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 <linux/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         cleanup_device(dev);
 107 }
 108
 109 void comedi_device_detach(struct comedi_device *dev)
 110 {
 111         if (!dev->attached)
 112                 return;
 113         __comedi_device_detach(dev);
 114 }
 115
 116 int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 117 {
 118         struct comedi_driver *driv;
 119         int ret;
 120
 121         if (dev->attached)
 122                 return -EBUSY;
 123
 124         for (driv = comedi_drivers; driv; driv = driv->next) {
 125                 if (!try_module_get(driv->module)) {
 126                         printk
 127                             ("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(struct comedi_driver *driver)
 185 {
 186         driver->next = comedi_drivers;
 187         comedi_drivers = driver;
 188
 189         return 0;
 190 }
 191
 192 int comedi_driver_unregister(struct comedi_driver *driver)
 193 {
 194         struct 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 =
 200                     comedi_get_device_file_info(i);
 201                 struct comedi_device *dev;
 202
 203                 if (dev_file_info == NULL)
 204                         continue;
 205                 dev = dev_file_info->device;
 206
 207                 mutex_lock(&dev->mutex);
 208                 if (dev->attached && dev->driver == driver) {
 209                         if (dev->use_count)
 210                                 printk
 211                                     ("BUG! detaching device with use_count=%d\n",
 212                                      dev->use_count);
 213                         comedi_device_detach(dev);
 214                 }
 215                 mutex_unlock(&dev->mutex);
 216         }
 217
 218         if (comedi_drivers == driver) {
 219                 comedi_drivers = driver->next;
 220                 return 0;
 221         }
 222
 223         for (prev = comedi_drivers; prev->next; prev = prev->next) {
 224                 if (prev->next == driver) {
 225                         prev->next = driver->next;
 226                         return 0;
 227                 }
 228         }
 229         return -EINVAL;
 230 }
 231
 232 static int postconfig(struct comedi_device *dev)
 233 {
 234         int i;
 235         struct comedi_subdevice *s;
 236         struct comedi_async *async = NULL;
 237         int ret;
 238
 239         for (i = 0; i < dev->n_subdevices; i++) {
 240                 s = dev->subdevices + i;
 241
 242                 if (s->type == COMEDI_SUBD_UNUSED)
 243                         continue;
 244
 245                 if (s->len_chanlist == 0)
 246                         s->len_chanlist = 1;
 247
 248                 if (s->do_cmd) {
 249                         BUG_ON((s->subdev_flags & (SDF_CMD_READ |
 250                                                    SDF_CMD_WRITE)) == 0);
 251                         BUG_ON(!s->do_cmdtest);
 252
 253                         async =
 254                             kzalloc(sizeof(struct comedi_async), GFP_KERNEL);
 255                         if (async == NULL) {
 256                                 printk("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("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 that register their supported board names */
 307 void *comedi_recognize(struct comedi_driver *driv, const char *name)
 308 {
 309         unsigned i;
 310         const char *const *name_ptr = driv->board_name;
 311         for (i = 0; i < driv->num_names; i++) {
 312                 if (strcmp(*name_ptr, name) == 0)
 313                         return (void *)name_ptr;
 314                 name_ptr =
 315                     (const char *const *)((const char *)name_ptr +
 316                                           driv->offset);
 317         }
 318
 319         return NULL;
 320 }
 321
 322 void comedi_report_boards(struct comedi_driver *driv)
 323 {
 324         unsigned int i;
 325         const char *const *name_ptr;
 326
 327         printk("comedi: valid board names for %s driver are:\n",
 328                driv->driver_name);
 329
 330         name_ptr = driv->board_name;
 331         for (i = 0; i < driv->num_names; i++) {
 332                 printk(" %s\n", *name_ptr);
 333                 name_ptr = (const char **)((char *)name_ptr + driv->offset);
