drivers/staging/comedi/drivers.c

   1 /*
   2     module/drivers.c
   3     functions for manipulating drivers
   4
   5     COMEDI - Linux Control and Measurement Device Interface
   6     Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License as published by
  10     the Free Software Foundation; either version 2 of the License, or
  11     (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License
  19     along with this program; if not, write to the Free Software
  20     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21
  22 */
  23
  24 #define _GNU_SOURCE
  25
  26 #define __NO_VERSION__
  27 #include "comedi_fops.h"
  28 #include <linux/device.h>
  29 #include <linux/module.h>
  30 #include <linux/pci.h>
  31 #include <linux/usb.h>
  32 #include <linux/errno.h>
  33 #include <linux/kernel.h>
  34 #include <linux/sched.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/delay.h>
  37 #include <linux/ioport.h>
  38 #include <linux/mm.h>
  39 #include <linux/slab.h>
  40 #include <linux/highmem.h>      /* for SuSE brokenness */
  41 #include <linux/vmalloc.h>
  42 #include <linux/cdev.h>
  43 #include <linux/dma-mapping.h>
  44 #include <linux/io.h>
  45 #include <asm/system.h>
  46
  47 #include "comedidev.h"
  48 #include "internal.h"
  49
  50 static int postconfig(struct comedi_device *dev);
  51 static int insn_rw_emulate_bits(struct comedi_device *dev,
  52                                 struct comedi_subdevice *s,
  53                                 struct comedi_insn *insn, unsigned int *data);
  54 static void *comedi_recognize(struct comedi_driver *driv, const char *name);
  55 static void comedi_report_boards(struct comedi_driver *driv);
  56 static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s);
  57
  58 struct comedi_driver *comedi_drivers;
  59
  60 static void cleanup_device(struct comedi_device *dev)
  61 {
  62         int i;
  63         struct comedi_subdevice *s;
  64
  65         if (dev->subdevices) {
  66                 for (i = 0; i < dev->n_subdevices; i++) {
  67                         s = dev->subdevices + i;
  68                         comedi_free_subdevice_minor(s);
  69                         if (s->async) {
  70                                 comedi_buf_alloc(dev, s, 0);
  71                                 kfree(s->async);
  72                         }
  73                 }
  74                 kfree(dev->subdevices);
  75                 dev->subdevices = NULL;
  76                 dev->n_subdevices = 0;
  77         }
  78         kfree(dev->private);
  79         dev->private = NULL;
  80         dev->driver = NULL;
  81         dev->board_name = NULL;
  82         dev->board_ptr = NULL;
  83         dev->iobase = 0;
  84         dev->irq = 0;
  85         dev->read_subdev = NULL;
  86         dev->write_subdev = NULL;
  87         dev->open = NULL;
  88         dev->close = NULL;
  89         comedi_set_hw_dev(dev, NULL);
  90 }
  91
  92 static void __comedi_device_detach(struct comedi_device *dev)
  93 {
  94         dev->attached = 0;
  95         if (dev->driver)
  96                 dev->driver->detach(dev);
  97         else
  98                 printk(KERN_WARNING "BUG: dev->driver=NULL in comedi_device_detach()\n");
  99         cleanup_device(dev);
 100 }
 101
 102 void comedi_device_detach(struct comedi_device *dev)
 103 {
 104         if (!dev->attached)
 105                 return;
 106         __comedi_device_detach(dev);
 107 }
 108
 109 int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 110 {
 111         struct comedi_driver *driv;
 112         int ret;
 113
 114         if (dev->attached)
 115                 return -EBUSY;
 116
 117         for (driv = comedi_drivers; driv; driv = driv->next) {
 118                 if (!try_module_get(driv->module)) {
 119                         printk
 120                             (KERN_INFO "comedi: failed to increment module count, skipping\n");
 121                         continue;
 122                 }
 123                 if (driv->num_names) {
 124                         dev->board_ptr = comedi_recognize(driv, it->board_name);
 125                         if (dev->board_ptr == NULL) {
 126                                 module_put(driv->module);
 127                                 continue;
