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/version.h>
  41 #include <linux/io.h>
  42 #include <linux/platform_device.h>
  43 #include <linux/uaccess.h>
  44 #include <linux/of.h>
  45 #include <asm/pgtable.h>
  46 #include <soc/bcm2835/raspberrypi-firmware.h>
  47
  48 #define TOTAL_SLOTS (VCHIQ_SLOT_ZERO_SLOTS + 2 * 32)
  49
  50 #include "vchiq_arm.h"
  51 #include "vchiq_connected.h"
  52 #include "vchiq_killable.h"
  53 #include "vchiq_pagelist.h"
  54
  55 #define MAX_FRAGMENTS (VCHIQ_NUM_CURRENT_BULKS * 2)
  56
  57 #define VCHIQ_PLATFORM_FRAGMENTS_OFFSET_IDX 0
  58 #define VCHIQ_PLATFORM_FRAGMENTS_COUNT_IDX  1
  59
  60 #define BELL0   0x00
  61 #define BELL2   0x08
  62
  63 typedef struct vchiq_2835_state_struct {
  64         int inited;
  65         VCHIQ_ARM_STATE_T arm_state;
  66 } VCHIQ_2835_ARM_STATE_T;
  67
  68 struct vchiq_pagelist_info {
  69         PAGELIST_T *pagelist;
  70         size_t pagelist_buffer_size;
  71         dma_addr_t dma_addr;
  72         enum dma_data_direction dma_dir;
  73         unsigned int num_pages;
  74         unsigned int pages_need_release;
  75         struct page **pages;
  76         struct scatterlist *scatterlist;
  77         unsigned int scatterlist_mapped;
  78 };
  79
  80 static void __iomem *g_regs;
  81 static unsigned int g_cache_line_size = sizeof(CACHE_LINE_SIZE);
  82 static unsigned int g_fragments_size;
  83 static char *g_fragments_base;
  84 static char *g_free_fragments;
  85 static struct semaphore g_free_fragments_sema;
  86 static struct device *g_dev;
  87
  88 extern int vchiq_arm_log_level;
  89
  90 static DEFINE_SEMAPHORE(g_free_fragments_mutex);
  91
  92 static irqreturn_t
  93 vchiq_doorbell_irq(int irq, void *dev_id);
  94
  95 static struct vchiq_pagelist_info *
  96 create_pagelist(char __user *buf, size_t count, unsigned short type,
  97                 struct task_struct *task);
  98
  99 static void
 100 free_pagelist(struct vchiq_pagelist_info *pagelistinfo,
 101               int actual);
 102
 103 int vchiq_platform_init(struct platform_device *pdev, VCHIQ_STATE_T *state)
 104 {
 105         struct device *dev = &pdev->dev;
 106         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 107         VCHIQ_SLOT_ZERO_T *vchiq_slot_zero;
 108         struct resource *res;
 109         void *slot_mem;
 110         dma_addr_t slot_phys;
 111         u32 channelbase;
 112         int slot_mem_size, frag_mem_size;
 113         int err, irq, i;
 114
 115         /*
 116          * VCHI messages between the CPU and firmware use
 117          * 32-bit bus addresses.
