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 typedef struct vchiq_2835_state_struct {
  63         int inited;
  64         VCHIQ_ARM_STATE_T arm_state;
  65 } VCHIQ_2835_ARM_STATE_T;
  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 extern int vchiq_arm_log_level;
  88
  89 static DEFINE_SEMAPHORE(g_free_fragments_mutex);
  90
  91 static irqreturn_t
  92 vchiq_doorbell_irq(int irq, void *dev_id);
  93
  94 static struct vchiq_pagelist_info *
  95 create_pagelist(char __user *buf, size_t count, unsigned short type,
  96                 struct task_struct *task);
  97
  98 static void
  99 free_pagelist(struct vchiq_pagelist_info *pagelistinfo,
 100               int actual);
 101
 102 int vchiq_platform_init(struct platform_device *pdev, VCHIQ_STATE_T *state)
 103 {
 104         struct device *dev = &pdev->dev;
 105         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 106         VCHIQ_SLOT_ZERO_T *vchiq_slot_zero;
 107         struct resource *res;
 108         void *slot_mem;
 109         dma_addr_t slot_phys;
 110         u32 channelbase;
 111         int slot_mem_size, frag_mem_size;
 112         int err, irq, i;
 113
 114         /*
 115          * VCHI messages between the CPU and firmware use
 116          * 32-bit bus addresses.
 117          */
 118         err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
 119
 120         if (err < 0)
 121                 return err;
 122
 123         err = of_property_read_u32(dev->of_node, "cache-line-size",
 124                                    &g_cache_line_size);
 125
 126         if (err) {
 127                 dev_err(dev, "Missing cache-line-size property\n");
 128                 return -ENODEV;
 129         }
 130
 131         g_fragments_size = 2 * g_cache_line_size;
 132
 133         /* Allocate space for the channels in coherent memory */
 134         slot_mem_size = PAGE_ALIGN(TOTAL_SLOTS * VCHIQ_SLOT_SIZE);
 135         frag_mem_size = PAGE_ALIGN(g_fragments_size * MAX_FRAGMENTS);
 136
 137         slot_mem = dmam_alloc_coherent(dev, slot_mem_size + frag_mem_size,
 138                                        &slot_phys, GFP_KERNEL);
 139         if (!slot_mem) {
 140                 dev_err(dev, "could not allocate DMA memory\n");
 141                 return -ENOMEM;
 142         }
 143
 144         WARN_ON(((unsigned long)slot_mem & (PAGE_SIZE - 1)) != 0);
 145
 146         vchiq_slot_zero = vchiq_init_slots(slot_mem, slot_mem_size);
 147         if (!vchiq_slot_zero)
 148                 return -EINVAL;
 149
 150         vchiq_slot_zero->platform_data[VCHIQ_PLATFORM_FRAGMENTS_OFFSET_IDX] =
 151                 (int)slot_phys + slot_mem_size;
 152         vchiq_slot_zero->platform_data[VCHIQ_PLATFORM_FRAGMENTS_COUNT_IDX] =
 153                 MAX_FRAGMENTS;
 154
 155         g_fragments_base = (char *)slot_mem + slot_mem_size;
 156
 157         g_free_fragments = g_fragments_base;
 158         for (i = 0; i < (MAX_FRAGMENTS - 1); i++) {
 159                 *(char **)&g_fragments_base[i*g_fragments_size] =
 160                         &g_fragments_base[(i + 1)*g_fragments_size];
 161         }
 162         *(char **)&g_fragments_base[i * g_fragments_size] = NULL;
 163         sema_init(&g_free_fragments_sema, MAX_FRAGMENTS);
 164
 165         if (vchiq_init_state(state, vchiq_slot_zero, 0) != VCHIQ_SUCCESS)
 166                 return -EINVAL;
 167
 168         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 169         g_regs = devm_ioremap_resource(&pdev->dev, res);
 170         if (IS_ERR(g_regs))
 171                 return PTR_ERR(g_regs);
 172
 173         irq = platform_get_irq(pdev, 0);
 174         if (irq <= 0) {
 175                 dev_err(dev, "failed to get IRQ\n");
