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 <linux/device.h>
  28 #include <linux/module.h>
  29 #include <linux/pci.h>
  30 #include <linux/usb.h>
  31 #include <linux/errno.h>
  32 #include <linux/kconfig.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
  46 #include "comedidev.h"
  47 #include "comedi_internal.h"
  48
  49 static int postconfig(struct comedi_device *dev);
  50 static int insn_rw_emulate_bits(struct comedi_device *dev,
  51                                 struct comedi_subdevice *s,
  52                                 struct comedi_insn *insn, unsigned int *data);
  53 static void *comedi_recognize(struct comedi_driver *driv, const char *name);
  54 static void comedi_report_boards(struct comedi_driver *driv);
  55 static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s);
  56
  57 struct comedi_driver *comedi_drivers;
  58
  59 int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices)
  60 {
  61         struct comedi_subdevice *s;
  62         int i;
  63
  64         if (num_subdevices < 1)
  65                 return -EINVAL;
  66
  67         s = kcalloc(num_subdevices, sizeof(*s), GFP_KERNEL);
  68         if (!s)
  69                 return -ENOMEM;
  70         dev->subdevices = s;
  71         dev->n_subdevices = num_subdevices;
  72
  73         for (i = 0; i < num_subdevices; ++i) {
  74                 s = &dev->subdevices[i];
  75                 s->device = dev;
  76                 s->async_dma_dir = DMA_NONE;
  77                 spin_lock_init(&s->spin_lock);
  78                 s->minor = -1;
  79         }
  80         return 0;
  81 }
  82 EXPORT_SYMBOL_GPL(comedi_alloc_subdevices);
  83
  84 static void cleanup_device(struct comedi_device *dev)
  85 {
  86         int i;
  87         struct comedi_subdevice *s;
  88
  89         if (dev->subdevices) {
  90                 for (i = 0; i < dev->n_subdevices; i++) {
  91                         s = &dev->subdevices[i];
  92                         comedi_free_subdevice_minor(s);
  93                         if (s->async) {
  94                                 comedi_buf_alloc(dev, s, 0);
  95                                 kfree(s->async);
  96                         }
  97                 }
  98                 kfree(dev->subdevices);
  99                 dev->subdevices = NULL;
 100                 dev->n_subdevices = 0;
 101         }
 102         kfree(dev->private);
 103         dev->private = NULL;
 104         dev->driver = NULL;
 105         dev->board_name = NULL;
 106         dev->board_ptr = NULL;
 107         dev->iobase = 0;
 108         dev->irq = 0;
 109         dev->read_subdev = NULL;
 110         dev->write_subdev = NULL;
 111         dev->open = NULL;
 112         dev->close = NULL;
 113         comedi_set_hw_dev(dev, NULL);
 114 }
 115
 116 static void __comedi_device_detach(struct comedi_device *dev)
 117 {
 118         dev->attached = 0;
 119         if (dev->driver)
 120                 dev->driver->detach(dev);
 121         else
 122                 dev_warn(dev->class_dev,
 123                          "BUG: dev->driver=NULL in comedi_device_detach()\n");
 124         cleanup_device(dev);
 125 }
 126
 127 void comedi_device_detach(struct comedi_device *dev)
 128 {
 129         if (!dev->attached)
 130                 return;
 131         __comedi_device_detach(dev);
 132 }
 133
 134 /* do a little post-config cleanup */
 135 /* called with module refcount incremented, decrements it */
 136 static int comedi_device_postconfig(struct comedi_device *dev)
 137 {
 138         int ret = postconfig(dev);
 139         module_put(dev->driver->module);
 140         if (ret < 0) {
 141                 __comedi_device_detach(dev);
 142                 return ret;
 143         }
 144         if (!dev->board_name) {
 145                 dev_warn(dev->class_dev, "BUG: dev->board_name=NULL\n");
 146                 dev->board_name = "BUG";
 147         }
 148         smp_wmb();
 149         dev->attached = 1;
 150         return 0;
 151 }
 152
 153 int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 154 {
 155         struct comedi_driver *driv;
 156         int ret;
 157
 158         if (dev->attached)
 159                 return -EBUSY;
 160
 161         for (driv = comedi_drivers; driv; driv = driv->next) {
 162                 if (!try_module_get(driv->module))
 163                         continue;
 164                 if (driv->num_names) {
 165                         dev->board_ptr = comedi_recognize(driv, it->board_name);
 166                         if (dev->board_ptr)
 167                                 break;
 168                 } else if (strcmp(driv->driver_name, it->board_name) == 0)
 169                         break;
 170                 module_put(driv->module);
 171         }
 172         if (driv == NULL) {
 173                 /*  recognize has failed if we get here */
 174                 /*  report valid board names before returning error */
 175                 for (driv = comedi_drivers; driv; driv = driv->next) {
