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
  19 #include <linux/device.h>
  20 #include <linux/module.h>
  21 #include <linux/errno.h>
  22 #include <linux/kconfig.h>
  23 #include <linux/kernel.h>
  24 #include <linux/sched.h>
  25 #include <linux/fcntl.h>
  26 #include <linux/delay.h>
  27 #include <linux/ioport.h>
  28 #include <linux/mm.h>
  29 #include <linux/slab.h>
  30 #include <linux/highmem.h>      /* for SuSE brokenness */
  31 #include <linux/vmalloc.h>
  32 #include <linux/cdev.h>
  33 #include <linux/dma-mapping.h>
  34 #include <linux/io.h>
  35 #include <linux/interrupt.h>
  36 #include <linux/firmware.h>
  37
  38 #include "comedidev.h"
  39 #include "comedi_internal.h"
  40
  41 struct comedi_driver *comedi_drivers;
  42
  43 int comedi_set_hw_dev(struct comedi_device *dev, struct device *hw_dev)
  44 {
  45         if (hw_dev == dev->hw_dev)
  46                 return 0;
  47         if (dev->hw_dev != NULL)
  48                 return -EEXIST;
  49         dev->hw_dev = get_device(hw_dev);
  50         return 0;
  51 }
  52 EXPORT_SYMBOL_GPL(comedi_set_hw_dev);
  53
  54 static void comedi_clear_hw_dev(struct comedi_device *dev)
  55 {
  56         put_device(dev->hw_dev);
  57         dev->hw_dev = NULL;
  58 }
  59
  60 int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices)
  61 {
  62         struct comedi_subdevice *s;
  63         int i;
  64
  65         if (num_subdevices < 1)
  66                 return -EINVAL;
  67
  68         s = kcalloc(num_subdevices, sizeof(*s), GFP_KERNEL);
  69         if (!s)
  70                 return -ENOMEM;
  71         dev->subdevices = s;
  72         dev->n_subdevices = num_subdevices;
  73
  74         for (i = 0; i < num_subdevices; ++i) {
  75                 s = &dev->subdevices[i];
  76                 s->device = dev;
  77                 s->index = i;
  78                 s->async_dma_dir = DMA_NONE;
  79                 spin_lock_init(&s->spin_lock);
  80                 s->minor = -1;
  81         }
  82         return 0;
  83 }
  84 EXPORT_SYMBOL_GPL(comedi_alloc_subdevices);
  85
  86 static void cleanup_device(struct comedi_device *dev)
  87 {
  88         int i;
  89         struct comedi_subdevice *s;
  90
  91         if (dev->subdevices) {
  92                 for (i = 0; i < dev->n_subdevices; i++) {
  93                         s = &dev->subdevices[i];
  94                         if (s->runflags & SRF_FREE_SPRIV)
  95                                 kfree(s->private);
  96                         comedi_free_subdevice_minor(s);
  97                         if (s->async) {
  98                                 comedi_buf_alloc(dev, s, 0);
  99                                 kfree(s->async);
 100                         }
 101                 }
 102                 kfree(dev->subdevices);
 103                 dev->subdevices = NULL;
 104                 dev->n_subdevices = 0;
 105         }
 106         kfree(dev->private);
 107         dev->private = NULL;
 108         dev->driver = NULL;
 109         dev->board_name = NULL;
 110         dev->board_ptr = NULL;
 111         dev->iobase = 0;
 112         dev->iolen = 0;
 113         dev->ioenabled = false;
 114         dev->irq = 0;
 115         dev->read_subdev = NULL;
 116         dev->write_subdev = NULL;
 117         dev->open = NULL;
 118         dev->close = NULL;
 119         comedi_clear_hw_dev(dev);
 120 }
 121
 122 void comedi_device_detach(struct comedi_device *dev)
 123 {
 124         dev->attached = false;
 125         if (dev->driver)
 126                 dev->driver->detach(dev);
 127         cleanup_device(dev);
 128 }
 129
 130 static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s)
 131 {
 132         return -EINVAL;
 133 }
 134
 135 int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s,
 136                struct comedi_insn *insn, unsigned int *data)
 137 {
 138         return -EINVAL;
