.h"
  51 #include "vchiq_killable.h"
  52 #include "vchiq_pagelist.h"
  53
  54 #define MAX_FRAGMENTS (VCHIQ_NUM_CURRENT_BULKS * 2)
  55
  56 #define VCHIQ_PLATFORM_FRAGMENTS_OFFSET_IDX 0
  57 #define VCHIQ_PLATFORM_FRAGMENTS_COUNT_IDX  1
  58
  59 #define BELL0   0x00
  60 #define BELL2   0x08
  61
  62 struct vchiq_2835_state {
  63         int inited;
  64         VCHIQ_ARM_STATE_T arm_state;
  65 };
  66
  67 struct vchiq_pagelist_info {
  68         PAGELIST_T *pagelist;
  69         size_t pagelist_buffer_size;
  70         dma_addr_t dma_addr;
  71         enum dma_data_direction dma_dir;
  72         unsigned int num_pages;
  73         unsigned int pages_need_release;
  74         struct page **pages;
  75         struct scatterlist *scatterlist;
  76         unsigned int scatterlist_mapped;
  77 };
  78
  79 static void __iomem *g_regs;
  80 static unsigned int g_cache_line_size = sizeof(CACHE_LINE_SIZE);
  81 static unsigned int g_fragments_size;
  82 static char *g_fragments_base;
  83 static char *g_free_fragments;
  84 static struct semaphore g_free_fragments_sema;
  85 static struct device *g_dev;
  86
  87 static DEFINE_SEMAPHORE(g_free_fragments_mutex);
  88
  89 static irqreturn_t
  90 vchiq_doorbell_irq(int irq, void *dev_id);
  91
  92 static struct vchiq_pagelist_info *
  93 create_pagelist(char __user *buf, size_t count, unsigned short type);
  94
  95 static void
  96 free_pagelist(struct vchiq_pagelist_info *pagelistinfo,
  97               int actual);
  98
  99 int vchiq_platform_init(struct platform_device *pdev, VCHIQ_STATE_T *state)
 100 {
 101         struct device *dev = &pdev->dev;
 102         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 103         VCHIQ_SLOT_ZERO_T *vchiq_slot_zero;
 104         struct resource *res;
 105         void *slot_mem;
 106         dma_addr_t slot_phys;
 107         u32 channelbase;
 108         int slot_mem_size, frag_mem_size;
 109         int err, irq, i;
 110
 111         /*
 112          * VCHI messages between the CPU and firmware use
 113          * 32-bit bus addresses.
 114          */
 115         err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
 116
 117         if (err < 0)
 118                 return err;
 119
 120         err = of_property_read_u32(dev->of_node, "cache-line-size",
 121                                    &g_cache_line_size);
 122
 123         if (err) {
 124                 dev_err(dev, "Missing cache-line-size property\n");
 125                 return -ENODEV;
 126         }
 127
 128         g_fragments_size = 2 * g_cache_line_size;
 129
 130         /* Allocate space for the channels in coherent memory */
 131         slot_mem_size = PAGE_ALIGN(TOTAL_SLOTS * VCHIQ_SLOT_SIZE);
 132         frag_mem_size = PAGE_ALIGN(g_fragments_size * MAX_FRAGMENTS);
 133
 134         slot_mem = dmam_alloc_coherent(dev, slot_mem_size + frag_mem_size,
 135                                        &slot_phys, GFP_KERNEL);
 136         if (!slot_mem) {
 137                 dev_err(dev, "could not allocate DMA memory\n");
 138                 return -ENOMEM;
 139         }
 140
 141         WARN_ON(((unsigned long)slot_mem & (PAGE_SIZE - 1)) != 0);
 142
 143         vchiq_slot_zero = vchiq_init_slots(slot_mem, slot_mem_size);
 144         if (!vchiq_slot_zero)
 145                 return -EINVAL;
 146
 147         vchiq_slot_zero->platform_data[VCHIQ_PLATFORM_FRAGMENTS_OFFSET_IDX] =
 148                 (int)slot_phys + slot_mem_size;
 149         vchiq_slot_zero->platform_data[VCHIQ_PLATFORM_FRAGMENTS_COUNT_IDX] =
 150                 MAX_FRAGMENTS;
 151
 152         g_fragments_base = (char *)slot_mem + slot_mem_size;
 153
 154         g_free_fragments = g_fragments_base;
 155         for (i = 0; i < (MAX_FRAGMENTS - 1); i++) {
 156                 *(char **)&g_fragments_base[i*g_fragments_size] =
