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 #include <linux/device.h>
  25 #include <linux/module.h>
  26 #include <linux/pci.h>
  27 #include <linux/usb.h>
  28 #include <linux/errno.h>
  29 #include <linux/kconfig.h>
  30 #include <linux/kernel.h>
  31 #include <linux/sched.h>
  32 #include <linux/fcntl.h>
  33 #include <linux/delay.h>
  34 #include <linux/ioport.h>
  35 #include <linux/mm.h>
  36 #include <linux/slab.h>
  37 #include <linux/highmem.h>      /* for SuSE brokenness */
  38 #include <linux/vmalloc.h>
  39 #include <linux/cdev.h>
  40 #include <linux/dma-mapping.h>
  41 #include <linux/io.h>
  42
  43 #include "comedidev.h"
  44 #include "comedi_internal.h"
  45
  46 static int postconfig(struct comedi_device *dev);
  47 static int insn_rw_emulate_bits(struct comedi_device *dev,
  48                                 struct comedi_subdevice *s,
  49                                 struct comedi_insn *insn, unsigned int *data);
  50 static void *comedi_recognize(struct comedi_driver *driv, const char *name);
  51 static void comedi_report_boards(struct comedi_driver *driv);
  52 static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s);
  53
  54 struct comedi_driver *comedi_drivers;
  55
  56 int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices)
  57 {
  58         struct comedi_subdevice *s;
  59         int i;
  60
  61         if (num_subdevices < 1)
  62                 return -EINVAL;
  63
  64         s = kcalloc(num_subdevices, sizeof(*s), GFP_KERNEL);
  65         if (!s)
  66                 return -ENOMEM;
  67         dev->subdevices = s;
  68         dev->n_subdevices = num_subdevices;
  69
  70         for (i = 0; i < num_subdevices; ++i) {
  71                 s = &dev->subdevices[i];
  72                 s->device = dev;
  73                 s->async_dma_dir = DMA_NONE;
  74                 spin_lock_init(&s->spin_lock);
  75                 s->minor = -1;
  76         }
  77         return 0;
  78 }
  79 EXPORT_SYMBOL_GPL(comedi_alloc_subdevices);
  80
  81 static void cleanup_device(struct comedi_device *dev)
  82 {
  83         int i;
  84         struct comedi_subdevice *s;
  85
  86         if (dev->subdevices) {
  87                 for (i = 0; i < dev->n_subdevices; i++) {
  88                         s = &dev->subdevices[i];
  89                         comedi_free_subdevice_minor(s);
  90                         if (s->async) {
  91                                 comedi_buf_alloc(dev, s, 0);
  92                                 kfree(s->async);
  93                         }
  94                 }
  95                 kfree(dev->subdevices);
  96                 dev->subdevices = NULL;
  97                 dev->n_subdevices = 0;
  98         }
  99         kfree(dev->private);
 100         dev->private = NULL;
 101         dev->driver = NULL;
 102         dev->board_name = NULL;
 103         dev->board_ptr = NULL;
 104         dev->iobase = 0;
 105         dev->irq = 0;
 106         dev->read_subdev = NULL;
 107         dev->write_subdev = NULL;
 108         dev->open = NULL;
 109         dev->close = NULL;
 110         comedi_set_hw_dev(dev, NULL);
 111 }
 112
 113 static void __comedi_device_detach(struct comedi_device *dev)
 114 {
 115         dev->attached = 0;
 116         if (dev->driver)
 117                 dev->driver->detach(dev);
 118         else
 119                 dev_warn(dev->class_dev,
 120                          "BUG: dev->driver=NULL in comedi_device_detach()\n");
 121         cleanup_device(dev);
 122 }
 123
 124 void comedi_device_detach(struct comedi_device *dev)
 125 {
 126         if (!dev->attached)
 127                 return;
 128         __comedi_device_detach(dev);
 129 }
 130
 131 /* do a little post-config cleanup */
 132 /* called with module refcount incremented, decrements it */
 133 static int comedi_device_postconfig(struct comedi_device *dev)
 134 {
 135         int ret = postconfig(dev);
 136         module_put(dev->driver->module);
 137         if (ret < 0) {
 138                 __comedi_device_detach(dev);
 139                 return ret;
 140         }
 141         if (!dev->board_name) {
 142                 dev_warn(dev->class_dev, "BUG: dev->board_name=NULL\n");
 143                 dev->board_name = "BUG";
 144         }
 145         smp_wmb();
 146         dev->attached = 1;
 147         return 0;
 148 }
 149
 150 int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 151 {
 152         struct comedi_driver *driv;
 153         int ret;
 154
 155         if (dev->attached)
 156                 return -EBUSY;
 157
 158         for (driv = comedi_drivers; driv; driv = driv->next) {
 159                 if (!try_module_get(driv->module))
 160                         continue;
 161                 if (driv->num_names) {
 162                         dev->board_ptr = comedi_recognize(driv, it->board_name);
 163                         if (dev->board_ptr)
 164                                 break;
 165                 } else if (strcmp(driv->driver_name, it->board_name) == 0)
 166                         break;
 167                 module_put(driv->module);