 139 }
 140
 141 static int insn_rw_emulate_bits(struct comedi_device *dev,
 142                                 struct comedi_subdevice *s,
 143                                 struct comedi_insn *insn, unsigned int *data)
 144 {
 145         struct comedi_insn new_insn;
 146         int ret;
 147         static const unsigned channels_per_bitfield = 32;
 148
 149         unsigned chan = CR_CHAN(insn->chanspec);
 150         const unsigned base_bitfield_channel =
 151             (chan < channels_per_bitfield) ? 0 : chan;
 152         unsigned int new_data[2];
 153         memset(new_data, 0, sizeof(new_data));
 154         memset(&new_insn, 0, sizeof(new_insn));
 155         new_insn.insn = INSN_BITS;
 156         new_insn.chanspec = base_bitfield_channel;
 157         new_insn.n = 2;
 158         new_insn.subdev = insn->subdev;
 159
 160         if (insn->insn == INSN_WRITE) {
 161                 if (!(s->subdev_flags & SDF_WRITABLE))
 162                         return -EINVAL;
 163                 new_data[0] = 1 << (chan - base_bitfield_channel); /* mask */
 164                 new_data[1] = data[0] ? (1 << (chan - base_bitfield_channel))
 165                               : 0; /* bits */
 166         }
 167
 168         ret = s->insn_bits(dev, s, &new_insn, new_data);
 169         if (ret < 0)
 170                 return ret;
 171
 172         if (insn->insn == INSN_READ)
 173                 data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1;
 174
 175         return 1;
 176 }
 177
 178 static int __comedi_device_postconfig_async(struct comedi_device *dev,
 179                                             struct comedi_subdevice *s)
 180 {
 181         struct comedi_async *async;
 182         unsigned int buf_size;
 183         int ret;
 184
 185         if ((s->subdev_flags & (SDF_CMD_READ | SDF_CMD_WRITE)) == 0) {
 186                 dev_warn(dev->class_dev,
 187                          "async subdevices must support SDF_CMD_READ or SDF_CMD_WRITE\n");
 188                 return -EINVAL;
 189         }
 190         if (!s->do_cmdtest) {
 191                 dev_warn(dev->class_dev,
 192                          "async subdevices must have a do_cmdtest() function\n");
 193                 return -EINVAL;
 194         }
 195
 196         async = kzalloc(sizeof(*async), GFP_KERNEL);
 197         if (!async)
 198                 return -ENOMEM;
 199
 200         init_waitqueue_head(&async->wait_head);
 201         async->subdevice = s;
 202         s->async = async;
 203
 204         async->max_bufsize = comedi_default_buf_maxsize_kb * 1024;
 205         buf_size = comedi_default_buf_size_kb * 1024;
 206         if (buf_size > async->max_bufsize)
 207                 buf_size = async->max_bufsize;
 208
 209         if (comedi_buf_alloc(dev, s, buf_size) < 0) {
 210                 dev_warn(dev->class_dev, "Buffer allocation failed\n");
 211                 return -ENOMEM;
 212         }
 213         if (s->buf_change) {
 214                 ret = s->buf_change(dev, s, buf_size);
 215                 if (ret < 0)
 216                         return ret;
 217         }
 218
 219         comedi_alloc_subdevice_minor(s);
 220
 221         return 0;
 222 }
 223
 224 static int __comedi_device_postconfig(struct comedi_device *dev)
 225 {
 226         struct comedi_subdevice *s;
 227         int ret;
 228         int i;
 229
 230         for (i = 0; i < dev->n_subdevices; i++) {
 231                 s = &dev->subdevices[i];
 232
 233                 if (s->type == COMEDI_SUBD_UNUSED)
 234                         continue;
 235
 236                 if (s->len_chanlist == 0)
 237                         s->len_chanlist = 1;
 238
 239                 if (s->do_cmd) {
 240                         ret = __comedi_device_postconfig_async(dev, s);
 241                         if (ret)
 242                                 return ret;
 243                 }
