drivers/staging/comedi/drivers.c

   1 /*
   2     module/drivers.c
   3     functions for manipulating drivers
   4
   5     COMEDI - Linux Control and Measurement Device Interface
   6     Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License as published by
  10     the Free Software Foundation; either version 2 of the License, or
  11     (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License
  19     along with this program; if not, write to the Free Software
  20     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21
  22 */
  23
  24 #define _GNU_SOURCE
  25
  26 #define __NO_VERSION__
  27 #include "comedi_fops.h"
  28 #include <linux/device.h>
  29 #include <linux/module.h>
  30 #include <linux/pci.h>
  31 #include <linux/usb.h>
  32 #include <linux/errno.h>
  33 #include <linux/kernel.h>
  34 #include <linux/sched.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/delay.h>
  37 #include <linux/ioport.h>
  38 #include <linux/mm.h>
  39 #include <linux/slab.h>
  40 #include "comedidev.h"
  41 #include "wrapper.h"
  42 #include <linux/highmem.h>      /* for SuSE brokenness */
  43 #include <linux/vmalloc.h>
  44 #include <linux/cdev.h>
  45 #include <linux/dma-mapping.h>
  46
  47 #include <asm/io.h>
  48 #include <asm/system.h>
  49
  50 static int postconfig(struct comedi_device *dev);
  51 static int insn_rw_emulate_bits(struct comedi_device *dev, 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 int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
  57         unsigned long new_size);
  58
  59 struct comedi_driver *comedi_drivers;
  60
  61 int comedi_modprobe(int minor)
  62 {
  63         return -EINVAL;
  64 }
  65
  66 static void cleanup_device(struct comedi_device *dev)
  67 {
  68         int i;
  69         struct comedi_subdevice *s;
  70
  71         if (dev->subdevices) {
  72                 for (i = 0; i < dev->n_subdevices; i++) {
  73                         s = dev->subdevices + i;
  74                         comedi_free_subdevice_minor(s);
  75                         if (s->async) {
  76                                 comedi_buf_alloc(dev, s, 0);
  77                                 kfree(s->async);
  78                         }
  79                 }
  80                 kfree(dev->subdevices);
  81                 dev->subdevices = NULL;
  82                 dev->n_subdevices = 0;
  83         }
  84         kfree(dev->private);
  85         dev->private = NULL;
  86         dev->driver = 0;
  87         dev->board_name = NULL;
  88         dev->board_ptr = NULL;
  89         dev->iobase = 0;
  90         dev->irq = 0;
  91         dev->read_subdev = NULL;
  92         dev->write_subdev = NULL;
  93         dev->open = NULL;
  94         dev->close = NULL;
  95         comedi_set_hw_dev(dev, NULL);
  96 }
  97
  98 static void __comedi_device_detach(struct comedi_device *dev)
  99 {
 100         dev->attached = 0;
 101         if (dev->driver) {
 102                 dev->driver->detach(dev);
 103         } else {
 104                 printk("BUG: dev->driver=NULL in comedi_device_detach()\n");
 105         }
 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("comedi: failed to increment module count, skipping\n");
 127                         continue;
 128                 }
 129                 if (driv->num_names) {
 130                         dev->board_ptr = comedi_recognize(driv, it->board_name);
 131                         if (dev->board_ptr == NULL) {
 132                                 module_put(driv->module);
 133                                 continue;
 134                         }
 135                 } else {
 136                         if (strcmp(driv->driver_name, it->board_name)) {
 137                                 module_put(driv->module);
 138                                 continue;
 139                         }
 140                 }
 141                 /* initialize dev->driver here so comedi_error() can be called from attach */
 142                 dev->driver = driv;
 143                 ret = driv->attach(dev, it);
 144                 if (ret < 0) {
 145                         module_put(dev->driver->module);
 146                         __comedi_device_detach(dev);
 147                         return ret;
 148                 }
