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(comedi_device * dev);
  51 static int insn_rw_emulate_bits(comedi_device * dev, comedi_subdevice * s,
  52         comedi_insn * insn, lsampl_t * data);
  53 static void *comedi_recognize(comedi_driver * driv, const char *name);
  54 static void comedi_report_boards(comedi_driver * driv);
  55 static int poll_invalid(comedi_device * dev, comedi_subdevice * s);
  56 int comedi_buf_alloc(comedi_device * dev, comedi_subdevice * s,
  57         unsigned long new_size);
  58
  59 comedi_driver *comedi_drivers;
  60
  61 int comedi_modprobe(int minor)
  62 {
  63         return -EINVAL;
  64 }
  65
  66 static void cleanup_device(comedi_device * dev)
  67 {
  68         int i;
  69         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         if (dev->private) {
  85                 kfree(dev->private);
  86                 dev->private = NULL;
  87         }
  88         dev->driver = 0;
  89         dev->board_name = NULL;
  90         dev->board_ptr = NULL;
  91         dev->iobase = 0;
  92         dev->irq = 0;
  93         dev->read_subdev = NULL;
  94         dev->write_subdev = NULL;
  95         dev->open = NULL;
  96         dev->close = NULL;
  97         comedi_set_hw_dev(dev, NULL);
  98 }
  99
 100 static void __comedi_device_detach(comedi_device * dev)
 101 {
 102         dev->attached = 0;
 103         if (dev->driver) {
 104                 dev->driver->detach(dev);
 105         } else {
 106                 printk("BUG: dev->driver=NULL in comedi_device_detach()\n");
 107         }
 108         cleanup_device(dev);
 109 }
 110
 111 void comedi_device_detach(comedi_device * dev)
 112 {
 113         if (!dev->attached)
 114                 return;
 115         __comedi_device_detach(dev);
 116 }
 117
 118 int comedi_device_attach(comedi_device * dev, comedi_devconfig * it)
 119 {
 120         comedi_driver *driv;
 121         int ret;
 122
 123         if (dev->attached)
 124                 return -EBUSY;
 125
 126         for (driv = comedi_drivers; driv; driv = driv->next) {
 127                 if (!try_module_get(driv->module)) {
 128                         printk("comedi: failed to increment module count, skipping\n");
 129                         continue;
 130                 }
 131                 if (driv->num_names) {
 132                         dev->board_ptr = comedi_recognize(driv, it->board_name);
 133                         if (dev->board_ptr == NULL) {
 134                                 module_put(driv->module);
 135                                 continue;
 136                         }
 137                 } else {
 138                         if (strcmp(driv->driver_name, it->board_name)) {
 139                                 module_put(driv->module);
 140                                 continue;
 141                         }
 142                 }
 143                 /* initialize dev->driver here so comedi_error() can be called from attach */
 144                 dev->driver = driv;
 145                 ret = driv->attach(dev, it);
 146                 if (ret < 0) {
 147                         module_put(dev->driver->module);
 148                         __comedi_device_detach(dev);
 149                         return ret;
 150                 }
 151                 goto attached;
 152         }
 153
 154         /*  recognize has failed if we get here */
 155         /*  report valid board names before returning error */
 156         for (driv = comedi_drivers; driv; driv = driv->next) {
 157                 if (!try_module_get(driv->module)) {
 158                         printk("comedi: failed to increment module count\n");
 159                         continue;
 160                 }
 161                 comedi_report_boards(driv);
 162                 module_put(driv->module);
 163         }
 164         return -EIO;
 165
 166 attached:
 167         /* do a little post-config cleanup */
 168         ret = postconfig(dev);
 169         module_put(dev->driver->module);
 170         if (ret < 0) {
 171                 __comedi_device_detach(dev);
 172                 return ret;
 173         }
 174
 175         if (!dev->board_name) {
 176                 printk("BUG: dev->board_name=<%p>\n", dev->board_name);
 177                 dev->board_name = "BUG";
 178         }
 179         smp_wmb();
 180         dev->attached = 1;
 181
 182         return 0;
 183 }
 184
 185 int comedi_driver_register(comedi_driver * driver)
 186 {
 187         driver->next = comedi_drivers;
 188         comedi_drivers = driver;
 189
 190         return 0;
 191 }
 192
 193 int comedi_driver_unregister(comedi_driver * driver)
 194 {
 195         comedi_driver *prev;
 196         int i;
 197
 198         /* check for devices using this driver */
