sound/pci/emu10k1/memory.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   4  *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
   5  *
   6  *  EMU10K1 memory page allocation (PTB area)
   7  */
   8
   9 #include <linux/pci.h>
  10 #include <linux/gfp.h>
  11 #include <linux/time.h>
  12 #include <linux/mutex.h>
  13 #include <linux/export.h>
  14
  15 #include <sound/core.h>
  16 #include <sound/emu10k1.h>
  17
  18 /* page arguments of these two macros are Emu page (4096 bytes), not like
  19  * aligned pages in others
  20  */
  21 #define __set_ptb_entry(emu,page,addr) \
  22         (((__le32 *)(emu)->ptb_pages.area)[page] = \
  23          cpu_to_le32(((addr) << (emu->address_mode)) | (page)))
  24 #define __get_ptb_entry(emu, page) \
  25         (le32_to_cpu(((__le32 *)(emu)->ptb_pages.area)[page]))
  26
  27 #define UNIT_PAGES              (PAGE_SIZE / EMUPAGESIZE)
  28 #define MAX_ALIGN_PAGES0                (MAXPAGES0 / UNIT_PAGES)
  29 #define MAX_ALIGN_PAGES1                (MAXPAGES1 / UNIT_PAGES)
  30 /* get aligned page from offset address */
  31 #define get_aligned_page(offset)        ((offset) >> PAGE_SHIFT)
  32 /* get offset address from aligned page */
  33 #define aligned_page_offset(page)       ((page) << PAGE_SHIFT)
  34
  35 #if PAGE_SIZE == EMUPAGESIZE && !IS_ENABLED(CONFIG_DYNAMIC_DEBUG)
  36 /* fill PTB entrie(s) corresponding to page with addr */
  37 #define set_ptb_entry(emu,page,addr)    __set_ptb_entry(emu,page,addr)
  38 /* fill PTB entrie(s) corresponding to page with silence pointer */
  39 #define set_silent_ptb(emu,page)        __set_ptb_entry(emu,page,emu->silent_page.addr)
  40 #else
  41 /* fill PTB entries -- we need to fill UNIT_PAGES entries */
  42 static inline void set_ptb_entry(struct snd_emu10k1 *emu, int page, dma_addr_t addr)
  43 {
  44         int i;
  45         page *= UNIT_PAGES;
  46         for (i = 0; i < UNIT_PAGES; i++, page++) {
  47                 __set_ptb_entry(emu, page, addr);
  48                 dev_dbg(emu->card->dev, "mapped page %d to entry %.8x\n", page,
  49                         (unsigned int)__get_ptb_entry(emu, page));
  50                 addr += EMUPAGESIZE;
  51         }
  52 }
  53 static inline void set_silent_ptb(struct snd_emu10k1 *emu, int page)
  54 {
  55         int i;
  56         page *= UNIT_PAGES;
  57         for (i = 0; i < UNIT_PAGES; i++, page++) {
  58                 /* do not increment ptr */
  59                 __set_ptb_entry(emu, page, emu->silent_page.addr);
  60                 dev_dbg(emu->card->dev, "mapped silent page %d to entry %.8x\n",
  61                         page, (unsigned int)__get_ptb_entry(emu, page));
  62         }
  63 }
  64 #endif /* PAGE_SIZE */
  65
  66
  67 /*
  68  */
  69 static int synth_alloc_pages(struct snd_emu10k1 *hw, struct snd_emu10k1_memblk *blk);
  70 static int synth_free_pages(struct snd_emu10k1 *hw, struct snd_emu10k1_memblk *blk);
  71
  72 #define get_emu10k1_memblk(l,member)    list_entry(l, struct snd_emu10k1_memblk, member)
  73
  74
  75 /* initialize emu10k1 part */
  76 static void emu10k1_memblk_init(struct snd_emu10k1_memblk *blk)
  77 {
  78         blk->mapped_page = -1;
  79         INIT_LIST_HEAD(&blk->mapped_link);
  80         INIT_LIST_HEAD(&blk->mapped_order_link);
  81         blk->map_locked = 0;
  82
  83         blk->first_page = get_aligned_page(blk->mem.offset);
  84         blk->last_page = get_aligned_page(blk->mem.offset + blk->mem.size - 1);
  85         blk->pages = blk->last_page - blk->first_page + 1;
  86 }
  87
  88 /*
  89  * search empty region on PTB with the given size
  90  *
  91  * if an empty region is found, return the page and store the next mapped block
  92  * in nextp
  93  * if not found, return a negative error code.
