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
  99                        "BUG: dev->driver=NULL in comedi_device_detach()\n");
 100         cleanup_device(dev);
 101 }
 102
 103 void comedi_device_detach(struct comedi_device *dev)
 104 {
 105         if (!dev->attached)
 106                 return;
 107         __comedi_device_detach(dev);
 108 }
 109
 110 int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 111 {
 112         struct comedi_driver *driv;
 113         int ret;
 114
 115         if (dev->attached)
 116                 return -EBUSY;
 117
 118         for (driv = comedi_drivers; driv; driv = driv->next) {
 119                 if (!try_module_get(driv->module)) {
 120                         printk(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
 152                                "comedi: failed to increment module count\n");
 153                         continue;
 154                 }
 155                 comedi_report_boards(driv);
 156                 module_put(driv->module);
 157         }
 158         return -EIO;
 159
 160 attached:
 161         /* do a little post-config cleanup */
 162         ret = postconfig(dev);
 163         module_put(dev->driver->module);
 164         if (ret < 0) {
 165                 __comedi_device_detach(dev);
 166                 return ret;
 167         }
 168
 169         if (!dev->board_name) {
 170                 printk(KERN_WARNING "BUG: dev->board_name=<%p>\n",
 171                        dev->board_name);
 172                 dev->board_name = "BUG";
 173         }
 174         smp_wmb();
 175         dev->attached = 1;
 176
 177         return 0;
 178 }
 179
 180 int comedi_driver_register(struct comedi_driver *driver)
 181 {
 182         driver->next = comedi_drivers;
 183         comedi_drivers = driver;
 184
 185         return 0;
 186 }
 187 EXPORT_SYMBOL(comedi_driver_register);
 188
 189 int comedi_driver_unregister(struct comedi_driver *driver)
 190 {
 191         struct comedi_driver *prev;
 192         int i;
 193
 194         /* check for devices using this driver */
 195         for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
 196                 struct comedi_device_file_info *dev_file_info =
 197                     comedi_get_device_file_info(i);
 198                 struct comedi_device *dev;
 199
 200                 if (dev_file_info == NULL)
 201                         continue;
 202                 dev = dev_file_info->device;
 203
 204                 mutex_lock(&dev->mutex);
 205                 if (dev->attached && dev->driver == driver) {
 206                         if (dev->use_count)
 207                                 printk(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
 254                                        "failed to allocate async struct\n");
 255                                 return -ENOMEM;
 256                         }
 257                         init_waitqueue_head(&async->wait_head);
 258                         async->subdevice = s;
 259                         s->async = async;
 260
 261 #define DEFAULT_BUF_MAXSIZE (64*1024)
 262 #define DEFAULT_BUF_SIZE (64*1024)
 263
 264                         async->max_bufsize = DEFAULT_BUF_MAXSIZE;
 265
 266                         async->prealloc_buf = NULL;
 267                         async->prealloc_bufsz = 0;
 268                         if (comedi_buf_alloc(dev, s, DEFAULT_BUF_SIZE) < 0) {
 269                                 printk(KERN_INFO "Buffer allocation failed\n");
 270                                 return -ENOMEM;
 271                         }
 272                         if (s->buf_change) {
 273                                 ret = s->buf_change(dev, s, DEFAULT_BUF_SIZE);
 274                                 if (ret < 0)
 275                                         return ret;
 276                         }
 277                         comedi_alloc_subdevice_minor(dev, s);
 278                 }
 279
 280                 if (!s->range_table && !s->range_table_list)
 281                         s->range_table = &range_unknown;
 282
 283                 if (!s->insn_read && s->insn_bits)
 284                         s->insn_read = insn_rw_emulate_bits;
 285                 if (!s->insn_write && s->insn_bits)
 286                         s->insn_write = insn_rw_emulate_bits;
 287
 288                 if (!s->insn_read)
 289                         s->insn_read = insn_inval;
 290                 if (!s->insn_write)