 168         }
 169         if (driv == NULL) {
 170                 /*  recognize has failed if we get here */
 171                 /*  report valid board names before returning error */
 172                 for (driv = comedi_drivers; driv; driv = driv->next) {
 173                         if (!try_module_get(driv->module))
 174                                 continue;
 175                         comedi_report_boards(driv);
 176                         module_put(driv->module);
 177                 }
 178                 return -EIO;
 179         }
 180         if (driv->attach == NULL) {
 181                 /* driver does not support manual configuration */
 182                 dev_warn(dev->class_dev,
 183                          "driver '%s' does not support attach using comedi_config\n",
 184                          driv->driver_name);
 185                 module_put(driv->module);
 186                 return -ENOSYS;
 187         }
 188         /* initialize dev->driver here so
 189          * comedi_error() can be called from attach */
 190         dev->driver = driv;
 191         ret = driv->attach(dev, it);
 192         if (ret < 0) {
 193                 module_put(dev->driver->module);
 194                 __comedi_device_detach(dev);
 195                 return ret;
 196         }
 197         return comedi_device_postconfig(dev);
 198 }
 199
 200 int comedi_driver_register(struct comedi_driver *driver)
 201 {
 202         driver->next = comedi_drivers;
 203         comedi_drivers = driver;
 204
 205         return 0;
 206 }
 207 EXPORT_SYMBOL(comedi_driver_register);
 208
 209 int comedi_driver_unregister(struct comedi_driver *driver)
 210 {
 211         struct comedi_driver *prev;
 212         int i;
 213
 214         /* check for devices using this driver */
 215         for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
 216                 struct comedi_device_file_info *dev_file_info =
 217                     comedi_get_device_file_info(i);
 218                 struct comedi_device *dev;
 219
 220                 if (dev_file_info == NULL)
 221                         continue;
 222                 dev = dev_file_info->device;
 223
 224                 mutex_lock(&dev->mutex);
 225                 if (dev->attached && dev->driver == driver) {
 226                         if (dev->use_count)
 227                                 dev_warn(dev->class_dev,
 228                                          "BUG! detaching device with use_count=%d\n",
 229                                          dev->use_count);
 230                         comedi_device_detach(dev);
 231                 }
 232                 mutex_unlock(&dev->mutex);
 233         }
 234
 235         if (comedi_drivers == driver) {
 236                 comedi_drivers = driver->next;
 237                 return 0;
 238         }
 239
 240         for (prev = comedi_drivers; prev->next; prev = prev->next) {
 241                 if (prev->next == driver) {
 242                         prev->next = driver->next;
 243                         return 0;
 244                 }
 245         }
 246         return -EINVAL;
 247 }
 248 EXPORT_SYMBOL(comedi_driver_unregister);
 249
 250 static int postconfig(struct comedi_device *dev)
 251 {
 252         int i;
 253         struct comedi_subdevice *s;
 254         struct comedi_async *async = NULL;
 255         int ret;
 256
 257         for (i = 0; i < dev->n_subdevices; i++) {
 258                 s = &dev->subdevices[i];
 259
 260                 if (s->type == COMEDI_SUBD_UNUSED)
 261                         continue;
 262
 263                 if (s->len_chanlist == 0)
 264                         s->len_chanlist = 1;
 265
 266                 if (s->do_cmd) {
 267                         unsigned int buf_size;
 268
 269                         BUG_ON((s->subdev_flags & (SDF_CMD_READ |
 270                                                    SDF_CMD_WRITE)) == 0);
 271                         BUG_ON(!s->do_cmdtest);
 272
 273                         async =
 274                             kzalloc(sizeof(struct comedi_async), GFP_KERNEL);
 275                         if (async == NULL) {
 276                                 dev_warn(dev->class_dev,
 277                                          "failed to allocate async struct\n");
 278                                 return -ENOMEM;
 279                         }
 280                         init_waitqueue_head(&async->wait_head);
 281                         async->subdevice = s;
 282                         s->async = async;
 283
 284                         async->max_bufsize =
 285                                 comedi_default_buf_maxsize_kb * 1024;
 286                         buf_size = comedi_default_buf_size_kb * 1024;
 287                         if (buf_size > async->max_bufsize)
 288                                 buf_size = async->max_bufsize;
 289
 290                         async->prealloc_buf = NULL;
 291                         async->prealloc_bufsz = 0;
 292                         if (comedi_buf_alloc(dev, s, buf_size) < 0) {