 128                         }
 129                 } else {
 130                         if (strcmp(driv->driver_name, it->board_name)) {
 131                                 module_put(driv->module);
 132                                 continue;
 133                         }
 134                 }
 135                 /* initialize dev->driver here so
 136                  * comedi_error() can be called from attach */
 137                 dev->driver = driv;
 138                 ret = driv->attach(dev, it);
 139                 if (ret < 0) {
 140                         module_put(dev->driver->module);
 141                         __comedi_device_detach(dev);
 142                         return ret;
 143                 }
 144                 goto attached;
 145         }
 146
 147         /*  recognize has failed if we get here */
 148         /*  report valid board names before returning error */
 149         for (driv = comedi_drivers; driv; driv = driv->next) {
 150                 if (!try_module_get(driv->module)) {
 151                         printk(KERN_INFO "comedi: failed to increment module count\n");
 152                         continue;
 153                 }
 154                 comedi_report_boards(driv);
 155                 module_put(driv->module);
 156         }
 157         return -EIO;
 158
 159 attached:
 160         /* do a little post-config cleanup */
 161         ret = postconfig(dev);
 162         module_put(dev->driver->module);
 163         if (ret < 0) {
 164                 __comedi_device_detach(dev);
 165                 return ret;
 166         }
 167
 168         if (!dev->board_name) {
 169                 printk(KERN_WARNING "BUG: dev->board_name=<%p>\n",
 170                        dev->board_name);
 171                 dev->board_name = "BUG";
 172         }
 173         smp_wmb();
 174         dev->attached = 1;
 175
 176         return 0;
 177 }
 178
 179 int comedi_driver_register(struct comedi_driver *driver)
 180 {
 181         driver->next = comedi_drivers;
 182         comedi_drivers = driver;
 183
 184         return 0;
 185 }
 186 EXPORT_SYMBOL(comedi_driver_register);
 187
 188 int comedi_driver_unregister(struct comedi_driver *driver)
 189 {
 190         struct comedi_driver *prev;
 191         int i;
 192
 193         /* check for devices using this driver */
 194         for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
 195                 struct comedi_device_file_info *dev_file_info =
 196                     comedi_get_device_file_info(i);
 197                 struct comedi_device *dev;
 198
 199                 if (dev_file_info == NULL)
 200                         continue;
 201                 dev = dev_file_info->device;
 202
 203                 mutex_lock(&dev->mutex);
 204                 if (dev->attached && dev->driver == driver) {
 205                         if (dev->use_count)
 206                                 printk
 207                                     (KERN_WARNING "BUG! detaching device with use_count=%d\n",
 208                                      dev->use_count);
 209                         comedi_device_detach(dev);
 210                 }
 211                 mutex_unlock(&dev->mutex);
 212         }
 213
 214         if (comedi_drivers == driver) {
 215                 comedi_drivers = driver->next;
 216                 return 0;
 217         }
 218
 219         for (prev = comedi_drivers; prev->next; prev = prev->next) {
 220                 if (prev->next == driver) {
 221                         prev->next = driver->next;
 222                         return 0;
 223                 }
 224         }
 225         return -EINVAL;
 226 }
 227 EXPORT_SYMBOL(comedi_driver_unregister);
 228
 229 static int postconfig(struct comedi_device *dev)
 230 {
 231         int i;
 232         struct comedi_subdevice *s;
 233         struct comedi_async *async = NULL;
 234         int ret;
 235
 236         for (i = 0; i < dev->n_subdevices; i++) {
 237                 s = dev->subdevices + i;
 238
 239                 if (s->type == COMEDI_SUBD_UNUSED)
 240                         continue;
 241
 242                 if (s->len_chanlist == 0)
 243                         s->len_chanlist = 1;
 244
 245                 if (s->do_cmd) {
 246                         BUG_ON((s->subdev_flags & (SDF_CMD_READ |
