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
 121                             (KERN_INFO "comedi: failed to increment module count, skipping\n");
 122                         continue;
 123                 }
 124                 if (driv->num_names) {
 125                         dev->board_ptr = comedi_recognize(driv, it->board_name);
 126                         if (dev->board_ptr == NULL) {
 127                                 module_put(driv->module);
 128                                 continue;
 129                         }
 130                 } else {
 131                         if (strcmp(driv->driver_name, it->board_name)) {
 132                                 module_put(driv->module);
 133                                 continue;
 134                         }
 135                 }
 136                 /* initialize dev->driver here so
 137                  * comedi_error() can be called from attach */
 138                 dev->driver = driv;
 139                 ret = driv->attach(dev, it);
 140                 if (ret < 0) {
 141                         module_put(dev->driver->module);
 142                         __comedi_device_detach(dev);
 143                         return ret;
 144                 }
 145                 goto attached;
 146         }
 147
 148         /*  recognize has failed if we get here */
 149         /*  report valid board names before returning error */
 150         for (driv = comedi_drivers; driv; driv = driv->next) {
 151                 if (!try_module_get(driv->module)) {
 152                         printk(KERN_INFO
 153                                "comedi: failed to increment module count\n");
 154                         continue;
 155                 }
 156                 comedi_report_boards(driv);
 157                 module_put(driv->module);
 158         }
 159         return -EIO;
 160
 161 attached:
 162         /* do a little post-config cleanup */
 163         ret = postconfig(dev);
 164         module_put(dev->driver->module);
 165         if (ret < 0) {
 166                 __comedi_device_detach(dev);
 167                 return ret;
 168         }
 169
 170         if (!dev->board_name) {
 171                 printk(KERN_WARNING "BUG: dev->board_name=<%p>\n",
 172                        dev->board_name);
 173                 dev->board_name = "BUG";
 174         }
 175         smp_wmb();
 176         dev->attached = 1;
 177
 178         return 0;
 179 }
 180
 181 int comedi_driver_register(struct comedi_driver *driver)
 182 {
 183         driver->next = comedi_drivers;
 184         comedi_drivers = driver;
 185
 186         return 0;
 187 }
 188 EXPORT_SYMBOL(comedi_driver_register);
 189
 190 int comedi_driver_unregister(struct comedi_driver *driver)
 191 {
 192         struct comedi_driver *prev;
 193         int i;
 194
 195         /* check for devices using this driver */
 196         for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
 197                 struct comedi_device_file_info *dev_file_info =
 198                     comedi_get_device_file_info(i);
 199                 struct comedi_device *dev;
 200
 201                 if (dev_file_info == NULL)
 202                         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
 209                                     (KERN_WARNING "BUG! detaching device with use_count=%d\n",
 210                                      dev->use_count);
 211                         comedi_device_detach(dev);
 212                 }
 213                 mutex_unlock(&dev->mutex);
 214         }
 215
 216         if (comedi_drivers == driver) {
 217                 comedi_drivers = driver->next;
 218                 return 0;
 219         }
 220
 221         for (prev = comedi_drivers; prev->next; prev = prev->next) {
 222                 if (prev->next == driver) {
 223                         prev->next = driver->next;
 224                         return 0;
 225                 }
 226         }
 227         return -EINVAL;
 228 }
 229 EXPORT_SYMBOL(comedi_driver_unregister);
 230
 231 static int postconfig(struct comedi_device *dev)
 232 {
 233         int i;
 234         struct comedi_subdevice *s;
 235         struct comedi_async *async = NULL;
 236         int ret;
 237
 238         for (i = 0; i < dev->n_subdevices; i++) {
 239                 s = dev->subdevices + i;
 240
 241                 if (s->type == COMEDI_SUBD_UNUSED)
 242                         continue;
 243
 244                 if (s->len_chanlist == 0)
 245                         s->len_chanlist = 1;
 246
 247                 if (s->do_cmd) {
 248                         BUG_ON((s->subdev_flags & (SDF_CMD_READ |
 249                                                    SDF_CMD_WRITE)) == 0);
 250                         BUG_ON(!s->do_cmdtest);
 251
 252                         async =
 253                             kzalloc(sizeof(struct comedi_async), GFP_KERNEL);
 254                         if (async == NULL) {
 255                                 printk(KERN_INFO