 291                         s->insn_write = insn_inval;
 292                 if (!s->insn_bits)
 293                         s->insn_bits = insn_inval;
 294                 if (!s->insn_config)
 295                         s->insn_config = insn_inval;
 296
 297                 if (!s->poll)
 298                         s->poll = poll_invalid;
 299         }
 300
 301         return 0;
 302 }
 303
 304 /* generic recognize function for drivers
 305  * that register their supported board names */
 306 static void *comedi_recognize(struct comedi_driver *driv, const char *name)
 307 {
 308         unsigned i;
 309         const char *const *name_ptr = driv->board_name;
 310         for (i = 0; i < driv->num_names; i++) {
 311                 if (strcmp(*name_ptr, name) == 0)
 312                         return (void *)name_ptr;
 313                 name_ptr =
 314                     (const char *const *)((const char *)name_ptr +
 315                                           driv->offset);
 316         }
 317
 318         return NULL;
 319 }
 320
 321 static void comedi_report_boards(struct comedi_driver *driv)
 322 {
 323         unsigned int i;
 324         const char *const *name_ptr;
 325
 326         printk(KERN_INFO "comedi: valid board names for %s driver are:\n",
 327                driv->driver_name);
 328
 329         name_ptr = driv->board_name;
 330         for (i = 0; i < driv->num_names; i++) {
 331                 printk(KERN_INFO " %s\n", *name_ptr);
 332                 name_ptr = (const char **)((char *)name_ptr + driv->offset);
 333         }
 334
 335         if (driv->num_names == 0)
 336                 printk(KERN_INFO " %s\n", driv->driver_name);
 337 }
 338
 339 static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s)
 340 {
 341         return -EINVAL;
 342 }
 343
 344 int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s,
 345                struct comedi_insn *insn, unsigned int *data)
 346 {
 347         return -EINVAL;
 348 }
 349
 350 static int insn_rw_emulate_bits(struct comedi_device *dev,
 351                                 struct comedi_subdevice *s,
 352                                 struct comedi_insn *insn, unsigned int *data)
 353 {
 354         struct comedi_insn new_insn;
 355         int ret;
 356         static const unsigned channels_per_bitfield = 32;
 357
 358         unsigned chan = CR_CHAN(insn->chanspec);
 359         const unsigned base_bitfield_channel =
 360             (chan < channels_per_bitfield) ? 0 : chan;
 361         unsigned int new_data[2];
 362         memset(new_data, 0, sizeof(new_data));
 363         memset(&new_insn, 0, sizeof(new_insn));
 364         new_insn.insn = INSN_BITS;
 365         new_insn.chanspec = base_bitfield_channel;
 366         new_insn.n = 2;
 367         new_insn.data = new_data;
 368         new_insn.subdev = insn->subdev;
 369
 370         if (insn->insn == INSN_WRITE) {
 371                 if (!(s->subdev_flags & SDF_WRITABLE))
 372                         return -EINVAL;
 373                 new_data[0] = 1 << (chan - base_bitfield_channel); /* mask */
 374                 new_data[1] = data[0] ? (1 << (chan - base_bitfield_channel))
 375                               : 0; /* bits */
 376         }
 377
 378         ret = s->insn_bits(dev, s, &new_insn, new_data);
 379         if (ret < 0)
 380                 return ret;
 381
 382         if (insn->insn == INSN_READ)
 383                 data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1;
 384
 385         return 1;
 386 }
 387
 388 static inline unsigned long uvirt_to_kva(pgd_t *pgd, unsigned long adr)
 389 {
 390         unsigned long ret = 0UL;
 391         pmd_t *pmd;
 392         pte_t *ptep, pte;
 393         pud_t *pud;
 394
 395         if (!pgd_none(*pgd)) {
 396                 pud = pud_offset(pgd, adr);
 397                 pmd = pmd_offset(pud, adr);
 398                 if (!pmd_none(*pmd)) {
 399                         ptep = pte_offset_kernel(pmd, adr);
 400                         pte = *ptep;
 401                         if (pte_present(pte)) {
 402                                 ret = (unsigned long)
 403                                     page_address(pte_page(pte));
 404                                 ret |= (adr & (PAGE_SIZE - 1));
 405                         }
 406                 }
 407         }
 408         return ret;
 409 }
 410
 411 static inline unsigned long kvirt_to_kva(unsigned long adr)
 412 {
 413         unsigned long va, kva;
 414