 244
 245                 if (!s->range_table && !s->range_table_list)
 246                         s->range_table = &range_unknown;
 247
 248                 if (!s->insn_read && s->insn_bits)
 249                         s->insn_read = insn_rw_emulate_bits;
 250                 if (!s->insn_write && s->insn_bits)
 251                         s->insn_write = insn_rw_emulate_bits;
 252
 253                 if (!s->insn_read)
 254                         s->insn_read = insn_inval;
 255                 if (!s->insn_write)
 256                         s->insn_write = insn_inval;
 257                 if (!s->insn_bits)
 258                         s->insn_bits = insn_inval;
 259                 if (!s->insn_config)
 260                         s->insn_config = insn_inval;
 261
 262                 if (!s->poll)
 263                         s->poll = poll_invalid;
 264         }
 265
 266         return 0;
 267 }
 268
 269 /* do a little post-config cleanup */
 270 static int comedi_device_postconfig(struct comedi_device *dev)
 271 {
 272         int ret;
 273
 274         ret = __comedi_device_postconfig(dev);
 275         if (ret < 0)
 276                 return ret;
 277         smp_wmb();
 278         dev->attached = true;
 279         return 0;
 280 }
 281
 282 /*
 283  * Generic recognize function for drivers that register their supported
 284  * board names.
 285  *
 286  * 'driv->board_name' points to a 'const char *' member within the
 287  * zeroth element of an array of some private board information
 288  * structure, say 'struct foo_board' containing a member 'const char
 289  * *board_name' that is initialized to point to a board name string that
 290  * is one of the candidates matched against this function's 'name'
 291  * parameter.
 292  *
 293  * 'driv->offset' is the size of the private board information
 294  * structure, say 'sizeof(struct foo_board)', and 'driv->num_names' is
 295  * the length of the array of private board information structures.
 296  *
 297  * If one of the board names in the array of private board information
 298  * structures matches the name supplied to this function, the function
 299  * returns a pointer to the pointer to the board name, otherwise it
 300  * returns NULL.  The return value ends up in the 'board_ptr' member of
 301  * a 'struct comedi_device' that the low-level comedi driver's
 302  * 'attach()' hook can convert to a point to a particular element of its
 303  * array of private board information structures by subtracting the
 304  * offset of the member that points to the board name.  (No subtraction
 305  * is required if the board name pointer is the first member of the
 306  * private board information structure, which is generally the case.)
 307  */
 308 static void *comedi_recognize(struct comedi_driver *driv, const char *name)
 309 {
 310         char **name_ptr = (char **)driv->board_name;
 311         int i;
 312
 313         for (i = 0; i < driv->num_names; i++) {
 314                 if (strcmp(*name_ptr, name) == 0)
 315                         return name_ptr;
 316                 name_ptr = (void *)name_ptr + driv->offset;
 317         }
 318
 319         return NULL;
 320 }
 321
 322 static void comedi_report_boards(struct comedi_driver *driv)
 323 {
 324         unsigned int i;
 325         const char *const *name_ptr;
 326
 327         pr_info("comedi: valid board names for %s driver are:\n",
 328                 driv->driver_name);
 329
 330         name_ptr = driv->board_name;
 331         for (i = 0; i < driv->num_names; i++) {
 332                 pr_info(" %s\n", *name_ptr);
 333                 name_ptr = (const char **)((char *)name_ptr + driv->offset);
 334         }
 335
 336         if (driv->num_names == 0)
 337                 pr_info(" %s\n", driv->driver_name);
 338 }
 339
 340 /**
 341  * comedi_load_firmware() - Request and load firmware for a device.