 176                 return irq;
 177         }
 178
 179         err = devm_request_irq(dev, irq, vchiq_doorbell_irq, IRQF_IRQPOLL,
 180                                "VCHIQ doorbell", state);
 181         if (err) {
 182                 dev_err(dev, "failed to register irq=%d\n", irq);
 183                 return err;
 184         }
 185
 186         /* Send the base address of the slots to VideoCore */
 187         channelbase = slot_phys;
 188         err = rpi_firmware_property(fw, RPI_FIRMWARE_VCHIQ_INIT,
 189                                     &channelbase, sizeof(channelbase));
 190         if (err || channelbase) {
 191                 dev_err(dev, "failed to set channelbase\n");
 192                 return err ? : -ENXIO;
 193         }
 194
 195         g_dev = dev;
 196         vchiq_log_info(vchiq_arm_log_level,
 197                 "vchiq_init - done (slots %pK, phys %pad)",
 198                 vchiq_slot_zero, &slot_phys);
 199
 200         vchiq_call_connected_callbacks();
 201
 202         return 0;
 203 }
 204
 205 VCHIQ_STATUS_T
 206 vchiq_platform_init_state(VCHIQ_STATE_T *state)
 207 {
 208         VCHIQ_STATUS_T status = VCHIQ_SUCCESS;
 209
 210         state->platform_state = kzalloc(sizeof(VCHIQ_2835_ARM_STATE_T), GFP_KERNEL);
 211         ((VCHIQ_2835_ARM_STATE_T *)state->platform_state)->inited = 1;
 212         status = vchiq_arm_init_state(state, &((VCHIQ_2835_ARM_STATE_T *)state->platform_state)->arm_state);
 213         if (status != VCHIQ_SUCCESS)
 214         {
 215                 ((VCHIQ_2835_ARM_STATE_T *)state->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         if (!((VCHIQ_2835_ARM_STATE_T *)state->platform_state)->inited)
 224         {
 225                 BUG();
 226         }
 227         return &((VCHIQ_2835_ARM_STATE_T *)state->platform_state)->arm_state;
 228 }
 229
 230 void
 231 remote_event_signal(REMOTE_EVENT_T *event)
 232 {
 233         wmb();
 234
 235         event->fired = 1;
 236
 237         dsb(sy);         /* data barrier operation */
 238
 239         if (event->armed)
 240                 writel(0, g_regs + BELL2); /* trigger vc interrupt */
 241 }
 242
 243 VCHIQ_STATUS_T
 244 vchiq_prepare_bulk_data(VCHIQ_BULK_T *bulk, VCHI_MEM_HANDLE_T memhandle,
 245         void *offset, int size, int dir)
 246 {
 247         struct vchiq_pagelist_info *pagelistinfo;
 248
 249         WARN_ON(memhandle != VCHI_MEM_HANDLE_INVALID);
 250
 251         pagelistinfo = create_pagelist((char __user *)offset, size,
 252                                        (dir == VCHIQ_BULK_RECEIVE)
 253                                        ? PAGELIST_READ
 254                                        : PAGELIST_WRITE,
 255                                        current);
 256
 257         if (!pagelistinfo)
 258                 return VCHIQ_ERROR;
 259
 260         bulk->handle = memhandle;
 261         bulk->data = (void *)(unsigned long)pagelistinfo->dma_addr;
 262
 263         /*
 264          * Store the pagelistinfo address in remote_data,
 265          * which isn't used by the slave.
 266          */
 267         bulk->remote_data = pagelistinfo;
 268
 269         return VCHIQ_SUCCESS;
 270 }
 271
 272 void
 273 vchiq_complete_bulk(VCHIQ_BULK_T *bulk)
 274 {
 275         if (bulk && bulk->remote_data && bulk->actual)
 276                 free_pagelist((struct vchiq_pagelist_info *)bulk->remote_data,
 277                               bulk->actual);
 278 }
 279
 280 void
 281 vchiq_transfer_bulk(VCHIQ_BULK_T *bulk)
 282 {
 283         /*
 284          * This should only be called on the master (VideoCore) side, but
 285          * provide an implementation to avoid the need for ifdefery.