 118          */
 119         err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
 120
 121         if (err < 0)
 122                 return err;
 123
 124         (void)of_property_read_u32(dev->of_node, "cache-line-size",
 125                                    &g_cache_line_size);
 126         g_fragments_size = 2 * g_cache_line_size;
 127
 128         /* Allocate space for the channels in coherent memory */
 129         slot_mem_size = PAGE_ALIGN(TOTAL_SLOTS * VCHIQ_SLOT_SIZE);
 130         frag_mem_size = PAGE_ALIGN(g_fragments_size * MAX_FRAGMENTS);
 131
 132         slot_mem = dmam_alloc_coherent(dev, slot_mem_size + frag_mem_size,
 133                                        &slot_phys, GFP_KERNEL);
 134         if (!slot_mem) {
 135                 dev_err(dev, "could not allocate DMA memory\n");
 136                 return -ENOMEM;
 137         }
 138
 139         WARN_ON(((unsigned long)slot_mem & (PAGE_SIZE - 1)) != 0);
 140
 141         vchiq_slot_zero = vchiq_init_slots(slot_mem, slot_mem_size);
 142         if (!vchiq_slot_zero)
 143                 return -EINVAL;
 144
 145         vchiq_slot_zero->platform_data[VCHIQ_PLATFORM_FRAGMENTS_OFFSET_IDX] =
 146                 (int)slot_phys + slot_mem_size;
 147         vchiq_slot_zero->platform_data[VCHIQ_PLATFORM_FRAGMENTS_COUNT_IDX] =
 148                 MAX_FRAGMENTS;
 149
 150         g_fragments_base = (char *)slot_mem + slot_mem_size;
 151         slot_mem_size += frag_mem_size;
 152
 153         g_free_fragments = g_fragments_base;
 154         for (i = 0; i < (MAX_FRAGMENTS - 1); i++) {
 155                 *(char **)&g_fragments_base[i*g_fragments_size] =
 156                         &g_fragments_base[(i + 1)*g_fragments_size];
 157         }
 158         *(char **)&g_fragments_base[i * g_fragments_size] = NULL;
 159         sema_init(&g_free_fragments_sema, MAX_FRAGMENTS);
 160
 161         if (vchiq_init_state(state, vchiq_slot_zero, 0) != VCHIQ_SUCCESS)
 162                 return -EINVAL;
 163
 164         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 165         g_regs = devm_ioremap_resource(&pdev->dev, res);
 166         if (IS_ERR(g_regs))
 167                 return PTR_ERR(g_regs);
 168
 169         irq = platform_get_irq(pdev, 0);
 170         if (irq <= 0) {
 171                 dev_err(dev, "failed to get IRQ\n");
 172                 return irq;
 173         }
 174
 175         err = devm_request_irq(dev, irq, vchiq_doorbell_irq, IRQF_IRQPOLL,
 176                                "VCHIQ doorbell", state);
 177         if (err) {
 178                 dev_err(dev, "failed to register irq=%d\n", irq);
 179                 return err;
 180         }
 181
 182         /* Send the base address of the slots to VideoCore */
 183         channelbase = slot_phys;
 184         err = rpi_firmware_property(fw, RPI_FIRMWARE_VCHIQ_INIT,
 185                                     &channelbase, sizeof(channelbase));
 186         if (err || channelbase) {
 187                 dev_err(dev, "failed to set channelbase\n");
 188                 return err ? : -ENXIO;
 189         }
 190
 191         g_dev = dev;
 192         vchiq_log_info(vchiq_arm_log_level,
 193                 "vchiq_init - done (slots %pK, phys %pad)",
 194                 vchiq_slot_zero, &slot_phys);
 195
 196         vchiq_call_connected_callbacks();
 197
 198         return 0;
 199 }
 200
 201 VCHIQ_STATUS_T
 202 vchiq_platform_init_state(VCHIQ_STATE_T *state)
 203 {
 204         VCHIQ_STATUS_T status = VCHIQ_SUCCESS;
 205         state->platform_state = kzalloc(sizeof(VCHIQ_2835_ARM_STATE_T), GFP_KERNEL);
 206         ((VCHIQ_2835_ARM_STATE_T *)state->platform_state)->inited = 1;
 207         status = vchiq_arm_init_state(state, &((VCHIQ_2835_ARM_STATE_T *)state->platform_state)->arm_state);