 149                 goto attached;
 150         }
 151
 152         /*  recognize has failed if we get here */
 153         /*  report valid board names before returning error */
 154         for (driv = comedi_drivers; driv; driv = driv->next) {
 155                 if (!try_module_get(driv->module)) {
 156                         printk("comedi: failed to increment module count\n");
 157                         continue;
 158                 }
 159                 comedi_report_boards(driv);
 160                 module_put(driv->module);
 161         }
 162         return -EIO;
 163
 164 attached:
 165         /* do a little post-config cleanup */
 166         ret = postconfig(dev);
 167         module_put(dev->driver->module);
 168         if (ret < 0) {
 169                 __comedi_device_detach(dev);
 170                 return ret;
 171         }
 172
 173         if (!dev->board_name) {
 174                 printk("BUG: dev->board_name=<%p>\n", dev->board_name);
 175                 dev->board_name = "BUG";
 176         }
 177         smp_wmb();
 178         dev->attached = 1;
 179
 180         return 0;
 181 }
 182
 183 int comedi_driver_register(struct comedi_driver *driver)
 184 {
 185         driver->next = comedi_drivers;
 186         comedi_drivers = driver;
 187
 188         return 0;
 189 }
 190
 191 int comedi_driver_unregister(struct comedi_driver *driver)
 192 {
 193         struct comedi_driver *prev;
 194         int i;
 195
 196         /* check for devices using this driver */
 197         for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
 198                 struct comedi_device_file_info *dev_file_info = comedi_get_device_file_info(i);
 199                 struct comedi_device *dev;
 200
 201                 if (dev_file_info == NULL) continue;
 202                 dev = dev_file_info->device;
 203
 204                 mutex_lock(&dev->mutex);
 205                 if (dev->attached && dev->driver == driver) {
 206                         if (dev->use_count)
 207                                 printk("BUG! detaching device with use_count=%d\n", dev->use_count);
 208                         comedi_device_detach(dev);
 209                 }
 210                 mutex_unlock(&dev->mutex);
 211         }
 212
 213         if (comedi_drivers == driver) {
 214                 comedi_drivers = driver->next;
 215                 return 0;
 216         }
 217
 218         for (prev = comedi_drivers; prev->next; prev = prev->next) {
 219                 if (prev->next == driver) {
 220                         prev->next = driver->next;
 221                         return 0;
 222                 }
 223         }
 224         return -EINVAL;
 225 }
 226
 227 static int postconfig(struct comedi_device *dev)
 228 {
 229         int i;
 230         struct comedi_subdevice *s;
 231         struct comedi_async *async = NULL;
 232         int ret;
 233
 234         for (i = 0; i < dev->n_subdevices; i++) {
 235                 s = dev->subdevices + i;
 236
 237                 if (s->type == COMEDI_SUBD_UNUSED)
 238                         continue;
 239
 240                 if (s->len_chanlist == 0)
 241                         s->len_chanlist = 1;
 242
 243                 if (s->do_cmd) {
 244                         BUG_ON((s->subdev_flags & (SDF_CMD_READ |
 245                                 SDF_CMD_WRITE)) == 0);
 246                         BUG_ON(!s->do_cmdtest);
 247
 248                         async = kzalloc(sizeof(struct comedi_async), GFP_KERNEL);
 249                         if (async == NULL) {
 250                                 printk("failed to allocate async struct\n");
 251                                 return -ENOMEM;
 252                         }
 253                         init_waitqueue_head(&async->wait_head);
 254                         async->subdevice = s;
 255                         s->async = async;
 256
 257 #define DEFAULT_BUF_MAXSIZE (64*1024)
 258 #define DEFAULT_BUF_SIZE (64*1024)
 259
 260                         async->max_bufsize = DEFAULT_BUF_MAXSIZE;
 261
 262                         async->prealloc_buf = NULL;
 263                         async->prealloc_bufsz = 0;
 264                         if (comedi_buf_alloc(dev, s, DEFAULT_BUF_SIZE) < 0) {
 265                                 printk("Buffer allocation failed\n");