  94  */
  95 static int search_empty_map_area(struct snd_emu10k1 *emu, int npages, struct list_head **nextp)
  96 {
  97         int page = 1, found_page = -ENOMEM;
  98         int max_size = npages;
  99         int size;
 100         struct list_head *candidate = &emu->mapped_link_head;
 101         struct list_head *pos;
 102
 103         list_for_each (pos, &emu->mapped_link_head) {
 104                 struct snd_emu10k1_memblk *blk = get_emu10k1_memblk(pos, mapped_link);
 105                 if (blk->mapped_page < 0)
 106                         continue;
 107                 size = blk->mapped_page - page;
 108                 if (size == npages) {
 109                         *nextp = pos;
 110                         return page;
 111                 }
 112                 else if (size > max_size) {
 113                         /* we look for the maximum empty hole */
 114                         max_size = size;
 115                         candidate = pos;
 116                         found_page = page;
 117                 }
 118                 page = blk->mapped_page + blk->pages;
 119         }
 120         size = (emu->address_mode ? MAX_ALIGN_PAGES1 : MAX_ALIGN_PAGES0) - page;
 121         if (size >= max_size) {
 122                 *nextp = pos;
 123                 return page;
 124         }
 125         *nextp = candidate;
 126         return found_page;
 127 }
 128
 129 /*
 130  * map a memory block onto emu10k1's PTB
 131  *
 132  * call with memblk_lock held
 133  */
 134 static int map_memblk(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
 135 {
 136         int page, pg;
 137         struct list_head *next;
 138
 139         page = search_empty_map_area(emu, blk->pages, &next);
 140         if (page < 0) /* not found */
 141                 return page;
 142         if (page == 0) {
 143                 dev_err(emu->card->dev, "trying to map zero (reserved) page\n");
 144                 return -EINVAL;
 145         }
 146         /* insert this block in the proper position of mapped list */
 147         list_add_tail(&blk->mapped_link, next);
 148         /* append this as a newest block in order list */
 149         list_add_tail(&blk->mapped_order_link, &emu->mapped_order_link_head);
 150         blk->mapped_page = page;
 151         /* fill PTB */
 152         for (pg = blk->first_page; pg <= blk->last_page; pg++) {
 153                 set_ptb_entry(emu, page, emu->page_addr_table[pg]);
 154                 page++;
 155         }
 156         return 0;
 157 }
 158
 159 /*
 160  * unmap the block
 161  * return the size of resultant empty pages
 162  *
 163  * call with memblk_lock held
 164  */
 165 static int unmap_memblk(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
 166 {
 167         int start_page, end_page, mpage, pg;
 168         struct list_head *p;
 169         struct snd_emu10k1_memblk *q;
 170
 171         /* calculate the expected size of empty region */
 172         p = blk->mapped_link.prev;
 173         if (p != &emu->mapped_link_head) {
 174                 q = get_emu10k1_memblk(p, mapped_link);
 175                 start_page = q->mapped_page + q->pages;
 176         } else {
 177                 start_page = 1;
 178         }
 179         p = blk->mapped_link.next;
 180         if (p != &emu->mapped_link_head) {
 181                 q = get_emu10k1_memblk(p, mapped_link);
 182                 end_page = q->mapped_page;
 183         } else {
 184                 end_page = (emu->address_mode ? MAX_ALIGN_PAGES1 : MAX_ALIGN_PAGES0);
 185         }
 186
 187         /* remove links */
 188         list_del(&blk->mapped_link);
 189         list_del(&blk->mapped_order_link);
 190         /* clear PTB */
 191         mpage = blk->mapped_page;
 192         for (pg = blk->first_page; pg <= blk->last_page; pg++) {
 193                 set_silent_ptb(emu, mpage);
 194                 mpage++;
 195         }
 196         blk->mapped_page = -1;