 199         for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
 200                 struct comedi_device_file_info *dev_file_info = comedi_get_device_file_info(i);
 201                 comedi_device *dev;
 202
 203                 if(dev_file_info == NULL) continue;
 204                 dev = dev_file_info->device;
 205
 206                 mutex_lock(&dev->mutex);
 207                 if (dev->attached && dev->driver == driver) {
 208                         if (dev->use_count)
 209                                 printk("BUG! detaching device with use_count=%d\n", dev->use_count);
 210                         comedi_device_detach(dev);
 211                 }
 212                 mutex_unlock(&dev->mutex);
 213         }
 214
 215         if (comedi_drivers == driver) {
 216                 comedi_drivers = driver->next;
 217                 return 0;
 218         }
 219
 220         for (prev = comedi_drivers; prev->next; prev = prev->next) {
 221                 if (prev->next == driver) {
 222                         prev->next = driver->next;
 223                         return 0;
 224                 }
 225         }
 226         return -EINVAL;
 227 }
 228
 229 static int postconfig(comedi_device * dev)
 230 {
 231         int i;
 232         comedi_subdevice *s;
 233         comedi_async *async = NULL;
 234         int ret;
 235
 236         for (i = 0; i < dev->n_subdevices; i++) {
 237                 s = dev->subdevices + i;
 238
 239                 if (s->type == COMEDI_SUBD_UNUSED)
 240                         continue;
 241
 242                 if (s->len_chanlist == 0)
 243                         s->len_chanlist = 1;
 244
 245                 if (s->do_cmd) {
 246                         BUG_ON((s->subdev_flags & (SDF_CMD_READ |
 247                                 SDF_CMD_WRITE)) == 0);
 248                         BUG_ON(!s->do_cmdtest);
 249
 250                         async = kzalloc(sizeof(comedi_async), GFP_KERNEL);
 251                         if (async == NULL) {
 252                                 printk("failed to allocate async struct\n");
 253                                 return -ENOMEM;
 254                         }
 255                         init_waitqueue_head(&async->wait_head);
 256                         async->subdevice = s;
 257                         s->async = async;
 258
 259 #define DEFAULT_BUF_MAXSIZE (64*1024)
 260 #define DEFAULT_BUF_SIZE (64*1024)
 261
 262                         async->max_bufsize = DEFAULT_BUF_MAXSIZE;
 263
 264                         async->prealloc_buf = NULL;
 265                         async->prealloc_bufsz = 0;
 266                         if (comedi_buf_alloc(dev, s, DEFAULT_BUF_SIZE) < 0) {
 267                                 printk("Buffer allocation failed\n");
 268                                 return -ENOMEM;
 269                         }
 270                         if (s->buf_change) {
 271                                 ret = s->buf_change(dev, s, DEFAULT_BUF_SIZE);
 272                                 if (ret < 0)
 273                                         return ret;
 274                         }
 275                         comedi_alloc_subdevice_minor(dev, s);
 276                 }
 277
 278                 if (!s->range_table && !s->range_table_list)
 279                         s->range_table = &range_unknown;
 280
 281                 if (!s->insn_read && s->insn_bits)
 282                         s->insn_read = insn_rw_emulate_bits;
 283                 if (!s->insn_write && s->insn_bits)
 284                         s->insn_write = insn_rw_emulate_bits;
 285
 286                 if (!s->insn_read)
 287                         s->insn_read = insn_inval;
 288                 if (!s->insn_write)
 289                         s->insn_write = insn_inval;
 290                 if (!s->insn_bits)
 291                         s->insn_bits = insn_inval;
 292                 if (!s->insn_config)
 293                         s->insn_config = insn_inval;
 294
 295                 if (!s->poll)
 296                         s->poll = poll_invalid;
 297         }
 298
 299         return 0;
 300 }
 301
 302 /*  generic recognize function for drivers that register their supported board names */
 303 void *comedi_recognize(comedi_driver * driv, const char *name)
 304 {
 305         unsigned i;
 306         const char *const *name_ptr = driv->board_name;
 307         for (i = 0; i < driv->num_names; i++) {
 308                 if (strcmp(*name_ptr, name) == 0)
 309                         return (void *)name_ptr;
 310                 name_ptr =
 311                         (const char *const *)((const char *)name_ptr +
 312                         driv->offset);
 313         }
 314
 315         return NULL;
 316 }
 317