 293                                 dev_warn(dev->class_dev,
 294                                          "Buffer allocation failed\n");
 295                                 return -ENOMEM;
 296                         }
 297                         if (s->buf_change) {
 298                                 ret = s->buf_change(dev, s, buf_size);
 299                                 if (ret < 0)
 300                                         return ret;
 301                         }
 302                         comedi_alloc_subdevice_minor(dev, s);
 303                 }
 304
 305                 if (!s->range_table && !s->range_table_list)
 306                         s->range_table = &range_unknown;
 307
 308                 if (!s->insn_read && s->insn_bits)
 309                         s->insn_read = insn_rw_emulate_bits;
 310                 if (!s->insn_write && s->insn_bits)
 311                         s->insn_write = insn_rw_emulate_bits;
 312
 313                 if (!s->insn_read)
 314                         s->insn_read = insn_inval;
 315                 if (!s->insn_write)
 316                         s->insn_write = insn_inval;
 317                 if (!s->insn_bits)
 318                         s->insn_bits = insn_inval;
 319                 if (!s->insn_config)
 320                         s->insn_config = insn_inval;
 321
 322                 if (!s->poll)
 323                         s->poll = poll_invalid;
 324         }
 325
 326         return 0;
 327 }
 328
 329 /*
 330  * Generic recognize function for drivers that register their supported
 331  * board names.
 332  *
 333  * 'driv->board_name' points to a 'const char *' member within the
 334  * zeroth element of an array of some private board information
 335  * structure, say 'struct foo_board' containing a member 'const char
 336  * *board_name' that is initialized to point to a board name string that
 337  * is one of the candidates matched against this function's 'name'
 338  * parameter.
 339  *
 340  * 'driv->offset' is the size of the private board information
 341  * structure, say 'sizeof(struct foo_board)', and 'driv->num_names' is
 342  * the length of the array of private board information structures.
 343  *
 344  * If one of the board names in the array of private board information
 345  * structures matches the name supplied to this function, the function
 346  * returns a pointer to the pointer to the board name, otherwise it
 347  * returns NULL.  The return value ends up in the 'board_ptr' member of
 348  * a 'struct comedi_device' that the low-level comedi driver's
 349  * 'attach()' hook can convert to a point to a particular element of its
 350  * array of private board information structures by subtracting the
 351  * offset of the member that points to the board name.  (No subtraction
 352  * is required if the board name pointer is the first member of the
 353  * private board information structure, which is generally the case.)
 354  */
 355 static void *comedi_recognize(struct comedi_driver *driv, const char *name)
 356 {
 357         char **name_ptr = (char **)driv->board_name;
 358         int i;
 359
 360         for (i = 0; i < driv->num_names; i++) {
 361                 if (strcmp(*name_ptr, name) == 0)
 362                         return name_ptr;
 363                 name_ptr = (void *)name_ptr + driv->offset;
 364         }
 365
 366         return NULL;
 367 }
 368
 369 static void comedi_report_boards(struct comedi_driver *driv)
 370 {
 371         unsigned int i;
 372         const char *const *name_ptr;
 373
 374         pr_info("comedi: valid board names for %s driver are:\n",
 375                 driv->driver_name);
 376
 377         name_ptr = driv->board_name;
 378         for (i = 0; i < driv->num_names; i++) {
 379                 pr_info(" %s\n", *name_ptr);
 380                 name_ptr = (const char **)((char *)name_ptr + driv->offset);
 381         }
 382
 383         if (driv->num_names == 0)
 384                 pr_info(" %s\n", driv->driver_name);
 385 }
 386
 387 static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s)
 388 {
 389         return -EINVAL;
 390 }
 391
 392 int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s,
 393                struct comedi_insn *insn, unsigned int *data)
 394 {
 395         return -EINVAL;
 396 }
 397
 398 static int insn_rw_emulate_bits(struct comedi_device *dev,
 399                                 struct comedi_subdevice *s,
 400                                 struct comedi_insn *insn, unsigned int *data)
 401 {
 402         struct comedi_insn new_insn;
 403         int ret;
 404         static const unsigned channels_per_bitfield = 32;
 405
 406         unsigned chan = CR_CHAN(insn->chanspec);
 407         const unsigned base_bitfield_channel =
 408             (chan < channels_per_bitfield) ? 0 : chan;
 409         unsigned int new_data[2];
 410         memset(new_data, 0, sizeof(new_data));
 411         memset(&new_insn, 0, sizeof(new_insn));
 412         new_insn.insn = INSN_BITS;
 413         new_insn.chanspec = base_bitfield_channel;