 286          */
 287         BUG();
 288 }
 289
 290 void
 291 vchiq_dump_platform_state(void *dump_context)
 292 {
 293         char buf[80];
 294         int len;
 295
 296         len = snprintf(buf, sizeof(buf),
 297                 "  Platform: 2835 (VC master)");
 298         vchiq_dump(dump_context, buf, len + 1);
 299 }
 300
 301 VCHIQ_STATUS_T
 302 vchiq_platform_suspend(VCHIQ_STATE_T *state)
 303 {
 304         return VCHIQ_ERROR;
 305 }
 306
 307 VCHIQ_STATUS_T
 308 vchiq_platform_resume(VCHIQ_STATE_T *state)
 309 {
 310         return VCHIQ_SUCCESS;
 311 }
 312
 313 void
 314 vchiq_platform_paused(VCHIQ_STATE_T *state)
 315 {
 316 }
 317
 318 void
 319 vchiq_platform_resumed(VCHIQ_STATE_T *state)
 320 {
 321 }
 322
 323 int
 324 vchiq_platform_videocore_wanted(VCHIQ_STATE_T *state)
 325 {
 326         return 1; // autosuspend not supported - videocore always wanted
 327 }
 328
 329 int
 330 vchiq_platform_use_suspend_timer(void)
 331 {
 332         return 0;
 333 }
 334 void
 335 vchiq_dump_platform_use_state(VCHIQ_STATE_T *state)
 336 {
 337         vchiq_log_info(vchiq_arm_log_level, "Suspend timer not in use");
 338 }
 339 void
 340 vchiq_platform_handle_timeout(VCHIQ_STATE_T *state)
 341 {
 342         (void)state;
 343 }
 344 /*
 345  * Local functions
 346  */
 347
 348 static irqreturn_t
 349 vchiq_doorbell_irq(int irq, void *dev_id)
 350 {
 351         VCHIQ_STATE_T *state = dev_id;
 352         irqreturn_t ret = IRQ_NONE;
 353         unsigned int status;
 354
 355         /* Read (and clear) the doorbell */
 356         status = readl(g_regs + BELL0);
 357
 358         if (status & 0x4) {  /* Was the doorbell rung? */
 359                 remote_event_pollall(state);
 360                 ret = IRQ_HANDLED;
 361         }
 362
 363         return ret;
 364 }
 365
 366 static void
 367 cleanup_pagelistinfo(struct vchiq_pagelist_info *pagelistinfo)
 368 {
 369         if (pagelistinfo->scatterlist_mapped) {
 370                 dma_unmap_sg(g_dev, pagelistinfo->scatterlist,
 371                              pagelistinfo->num_pages, pagelistinfo->dma_dir);
 372         }
 373
 374         if (pagelistinfo->pages_need_release) {
 375                 unsigned int i;
 376
 377                 for (i = 0; i < pagelistinfo->num_pages; i++)
 378                         put_page(pagelistinfo->pages[i]);
 379         }
 380
 381         dma_free_coherent(g_dev, pagelistinfo->pagelist_buffer_size,
 382                           pagelistinfo->pagelist, pagelistinfo->dma_addr);
 383 }
 384
 385 /* There is a potential problem with partial cache lines (pages?)
 386 ** at the ends of the block when reading. If the CPU accessed anything in
 387 ** the same line (page?) then it may have pulled old data into the cache,
 388 ** obscuring the new data underneath. We can solve this by transferring the
 389 ** partial cache lines separately, and allowing the ARM to copy into the
 390 ** cached area.
 391 */
 392
 393 static struct vchiq_pagelist_info *
 394 create_pagelist(char __user *buf, size_t count, unsigned short type,
 395                 struct task_struct *task)
 396 {
 397         PAGELIST_T *pagelist;
 398         struct vchiq_pagelist_info *pagelistinfo;
 399         struct page **pages;
 400         u32 *addrs;
 401         unsigned int num_pages, offset, i, k;
 402         int actual_pages;
 403         size_t pagelist_size;
 404         struct scatterlist *scatterlist, *sg;
 405         int dma_buffers;
 406         dma_addr_t dma_addr;
 407
 408         offset = ((unsigned int)(unsigned long)buf & (PAGE_SIZE - 1));
 409         num_pages = DIV_ROUND_UP(count + offset, PAGE_SIZE);
 410
 411         pagelist_size = sizeof(PAGELIST_T) +
 412                         (num_pages * sizeof(u32)) +
 413                         (num_pages * sizeof(pages[0]) +
 414                         (num_pages * sizeof(struct scatterlist))) +
 415                         sizeof(struct vchiq_pagelist_info);
 416
 417         /* Allocate enough storage to hold the page pointers and the page
 418         ** list
 419         */
 420         pagelist = dma_zalloc_coherent(g_dev,
 421                                        pagelist_size,
 422                                        &dma_addr,
 423                                        GFP_KERNEL);
 424
 425         vchiq_log_trace(vchiq_arm_log_level, "create_pagelist - %pK",
 426                         pagelist);
 427         if (!pagelist)
 428                 return NULL;
 429
 430         addrs           = pagelist->addrs;
 431         pages           = (struct page **)(addrs + num_pages);
 432         scatterlist     = (struct scatterlist *)(pages + num_pages);
 433         pagelistinfo    = (struct vchiq_pagelist_info *)
 434                           (scatterlist + num_pages);
 435
 436         pagelist->length = count;
 437         pagelist->type = type;
 438         pagelist->offset = offset;
 439
 440         /* Populate the fields of the pagelistinfo structure */
 441         pagelistinfo->pagelist = pagelist;
 442         pagelistinfo->pagelist_buffer_size = pagelist_size;
 443         pagelistinfo->dma_addr = dma_addr;
 444         pagelistinfo->dma_dir =  (type == PAGELIST_WRITE) ?