 334         }
 335
 336         if (driv->num_names == 0)
 337                 printk(" %s\n", driv->driver_name);
 338 }
 339
 340 static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s)
 341 {
 342         return -EINVAL;
 343 }
 344
 345 int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s,
 346                struct comedi_insn *insn, unsigned int *data)
 347 {
 348         return -EINVAL;
 349 }
 350
 351 static int insn_rw_emulate_bits(struct comedi_device *dev,
 352                                 struct comedi_subdevice *s,
 353                                 struct comedi_insn *insn, unsigned int *data)
 354 {
 355         struct comedi_insn new_insn;
 356         int ret;
 357         static const unsigned channels_per_bitfield = 32;
 358
 359         unsigned chan = CR_CHAN(insn->chanspec);
 360         const unsigned base_bitfield_channel =
 361             (chan < channels_per_bitfield) ? 0 : chan;
 362         unsigned int new_data[2];
 363         memset(new_data, 0, sizeof(new_data));
 364         memset(&new_insn, 0, sizeof(new_insn));
 365         new_insn.insn = INSN_BITS;
 366         new_insn.chanspec = base_bitfield_channel;
 367         new_insn.n = 2;
 368         new_insn.data = new_data;
 369         new_insn.subdev = insn->subdev;
 370
 371         if (insn->insn == INSN_WRITE) {
 372                 if (!(s->subdev_flags & SDF_WRITABLE))
 373                         return -EINVAL;
 374                 new_data[0] = 1 << (chan - base_bitfield_channel);      /* mask */
 375                 new_data[1] = data[0] ? (1 << (chan - base_bitfield_channel)) : 0;      /* bits */
 376         }
 377
 378         ret = s->insn_bits(dev, s, &new_insn, new_data);
 379         if (ret < 0)
 380                 return ret;
 381
 382         if (insn->insn == INSN_READ)
 383                 data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1;
 384
 385         return 1;
 386 }
 387
 388 static inline unsigned long uvirt_to_kva(pgd_t *pgd, unsigned long adr)
 389 {
 390         unsigned long ret = 0UL;
 391         pmd_t *pmd;
 392         pte_t *ptep, pte;
 393         pud_t *pud;
 394
 395         if (!pgd_none(*pgd)) {
 396                 pud = pud_offset(pgd, adr);
 397                 pmd = pmd_offset(pud, adr);
 398                 if (!pmd_none(*pmd)) {
 399                         ptep = pte_offset_kernel(pmd, adr);
 400                         pte = *ptep;
 401                         if (pte_present(pte)) {
 402                                 ret = (unsigned long)
 403                                     page_address(pte_page(pte));
 404                                 ret |= (adr & (PAGE_SIZE - 1));
 405                         }
 406                 }
 407         }
 408         return ret;
 409 }
 410
 411 static inline unsigned long kvirt_to_kva(unsigned long adr)
 412 {
 413         unsigned long va, kva;
 414
 415         va = adr;
 416         kva = uvirt_to_kva(pgd_offset_k(va), va);
 417
 418         return kva;
 419 }
 420
 421 int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
 422                      unsigned long new_size)
 423 {
 424         struct comedi_async *async = s->async;
 425
 426         /* Round up new_size to multiple of PAGE_SIZE */
 427         new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
 428
 429         /* if no change is required, do nothing */
 430         if (async->prealloc_buf && async->prealloc_bufsz == new_size)
 431                 return 0;
 432
 433         /*  deallocate old buffer */
 434         if (async->prealloc_buf) {
 435                 vunmap(async->prealloc_buf);
 436                 async->prealloc_buf = NULL;
 437                 async->prealloc_bufsz = 0;
 438         }
 439         if (async->buf_page_list) {
 440                 unsigned i;
 441                 for (i = 0; i < async->n_buf_pages; ++i) {
 442                         if (async->buf_page_list[i].virt_addr) {
 443                                 mem_map_unreserve(virt_to_page
 444                                                   (async->buf_page_list[i].
 445                                                    virt_addr));
 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                                 mem_map_reserve(virt_to_page
 499                                                 (async->buf_page_list[i].
