arch/parisc/kernel/pci-dma.c

   1 /*
   2 ** PARISC 1.1 Dynamic DMA mapping support.
   3 ** This implementation is for PA-RISC platforms that do not support
   4 ** I/O TLBs (aka DMA address translation hardware).
   5 ** See Documentation/DMA-mapping.txt for interface definitions.
   6 **
   7 **      (c) Copyright 1999,2000 Hewlett-Packard Company
   8 **      (c) Copyright 2000 Grant Grundler
   9 **      (c) Copyright 2000 Philipp Rumpf <prumpf@tux.org>
  10 **      (c) Copyright 2000 John Marvin
  11 **
  12 ** "leveraged" from 2.3.47: arch/ia64/kernel/pci-dma.c.
  13 ** (I assume it's from David Mosberger-Tang but there was no Copyright)
  14 **
  15 ** AFAIK, all PA7100LC and PA7300LC platforms can use this code.
  16 **
  17 ** - ggg
  18 */
  19
  20 #include <linux/init.h>
  21 #include <linux/mm.h>
  22 #include <linux/pci.h>
  23 #include <linux/proc_fs.h>
  24 #include <linux/slab.h>
  25 #include <linux/string.h>
  26 #include <linux/types.h>
  27
  28 #include <asm/cacheflush.h>
  29 #include <asm/dma.h>    /* for DMA_CHUNK_SIZE */
  30 #include <asm/io.h>
  31 #include <asm/page.h>   /* get_order */
  32 #include <asm/pgalloc.h>
  33 #include <asm/uaccess.h>
  34 #include <asm/tlbflush.h>       /* for purge_tlb_*() macros */
  35
  36 static struct proc_dir_entry * proc_gsc_root __read_mostly = NULL;
  37 static int pcxl_proc_info(char *buffer, char **start, off_t offset, int length);
  38 static unsigned long pcxl_used_bytes __read_mostly = 0;
  39 static unsigned long pcxl_used_pages __read_mostly = 0;
  40
  41 extern unsigned long pcxl_dma_start; /* Start of pcxl dma mapping area */
  42 static spinlock_t   pcxl_res_lock;
  43 static char    *pcxl_res_map;
  44 static int     pcxl_res_hint;
  45 static int     pcxl_res_size;
  46
  47 #ifdef DEBUG_PCXL_RESOURCE
  48 #define DBG_RES(x...)   printk(x)
  49 #else
  50 #define DBG_RES(x...)
  51 #endif
  52
  53
  54 /*
  55 ** Dump a hex representation of the resource map.
  56 */
  57
  58 #ifdef DUMP_RESMAP
  59 static
  60 void dump_resmap(void)
  61 {
  62         u_long *res_ptr = (unsigned long *)pcxl_res_map;
  63         u_long i = 0;
  64
  65         printk("res_map: ");
  66         for(; i < (pcxl_res_size / sizeof(unsigned long)); ++i, ++res_ptr)
  67                 printk("%08lx ", *res_ptr);
  68
  69         printk("\n");
  70 }
  71 #else
  72 static inline void dump_resmap(void) {;}
  73 #endif
  74
  75 static int pa11_dma_supported( struct device *dev, u64 mask)
  76 {
  77         return 1;
  78 }
  79
  80 static inline int map_pte_uncached(pte_t * pte,
  81                 unsigned long vaddr,
  82                 unsigned long size, unsigned long *paddr_ptr)
  83 {
  84         unsigned long end;
  85         unsigned long orig_vaddr = vaddr;
  86
  87         vaddr &= ~PMD_MASK;
  88         end = vaddr + size;
  89         if (end > PMD_SIZE)
  90                 end = PMD_SIZE;
  91         do {
  92                 if (!pte_none(*pte))
  93                         printk(KERN_ERR "map_pte_uncached: page already exists\n");
  94                 set_pte(pte, __mk_pte(*paddr_ptr, PAGE_KERNEL_UNC));
  95                 purge_tlb_start();
  96                 pdtlb_kernel(orig_vaddr);
  97                 purge_tlb_end();
  98                 vaddr += PAGE_SIZE;
  99                 orig_vaddr += PAGE_SIZE;
 100                 (*paddr_ptr) += PAGE_SIZE;
 101                 pte++;