 414         new_insn.n = 2;
 415         new_insn.subdev = insn->subdev;
 416
 417         if (insn->insn == INSN_WRITE) {
 418                 if (!(s->subdev_flags & SDF_WRITABLE))
 419                         return -EINVAL;
 420                 new_data[0] = 1 << (chan - base_bitfield_channel); /* mask */
 421                 new_data[1] = data[0] ? (1 << (chan - base_bitfield_channel))
 422                               : 0; /* bits */
 423         }
 424
 425         ret = s->insn_bits(dev, s, &new_insn, new_data);
 426         if (ret < 0)
 427                 return ret;
 428
 429         if (insn->insn == INSN_READ)
 430                 data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1;
 431
 432         return 1;
 433 }
 434
 435 int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
 436                      unsigned long new_size)
 437 {
 438         struct comedi_async *async = s->async;
 439
 440         /* Round up new_size to multiple of PAGE_SIZE */
 441         new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
 442
 443         /* if no change is required, do nothing */
 444         if (async->prealloc_buf && async->prealloc_bufsz == new_size)
 445                 return 0;
 446
 447         /*  deallocate old buffer */
 448         if (async->prealloc_buf) {
 449                 vunmap(async->prealloc_buf);
 450                 async->prealloc_buf = NULL;
 451                 async->prealloc_bufsz = 0;
 452         }
 453         if (async->buf_page_list) {
 454                 unsigned i;
 455                 for (i = 0; i < async->n_buf_pages; ++i) {
 456                         if (async->buf_page_list[i].virt_addr) {
 457                                 clear_bit(PG_reserved,
 458                                         &(virt_to_page(async->buf_page_list[i].
 459                                                         virt_addr)->flags));
 460                                 if (s->async_dma_dir != DMA_NONE) {
 461                                         dma_free_coherent(dev->hw_dev,
 462                                                           PAGE_SIZE,
 463                                                           async->
 464                                                           buf_page_list
 465                                                           [i].virt_addr,
 466                                                           async->
 467                                                           buf_page_list
 468                                                           [i].dma_addr);
 469                                 } else {
 470                                         free_page((unsigned long)
 471                                                   async->buf_page_list[i].
 472                                                   virt_addr);
 473                                 }
 474                         }
 475                 }
 476                 vfree(async->buf_page_list);
 477                 async->buf_page_list = NULL;
 478                 async->n_buf_pages = 0;
 479         }
 480         /*  allocate new buffer */
 481         if (new_size) {
 482                 unsigned i = 0;
 483                 unsigned n_pages = new_size >> PAGE_SHIFT;
 484                 struct page **pages = NULL;
 485
 486                 async->buf_page_list =
 487                     vzalloc(sizeof(struct comedi_buf_page) * n_pages);
 488                 if (async->buf_page_list)
 489                         pages = vmalloc(sizeof(struct page *) * n_pages);
 490
 491                 if (pages) {
 492                         for (i = 0; i < n_pages; i++) {
 493                                 if (s->async_dma_dir != DMA_NONE) {
 494                                         async->buf_page_list[i].virt_addr =
 495                                             dma_alloc_coherent(dev->hw_dev,
 496                                                                PAGE_SIZE,
 497                                                                &async->
 498                                                                buf_page_list
 499                                                                [i].dma_addr,
 500                                                                GFP_KERNEL |
 501                                                                __GFP_COMP);
 502                                 } else {
 503                                         async->buf_page_list[i].virt_addr =
 504                                             (void *)
 505                                             get_zeroed_page(GFP_KERNEL);
 506                                 }
 507                                 if (async->buf_page_list[i].virt_addr == NULL)
 508                                         break;
 509
 510                                 set_bit(PG_reserved,
 511                                         &(virt_to_page(async->buf_page_list[i].
 512                                                         virt_addr)->flags));
 513                                 pages[i] = virt_to_page(async->buf_page_list[i].