 500                                                  virt_addr));
 501                                 pages[i] =
 502                                     virt_to_page(async->
 503                                                  buf_page_list[i].virt_addr);
 504                         }
 505                 }
 506                 if (i == n_pages) {
 507                         async->prealloc_buf =
 508                             vmap(pages, n_pages, VM_MAP, PAGE_KERNEL_NOCACHE);
 509                 }
 510                 vfree(pages);
 511
 512                 if (async->prealloc_buf == NULL) {
 513                         /* Some allocation failed above. */
 514                         if (async->buf_page_list) {
 515                                 for (i = 0; i < n_pages; i++) {
 516                                         if (async->buf_page_list[i].virt_addr ==
 517                                             NULL) {
 518                                                 break;
 519                                         }
 520                                         mem_map_unreserve(virt_to_page
 521                                                           (async->buf_page_list
 522                                                            [i].virt_addr));
 523                                         if (s->async_dma_dir != DMA_NONE) {
 524                                                 dma_free_coherent(dev->hw_dev,
 525                                                                   PAGE_SIZE,
 526                                                                   async->
 527                                                                   buf_page_list
 528                                                                   [i].virt_addr,
 529                                                                   async->
 530                                                                   buf_page_list
 531                                                                   [i].dma_addr);
 532                                         } else {
 533                                                 free_page((unsigned long)
 534                                                           async->buf_page_list
 535                                                           [i].virt_addr);
 536                                         }
 537                                 }
 538                                 vfree(async->buf_page_list);
 539                                 async->buf_page_list = NULL;
 540                         }
 541                         return -ENOMEM;
 542                 }
 543                 async->n_buf_pages = n_pages;
 544         }
 545         async->prealloc_bufsz = new_size;
 546
 547         return 0;
 548 }
 549
 550 /* munging is applied to data by core as it passes between user
 551  * and kernel space */
 552 unsigned int comedi_buf_munge(struct comedi_async *async,
 553                               unsigned int num_bytes)
 554 {
 555         struct comedi_subdevice *s = async->subdevice;
 556         unsigned int count = 0;
 557         const unsigned num_sample_bytes = bytes_per_sample(s);
 558
 559         if (s->munge == NULL || (async->cmd.flags & CMDF_RAWDATA)) {
 560                 async->munge_count += num_bytes;
 561                 BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
 562                 return num_bytes;
 563         }
 564         /* don't munge partial samples */
 565         num_bytes -= num_bytes % num_sample_bytes;
 566         while (count < num_bytes) {
 567                 int block_size;
 568
 569                 block_size = num_bytes - count;
 570                 if (block_size < 0) {
 571                         printk("%s: %s: bug! block_size is negative\n",
 572                                __FILE__, __func__);
 573                         break;
 574                 }
 575                 if ((int)(async->munge_ptr + block_size -
 576                           async->prealloc_bufsz) > 0)
 577                         block_size = async->prealloc_bufsz - async->munge_ptr;
 578
 579                 s->munge(s->device, s, async->prealloc_buf + async->munge_ptr,
 580                          block_size, async->munge_chan);
 581
 582                 smp_wmb();      /* barrier insures data is munged in buffer before munge_count is incremented */
 583
 584                 async->munge_chan += block_size / num_sample_bytes;
 585                 async->munge_chan %= async->cmd.chanlist_len;
 586                 async->munge_count += block_size;
 587                 async->munge_ptr += block_size;
 588                 async->munge_ptr %= async->prealloc_bufsz;
 589                 count += block_size;
 590         }
 591         BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
 592         return count;
 593 }
 594
 595 unsigned int comedi_buf_write_n_available(struct comedi_async *async)
 596 {
 597         unsigned int free_end;
 598         unsigned int nbytes;
 599
 600         if (async == NULL)
 601                 return 0;
 602
 603         free_end = async->buf_read_count + async->prealloc_bufsz;
 604         nbytes = free_end - async->buf_write_alloc_count;
 605         nbytes -= nbytes % bytes_per_sample(async->subdevice);
 606         /* barrier insures the read of buf_read_count in this
 607            query occurs before any following writes to the buffer which
 608            might be based on the return value from this query.
 609          */
 610         smp_mb();
 611         return nbytes;
 612 }
 613
 614 /* allocates chunk for the writer from free buffer space */