 415         va = adr;
 416         kva = uvirt_to_kva(pgd_offset_k(va), va);
 417
 418         return kva;
 419 }
 420
 421 int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
 422                      unsigned long new_size)
 423 {
 424         struct comedi_async *async = s->async;
 425
 426         /* Round up new_size to multiple of PAGE_SIZE */
 427         new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
 428
 429         /* if no change is required, do nothing */
 430         if (async->prealloc_buf && async->prealloc_bufsz == new_size)
 431                 return 0;
 432
 433         /*  deallocate old buffer */
 434         if (async->prealloc_buf) {
 435                 vunmap(async->prealloc_buf);
 436                 async->prealloc_buf = NULL;
 437                 async->prealloc_bufsz = 0;
 438         }
 439         if (async->buf_page_list) {
 440                 unsigned i;
 441                 for (i = 0; i < async->n_buf_pages; ++i) {
 442                         if (async->buf_page_list[i].virt_addr) {
 443                                 clear_bit(PG_reserved,
 444                                         &(virt_to_page(async->buf_page_list[i].
 445                                                         virt_addr)->flags));
 446                                 if (s->async_dma_dir != DMA_NONE) {
 447                                         dma_free_coherent(dev->hw_dev,
 448                                                           PAGE_SIZE,
 449                                                           async->
 450                                                           buf_page_list
 451                                                           [i].virt_addr,
 452                                                           async->
 453                                                           buf_page_list
 454                                                           [i].dma_addr);
 455                                 } else {
 456                                         free_page((unsigned long)
 457                                                   async->buf_page_list[i].
 458                                                   virt_addr);
 459                                 }
 460                         }
 461                 }
 462                 vfree(async->buf_page_list);
 463                 async->buf_page_list = NULL;
 464                 async->n_buf_pages = 0;
 465         }
 466         /*  allocate new buffer */
 467         if (new_size) {
 468                 unsigned i = 0;
 469                 unsigned n_pages = new_size >> PAGE_SHIFT;
 470                 struct page **pages = NULL;
 471
 472                 async->buf_page_list =
 473                     vzalloc(sizeof(struct comedi_buf_page) * n_pages);
 474                 if (async->buf_page_list)
 475                         pages = vmalloc(sizeof(struct page *) * n_pages);
 476
 477                 if (pages) {
 478                         for (i = 0; i < n_pages; i++) {
 479                                 if (s->async_dma_dir != DMA_NONE) {
 480                                         async->buf_page_list[i].virt_addr =
 481                                             dma_alloc_coherent(dev->hw_dev,
 482                                                                PAGE_SIZE,
 483                                                                &async->
 484                                                                buf_page_list
 485                                                                [i].dma_addr,
 486                                                                GFP_KERNEL |
 487                                                                __GFP_COMP);
 488                                 } else {
 489                                         async->buf_page_list[i].virt_addr =
 490                                             (void *)
 491                                             get_zeroed_page(GFP_KERNEL);
 492                                 }
 493                                 if (async->buf_page_list[i].virt_addr == NULL)
 494                                         break;
 495
 496                                 set_bit(PG_reserved,
 497                                         &(virt_to_page(async->buf_page_list[i].
 498                                                         virt_addr)->flags));
 499                                 pages[i] = virt_to_page(async->buf_page_list[i].
