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