 514                                                                 virt_addr);
 515                         }
 516                 }
 517                 if (i == n_pages) {
 518                         async->prealloc_buf =
 519 #ifdef PAGE_KERNEL_NOCACHE
 520                             vmap(pages, n_pages, VM_MAP, PAGE_KERNEL_NOCACHE);
 521 #else
 522                             vmap(pages, n_pages, VM_MAP, PAGE_KERNEL);
 523 #endif
 524                 }
 525                 vfree(pages);
 526
 527                 if (async->prealloc_buf == NULL) {
 528                         /* Some allocation failed above. */
 529                         if (async->buf_page_list) {
 530                                 for (i = 0; i < n_pages; i++) {
 531                                         if (async->buf_page_list[i].virt_addr ==
 532                                             NULL) {
 533                                                 break;
 534                                         }
 535                                         clear_bit(PG_reserved,
 536                                                 &(virt_to_page(async->
 537                                                         buf_page_list[i].
 538                                                         virt_addr)->flags));
 539                                         if (s->async_dma_dir != DMA_NONE) {
 540                                                 dma_free_coherent(dev->hw_dev,
 541                                                                   PAGE_SIZE,
 542                                                                   async->
 543                                                                   buf_page_list
 544                                                                   [i].virt_addr,
 545                                                                   async->
 546                                                                   buf_page_list
 547                                                                   [i].dma_addr);
 548                                         } else {
 549                                                 free_page((unsigned long)
 550                                                           async->buf_page_list
 551                                                           [i].virt_addr);
 552                                         }
 553                                 }
 554                                 vfree(async->buf_page_list);
 555                                 async->buf_page_list = NULL;
 556                         }
 557                         return -ENOMEM;
 558                 }
 559                 async->n_buf_pages = n_pages;
 560         }
 561         async->prealloc_bufsz = new_size;
 562
 563         return 0;
 564 }
 565
 566 /* munging is applied to data by core as it passes between user
 567  * and kernel space */
 568 static unsigned int comedi_buf_munge(struct comedi_async *async,
 569                                      unsigned int num_bytes)
 570 {
 571         struct comedi_subdevice *s = async->subdevice;
 572         unsigned int count = 0;
 573         const unsigned num_sample_bytes = bytes_per_sample(s);
 574
 575         if (s->munge == NULL || (async->cmd.flags & CMDF_RAWDATA)) {
 576                 async->munge_count += num_bytes;
 577                 BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
 578                 return num_bytes;
 579         }
 580         /* don't munge partial samples */
 581         num_bytes -= num_bytes % num_sample_bytes;
 582         while (count < num_bytes) {
 583                 int block_size;
 584
 585                 block_size = num_bytes - count;
 586                 if (block_size < 0) {
 587                         dev_warn(s->device->class_dev,
 588                                  "%s: %s: bug! block_size is negative\n",
 589                                  __FILE__, __func__);
 590                         break;
 591                 }
 592                 if ((int)(async->munge_ptr + block_size -
 593                           async->prealloc_bufsz) > 0)
 594                         block_size = async->prealloc_bufsz - async->munge_ptr;
 595
 596                 s->munge(s->device, s, async->prealloc_buf + async->munge_ptr,
 597                          block_size, async->munge_chan);
 598
 599                 smp_wmb();      /* barrier insures data is munged in buffer
 600                                  * before munge_count is incremented */
 601
 602                 async->munge_chan += block_size / num_sample_bytes;
 603                 async->munge_chan %= async->cmd.chanlist_len;
 604                 async->munge_count += block_size;
 605                 async->munge_ptr += block_size;
 606                 async->munge_ptr %= async->prealloc_bufsz;
 607                 count += block_size;
 608         }
 609         BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
 610         return count;
 611 }
 612
 613 unsigned int comedi_buf_write_n_available(struct comedi_async *async)
 614 {
 615         unsigned int free_end;
 616         unsigned int nbytes;
 617
 618         if (async == NULL)
 619                 return 0;
 620
 621         free_end = async->buf_read_count + async->prealloc_bufsz;
 622         nbytes = free_end - async->buf_write_alloc_count;
 623         nbytes -= nbytes % bytes_per_sample(async->subdevice);
 624         /* barrier insures the read of buf_read_count in this
 625            query occurs before any following writes to the buffer which
 626            might be based on the return value from this query.