 266                                 return -ENOMEM;
 267                         }
 268                         if (s->buf_change) {
 269                                 ret = s->buf_change(dev, s, DEFAULT_BUF_SIZE);
 270                                 if (ret < 0)
 271                                         return ret;
 272                         }
 273                         comedi_alloc_subdevice_minor(dev, s);
 274                 }
 275
 276                 if (!s->range_table && !s->range_table_list)
 277                         s->range_table = &range_unknown;
 278
 279                 if (!s->insn_read && s->insn_bits)
 280                         s->insn_read = insn_rw_emulate_bits;
 281                 if (!s->insn_write && s->insn_bits)
 282                         s->insn_write = insn_rw_emulate_bits;
 283
 284                 if (!s->insn_read)
 285                         s->insn_read = insn_inval;
 286                 if (!s->insn_write)
 287                         s->insn_write = insn_inval;
 288                 if (!s->insn_bits)
 289                         s->insn_bits = insn_inval;
 290                 if (!s->insn_config)
 291                         s->insn_config = insn_inval;
 292
 293                 if (!s->poll)
 294                         s->poll = poll_invalid;
 295         }
 296
 297         return 0;
 298 }
 299
 300 /*  generic recognize function for drivers that register their supported board names */
 301 void *comedi_recognize(struct comedi_driver * driv, const char *name)
 302 {
 303         unsigned i;
 304         const char *const *name_ptr = driv->board_name;
 305         for (i = 0; i < driv->num_names; i++) {
 306                 if (strcmp(*name_ptr, name) == 0)
 307                         return (void *)name_ptr;
 308                 name_ptr =
 309                         (const char *const *)((const char *)name_ptr +
 310                         driv->offset);
 311         }
 312
 313         return NULL;
 314 }
 315
 316 void comedi_report_boards(struct comedi_driver *driv)
 317 {
 318         unsigned int i;
 319         const char *const *name_ptr;
 320
 321         printk("comedi: valid board names for %s driver are:\n",
 322                 driv->driver_name);
 323
 324         name_ptr = driv->board_name;
 325         for (i = 0; i < driv->num_names; i++) {
 326                 printk(" %s\n", *name_ptr);
 327                 name_ptr = (const char **)((char *)name_ptr + driv->offset);
 328         }
 329
 330         if (driv->num_names == 0)
 331                 printk(" %s\n", driv->driver_name);
 332 }
 333
 334 static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s)
 335 {
 336         return -EINVAL;
 337 }
 338
 339 int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s,
 340         struct comedi_insn *insn, unsigned int *data)
 341 {
 342         return -EINVAL;
 343 }
 344
 345 static int insn_rw_emulate_bits(struct comedi_device *dev, struct comedi_subdevice *s,
 346         struct comedi_insn *insn, unsigned int *data)
 347 {
 348         struct comedi_insn new_insn;
 349         int ret;
 350         static const unsigned channels_per_bitfield = 32;
 351
 352         unsigned chan = CR_CHAN(insn->chanspec);
 353         const unsigned base_bitfield_channel =
 354                 (chan < channels_per_bitfield) ? 0 : chan;
 355         unsigned int new_data[2];
 356         memset(new_data, 0, sizeof(new_data));
 357         memset(&new_insn, 0, sizeof(new_insn));
 358         new_insn.insn = INSN_BITS;
 359         new_insn.chanspec = base_bitfield_channel;
 360         new_insn.n = 2;
 361         new_insn.data = new_data;
 362         new_insn.subdev = insn->subdev;
 363
 364         if (insn->insn == INSN_WRITE) {
 365                 if (!(s->subdev_flags & SDF_WRITABLE))
 366                         return -EINVAL;
 367                 new_data[0] = 1 << (chan - base_bitfield_channel);      /* mask */
 368                 new_data[1] = data[0] ? (1 << (chan - base_bitfield_channel)) : 0;      /* bits */
 369         }
 370
 371         ret = s->insn_bits(dev, s, &new_insn, new_data);
 372         if (ret < 0)
 373                 return ret;
 374
 375         if (insn->insn == INSN_READ) {
 376                 data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1;