 157                         &g_fragments_base[(i + 1)*g_fragments_size];
 158         }
 159         *(char **)&g_fragments_base[i * g_fragments_size] = NULL;
 160         sema_init(&g_free_fragments_sema, MAX_FRAGMENTS);
 161
 162         if (vchiq_init_state(state, vchiq_slot_zero, 0) != VCHIQ_SUCCESS)
 163                 return -EINVAL;
 164
 165         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 166         g_regs = devm_ioremap_resource(&pdev->dev, res);
 167         if (IS_ERR(g_regs))
 168                 return PTR_ERR(g_regs);
 169
 170         irq = platform_get_irq(pdev, 0);
 171         if (irq <= 0) {
 172                 dev_err(dev, "failed to get IRQ\n");
 173                 return irq;
 174         }
 175
 176         err = devm_request_irq(dev, irq, vchiq_doorbell_irq, IRQF_IRQPOLL,
 177                                "VCHIQ doorbell", state);
 178         if (err) {
 179                 dev_err(dev, "failed to register irq=%d\n", irq);
 180                 return err;
 181         }
 182
 183         /* Send the base address of the slots to VideoCore */
 184         channelbase = slot_phys;
 185         err = rpi_firmware_property(fw, RPI_FIRMWARE_VCHIQ_INIT,
 186                                     &channelbase, sizeof(channelbase));
 187         if (err || channelbase) {
 188                 dev_err(dev, "failed to set channelbase\n");
 189                 return err ? : -ENXIO;
 190         }
 191
 192         g_dev = dev;
 193         vchiq_log_info(vchiq_arm_log_level,
 194                 "vchiq_init - done (slots %pK, phys %pad)",
 195                 vchiq_slot_zero, &slot_phys);
 196
 197         vchiq_call_connected_callbacks();
 198
 199         return 0;
 200 }
 201
 202 VCHIQ_STATUS_T
 203 vchiq_platform_init_state(VCHIQ_STATE_T *state)
 204 {
 205         VCHIQ_STATUS_T status = VCHIQ_SUCCESS;
 206         struct vchiq_2835_state *platform_state;
 207
 208         state->platform_state = kzalloc(sizeof(*platform_state), GFP_KERNEL);
 209         platform_state = (struct vchiq_2835_state *)state->platform_state;
 210
 211         platform_state->inited = 1;
 212         status = vchiq_arm_init_state(state, &platform_state->arm_state);
 213
 214         if (status != VCHIQ_SUCCESS)
 215                 platform_state->inited = 0;
 216
 217         return status;
 218 }
 219
 220 VCHIQ_ARM_STATE_T*
 221 vchiq_platform_get_arm_state(VCHIQ_STATE_T *state)
 222 {
 223         struct vchiq_2835_state *platform_state;
 224
 225         platform_state   = (struct vchiq_2835_state *)state->platform_state;
 226
 227         if (!platform_state->inited)
 228                 BUG();
 229
 230         return &platform_state->arm_state;
 231 }
 232
 233 void
 234 remote_event_signal(REMOTE_EVENT_T *event)
 235 {
 236         wmb();
 237
 238         event->fired = 1;
 239
 240         dsb(sy);         /* data barrier operation */
 241
 242         if (event->armed)
 243                 writel(0, g_regs + BELL2); /* trigger vc interrupt */
 244 }
 245
 246 VCHIQ_STATUS_T
 247 vchiq_prepare_bulk_data(VCHIQ_BULK_T *bulk, VCHI_MEM_HANDLE_T memhandle,
 248         void *offset, int size, int dir)
 249 {
 250         struct vchiq_pagelist_info *pagelistinfo;
 251
 252         WARN_ON(memhandle != VCHI_MEM_HANDLE_INVALID);
 253
 254         pagelistinfo = create_pagelist((char __user *)offset, size,
 255                                        (dir == VCHIQ_BULK_RECEIVE)
 256                                        ? PAGELIST_READ
 257                                        : PAGELIST_WRITE);
 258
 259         if (!pagelistinfo)
 260                 return VCHIQ_ERROR;
 261
 262         bulk->handle = memhandle;
 263         bulk->data = (void *)(unsigned long)pagelistinfo->dma_addr;
 264
 265         /*
 266          * Store the pagelistinfo address in remote_data,
 267          * which isn't used by the slave.
