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