 197         return end_page - start_page; /* return the new empty size */
 198 }
 199
 200 /*
 201  * search empty pages with the given size, and create a memory block
 202  *
 203  * unlike synth_alloc the memory block is aligned to the page start
 204  */
 205 static struct snd_emu10k1_memblk *
 206 search_empty(struct snd_emu10k1 *emu, int size)
 207 {
 208         struct list_head *p;
 209         struct snd_emu10k1_memblk *blk;
 210         int page, psize;
 211
 212         psize = get_aligned_page(size + PAGE_SIZE -1);
 213         page = 0;
 214         list_for_each(p, &emu->memhdr->block) {
 215                 blk = get_emu10k1_memblk(p, mem.list);
 216                 if (page + psize <= blk->first_page)
 217                         goto __found_pages;
 218                 page = blk->last_page + 1;
 219         }
 220         if (page + psize > emu->max_cache_pages)
 221                 return NULL;
 222
 223 __found_pages:
 224         /* create a new memory block */
 225         blk = (struct snd_emu10k1_memblk *)__snd_util_memblk_new(emu->memhdr, psize << PAGE_SHIFT, p->prev);
 226         if (blk == NULL)
 227                 return NULL;
 228         blk->mem.offset = aligned_page_offset(page); /* set aligned offset */
 229         emu10k1_memblk_init(blk);
 230         return blk;
 231 }
 232
 233
 234 /*
 235  * check if the given pointer is valid for pages
 236  */
 237 static int is_valid_page(struct snd_emu10k1 *emu, dma_addr_t addr)
 238 {
 239         if (addr & ~emu->dma_mask) {
 240                 dev_err_ratelimited(emu->card->dev,
 241                         "max memory size is 0x%lx (addr = 0x%lx)!!\n",
 242                         emu->dma_mask, (unsigned long)addr);
 243                 return 0;
 244         }
 245         if (addr & (EMUPAGESIZE-1)) {
 246                 dev_err_ratelimited(emu->card->dev, "page is not aligned\n");
 247                 return 0;
 248         }
 249         return 1;
 250 }
 251
 252 /*
 253  * map the given memory block on PTB.
 254  * if the block is already mapped, update the link order.
 255  * if no empty pages are found, tries to release unused memory blocks
 256  * and retry the mapping.
 257  */
 258 int snd_emu10k1_memblk_map(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
 259 {
 260         int err;
 261         int size;
 262         struct list_head *p, *nextp;
 263         struct snd_emu10k1_memblk *deleted;
 264         unsigned long flags;
 265
 266         spin_lock_irqsave(&emu->memblk_lock, flags);
 267         if (blk->mapped_page >= 0) {
 268                 /* update order link */
 269                 list_move_tail(&blk->mapped_order_link,
 270                                &emu->mapped_order_link_head);
 271                 spin_unlock_irqrestore(&emu->memblk_lock, flags);
 272                 return 0;
 273         }
 274         err = map_memblk(emu, blk);
 275         if (err < 0) {
 276                 /* no enough page - try to unmap some blocks */
 277                 /* starting from the oldest block */
 278                 p = emu->mapped_order_link_head.next;
 279                 for (; p != &emu->mapped_order_link_head; p = nextp) {
 280                         nextp = p->next;
 281                         deleted = get_emu10k1_memblk(p, mapped_order_link);
 282                         if (deleted->map_locked)
 283                                 continue;
 284                         size = unmap_memblk(emu, deleted);
 285                         if (size >= blk->pages) {
 286                                 /* ok the empty region is enough large */
 287                                 err = map_memblk(emu, blk);
 288                                 break;
 289                         }
 290                 }
 291         }
 292         spin_unlock_irqrestore(&emu->memblk_lock, flags);
 293         return err;
 294 }
 295
 296 EXPORT_SYMBOL(snd_emu10k1_memblk_map);
 297
 298 /*
 299  * page allocation for DMA