 377         }
 378
 379         return 1;
 380 }
 381
 382 static inline unsigned long uvirt_to_kva(pgd_t *pgd, unsigned long adr)
 383 {
 384         unsigned long ret = 0UL;
 385         pmd_t *pmd;
 386         pte_t *ptep, pte;
 387         pud_t *pud;
 388
 389         if (!pgd_none(*pgd)) {
 390                 pud = pud_offset(pgd, adr);
 391                 pmd = pmd_offset(pud, adr);
 392                 if (!pmd_none(*pmd)) {
 393                         ptep = pte_offset_kernel(pmd, adr);
 394                         pte = *ptep;
 395                         if (pte_present(pte)) {
 396                                 ret = (unsigned long)
 397                                         page_address(pte_page(pte));
 398                                 ret |= (adr & (PAGE_SIZE - 1));
 399                         }
 400                 }
 401         }
 402         return ret;
 403 }
 404
 405 static inline unsigned long kvirt_to_kva(unsigned long adr)
 406 {
 407         unsigned long va, kva;
 408
 409         va = adr;
 410         kva = uvirt_to_kva(pgd_offset_k(va), va);
 411
 412         return kva;
 413 }
 414
 415 int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
 416         unsigned long new_size)
 417 {
 418         struct comedi_async *async = s->async;
 419
 420         /* Round up new_size to multiple of PAGE_SIZE */
 421         new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
 422
 423         /* if no change is required, do nothing */
 424         if (async->prealloc_buf && async->prealloc_bufsz == new_size) {
 425                 return 0;
 426         }
 427         /*  deallocate old buffer */
 428         if (async->prealloc_buf) {
 429                 vunmap(async->prealloc_buf);
 430                 async->prealloc_buf = NULL;
 431                 async->prealloc_bufsz = 0;
 432         }
 433         if (async->buf_page_list) {
 434                 unsigned i;
 435                 for (i = 0; i < async->n_buf_pages; ++i) {
 436                         if (async->buf_page_list[i].virt_addr) {
 437                                 mem_map_unreserve(virt_to_page(async->
 438                                                 buf_page_list[i].virt_addr));
 439                                 if (s->async_dma_dir != DMA_NONE) {
 440                                         dma_free_coherent(dev->hw_dev,
 441                                                 PAGE_SIZE,
 442                                                 async->buf_page_list[i].
 443                                                 virt_addr,
 444                                                 async->buf_page_list[i].
 445                                                 dma_addr);
 446                                 } else {
 447                                         free_page((unsigned long)async->
 448                                                 buf_page_list[i].virt_addr);
 449                                 }
 450                         }
 451                 }
 452                 vfree(async->buf_page_list);
 453                 async->buf_page_list = NULL;
 454                 async->n_buf_pages = 0;
 455         }
 456         /*  allocate new buffer */
 457         if (new_size) {
 458                 unsigned i = 0;
 459                 unsigned n_pages = new_size >> PAGE_SHIFT;
 460                 struct page **pages = NULL;
 461
 462                 async->buf_page_list =
 463                         vmalloc(sizeof(struct comedi_buf_page) * n_pages);
 464                 if (async->buf_page_list) {
 465                         memset(async->buf_page_list, 0,
 466                                 sizeof(struct comedi_buf_page) * n_pages);
 467                         pages = vmalloc(sizeof(struct page *) * n_pages);
 468                 }
 469                 if (pages) {
 470                         for (i = 0; i < n_pages; i++) {
 471                                 if (s->async_dma_dir != DMA_NONE) {
 472                                         async->buf_page_list[i].virt_addr =
 473                                                 dma_alloc_coherent(dev->hw_dev,
 474                                                 PAGE_SIZE,
 475                                                 &async->buf_page_list[i].