 318 void comedi_report_boards(comedi_driver * driv)
 319 {
 320         unsigned int i;
 321         const char *const *name_ptr;
 322
 323         printk("comedi: valid board names for %s driver are:\n",
 324                 driv->driver_name);
 325
 326         name_ptr = driv->board_name;
 327         for (i = 0; i < driv->num_names; i++) {
 328                 printk(" %s\n", *name_ptr);
 329                 name_ptr = (const char **)((char *)name_ptr + driv->offset);
 330         }
 331
 332         if (driv->num_names == 0)
 333                 printk(" %s\n", driv->driver_name);
 334 }
 335
 336 static int poll_invalid(comedi_device * dev, comedi_subdevice * s)
 337 {
 338         return -EINVAL;
 339 }
 340
 341 int insn_inval(comedi_device * dev, comedi_subdevice * s,
 342         comedi_insn * insn, lsampl_t * data)
 343 {
 344         return -EINVAL;
 345 }
 346
 347 static int insn_rw_emulate_bits(comedi_device * dev, comedi_subdevice * s,
 348         comedi_insn * insn, lsampl_t * data)
 349 {
 350         comedi_insn new_insn;
 351         int ret;
 352         static const unsigned channels_per_bitfield = 32;
 353
 354         unsigned chan = CR_CHAN(insn->chanspec);
 355         const unsigned base_bitfield_channel =
 356                 (chan < channels_per_bitfield) ? 0 : chan;
 357         lsampl_t new_data[2];
 358         memset(new_data, 0, sizeof(new_data));
 359         memset(&new_insn, 0, sizeof(new_insn));
 360         new_insn.insn = INSN_BITS;
 361         new_insn.chanspec = base_bitfield_channel;
 362         new_insn.n = 2;
 363         new_insn.data = new_data;
 364         new_insn.subdev = insn->subdev;
 365
 366         if (insn->insn == INSN_WRITE) {
 367                 if (!(s->subdev_flags & SDF_WRITABLE))
 368                         return -EINVAL;
 369                 new_data[0] = 1 << (chan - base_bitfield_channel);      /* mask */
 370                 new_data[1] = data[0] ? (1 << (chan - base_bitfield_channel)) : 0;      /* bits */
 371         }
 372
 373         ret = s->insn_bits(dev, s, &new_insn, new_data);
 374         if (ret < 0)
 375                 return ret;
 376
 377         if (insn->insn == INSN_READ) {
 378                 data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1;
 379         }
 380
 381         return 1;
 382 }
 383
 384 static inline unsigned long uvirt_to_kva(pgd_t * pgd, unsigned long adr)
 385 {
 386         unsigned long ret = 0UL;
 387         pmd_t *pmd;
 388         pte_t *ptep, pte;
 389         pud_t *pud;
 390
 391         if (!pgd_none(*pgd)) {
 392                 pud = pud_offset(pgd, adr);
 393                 pmd = pmd_offset(pud, adr);
 394                 if (!pmd_none(*pmd)) {
 395                         ptep = pte_offset_kernel(pmd, adr);
 396                         pte = *ptep;
 397                         if (pte_present(pte)) {
 398                                 ret = (unsigned long)
 399                                         page_address(pte_page(pte));
 400                                 ret |= (adr & (PAGE_SIZE - 1));
 401                         }
 402                 }
 403         }
 404         return ret;
 405 }
 406
 407 static inline unsigned long kvirt_to_kva(unsigned long adr)
 408 {
 409         unsigned long va, kva;
 410
 411         va = adr;
 412         kva = uvirt_to_kva(pgd_offset_k(va), va);
 413
 414         return kva;
 415 }
 416
 417 int comedi_buf_alloc(comedi_device * dev, comedi_subdevice * s,
 418         unsigned long new_size)
 419 {
 420         comedi_async *async = s->async;
 421
 422         /* Round up new_size to multiple of PAGE_SIZE */
 423         new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
 424
 425         /* if no change is required, do nothing */
 426         if (async->prealloc_buf && async->prealloc_bufsz == new_size) {
 427                 return 0;
 428         }
 429         /*  deallocate old buffer */
 430         if (async->prealloc_buf) {
 431                 vunmap(async->prealloc_buf);
 432                 async->prealloc_buf = NULL;
 433                 async->prealloc_bufsz = 0;
 434         }
 435         if (async->buf_page_list) {
 436                 unsigned i;
 437                 for (i = 0; i < async->n_buf_pages; ++i) {
 438                         if (async->buf_page_list[i].virt_addr) {
 439                                 mem_map_unreserve(virt_to_page(async->
 440                                                 buf_page_list[i].virt_addr));
 441                                 if (s->async_dma_dir != DMA_NONE) {
 442                                         dma_free_coherent(dev->hw_dev,
 443                                                 PAGE_SIZE,
 444                                                 async->buf_page_list[i].