 247                                                    SDF_CMD_WRITE)) == 0);
 248                         BUG_ON(!s->do_cmdtest);
 249
 250                         async =
 251                             kzalloc(sizeof(struct comedi_async), GFP_KERNEL);
 252                         if (async == NULL) {
 253                                 printk(KERN_INFO "failed to allocate async struct\n");
 254                                 return -ENOMEM;
 255                         }
 256                         init_waitqueue_head(&async->wait_head);
 257                         async->subdevice = s;
 258                         s->async = async;
 259
 260 #define DEFAULT_BUF_MAXSIZE (64*1024)
 261 #define DEFAULT_BUF_SIZE (64*1024)
 262
 263                         async->max_bufsize = DEFAULT_BUF_MAXSIZE;
 264
 265                         async->prealloc_buf = NULL;
 266                         async->prealloc_bufsz = 0;
 267                         if (comedi_buf_alloc(dev, s, DEFAULT_BUF_SIZE) < 0) {
 268                                 printk(KERN_INFO "Buffer allocation failed\n");
 269                                 return -ENOMEM;
 270                         }
 271                         if (s->buf_change) {
 272                                 ret = s->buf_change(dev, s, DEFAULT_BUF_SIZE);
 273                                 if (ret < 0)
 274                                         return ret;
 275                         }
 276                         comedi_alloc_subdevice_minor(dev, s);
 277                 }
 278
 279                 if (!s->range_table && !s->range_table_list)
 280                         s->range_table = &range_unknown;
 281
 282                 if (!s->insn_read && s->insn_bits)
 283                         s->insn_read = insn_rw_emulate_bits;
 284                 if (!s->insn_write && s->insn_bits)
 285                         s->insn_write = insn_rw_emulate_bits;
 286
 287                 if (!s->insn_read)
 288                         s->insn_read = insn_inval;
 289                 if (!s->insn_write)
 290                         s->insn_write = insn_inval;
 291                 if (!s->insn_bits)
 292                         s->insn_bits = insn_inval;
 293                 if (!s->insn_config)
 294                         s->insn_config = insn_inval;
 295
 296                 if (!s->poll)
 297                         s->poll = poll_invalid;
 298         }
 299
 300         return 0;
 301 }
 302
 303 /* generic recognize function for drivers
 304  * that register their supported board names */
 305 static void *comedi_recognize(struct comedi_driver *driv, const char *name)
 306 {
 307         unsigned i;
 308         const char *const *name_ptr = driv->board_name;
 309         for (i = 0; i < driv->num_names; i++) {
 310                 if (strcmp(*name_ptr, name) == 0)
 311                         return (void *)name_ptr;
 312                 name_ptr =
 313                     (const char *const *)((const char *)name_ptr +
 314                                           driv->offset);
 315         }
 316
 317         return NULL;
 318 }
 319
 320 static void comedi_report_boards(struct comedi_driver *driv)
 321 {
 322         unsigned int i;
 323         const char *const *name_ptr;
 324
 325         printk(KERN_INFO "comedi: valid board names for %s driver are:\n",
 326                driv->driver_name);
 327
 328         name_ptr = driv->board_name;
 329         for (i = 0; i < driv->num_names; i++) {
 330                 printk(KERN_INFO " %s\n", *name_ptr);
 331                 name_ptr = (const char **)((char *)name_ptr + driv->offset);
 332         }
 333
 334         if (driv->num_names == 0)
 335                 printk(KERN_INFO " %s\n", driv->driver_name);
 336 }
 337
 338 static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s)
 339 {
 340         return -EINVAL;
 341 }
 342
 343 int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s,
 344                struct comedi_insn *insn, unsigned int *data)
 345 {
 346         return -EINVAL;
 347 }
 348
 349 static int insn_rw_emulate_bits(struct comedi_device *dev,
 350                                 struct comedi_subdevice *s,
 351                                 struct comedi_insn *insn, unsigned int *data)
 352 {