 208         if (status != VCHIQ_SUCCESS)
 209         {
 210                 ((VCHIQ_2835_ARM_STATE_T *)state->platform_state)->inited = 0;
 211         }
 212         return status;
 213 }
 214
 215 VCHIQ_ARM_STATE_T*
 216 vchiq_platform_get_arm_state(VCHIQ_STATE_T *state)
 217 {
 218         if (!((VCHIQ_2835_ARM_STATE_T *)state->platform_state)->inited)
 219         {
 220                 BUG();
 221         }
 222         return &((VCHIQ_2835_ARM_STATE_T *)state->platform_state)->arm_state;
 223 }
 224
 225 void
 226 remote_event_signal(REMOTE_EVENT_T *event)
 227 {
 228         wmb();
 229
 230         event->fired = 1;
 231
 232         dsb(sy);         /* data barrier operation */
 233
 234         if (event->armed)
 235                 writel(0, g_regs + BELL2); /* trigger vc interrupt */
 236 }
 237
 238 VCHIQ_STATUS_T
 239 vchiq_prepare_bulk_data(VCHIQ_BULK_T *bulk, VCHI_MEM_HANDLE_T memhandle,
 240         void *offset, int size, int dir)
 241 {
 242         struct vchiq_pagelist_info *pagelistinfo;
 243
 244         WARN_ON(memhandle != VCHI_MEM_HANDLE_INVALID);
 245
 246         pagelistinfo = create_pagelist((char __user *)offset, size,
 247                                        (dir == VCHIQ_BULK_RECEIVE)
 248                                        ? PAGELIST_READ
 249                                        : PAGELIST_WRITE,
 250                                        current);
 251
 252         if (!pagelistinfo)
 253                 return VCHIQ_ERROR;
 254
 255         bulk->handle = memhandle;
 256         bulk->data = (void *)(unsigned long)pagelistinfo->dma_addr;
 257
 258         /*
 259          * Store the pagelistinfo address in remote_data,
 260          * which isn't used by the slave.
 261          */
 262         bulk->remote_data = pagelistinfo;
 263
 264         return VCHIQ_SUCCESS;
 265 }
 266
 267 void
 268 vchiq_complete_bulk(VCHIQ_BULK_T *bulk)
 269 {
 270         if (bulk && bulk->remote_data && bulk->actual)
 271                 free_pagelist((struct vchiq_pagelist_info *)bulk->remote_data,
 272                               bulk->actual);
 273 }
 274
 275 void
 276 vchiq_transfer_bulk(VCHIQ_BULK_T *bulk)
 277 {
 278         /*
 279          * This should only be called on the master (VideoCore) side, but
 280          * provide an implementation to avoid the need for ifdefery.
 281          */
 282         BUG();
 283 }
 284
 285 void
 286 vchiq_dump_platform_state(void *dump_context)
 287 {
 288         char buf[80];
 289         int len;
 290         len = snprintf(buf, sizeof(buf),
 291                 "  Platform: 2835 (VC master)");
 292         vchiq_dump(dump_context, buf, len + 1);
 293 }
 294
 295 VCHIQ_STATUS_T
 296 vchiq_platform_suspend(VCHIQ_STATE_T *state)
 297 {
 298         return VCHIQ_ERROR;
 299 }
 300
 301 VCHIQ_STATUS_T
 302 vchiq_platform_resume(VCHIQ_STATE_T *state)
 303 {
 304         return VCHIQ_SUCCESS;
 305 }
 306
 307 void
 308 vchiq_platform_paused(VCHIQ_STATE_T *state)
 309 {
 310 }
 311
 312 void
 313 vchiq_platform_resumed(VCHIQ_STATE_T *state)
 314 {
 315 }
 316
 317 int
 318 vchiq_platform_videocore_wanted(VCHIQ_STATE_T *state)
 319 {
 320         return 1; // autosuspend not supported - videocore always wanted
 321 }
 322
 323 int
 324 vchiq_platform_use_suspend_timer(void)
 325 {
 326         return 0;
 327 }
 328 void
 329 vchiq_dump_platform_use_state(VCHIQ_STATE_T *state)
 330 {
 331         vchiq_log_info(vchiq_arm_log_level, "Suspend timer not in use");
 332 }
 333 void
 334 vchiq_platform_handle_timeout(VCHIQ_STATE_T *state)
 335 {
 336         (void)state;
 337 }
 338 /*
 339  * Local functions
 340  */
 341
 342 static irqreturn_t
 343 vchiq_doorbell_irq(int irq, void *dev_id)
 344 {
 345         VCHIQ_STATE_T *state = dev_id;
