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         slot_mem_size += frag_mem_size;
 157
 158         g_free_fragments = g_fragments_base;
 159         for (i = 0; i < (MAX_FRAGMENTS - 1); i++) {
 160                 *(char **)&g_fragments_base[i*g_fragments_size] =
 161                         &g_fragments_base[(i + 1)*g_fragments_size];
 162         }
 163         *(char **)&g_fragments_base[i * g_fragments_size] = NULL;
 164         sema_init(&g_free_fragments_sema, MAX_FRAGMENTS);
 165
 166         if (vchiq_init_state(state, vchiq_slot_zero, 0) != VCHIQ_SUCCESS)
 167                 return -EINVAL;
 168
 169         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 170         g_regs = devm_ioremap_resource(&pdev->dev, res);
 171         if (IS_ERR(g_regs))
 172                 return PTR_ERR(g_regs);
 173
 174         irq = platform_get_irq(pdev, 0);
 175         if (irq <= 0) {
 176                 dev_err(dev, "failed to get IRQ\n");
 177                 return irq;
 178         }
 179
 180         err = devm_request_irq(dev, irq, vchiq_doorbell_irq, IRQF_IRQPOLL,
 181                                "VCHIQ doorbell", state);
 182         if (err) {
 183                 dev_err(dev, "failed to register irq=%d\n", irq);
 184                 return err;
 185         }
 186
 187         /* Send the base address of the slots to VideoCore */
 188         channelbase = slot_phys;
 189         err = rpi_firmware_property(fw, RPI_FIRMWARE_VCHIQ_INIT,
 190                                     &channelbase, sizeof(channelbase));
 191         if (err || channelbase) {
 192                 dev_err(dev, "failed to set channelbase\n");
 193                 return err ? : -ENXIO;
 194         }
 195
 196         g_dev = dev;
 197         vchiq_log_info(vchiq_arm_log_level,
 198                 "vchiq_init - done (slots %pK, phys %pad)",
 199                 vchiq_slot_zero, &slot_phys);
 200
 201         vchiq_call_connected_callbacks();
 202
 203         return 0;
 204 }
 205
 206 VCHIQ_STATUS_T
 207 vchiq_platform_init_state(VCHIQ_STATE_T *state)
 208 {
 209         VCHIQ_STATUS_T status = VCHIQ_SUCCESS;
 210
 211         state->platform_state = kzalloc(sizeof(VCHIQ_2835_ARM_STATE_T), GFP_KERNEL);
 212         ((VCHIQ_2835_ARM_STATE_T *)state->platform_state)->inited = 1;
 213         status = vchiq_arm_init_state(state, &((VCHIQ_2835_ARM_STATE_T *)state->platform_state)->arm_state);
 214         if (status != VCHIQ_SUCCESS)
 215         {
 216                 ((VCHIQ_2835_ARM_STATE_T *)state->platform_state)->inited = 0;
 217         }
 218         return status;
 219 }
 220
 221 VCHIQ_ARM_STATE_T*
 222 vchiq_platform_get_arm_state(VCHIQ_STATE_T *state)
 223 {
 224         if (!((VCHIQ_2835_ARM_STATE_T *)state->platform_state)->inited)
 225         {
 226                 BUG();
 227         }
 228         return &((VCHIQ_2835_ARM_STATE_T *)state->platform_state)->arm_state;
 229 }
 230
 231 void
 232 remote_event_signal(REMOTE_EVENT_T *event)
 233 {
 234         wmb();
 235
 236         event->fired = 1;
 237
 238         dsb(sy);         /* data barrier operation */
 239
 240         if (event->armed)
 241                 writel(0, g_regs + BELL2); /* trigger vc interrupt */
 242 }
 243
 244 VCHIQ_STATUS_T
 245 vchiq_prepare_bulk_data(VCHIQ_BULK_T *bulk, VCHI_MEM_HANDLE_T memhandle,
 246         void *offset, int size, int dir)
 247 {
 248         struct vchiq_pagelist_info *pagelistinfo;
 249
 250         WARN_ON(memhandle != VCHI_MEM_HANDLE_INVALID);
 251
 252         pagelistinfo = create_pagelist((char __user *)offset, size,
 253                                        (dir == VCHIQ_BULK_RECEIVE)
 254                                        ? PAGELIST_READ
 255                                        : PAGELIST_WRITE,
 256                                        current);
 257
 258         if (!pagelistinfo)
 259                 return VCHIQ_ERROR;
 260
 261         bulk->handle = memhandle;
 262         bulk->data = (void *)(unsigned long)pagelistinfo->dma_addr;
 263
 264         /*
 265          * Store the pagelistinfo address in remote_data,
 266          * which isn't used by the slave.