 268          */
 269         bulk->remote_data = pagelistinfo;
 270
 271         return VCHIQ_SUCCESS;
 272 }
 273
 274 void
 275 vchiq_complete_bulk(VCHIQ_BULK_T *bulk)
 276 {
 277         if (bulk && bulk->remote_data && bulk->actual)
 278                 free_pagelist((struct vchiq_pagelist_info *)bulk->remote_data,
 279                               bulk->actual);
 280 }
 281
 282 void
 283 vchiq_transfer_bulk(VCHIQ_BULK_T *bulk)
 284 {
 285         /*
 286          * This should only be called on the master (VideoCore) side, but
 287          * provide an implementation to avoid the need for ifdefery.
 288          */
 289         BUG();
 290 }
 291
 292 void
 293 vchiq_dump_platform_state(void *dump_context)
 294 {
 295         char buf[80];
 296         int len;
 297
 298         len = snprintf(buf, sizeof(buf),
 299                 "  Platform: 2835 (VC master)");
 300         vchiq_dump(dump_context, buf, len + 1);
 301 }
 302
 303 VCHIQ_STATUS_T
 304 vchiq_platform_suspend(VCHIQ_STATE_T *state)
 305 {
 306         return VCHIQ_ERROR;
 307 }
 308
 309 VCHIQ_STATUS_T
 310 vchiq_platform_resume(VCHIQ_STATE_T *state)
 311 {
 312         return VCHIQ_SUCCESS;
 313 }
 314
 315 void
 316 vchiq_platform_paused(VCHIQ_STATE_T *state)
 317 {
 318 }
 319
 320 void
 321 vchiq_platform_resumed(VCHIQ_STATE_T *state)
 322 {
 323 }
 324
 325 int
 326 vchiq_platform_videocore_wanted(VCHIQ_STATE_T *state)
 327 {
 328         return 1; // autosuspend not supported - videocore always wanted
 329 }
 330
 331 int
 332 vchiq_platform_use_suspend_timer(void)
 333 {
 334         return 0;
 335 }
 336 void
 337 vchiq_dump_platform_use_state(VCHIQ_STATE_T *state)
 338 {
 339         vchiq_log_info(vchiq_arm_log_level, "Suspend timer not in use");
 340 }
 341 void
 342 vchiq_platform_handle_timeout(VCHIQ_STATE_T *state)
 343 {
 344         (void)state;
 345 }
 346 /*
 347  * Local functions
 348  */
 349
 350 static irqreturn_t
 351 vchiq_doorbell_irq(int irq, void *dev_id)
 352 {
 353         VCHIQ_STATE_T *state = dev_id;
 354         irqreturn_t ret = IRQ_NONE;
 355         unsigned int status;
 356
 357         /* Read (and clear) the doorbell */
 358         status = readl(g_regs + BELL0);
 359
 360         if (status & 0x4) {  /* Was the doorbell rung? */
 361                 remote_event_pollall(state);
 362                 ret = IRQ_HANDLED;
 363         }
 364
 365         return ret;
 366 }
 367
 368 static void
 369 cleanup_pagelistinfo(struct vchiq_pagelist_info *pagelistinfo)
 370 {
 371         if (pagelistinfo->scatterlist_mapped) {
 372                 dma_unmap_sg(g_dev, pagelistinfo->scatterlist,
 373                              pagelistinfo->num_pages, pagelistinfo->dma_dir);
 374         }
 375
 376         if (pagelistinfo->pages_need_release) {
 377                 unsigned int i;
 378
 379                 for (i = 0; i < pagelistinfo->num_pages; i++)
 380                         put_page(pagelistinfo->pages[i]);
 381         }
 382
 383         dma_free_coherent(g_dev, pagelistinfo->pagelist_buffer_size,
 384                           pagelistinfo->pagelist, pagelistinfo->dma_addr);
 385 }
 386
 387 /* There is a potential problem with partial cache lines (pages?)