 346         irqreturn_t ret = IRQ_NONE;
 347         unsigned int status;
 348
 349         /* Read (and clear) the doorbell */
 350         status = readl(g_regs + BELL0);
 351
 352         if (status & 0x4) {  /* Was the doorbell rung? */
 353                 remote_event_pollall(state);
 354                 ret = IRQ_HANDLED;
 355         }
 356
 357         return ret;
 358 }
 359
 360 static void
 361 cleaup_pagelistinfo(struct vchiq_pagelist_info *pagelistinfo)
 362 {
 363         if (pagelistinfo->scatterlist_mapped) {
 364                 dma_unmap_sg(g_dev, pagelistinfo->scatterlist,
 365                              pagelistinfo->num_pages, pagelistinfo->dma_dir);
 366         }
 367
 368         if (pagelistinfo->pages_need_release) {
 369                 unsigned int i;
 370
 371                 for (i = 0; i < pagelistinfo->num_pages; i++)
 372                         put_page(pagelistinfo->pages[i]);
 373         }
 374
 375         dma_free_coherent(g_dev, pagelistinfo->pagelist_buffer_size,
 376                           pagelistinfo->pagelist, pagelistinfo->dma_addr);
 377 }
 378
 379 /* There is a potential problem with partial cache lines (pages?)
 380 ** at the ends of the block when reading. If the CPU accessed anything in
 381 ** the same line (page?) then it may have pulled old data into the cache,
 382 ** obscuring the new data underneath. We can solve this by transferring the
 383 ** partial cache lines separately, and allowing the ARM to copy into the
 384 ** cached area.
 385 */
 386
 387 static struct vchiq_pagelist_info *
 388 create_pagelist(char __user *buf, size_t count, unsigned short type,
 389                 struct task_struct *task)
 390 {
 391         PAGELIST_T *pagelist;
 392         struct vchiq_pagelist_info *pagelistinfo;
 393         struct page **pages;
 394         u32 *addrs;
 395         unsigned int num_pages, offset, i, k;
 396         int actual_pages;
 397         size_t pagelist_size;
 398         struct scatterlist *scatterlist, *sg;
 399         int dma_buffers;
 400         dma_addr_t dma_addr;
 401
 402         offset = ((unsigned int)(unsigned long)buf & (PAGE_SIZE - 1));
 403         num_pages = (count + offset + PAGE_SIZE - 1) / PAGE_SIZE;
 404
 405         pagelist_size = sizeof(PAGELIST_T) +
 406                         (num_pages * sizeof(u32)) +
 407                         (num_pages * sizeof(pages[0]) +
 408                         (num_pages * sizeof(struct scatterlist))) +
 409                         sizeof(struct vchiq_pagelist_info);
 410
 411         /* Allocate enough storage to hold the page pointers and the page
 412         ** list
 413         */
 414         pagelist = dma_zalloc_coherent(g_dev,
 415                                        pagelist_size,
 416                                        &dma_addr,
 417                                        GFP_KERNEL);
 418
 419         vchiq_log_trace(vchiq_arm_log_level, "create_pagelist - %pK",
 420                         pagelist);
 421         if (!pagelist)
 422                 return NULL;
 423
 424         addrs           = pagelist->addrs;
 425         pages           = (struct page **)(addrs + num_pages);
 426         scatterlist     = (struct scatterlist *)(pages + num_pages);
 427         pagelistinfo    = (struct vchiq_pagelist_info *)
 428                           (scatterlist + num_pages);
 429
 430         pagelist->length = count;
 431         pagelist->type = type;
 432         pagelist->offset = offset;
 433
 434         /* Populate the fields of the pagelistinfo structure */
 435         pagelistinfo->pagelist = pagelist;
 436         pagelistinfo->pagelist_buffer_size = pagelist_size;
 437         pagelistinfo->dma_addr = dma_addr;
 438         pagelistinfo->dma_dir =  (type == PAGELIST_WRITE) ?
