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