 445                                                 virt_addr,
 446                                                 async->buf_page_list[i].
 447                                                 dma_addr);
 448                                 } else {
 449                                         free_page((unsigned long)async->
 450                                                 buf_page_list[i].virt_addr);
 451                                 }
 452                         }
 453                 }
 454                 vfree(async->buf_page_list);
 455                 async->buf_page_list = NULL;
 456                 async->n_buf_pages = 0;
 457         }
 458         /*  allocate new buffer */
 459         if (new_size) {
 460                 unsigned i = 0;
 461                 unsigned n_pages = new_size >> PAGE_SHIFT;
 462                 struct page **pages = NULL;
 463
 464                 async->buf_page_list =
 465                         vmalloc(sizeof(struct comedi_buf_page) * n_pages);
 466                 if (async->buf_page_list) {
 467                         memset(async->buf_page_list, 0,
 468                                 sizeof(struct comedi_buf_page) * n_pages);
 469                         pages = vmalloc(sizeof(struct page *) * n_pages);
 470                 }
 471                 if (pages) {
 472                         for (i = 0; i < n_pages; i++) {
 473                                 if (s->async_dma_dir != DMA_NONE) {
 474                                         async->buf_page_list[i].virt_addr =
 475                                                 dma_alloc_coherent(dev->hw_dev,
 476                                                 PAGE_SIZE,
 477                                                 &async->buf_page_list[i].
 478                                                 dma_addr,
 479                                                 GFP_KERNEL | __GFP_COMP);
 480                                 } else {
 481                                         async->buf_page_list[i].virt_addr =
 482                                                 (void *)
 483                                                 get_zeroed_page(GFP_KERNEL);
 484                                 }
 485                                 if (async->buf_page_list[i].virt_addr == NULL) {
 486                                         break;
 487                                 }
 488                                 mem_map_reserve(virt_to_page(async->
 489                                                 buf_page_list[i].virt_addr));
 490                                 pages[i] =
 491                                         virt_to_page(async->buf_page_list[i].
 492                                         virt_addr);
 493                         }
 494                 }
 495                 if (i == n_pages) {
 496                         async->prealloc_buf =
 497                                 vmap(pages, n_pages, VM_MAP,
 498                                 PAGE_KERNEL_NOCACHE);
 499                 }
 500                 if (pages) {
 501                         vfree(pages);
 502                 }
 503                 if (async->prealloc_buf == NULL) {
 504                         /* Some allocation failed above. */
 505                         if (async->buf_page_list) {
 506                                 for (i = 0; i < n_pages; i++) {
 507                                         if (async->buf_page_list[i].virt_addr ==
 508                                                 NULL) {
 509                                                 break;
 510                                         }
 511                                         mem_map_unreserve(virt_to_page(async->
 512                                                         buf_page_list[i].
 513                                                         virt_addr));
 514                                         if (s->async_dma_dir != DMA_NONE) {
 515                                                 dma_free_coherent(dev->hw_dev,
 516                                                         PAGE_SIZE,
 517                                                         async->buf_page_list[i].
 518                                                         virt_addr,
 519                                                         async->buf_page_list[i].
 520                                                         dma_addr);
 521                                         } else {
 522                                                 free_page((unsigned long)async->
 523                                                         buf_page_list[i].