 353         struct comedi_insn new_insn;
 354         int ret;
 355         static const unsigned channels_per_bitfield = 32;
 356
 357         unsigned chan = CR_CHAN(insn->chanspec);
 358         const unsigned base_bitfield_channel =
 359             (chan < channels_per_bitfield) ? 0 : chan;
 360         unsigned int new_data[2];
 361         memset(new_data, 0, sizeof(new_data));
 362         memset(&new_insn, 0, sizeof(new_insn));
 363         new_insn.insn = INSN_BITS;
 364         new_insn.chanspec = base_bitfield_channel;
 365         new_insn.n = 2;
 366         new_insn.data = new_data;
 367         new_insn.subdev = insn->subdev;
 368
 369         if (insn->insn == INSN_WRITE) {
 370                 if (!(s->subdev_flags & SDF_WRITABLE))
 371                         return -EINVAL;
 372                 new_data[0] = 1 << (chan - base_bitfield_channel); /* mask */
 373                 new_data[1] = data[0] ? (1 << (chan - base_bitfield_channel))
 374                               : 0; /* bits */
 375         }
 376
 377         ret = s->insn_bits(dev, s, &new_insn, new_data);
 378         if (ret < 0)
 379                 return ret;
 380
 381         if (insn->insn == INSN_READ)
 382                 data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1;
 383
 384         return 1;
 385 }
 386
 387 static inline unsigned long uvirt_to_kva(pgd_t *pgd, unsigned long adr)
 388 {
 389         unsigned long ret = 0UL;
 390         pmd_t *pmd;
 391         pte_t *ptep, pte;
 392         pud_t *pud;
 393
 394         if (!pgd_none(*pgd)) {
 395                 pud = pud_offset(pgd, adr);
 396                 pmd = pmd_offset(pud, adr);
 397                 if (!pmd_none(*pmd)) {
 398                         ptep = pte_offset_kernel(pmd, adr);
 399                         pte = *ptep;
 400                         if (pte_present(pte)) {
 401                                 ret = (unsigned long)
 402                                     page_address(pte_page(pte));
 403                                 ret |= (adr & (PAGE_SIZE - 1));
 404                         }
 405                 }
 406         }
 407         return ret;
 408 }
 409
 410 static inline unsigned long kvirt_to_kva(unsigned long adr)
 411 {
 412         unsigned long va, kva;
 413
 414         va = adr;
 415         kva = uvirt_to_kva(pgd_offset_k(va), va);
 416
 417         return kva;
 418 }
 419
 420 int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
 421                      unsigned long new_size)
 422 {
 423         struct comedi_async *async = s->async;
 424
 425         /* Round up new_size to multiple of PAGE_SIZE */
 426         new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
 427
 428         /* if no change is required, do nothing */
 429         if (async->prealloc_buf && async->prealloc_bufsz == new_size)
 430                 return 0;
 431
 432         /*  deallocate old buffer */
 433         if (async->prealloc_buf) {
 434                 vunmap(async->prealloc_buf);
 435                 async->prealloc_buf = NULL;
 436                 async->prealloc_bufsz = 0;
 437         }
 438         if (async->buf_page_list) {
 439                 unsigned i;
 440                 for (i = 0; i < async->n_buf_pages; ++i) {
 441                         if (async->buf_page_list[i].virt_addr) {
 442                                 clear_bit(PG_reserved, &(virt_to_page(async->buf_page_list[i].virt_addr)->flags));
 443                                 if (s->async_dma_dir != DMA_NONE) {
 444                                         dma_free_coherent(dev->hw_dev,
 445                                                           PAGE_SIZE,
 446                                                           async->
 447                                                           buf_page_list
 448                                                           [i].virt_addr,
 449                                                           async->
 450                                                           buf_page_list
 451                                                           [i].dma_addr);
 452                                 } else {
 453                                         free_page((unsigned long)
 454                                                   async->buf_page_list[i].