 176                         if (!try_module_get(driv->module))
 177                                 continue;
 178                         comedi_report_boards(driv);
 179                         module_put(driv->module);
 180                 }
 181                 return -EIO;
 182         }
 183         if (driv->attach == NULL) {
 184                 /* driver does not support manual configuration */
 185                 dev_warn(dev->class_dev,
 186                          "driver '%s' does not support attach using comedi_config\n",
 187                          driv->driver_name);
 188                 module_put(driv->module);
 189                 return -ENOSYS;
 190         }
 191         /* initialize dev->driver here so
 192          * comedi_error() can be called from attach */
 193         dev->driver = driv;
 194         ret = driv->attach(dev, it);
 195         if (ret < 0) {
 196                 module_put(dev->driver->module);
 197                 __comedi_device_detach(dev);
 198                 return ret;
 199         }
 200         return comedi_device_postconfig(dev);
 201 }
 202
 203 int comedi_driver_register(struct comedi_driver *driver)
 204 {
 205         driver->next = comedi_drivers;
 206         comedi_drivers = driver;
 207
 208         return 0;
 209 }
 210 EXPORT_SYMBOL(comedi_driver_register);
 211
 212 int comedi_driver_unregister(struct comedi_driver *driver)
 213 {
 214         struct comedi_driver *prev;
 215         int i;
 216
 217         /* check for devices using this driver */
 218         for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
 219                 struct comedi_device_file_info *dev_file_info =
 220                     comedi_get_device_file_info(i);
 221                 struct comedi_device *dev;
 222
 223                 if (dev_file_info == NULL)
 224                         continue;
 225                 dev = dev_file_info->device;
 226
 227                 mutex_lock(&dev->mutex);
 228                 if (dev->attached && dev->driver == driver) {
 229                         if (dev->use_count)
 230                                 dev_warn(dev->class_dev,
 231                                          "BUG! detaching device with use_count=%d\n",
 232                                          dev->use_count);
 233                         comedi_device_detach(dev);
 234                 }
 235                 mutex_unlock(&dev->mutex);
 236         }
 237
 238         if (comedi_drivers == driver) {
 239                 comedi_drivers = driver->next;
 240                 return 0;
 241         }
 242
 243         for (prev = comedi_drivers; prev->next; prev = prev->next) {
 244                 if (prev->next == driver) {
 245                         prev->next = driver->next;
 246                         return 0;
 247                 }
 248         }
 249         return -EINVAL;
 250 }
 251 EXPORT_SYMBOL(comedi_driver_unregister);
 252
 253 static int postconfig(struct comedi_device *dev)
 254 {
 255         int i;
 256         struct comedi_subdevice *s;
 257         struct comedi_async *async = NULL;
 258         int ret;
 259
 260         for (i = 0; i < dev->n_subdevices; i++) {
 261                 s = &dev->subdevices[i];
 262
 263                 if (s->type == COMEDI_SUBD_UNUSED)
 264                         continue;
 265
 266                 if (s->len_chanlist == 0)
 267                         s->len_chanlist = 1;
 268
 269                 if (s->do_cmd) {
 270                         unsigned int buf_size;
 271
 272                         BUG_ON((s->subdev_flags & (SDF_CMD_READ |
 273                                                    SDF_CMD_WRITE)) == 0);
 274                         BUG_ON(!s->do_cmdtest);
 275
 276                         async =
 277                             kzalloc(sizeof(struct comedi_async), GFP_KERNEL);
 278                         if (async == NULL) {
 279                                 dev_warn(dev->class_dev,
 280                                          "failed to allocate async struct\n");
 281                                 return -ENOMEM;
 282                         }
 283                         init_waitqueue_head(&async->wait_head);
 284                         async->subdevice = s;
 285                         s->async = async;
 286
 287                         async->max_bufsize =
 288                                 comedi_default_buf_maxsize_kb * 1024;
 289                         buf_size = comedi_default_buf_size_kb * 1024;
 290                         if (buf_size > async->max_bufsize)
 291                                 buf_size = async->max_bufsize;
 292
 293                         async->prealloc_buf = NULL;
 294                         async->prealloc_bufsz = 0;
 295                         if (comedi_buf_alloc(dev, s, buf_size) < 0) {
 296                                 dev_warn(dev->class_dev,
 297                                          "Buffer allocation failed\n");
 298                                 return -ENOMEM;