 256                                        "failed to allocate async struct\n");
 257                                 return -ENOMEM;
 258                         }
 259                         init_waitqueue_head(&async->wait_head);
 260                         async->subdevice = s;
 261                         s->async = async;
 262
 263 #define DEFAULT_BUF_MAXSIZE (64*1024)
 264 #define DEFAULT_BUF_SIZE (64*1024)
 265
 266                         async->max_bufsize = DEFAULT_BUF_MAXSIZE;
 267
 268                         async->prealloc_buf = NULL;
 269                         async->prealloc_bufsz = 0;
 270                         if (comedi_buf_alloc(dev, s, DEFAULT_BUF_SIZE) < 0) {
 271                                 printk(KERN_INFO "Buffer allocation failed\n");
 272                                 return -ENOMEM;
 273                         }
 274                         if (s->buf_change) {
 275                                 ret = s->buf_change(dev, s, DEFAULT_BUF_SIZE);
 276                                 if (ret < 0)
 277                                         return ret;
 278                         }
 279                         comedi_alloc_subdevice_minor(dev, s);
 280                 }
 281
 282                 if (!s->range_table && !s->range_table_list)
 283                         s->range_table = &range_unknown;
 284
 285                 if (!s->insn_read && s->insn_bits)
 286                         s->insn_read = insn_rw_emulate_bits;
 287                 if (!s->insn_write && s->insn_bits)
 288                         s->insn_write = insn_rw_emulate_bits;
 289
 290                 if (!s->insn_read)
 291                         s->insn_read = insn_inval;
 292                 if (!s->insn_write)
 293                         s->insn_write = insn_inval;
 294                 if (!s->insn_bits)
 295                         s->insn_bits = insn_inval;
 296                 if (!s->insn_config)
 297                         s->insn_config = insn_inval;
 298
 299                 if (!s->poll)
 300                         s->poll = poll_invalid;
 301         }
 302
 303         return 0;
 304 }
 305
 306 /* generic recognize function for drivers
 307  * that register their supported board names */
 308 static 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 static void comedi_report_boards(struct comedi_driver *driv)
 324 {
 325         unsigned int i;
 326         const char *const *name_ptr;
 327
 328         printk(KERN_INFO "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(KERN_INFO " %s\n", *name_ptr);
 334                 name_ptr = (const char **)((char *)name_ptr + driv->offset);
 335         }
 336
 337         if (driv->num_names == 0)
 338                 printk(KERN_INFO " %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))
 377                               : 0; /* bits */
 378         }
 379
 380         ret = s->insn_bits(dev, s, &new_insn, new_data);
 381         if (ret < 0)
 382                 return ret;
 383
 384         if (insn->insn == INSN_READ)
 385                 data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1;
 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                                 clear_bit(PG_reserved, &(virt_to_page(async->buf_page_list[i].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                     vmalloc(sizeof(struct comedi_buf_page) * n_pages);
 474                 if (async->buf_page_list) {
 475                         memset(async->buf_page_list, 0,
 476                                sizeof(struct comedi_buf_page) * n_pages);
 477                         pages = vmalloc(sizeof(struct page *) * n_pages);
 478                 }
 479                 if (pages) {
 480                         for (i = 0; i < n_pages; i++) {
 481                                 if (s->async_dma_dir != DMA_NONE) {
 482                                         async->buf_page_list[i].virt_addr =
 483                                             dma_alloc_coherent(dev->hw_dev,
 484                                                                PAGE_SIZE,
 485                                                                &async->
 486                                                                buf_page_list
 487                                                                [i].dma_addr,
 488                                                                GFP_KERNEL |
 489                                                                __GFP_COMP);
 490                                 } else {
 491                                         async->buf_page_list[i].virt_addr =
 492                                             (void *)
 493                                             get_zeroed_page(GFP_KERNEL);
 494                                 }
 495                                 if (async->buf_page_list[i].virt_addr == NULL)
 496                                         break;
 497
 498                                 set_bit(PG_reserved,