 102         } while (vaddr < end);
 103         return 0;
 104 }
 105
 106 static inline int map_pmd_uncached(pmd_t * pmd, unsigned long vaddr,
 107                 unsigned long size, unsigned long *paddr_ptr)
 108 {
 109         unsigned long end;
 110         unsigned long orig_vaddr = vaddr;
 111
 112         vaddr &= ~PGDIR_MASK;
 113         end = vaddr + size;
 114         if (end > PGDIR_SIZE)
 115                 end = PGDIR_SIZE;
 116         do {
 117                 pte_t * pte = pte_alloc_kernel(pmd, vaddr);
 118                 if (!pte)
 119                         return -ENOMEM;
 120                 if (map_pte_uncached(pte, orig_vaddr, end - vaddr, paddr_ptr))
 121                         return -ENOMEM;
 122                 vaddr = (vaddr + PMD_SIZE) & PMD_MASK;
 123                 orig_vaddr += PMD_SIZE;
 124                 pmd++;
 125         } while (vaddr < end);
 126         return 0;
 127 }
 128
 129 static inline int map_uncached_pages(unsigned long vaddr, unsigned long size,
 130                 unsigned long paddr)
 131 {
 132         pgd_t * dir;
 133         unsigned long end = vaddr + size;
 134
 135         dir = pgd_offset_k(vaddr);
 136         do {
 137                 pmd_t *pmd;
 138
 139                 pmd = pmd_alloc(NULL, dir, vaddr);
 140                 if (!pmd)
 141                         return -ENOMEM;
 142                 if (map_pmd_uncached(pmd, vaddr, end - vaddr, &paddr))
 143                         return -ENOMEM;
 144                 vaddr = vaddr + PGDIR_SIZE;
 145                 dir++;
 146         } while (vaddr && (vaddr < end));
 147         return 0;
 148 }
 149
 150 static inline void unmap_uncached_pte(pmd_t * pmd, unsigned long vaddr,
 151                 unsigned long size)
 152 {
 153         pte_t * pte;
 154         unsigned long end;
 155         unsigned long orig_vaddr = vaddr;
 156
 157         if (pmd_none(*pmd))
 158                 return;
 159         if (pmd_bad(*pmd)) {
 160                 pmd_ERROR(*pmd);
 161                 pmd_clear(pmd);
 162                 return;
 163         }
 164         pte = pte_offset_map(pmd, vaddr);
 165         vaddr &= ~PMD_MASK;
 166         end = vaddr + size;
 167         if (end > PMD_SIZE)
 168                 end = PMD_SIZE;
 169         do {
 170                 pte_t page = *pte;
 171                 pte_clear(&init_mm, vaddr, pte);
 172                 purge_tlb_start();
 173                 pdtlb_kernel(orig_vaddr);
 174                 purge_tlb_end();
 175                 vaddr += PAGE_SIZE;
 176                 orig_vaddr += PAGE_SIZE;
 177                 pte++;
 178                 if (pte_none(page) || pte_present(page))
 179                         continue;
 180                 printk(KERN_CRIT "Whee.. Swapped out page in kernel page table\n");
 181         } while (vaddr < end);
 182 }
 183
 184 static inline void unmap_uncached_pmd(pgd_t * dir, unsigned long vaddr,
 185                 unsigned long size)
 186 {
 187         pmd_t * pmd;
 188         unsigned long end;
 189         unsigned long orig_vaddr = vaddr;
 190
 191         if (pgd_none(*dir))
 192                 return;
 193         if (pgd_bad(*dir)) {
 194                 pgd_ERROR(*dir);
 195                 pgd_clear(dir);
 196                 return;
 197         }
 198         pmd = pmd_offset(dir, vaddr);
 199         vaddr &= ~PGDIR_MASK;