 267          */
 268         bulk->remote_data = pagelistinfo;
 269
 270         return VCHIQ_SUCCESS;
 271 }
 272
 273 void
 274 vchiq_complete_bulk(VCHIQ_BULK_T *bulk)
 275 {
 276         if (bulk && bulk->remote_data && bulk->actual)
 277                 free_pagelist((struct vchiq_pagelist_info *)bulk->remote_data,
 278                               bulk->actual);
 279 }
 280
 281 void
 282 vchiq_transfer_bulk(VCHIQ_BULK_T *bulk)
 283 {
 284         /*
 285          * This should only be called on the master (VideoCore) side, but
 286          * provide an implementation to avoid the need for ifdefery.
 287          */
 288         BUG();
 289 }
 290
 291 void
 292 vchiq_dump_platform_state(void *dump_context)
 293 {
 294         char buf[80];
 295         int len;
 296
 297         len = snprintf(buf, sizeof(buf),
 298                 "  Platform: 2835 (VC master)");
 299         vchiq_dump(dump_context, buf, len + 1);
 300 }
 301
 302 VCHIQ_STATUS_T
 303 vchiq_platform_suspend(VCHIQ_STATE_T *state)
 304 {
 305         return VCHIQ_ERROR;
 306 }
 307
 308 VCHIQ_STATUS_T
 309 vchiq_platform_resume(VCHIQ_STATE_T *state)
 310 {
 311         return VCHIQ_SUCCESS;
 312 }
 313
 314 void
 315 vchiq_platform_paused(VCHIQ_STATE_T *state)
 316 {
 317 }
 318
 319 void
 320 vchiq_platform_resumed(VCHIQ_STATE_T *state)
 321 {
 322 }
 323
 324 int
 325 vchiq_platform_videocore_wanted(VCHIQ_STATE_T *state)
 326 {
 327         return 1; // autosuspend not supported - videocore always wanted
 328 }
 329
 330 int
 331 vchiq_platform_use_suspend_timer(void)
 332 {
 333         return 0;
 334 }
 335 void
 336 vchiq_dump_platform_use_state(VCHIQ_STATE_T *state)
 337 {
 338         vchiq_log_info(vchiq_arm_log_level, "Suspend timer not in use");
 339 }
 340 void
 341 vchiq_platform_handle_timeout(VCHIQ_STATE_T *state)
 342 {
 343         (void)state;
 344 }
 345 /*
 346  * Local functions
 347  */
 348
 349 static irqreturn_t
 350 vchiq_doorbell_irq(int irq, void *dev_id)
 351 {
 352         VCHIQ_STATE_T *state = dev_id;
 353         irqreturn_t ret = IRQ_NONE;
 354         unsigned int status;
 355
 356         /* Read (and clear) the doorbell */
 357         status = readl(g_regs + BELL0);
 358
 359         if (status & 0x4) {  /* Was the doorbell rung? */
 360                 remote_event_pollall(state);
 361                 ret = IRQ_HANDLED;
 362         }
 363
 364         return ret;
 365 }
 366
 367 static void
 368 cleaup_pagelistinfo(struct vchiq_pagelist_info *pagelistinfo)
 369 {
 370         if (pagelistinfo->scatterlist_mapped) {
 371                 dma_unmap_sg(g_dev, pagelistinfo->scatterlist,
 372                              pagelistinfo->num_pages, pagelistinfo->dma_dir);
 373         }
 374
 375         if (pagelistinfo->pages_need_release) {
 376                 unsigned int i;
 377
 378                 for (i = 0; i < pagelistinfo->num_pages; i++)
 379                         put_page(pagelistinfo->pages[i]);
 380         }
 381
 382         dma_free_coherent(g_dev, pagelistinfo->pagelist_buffer_size,
 383                           pagelistinfo->pagelist, pagelistinfo->dma_addr);
 384 }
 385
 386 /* There is a potential problem with partial cache lines (pages?)
 387 ** at the ends of the block when reading. If the CPU accessed anything in
 388 ** the same line (page?) then it may have pulled old data into the cache,
 389 ** obscuring the new data underneath. We can solve this by transferring the
 390 ** partial cache lines separately, and allowing the ARM to copy into the
 391 ** cached area.