 342  * @dev: comedi_device struct
 343  * @hw_device: device struct for the comedi_device
 344  * @name: the name of the firmware image
 345  * @cb: callback to the upload the firmware image
 346  * @context: private context from the driver
 347  */
 348 int comedi_load_firmware(struct comedi_device *dev,
 349                          struct device *device,
 350                          const char *name,
 351                          int (*cb)(struct comedi_device *dev,
 352                                    const u8 *data, size_t size,
 353                                    unsigned long context),
 354                          unsigned long context)
 355 {
 356         const struct firmware *fw;
 357         int ret;
 358
 359         if (!cb)
 360                 return -EINVAL;
 361
 362         ret = request_firmware(&fw, name, device);
 363         if (ret == 0) {
 364                 ret = cb(dev, fw->data, fw->size, context);
 365                 release_firmware(fw);
 366         }
 367
 368         return ret;
 369 }
 370 EXPORT_SYMBOL_GPL(comedi_load_firmware);
 371
 372 /**
 373  * __comedi_request_region() - Request an I/O reqion for a legacy driver.
 374  * @dev: comedi_device struct
 375  * @start: base address of the I/O reqion
 376  * @len: length of the I/O region
 377  */
 378 int __comedi_request_region(struct comedi_device *dev,
 379                             unsigned long start, unsigned long len)
 380 {
 381         if (!start) {
 382                 dev_warn(dev->class_dev,
 383                          "%s: a I/O base address must be specified\n",
 384                          dev->board_name);
 385                 return -EINVAL;
 386         }
 387
 388         if (!request_region(start, len, dev->board_name)) {
 389                 dev_warn(dev->class_dev, "%s: I/O port conflict (%#lx,%lu)\n",
 390                          dev->board_name, start, len);
 391                 return -EIO;
 392         }
 393
 394         return 0;
 395 }
 396 EXPORT_SYMBOL_GPL(__comedi_request_region);
 397
 398 /**
 399  * comedi_request_region() - Request an I/O reqion for a legacy driver.
 400  * @dev: comedi_device struct
 401  * @start: base address of the I/O reqion
 402  * @len: length of the I/O region
 403  */
 404 int comedi_request_region(struct comedi_device *dev,
 405                           unsigned long start, unsigned long len)
 406 {
 407         int ret;
 408
 409         ret = __comedi_request_region(dev, start, len);
 410         if (ret == 0) {
 411                 dev->iobase = start;
 412                 dev->iolen = len;
 413         }
 414
 415         return ret;
 416 }
 417 EXPORT_SYMBOL_GPL(comedi_request_region);
 418
 419 /**
 420  * comedi_legacy_detach() - A generic (*detach) function for legacy drivers.
 421  * @dev: comedi_device struct
 422  */
 423 void comedi_legacy_detach(struct comedi_device *dev)
 424 {
 425         if (dev->irq) {
 426                 free_irq(dev->irq, dev);
 427                 dev->irq = 0;
 428         }
 429         if (dev->iobase && dev->iolen) {
 430                 release_region(dev->iobase, dev->iolen);
 431                 dev->iobase = 0;
 432                 dev->iolen = 0;
 433         }
 434 }
 435 EXPORT_SYMBOL_GPL(comedi_legacy_detach);
 436
 437 int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 438 {
 439         struct comedi_driver *driv;
 440         int ret;
 441
 442         if (dev->attached)
 443                 return -EBUSY;
 444
 445         for (driv = comedi_drivers; driv; driv = driv->next) {
 446                 if (!try_module_get(driv->module))
 447                         continue;
 448                 if (driv->num_names) {
 449                         dev->board_ptr = comedi_recognize(driv, it->board_name);
 450                         if (dev->board_ptr)
 451                                 break;
 452                 } else if (strcmp(driv->driver_name, it->board_name) == 0)
 453                         break;
 454                 module_put(driv->module);
 455         }
 456         if (driv == NULL) {
 457                 /*  recognize has failed if we get here */
 458                 /*  report valid board names before returning error */
 459                 for (driv = comedi_drivers; driv; driv = driv->next) {
 460                         if (!try_module_get(driv->module))
 461                                 continue;
 462                         comedi_report_boards(driv);
 463                         module_put(driv->module);
 464                 }
 465                 return -EIO;
 466         }