 299                         }
 300                         if (s->buf_change) {
 301                                 ret = s->buf_change(dev, s, buf_size);
 302                                 if (ret < 0)
 303                                         return ret;
 304                         }
 305                         comedi_alloc_subdevice_minor(dev, s);
 306                 }
 307
 308                 if (!s->range_table && !s->range_table_list)
 309                         s->range_table = &range_unknown;
 310
 311                 if (!s->insn_read && s->insn_bits)
 312                         s->insn_read = insn_rw_emulate_bits;
 313                 if (!s->insn_write && s->insn_bits)
 314                         s->insn_write = insn_rw_emulate_bits;
 315
 316                 if (!s->insn_read)
 317                         s->insn_read = insn_inval;
 318                 if (!s->insn_write)
 319                         s->insn_write = insn_inval;
 320                 if (!s->insn_bits)
 321                         s->insn_bits = insn_inval;
 322                 if (!s->insn_config)
 323                         s->insn_config = insn_inval;
 324
 325                 if (!s->poll)
 326                         s->poll = poll_invalid;
 327         }
 328
 329         return 0;
 330 }
 331
 332 /*
 333  * Generic recognize function for drivers that register their supported
 334  * board names.
 335  *
 336  * 'driv->board_name' points to a 'const char *' member within the
 337  * zeroth element of an array of some private board information
 338  * structure, say 'struct foo_board' containing a member 'const char
 339  * *board_name' that is initialized to point to a board name string that
 340  * is one of the candidates matched against this function's 'name'
 341  * parameter.
 342  *
 343  * 'driv->offset' is the size of the private board information
 344  * structure, say 'sizeof(struct foo_board)', and 'driv->num_names' is
 345  * the length of the array of private board information structures.
 346  *
 347  * If one of the board names in the array of private board information
 348  * structures matches the name supplied to this function, the function
 349  * returns a pointer to the pointer to the board name, otherwise it
 350  * returns NULL.  The return value ends up in the 'board_ptr' member of
 351  * a 'struct comedi_device' that the low-level comedi driver's
 352  * 'attach()' hook can convert to a point to a particular element of its
 353  * array of private board information structures by subtracting the
 354  * offset of the member that points to the board name.  (No subtraction
 355  * is required if the board name pointer is the first member of the
 356  * private board information structure, which is generally the case.)
 357  */
 358 static void *comedi_recognize(struct comedi_driver *driv, const char *name)
 359 {
 360         char **name_ptr = (char **)driv->board_name;
 361         int i;
 362
 363         for (i = 0; i < driv->num_names; i++) {
 364                 if (strcmp(*name_ptr, name) == 0)
 365                         return name_ptr;
 366                 name_ptr = (void *)name_ptr + driv->offset;
 367         }
 368
 369         return NULL;
 370 }
 371
 372 static void comedi_report_boards(struct comedi_driver *driv)
 373 {
 374         unsigned int i;
 375         const char *const *name_ptr;
 376
 377         pr_info("comedi: valid board names for %s driver are:\n",
 378                 driv->driver_name);
 379
 380         name_ptr = driv->board_name;
 381         for (i = 0; i < driv->num_names; i++) {
 382                 pr_info(" %s\n", *name_ptr);
 383                 name_ptr = (const char **)((char *)name_ptr + driv->offset);
 384         }
 385
 386         if (driv->num_names == 0)
 387                 pr_info(" %s\n", driv->driver_name);
 388 }
 389
 390 static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s)
 391 {
 392         return -EINVAL;
 393 }
 394
 395 int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s,
 396                struct comedi_insn *insn, unsigned int *data)
 397 {
 398         return -EINVAL;
 399 }
 400
 401 static int insn_rw_emulate_bits(struct comedi_device *dev,
 402                                 struct comedi_subdevice *s,
 403                                 struct comedi_insn *insn, unsigned int *data)
 404 {
 405         struct comedi_insn new_insn;
 406         int ret;
 407         static const unsigned channels_per_bitfield = 32;
 408
 409         unsigned chan = CR_CHAN(insn->chanspec);
 410         const unsigned base_bitfield_channel =
 411             (chan < channels_per_bitfield) ? 0 : chan;
 412         unsigned int new_data[2];
 413         memset(new_data, 0, sizeof(new_data));
 414         memset(&new_insn, 0, sizeof(new_insn));
 415         new_insn.insn = INSN_BITS;
 416         new_insn.chanspec = base_bitfield_channel;
 417         new_insn.n = 2;
 418         new_insn.subdev = insn->subdev;
 419
 420         if (insn->insn == INSN_WRITE) {