 200         end = vaddr + size;
 201         if (end > PGDIR_SIZE)
 202                 end = PGDIR_SIZE;
 203         do {
 204                 unmap_uncached_pte(pmd, orig_vaddr, end - vaddr);
 205                 vaddr = (vaddr + PMD_SIZE) & PMD_MASK;
 206                 orig_vaddr += PMD_SIZE;
 207                 pmd++;
 208         } while (vaddr < end);
 209 }
 210
 211 static void unmap_uncached_pages(unsigned long vaddr, unsigned long size)
 212 {
 213         pgd_t * dir;
 214         unsigned long end = vaddr + size;
 215
 216         dir = pgd_offset_k(vaddr);
 217         do {
 218                 unmap_uncached_pmd(dir, vaddr, end - vaddr);
 219                 vaddr = vaddr + PGDIR_SIZE;
 220                 dir++;
 221         } while (vaddr && (vaddr < end));
 222 }
 223
 224 #define PCXL_SEARCH_LOOP(idx, mask, size)  \
 225        for(; res_ptr < res_end; ++res_ptr) \
 226        { \
 227                if(0 == ((*res_ptr) & mask)) { \
 228                        *res_ptr |= mask; \
 229                        idx = (int)((u_long)res_ptr - (u_long)pcxl_res_map); \
 230                        pcxl_res_hint = idx + (size >> 3); \
 231                        goto resource_found; \
 232                } \
 233        }
 234
 235 #define PCXL_FIND_FREE_MAPPING(idx, mask, size)  { \
 236        u##size *res_ptr = (u##size *)&(pcxl_res_map[pcxl_res_hint & ~((size >> 3) - 1)]); \
 237        u##size *res_end = (u##size *)&pcxl_res_map[pcxl_res_size]; \
 238        PCXL_SEARCH_LOOP(idx, mask, size); \
 239        res_ptr = (u##size *)&pcxl_res_map[0]; \
 240        PCXL_SEARCH_LOOP(idx, mask, size); \
 241 }
 242
 243 unsigned long
 244 pcxl_alloc_range(size_t size)
 245 {
 246         int res_idx;
 247         u_long mask, flags;
 248         unsigned int pages_needed = size >> PAGE_SHIFT;
 249
 250         mask = (u_long) -1L;
 251         mask >>= BITS_PER_LONG - pages_needed;
 252
 253         DBG_RES("pcxl_alloc_range() size: %d pages_needed %d pages_mask 0x%08lx\n",
 254                 size, pages_needed, mask);
 255
 256         spin_lock_irqsave(&pcxl_res_lock, flags);
 257
 258         if(pages_needed <= 8) {
 259                 PCXL_FIND_FREE_MAPPING(res_idx, mask, 8);
 260         } else if(pages_needed <= 16) {
 261                 PCXL_FIND_FREE_MAPPING(res_idx, mask, 16);
 262         } else if(pages_needed <= 32) {
 263                 PCXL_FIND_FREE_MAPPING(res_idx, mask, 32);
 264         } else {
 265                 panic("%s: pcxl_alloc_range() Too many pages to map.\n",
 266                       __FILE__);
 267         }
 268
 269         dump_resmap();
 270         panic("%s: pcxl_alloc_range() out of dma mapping resources\n",
 271               __FILE__);
 272
 273 resource_found:
 274
 275         DBG_RES("pcxl_alloc_range() res_idx %d mask 0x%08lx res_hint: %d\n",
 276                 res_idx, mask, pcxl_res_hint);
 277
 278         pcxl_used_pages += pages_needed;
 279         pcxl_used_bytes += ((pages_needed >> 3) ? (pages_needed >> 3) : 1);
 280
 281         spin_unlock_irqrestore(&pcxl_res_lock, flags);
 282
 283         dump_resmap();
 284
 285         /*
 286         ** return the corresponding vaddr in the pcxl dma map
 287         */
 288         return (pcxl_dma_start + (res_idx << (PAGE_SHIFT + 3)));
 289 }
 290
 291 #define PCXL_FREE_MAPPINGS(idx, m, size) \
 292                 u##size *res_ptr = (u##size *)&(pcxl_res_map[(idx) + (((size >> 3) - 1) & (~((size >> 3) - 1)))]); \