 500                                                                 virt_addr);
 501                         }
 502                 }
 503                 if (i == n_pages) {
 504                         async->prealloc_buf =
 505                             vmap(pages, n_pages, VM_MAP, PAGE_KERNEL_NOCACHE);
 506                 }
 507                 vfree(pages);
 508
 509                 if (async->prealloc_buf == NULL) {
 510                         /* Some allocation failed above. */
 511                         if (async->buf_page_list) {
 512                                 for (i = 0; i < n_pages; i++) {
 513                                         if (async->buf_page_list[i].virt_addr ==
 514                                             NULL) {
 515                                                 break;
 516                                         }
 517                                         clear_bit(PG_reserved,
 518                                                 &(virt_to_page(async->
 519                                                         buf_page_list[i].
 520                                                         virt_addr)->flags));
 521                                         if (s->async_dma_dir != DMA_NONE) {
 522                                                 dma_free_coherent(dev->hw_dev,
 523                                                                   PAGE_SIZE,
 524                                                                   async->
 525                                                                   buf_page_list
 526                                                                   [i].virt_addr,
 527                                                                   async->
 528                                                                   buf_page_list
 529                                                                   [i].dma_addr);
 530                                         } else {
 531                                                 free_page((unsigned long)
 532                                                           async->buf_page_list
 533                                                           [i].virt_addr);
 534                                         }
 535                                 }
 536                                 vfree(async->buf_page_list);
 537                                 async->buf_page_list = NULL;
 538                         }
 539                         return -ENOMEM;
 540                 }
 541                 async->n_buf_pages = n_pages;
 542         }
 543         async->prealloc_bufsz = new_size;
 544
 545         return 0;
 546 }
 547
 548 /* munging is applied to data by core as it passes between user
 549  * and kernel space */
 550 static unsigned int comedi_buf_munge(struct comedi_async *async,
 551                                      unsigned int num_bytes)
 552 {
 553         struct comedi_subdevice *s = async->subdevice;
 554         unsigned int count = 0;
 555         const unsigned num_sample_bytes = bytes_per_sample(s);
 556
 557         if (s->munge == NULL || (async->cmd.flags & CMDF_RAWDATA)) {
 558                 async->munge_count += num_bytes;
 559                 BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
 560                 return num_bytes;
 561         }
 562         /* don't munge partial samples */
 563         num_bytes -= num_bytes % num_sample_bytes;
 564         while (count < num_bytes) {
 565                 int block_size;
 566
 567                 block_size = num_bytes - count;
 568                 if (block_size < 0) {
 569                         printk(KERN_WARNING
 570                                "%s: %s: bug! block_size is negative\n",
 571                                __FILE__, __func__);
 572                         break;
 573                 }
 574                 if ((int)(async->munge_ptr + block_size -
 575                           async->prealloc_bufsz) > 0)
 576                         block_size = async->prealloc_bufsz - async->munge_ptr;
 577
 578                 s->munge(s->device, s, async->prealloc_buf + async->munge_ptr,
 579                          block_size, async->munge_chan);
 580
 581                 smp_wmb();      /* barrier insures data is munged in buffer
 582                                  * before munge_count is incremented */
 583
 584                 async->munge_chan += block_size / num_sample_bytes;
 585                 async->munge_chan %= async->cmd.chanlist_len;
 586                 async->munge_count += block_size;
 587                 async->munge_ptr += block_size;
 588                 async->munge_ptr %= async->prealloc_bufsz;
 589                 count += block_size;
 590         }
 591         BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
 592         return count;
 593 }
 594
 595 unsigned int comedi_buf_write_n_available(struct comedi_async *async)
 596 {
 597         unsigned int free_end;
 598         unsigned int nbytes;
 599
 600         if (async == NULL)
 601                 return 0;
 602
 603         free_end = async->buf_read_count + async->prealloc_bufsz;
 604         nbytes = free_end - async->buf_write_alloc_count;
 605         nbytes -= nbytes % bytes_per_sample(async->subdevice);
 606         /* barrier insures the read of buf_read_count in this
 607            query occurs before any following writes to the buffer which
 608            might be based on the return value from this query.