 421                 if (!(s->subdev_flags & SDF_WRITABLE))
 422                         return -EINVAL;
 423                 new_data[0] = 1 << (chan - base_bitfield_channel); /* mask */
 424                 new_data[1] = data[0] ? (1 << (chan - base_bitfield_channel))
 425                               : 0; /* bits */
 426         }
 427
 428         ret = s->insn_bits(dev, s, &new_insn, new_data);
 429         if (ret < 0)
 430                 return ret;
 431
 432         if (insn->insn == INSN_READ)
 433                 data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1;
 434
 435         return 1;
 436 }
 437
 438 int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
 439                      unsigned long new_size)
 440 {
 441         struct comedi_async *async = s->async;
 442
 443         /* Round up new_size to multiple of PAGE_SIZE */
 444         new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
 445
 446         /* if no change is required, do nothing */
 447         if (async->prealloc_buf && async->prealloc_bufsz == new_size)
 448                 return 0;
 449
 450         /*  deallocate old buffer */
 451         if (async->prealloc_buf) {
 452                 vunmap(async->prealloc_buf);
 453                 async->prealloc_buf = NULL;
 454                 async->prealloc_bufsz = 0;
 455         }
 456         if (async->buf_page_list) {
 457                 unsigned i;
 458                 for (i = 0; i < async->n_buf_pages; ++i) {
 459                         if (async->buf_page_list[i].virt_addr) {
 460                                 clear_bit(PG_reserved,
 461                                         &(virt_to_page(async->buf_page_list[i].
 462                                                         virt_addr)->flags));
 463                                 if (s->async_dma_dir != DMA_NONE) {
 464                                         dma_free_coherent(dev->hw_dev,
 465                                                           PAGE_SIZE,
 466                                                           async->
 467                                                           buf_page_list
 468                                                           [i].virt_addr,
 469                                                           async->
 470                                                           buf_page_list
 471                                                           [i].dma_addr);
 472                                 } else {
 473                                         free_page((unsigned long)
 474                                                   async->buf_page_list[i].
 475                                                   virt_addr);
 476                                 }
 477                         }
 478                 }
 479                 vfree(async->buf_page_list);
 480                 async->buf_page_list = NULL;
 481                 async->n_buf_pages = 0;
 482         }
 483         /*  allocate new buffer */
 484         if (new_size) {
 485                 unsigned i = 0;
 486                 unsigned n_pages = new_size >> PAGE_SHIFT;
 487                 struct page **pages = NULL;
 488
 489                 async->buf_page_list =
 490                     vzalloc(sizeof(struct comedi_buf_page) * n_pages);
 491                 if (async->buf_page_list)
 492                         pages = vmalloc(sizeof(struct page *) * n_pages);
 493
 494                 if (pages) {
 495                         for (i = 0; i < n_pages; i++) {
 496                                 if (s->async_dma_dir != DMA_NONE) {
 497                                         async->buf_page_list[i].virt_addr =
 498                                             dma_alloc_coherent(dev->hw_dev,
 499                                                                PAGE_SIZE,
 500                                                                &async->
 501                                                                buf_page_list
 502                                                                [i].dma_addr,
 503                                                                GFP_KERNEL |
 504                                                                __GFP_COMP);
 505                                 } else {
 506                                         async->buf_page_list[i].virt_addr =
 507                                             (void *)
 508                                             get_zeroed_page(GFP_KERNEL);
 509                                 }
 510                                 if (async->buf_page_list[i].virt_addr == NULL)
 511                                         break;
 512
 513                                 set_bit(PG_reserved,
 514                                         &(virt_to_page(async->buf_page_list[i].
 515                                                         virt_addr)->flags));
 516                                 pages[i] = virt_to_page(async->buf_page_list[i].