 476                                                 dma_addr,
 477                                                 GFP_KERNEL | __GFP_COMP);
 478                                 } else {
 479                                         async->buf_page_list[i].virt_addr =
 480                                                 (void *)
 481                                                 get_zeroed_page(GFP_KERNEL);
 482                                 }
 483                                 if (async->buf_page_list[i].virt_addr == NULL) {
 484                                         break;
 485                                 }
 486                                 mem_map_reserve(virt_to_page(async->
 487                                                 buf_page_list[i].virt_addr));
 488                                 pages[i] =
 489                                         virt_to_page(async->buf_page_list[i].
 490                                         virt_addr);
 491                         }
 492                 }
 493                 if (i == n_pages) {
 494                         async->prealloc_buf =
 495                                 vmap(pages, n_pages, VM_MAP,
 496                                 PAGE_KERNEL_NOCACHE);
 497                 }
 498                 if (pages) {
 499                         vfree(pages);
 500                 }
 501                 if (async->prealloc_buf == NULL) {
 502                         /* Some allocation failed above. */
 503                         if (async->buf_page_list) {
 504                                 for (i = 0; i < n_pages; i++) {
 505                                         if (async->buf_page_list[i].virt_addr ==
 506                                                 NULL) {
 507                                                 break;
 508                                         }
 509                                         mem_map_unreserve(virt_to_page(async->
 510                                                         buf_page_list[i].
 511                                                         virt_addr));
 512                                         if (s->async_dma_dir != DMA_NONE) {
 513                                                 dma_free_coherent(dev->hw_dev,
 514                                                         PAGE_SIZE,
 515                                                         async->buf_page_list[i].
 516                                                         virt_addr,
 517                                                         async->buf_page_list[i].
 518                                                         dma_addr);
 519                                         } else {
 520                                                 free_page((unsigned long)async->
 521                                                         buf_page_list[i].
 522                                                         virt_addr);
 523                                         }
 524                                 }
 525                                 vfree(async->buf_page_list);
 526                                 async->buf_page_list = NULL;
 527                         }
 528                         return -ENOMEM;
 529                 }
 530                 async->n_buf_pages = n_pages;
 531         }
 532         async->prealloc_bufsz = new_size;
 533
 534         return 0;
 535 }
 536
 537 /* munging is applied to data by core as it passes between user
 538  * and kernel space */
 539 unsigned int comedi_buf_munge(struct comedi_async *async, unsigned int num_bytes)
 540 {
 541         struct comedi_subdevice *s = async->subdevice;
 542         unsigned int count = 0;
 543         const unsigned num_sample_bytes = bytes_per_sample(s);
 544
 545         if (s->munge == NULL || (async->cmd.flags & CMDF_RAWDATA)) {
 546                 async->munge_count += num_bytes;
 547                 BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
 548                 return num_bytes;
 549         }
 550         /* don't munge partial samples */
 551         num_bytes -= num_bytes % num_sample_bytes;
 552         while (count < num_bytes) {
 553                 int block_size;
 554
 555                 block_size = num_bytes - count;
 556                 if (block_size < 0) {
 557                         printk("%s: %s: bug! block_size is negative\n",
 558                                 __FILE__, __func__);
 559                         break;
 560                 }
 561                 if ((int)(async->munge_ptr + block_size -
 562                                 async->prealloc_bufsz) > 0)
 563                         block_size = async->prealloc_bufsz - async->munge_ptr;
 564
 565                 s->munge(s->device, s, async->prealloc_buf + async->munge_ptr,
 566                         block_size, async->munge_chan);
 567
 568                 smp_wmb();      /* barrier insures data is munged in buffer before munge_count is incremented */
 569
 570                 async->munge_chan += block_size / num_sample_bytes;
 571                 async->munge_chan %= async->cmd.chanlist_len;
 572                 async->munge_count += block_size;
 573                 async->munge_ptr += block_size;
 574                 async->munge_ptr %= async->prealloc_bufsz;
 575                 count += block_size;
 576         }
 577         BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
 578         return count;
 579 }
 580
 581 unsigned int comedi_buf_write_n_available(struct comedi_async *async)
 582 {
 583         unsigned int free_end;
 584         unsigned int nbytes;
 585
 586         if (async == NULL)
 587                 return 0;
 588
 589         free_end = async->buf_read_count + async->prealloc_bufsz;
 590         nbytes = free_end - async->buf_write_alloc_count;
 591         nbytes -= nbytes % bytes_per_sample(async->subdevice);
 592         /* barrier insures the read of buf_read_count in this
 593            query occurs before any following writes to the buffer which
 594            might be based on the return value from this query.