 388  * at the ends of the block when reading. If the CPU accessed anything in
 389  * the same line (page?) then it may have pulled old data into the cache,
 390  * obscuring the new data underneath. We can solve this by transferring the
 391  * partial cache lines separately, and allowing the ARM to copy into the
 392  * cached area.
 393  */
 394
 395 static struct vchiq_pagelist_info *
 396 create_pagelist(char __user *buf, size_t count, unsigned short type)
 397 {
 398         PAGELIST_T *pagelist;
 399         struct vchiq_pagelist_info *pagelistinfo;
 400         struct page **pages;
 401         u32 *addrs;
 402         unsigned int num_pages, offset, i, k;
 403         int actual_pages;
 404         size_t pagelist_size;
 405         struct scatterlist *scatterlist, *sg;
 406         int dma_buffers;
 407         dma_addr_t dma_addr;
 408
 409         offset = ((unsigned int)(unsigned long)buf & (PAGE_SIZE - 1));
 410         num_pages = DIV_ROUND_UP(count + offset, PAGE_SIZE);
 411
 412         pagelist_size = sizeof(PAGELIST_T) +
 413                         (num_pages * sizeof(u32)) +
 414                         (num_pages * sizeof(pages[0]) +
 415                         (num_pages * sizeof(struct scatterlist))) +
 416                         sizeof(struct vchiq_pagelist_info);
 417
 418         /* Allocate enough storage to hold the page pointers and the page
 419          * list
 420          */
 421         pagelist = dma_zalloc_coherent(g_dev,
 422                                        pagelist_size,
 423                                        &dma_addr,
 424                                        GFP_KERNEL);
 425
 426         vchiq_log_trace(vchiq_arm_log_level, "%s - %pK", __func__, pagelist);
 427
 428         if (!pagelist)
 429                 return NULL;
 430
 431         addrs           = pagelist->addrs;
 432         pages           = (struct page **)(addrs + num_pages);
 433         scatterlist     = (struct scatterlist *)(pages + num_pages);
 434         pagelistinfo    = (struct vchiq_pagelist_info *)
 435                           (scatterlist + num_pages);
 436
 437         pagelist->length = count;
 438         pagelist->type = type;
 439         pagelist->offset = offset;
 440
 441         /* Populate the fields of the pagelistinfo structure */
 442         pagelistinfo->pagelist = pagelist;
 443         pagelistinfo->pagelist_buffer_size = pagelist_size;
 444         pagelistinfo->dma_addr = dma_addr;
 445         pagelistinfo->dma_dir =  (type == PAGELIST_WRITE) ?