 517                                                                 virt_addr);
 518                         }
 519                 }
 520                 if (i == n_pages) {
 521                         async->prealloc_buf =
 522 #ifdef PAGE_KERNEL_NOCACHE
 523                             vmap(pages, n_pages, VM_MAP, PAGE_KERNEL_NOCACHE);
 524 #else
 525                             vmap(pages, n_pages, VM_MAP, PAGE_KERNEL);
 526 #endif
 527                 }
 528                 vfree(pages);
 529
 530                 if (async->prealloc_buf == NULL) {
 531                         /* Some allocation failed above. */
 532                         if (async->buf_page_list) {
 533                                 for (i = 0; i < n_pages; i++) {
 534                                         if (async->buf_page_list[i].virt_addr ==
 535                                             NULL) {
 536                                                 break;
 537                                         }
 538                                         clear_bit(PG_reserved,
 539                                                 &(virt_to_page(async->
 540                                                         buf_page_list[i].
 541                                                         virt_addr)->flags));
 542                                         if (s->async_dma_dir != DMA_NONE) {
 543                                                 dma_free_coherent(dev->hw_dev,
 544                                                                   PAGE_SIZE,
 545                                                                   async->
 546                                                                   buf_page_list
 547                                                                   [i].virt_addr,
 548                                                                   async->
 549                                                                   buf_page_list
 550                                                                   [i].dma_addr);
 551                                         } else {
 552                                                 free_page((unsigned long)
 553                                                           async->buf_page_list
 554                                                           [i].virt_addr);
 555                                         }
 556                                 }
 557                                 vfree(async->buf_page_list);
 558                                 async->buf_page_list = NULL;
 559                         }
 560                         return -ENOMEM;
 561                 }
 562                 async->n_buf_pages = n_pages;
 563         }
 564         async->prealloc_bufsz = new_size;
 565
 566         return 0;
 567 }
 568
 569 /* munging is applied to data by core as it passes between user
 570  * and kernel space */
 571 static unsigned int comedi_buf_munge(struct comedi_async *async,
 572                                      unsigned int num_bytes)
 573 {
 574         struct comedi_subdevice *s = async->subdevice;
 575         unsigned int count = 0;
 576         const unsigned num_sample_bytes = bytes_per_sample(s);
 577
 578         if (s->munge == NULL || (async->cmd.flags & CMDF_RAWDATA)) {
 579                 async->munge_count += num_bytes;
 580                 BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
 581                 return num_bytes;
 582         }
 583         /* don't munge partial samples */
 584         num_bytes -= num_bytes % num_sample_bytes;
 585         while (count < num_bytes) {
 586                 int block_size;
 587
 588                 block_size = num_bytes - count;
 589                 if (block_size < 0) {
 590                         dev_warn(s->device->class_dev,
 591                                  "%s: %s: bug! block_size is negative\n",
 592                                  __FILE__, __func__);
 593                         break;
 594                 }
 595                 if ((int)(async->munge_ptr + block_size -
 596                           async->prealloc_bufsz) > 0)
 597                         block_size = async->prealloc_bufsz - async->munge_ptr;
 598
 599                 s->munge(s->device, s, async->prealloc_buf + async->munge_ptr,
 600                          block_size, async->munge_chan);
 601
 602                 smp_wmb();      /* barrier insures data is munged in buffer
 603                                  * before munge_count is incremented */
 604
 605                 async->munge_chan += block_size / num_sample_bytes;
 606                 async->munge_chan %= async->cmd.chanlist_len;
 607                 async->munge_count += block_size;
 608                 async->munge_ptr += block_size;
 609                 async->munge_ptr %= async->prealloc_bufsz;
 610                 count += block_size;
 611         }
 612         BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
 613         return count;
 614 }
 615
 616 unsigned int comedi_buf_write_n_available(struct comedi_async *async)
 617 {
 618         unsigned int free_end;
 619         unsigned int nbytes;
 620
 621         if (async == NULL)
 622                 return 0;
 623
 624         free_end = async->buf_read_count + async->prealloc_bufsz;
 625         nbytes = free_end - async->buf_write_alloc_count;
 626         nbytes -= nbytes % bytes_per_sample(async->subdevice);
 627         /* barrier insures the read of buf_read_count in this
 628            query occurs before any following writes to the buffer which
 629            might be based on the return value from this query.