 595          */
 596         smp_mb();
 597         return nbytes;
 598 }
 599
 600 /* allocates chunk for the writer from free buffer space */
 601 unsigned int comedi_buf_write_alloc(struct comedi_async *async, unsigned int nbytes)
 602 {
 603         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 604
 605         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0) {
 606                 nbytes = free_end - async->buf_write_alloc_count;
 607         }
 608         async->buf_write_alloc_count += nbytes;
 609         /* barrier insures the read of buf_read_count above occurs before
 610            we write data to the write-alloc'ed buffer space */
 611         smp_mb();
 612         return nbytes;
 613 }
 614
 615 /* allocates nothing unless it can completely fulfill the request */
 616 unsigned int comedi_buf_write_alloc_strict(struct comedi_async *async,
 617         unsigned int nbytes)
 618 {
 619         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 620
 621         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0) {
 622                 nbytes = 0;
 623         }
 624         async->buf_write_alloc_count += nbytes;
 625         /* barrier insures the read of buf_read_count above occurs before
 626            we write data to the write-alloc'ed buffer space */
 627         smp_mb();
 628         return nbytes;
 629 }
 630
 631 /* transfers a chunk from writer to filled buffer space */
 632 unsigned comedi_buf_write_free(struct comedi_async *async, unsigned int nbytes)
 633 {
 634         if ((int)(async->buf_write_count + nbytes -
 635                         async->buf_write_alloc_count) > 0) {
 636                 printk("comedi: attempted to write-free more bytes than have been write-allocated.\n");
 637                 nbytes = async->buf_write_alloc_count - async->buf_write_count;
 638         }
 639         async->buf_write_count += nbytes;
 640         async->buf_write_ptr += nbytes;
 641         comedi_buf_munge(async, async->buf_write_count - async->munge_count);
 642         if (async->buf_write_ptr >= async->prealloc_bufsz) {
 643                 async->buf_write_ptr %= async->prealloc_bufsz;
 644         }
 645         return nbytes;
 646 }
 647
 648 /* allocates a chunk for the reader from filled (and munged) buffer space */
 649 unsigned comedi_buf_read_alloc(struct comedi_async *async, unsigned nbytes)
 650 {
 651         if ((int)(async->buf_read_alloc_count + nbytes - async->munge_count) >
 652                 0) {
 653                 nbytes = async->munge_count - async->buf_read_alloc_count;
 654         }
 655         async->buf_read_alloc_count += nbytes;
 656         /* barrier insures read of munge_count occurs before we actually read
 657            data out of buffer */
 658         smp_rmb();
 659         return nbytes;
 660 }
 661
 662 /* transfers control of a chunk from reader to free buffer space */