 439                                   DMA_TO_DEVICE : DMA_FROM_DEVICE;
 440         pagelistinfo->num_pages = num_pages;
 441         pagelistinfo->pages_need_release = 0;
 442         pagelistinfo->pages = pages;
 443         pagelistinfo->scatterlist = scatterlist;
 444         pagelistinfo->scatterlist_mapped = 0;
 445
 446         if (is_vmalloc_addr(buf)) {
 447                 unsigned long length = count;
 448                 unsigned int off = offset;
 449
 450                 for (actual_pages = 0; actual_pages < num_pages;
 451                      actual_pages++) {
 452                         struct page *pg = vmalloc_to_page(buf + (actual_pages *
 453                                                                  PAGE_SIZE));
 454                         size_t bytes = PAGE_SIZE - off;
 455
 456                         if (bytes > length)
 457                                 bytes = length;
 458                         pages[actual_pages] = pg;
 459                         length -= bytes;
 460                         off = 0;
 461                 }
 462                 /* do not try and release vmalloc pages */
 463         } else {
 464                 down_read(&task->mm->mmap_sem);
 465                 actual_pages = get_user_pages(
 466                                           (unsigned long)buf & ~(PAGE_SIZE - 1),
 467                                           num_pages,
 468                                           (type == PAGELIST_READ) ? FOLL_WRITE : 0,
 469                                           pages,
 470                                           NULL /*vmas */);
 471                 up_read(&task->mm->mmap_sem);
 472
 473                 if (actual_pages != num_pages) {
 474                         vchiq_log_info(vchiq_arm_log_level,
 475                                        "create_pagelist - only %d/%d pages locked",
 476                                        actual_pages,
 477                                        num_pages);
 478
 479                         /* This is probably due to the process being killed */
 480                         while (actual_pages > 0)
 481                         {
 482                                 actual_pages--;
 483                                 put_page(pages[actual_pages]);
 484                         }
 485                         cleaup_pagelistinfo(pagelistinfo);
 486                         return NULL;
 487                 }
 488                  /* release user pages */
 489                 pagelistinfo->pages_need_release = 1;
 490         }
 491
 492         /*
 493          * Initialize the scatterlist so that the magic cookie
 494          *  is filled if debugging is enabled
 495          */
 496         sg_init_table(scatterlist, num_pages);
 497         /* Now set the pages for each scatterlist */
 498         for (i = 0; i < num_pages; i++)
 499                 sg_set_page(scatterlist + i, pages[i], PAGE_SIZE, 0);
 500
 501         dma_buffers = dma_map_sg(g_dev,
 502                                  scatterlist,
 503                                  num_pages,
 504                                  pagelistinfo->dma_dir);
 505
 506         if (dma_buffers == 0) {
 507                 cleaup_pagelistinfo(pagelistinfo);
 508                 return NULL;
 509         }
 510
 511         pagelistinfo->scatterlist_mapped = 1;
 512
 513         /* Combine adjacent blocks for performance */
 514         k = 0;
 515         for_each_sg(scatterlist, sg, dma_buffers, i) {
 516                 u32 len = sg_dma_len(sg);
 517                 u32 addr = sg_dma_address(sg);
 518
 519                 /* Note: addrs is the address + page_count - 1
 520                  * The firmware expects the block to be page
 521                  * aligned and a multiple of the page size
 522                  */
 523                 WARN_ON(len == 0);
 524                 WARN_ON(len & ~PAGE_MASK);
 525                 WARN_ON(addr & ~PAGE_MASK);
 526                 if (k > 0 &&
 527                     ((addrs[k - 1] & PAGE_MASK) |
 528                         ((addrs[k - 1] & ~PAGE_MASK) + 1) << PAGE_SHIFT)
 529                     == addr) {
 530                         addrs[k - 1] += (len >> PAGE_SHIFT);