 630          */
 631         smp_mb();
 632         return nbytes;
 633 }
 634
 635 /* allocates chunk for the writer from free buffer space */
 636 unsigned int comedi_buf_write_alloc(struct comedi_async *async,
 637                                     unsigned int nbytes)
 638 {
 639         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 640
 641         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0)
 642                 nbytes = free_end - async->buf_write_alloc_count;
 643
 644         async->buf_write_alloc_count += nbytes;
 645         /* barrier insures the read of buf_read_count above occurs before
 646            we write data to the write-alloc'ed buffer space */
 647         smp_mb();
 648         return nbytes;
 649 }
 650 EXPORT_SYMBOL(comedi_buf_write_alloc);
 651
 652 /* allocates nothing unless it can completely fulfill the request */
 653 unsigned int comedi_buf_write_alloc_strict(struct comedi_async *async,
 654                                            unsigned int nbytes)
 655 {
 656         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 657
 658         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0)
 659                 nbytes = 0;
 660
 661         async->buf_write_alloc_count += nbytes;
 662         /* barrier insures the read of buf_read_count above occurs before
 663            we write data to the write-alloc'ed buffer space */
 664         smp_mb();
 665         return nbytes;
 666 }
 667
 668 /* transfers a chunk from writer to filled buffer space */
 669 unsigned comedi_buf_write_free(struct comedi_async *async, unsigned int nbytes)
 670 {
 671         if ((int)(async->buf_write_count + nbytes -
 672                   async->buf_write_alloc_count) > 0) {
 673                 dev_info(async->subdevice->device->class_dev,
 674                          "attempted to write-free more bytes than have been write-allocated.\n");
 675                 nbytes = async->buf_write_alloc_count - async->buf_write_count;
 676         }
 677         async->buf_write_count += nbytes;
 678         async->buf_write_ptr += nbytes;
 679         comedi_buf_munge(async, async->buf_write_count - async->munge_count);
 680         if (async->buf_write_ptr >= async->prealloc_bufsz)
 681                 async->buf_write_ptr %= async->prealloc_bufsz;
 682
 683         return nbytes;
 684 }
 685 EXPORT_SYMBOL(comedi_buf_write_free);
 686
 687 /* allocates a chunk for the reader from filled (and munged) buffer space */
 688 unsigned comedi_buf_read_alloc(struct comedi_async *async, unsigned nbytes)
 689 {
 690         if ((int)(async->buf_read_alloc_count + nbytes - async->munge_count) >
 691             0) {
 692                 nbytes = async->munge_count - async->buf_read_alloc_count;
 693         }
 694         async->buf_read_alloc_count += nbytes;
 695         /* barrier insures read of munge_count occurs before we actually read
 696            data out of buffer */
 697         smp_rmb();
 698         return nbytes;
 699 }
 700 EXPORT_SYMBOL(comedi_buf_read_alloc);
 701
 702 /* transfers control of a chunk from reader to free buffer space */
 703 unsigned comedi_buf_read_free(struct comedi_async *async, unsigned int nbytes)
 704 {
 705         /* barrier insures data has been read out of
 706          * buffer before read count is incremented */
 707         smp_mb();
 708         if ((int)(async->buf_read_count + nbytes -
 709                   async->buf_read_alloc_count) > 0) {
 710                 dev_info(async->subdevice->device->class_dev,
 711                          "attempted to read-free more bytes than have been read-allocated.\n");
 712                 nbytes = async->buf_read_alloc_count - async->buf_read_count;
 713         }
 714         async->buf_read_count += nbytes;
 715         async->buf_read_ptr += nbytes;
 716         async->buf_read_ptr %= async->prealloc_bufsz;
 717         return nbytes;
 718 }
 719 EXPORT_SYMBOL(comedi_buf_read_free);
 720
 721 void comedi_buf_memcpy_to(struct comedi_async *async, unsigned int offset,
 722                           const void *data, unsigned int num_bytes)
 723 {
 724         unsigned int write_ptr = async->buf_write_ptr + offset;
 725
 726         if (write_ptr >= async->prealloc_bufsz)
 727                 write_ptr %= async->prealloc_bufsz;
 728
 729         while (num_bytes) {
 730                 unsigned int block_size;
 731
 732                 if (write_ptr + num_bytes > async->prealloc_bufsz)
 733                         block_size = async->prealloc_bufsz - write_ptr;
 734                 else
 735                         block_size = num_bytes;
 736
 737                 memcpy(async->prealloc_buf + write_ptr, data, block_size);
 738
 739                 data += block_size;
 740                 num_bytes -= block_size;
 741
 742                 write_ptr = 0;
 743         }
 744 }
 745 EXPORT_SYMBOL(comedi_buf_memcpy_to);
 746
 747 void comedi_buf_memcpy_from(struct comedi_async *async, unsigned int offset,
 748                             void *dest, unsigned int nbytes)
 749 {
 750         void *src;
 751         unsigned int read_ptr = async->buf_read_ptr + offset;
 752