 455                                                   virt_addr);
 456                                 }
 457                         }
 458                 }
 459                 vfree(async->buf_page_list);
 460                 async->buf_page_list = NULL;
 461                 async->n_buf_pages = 0;
 462         }
 463         /*  allocate new buffer */
 464         if (new_size) {
 465                 unsigned i = 0;
 466                 unsigned n_pages = new_size >> PAGE_SHIFT;
 467                 struct page **pages = NULL;
 468
 469                 async->buf_page_list =
 470                     vmalloc(sizeof(struct comedi_buf_page) * n_pages);
 471                 if (async->buf_page_list) {
 472                         memset(async->buf_page_list, 0,
 473                                sizeof(struct comedi_buf_page) * n_pages);
 474                         pages = vmalloc(sizeof(struct page *) * n_pages);
 475                 }
 476                 if (pages) {
 477                         for (i = 0; i < n_pages; i++) {
 478                                 if (s->async_dma_dir != DMA_NONE) {
 479                                         async->buf_page_list[i].virt_addr =
 480                                             dma_alloc_coherent(dev->hw_dev,
 481                                                                PAGE_SIZE,
 482                                                                &async->
 483                                                                buf_page_list
 484                                                                [i].dma_addr,
 485                                                                GFP_KERNEL |
 486                                                                __GFP_COMP);
 487                                 } else {
 488                                         async->buf_page_list[i].virt_addr =
 489                                             (void *)
 490                                             get_zeroed_page(GFP_KERNEL);
 491                                 }
 492                                 if (async->buf_page_list[i].virt_addr == NULL)
 493                                         break;
 494
 495                                 set_bit(PG_reserved,
 496                                         &(virt_to_page(async->buf_page_list[i].virt_addr)->flags));
 497                                 pages[i] = virt_to_page(async->buf_page_list[i].virt_addr);
 498                         }
 499                 }
 500                 if (i == n_pages) {
 501                         async->prealloc_buf =
 502                             vmap(pages, n_pages, VM_MAP, PAGE_KERNEL_NOCACHE);
 503                 }
 504                 vfree(pages);
 505
 506                 if (async->prealloc_buf == NULL) {
 507                         /* Some allocation failed above. */
 508                         if (async->buf_page_list) {
 509                                 for (i = 0; i < n_pages; i++) {
 510                                         if (async->buf_page_list[i].virt_addr ==
 511                                             NULL) {
 512                                                 break;
 513                                         }
 514                                         clear_bit(PG_reserved, &(virt_to_page(async->buf_page_list[i].virt_addr)->flags));
 515                                         if (s->async_dma_dir != DMA_NONE) {
 516                                                 dma_free_coherent(dev->hw_dev,
 517                                                                   PAGE_SIZE,
 518                                                                   async->
 519                                                                   buf_page_list
 520                                                                   [i].virt_addr,
 521                                                                   async->
 522                                                                   buf_page_list
 523                                                                   [i].dma_addr);
 524                                         } else {
 525                                                 free_page((unsigned long)
 526                                                           async->buf_page_list
 527                                                           [i].virt_addr);
 528                                         }
 529                                 }
 530                                 vfree(async->buf_page_list);
 531                                 async->buf_page_list = NULL;
 532                         }
 533                         return -ENOMEM;
 534                 }
 535                 async->n_buf_pages = n_pages;
 536         }
 537         async->prealloc_bufsz = new_size;
 538
 539         return 0;
 540 }
 541
 542 /* munging is applied to data by core as it passes between user
 543  * and kernel space */
 544 static unsigned int comedi_buf_munge(struct comedi_async *async,
 545                                      unsigned int num_bytes)
 546 {
 547         struct comedi_subdevice *s = async->subdevice;
 548         unsigned int count = 0;
 549         const unsigned num_sample_bytes = bytes_per_sample(s);
 550
 551         if (s->munge == NULL || (async->cmd.flags & CMDF_RAWDATA)) {
 552                 async->munge_count += num_bytes;
 553                 BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
 554                 return num_bytes;
 555         }
 556         /* don't munge partial samples */
 557         num_bytes -= num_bytes % num_sample_bytes;
 558         while (count < num_bytes) {
 559                 int block_size;
 560
 561                 block_size = num_bytes - count;
 562                 if (block_size < 0) {
 563                         printk(KERN_WARNING "%s: %s: bug! block_size is negative\n",
 564                                __FILE__, __func__);
 565                         break;
 566                 }
 567                 if ((int)(async->munge_ptr + block_size -
 568                           async->prealloc_bufsz) > 0)
 569                         block_size = async->prealloc_bufsz - async->munge_ptr;
 570
 571                 s->munge(s->device, s, async->prealloc_buf + async->munge_ptr,
 572                          block_size, async->munge_chan);
 573
 574                 smp_wmb();      /* barrier insures data is munged in buffer
 575                                  * before munge_count is incremented */
 576
 577                 async->munge_chan += block_size / num_sample_bytes;
 578                 async->munge_chan %= async->cmd.chanlist_len;
 579                 async->munge_count += block_size;
 580                 async->munge_ptr += block_size;
 581                 async->munge_ptr %= async->prealloc_bufsz;
 582                 count += block_size;
 583         }
 584         BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
 585         return count;
 586 }
 587
 588 unsigned int comedi_buf_write_n_available(struct comedi_async *async)
 589 {
 590         unsigned int free_end;
 591         unsigned int nbytes;
 592
 593         if (async == NULL)
 594                 return 0;
 595
 596         free_end = async->buf_read_count + async->prealloc_bufsz;
 597         nbytes = free_end - async->buf_write_alloc_count;
 598         nbytes -= nbytes % bytes_per_sample(async->subdevice);
 599         /* barrier insures the read of buf_read_count in this
 600            query occurs before any following writes to the buffer which
 601            might be based on the return value from this query.
