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/ioport.h>
  27 #include <linux/mm.h>
  28 #include <linux/slab.h>
  29 #include <linux/highmem.h>      /* for SuSE brokenness */
  30 #include <linux/vmalloc.h>
  31 #include <linux/cdev.h>
  32 #include <linux/dma-mapping.h>
  33 #include <linux/io.h>
  34 #include <linux/interrupt.h>
  35 #include <linux/firmware.h>
  36
  37 #include "comedidev.h"
  38 #include "comedi_internal.h"
  39
  40 struct comedi_driver *comedi_drivers;
  41 DEFINE_MUTEX(comedi_drivers_list_lock);
  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 /**
  61  * comedi_alloc_devpriv() - Allocate memory for the device private data.
  62  * @dev: comedi_device struct
  63  * @size: size of the memory to allocate
  64  */
  65 void *comedi_alloc_devpriv(struct comedi_device *dev, size_t size)
  66 {
  67         dev->private = kzalloc(size, GFP_KERNEL);
  68         return dev->private;
  69 }
  70 EXPORT_SYMBOL_GPL(comedi_alloc_devpriv);
  71
  72 int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices)
  73 {
  74         struct comedi_subdevice *s;
  75         int i;
  76
  77         if (num_subdevices < 1)
  78                 return -EINVAL;
  79
  80         s = kcalloc(num_subdevices, sizeof(*s), GFP_KERNEL);
  81         if (!s)
  82                 return -ENOMEM;
  83         dev->subdevices = s;
  84         dev->n_subdevices = num_subdevices;
  85
  86         for (i = 0; i < num_subdevices; ++i) {
  87                 s = &dev->subdevices[i];
  88                 s->device = dev;
  89                 s->index = i;
  90                 s->async_dma_dir = DMA_NONE;
  91                 spin_lock_init(&s->spin_lock);
  92                 s->minor = -1;
  93         }
  94         return 0;
  95 }
  96 EXPORT_SYMBOL_GPL(comedi_alloc_subdevices);
  97
  98 static void cleanup_device(struct comedi_device *dev)
  99 {
 100         int i;
 101         struct comedi_subdevice *s;
 102
 103         if (dev->subdevices) {
 104                 for (i = 0; i < dev->n_subdevices; i++) {
 105                         s = &dev->subdevices[i];
 106                         if (s->runflags & SRF_FREE_SPRIV)
 107                                 kfree(s->private);
 108                         comedi_free_subdevice_minor(s);
 109                         if (s->async) {
 110                                 comedi_buf_alloc(dev, s, 0);
 111                                 kfree(s->async);
 112                         }
 113                 }
 114                 kfree(dev->subdevices);
 115                 dev->subdevices = NULL;
 116                 dev->n_subdevices = 0;
 117         }
 118         kfree(dev->private);
 119         dev->private = NULL;
 120         dev->driver = NULL;
 121         dev->board_name = NULL;
 122         dev->board_ptr = NULL;
 123         dev->iobase = 0;
 124         dev->iolen = 0;
 125         dev->ioenabled = false;
 126         dev->irq = 0;
 127         dev->read_subdev = NULL;
 128         dev->write_subdev = NULL;
 129         dev->open = NULL;
 130         dev->close = NULL;
 131         comedi_clear_hw_dev(dev);
 132 }
 133
 134 void comedi_device_detach(struct comedi_device *dev)
 135 {
 136         dev->attached = false;
 137         if (dev->driver)
 138                 dev->driver->detach(dev);
 139         cleanup_device(dev);
 140 }
 141
 142 static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s)
 143 {
 144         return -EINVAL;
 145 }
 146
 147 int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s,
 148                struct comedi_insn *insn, unsigned int *data)
 149 {
 150         return -EINVAL;
 151 }
 152
 153 /**
 154  * comedi_dio_insn_config() - boilerplate (*insn_config) for DIO subdevices.