 499                                         &(virt_to_page(async->buf_page_list[i].virt_addr)->flags));
 500                                 pages[i] = virt_to_page(async->buf_page_list[i].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, &(virt_to_page(async->buf_page_list[i].virt_addr)->flags));
 518                                         if (s->async_dma_dir != DMA_NONE) {
 519                                                 dma_free_coherent(dev->hw_dev,
 520                                                                   PAGE_SIZE,
 521                                                                   async->
 522                                                                   buf_page_list
 523                                                                   [i].virt_addr,
 524                                                                   async->
 525                                                                   buf_page_list
 526                                                                   [i].dma_addr);
 527                                         } else {
 528                                                 free_page((unsigned long)
 529                                                           async->buf_page_list
 530                                                           [i].virt_addr);
 531                                         }
 532                                 }
 533                                 vfree(async->buf_page_list);
 534                                 async->buf_page_list = NULL;
 535                         }
 536                         return -ENOMEM;
 537                 }
 538                 async->n_buf_pages = n_pages;
 539         }
 540         async->prealloc_bufsz = new_size;
 541
 542         return 0;
 543 }
 544
 545 /* munging is applied to data by core as it passes between user
 546  * and kernel space */
 547 static unsigned int comedi_buf_munge(struct comedi_async *async,
 548                                      unsigned int num_bytes)
 549 {
 550         struct comedi_subdevice *s = async->subdevice;
 551         unsigned int count = 0;
 552         const unsigned num_sample_bytes = bytes_per_sample(s);
 553
 554         if (s->munge == NULL || (async->cmd.flags & CMDF_RAWDATA)) {
 555                 async->munge_count += num_bytes;
 556                 BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
 557                 return num_bytes;
 558         }
 559         /* don't munge partial samples */
 560         num_bytes -= num_bytes % num_sample_bytes;
 561         while (count < num_bytes) {
 562                 int block_size;
 563
 564                 block_size = num_bytes - count;
 565                 if (block_size < 0) {
 566                         printk(KERN_WARNING
 567                                "%s: %s: bug! block_size is negative\n",
 568                                __FILE__, __func__);
 569                         break;
 570                 }
 571                 if ((int)(async->munge_ptr + block_size -
 572                           async->prealloc_bufsz) > 0)
 573                         block_size = async->prealloc_bufsz - async->munge_ptr;
 574
 575                 s->munge(s->device, s, async->prealloc_buf + async->munge_ptr,
 576                          block_size, async->munge_chan);
 577
 578                 smp_wmb();      /* barrier insures data is munged in buffer
 579                                  * before munge_count is incremented */
 580
 581                 async->munge_chan += block_size / num_sample_bytes;
 582                 async->munge_chan %= async->cmd.chanlist_len;
 583                 async->munge_count += block_size;
 584                 async->munge_ptr += block_size;
 585                 async->munge_ptr %= async->prealloc_bufsz;
 586                 count += block_size;
 587         }
 588         BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
 589         return count;
 590 }
 591
 592 unsigned int comedi_buf_write_n_available(struct comedi_async *async)
 593 {
 594         unsigned int free_end;
 595         unsigned int nbytes;
 596
 597         if (async == NULL)
 598                 return 0;
 599
 600         free_end = async->buf_read_count + async->prealloc_bufsz;
 601         nbytes = free_end - async->buf_write_alloc_count;
 602         nbytes -= nbytes % bytes_per_sample(async->subdevice);
 603         /* barrier insures the read of buf_read_count in this
 604            query occurs before any following writes to the buffer which
 605            might be based on the return value from this query.
 606          */
 607         smp_mb();
 608         return nbytes;
 609 }
 610
 611 /* allocates chunk for the writer from free buffer space */
 612 unsigned int comedi_buf_write_alloc(struct comedi_async *async,
 613                                     unsigned int nbytes)
 614 {
 615         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 616
 617         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0)