 524                                                         virt_addr);
 525                                         }
 526                                 }
 527                                 vfree(async->buf_page_list);
 528                                 async->buf_page_list = NULL;
 529                         }
 530                         return -ENOMEM;
 531                 }
 532                 async->n_buf_pages = n_pages;
 533         }
 534         async->prealloc_bufsz = new_size;
 535
 536         return 0;
 537 }
 538
 539 /* munging is applied to data by core as it passes between user
 540  * and kernel space */
 541 unsigned int comedi_buf_munge(comedi_async * async, unsigned int num_bytes)
 542 {
 543         comedi_subdevice *s = async->subdevice;
 544         unsigned int count = 0;
 545         const unsigned num_sample_bytes = bytes_per_sample(s);
 546
 547         if (s->munge == NULL || (async->cmd.flags & CMDF_RAWDATA)) {
 548                 async->munge_count += num_bytes;
 549                 if ((int)(async->munge_count - async->buf_write_count) > 0)
 550                         BUG();
 551                 return num_bytes;
 552         }
 553         /* don't munge partial samples */
 554         num_bytes -= num_bytes % num_sample_bytes;
 555         while (count < num_bytes) {
 556                 int block_size;
 557
 558                 block_size = num_bytes - count;
 559                 if (block_size < 0) {
 560                         rt_printk("%s: %s: bug! block_size is negative\n",
 561                                 __FILE__, __func__);
 562                         break;
 563                 }
 564                 if ((int)(async->munge_ptr + block_size -
 565                                 async->prealloc_bufsz) > 0)
 566                         block_size = async->prealloc_bufsz - async->munge_ptr;
 567
 568                 s->munge(s->device, s, async->prealloc_buf + async->munge_ptr,
 569                         block_size, async->munge_chan);
 570
 571                 smp_wmb();      /* barrier insures data is munged in buffer before munge_count is incremented */
 572
 573                 async->munge_chan += block_size / num_sample_bytes;
 574                 async->munge_chan %= async->cmd.chanlist_len;
 575                 async->munge_count += block_size;
 576                 async->munge_ptr += block_size;
 577                 async->munge_ptr %= async->prealloc_bufsz;
 578                 count += block_size;
 579         }
 580         if ((int)(async->munge_count - async->buf_write_count) > 0)
 581                 BUG();
 582         return count;
 583 }
 584
 585 unsigned int comedi_buf_write_n_available(comedi_async * async)
 586 {
 587         unsigned int free_end;
 588         unsigned int nbytes;
 589
 590         if (async == NULL)
 591                 return 0;
 592
 593         free_end = async->buf_read_count + async->prealloc_bufsz;
 594         nbytes = free_end - async->buf_write_alloc_count;
 595         nbytes -= nbytes % bytes_per_sample(async->subdevice);
 596         /* barrier insures the read of buf_read_count in this
 597            query occurs before any following writes to the buffer which
 598            might be based on the return value from this query.
 599          */
 600         smp_mb();
 601         return nbytes;
 602 }
 603
 604 /* allocates chunk for the writer from free buffer space */
 605 unsigned int comedi_buf_write_alloc(comedi_async * async, unsigned int nbytes)
 606 {
 607         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 608
 609         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0) {
 610                 nbytes = free_end - async->buf_write_alloc_count;
 611         }
 612         async->buf_write_alloc_count += nbytes;
 613         /* barrier insures the read of buf_read_count above occurs before
 614            we write data to the write-alloc'ed buffer space */
 615         smp_mb();
 616         return nbytes;
 617 }
 618
 619 /* allocates nothing unless it can completely fulfill the request */
 620 unsigned int comedi_buf_write_alloc_strict(comedi_async * async,
 621         unsigned int nbytes)
 622 {
 623         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
 624
 625         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0) {
 626                 nbytes = 0;
 627         }
 628         async->buf_write_alloc_count += nbytes;
 629         /* barrier insures the read of buf_read_count above occurs before
 630            we write data to the write-alloc'ed buffer space */