 627          */
 628         smp_mb();
 629         return nbytes;
 630 }
 631
 632 /* allocates chunk for the writer from free buffer space */
 633 unsigned int comedi_buf_write_alloc(struct comedi_async *async,
 634                                     unsigned int nbytes)
 635 {
 636         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 637
 638         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0)
 639                 nbytes = free_end - async->buf_write_alloc_count;
 640
 641         async->buf_write_alloc_count += nbytes;
 642         /* barrier insures the read of buf_read_count above occurs before
 643            we write data to the write-alloc'ed buffer space */
 644         smp_mb();
 645         return nbytes;
 646 }
 647 EXPORT_SYMBOL(comedi_buf_write_alloc);
 648
 649 /* allocates nothing unless it can completely fulfill the request */
 650 unsigned int comedi_buf_write_alloc_strict(struct comedi_async *async,
 651                                            unsigned int nbytes)
 652 {
 653         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 654
 655         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0)
 656                 nbytes = 0;
 657
 658         async->buf_write_alloc_count += nbytes;
 659         /* barrier insures the read of buf_read_count above occurs before
 660            we write data to the write-alloc'ed buffer space */
 661         smp_mb();
 662         return nbytes;
 663 }
 664
 665 /* transfers a chunk from writer to filled buffer space */
 666 unsigned comedi_buf_write_free(struct comedi_async *async, unsigned int nbytes)
 667 {
 668         if ((int)(async->buf_write_count + nbytes -
 669                   async->buf_write_alloc_count) > 0) {
 670                 dev_info(async->subdevice->device->class_dev,
 671                          "attempted to write-free more bytes than have been write-allocated.\n");
 672                 nbytes = async->buf_write_alloc_count - async->buf_write_count;
 673         }
 674         async->buf_write_count += nbytes;
 675         async->buf_write_ptr += nbytes;
 676         comedi_buf_munge(async, async->buf_write_count - async->munge_count);
 677         if (async->buf_write_ptr >= async->prealloc_bufsz)
 678                 async->buf_write_ptr %= async->prealloc_bufsz;
 679
 680         return nbytes;
 681 }
 682 EXPORT_SYMBOL(comedi_buf_write_free);
 683
 684 /* allocates a chunk for the reader from filled (and munged) buffer space */
 685 unsigned comedi_buf_read_alloc(struct comedi_async *async, unsigned nbytes)
 686 {
 687         if ((int)(async->buf_read_alloc_count + nbytes - async->munge_count) >
 688             0) {
 689                 nbytes = async->munge_count - async->buf_read_alloc_count;
 690         }
 691         async->buf_read_alloc_count += nbytes;
 692         /* barrier insures read of munge_count occurs before we actually read
 693            data out of buffer */
 694         smp_rmb();
 695         return nbytes;
 696 }
 697 EXPORT_SYMBOL(comedi_buf_read_alloc);
 698
 699 /* transfers control of a chunk from reader to free buffer space */
 700 unsigned comedi_buf_read_free(struct comedi_async *async, unsigned int nbytes)
 701 {
 702         /* barrier insures data has been read out of
 703          * buffer before read count is incremented */
 704         smp_mb();
 705         if ((int)(async->buf_read_count + nbytes -
 706                   async->buf_read_alloc_count) > 0) {
 707                 dev_info(async->subdevice->device->class_dev,
 708                          "attempted to read-free more bytes than have been read-allocated.\n");
 709                 nbytes = async->buf_read_alloc_count - async->buf_read_count;
 710         }
 711         async->buf_read_count += nbytes;
 712         async->buf_read_ptr += nbytes;
 713         async->buf_read_ptr %= async->prealloc_bufsz;
 714         return nbytes;
 715 }
 716 EXPORT_SYMBOL(comedi_buf_read_free);
 717
 718 void comedi_buf_memcpy_to(struct comedi_async *async, unsigned int offset,
 719                           const void *data, unsigned int num_bytes)
 720 {
 721         unsigned int write_ptr = async->buf_write_ptr + offset;
 722
 723         if (write_ptr >= async->prealloc_bufsz)
 724                 write_ptr %= async->prealloc_bufsz;
 725
 726         while (num_bytes) {
 727                 unsigned int block_size;
 728
 729                 if (write_ptr + num_bytes > async->prealloc_bufsz)
 730                         block_size = async->prealloc_bufsz - write_ptr;
 731                 else
 732                         block_size = num_bytes;
 733
 734                 memcpy(async->prealloc_buf + write_ptr, data, block_size);
 735
 736                 data += block_size;
 737                 num_bytes -= block_size;
 738
 739                 write_ptr = 0;
 740         }
 741 }
 742 EXPORT_SYMBOL(comedi_buf_memcpy_to);
 743
 744 void comedi_buf_memcpy_from(struct comedi_async *async, unsigned int offset,
 745                             void *dest, unsigned int nbytes)
 746 {
 747         void *src;
 748         unsigned int read_ptr = async->buf_read_ptr + offset;
 749