 300  */
 301 struct snd_util_memblk *
 302 snd_emu10k1_alloc_pages(struct snd_emu10k1 *emu, struct snd_pcm_substream *substream)
 303 {
 304         struct snd_pcm_runtime *runtime = substream->runtime;
 305         struct snd_util_memhdr *hdr;
 306         struct snd_emu10k1_memblk *blk;
 307         int page, err, idx;
 308
 309         if (snd_BUG_ON(!emu))
 310                 return NULL;
 311         if (snd_BUG_ON(runtime->dma_bytes <= 0 ||
 312                        runtime->dma_bytes >= (emu->address_mode ? MAXPAGES1 : MAXPAGES0) * EMUPAGESIZE))
 313                 return NULL;
 314         hdr = emu->memhdr;
 315         if (snd_BUG_ON(!hdr))
 316                 return NULL;
 317
 318         mutex_lock(&hdr->block_mutex);
 319         blk = search_empty(emu, runtime->dma_bytes);
 320         if (blk == NULL) {
 321                 mutex_unlock(&hdr->block_mutex);
 322                 return NULL;
 323         }
 324         /* fill buffer addresses but pointers are not stored so that
 325          * snd_free_pci_page() is not called in synth_free()
 326          */
 327         idx = 0;
 328         for (page = blk->first_page; page <= blk->last_page; page++, idx++) {
 329                 unsigned long ofs = idx << PAGE_SHIFT;
 330                 dma_addr_t addr;
 331                 if (ofs >= runtime->dma_bytes)
 332                         addr = emu->silent_page.addr;
 333                 else
 334                         addr = snd_pcm_sgbuf_get_addr(substream, ofs);
 335                 if (! is_valid_page(emu, addr)) {
 336                         dev_err_ratelimited(emu->card->dev,
 337                                 "emu: failure page = %d\n", idx);
 338                         mutex_unlock(&hdr->block_mutex);
 339                         return NULL;
 340                 }
 341                 emu->page_addr_table[page] = addr;
 342                 emu->page_ptr_table[page] = NULL;
 343         }
 344
 345         /* set PTB entries */
 346         blk->map_locked = 1; /* do not unmap this block! */
 347         err = snd_emu10k1_memblk_map(emu, blk);
 348         if (err < 0) {
 349                 __snd_util_mem_free(hdr, (struct snd_util_memblk *)blk);
 350                 mutex_unlock(&hdr->block_mutex);
 351                 return NULL;
 352         }
 353         mutex_unlock(&hdr->block_mutex);
 354         return (struct snd_util_memblk *)blk;
 355 }
 356
 357
 358 /*
 359  * release DMA buffer from page table
 360  */
 361 int snd_emu10k1_free_pages(struct snd_emu10k1 *emu, struct snd_util_memblk *blk)
 362 {
 363         if (snd_BUG_ON(!emu || !blk))
 364                 return -EINVAL;
 365         return snd_emu10k1_synth_free(emu, blk);
 366 }
 367
 368 /*
 369  * allocate DMA pages, widening the allocation if necessary
 370  *
 371  * See the comment above snd_emu10k1_detect_iommu() in emu10k1_main.c why
 372  * this might be needed.
 373  *
 374  * If you modify this function check whether __synth_free_pages() also needs
 375  * changes.
 376  */
 377 int snd_emu10k1_alloc_pages_maybe_wider(struct snd_emu10k1 *emu, size_t size,
 378                                         struct snd_dma_buffer *dmab)
 379 {
 380         if (emu->iommu_workaround) {
 381                 size_t npages = DIV_ROUND_UP(size, PAGE_SIZE);
 382                 size_t size_real = npages * PAGE_SIZE;
 383
 384                 /*
 385                  * The device has been observed to accesses up to 256 extra
 386                  * bytes, but use 1k to be safe.
 387                  */
 388                 if (size_real < size + 1024)
 389                         size += PAGE_SIZE;
 390         }
 391
 392         return snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV,
 393                                    &emu->pci->dev, size, dmab);
 394 }
 395
 396 /*
 397  * memory allocation using multiple pages (for synth)
 398  * Unlike the DMA allocation above, non-contiguous pages are assined.