 445                                   DMA_TO_DEVICE : DMA_FROM_DEVICE;
 446         pagelistinfo->num_pages = num_pages;
 447         pagelistinfo->pages_need_release = 0;
 448         pagelistinfo->pages = pages;
 449         pagelistinfo->scatterlist = scatterlist;
 450         pagelistinfo->scatterlist_mapped = 0;
 451
 452         if (is_vmalloc_addr(buf)) {
 453                 unsigned long length = count;
 454                 unsigned int off = offset;
 455
 456                 for (actual_pages = 0; actual_pages < num_pages;
 457                      actual_pages++) {
 458                         struct page *pg = vmalloc_to_page(buf + (actual_pages *
 459                                                                  PAGE_SIZE));
 460                         size_t bytes = PAGE_SIZE - off;
 461
 462                         if (!pg) {
 463                                 cleanup_pagelistinfo(pagelistinfo);
 464                                 return NULL;
 465                         }
 466
 467                         if (bytes > length)
 468                                 bytes = length;
 469                         pages[actual_pages] = pg;
 470                         length -= bytes;
 471                         off = 0;
 472                 }
 473                 /* do not try and release vmalloc pages */
 474         } else {
 475                 down_read(&task->mm->mmap_sem);
 476                 actual_pages = get_user_pages(
 477                                           (unsigned long)buf & PAGE_MASK,
 478                                           num_pages,
 479                                           (type == PAGELIST_READ) ? FOLL_WRITE : 0,
 480                                           pages,
 481                                           NULL /*vmas */);
 482                 up_read(&task->mm->mmap_sem);
 483
 484                 if (actual_pages != num_pages) {
 485                         vchiq_log_info(vchiq_arm_log_level,
 486                                        "create_pagelist - only %d/%d pages locked",
 487                                        actual_pages,
 488                                        num_pages);
 489
 490                         /* This is probably due to the process being killed */
 491                         while (actual_pages > 0)
 492                         {
 493                                 actual_pages--;
 494                                 put_page(pages[actual_pages]);
 495                         }
 496                         cleanup_pagelistinfo(pagelistinfo);
 497                         return NULL;
 498                 }
 499                  /* release user pages */
 500                 pagelistinfo->pages_need_release = 1;
 501         }
 502
 503         /*
 504          * Initialize the scatterlist so that the magic cookie
 505          *  is filled if debugging is enabled
 506          */
 507         sg_init_table(scatterlist, num_pages);
 508         /* Now set the pages for each scatterlist */
 509         for (i = 0; i < num_pages; i++) {
 510                 unsigned int len = PAGE_SIZE - offset;
 511
 512                 if (len > count)
 513                         len = count;
 514                 sg_set_page(scatterlist + i, pages[i], len, offset);
 515                 offset = 0;
 516                 count -= len;
 517         }
 518
 519         dma_buffers = dma_map_sg(g_dev,
 520                                  scatterlist,
 521                                  num_pages,
 522                                  pagelistinfo->dma_dir);
 523
 524         if (dma_buffers == 0) {
 525                 cleanup_pagelistinfo(pagelistinfo);
 526                 return NULL;
 527         }
 528
 529         pagelistinfo->scatterlist_mapped = 1;
 530
 531         /* Combine adjacent blocks for performance */
 532         k = 0;
 533         for_each_sg(scatterlist, sg, dma_buffers, i) {
 534                 u32 len = sg_dma_len(sg);
 535                 u32 addr = sg_dma_address(sg);
 536
 537                 /* Note: addrs is the address + page_count - 1
 538                  * The firmware expects blocks after the first to be page-
 539                  * aligned and a multiple of the page size
 540                  */
 541                 WARN_ON(len == 0);
 542                 WARN_ON(i && (i != (dma_buffers - 1)) && (len & ~PAGE_MASK));
 543                 WARN_ON(i && (addr & ~PAGE_MASK));
 544                 if (k > 0 &&