 750         if (read_ptr >= async->prealloc_bufsz)
 751                 read_ptr %= async->prealloc_bufsz;
 752
 753         while (nbytes) {
 754                 unsigned int block_size;
 755
 756                 src = async->prealloc_buf + read_ptr;
 757
 758                 if (nbytes >= async->prealloc_bufsz - read_ptr)
 759                         block_size = async->prealloc_bufsz - read_ptr;
 760                 else
 761                         block_size = nbytes;
 762
 763                 memcpy(dest, src, block_size);
 764                 nbytes -= block_size;
 765                 dest += block_size;
 766                 read_ptr = 0;
 767         }
 768 }
 769 EXPORT_SYMBOL(comedi_buf_memcpy_from);
 770
 771 unsigned int comedi_buf_read_n_available(struct comedi_async *async)
 772 {
 773         unsigned num_bytes;
 774
 775         if (async == NULL)
 776                 return 0;
 777         num_bytes = async->munge_count - async->buf_read_count;
 778         /* barrier insures the read of munge_count in this
 779            query occurs before any following reads of the buffer which
 780            might be based on the return value from this query.
 781          */
 782         smp_rmb();
 783         return num_bytes;
 784 }
 785 EXPORT_SYMBOL(comedi_buf_read_n_available);
 786
 787 int comedi_buf_get(struct comedi_async *async, short *x)
 788 {
 789         unsigned int n = comedi_buf_read_n_available(async);
 790
 791         if (n < sizeof(short))
 792                 return 0;
 793         comedi_buf_read_alloc(async, sizeof(short));
 794         *x = *(short *)(async->prealloc_buf + async->buf_read_ptr);
 795         comedi_buf_read_free(async, sizeof(short));
 796         return 1;
 797 }
 798 EXPORT_SYMBOL(comedi_buf_get);
 799
 800 int comedi_buf_put(struct comedi_async *async, short x)
 801 {
 802         unsigned int n = comedi_buf_write_alloc_strict(async, sizeof(short));
 803
 804         if (n < sizeof(short)) {
 805                 async->events |= COMEDI_CB_ERROR;
 806                 return 0;
 807         }
 808         *(short *)(async->prealloc_buf + async->buf_write_ptr) = x;
 809         comedi_buf_write_free(async, sizeof(short));
 810         return 1;
 811 }
 812 EXPORT_SYMBOL(comedi_buf_put);
 813
 814 void comedi_reset_async_buf(struct comedi_async *async)
 815 {
 816         async->buf_write_alloc_count = 0;
 817         async->buf_write_count = 0;
 818         async->buf_read_alloc_count = 0;
 819         async->buf_read_count = 0;
 820
 821         async->buf_write_ptr = 0;
 822         async->buf_read_ptr = 0;
 823
 824         async->cur_chan = 0;
 825         async->scan_progress = 0;
 826         async->munge_chan = 0;
 827         async->munge_count = 0;
 828         async->munge_ptr = 0;
 829
 830         async->events = 0;
 831 }
 832
 833 int comedi_auto_config(struct device *hardware_device,
 834                        struct comedi_driver *driver, unsigned long context)
 835 {
 836         int minor;
 837         struct comedi_device_file_info *dev_file_info;
 838         struct comedi_device *comedi_dev;
 839         int ret;
 840
 841         if (!comedi_autoconfig)
 842                 return 0;
 843
 844         if (!driver->auto_attach) {
 845                 dev_warn(hardware_device,
 846                          "BUG! comedi driver '%s' has no auto_attach handler\n",
 847                          driver->driver_name);
 848                 return -EINVAL;
 849         }
 850
 851         minor = comedi_alloc_board_minor(hardware_device);
 852         if (minor < 0)
 853                 return minor;
 854
 855         dev_file_info = comedi_get_device_file_info(minor);
 856         comedi_dev = dev_file_info->device;
 857
 858         mutex_lock(&comedi_dev->mutex);
 859         if (comedi_dev->attached)
 860                 ret = -EBUSY;
 861         else if (!try_module_get(driver->module))
 862                 ret = -EIO;
 863         else {
 864                 comedi_set_hw_dev(comedi_dev, hardware_device);
 865                 comedi_dev->driver = driver;
 866                 ret = driver->auto_attach(comedi_dev, context);
 867                 if (ret < 0) {
 868                         module_put(driver->module);
 869                         __comedi_device_detach(comedi_dev);
 870                 } else {
 871                         ret = comedi_device_postconfig(comedi_dev);
 872                 }
 873         }
 874         mutex_unlock(&comedi_dev->mutex);
 875
 876         if (ret < 0)
 877                 comedi_free_board_minor(minor);
 878         return ret;
 879 }
 880 EXPORT_SYMBOL_GPL(comedi_auto_config);
 881
 882 void comedi_auto_unconfig(struct device *hardware_device)
 883 {
 884         int minor;
 885
 886         if (hardware_device == NULL)
 887                 return;
 888         minor = comedi_find_board_minor(hardware_device);
 889         if (minor < 0)
 890                 return;
 891         BUG_ON(minor >= COMEDI_NUM_BOARD_MINORS);
 892         comedi_free_board_minor(minor);
 893 }
 894 EXPORT_SYMBOL_GPL(comedi_auto_unconfig);
 895
 896 /**
 897  * comedi_pci_enable() - Enable the PCI device and request the regions.