 399  */
 400
 401 /*
 402  * allocate a synth sample area
 403  */
 404 struct snd_util_memblk *
 405 snd_emu10k1_synth_alloc(struct snd_emu10k1 *hw, unsigned int size)
 406 {
 407         struct snd_emu10k1_memblk *blk;
 408         struct snd_util_memhdr *hdr = hw->memhdr;
 409
 410         mutex_lock(&hdr->block_mutex);
 411         blk = (struct snd_emu10k1_memblk *)__snd_util_mem_alloc(hdr, size);
 412         if (blk == NULL) {
 413                 mutex_unlock(&hdr->block_mutex);
 414                 return NULL;
 415         }
 416         if (synth_alloc_pages(hw, blk)) {
 417                 __snd_util_mem_free(hdr, (struct snd_util_memblk *)blk);
 418                 mutex_unlock(&hdr->block_mutex);
 419                 return NULL;
 420         }
 421         snd_emu10k1_memblk_map(hw, blk);
 422         mutex_unlock(&hdr->block_mutex);
 423         return (struct snd_util_memblk *)blk;
 424 }
 425
 426 EXPORT_SYMBOL(snd_emu10k1_synth_alloc);
 427
 428 /*
 429  * free a synth sample area
 430  */
 431 int
 432 snd_emu10k1_synth_free(struct snd_emu10k1 *emu, struct snd_util_memblk *memblk)
 433 {
 434         struct snd_util_memhdr *hdr = emu->memhdr;
 435         struct snd_emu10k1_memblk *blk = (struct snd_emu10k1_memblk *)memblk;
 436         unsigned long flags;
 437
 438         mutex_lock(&hdr->block_mutex);
 439         spin_lock_irqsave(&emu->memblk_lock, flags);
 440         if (blk->mapped_page >= 0)
 441                 unmap_memblk(emu, blk);
 442         spin_unlock_irqrestore(&emu->memblk_lock, flags);
 443         synth_free_pages(emu, blk);
 444          __snd_util_mem_free(hdr, memblk);
 445         mutex_unlock(&hdr->block_mutex);
 446         return 0;
 447 }
 448
 449 EXPORT_SYMBOL(snd_emu10k1_synth_free);
 450
 451 /* check new allocation range */
 452 static void get_single_page_range(struct snd_util_memhdr *hdr,
 453                                   struct snd_emu10k1_memblk *blk,
 454                                   int *first_page_ret, int *last_page_ret)
 455 {
 456         struct list_head *p;
 457         struct snd_emu10k1_memblk *q;
 458         int first_page, last_page;
 459         first_page = blk->first_page;
 460         p = blk->mem.list.prev;
 461         if (p != &hdr->block) {
 462                 q = get_emu10k1_memblk(p, mem.list);
 463                 if (q->last_page == first_page)
 464                         first_page++;  /* first page was already allocated */
 465         }
 466         last_page = blk->last_page;
 467         p = blk->mem.list.next;
 468         if (p != &hdr->block) {
 469                 q = get_emu10k1_memblk(p, mem.list);
 470                 if (q->first_page == last_page)
 471                         last_page--; /* last page was already allocated */
 472         }
 473         *first_page_ret = first_page;
 474         *last_page_ret = last_page;
 475 }
 476
 477 /* release allocated pages */
 478 static void __synth_free_pages(struct snd_emu10k1 *emu, int first_page,
 479                                int last_page)
 480 {
 481         struct snd_dma_buffer dmab;
 482         int page;
 483
 484         dmab.dev.type = SNDRV_DMA_TYPE_DEV;
 485         dmab.dev.dev = &emu->pci->dev;
 486
 487         for (page = first_page; page <= last_page; page++) {
 488                 if (emu->page_ptr_table[page] == NULL)
 489                         continue;
 490                 dmab.area = emu->page_ptr_table[page];
 491                 dmab.addr = emu->page_addr_table[page];
 492
 493                 /*
 494                  * please keep me in sync with logic in
 495                  * snd_emu10k1_alloc_pages_maybe_wider()
 496                  */
 497                 dmab.bytes = PAGE_SIZE;
 498                 if (emu->iommu_workaround)
 499                         dmab.bytes *= 2;
 500
 501                 snd_dma_free_pages(&dmab);
 502                 emu->page_addr_table[page] = 0;
 503                 emu->page_ptr_table[page] = NULL;
 504         }
 505 }
 506
 507 /*
 508  * allocate kernel pages
 509  */
 510 static int synth_alloc_pages(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
 511 {
 512         int page, first_page, last_page;
 513         struct snd_dma_buffer dmab;
 514