 663 unsigned comedi_buf_read_free(struct comedi_async *async, unsigned int nbytes)
 664 {
 665         /*  barrier insures data has been read out of buffer before read count is incremented */
 666         smp_mb();
 667         if ((int)(async->buf_read_count + nbytes -
 668                         async->buf_read_alloc_count) > 0) {
 669                 printk("comedi: attempted to read-free more bytes than have been read-allocated.\n");
 670                 nbytes = async->buf_read_alloc_count - async->buf_read_count;
 671         }
 672         async->buf_read_count += nbytes;
 673         async->buf_read_ptr += nbytes;
 674         async->buf_read_ptr %= async->prealloc_bufsz;
 675         return nbytes;
 676 }
 677
 678 void comedi_buf_memcpy_to(struct comedi_async *async, unsigned int offset,
 679         const void *data, unsigned int num_bytes)
 680 {
 681         unsigned int write_ptr = async->buf_write_ptr + offset;
 682
 683         if (write_ptr >= async->prealloc_bufsz)
 684                 write_ptr %= async->prealloc_bufsz;
 685
 686         while (num_bytes) {
 687                 unsigned int block_size;
 688
 689                 if (write_ptr + num_bytes > async->prealloc_bufsz)
 690                         block_size = async->prealloc_bufsz - write_ptr;
 691                 else
 692                         block_size = num_bytes;
 693
 694                 memcpy(async->prealloc_buf + write_ptr, data, block_size);
 695
 696                 data += block_size;
 697                 num_bytes -= block_size;
 698
 699                 write_ptr = 0;
 700         }
 701 }
 702
 703 void comedi_buf_memcpy_from(struct comedi_async *async, unsigned int offset,
 704         void *dest, unsigned int nbytes)
 705 {
 706         void *src;
 707         unsigned int read_ptr = async->buf_read_ptr + offset;
 708
 709         if (read_ptr >= async->prealloc_bufsz)
 710                 read_ptr %= async->prealloc_bufsz;
 711
 712         while (nbytes) {
 713                 unsigned int block_size;
 714
 715                 src = async->prealloc_buf + read_ptr;
 716
 717                 if (nbytes >= async->prealloc_bufsz - read_ptr)
 718                         block_size = async->prealloc_bufsz - read_ptr;
 719                 else
 720                         block_size = nbytes;
 721
 722                 memcpy(dest, src, block_size);
 723                 nbytes -= block_size;
 724                 dest += block_size;
 725                 read_ptr = 0;
 726         }
 727 }
 728
 729 unsigned int comedi_buf_read_n_available(struct comedi_async *async)
 730 {
 731         unsigned num_bytes;
 732
 733         if (async == NULL)
 734                 return 0;
 735         num_bytes = async->munge_count - async->buf_read_count;
 736         /* barrier insures the read of munge_count in this
 737            query occurs before any following reads of the buffer which
 738            might be based on the return value from this query.