 753         if (read_ptr >= async->prealloc_bufsz)
 754                 read_ptr %= async->prealloc_bufsz;
 755
 756         while (nbytes) {
 757                 unsigned int block_size;
 758
 759                 src = async->prealloc_buf + read_ptr;
 760
 761                 if (nbytes >= async->prealloc_bufsz - read_ptr)
 762                         block_size = async->prealloc_bufsz - read_ptr;
 763                 else
 764                         block_size = nbytes;
 765
 766                 memcpy(dest, src, block_size);
 767                 nbytes -= block_size;
 768                 dest += block_size;
 769                 read_ptr = 0;
 770         }
 771 }
 772 EXPORT_SYMBOL(comedi_buf_memcpy_from);
 773
 774 unsigned int comedi_buf_read_n_available(struct comedi_async *async)
 775 {
 776         unsigned num_bytes;
 777
 778         if (async == NULL)
 779                 return 0;
 780         num_bytes = async->munge_count - async->buf_read_count;
 781         /* barrier insures the read of munge_count in this
 782            query occurs before any following reads of the buffer which
 783            might be based on the return value from this query.
 784          */
 785         smp_rmb();
 786         return num_bytes;
 787 }
 788 EXPORT_SYMBOL(comedi_buf_read_n_available);
 789
 790 int comedi_buf_get(struct comedi_async *async, short *x)
 791 {
 792         unsigned int n = comedi_buf_read_n_available(async);
 793
 794         if (n < sizeof(short))
 795                 return 0;
 796         comedi_buf_read_alloc(async, sizeof(short));
 797         *x = *(short *)(async->prealloc_buf + async->buf_read_ptr);
 798         comedi_buf_read_free(async, sizeof(short));
 799         return 1;
 800 }
 801 EXPORT_SYMBOL(comedi_buf_get);
 802
 803 int comedi_buf_put(struct comedi_async *async, short x)
 804 {
 805         unsigned int n = comedi_buf_write_alloc_strict(async, sizeof(short));
 806
 807         if (n < sizeof(short)) {
 808                 async->events |= COMEDI_CB_ERROR;
 809                 return 0;
 810         }
 811         *(short *)(async->prealloc_buf + async->buf_write_ptr) = x;
 812         comedi_buf_write_free(async, sizeof(short));
 813         return 1;
 814 }
 815 EXPORT_SYMBOL(comedi_buf_put);
 816
 817 void comedi_reset_async_buf(struct comedi_async *async)
 818 {
 819         async->buf_write_alloc_count = 0;
 820         async->buf_write_count = 0;
 821         async->buf_read_alloc_count = 0;
 822         async->buf_read_count = 0;
 823
 824         async->buf_write_ptr = 0;
 825         async->buf_read_ptr = 0;
 826
 827         async->cur_chan = 0;
 828         async->scan_progress = 0;
 829         async->munge_chan = 0;
 830         async->munge_count = 0;
 831         async->munge_ptr = 0;
 832
 833         async->events = 0;
 834 }
 835
 836 int comedi_auto_config(struct device *hardware_device,
 837                        struct comedi_driver *driver, unsigned long context)
 838 {
 839         int minor;
 840         struct comedi_device_file_info *dev_file_info;
 841         struct comedi_device *comedi_dev;
 842         int ret;
 843
 844         if (!comedi_autoconfig)
 845                 return 0;
 846
 847         if (!driver->auto_attach) {
 848                 dev_warn(hardware_device,
 849                          "BUG! comedi driver '%s' has no auto_attach handler\n",
 850                          driver->driver_name);
 851                 return -EINVAL;
 852         }
 853
 854         minor = comedi_alloc_board_minor(hardware_device);
 855         if (minor < 0)
 856                 return minor;
 857
 858         dev_file_info = comedi_get_device_file_info(minor);
 859         comedi_dev = dev_file_info->device;
 860
 861         mutex_lock(&comedi_dev->mutex);
 862         if (comedi_dev->attached)
 863                 ret = -EBUSY;
 864         else if (!try_module_get(driver->module))
 865                 ret = -EIO;
 866         else {
 867                 comedi_set_hw_dev(comedi_dev, hardware_device);
 868                 comedi_dev->driver = driver;
 869                 ret = driver->auto_attach(comedi_dev, context);
 870                 if (ret < 0) {
 871                         module_put(driver->module);
 872                         __comedi_device_detach(comedi_dev);
 873                 } else {
 874                         ret = comedi_device_postconfig(comedi_dev);
 875                 }
 876         }
 877         mutex_unlock(&comedi_dev->mutex);
 878
 879         if (ret < 0)
 880                 comedi_free_board_minor(minor);
 881         return ret;
 882 }
 883 EXPORT_SYMBOL_GPL(comedi_auto_config);
 884
 885 void comedi_auto_unconfig(struct device *hardware_device)
 886 {
 887         int minor;
 888
 889         if (hardware_device == NULL)
 890                 return;
 891         minor = comedi_find_board_minor(hardware_device);
 892         if (minor < 0)
 893                 return;
 894         BUG_ON(minor >= COMEDI_NUM_BOARD_MINORS);
 895         comedi_free_board_minor(minor);
 896 }
 897 EXPORT_SYMBOL_GPL(comedi_auto_unconfig);
 898
 899 /**
 900  * comedi_pci_enable() - Enable the PCI device and request the regions.