 515         emu10k1_memblk_init(blk);
 516         get_single_page_range(emu->memhdr, blk, &first_page, &last_page);
 517         /* allocate kernel pages */
 518         for (page = first_page; page <= last_page; page++) {
 519                 if (snd_emu10k1_alloc_pages_maybe_wider(emu, PAGE_SIZE,
 520                                                         &dmab) < 0)
 521                         goto __fail;
 522                 if (!is_valid_page(emu, dmab.addr)) {
 523                         snd_dma_free_pages(&dmab);
 524                         goto __fail;
 525                 }
 526                 emu->page_addr_table[page] = dmab.addr;
 527                 emu->page_ptr_table[page] = dmab.area;
 528         }
 529         return 0;
 530
 531 __fail:
 532         /* release allocated pages */
 533         last_page = page - 1;
 534         __synth_free_pages(emu, first_page, last_page);
 535
 536         return -ENOMEM;
 537 }
 538
 539 /*
 540  * free pages
 541  */
 542 static int synth_free_pages(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
 543 {
 544         int first_page, last_page;
 545
 546         get_single_page_range(emu->memhdr, blk, &first_page, &last_page);
 547         __synth_free_pages(emu, first_page, last_page);
 548         return 0;
 549 }
 550
 551 /* calculate buffer pointer from offset address */
 552 static inline void *offset_ptr(struct snd_emu10k1 *emu, int page, int offset)
 553 {
 554         char *ptr;
 555         if (snd_BUG_ON(page < 0 || page >= emu->max_cache_pages))
 556                 return NULL;
 557         ptr = emu->page_ptr_table[page];
 558         if (! ptr) {
 559                 dev_err(emu->card->dev,
 560                         "access to NULL ptr: page = %d\n", page);
 561                 return NULL;
 562         }
 563         ptr += offset & (PAGE_SIZE - 1);
 564         return (void*)ptr;
 565 }
 566
 567 /*
 568  * bzero(blk + offset, size)
 569  */
 570 int snd_emu10k1_synth_bzero(struct snd_emu10k1 *emu, struct snd_util_memblk *blk,
 571                             int offset, int size)
 572 {
 573         int page, nextofs, end_offset, temp, temp1;
 574         void *ptr;
 575         struct snd_emu10k1_memblk *p = (struct snd_emu10k1_memblk *)blk;
 576
 577         offset += blk->offset & (PAGE_SIZE - 1);
 578         end_offset = offset + size;
 579         page = get_aligned_page(offset);
 580         do {
 581                 nextofs = aligned_page_offset(page + 1);
 582                 temp = nextofs - offset;
 583                 temp1 = end_offset - offset;
 584                 if (temp1 < temp)
 585                         temp = temp1;
 586                 ptr = offset_ptr(emu, page + p->first_page, offset);
 587                 if (ptr)
 588                         memset(ptr, 0, temp);
 589                 offset = nextofs;
 590                 page++;
 591         } while (offset < end_offset);
 592         return 0;
 593 }
 594
 595 EXPORT_SYMBOL(snd_emu10k1_synth_bzero);
 596
 597 /*
 598  * copy_from_user(blk + offset, data, size)
 599  */
 600 int snd_emu10k1_synth_copy_from_user(struct snd_emu10k1 *emu, struct snd_util_memblk *blk,
 601                                      int offset, const char __user *data, int size)
 602 {
 603         int page, nextofs, end_offset, temp, temp1;
 604         void *ptr;
 605         struct snd_emu10k1_memblk *p = (struct snd_emu10k1_memblk *)blk;
 606
 607         offset += blk->offset & (PAGE_SIZE - 1);
 608         end_offset = offset + size;
 609         page = get_aligned_page(offset);
 610         do {
 611                 nextofs = aligned_page_offset(page + 1);
 612                 temp = nextofs - offset;
 613                 temp1 = end_offset - offset;
 614                 if (temp1 < temp)
 615                         temp = temp1;
 616                 ptr = offset_ptr(emu, page + p->first_page, offset);
 617                 if (ptr && copy_from_user(ptr, data, temp))
 618                         return -EFAULT;
 619                 offset = nextofs;
 620                 data += temp;
 621                 page++;
 622         } while (offset < end_offset);
 623         return 0;
 624 }
 625
 626 EXPORT_SYMBOL(snd_emu10k1_synth_copy_from_user);