 739          */
 740         smp_rmb();
 741         return num_bytes;
 742 }
 743
 744 int comedi_buf_get(struct comedi_async *async, short *x)
 745 {
 746         unsigned int n = comedi_buf_read_n_available(async);
 747
 748         if (n < sizeof(short))
 749                 return 0;
 750         comedi_buf_read_alloc(async, sizeof(short));
 751         *x = *(short *) (async->prealloc_buf + async->buf_read_ptr);
 752         comedi_buf_read_free(async, sizeof(short));
 753         return 1;
 754 }
 755
 756 int comedi_buf_put(struct comedi_async *async, short x)
 757 {
 758         unsigned int n = comedi_buf_write_alloc_strict(async, sizeof(short));
 759
 760         if (n < sizeof(short)) {
 761                 async->events |= COMEDI_CB_ERROR;
 762                 return 0;
 763         }
 764         *(short *) (async->prealloc_buf + async->buf_write_ptr) = x;
 765         comedi_buf_write_free(async, sizeof(short));
 766         return 1;
 767 }
 768
 769 void comedi_reset_async_buf(struct comedi_async *async)
 770 {
 771         async->buf_write_alloc_count = 0;
 772         async->buf_write_count = 0;
 773         async->buf_read_alloc_count = 0;
 774         async->buf_read_count = 0;
 775
 776         async->buf_write_ptr = 0;
 777         async->buf_read_ptr = 0;
 778
 779         async->cur_chan = 0;
 780         async->scan_progress = 0;
 781         async->munge_chan = 0;
 782         async->munge_count = 0;
 783         async->munge_ptr = 0;
 784
 785         async->events = 0;
 786 }
 787
 788 int comedi_auto_config(struct device *hardware_device, const char *board_name, const int *options, unsigned num_options)
 789 {
 790         struct comedi_devconfig it;
 791         int minor;
 792         struct comedi_device_file_info *dev_file_info;
 793         int retval;
 794         unsigned *private_data = NULL;
 795
 796         if (!comedi_autoconfig) {
 797                 dev_set_drvdata(hardware_device, NULL);
 798                 return 0;
 799         }
 800
 801         minor = comedi_alloc_board_minor(hardware_device);
 802         if (minor < 0) return minor;
 803
 804         private_data = kmalloc(sizeof(unsigned), GFP_KERNEL);
 805         if (private_data == NULL) {
 806                 retval = -ENOMEM;
 807                 goto cleanup;
 808         }
 809         *private_data = minor;
 810         dev_set_drvdata(hardware_device, private_data);
 811
 812         dev_file_info = comedi_get_device_file_info(minor);
 813
 814         memset(&it, 0, sizeof(it));
 815         strncpy(it.board_name, board_name, COMEDI_NAMELEN);
 816         it.board_name[COMEDI_NAMELEN - 1] = '\0';
 817         BUG_ON(num_options > COMEDI_NDEVCONFOPTS);
 818         memcpy(it.options, options, num_options * sizeof(int));
 819
 820         mutex_lock(&dev_file_info->device->mutex);
 821         retval = comedi_device_attach(dev_file_info->device, &it);
 822         mutex_unlock(&dev_file_info->device->mutex);
 823
 824 cleanup:
 825         if (retval < 0)
 826         {
 827                 kfree(private_data);
 828                 comedi_free_board_minor(minor);
 829         }
 830         return retval;
 831 }
 832
 833 void comedi_auto_unconfig(struct device *hardware_device)
 834 {
 835         unsigned *minor = (unsigned *)dev_get_drvdata(hardware_device);
 836         if (minor == NULL) return;
 837
 838         BUG_ON(*minor >= COMEDI_NUM_BOARD_MINORS);
 839
 840         comedi_free_board_minor(*minor);
 841         dev_set_drvdata(hardware_device, NULL);
 842         kfree(minor);
 843 }
 844
 845 int comedi_pci_auto_config(struct pci_dev *pcidev, const char *board_name)
 846 {
 847         int options[2];
 848
 849         /*  pci bus */
 850         options[0] = pcidev->bus->number;
 851         /*  pci slot */
 852         options[1] = PCI_SLOT(pcidev->devfn);
 853
 854         return comedi_auto_config(&pcidev->dev, board_name,
 855                                   options, ARRAY_SIZE(options));
 856 }
 857
 858 void comedi_pci_auto_unconfig(struct pci_dev *pcidev)
 859 {
 860         comedi_auto_unconfig(&pcidev->dev);
 861 }
 862
 863 int comedi_usb_auto_config(struct usb_device *usbdev,
 864         const char *board_name)
 865 {
 866         BUG_ON(usbdev == NULL);
 867         return comedi_auto_config(&usbdev->dev, board_name, NULL, 0);
 868 }
 869
 870 void comedi_usb_auto_unconfig(struct usb_device *usbdev)
 871 {
 872         BUG_ON(usbdev == NULL);
 873         comedi_auto_unconfig(&usbdev->dev);
 874 }