 609          */
 610         smp_mb();
 611         return nbytes;
 612 }
 613
 614 /* allocates chunk for the writer from free buffer space */
 615 unsigned int comedi_buf_write_alloc(struct comedi_async *async,
 616                                     unsigned int nbytes)
 617 {
 618         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 619
 620         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0)
 621                 nbytes = free_end - async->buf_write_alloc_count;
 622
 623         async->buf_write_alloc_count += nbytes;
 624         /* barrier insures the read of buf_read_count above occurs before
 625            we write data to the write-alloc'ed buffer space */
 626         smp_mb();
 627         return nbytes;
 628 }
 629 EXPORT_SYMBOL(comedi_buf_write_alloc);
 630
 631 /* allocates nothing unless it can completely fulfill the request */
 632 unsigned int comedi_buf_write_alloc_strict(struct comedi_async *async,
 633                                            unsigned int nbytes)
 634 {
 635         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 636
 637         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0)
 638                 nbytes = 0;
 639
 640         async->buf_write_alloc_count += nbytes;
 641         /* barrier insures the read of buf_read_count above occurs before
 642            we write data to the write-alloc'ed buffer space */
 643         smp_mb();
 644         return nbytes;
 645 }
 646
 647 /* transfers a chunk from writer to filled buffer space */
 648 unsigned comedi_buf_write_free(struct comedi_async *async, unsigned int nbytes)
 649 {
 650         if ((int)(async->buf_write_count + nbytes -
 651                   async->buf_write_alloc_count) > 0) {
 652                 printk(KERN_INFO "comedi: attempted to write-free more bytes than have been write-allocated.\n");
 653                 nbytes = async->buf_write_alloc_count - async->buf_write_count;
 654         }
 655         async->buf_write_count += nbytes;
 656         async->buf_write_ptr += nbytes;
 657         comedi_buf_munge(async, async->buf_write_count - async->munge_count);
 658         if (async->buf_write_ptr >= async->prealloc_bufsz)
 659                 async->buf_write_ptr %= async->prealloc_bufsz;
 660
 661         return nbytes;
 662 }
 663 EXPORT_SYMBOL(comedi_buf_write_free);
 664
 665 /* allocates a chunk for the reader from filled (and munged) buffer space */
 666 unsigned comedi_buf_read_alloc(struct comedi_async *async, unsigned nbytes)
 667 {
 668         if ((int)(async->buf_read_alloc_count + nbytes - async->munge_count) >
 669             0) {
 670                 nbytes = async->munge_count - async->buf_read_alloc_count;
 671         }
 672         async->buf_read_alloc_count += nbytes;
 673         /* barrier insures read of munge_count occurs before we actually read
 674            data out of buffer */
 675         smp_rmb();
 676         return nbytes;
 677 }
 678 EXPORT_SYMBOL(comedi_buf_read_alloc);
 679
 680 /* transfers control of a chunk from reader to free buffer space */
 681 unsigned comedi_buf_read_free(struct comedi_async *async, unsigned int nbytes)
 682 {
 683         /* barrier insures data has been read out of
 684          * buffer before read count is incremented */
 685         smp_mb();
 686         if ((int)(async->buf_read_count + nbytes -
 687                   async->buf_read_alloc_count) > 0) {
 688                 printk(KERN_INFO
 689                        "comedi: attempted to read-free more bytes than have been read-allocated.\n");
 690                 nbytes = async->buf_read_alloc_count - async->buf_read_count;
 691         }
 692         async->buf_read_count += nbytes;
 693         async->buf_read_ptr += nbytes;