 615 unsigned int comedi_buf_write_alloc(struct comedi_async *async,
 616                                     unsigned int nbytes)
 617 {
 618         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 619
 620         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0)
 621                 nbytes = free_end - async->buf_write_alloc_count;
 622
 623         async->buf_write_alloc_count += nbytes;
 624         /* barrier insures the read of buf_read_count above occurs before
 625            we write data to the write-alloc'ed buffer space */
 626         smp_mb();
 627         return nbytes;
 628 }
 629
 630 /* allocates nothing unless it can completely fulfill the request */
 631 unsigned int comedi_buf_write_alloc_strict(struct comedi_async *async,
 632                                            unsigned int nbytes)
 633 {
 634         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 635
 636         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0)
 637                 nbytes = 0;
 638
 639         async->buf_write_alloc_count += nbytes;
 640         /* barrier insures the read of buf_read_count above occurs before
 641            we write data to the write-alloc'ed buffer space */
 642         smp_mb();
 643         return nbytes;
 644 }
 645
 646 /* transfers a chunk from writer to filled buffer space */
 647 unsigned comedi_buf_write_free(struct comedi_async *async, unsigned int nbytes)
 648 {
 649         if ((int)(async->buf_write_count + nbytes -
 650                   async->buf_write_alloc_count) > 0) {
 651                 printk
 652                     ("comedi: attempted to write-free more bytes than have been write-allocated.\n");
 653                 nbytes = async->buf_write_alloc_count - async->buf_write_count;
 654         }
 655         async->buf_write_count += nbytes;
 656         async->buf_write_ptr += nbytes;
 657         comedi_buf_munge(async, async->buf_write_count - async->munge_count);
 658         if (async->buf_write_ptr >= async->prealloc_bufsz)
 659                 async->buf_write_ptr %= async->prealloc_bufsz;
 660
 661         return nbytes;
 662 }
 663
 664 /* allocates a chunk for the reader from filled (and munged) buffer space */
 665 unsigned comedi_buf_read_alloc(struct comedi_async *async, unsigned nbytes)
 666 {
 667         if ((int)(async->buf_read_alloc_count + nbytes - async->munge_count) >
 668             0) {
 669                 nbytes = async->munge_count - async->buf_read_alloc_count;
 670         }
 671         async->buf_read_alloc_count += nbytes;
 672         /* barrier insures read of munge_count occurs before we actually read
 673            data out of buffer */
 674         smp_rmb();
 675         return nbytes;
 676 }
 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 buffer before read count is incremented */
 682         smp_mb();
 683         if ((int)(async->buf_read_count + nbytes -
 684                   async->buf_read_alloc_count) > 0) {
 685                 printk
 686                     ("comedi: attempted to read-free more bytes than have been read-allocated.\n");
 687                 nbytes = async->buf_read_alloc_count - async->buf_read_count;
 688         }
 689         async->buf_read_count += nbytes;
 690         async->buf_read_ptr += nbytes;
 691         async->buf_read_ptr %= async->prealloc_bufsz;
 692         return nbytes;
 693 }
 694
 695 void comedi_buf_memcpy_to(struct comedi_async *async, unsigned int offset,
 696                           const void *data, unsigned int num_bytes)
 697 {
 698         unsigned int write_ptr = async->buf_write_ptr + offset;
 699
 700         if (write_ptr >= async->prealloc_bufsz)
 701                 write_ptr %= async->prealloc_bufsz;
 702
 703         while (num_bytes) {
 704                 unsigned int block_size;
 705
 706                 if (write_ptr + num_bytes > async->prealloc_bufsz)
 707                         block_size = async->prealloc_bufsz - write_ptr;
 708                 else
 709                         block_size = num_bytes;
 710
 711                 memcpy(async->prealloc_buf + write_ptr, data, block_size);
 712
 713                 data += block_size;
 714                 num_bytes -= block_size;
 715
 716                 write_ptr = 0;
 717         }
 718 }
 719
 720 void comedi_buf_memcpy_from(struct comedi_async *async, unsigned int offset,
 721                             void *dest, unsigned int nbytes)
 722 {
 723         void *src;
 724         unsigned int read_ptr = async->buf_read_ptr + offset;
 725
 726         if (read_ptr >= async->prealloc_bufsz)
 727                 read_ptr %= async->prealloc_bufsz;
 728
 729         while (nbytes) {
 730                 unsigned int block_size;
 731
 732                 src = async->prealloc_buf + read_ptr;
 733
 734                 if (nbytes >= async->prealloc_bufsz - read_ptr)
 735                         block_size = async->prealloc_bufsz - read_ptr;
 736                 else
 737                         block_size = nbytes;
 738
 739                 memcpy(dest, src, block_size);
 740                 nbytes -= block_size;
 741                 dest += block_size;
 742                 read_ptr = 0;
 743         }
 744 }
 745
 746 unsigned int comedi_buf_read_n_available(struct comedi_async *async)
 747 {
 748         unsigned num_bytes;
 749
 750         if (async == NULL)
 751                 return 0;
 752         num_bytes = async->munge_count - async->buf_read_count;
 753         /* barrier insures the read of munge_count in this
 754            query occurs before any following reads of the buffer which
 755            might be based on the return value from this query.