 155  * @dev: comedi_device struct
 156  * @s: comedi_subdevice struct
 157  * @insn: comedi_insn struct
 158  * @data: parameters for the @insn
 159  * @mask: io_bits mask for grouped channels
 160  */
 161 int comedi_dio_insn_config(struct comedi_device *dev,
 162                            struct comedi_subdevice *s,
 163                            struct comedi_insn *insn,
 164                            unsigned int *data,
 165                            unsigned int mask)
 166 {
 167         unsigned int chan_mask = 1 << CR_CHAN(insn->chanspec);
 168
 169         if (!mask)
 170                 mask = chan_mask;
 171
 172         switch (data[0]) {
 173         case INSN_CONFIG_DIO_INPUT:
 174                 s->io_bits &= ~mask;
 175                 break;
 176
 177         case INSN_CONFIG_DIO_OUTPUT:
 178                 s->io_bits |= mask;
 179                 break;
 180
 181         case INSN_CONFIG_DIO_QUERY:
 182                 data[1] = (s->io_bits & mask) ? COMEDI_OUTPUT : COMEDI_INPUT;
 183                 return insn->n;
 184
 185         default:
 186                 return -EINVAL;
 187         }
 188
 189         return 0;
 190 }
 191 EXPORT_SYMBOL_GPL(comedi_dio_insn_config);
 192
 193 static int insn_rw_emulate_bits(struct comedi_device *dev,
 194                                 struct comedi_subdevice *s,
 195                                 struct comedi_insn *insn, unsigned int *data)
 196 {
 197         struct comedi_insn new_insn;
 198         int ret;
 199         static const unsigned channels_per_bitfield = 32;
 200
 201         unsigned chan = CR_CHAN(insn->chanspec);
 202         const unsigned base_bitfield_channel =
 203             (chan < channels_per_bitfield) ? 0 : chan;
 204         unsigned int new_data[2];
 205         memset(new_data, 0, sizeof(new_data));
 206         memset(&new_insn, 0, sizeof(new_insn));
 207         new_insn.insn = INSN_BITS;
 208         new_insn.chanspec = base_bitfield_channel;
 209         new_insn.n = 2;
 210         new_insn.subdev = insn->subdev;
 211
 212         if (insn->insn == INSN_WRITE) {
 213                 if (!(s->subdev_flags & SDF_WRITABLE))
 214                         return -EINVAL;
 215                 new_data[0] = 1 << (chan - base_bitfield_channel); /* mask */
 216                 new_data[1] = data[0] ? (1 << (chan - base_bitfield_channel))
 217                               : 0; /* bits */
 218         }
 219
 220         ret = s->insn_bits(dev, s, &new_insn, new_data);
 221         if (ret < 0)
 222                 return ret;
 223
 224         if (insn->insn == INSN_READ)
 225                 data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1;
 226
 227         return 1;
 228 }
 229
 230 static int __comedi_device_postconfig_async(struct comedi_device *dev,
 231                                             struct comedi_subdevice *s)
 232 {
 233         struct comedi_async *async;
 234         unsigned int buf_size;
 235         int ret;
 236
 237         if ((s->subdev_flags & (SDF_CMD_READ | SDF_CMD_WRITE)) == 0) {
 238                 dev_warn(dev->class_dev,
 239                          "async subdevices must support SDF_CMD_READ or SDF_CMD_WRITE\n");
 240                 return -EINVAL;
 241         }
 242         if (!s->do_cmdtest) {
 243                 dev_warn(dev->class_dev,
 244                          "async subdevices must have a do_cmdtest() function\n");
 245                 return -EINVAL;
 246         }
 247
 248         async = kzalloc(sizeof(*async), GFP_KERNEL);
 249         if (!async)
 250                 return -ENOMEM;
 251
 252         init_waitqueue_head(&async->wait_head);
 253         async->subdevice = s;
 254         s->async = async;
 255
 256         async->max_bufsize = comedi_default_buf_maxsize_kb * 1024;
 257         buf_size = comedi_default_buf_size_kb * 1024;
 258         if (buf_size > async->max_bufsize)
 259                 buf_size = async->max_bufsize;
 260
 261         if (comedi_buf_alloc(dev, s, buf_size) < 0) {