 602          */
 603         smp_mb();
 604         return nbytes;
 605 }
 606
 607 /* allocates chunk for the writer from free buffer space */
 608 unsigned int comedi_buf_write_alloc(struct comedi_async *async,
 609                                     unsigned int nbytes)
 610 {
 611         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 612
 613         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0)
 614                 nbytes = free_end - async->buf_write_alloc_count;
 615
 616         async->buf_write_alloc_count += nbytes;
 617         /* barrier insures the read of buf_read_count above occurs before
 618            we write data to the write-alloc'ed buffer space */
 619         smp_mb();
 620         return nbytes;
 621 }
 622 EXPORT_SYMBOL(comedi_buf_write_alloc);
 623
 624 /* allocates nothing unless it can completely fulfill the request */
 625 unsigned int comedi_buf_write_alloc_strict(struct comedi_async *async,
 626                                            unsigned int nbytes)
 627 {
 628         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 629
 630         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0)
 631                 nbytes = 0;
 632
 633         async->buf_write_alloc_count += nbytes;
 634         /* barrier insures the read of buf_read_count above occurs before
 635            we write data to the write-alloc'ed buffer space */
 636         smp_mb();
 637         return nbytes;
 638 }
 639
 640 /* transfers a chunk from writer to filled buffer space */
 641 unsigned comedi_buf_write_free(struct comedi_async *async, unsigned int nbytes)
 642 {
 643         if ((int)(async->buf_write_count + nbytes -
 644                   async->buf_write_alloc_count) > 0) {
 645                 printk
 646                     (KERN_INFO "comedi: attempted to write-free more bytes than have been write-allocated.\n");
 647                 nbytes = async->buf_write_alloc_count - async->buf_write_count;
 648         }
 649         async->buf_write_count += nbytes;
 650         async->buf_write_ptr += nbytes;
 651         comedi_buf_munge(async, async->buf_write_count - async->munge_count);
 652         if (async->buf_write_ptr >= async->prealloc_bufsz)
 653                 async->buf_write_ptr %= async->prealloc_bufsz;
 654
 655         return nbytes;
 656 }
 657 EXPORT_SYMBOL(comedi_buf_write_free);
 658
 659 /* allocates a chunk for the reader from filled (and munged) buffer space */
 660 unsigned comedi_buf_read_alloc(struct comedi_async *async, unsigned nbytes)
 661 {
 662         if ((int)(async->buf_read_alloc_count + nbytes - async->munge_count) >
 663             0) {
 664                 nbytes = async->munge_count - async->buf_read_alloc_count;
 665         }
 666         async->buf_read_alloc_count += nbytes;
 667         /* barrier insures read of munge_count occurs before we actually read
 668            data out of buffer */
 669         smp_rmb();
 670         return nbytes;
 671 }
 672 EXPORT_SYMBOL(comedi_buf_read_alloc);
 673
 674 /* transfers control of a chunk from reader to free buffer space */
 675 unsigned comedi_buf_read_free(struct comedi_async *async, unsigned int nbytes)
 676 {
 677         /* barrier insures data has been read out of
 678          * buffer before read count is incremented */
 679         smp_mb();
 680         if ((int)(async->buf_read_count + nbytes -
 681                   async->buf_read_alloc_count) > 0) {
 682                 printk
 683                     ("comedi: attempted to read-free more bytes than have been read-allocated.\n");
 684                 nbytes = async->buf_read_alloc_count - async->buf_read_count;
 685         }
 686         async->buf_read_count += nbytes;