 545                     ((addrs[k - 1] & PAGE_MASK) +
 546                      (((addrs[k - 1] & ~PAGE_MASK) + 1) << PAGE_SHIFT))
 547                     == (addr & PAGE_MASK))
 548                         addrs[k - 1] += ((len + PAGE_SIZE - 1) >> PAGE_SHIFT);
 549                 else
 550                         addrs[k++] = (addr & PAGE_MASK) |
 551                                 (((len + PAGE_SIZE - 1) >> PAGE_SHIFT) - 1);
 552         }
 553
 554         /* Partial cache lines (fragments) require special measures */
 555         if ((type == PAGELIST_READ) &&
 556                 ((pagelist->offset & (g_cache_line_size - 1)) ||
 557                 ((pagelist->offset + pagelist->length) &
 558                 (g_cache_line_size - 1)))) {
 559                 char *fragments;
 560
 561                 if (down_interruptible(&g_free_fragments_sema) != 0) {
 562                         cleanup_pagelistinfo(pagelistinfo);
 563                         return NULL;
 564                 }
 565
 566                 WARN_ON(g_free_fragments == NULL);
 567
 568                 down(&g_free_fragments_mutex);
 569                 fragments = g_free_fragments;
 570                 WARN_ON(fragments == NULL);
 571                 g_free_fragments = *(char **) g_free_fragments;
 572                 up(&g_free_fragments_mutex);
 573                 pagelist->type = PAGELIST_READ_WITH_FRAGMENTS +
 574                         (fragments - g_fragments_base) / g_fragments_size;
 575         }
 576
 577         return pagelistinfo;
 578 }
 579
 580 static void
 581 free_pagelist(struct vchiq_pagelist_info *pagelistinfo,
 582               int actual)
 583 {
 584         PAGELIST_T *pagelist   = pagelistinfo->pagelist;
 585         struct page **pages    = pagelistinfo->pages;
 586         unsigned int num_pages = pagelistinfo->num_pages;
 587
 588         vchiq_log_trace(vchiq_arm_log_level, "free_pagelist - %pK, %d",
 589                         pagelistinfo->pagelist, actual);
 590
 591         /*
 592          * NOTE: dma_unmap_sg must be called before the
 593          * cpu can touch any of the data/pages.
 594          */
 595         dma_unmap_sg(g_dev, pagelistinfo->scatterlist,
 596                      pagelistinfo->num_pages, pagelistinfo->dma_dir);
 597         pagelistinfo->scatterlist_mapped = 0;
 598
 599         /* Deal with any partial cache lines (fragments) */
 600         if (pagelist->type >= PAGELIST_READ_WITH_FRAGMENTS) {
 601                 char *fragments = g_fragments_base +
 602                         (pagelist->type - PAGELIST_READ_WITH_FRAGMENTS) *
 603                         g_fragments_size;
 604                 int head_bytes, tail_bytes;
 605
 606                 head_bytes = (g_cache_line_size - pagelist->offset) &
 607                         (g_cache_line_size - 1);
 608                 tail_bytes = (pagelist->offset + actual) &
 609                         (g_cache_line_size - 1);
 610
 611                 if ((actual >= 0) && (head_bytes != 0)) {
 612                         if (head_bytes > actual)
 613                                 head_bytes = actual;
 614
 615                         memcpy((char *)page_address(pages[0]) +
 616                                 pagelist->offset,
 617                                 fragments,
 618                                 head_bytes);
 619                 }
 620                 if ((actual >= 0) && (head_bytes < actual) &&
 621                         (tail_bytes != 0)) {
 622                         memcpy((char *)page_address(pages[num_pages - 1]) +
 623                                 ((pagelist->offset + actual) &
 624                                 (PAGE_SIZE - 1) & ~(g_cache_line_size - 1)),
 625                                 fragments + g_cache_line_size,
 626                                 tail_bytes);
 627                 }
 628
 629                 down(&g_free_fragments_mutex);
 630                 *(char **)fragments = g_free_fragments;
 631                 g_free_fragments = fragments;
 632                 up(&g_free_fragments_mutex);
 633                 up(&g_free_fragments_sema);
 634         }
 635
 636         /* Need to mark all the pages dirty. */
 637         if (pagelist->type != PAGELIST_WRITE &&
 638             pagelistinfo->pages_need_release) {
 639                 unsigned int i;
 640
 641                 for (i = 0; i < num_pages; i++)
 642                         set_page_dirty(pages[i]);
 643         }
 644
 645         cleanup_pagelistinfo(pagelistinfo);
 646 }