 618                 nbytes = free_end - async->buf_write_alloc_count;
 619
 620         async->buf_write_alloc_count += nbytes;
 621         /* barrier insures the read of buf_read_count above occurs before
 622            we write data to the write-alloc'ed buffer space */
 623         smp_mb();
 624         return nbytes;
 625 }
 626 EXPORT_SYMBOL(comedi_buf_write_alloc);
 627
 628 /* allocates nothing unless it can completely fulfill the request */
 629 unsigned int comedi_buf_write_alloc_strict(struct comedi_async *async,
 630                                            unsigned int nbytes)
 631 {
 632         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 633
 634         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0)
 635                 nbytes = 0;
 636
 637         async->buf_write_alloc_count += nbytes;
 638         /* barrier insures the read of buf_read_count above occurs before
 639            we write data to the write-alloc'ed buffer space */
 640         smp_mb();
 641         return nbytes;
 642 }
 643
 644 /* transfers a chunk from writer to filled buffer space */
 645 unsigned comedi_buf_write_free(struct comedi_async *async, unsigned int nbytes)
 646 {
 647         if ((int)(async->buf_write_count + nbytes -
 648                   async->buf_write_alloc_count) > 0) {
 649                 printk
 650                     (KERN_INFO "comedi: attempted to write-free more bytes than have been write-allocated.\n");
 651                 nbytes = async->buf_write_alloc_count - async->buf_write_count;
 652         }
 653         async->buf_write_count += nbytes;
 654         async->buf_write_ptr += nbytes;
 655         comedi_buf_munge(async, async->buf_write_count - async->munge_count);
 656         if (async->buf_write_ptr >= async->prealloc_bufsz)
 657                 async->buf_write_ptr %= async->prealloc_bufsz;
 658
 659         return nbytes;
 660 }
 661 EXPORT_SYMBOL(comedi_buf_write_free);
 662
 663 /* allocates a chunk for the reader from filled (and munged) buffer space */
 664 unsigned comedi_buf_read_alloc(struct comedi_async *async, unsigned nbytes)
 665 {
 666         if ((int)(async->buf_read_alloc_count + nbytes - async->munge_count) >
 667             0) {
 668                 nbytes = async->munge_count - async->buf_read_alloc_count;
 669         }
 670         async->buf_read_alloc_count += nbytes;
 671         /* barrier insures read of munge_count occurs before we actually read
 672            data out of buffer */
 673         smp_rmb();
 674         return nbytes;
 675 }
 676 EXPORT_SYMBOL(comedi_buf_read_alloc);
 677
 678 /* transfers control of a chunk from reader to free buffer space */
 679 unsigned comedi_buf_read_free(struct comedi_async *async, unsigned int nbytes)
 680 {
 681         /* barrier insures data has been read out of
 682          * buffer before read count is incremented */
 683         smp_mb();
 684         if ((int)(async->buf_read_count + nbytes -
 685                   async->buf_read_alloc_count) > 0) {
 686                 printk(KERN_INFO
 687                        "comedi: attempted to read-free more bytes than have been read-allocated.\n");
 688                 nbytes = async->buf_read_alloc_count - async->buf_read_count;
 689         }
 690         async->buf_read_count += nbytes;
 691         async->buf_read_ptr += nbytes;
 692         async->buf_read_ptr %= async->prealloc_bufsz;
 693         return nbytes;
 694 }
 695 EXPORT_SYMBOL(comedi_buf_read_free);
 696
 697 void comedi_buf_memcpy_to(struct comedi_async *async, unsigned int offset,
 698                           const void *data, unsigned int num_bytes)
 699 {
 700         unsigned int write_ptr = async->buf_write_ptr + offset;
 701
 702         if (write_ptr >= async->prealloc_bufsz)
 703                 write_ptr %= async->prealloc_bufsz;
 704
 705         while (num_bytes) {
 706                 unsigned int block_size;
 707
 708                 if (write_ptr + num_bytes > async->prealloc_bufsz)
 709                         block_size = async->prealloc_bufsz - write_ptr;
 710                 else
 711                         block_size = num_bytes;
 712
 713                 memcpy(async->prealloc_buf + write_ptr, data, block_size);
 714
 715                 data += block_size;
 716                 num_bytes -= block_size;
 717
 718                 write_ptr = 0;
 719         }
 720 }
 721 EXPORT_SYMBOL(comedi_buf_memcpy_to);
 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 EXPORT_SYMBOL(comedi_buf_memcpy_from);
 749
 750 unsigned int comedi_buf_read_n_available(struct comedi_async *async)
 751 {
 752         unsigned num_bytes;
 753
 754         if (async == NULL)
 755                 return 0;
 756         num_bytes = async->munge_count - async->buf_read_count;
 757         /* barrier insures the read of munge_count in this
 758            query occurs before any following reads of the buffer which
 759            might be based on the return value from this query.