 687         async->buf_read_ptr += nbytes;
 688         async->buf_read_ptr %= async->prealloc_bufsz;
 689         return nbytes;
 690 }
 691 EXPORT_SYMBOL(comedi_buf_read_free);
 692
 693 void comedi_buf_memcpy_to(struct comedi_async *async, unsigned int offset,
 694                           const void *data, unsigned int num_bytes)
 695 {
 696         unsigned int write_ptr = async->buf_write_ptr + offset;
 697
 698         if (write_ptr >= async->prealloc_bufsz)
 699                 write_ptr %= async->prealloc_bufsz;
 700
 701         while (num_bytes) {
 702                 unsigned int block_size;
 703
 704                 if (write_ptr + num_bytes > async->prealloc_bufsz)
 705                         block_size = async->prealloc_bufsz - write_ptr;
 706                 else
 707                         block_size = num_bytes;
 708
 709                 memcpy(async->prealloc_buf + write_ptr, data, block_size);
 710
 711                 data += block_size;
 712                 num_bytes -= block_size;
 713
 714                 write_ptr = 0;
 715         }
 716 }
 717 EXPORT_SYMBOL(comedi_buf_memcpy_to);
 718
 719 void comedi_buf_memcpy_from(struct comedi_async *async, unsigned int offset,
 720                             void *dest, unsigned int nbytes)
 721 {
 722         void *src;
 723         unsigned int read_ptr = async->buf_read_ptr + offset;
 724
 725         if (read_ptr >= async->prealloc_bufsz)
 726                 read_ptr %= async->prealloc_bufsz;
 727
 728         while (nbytes) {
 729                 unsigned int block_size;
 730
 731                 src = async->prealloc_buf + read_ptr;
 732
 733                 if (nbytes >= async->prealloc_bufsz - read_ptr)
 734                         block_size = async->prealloc_bufsz - read_ptr;
 735                 else
 736                         block_size = nbytes;
 737
 738                 memcpy(dest, src, block_size);
 739                 nbytes -= block_size;
 740                 dest += block_size;
 741                 read_ptr = 0;
 742         }
 743 }
 744 EXPORT_SYMBOL(comedi_buf_memcpy_from);
 745
 746 unsigned int comedi_buf_read_n_available(struct comedi_async *async)
 747 {
 748         unsigned num_bytes;
 749
 750         if (async == NULL)
 751                 return 0;
 752         num_bytes = async->munge_count - async->buf_read_count;
 753         /* barrier insures the read of munge_count in this
 754            query occurs before any following reads of the buffer which
 755            might be based on the return value from this query.
 756          */
 757         smp_rmb();
 758         return num_bytes;
 759 }
 760 EXPORT_SYMBOL(comedi_buf_read_n_available);
 761
 762 int comedi_buf_get(struct comedi_async *async, short *x)
 763 {
 764         unsigned int n = comedi_buf_read_n_available(async);
 765
 766         if (n < sizeof(short))
 767                 return 0;
 768         comedi_buf_read_alloc(async, sizeof(short));
 769         *x = *(short *)(async->prealloc_buf + async->buf_read_ptr);
 770         comedi_buf_read_free(async, sizeof(short));
 771         return 1;
 772 }
 773 EXPORT_SYMBOL(comedi_buf_get);
 774
 775 int comedi_buf_put(struct comedi_async *async, short x)
 776 {
 777         unsigned int n = comedi_buf_write_alloc_strict(async, sizeof(short));
 778
 779         if (n < sizeof(short)) {
 780                 async->events |= COMEDI_CB_ERROR;
 781                 return 0;
 782         }
 783         *(short *)(async->prealloc_buf + async->buf_write_ptr) = x;
 784         comedi_buf_write_free(async, sizeof(short));
 785         return 1;
 786 }
 787 EXPORT_SYMBOL(comedi_buf_put);
 788
 789 void comedi_reset_async_buf(struct comedi_async *async)
 790 {
 791         async->buf_write_alloc_count = 0;