 898  * @pdev: pci_dev struct
 899  * @res_name: name for the requested reqource
 900  */
 901 int comedi_pci_enable(struct pci_dev *pdev, const char *res_name)
 902 {
 903         int rc;
 904
 905         rc = pci_enable_device(pdev);
 906         if (rc < 0)
 907                 return rc;
 908
 909         rc = pci_request_regions(pdev, res_name);
 910         if (rc < 0)
 911                 pci_disable_device(pdev);
 912
 913         return rc;
 914 }
 915 EXPORT_SYMBOL_GPL(comedi_pci_enable);
 916
 917 /**
 918  * comedi_pci_disable() - Release the regions and disable the PCI device.
 919  * @pdev: pci_dev struct
 920  *
 921  * This must be matched with a previous successful call to comedi_pci_enable().
 922  */
 923 void comedi_pci_disable(struct pci_dev *pdev)
 924 {
 925         pci_release_regions(pdev);
 926         pci_disable_device(pdev);
 927 }
 928 EXPORT_SYMBOL_GPL(comedi_pci_disable);
 929
 930 int comedi_pci_driver_register(struct comedi_driver *comedi_driver,
 931                 struct pci_driver *pci_driver)
 932 {
 933         int ret;
 934
 935         ret = comedi_driver_register(comedi_driver);
 936         if (ret < 0)
 937                 return ret;
 938
 939         /* FIXME: Remove this test after auditing all comedi pci drivers */
 940         if (!pci_driver->name)
 941                 pci_driver->name = comedi_driver->driver_name;
 942
 943         ret = pci_register_driver(pci_driver);
 944         if (ret < 0) {
 945                 comedi_driver_unregister(comedi_driver);
 946                 return ret;
 947         }
 948
 949         return 0;
 950 }
 951 EXPORT_SYMBOL_GPL(comedi_pci_driver_register);
 952
 953 void comedi_pci_driver_unregister(struct comedi_driver *comedi_driver,
 954                 struct pci_driver *pci_driver)
 955 {
 956         pci_unregister_driver(pci_driver);
 957         comedi_driver_unregister(comedi_driver);
 958 }
 959 EXPORT_SYMBOL_GPL(comedi_pci_driver_unregister);
 960
 961 #if IS_ENABLED(CONFIG_USB)
 962
 963 int comedi_usb_driver_register(struct comedi_driver *comedi_driver,
 964                 struct usb_driver *usb_driver)
 965 {
 966         int ret;
 967
 968         ret = comedi_driver_register(comedi_driver);
 969         if (ret < 0)
 970                 return ret;
 971
 972         ret = usb_register(usb_driver);
 973         if (ret < 0) {
 974                 comedi_driver_unregister(comedi_driver);
 975                 return ret;
 976         }
 977
 978         return 0;
 979 }
 980 EXPORT_SYMBOL_GPL(comedi_usb_driver_register);
 981
 982 void comedi_usb_driver_unregister(struct comedi_driver *comedi_driver,
 983                 struct usb_driver *usb_driver)
 984 {
 985         usb_deregister(usb_driver);
 986         comedi_driver_unregister(comedi_driver);
 987 }
 988 EXPORT_SYMBOL_GPL(comedi_usb_driver_unregister);
 989
 990 #endif