 694         async->buf_read_ptr %= async->prealloc_bufsz;
 695         return nbytes;
 696 }
 697 EXPORT_SYMBOL(comedi_buf_read_free);
 698
 699 void comedi_buf_memcpy_to(struct comedi_async *async, unsigned int offset,
 700                           const void *data, unsigned int num_bytes)
 701 {
 702         unsigned int write_ptr = async->buf_write_ptr + offset;
 703
 704         if (write_ptr >= async->prealloc_bufsz)
 705                 write_ptr %= async->prealloc_bufsz;
 706
 707         while (num_bytes) {
 708                 unsigned int block_size;
 709
 710                 if (write_ptr + num_bytes > async->prealloc_bufsz)
 711                         block_size = async->prealloc_bufsz - write_ptr;
 712                 else
 713                         block_size = num_bytes;
 714
 715                 memcpy(async->prealloc_buf + write_ptr, data, block_size);
 716
 717                 data += block_size;
 718                 num_bytes -= block_size;
 719
 720                 write_ptr = 0;
 721         }
 722 }
 723 EXPORT_SYMBOL(comedi_buf_memcpy_to);
 724
 725 void comedi_buf_memcpy_from(struct comedi_async *async, unsigned int offset,
 726                             void *dest, unsigned int nbytes)
 727 {
 728         void *src;
 729         unsigned int read_ptr = async->buf_read_ptr + offset;
 730
 731         if (read_ptr >= async->prealloc_bufsz)
 732                 read_ptr %= async->prealloc_bufsz;
 733
 734         while (nbytes) {
 735                 unsigned int block_size;
 736
 737                 src = async->prealloc_buf + read_ptr;
 738
 739                 if (nbytes >= async->prealloc_bufsz - read_ptr)
 740                         block_size = async->prealloc_bufsz - read_ptr;
 741                 else
 742                         block_size = nbytes;
 743
 744                 memcpy(dest, src, block_size);
 745                 nbytes -= block_size;
 746                 dest += block_size;
 747                 read_ptr = 0;
 748         }
 749 }
 750 EXPORT_SYMBOL(comedi_buf_memcpy_from);
 751
 752 unsigned int comedi_buf_read_n_available(struct comedi_async *async)
 753 {
 754         unsigned num_bytes;
 755
 756         if (async == NULL)
 757                 return 0;
 758         num_bytes = async->munge_count - async->buf_read_count;
 759         /* barrier insures the read of munge_count in this
 760            query occurs before any following reads of the buffer which
 761            might be based on the return value from this query.
 762          */
 763         smp_rmb();
 764         return num_bytes;
 765 }
 766 EXPORT_SYMBOL(comedi_buf_read_n_available);
 767
 768 int comedi_buf_get(struct comedi_async *async, short *x)
 769 {
 770         unsigned int n = comedi_buf_read_n_available(async);
 771
 772         if (n < sizeof(short))
 773                 return 0;
 774         comedi_buf_read_alloc(async, sizeof(short));
 775         *x = *(short *)(async->prealloc_buf + async->buf_read_ptr);
 776         comedi_buf_read_free(async, sizeof(short));
 777         return 1;
 778 }
 779 EXPORT_SYMBOL(comedi_buf_get);
 780
 781 int comedi_buf_put(struct comedi_async *async, short x)
 782 {
 783         unsigned int n = comedi_buf_write_alloc_strict(async, sizeof(short));
 784
 785         if (n < sizeof(short)) {
 786                 async->events |= COMEDI_CB_ERROR;
 787                 return 0;
 788         }
 789         *(short *)(async->prealloc_buf + async->buf_write_ptr) = x;
 790         comedi_buf_write_free(async, sizeof(short));
 791         return 1;
 792 }
 793 EXPORT_SYMBOL(comedi_buf_put);
 794
 795 void comedi_reset_async_buf(struct comedi_async *async)
 796 {
 797         async->buf_write_alloc_count = 0;