 631         smp_mb();
 632         return nbytes;
 633 }
 634
 635 /* transfers a chunk from writer to filled buffer space */
 636 unsigned comedi_buf_write_free(comedi_async * async, unsigned int nbytes)
 637 {
 638         if ((int)(async->buf_write_count + nbytes -
 639                         async->buf_write_alloc_count) > 0) {
 640                 rt_printk
 641                         ("comedi: attempted to write-free more bytes than have been write-allocated.\n");
 642                 nbytes = async->buf_write_alloc_count - async->buf_write_count;
 643         }
 644         async->buf_write_count += nbytes;
 645         async->buf_write_ptr += nbytes;
 646         comedi_buf_munge(async, async->buf_write_count - async->munge_count);
 647         if (async->buf_write_ptr >= async->prealloc_bufsz) {
 648                 async->buf_write_ptr %= async->prealloc_bufsz;
 649         }
 650         return nbytes;
 651 }
 652
 653 /* allocates a chunk for the reader from filled (and munged) buffer space */
 654 unsigned comedi_buf_read_alloc(comedi_async * async, unsigned nbytes)
 655 {
 656         if ((int)(async->buf_read_alloc_count + nbytes - async->munge_count) >
 657                 0) {
 658                 nbytes = async->munge_count - async->buf_read_alloc_count;
 659         }
 660         async->buf_read_alloc_count += nbytes;
 661         /* barrier insures read of munge_count occurs before we actually read
 662            data out of buffer */
 663         smp_rmb();
 664         return nbytes;
 665 }
 666
 667 /* transfers control of a chunk from reader to free buffer space */
 668 unsigned comedi_buf_read_free(comedi_async * async, unsigned int nbytes)
 669 {
 670         /*  barrier insures data has been read out of buffer before read count is incremented */
 671         smp_mb();
 672         if ((int)(async->buf_read_count + nbytes -
 673                         async->buf_read_alloc_count) > 0) {
 674                 rt_printk
 675                         ("comedi: attempted to read-free more bytes than have been read-allocated.\n");
 676                 nbytes = async->buf_read_alloc_count - async->buf_read_count;
 677         }
 678         async->buf_read_count += nbytes;
 679         async->buf_read_ptr += nbytes;
 680         async->buf_read_ptr %= async->prealloc_bufsz;
 681         return nbytes;
 682 }
 683
 684 void comedi_buf_memcpy_to(comedi_async * async, unsigned int offset,
 685         const void *data, unsigned int num_bytes)
 686 {
 687         unsigned int write_ptr = async->buf_write_ptr + offset;
 688
 689         if (write_ptr >= async->prealloc_bufsz)
 690                 write_ptr %= async->prealloc_bufsz;
 691
 692         while (num_bytes) {
 693                 unsigned int block_size;
 694
 695                 if (write_ptr + num_bytes > async->prealloc_bufsz)
 696                         block_size = async->prealloc_bufsz - write_ptr;
 697                 else
 698                         block_size = num_bytes;
 699
 700                 memcpy(async->prealloc_buf + write_ptr, data, block_size);
 701
 702                 data += block_size;
 703                 num_bytes -= block_size;
 704
 705                 write_ptr = 0;
 706         }
 707 }
 708
 709 void comedi_buf_memcpy_from(comedi_async * async, unsigned int offset,
 710         void *dest, unsigned int nbytes)
 711 {
 712         void *src;
 713         unsigned int read_ptr = async->buf_read_ptr + offset;
 714
 715         if (read_ptr >= async->prealloc_bufsz)
 716                 read_ptr %= async->prealloc_bufsz;
 717
 718         while (nbytes) {
 719                 unsigned int block_size;
 720
 721                 src = async->prealloc_buf + read_ptr;
 722
 723                 if (nbytes >= async->prealloc_bufsz - read_ptr)
 724                         block_size = async->prealloc_bufsz - read_ptr;
 725                 else
 726                         block_size = nbytes;
 727
 728                 memcpy(dest, src, block_size);
 729                 nbytes -= block_size;
 730                 dest += block_size;
 731                 read_ptr = 0;
 732         }
 733 }
 734
 735 unsigned int comedi_buf_read_n_available(comedi_async * async)
 736 {
 737         unsigned num_bytes;
 738
 739         if (async == NULL)
 740                 return 0;
 741         num_bytes = async->munge_count - async->buf_read_count;
 742         /* barrier insures the read of munge_count in this
 743            query occurs before any following reads of the buffer which
 744            might be based on the return value from this query.