 756          */
 757         smp_rmb();
 758         return num_bytes;
 759 }
 760
 761 int comedi_buf_get(struct comedi_async *async, short *x)
 762 {
 763         unsigned int n = comedi_buf_read_n_available(async);
 764
 765         if (n < sizeof(short))
 766                 return 0;
 767         comedi_buf_read_alloc(async, sizeof(short));
 768         *x = *(short *)(async->prealloc_buf + async->buf_read_ptr);
 769         comedi_buf_read_free(async, sizeof(short));
 770         return 1;
 771 }
 772
 773 int comedi_buf_put(struct comedi_async *async, short x)
 774 {
 775         unsigned int n = comedi_buf_write_alloc_strict(async, sizeof(short));
 776
 777         if (n < sizeof(short)) {
 778                 async->events |= COMEDI_CB_ERROR;
 779                 return 0;
 780         }
 781         *(short *)(async->prealloc_buf + async->buf_write_ptr) = x;
 782         comedi_buf_write_free(async, sizeof(short));
 783         return 1;
 784 }
 785
 786 void comedi_reset_async_buf(struct comedi_async *async)
 787 {
 788         async->buf_write_alloc_count = 0;
 789         async->buf_write_count = 0;
 790         async->buf_read_alloc_count = 0;
 791         async->buf_read_count = 0;
 792
 793         async->buf_write_ptr = 0;
 794         async->buf_read_ptr = 0;
 795
 796         async->cur_chan = 0;
 797         async->scan_progress = 0;
 798         async->munge_chan = 0;
 799         async->munge_count = 0;
 800         async->munge_ptr = 0;
 801
 802         async->events = 0;
 803 }
 804
 805 int comedi_auto_config(struct device *hardware_device, const char *board_name,
 806                        const int *options, unsigned num_options)
 807 {
 808         struct comedi_devconfig it;
 809         int minor;
 810         struct comedi_device_file_info *dev_file_info;
 811         int retval;
 812         unsigned *private_data = NULL;
 813
 814         if (!comedi_autoconfig) {
 815                 dev_set_drvdata(hardware_device, NULL);
 816                 return 0;
 817         }
 818
 819         minor = comedi_alloc_board_minor(hardware_device);
 820         if (minor < 0)
 821                 return minor;
 822
 823         private_data = kmalloc(sizeof(unsigned), GFP_KERNEL);
 824         if (private_data == NULL) {
 825                 retval = -ENOMEM;
 826                 goto cleanup;
 827         }
 828         *private_data = minor;
 829         dev_set_drvdata(hardware_device, private_data);
 830
 831         dev_file_info = comedi_get_device_file_info(minor);
 832
 833         memset(&it, 0, sizeof(it));
 834         strncpy(it.board_name, board_name, COMEDI_NAMELEN);
 835         it.board_name[COMEDI_NAMELEN - 1] = '\0';
 836         BUG_ON(num_options > COMEDI_NDEVCONFOPTS);
 837         memcpy(it.options, options, num_options * sizeof(int));
 838
 839         mutex_lock(&dev_file_info->device->mutex);
 840         retval = comedi_device_attach(dev_file_info->device, &it);
 841         mutex_unlock(&dev_file_info->device->mutex);
 842
 843 cleanup:
 844         if (retval < 0) {
 845                 kfree(private_data);
 846                 comedi_free_board_minor(minor);
 847         }
 848         return retval;
 849 }
 850
 851 void comedi_auto_unconfig(struct device *hardware_device)
 852 {
 853         unsigned *minor = (unsigned *)dev_get_drvdata(hardware_device);
 854         if (minor == NULL)
 855                 return;
 856
 857         BUG_ON(*minor >= COMEDI_NUM_BOARD_MINORS);
 858
 859         comedi_free_board_minor(*minor);
 860         dev_set_drvdata(hardware_device, NULL);
 861         kfree(minor);
 862 }
 863
 864 int comedi_pci_auto_config(struct pci_dev *pcidev, const char *board_name)
 865 {
 866         int options[2];
 867
 868         /*  pci bus */
 869         options[0] = pcidev->bus->number;
 870         /*  pci slot */
 871         options[1] = PCI_SLOT(pcidev->devfn);
 872
 873         return comedi_auto_config(&pcidev->dev, board_name,
 874                                   options, ARRAY_SIZE(options));
 875 }
 876
 877 void comedi_pci_auto_unconfig(struct pci_dev *pcidev)
 878 {
 879         comedi_auto_unconfig(&pcidev->dev);
 880 }
 881
 882 int comedi_usb_auto_config(struct usb_device *usbdev, const char *board_name)
 883 {
 884         BUG_ON(usbdev == NULL);
 885         return comedi_auto_config(&usbdev->dev, board_name, NULL, 0);
 886 }
 887
 888 void comedi_usb_auto_unconfig(struct usb_device *usbdev)
 889 {
 890         BUG_ON(usbdev == NULL);
 891         comedi_auto_unconfig(&usbdev->dev);
 892 }