 760          */
 761         smp_rmb();
 762         return num_bytes;
 763 }
 764 EXPORT_SYMBOL(comedi_buf_read_n_available);
 765
 766 int comedi_buf_get(struct comedi_async *async, short *x)
 767 {
 768         unsigned int n = comedi_buf_read_n_available(async);
 769
 770         if (n < sizeof(short))
 771                 return 0;
 772         comedi_buf_read_alloc(async, sizeof(short));
 773         *x = *(short *)(async->prealloc_buf + async->buf_read_ptr);
 774         comedi_buf_read_free(async, sizeof(short));
 775         return 1;
 776 }
 777 EXPORT_SYMBOL(comedi_buf_get);
 778
 779 int comedi_buf_put(struct comedi_async *async, short x)
 780 {
 781         unsigned int n = comedi_buf_write_alloc_strict(async, sizeof(short));
 782
 783         if (n < sizeof(short)) {
 784                 async->events |= COMEDI_CB_ERROR;
 785                 return 0;
 786         }
 787         *(short *)(async->prealloc_buf + async->buf_write_ptr) = x;
 788         comedi_buf_write_free(async, sizeof(short));
 789         return 1;
 790 }
 791 EXPORT_SYMBOL(comedi_buf_put);
 792
 793 void comedi_reset_async_buf(struct comedi_async *async)
 794 {
 795         async->buf_write_alloc_count = 0;
 796         async->buf_write_count = 0;
 797         async->buf_read_alloc_count = 0;
 798         async->buf_read_count = 0;
 799
 800         async->buf_write_ptr = 0;
 801         async->buf_read_ptr = 0;
 802
 803         async->cur_chan = 0;
 804         async->scan_progress = 0;
 805         async->munge_chan = 0;
 806         async->munge_count = 0;
 807         async->munge_ptr = 0;
 808
 809         async->events = 0;
 810 }
 811
 812 static int comedi_auto_config(struct device *hardware_device,
 813                               const char *board_name, const int *options,
 814                               unsigned num_options)
 815 {
 816         struct comedi_devconfig it;
 817         int minor;
 818         struct comedi_device_file_info *dev_file_info;
 819         int retval;
 820         unsigned *private_data = NULL;
 821
 822         if (!comedi_autoconfig) {
 823                 dev_set_drvdata(hardware_device, NULL);
 824                 return 0;
 825         }
 826
 827         minor = comedi_alloc_board_minor(hardware_device);
 828         if (minor < 0)
 829                 return minor;
 830
 831         private_data = kmalloc(sizeof(unsigned), GFP_KERNEL);
 832         if (private_data == NULL) {
 833                 retval = -ENOMEM;
 834                 goto cleanup;
 835         }
 836         *private_data = minor;
 837         dev_set_drvdata(hardware_device, private_data);
 838
 839         dev_file_info = comedi_get_device_file_info(minor);
 840
 841         memset(&it, 0, sizeof(it));
 842         strncpy(it.board_name, board_name, COMEDI_NAMELEN);
 843         it.board_name[COMEDI_NAMELEN - 1] = '\0';
 844         BUG_ON(num_options > COMEDI_NDEVCONFOPTS);
 845         memcpy(it.options, options, num_options * sizeof(int));
 846
 847         mutex_lock(&dev_file_info->device->mutex);
 848         retval = comedi_device_attach(dev_file_info->device, &it);
 849         mutex_unlock(&dev_file_info->device->mutex);
 850
 851 cleanup:
 852         if (retval < 0) {
 853                 kfree(private_data);
 854                 comedi_free_board_minor(minor);
 855         }
 856         return retval;
 857 }
 858
 859 static void comedi_auto_unconfig(struct device *hardware_device)
 860 {
 861         unsigned *minor = (unsigned *)dev_get_drvdata(hardware_device);
 862         if (minor == NULL)
 863                 return;
 864
 865         BUG_ON(*minor >= COMEDI_NUM_BOARD_MINORS);
 866
 867         comedi_free_board_minor(*minor);
 868         dev_set_drvdata(hardware_device, NULL);
 869         kfree(minor);
 870 }
 871
 872 int comedi_pci_auto_config(struct pci_dev *pcidev, const char *board_name)
 873 {
 874         int options[2];
 875
 876         /*  pci bus */
 877         options[0] = pcidev->bus->number;
 878         /*  pci slot */
 879         options[1] = PCI_SLOT(pcidev->devfn);
 880
 881         return comedi_auto_config(&pcidev->dev, board_name,
 882                                   options, ARRAY_SIZE(options));
 883 }
 884 EXPORT_SYMBOL_GPL(comedi_pci_auto_config);
 885
 886 void comedi_pci_auto_unconfig(struct pci_dev *pcidev)
 887 {
 888         comedi_auto_unconfig(&pcidev->dev);
 889 }
 890 EXPORT_SYMBOL_GPL(comedi_pci_auto_unconfig);
 891
 892 int comedi_usb_auto_config(struct usb_device *usbdev, const char *board_name)
 893 {
 894         BUG_ON(usbdev == NULL);
 895         return comedi_auto_config(&usbdev->dev, board_name, NULL, 0);
 896 }
 897 EXPORT_SYMBOL_GPL(comedi_usb_auto_config);
 898
 899 void comedi_usb_auto_unconfig(struct usb_device *usbdev)
 900 {
 901         BUG_ON(usbdev == NULL);
 902         comedi_auto_unconfig(&usbdev->dev);
 903 }
 904 EXPORT_SYMBOL_GPL(comedi_usb_auto_unconfig);