 293                 /* BUG_ON((*res_ptr & m) != m); */ \
 294                 *res_ptr &= ~m;
 295
 296 /*
 297 ** clear bits in the pcxl resource map
 298 */
 299 static void
 300 pcxl_free_range(unsigned long vaddr, size_t size)
 301 {
 302         u_long mask, flags;
 303         unsigned int res_idx = (vaddr - pcxl_dma_start) >> (PAGE_SHIFT + 3);
 304         unsigned int pages_mapped = size >> PAGE_SHIFT;
 305
 306         mask = (u_long) -1L;
 307         mask >>= BITS_PER_LONG - pages_mapped;
 308
 309         DBG_RES("pcxl_free_range() res_idx: %d size: %d pages_mapped %d mask 0x%08lx\n",
 310                 res_idx, size, pages_mapped, mask);
 311
 312         spin_lock_irqsave(&pcxl_res_lock, flags);
 313
 314         if(pages_mapped <= 8) {
 315                 PCXL_FREE_MAPPINGS(res_idx, mask, 8);
 316         } else if(pages_mapped <= 16) {
 317                 PCXL_FREE_MAPPINGS(res_idx, mask, 16);
 318         } else if(pages_mapped <= 32) {
 319                 PCXL_FREE_MAPPINGS(res_idx, mask, 32);
 320         } else {
 321                 panic("%s: pcxl_free_range() Too many pages to unmap.\n",
 322                       __FILE__);
 323         }
 324
 325         pcxl_used_pages -= (pages_mapped ? pages_mapped : 1);
 326         pcxl_used_bytes -= ((pages_mapped >> 3) ? (pages_mapped >> 3) : 1);
 327
 328         spin_unlock_irqrestore(&pcxl_res_lock, flags);
 329
 330         dump_resmap();
 331 }
 332
 333 static int __init
 334 pcxl_dma_init(void)
 335 {
 336         if (pcxl_dma_start == 0)
 337                 return 0;
 338
 339         spin_lock_init(&pcxl_res_lock);
 340         pcxl_res_size = PCXL_DMA_MAP_SIZE >> (PAGE_SHIFT + 3);
 341         pcxl_res_hint = 0;
 342         pcxl_res_map = (char *)__get_free_pages(GFP_KERNEL,
 343                                             get_order(pcxl_res_size));
 344         memset(pcxl_res_map, 0, pcxl_res_size);
 345         proc_gsc_root = proc_mkdir("gsc", 0);
 346         if (!proc_gsc_root)
 347                 printk(KERN_WARNING
 348                         "pcxl_dma_init: Unable to create gsc /proc dir entry\n");
 349         else {
 350                 struct proc_dir_entry* ent;
 351                 ent = create_proc_info_entry("pcxl_dma", 0,
 352                                 proc_gsc_root, pcxl_proc_info);
 353                 if (!ent)
 354                         printk(KERN_WARNING
 355                                 "pci-dma.c: Unable to create pcxl_dma /proc entry.\n");
 356         }
 357         return 0;
 358 }
 359
 360 __initcall(pcxl_dma_init);
 361
 362 static void * pa11_dma_alloc_consistent (struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t flag)
 363 {
 364         unsigned long vaddr;
 365         unsigned long paddr;
 366         int order;
 367
 368         order = get_order(size);
 369         size = 1 << (order + PAGE_SHIFT);
 370         vaddr = pcxl_alloc_range(size);
 371         paddr = __get_free_pages(flag, order);
 372         flush_kernel_dcache_range(paddr, size);
 373         paddr = __pa(paddr);
 374         map_uncached_pages(vaddr, size, paddr);
 375         *dma_handle = (dma_addr_t) paddr;
 376
 377 #if 0
 378 /* This probably isn't needed to support EISA cards.
 379 ** ISA cards will certainly only support 24-bit DMA addressing.
 380 ** Not clear if we can, want, or need to support ISA.