 446                                   DMA_TO_DEVICE : DMA_FROM_DEVICE;
 447         pagelistinfo->num_pages = num_pages;
 448         pagelistinfo->pages_need_release = 0;
 449         pagelistinfo->pages = pages;
 450         pagelistinfo->scatterlist = scatterlist;
 451         pagelistinfo->scatterlist_mapped = 0;
 452
 453         if (is_vmalloc_addr(buf)) {
 454                 unsigned long length = count;
 455                 unsigned int off = offset;
 456
 457                 for (actual_pages = 0; actual_pages < num_pages;
 458                      actual_pages++) {
 459                         struct page *pg = vmalloc_to_page(buf + (actual_pages *
 460                                                                  PAGE_SIZE));
 461                         size_t bytes = PAGE_SIZE - off;
 462
 463                         if (!pg) {
 464                                 cleanup_pagelistinfo(pagelistinfo);
 465                                 return NULL;
 466                         }
 467
 468                         if (bytes > length)
 469                                 bytes = length;
 470                         pages[actual_pages] = pg;
 471                         length -= bytes;
 472                         off = 0;
 473                 }
 474                 /* do not try and release vmalloc pages */
 475         } else {
 476                 actual_pages = get_user_pages_fast(
 477                                           (unsigned long)buf & PAGE_MASK,
 478                                           num_pages,
 479                                           type == PAGELIST_READ,
 480                                           pages);
 481
 482                 if (actual_pages != num_pages) {
 483                         vchiq_log_info(vchiq_arm_log_level,
 484                                        "%s - only %d/%d pages locked",
 485                                        __func__, actual_pages, num_pages);
 486
 487                         /* This is probably due to the process being killed */
 488                         while (actual_pages > 0)
 489                         {
 490                                 actual_pages--;
 491                                 put_page(pages[actual_pages]);
 492                         }
 493                         cleanup_pagelistinfo(pagelistinfo);
 494                         return NULL;
 495                 }
 496                  /* release user pages */
 497                 pagelistinfo->pages_need_release = 1;
 498         }
 499
 500         /*
 501          * Initialize the scatterlist so that the magic cookie
 502          *  is filled if debugging is enabled
 503          */
 504         sg_init_table(scatterlist, num_pages);
 505         /* Now set the pages for each scatterlist */
 506         for (i = 0; i < num_pages; i++) {
 507                 unsigned int len = PAGE_SIZE - offset;
 508
 509                 if (len > count)
 510                         len = count;
 511                 sg_set_page(scatterlist + i, pages[i], len, offset);
 512                 offset = 0;
 513                 count -= len;
 514         }
 515
 516         dma_buffers = dma_map_sg(g_dev,
 517                                  scatterlist,
 518                                  num_pages,
 519                                  pagelistinfo->dma_dir);
 520
 521         if (dma_buffers == 0) {
 522                 cleanup_pagelistinfo(pagelistinfo);
 523                 return NULL;
 524         }
 525
 526         pagelistinfo->scatterlist_mapped = 1;
 527
 528         /* Combine adjacent blocks for performance */
 529         k = 0;
 530         for_each_sg(scatterlist, sg, dma_buffers, i) {
 531                 u32 len = sg_dma_len(sg);
 532                 u32 addr = sg_dma_address(sg);
 533
 534                 /* Note: addrs is the address + page_count - 1
 535                  * The firmware expects blocks after the first to be page-
 536                  * aligned and a multiple of the page size
 537                  */
 538                 WARN_ON(len == 0);
 539                 WARN_ON(i && (i != (dma_buffers - 1)) && (len & ~PAGE_MASK));
 540                 WARN_ON(i && (addr & ~PAGE_MASK));
 541                 if (k > 0 &&
 542                     ((addrs[k - 1] & PAGE_MASK) +
 543                      (((addrs[k - 1] & ~PAGE_MASK) + 1) << PAGE_SHIFT))
 544                     == (addr & PAGE_MASK))