 792         async->buf_write_count = 0;
 793         async->buf_read_alloc_count = 0;
 794         async->buf_read_count = 0;
 795
 796         async->buf_write_ptr = 0;
 797         async->buf_read_ptr = 0;
 798
 799         async->cur_chan = 0;
 800         async->scan_progress = 0;
 801         async->munge_chan = 0;
 802         async->munge_count = 0;
 803         async->munge_ptr = 0;
 804
 805         async->events = 0;
 806 }
 807
 808 static int comedi_auto_config(struct device *hardware_device,
 809                               const char *board_name, const int *options,
 810                               unsigned num_options)
 811 {
 812         struct comedi_devconfig it;
 813         int minor;
 814         struct comedi_device_file_info *dev_file_info;
 815         int retval;
 816         unsigned *private_data = NULL;
 817
 818         if (!comedi_autoconfig) {
 819                 dev_set_drvdata(hardware_device, NULL);
 820                 return 0;
 821         }
 822
 823         minor = comedi_alloc_board_minor(hardware_device);
 824         if (minor < 0)
 825                 return minor;
 826
 827         private_data = kmalloc(sizeof(unsigned), GFP_KERNEL);
 828         if (private_data == NULL) {
 829                 retval = -ENOMEM;
 830                 goto cleanup;
 831         }
 832         *private_data = minor;
 833         dev_set_drvdata(hardware_device, private_data);
 834
 835         dev_file_info = comedi_get_device_file_info(minor);
 836
 837         memset(&it, 0, sizeof(it));
 838         strncpy(it.board_name, board_name, COMEDI_NAMELEN);
 839         it.board_name[COMEDI_NAMELEN - 1] = '\0';
 840         BUG_ON(num_options > COMEDI_NDEVCONFOPTS);
 841         memcpy(it.options, options, num_options * sizeof(int));
 842
 843         mutex_lock(&dev_file_info->device->mutex);
 844         retval = comedi_device_attach(dev_file_info->device, &it);
 845         mutex_unlock(&dev_file_info->device->mutex);
 846
 847 cleanup:
 848         if (retval < 0) {
 849                 kfree(private_data);
 850                 comedi_free_board_minor(minor);
 851         }
 852         return retval;
 853 }
 854
 855 static void comedi_auto_unconfig(struct device *hardware_device)
 856 {
 857         unsigned *minor = (unsigned *)dev_get_drvdata(hardware_device);
 858         if (minor == NULL)
 859                 return;
 860
 861         BUG_ON(*minor >= COMEDI_NUM_BOARD_MINORS);
 862
 863         comedi_free_board_minor(*minor);
 864         dev_set_drvdata(hardware_device, NULL);
 865         kfree(minor);
 866 }
 867
 868 int comedi_pci_auto_config(struct pci_dev *pcidev, const char *board_name)
 869 {
 870         int options[2];
 871
 872         /*  pci bus */
 873         options[0] = pcidev->bus->number;
 874         /*  pci slot */
 875         options[1] = PCI_SLOT(pcidev->devfn);
 876
 877         return comedi_auto_config(&pcidev->dev, board_name,
 878                                   options, ARRAY_SIZE(options));
 879 }
 880 EXPORT_SYMBOL_GPL(comedi_pci_auto_config);
 881
 882 void comedi_pci_auto_unconfig(struct pci_dev *pcidev)
 883 {
 884         comedi_auto_unconfig(&pcidev->dev);
 885 }
 886 EXPORT_SYMBOL_GPL(comedi_pci_auto_unconfig);
 887
 888 int comedi_usb_auto_config(struct usb_device *usbdev, const char *board_name)
 889 {
 890         BUG_ON(usbdev == NULL);
 891         return comedi_auto_config(&usbdev->dev, board_name, NULL, 0);
 892 }
 893 EXPORT_SYMBOL_GPL(comedi_usb_auto_config);
 894
 895 void comedi_usb_auto_unconfig(struct usb_device *usbdev)
 896 {
 897         BUG_ON(usbdev == NULL);
 898         comedi_auto_unconfig(&usbdev->dev);
 899 }
 900 EXPORT_SYMBOL_GPL(comedi_usb_auto_unconfig);