 381 */
 382         if (!dev || *dev->coherent_dma_mask < 0xffffffff)
 383                 gfp |= GFP_DMA;
 384 #endif
 385         return (void *)vaddr;
 386 }
 387
 388 static void pa11_dma_free_consistent (struct device *dev, size_t size, void *vaddr, dma_addr_t dma_handle)
 389 {
 390         int order;
 391
 392         order = get_order(size);
 393         size = 1 << (order + PAGE_SHIFT);
 394         unmap_uncached_pages((unsigned long)vaddr, size);
 395         pcxl_free_range((unsigned long)vaddr, size);
 396         free_pages((unsigned long)__va(dma_handle), order);
 397 }
 398
 399 static dma_addr_t pa11_dma_map_single(struct device *dev, void *addr, size_t size, enum dma_data_direction direction)
 400 {
 401         if (direction == DMA_NONE) {
 402                 printk(KERN_ERR "pa11_dma_map_single(PCI_DMA_NONE) called by %p\n", __builtin_return_address(0));
 403                 BUG();
 404         }
 405
 406         flush_kernel_dcache_range((unsigned long) addr, size);
 407         return virt_to_phys(addr);
 408 }
 409
 410 static void pa11_dma_unmap_single(struct device *dev, dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
 411 {
 412         if (direction == DMA_NONE) {
 413                 printk(KERN_ERR "pa11_dma_unmap_single(PCI_DMA_NONE) called by %p\n", __builtin_return_address(0));
 414                 BUG();
 415         }
 416
 417         if (direction == DMA_TO_DEVICE)
 418             return;
 419
 420         /*
 421          * For PCI_DMA_FROMDEVICE this flush is not necessary for the
 422          * simple map/unmap case. However, it IS necessary if if
 423          * pci_dma_sync_single_* has been called and the buffer reused.
 424          */
 425
 426         flush_kernel_dcache_range((unsigned long) phys_to_virt(dma_handle), size);
 427         return;
 428 }
 429
 430 static int pa11_dma_map_sg(struct device *dev, struct scatterlist *sglist, int nents, enum dma_data_direction direction)
 431 {
 432         int i;
 433
 434         if (direction == DMA_NONE)
 435             BUG();
 436
 437         for (i = 0; i < nents; i++, sglist++ ) {
 438                 unsigned long vaddr = sg_virt_addr(sglist);
 439                 sg_dma_address(sglist) = (dma_addr_t) virt_to_phys(vaddr);
 440                 sg_dma_len(sglist) = sglist->length;
 441                 flush_kernel_dcache_range(vaddr, sglist->length);
 442         }
 443         return nents;
 444 }
 445
 446 static void pa11_dma_unmap_sg(struct device *dev, struct scatterlist *sglist, int nents, enum dma_data_direction direction)
 447 {
 448         int i;
 449
 450         if (direction == DMA_NONE)
 451             BUG();
 452
 453         if (direction == DMA_TO_DEVICE)
 454             return;
 455
 456         /* once we do combining we'll need to use phys_to_virt(sg_dma_address(sglist)) */
 457
 458         for (i = 0; i < nents; i++, sglist++ )
 459                 flush_kernel_dcache_range(sg_virt_addr(sglist), sglist->length);
 460         return;
 461 }
 462
 463 static void pa11_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle, unsigned long offset, size_t size, enum dma_data_direction direction)
 464 {
 465         if (direction == DMA_NONE)
 466             BUG();
 467
 468         flush_kernel_dcache_range((unsigned long) phys_to_virt(dma_handle) + offset, size);
 469 }
 470
 471 static void pa11_dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle, unsigned long offset, size_t size, enum dma_data_direction direction)
 472 {
 473         if (direction == DMA_NONE)
 474             BUG();
 475
 476         flush_kernel_dcache_range((unsigned long) phys_to_virt(dma_handle) + offset, size);
 477 }
 478
 479 static void pa11_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sglist, int nents, enum dma_data_direction direction)
 480 {
 481         int i;
 482
 483         /* once we do combining we'll need to use phys_to_virt(sg_dma_address(sglist)) */
 484
 485         for (i = 0; i < nents; i++, sglist++ )
 486                 flush_kernel_dcache_range(sg_virt_addr(sglist), sglist->length);
 487 }
 488
 489 static void pa11_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sglist, int nents, enum dma_data_direction direction)