 392 */
 393
 394 static struct vchiq_pagelist_info *
 395 create_pagelist(char __user *buf, size_t count, unsigned short type,
 396                 struct task_struct *task)
 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, "create_pagelist - %pK",
 427                         pagelist);
 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 (bytes > length)
 464                                 bytes = length;
 465                         pages[actual_pages] = pg;
 466                         length -= bytes;
 467                         off = 0;
 468                 }
 469                 /* do not try and release vmalloc pages */
 470         } else {
 471                 down_read(&task->mm->mmap_sem);
 472                 actual_pages = get_user_pages(
 473                                           (unsigned long)buf & ~(PAGE_SIZE - 1),
 474                                           num_pages,
 475                                           (type == PAGELIST_READ) ? FOLL_WRITE : 0,
 476                                           pages,
 477                                           NULL /*vmas */);
 478                 up_read(&task->mm->mmap_sem);
 479
 480                 if (actual_pages != num_pages) {
 481                         vchiq_log_info(vchiq_arm_log_level,
 482                                        "create_pagelist - only %d/%d pages locked",
 483                                        actual_pages,
 484                                        num_pages);
 485
 486                         /* This is probably due to the process being killed */
 487                         while (actual_pages > 0)
 488                         {
 489                                 actual_pages--;
 490                                 put_page(pages[actual_pages]);
 491                         }
 492                         cleaup_pagelistinfo(pagelistinfo);
 493                         return NULL;
 494                 }
 495                  /* release user pages */
 496                 pagelistinfo->pages_need_release = 1;
 497         }
 498
 499         /*
 500          * Initialize the scatterlist so that the magic cookie
 501          *  is filled if debugging is enabled
 502          */
 503         sg_init_table(scatterlist, num_pages);
 504         /* Now set the pages for each scatterlist */
 505         for (i = 0; i < num_pages; i++) {
 506                 unsigned int len = PAGE_SIZE - offset;
 507
 508                 if (len > count)
 509                         len = count;
 510                 sg_set_page(scatterlist + i, pages[i], len, offset);
 511                 offset = 0;
 512                 count -= len;
 513         }
 514
 515         dma_buffers = dma_map_sg(g_dev,
 516                                  scatterlist,
 517                                  num_pages,
 518                                  pagelistinfo->dma_dir);
 519
 520         if (dma_buffers == 0) {
 521                 cleaup_pagelistinfo(pagelistinfo);
 522                 return NULL;
 523         }
 524
 525         pagelistinfo->scatterlist_mapped = 1;
 526
 527         /* Combine adjacent blocks for performance */
 528         k = 0;
 529         for_each_sg(scatterlist, sg, dma_buffers, i) {
 530                 u32 len = sg_dma_len(sg);
 531                 u32 addr = sg_dma_address(sg);
 532
 533                 /* Note: addrs is the address + page_count - 1
 534                  * The firmware expects blocks after the first to be page-
 535                  * aligned and a multiple of the page size
 536                  */
 537                 WARN_ON(len == 0);
 538                 WARN_ON(i && (i != (dma_buffers - 1)) && (len & ~PAGE_MASK));
 539                 WARN_ON(i && (addr & ~PAGE_MASK));
 540                 if (k > 0 &&
 541                     ((addrs[k - 1] & PAGE_MASK) +
 542                      (((addrs[k - 1] & ~PAGE_MASK) + 1) << PAGE_SHIFT))
 543                     == (addr & PAGE_MASK))
 544                         addrs[k - 1] += ((len + PAGE_SIZE - 1) >> PAGE_SHIFT);
 545                 else
 546                         addrs[k++] = (addr & PAGE_MASK) |
 547                                 (((len + PAGE_SIZE - 1) >> PAGE_SHIFT) - 1);
 548         }
 549
 550         /* Partial cache lines (fragments) require special measures */
 551         if ((type == PAGELIST_READ) &&
 552                 ((pagelist->offset & (g_cache_line_size - 1)) ||
 553                 ((pagelist->offset + pagelist->length) &
 554                 (g_cache_line_size - 1)))) {
 555                 char *fragments;
 556
 557                 if (down_interruptible(&g_free_fragments_sema) != 0) {
 558                         cleaup_pagelistinfo(pagelistinfo);
 559                         return NULL;
 560                 }
 561
 562                 WARN_ON(g_free_fragments == NULL);
 563
 564                 down(&g_free_fragments_mutex);
 565                 fragments = g_free_fragments;
 566                 WARN_ON(fragments == NULL);
 567                 g_free_fragments = *(char **) g_free_fragments;
 568                 up(&g_free_fragments_mutex);
 569                 pagelist->type = PAGELIST_READ_WITH_FRAGMENTS +
 570                         (fragments - g_fragments_base) / g_fragments_size;
 571         }
 572
 573         return pagelistinfo;
 574 }
 575
 576 static void
 577 free_pagelist(struct vchiq_pagelist_info *pagelistinfo,
 578               int actual)
 579 {
 580         unsigned int i;
 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 *)page_address(pages[0]) +
 613                                 pagelist->offset,
 614                                 fragments,
 615                                 head_bytes);
 616                 }
 617                 if ((actual >= 0) && (head_bytes < actual) &&
 618                         (tail_bytes != 0)) {
 619                         memcpy((char *)page_address(pages[num_pages - 1]) +
 620                                 ((pagelist->offset + actual) &
 621                                 (PAGE_SIZE - 1) & ~(g_cache_line_size - 1)),
 622                                 fragments + g_cache_line_size,
 623                                 tail_bytes);
 624                 }
 625
 626                 down(&g_free_fragments_mutex);
 627                 *(char **)fragments = g_free_fragments;
 628                 g_free_fragments = fragments;
 629                 up(&g_free_fragments_mutex);
 630                 up(&g_free_fragments_sema);
 631         }
 632
 633         /* Need to mark all the pages dirty. */
 634         if (pagelist->type != PAGELIST_WRITE &&
 635             pagelistinfo->pages_need_release) {
 636                 for (i = 0; i < num_pages; i++)
 637                         set_page_dirty(pages[i]);
 638         }
 639
 640         cleaup_pagelistinfo(pagelistinfo);
 641 }