 545                         addrs[k - 1] += ((len + PAGE_SIZE - 1) >> PAGE_SHIFT);
 546                 else
 547                         addrs[k++] = (addr & PAGE_MASK) |
 548                                 (((len + PAGE_SIZE - 1) >> PAGE_SHIFT) - 1);
 549         }
 550
 551         /* Partial cache lines (fragments) require special measures */
 552         if ((type == PAGELIST_READ) &&
 553                 ((pagelist->offset & (g_cache_line_size - 1)) ||
 554                 ((pagelist->offset + pagelist->length) &
 555                 (g_cache_line_size - 1)))) {
 556                 char *fragments;
 557
 558                 if (down_interruptible(&g_free_fragments_sema) != 0) {
 559                         cleanup_pagelistinfo(pagelistinfo);
 560                         return NULL;
 561                 }
 562
 563                 WARN_ON(g_free_fragments == NULL);
 564
 565                 down(&g_free_fragments_mutex);
 566                 fragments = g_free_fragments;
 567                 WARN_ON(fragments == NULL);
 568                 g_free_fragments = *(char **) g_free_fragments;
 569                 up(&g_free_fragments_mutex);
 570                 pagelist->type = PAGELIST_READ_WITH_FRAGMENTS +
 571                         (fragments - g_fragments_base) / g_fragments_size;
 572         }
 573
 574         return pagelistinfo;
 575 }
 576
 577 static void
 578 free_pagelist(struct vchiq_pagelist_info *pagelistinfo,
 579               int actual)
 580 {
 581         PAGELIST_T *pagelist   = pagelistinfo->pagelist;
 582         struct page **pages    = pagelistinfo->pages;
 583         unsigned int num_pages = pagelistinfo->num_pages;
 584
 585         vchiq_log_trace(vchiq_arm_log_level, "free_pagelist - %pK, %d",
 586                         pagelistinfo->pagelist, actual);
 587
 588         /*
 589          * NOTE: dma_unmap_sg must be called before the
 590          * cpu can touch any of the data/pages.
 591          */
 592         dma_unmap_sg(g_dev, pagelistinfo->scatterlist,
 593                      pagelistinfo->num_pages, pagelistinfo->dma_dir);
 594         pagelistinfo->scatterlist_mapped = 0;
 595
 596         /* Deal with any partial cache lines (fragments) */
 597         if (pagelist->type >= PAGELIST_READ_WITH_FRAGMENTS) {
 598                 char *fragments = g_fragments_base +
 599                         (pagelist->type - PAGELIST_READ_WITH_FRAGMENTS) *
 600                         g_fragments_size;
 601                 int head_bytes, tail_bytes;
 602
 603                 head_bytes = (g_cache_line_size - pagelist->offset) &
 604                         (g_cache_line_size - 1);
 605                 tail_bytes = (pagelist->offset + actual) &
 606                         (g_cache_line_size - 1);
 607
 608                 if ((actual >= 0) && (head_bytes != 0)) {
 609                         if (head_bytes > actual)
 610                                 head_bytes = actual;
 611
 612                         memcpy((char *)kmap(pages[0]) +
 613                                 pagelist->offset,
 614                                 fragments,
 615                                 head_bytes);
 616                         kunmap(pages[0]);
 617                 }
 618                 if ((actual >= 0) && (head_bytes < actual) &&
 619                         (tail_bytes != 0)) {
 620                         memcpy((char *)kmap(pages[num_pages - 1]) +
 621                                 ((pagelist->offset + actual) &
 622                                 (PAGE_SIZE - 1) & ~(g_cache_line_size - 1)),
 623                                 fragments + g_cache_line_size,
 624                                 tail_bytes);
 625                         kunmap(pages[num_pages - 1]);
 626                 }
 627
 628                 down(&g_free_fragments_mutex);
 629                 *(char **)fragments = g_free_fragments;
 630                 g_free_fragments = fragments;
 631                 up(&g_free_fragments_mutex);
 632                 up(&g_free_fragments_sema);
 633         }
 634
 635         /* Need to mark all the pages dirty. */
 636         if (pagelist->type != PAGELIST_WRITE &&
 637             pagelistinfo->pages_need_release) {
 638                 unsigned int i;
 639
 640                 for (i = 0; i < num_pages; i++)
 641                         set_page_dirty(pages[i]);
 642         }
 643
 644         cleanup_pagelistinfo(pagelistinfo);
 645 }