 490 {
 491         int i;
 492
 493         /* once we do combining we'll need to use phys_to_virt(sg_dma_address(sglist)) */
 494
 495         for (i = 0; i < nents; i++, sglist++ )
 496                 flush_kernel_dcache_range(sg_virt_addr(sglist), sglist->length);
 497 }
 498
 499 struct hppa_dma_ops pcxl_dma_ops = {
 500         .dma_supported =        pa11_dma_supported,
 501         .alloc_consistent =     pa11_dma_alloc_consistent,
 502         .alloc_noncoherent =    pa11_dma_alloc_consistent,
 503         .free_consistent =      pa11_dma_free_consistent,
 504         .map_single =           pa11_dma_map_single,
 505         .unmap_single =         pa11_dma_unmap_single,
 506         .map_sg =               pa11_dma_map_sg,
 507         .unmap_sg =             pa11_dma_unmap_sg,
 508         .dma_sync_single_for_cpu = pa11_dma_sync_single_for_cpu,
 509         .dma_sync_single_for_device = pa11_dma_sync_single_for_device,
 510         .dma_sync_sg_for_cpu = pa11_dma_sync_sg_for_cpu,
 511         .dma_sync_sg_for_device = pa11_dma_sync_sg_for_device,
 512 };
 513
 514 static void *fail_alloc_consistent(struct device *dev, size_t size,
 515                                    dma_addr_t *dma_handle, gfp_t flag)
 516 {
 517         return NULL;
 518 }
 519
 520 static void *pa11_dma_alloc_noncoherent(struct device *dev, size_t size,
 521                                           dma_addr_t *dma_handle, gfp_t flag)
 522 {
 523         void *addr = NULL;
 524
 525         /* rely on kmalloc to be cacheline aligned */
 526         addr = kmalloc(size, flag);
 527         if(addr)
 528                 *dma_handle = (dma_addr_t)virt_to_phys(addr);
 529
 530         return addr;
 531 }
 532
 533 static void pa11_dma_free_noncoherent(struct device *dev, size_t size,
 534                                         void *vaddr, dma_addr_t iova)
 535 {
 536         kfree(vaddr);
 537         return;
 538 }
 539
 540 struct hppa_dma_ops pcx_dma_ops = {
 541         .dma_supported =        pa11_dma_supported,
 542         .alloc_consistent =     fail_alloc_consistent,
 543         .alloc_noncoherent =    pa11_dma_alloc_noncoherent,
 544         .free_consistent =      pa11_dma_free_noncoherent,
 545         .map_single =           pa11_dma_map_single,
 546         .unmap_single =         pa11_dma_unmap_single,
 547         .map_sg =               pa11_dma_map_sg,
 548         .unmap_sg =             pa11_dma_unmap_sg,
 549         .dma_sync_single_for_cpu =      pa11_dma_sync_single_for_cpu,
 550         .dma_sync_single_for_device =   pa11_dma_sync_single_for_device,
 551         .dma_sync_sg_for_cpu =          pa11_dma_sync_sg_for_cpu,
 552         .dma_sync_sg_for_device =       pa11_dma_sync_sg_for_device,
 553 };
 554
 555
 556 static int pcxl_proc_info(char *buf, char **start, off_t offset, int len)
 557 {
 558 #if 0
 559         u_long i = 0;
 560         unsigned long *res_ptr = (u_long *)pcxl_res_map;
 561 #endif
 562         unsigned long total_pages = pcxl_res_size << 3;   /* 8 bits per byte */
 563
 564         sprintf(buf, "\nDMA Mapping Area size    : %d bytes (%ld pages)\n",
 565                 PCXL_DMA_MAP_SIZE, total_pages);
 566
 567         sprintf(buf, "%sResource bitmap : %d bytes\n", buf, pcxl_res_size);
 568
 569         strcat(buf,  "            total:    free:    used:   % used:\n");
 570         sprintf(buf, "%sblocks  %8d %8ld %8ld %8ld%%\n", buf, pcxl_res_size,
 571                 pcxl_res_size - pcxl_used_bytes, pcxl_used_bytes,
 572                 (pcxl_used_bytes * 100) / pcxl_res_size);
 573
 574         sprintf(buf, "%spages   %8ld %8ld %8ld %8ld%%\n", buf, total_pages,
 575                 total_pages - pcxl_used_pages, pcxl_used_pages,
 576                 (pcxl_used_pages * 100 / total_pages));
 577
 578 #if 0
 579         strcat(buf, "\nResource bitmap:");
 580
 581         for(; i < (pcxl_res_size / sizeof(u_long)); ++i, ++res_ptr) {
 582                 if ((i & 7) == 0)
 583                     strcat(buf,"\n   ");
 584                 sprintf(buf, "%s %08lx", buf, *res_ptr);
 585         }
 586 #endif
 587         strcat(buf, "\n");
 588         return strlen(buf);
 589 }
 590