 745          */
 746         smp_rmb();
 747         return num_bytes;
 748 }
 749
 750 int comedi_buf_get(comedi_async * async, sampl_t * x)
 751 {
 752         unsigned int n = comedi_buf_read_n_available(async);
 753
 754         if (n < sizeof(sampl_t))
 755                 return 0;
 756         comedi_buf_read_alloc(async, sizeof(sampl_t));
 757         *x = *(sampl_t *) (async->prealloc_buf + async->buf_read_ptr);
 758         comedi_buf_read_free(async, sizeof(sampl_t));
 759         return 1;
 760 }
 761
 762 int comedi_buf_put(comedi_async * async, sampl_t x)
 763 {
 764         unsigned int n = comedi_buf_write_alloc_strict(async, sizeof(sampl_t));
 765
 766         if (n < sizeof(sampl_t)) {
 767                 async->events |= COMEDI_CB_ERROR;
 768                 return 0;
 769         }
 770         *(sampl_t *) (async->prealloc_buf + async->buf_write_ptr) = x;
 771         comedi_buf_write_free(async, sizeof(sampl_t));
 772         return 1;
 773 }
 774
 775 void comedi_reset_async_buf(comedi_async * async)
 776 {
 777         async->buf_write_alloc_count = 0;
 778         async->buf_write_count = 0;
 779         async->buf_read_alloc_count = 0;
 780         async->buf_read_count = 0;
 781
 782         async->buf_write_ptr = 0;
 783         async->buf_read_ptr = 0;
 784
 785         async->cur_chan = 0;
 786         async->scan_progress = 0;
 787         async->munge_chan = 0;
 788         async->munge_count = 0;
 789         async->munge_ptr = 0;
 790
 791         async->events = 0;
 792 }
 793
 794 int comedi_auto_config(struct device *hardware_device, const char *board_name, const int *options, unsigned num_options)
 795 {
 796         comedi_devconfig it;
 797         int minor;
 798         struct comedi_device_file_info *dev_file_info;
 799         int retval;
 800         unsigned *private_data = NULL;
 801
 802         if (!comedi_autoconfig) {
 803                 dev_set_drvdata(hardware_device, NULL);
 804                 return 0;
 805         }
 806
 807         minor = comedi_alloc_board_minor(hardware_device);
 808         if(minor < 0) return minor;
 809
 810         private_data = kmalloc(sizeof(unsigned), GFP_KERNEL);
 811         if (private_data == NULL) {
 812                 retval = -ENOMEM;
 813                 goto cleanup;
 814         }
 815         *private_data = minor;
 816         dev_set_drvdata(hardware_device, private_data);
 817
 818         dev_file_info = comedi_get_device_file_info(minor);
 819
 820         memset(&it, 0, sizeof(it));
 821         strncpy(it.board_name, board_name, COMEDI_NAMELEN);
 822         it.board_name[COMEDI_NAMELEN - 1] = '\0';
 823         BUG_ON(num_options > COMEDI_NDEVCONFOPTS);
 824         memcpy(it.options, options, num_options * sizeof(int));
 825
 826         mutex_lock(&dev_file_info->device->mutex);
 827         retval = comedi_device_attach(dev_file_info->device, &it);
 828         mutex_unlock(&dev_file_info->device->mutex);
 829
 830 cleanup:
 831         if(retval < 0)
 832         {
 833                 kfree(private_data);
 834                 comedi_free_board_minor(minor);
 835         }
 836         return retval;
 837 }
 838
 839 void comedi_auto_unconfig(struct device *hardware_device)
 840 {
 841         unsigned *minor = (unsigned *)dev_get_drvdata(hardware_device);
 842         if(minor == NULL) return;
 843
 844         BUG_ON(*minor >= COMEDI_NUM_BOARD_MINORS);
 845
 846         comedi_free_board_minor(*minor);
 847         dev_set_drvdata(hardware_device, NULL);
 848         kfree(minor);
 849 }
 850
 851 int comedi_pci_auto_config(struct pci_dev *pcidev, const char *board_name)
 852 {
 853         int options[2];
 854
 855         /*  pci bus */
 856         options[0] = pcidev->bus->number;
 857         /*  pci slot */
 858         options[1] = PCI_SLOT(pcidev->devfn);
 859
 860         return comedi_auto_config(&pcidev->dev, board_name, options, sizeof(options) / sizeof(options[0]));
 861 }
 862
 863 void comedi_pci_auto_unconfig(struct pci_dev *pcidev)
 864 {
 865         comedi_auto_unconfig(&pcidev->dev);
 866 }
 867
 868 int comedi_usb_auto_config(struct usb_device *usbdev,
 869         const char *board_name)
 870 {
 871         BUG_ON(usbdev == NULL);
 872         return comedi_auto_config(&usbdev->dev, board_name, NULL, 0);
 873 }
 874
 875 void comedi_usb_auto_unconfig(struct usb_device *usbdev)
 876 {
 877         BUG_ON(usbdev == NULL);
 878         comedi_auto_unconfig(&usbdev->dev);
 879 }