 798         async->buf_write_count = 0;
 799         async->buf_read_alloc_count = 0;
 800         async->buf_read_count = 0;
 801
 802         async->buf_write_ptr = 0;
 803         async->buf_read_ptr = 0;
 804
 805         async->cur_chan = 0;
 806         async->scan_progress = 0;
 807         async->munge_chan = 0;
 808         async->munge_count = 0;
 809         async->munge_ptr = 0;
 810
 811         async->events = 0;
 812 }
 813
 814 static int comedi_auto_config(struct device *hardware_device,
 815                               const char *board_name, const int *options,
 816                               unsigned num_options)
 817 {
 818         struct comedi_devconfig it;
 819         int minor;
 820         struct comedi_device_file_info *dev_file_info;
 821         int retval;
 822         unsigned *private_data = NULL;
 823
 824         if (!comedi_autoconfig) {
 825                 dev_set_drvdata(hardware_device, NULL);
 826                 return 0;
 827         }
 828
 829         minor = comedi_alloc_board_minor(hardware_device);
 830         if (minor < 0)
 831                 return minor;
 832
 833         private_data = kmalloc(sizeof(unsigned), GFP_KERNEL);
 834         if (private_data == NULL) {
 835                 retval = -ENOMEM;
 836                 goto cleanup;
 837         }
 838         *private_data = minor;
 839         dev_set_drvdata(hardware_device, private_data);
 840
 841         dev_file_info = comedi_get_device_file_info(minor);
 842
 843         memset(&it, 0, sizeof(it));
 844         strncpy(it.board_name, board_name, COMEDI_NAMELEN);
 845         it.board_name[COMEDI_NAMELEN - 1] = '\0';
 846         BUG_ON(num_options > COMEDI_NDEVCONFOPTS);
 847         memcpy(it.options, options, num_options * sizeof(int));
 848
 849         mutex_lock(&dev_file_info->device->mutex);
 850         retval = comedi_device_attach(dev_file_info->device, &it);
 851         mutex_unlock(&dev_file_info->device->mutex);
 852
 853 cleanup:
 854         if (retval < 0) {
 855                 kfree(private_data);
 856                 comedi_free_board_minor(minor);
 857         }
 858         return retval;
 859 }
 860
 861 static void comedi_auto_unconfig(struct device *hardware_device)
 862 {
 863         unsigned *minor = (unsigned *)dev_get_drvdata(hardware_device);
 864         if (minor == NULL)
 865                 return;
 866
 867         BUG_ON(*minor >= COMEDI_NUM_BOARD_MINORS);
 868
 869         comedi_free_board_minor(*minor);
 870         dev_set_drvdata(hardware_device, NULL);
 871         kfree(minor);
 872 }
 873
 874 int comedi_pci_auto_config(struct pci_dev *pcidev, const char *board_name)
 875 {
 876         int options[2];
 877
 878         /*  pci bus */
 879         options[0] = pcidev->bus->number;
 880         /*  pci slot */
 881         options[1] = PCI_SLOT(pcidev->devfn);
 882
 883         return comedi_auto_config(&pcidev->dev, board_name,
 884                                   options, ARRAY_SIZE(options));
 885 }
 886 EXPORT_SYMBOL_GPL(comedi_pci_auto_config);
 887
 888 void comedi_pci_auto_unconfig(struct pci_dev *pcidev)
 889 {
 890         comedi_auto_unconfig(&pcidev->dev);
 891 }
 892 EXPORT_SYMBOL_GPL(comedi_pci_auto_unconfig);
 893
 894 int comedi_usb_auto_config(struct usb_device *usbdev, const char *board_name)
 895 {
 896         BUG_ON(usbdev == NULL);
 897         return comedi_auto_config(&usbdev->dev, board_name, NULL, 0);
 898 }
 899 EXPORT_SYMBOL_GPL(comedi_usb_auto_config);
 900
 901 void comedi_usb_auto_unconfig(struct usb_device *usbdev)
 902 {
 903         BUG_ON(usbdev == NULL);
 904         comedi_auto_unconfig(&usbdev->dev);
 905 }
 906 EXPORT_SYMBOL_GPL(comedi_usb_auto_unconfig);