 467         if (driv->attach == NULL) {
 468                 /* driver does not support manual configuration */
 469                 dev_warn(dev->class_dev,
 470                          "driver '%s' does not support attach using comedi_config\n",
 471                          driv->driver_name);
 472                 module_put(driv->module);
 473                 return -ENOSYS;
 474         }
 475         /* initialize dev->driver here so
 476          * comedi_error() can be called from attach */
 477         dev->driver = driv;
 478         dev->board_name = dev->board_ptr ? *(const char **)dev->board_ptr
 479                                          : dev->driver->driver_name;
 480         ret = driv->attach(dev, it);
 481         if (ret >= 0)
 482                 ret = comedi_device_postconfig(dev);
 483         if (ret < 0) {
 484                 comedi_device_detach(dev);
 485                 module_put(dev->driver->module);
 486         }
 487         /* On success, the driver module count has been incremented. */
 488         return ret;
 489 }
 490
 491 int comedi_auto_config(struct device *hardware_device,
 492                        struct comedi_driver *driver, unsigned long context)
 493 {
 494         struct comedi_device *dev;
 495         int ret;
 496
 497         if (!hardware_device) {
 498                 pr_warn("BUG! comedi_auto_config called with NULL hardware_device\n");
 499                 return -EINVAL;
 500         }
 501         if (!driver) {
 502                 dev_warn(hardware_device,
 503                          "BUG! comedi_auto_config called with NULL comedi driver\n");
 504                 return -EINVAL;
 505         }
 506
 507         if (!driver->auto_attach) {
 508                 dev_warn(hardware_device,
 509                          "BUG! comedi driver '%s' has no auto_attach handler\n",
 510                          driver->driver_name);
 511                 return -EINVAL;
 512         }
 513
 514         dev = comedi_alloc_board_minor(hardware_device);
 515         if (IS_ERR(dev))
 516                 return PTR_ERR(dev);
 517         /* Note: comedi_alloc_board_minor() locked dev->mutex. */
 518
 519         dev->driver = driver;
 520         dev->board_name = dev->driver->driver_name;
 521         ret = driver->auto_attach(dev, context);
 522         if (ret >= 0)
 523                 ret = comedi_device_postconfig(dev);
 524         if (ret < 0)
 525                 comedi_device_detach(dev);
 526         mutex_unlock(&dev->mutex);
 527
 528         if (ret < 0)
 529                 comedi_release_hardware_device(hardware_device);
 530         return ret;
 531 }
 532 EXPORT_SYMBOL_GPL(comedi_auto_config);
 533
 534 void comedi_auto_unconfig(struct device *hardware_device)
 535 {
 536         if (hardware_device == NULL)
 537                 return;
 538         comedi_release_hardware_device(hardware_device);
 539 }
 540 EXPORT_SYMBOL_GPL(comedi_auto_unconfig);
 541
 542 int comedi_driver_register(struct comedi_driver *driver)
 543 {
 544         driver->next = comedi_drivers;
 545         comedi_drivers = driver;
 546
 547         return 0;
 548 }
 549 EXPORT_SYMBOL_GPL(comedi_driver_register);
 550
 551 int comedi_driver_unregister(struct comedi_driver *driver)
 552 {
 553         struct comedi_driver *prev;
 554         int i;
 555
 556         /* check for devices using this driver */
 557         for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
 558                 struct comedi_device *dev = comedi_dev_from_minor(i);
 559
 560                 if (!dev)
 561                         continue;
 562
 563                 mutex_lock(&dev->mutex);
 564                 if (dev->attached && dev->driver == driver) {
 565                         if (dev->use_count)
 566                                 dev_warn(dev->class_dev,
 567                                          "BUG! detaching device with use_count=%d\n",
 568                                          dev->use_count);
 569                         comedi_device_detach(dev);
 570                 }
 571                 mutex_unlock(&dev->mutex);
 572         }
 573
 574         if (comedi_drivers == driver) {
 575                 comedi_drivers = driver->next;
 576                 return 0;
 577         }
 578
 579         for (prev = comedi_drivers; prev->next; prev = prev->next) {
 580                 if (prev->next == driver) {
 581                         prev->next = driver->next;
 582                         return 0;
 583                 }
 584         }
 585         return -EINVAL;
 586 }
 587 EXPORT_SYMBOL_GPL(comedi_driver_unregister);