 531                 } else {
 532                         addrs[k++] = addr | ((len >> PAGE_SHIFT) - 1);
 533                 }
 534         }
 535
 536         /* Partial cache lines (fragments) require special measures */
 537         if ((type == PAGELIST_READ) &&
 538                 ((pagelist->offset & (g_cache_line_size - 1)) ||
 539                 ((pagelist->offset + pagelist->length) &
 540                 (g_cache_line_size - 1)))) {
 541                 char *fragments;
 542
 543                 if (down_interruptible(&g_free_fragments_sema) != 0) {
 544                         cleaup_pagelistinfo(pagelistinfo);
 545                         return NULL;
 546                 }
 547
 548                 WARN_ON(g_free_fragments == NULL);
 549
 550                 down(&g_free_fragments_mutex);
 551                 fragments = g_free_fragments;
 552                 WARN_ON(fragments == NULL);
 553                 g_free_fragments = *(char **) g_free_fragments;
 554                 up(&g_free_fragments_mutex);
 555                 pagelist->type = PAGELIST_READ_WITH_FRAGMENTS +
 556                         (fragments - g_fragments_base) / g_fragments_size;
 557         }
 558
 559         return pagelistinfo;
 560 }
 561
 562 static void
 563 free_pagelist(struct vchiq_pagelist_info *pagelistinfo,
 564               int actual)
 565 {
 566         unsigned int i;
 567         PAGELIST_T *pagelist   = pagelistinfo->pagelist;
 568         struct page **pages    = pagelistinfo->pages;
 569         unsigned int num_pages = pagelistinfo->num_pages;
 570
 571         vchiq_log_trace(vchiq_arm_log_level, "free_pagelist - %pK, %d",
 572                         pagelistinfo->pagelist, actual);
 573
 574         /*
 575          * NOTE: dma_unmap_sg must be called before the
 576          * cpu can touch any of the data/pages.
 577          */
 578         dma_unmap_sg(g_dev, pagelistinfo->scatterlist,
 579                      pagelistinfo->num_pages, pagelistinfo->dma_dir);
 580         pagelistinfo->scatterlist_mapped = 0;
 581
 582         /* Deal with any partial cache lines (fragments) */
 583         if (pagelist->type >= PAGELIST_READ_WITH_FRAGMENTS) {
 584                 char *fragments = g_fragments_base +
 585                         (pagelist->type - PAGELIST_READ_WITH_FRAGMENTS) *
 586                         g_fragments_size;
 587                 int head_bytes, tail_bytes;
 588                 head_bytes = (g_cache_line_size - pagelist->offset) &
 589                         (g_cache_line_size - 1);
 590                 tail_bytes = (pagelist->offset + actual) &
 591                         (g_cache_line_size - 1);
 592
 593                 if ((actual >= 0) && (head_bytes != 0)) {
 594                         if (head_bytes > actual)
 595                                 head_bytes = actual;
 596
 597                         memcpy((char *)page_address(pages[0]) +
 598                                 pagelist->offset,
 599                                 fragments,
 600                                 head_bytes);
 601                 }
 602                 if ((actual >= 0) && (head_bytes < actual) &&
 603                         (tail_bytes != 0)) {
 604                         memcpy((char *)page_address(pages[num_pages - 1]) +
 605                                 ((pagelist->offset + actual) &
 606                                 (PAGE_SIZE - 1) & ~(g_cache_line_size - 1)),
 607                                 fragments + g_cache_line_size,
 608                                 tail_bytes);
 609                 }
 610
 611                 down(&g_free_fragments_mutex);
 612                 *(char **)fragments = g_free_fragments;
 613                 g_free_fragments = fragments;
 614                 up(&g_free_fragments_mutex);
 615                 up(&g_free_fragments_sema);
 616         }
 617
 618         /* Need to mark all the pages dirty. */
 619         if (pagelist->type != PAGELIST_WRITE &&
 620             pagelistinfo->pages_need_release) {
 621                 for (i = 0; i < num_pages; i++)
 622                         set_page_dirty(pages[i]);
 623         }
 624
 625         cleaup_pagelistinfo(pagelistinfo);
 626 }