 901  * @pdev: pci_dev struct
 902  * @res_name: name for the requested reqource
 903  */
 904 int comedi_pci_enable(struct pci_dev *pdev, const char *res_name)
 905 {
 906         int rc;
 907
 908         rc = pci_enable_device(pdev);
 909         if (rc < 0)
 910                 return rc;
 911
 912         rc = pci_request_regions(pdev, res_name);
 913         if (rc < 0)
 914                 pci_disable_device(pdev);
 915
 916         return rc;
 917 }
 918 EXPORT_SYMBOL_GPL(comedi_pci_enable);
 919
 920 /**
 921  * comedi_pci_disable() - Release the regions and disable the PCI device.
 922  * @pdev: pci_dev struct
 923  *
 924  * This must be matched with a previous successful call to comedi_pci_enable().
 925  */
 926 void comedi_pci_disable(struct pci_dev *pdev)
 927 {
 928         pci_release_regions(pdev);
 929         pci_disable_device(pdev);
 930 }
 931 EXPORT_SYMBOL_GPL(comedi_pci_disable);
 932
 933 int comedi_pci_driver_register(struct comedi_driver *comedi_driver,
 934                 struct pci_driver *pci_driver)
 935 {
 936         int ret;
 937
 938         ret = comedi_driver_register(comedi_driver);
 939         if (ret < 0)
 940                 return ret;
 941
 942         /* FIXME: Remove this test after auditing all comedi pci drivers */
 943         if (!pci_driver->name)
 944                 pci_driver->name = comedi_driver->driver_name;
 945
 946         ret = pci_register_driver(pci_driver);
 947         if (ret < 0) {
 948                 comedi_driver_unregister(comedi_driver);
 949                 return ret;
 950         }
 951
 952         return 0;
 953 }
 954 EXPORT_SYMBOL_GPL(comedi_pci_driver_register);
 955
 956 void comedi_pci_driver_unregister(struct comedi_driver *comedi_driver,
 957                 struct pci_driver *pci_driver)
 958 {
 959         pci_unregister_driver(pci_driver);
 960         comedi_driver_unregister(comedi_driver);
 961 }
 962 EXPORT_SYMBOL_GPL(comedi_pci_driver_unregister);
 963
 964 #if IS_ENABLED(CONFIG_USB)
 965
 966 int comedi_usb_driver_register(struct comedi_driver *comedi_driver,
 967                 struct usb_driver *usb_driver)
 968 {
 969         int ret;
 970
 971         ret = comedi_driver_register(comedi_driver);
 972         if (ret < 0)
 973                 return ret;
 974
 975         ret = usb_register(usb_driver);
 976         if (ret < 0) {
 977                 comedi_driver_unregister(comedi_driver);
 978                 return ret;
 979         }
 980
 981         return 0;
 982 }
 983 EXPORT_SYMBOL_GPL(comedi_usb_driver_register);
 984
 985 void comedi_usb_driver_unregister(struct comedi_driver *comedi_driver,
 986                 struct usb_driver *usb_driver)
 987 {
 988         usb_deregister(usb_driver);
 989         comedi_driver_unregister(comedi_driver);
 990 }
 991 EXPORT_SYMBOL_GPL(comedi_usb_driver_unregister);
 992
 993 #endif