 262                 dev_warn(dev->class_dev, "Buffer allocation failed\n");
 263                 return -ENOMEM;
 264         }
 265         if (s->buf_change) {
 266                 ret = s->buf_change(dev, s, buf_size);
 267                 if (ret < 0)
 268                         return ret;
 269         }
 270
 271         comedi_alloc_subdevice_minor(s);
 272
 273         return 0;
 274 }
 275
 276 static int __comedi_device_postconfig(struct comedi_device *dev)
 277 {
 278         struct comedi_subdevice *s;
 279         int ret;
 280         int i;
 281
 282         for (i = 0; i < dev->n_subdevices; i++) {
 283                 s = &dev->subdevices[i];
 284
 285                 if (s->type == COMEDI_SUBD_UNUSED)
 286                         continue;
 287
 288                 if (s->len_chanlist == 0)
 289                         s->len_chanlist = 1;
 290
 291                 if (s->do_cmd) {
 292                         ret = __comedi_device_postconfig_async(dev, s);
 293                         if (ret)
 294                                 return ret;
 295                 }
 296
 297                 if (!s->range_table && !s->range_table_list)
 298                         s->range_table = &range_unknown;
 299
 300                 if (!s->insn_read && s->insn_bits)
 301                         s->insn_read = insn_rw_emulate_bits;
 302                 if (!s->insn_write && s->insn_bits)
 303                         s->insn_write = insn_rw_emulate_bits;
 304
 305                 if (!s->insn_read)
 306                         s->insn_read = insn_inval;
 307                 if (!s->insn_write)
 308                         s->insn_write = insn_inval;
 309                 if (!s->insn_bits)
 310                         s->insn_bits = insn_inval;
 311                 if (!s->insn_config)
 312                         s->insn_config = insn_inval;
 313
 314                 if (!s->poll)
 315                         s->poll = poll_invalid;
 316         }
 317
 318         return 0;
 319 }
 320
 321 /* do a little post-config cleanup */
 322 static int comedi_device_postconfig(struct comedi_device *dev)
 323 {
 324         int ret;
 325
 326         ret = __comedi_device_postconfig(dev);
 327         if (ret < 0)
 328                 return ret;
 329         smp_wmb();
 330         dev->attached = true;
 331         return 0;
 332 }
 333
 334 /*
 335  * Generic recognize function for drivers that register their supported
 336  * board names.
 337  *
 338  * 'driv->board_name' points to a 'const char *' member within the
 339  * zeroth element of an array of some private board information
 340  * structure, say 'struct foo_board' containing a member 'const char
 341  * *board_name' that is initialized to point to a board name string that
 342  * is one of the candidates matched against this function's 'name'
 343  * parameter.
 344  *
 345  * 'driv->offset' is the size of the private board information
 346  * structure, say 'sizeof(struct foo_board)', and 'driv->num_names' is
 347  * the length of the array of private board information structures.
 348  *
 349  * If one of the board names in the array of private board information
 350  * structures matches the name supplied to this function, the function
 351  * returns a pointer to the pointer to the board name, otherwise it
 352  * returns NULL.  The return value ends up in the 'board_ptr' member of
 353  * a 'struct comedi_device' that the low-level comedi driver's
 354  * 'attach()' hook can convert to a point to a particular element of its
 355  * array of private board information structures by subtracting the
 356  * offset of the member that points to the board name.  (No subtraction
 357  * is required if the board name pointer is the first member of the
 358  * private board information structure, which is generally the case.)
 359  */
 360 static void *comedi_recognize(struct comedi_driver *driv, const char *name)
 361 {
 362         char **name_ptr = (char **)driv->board_name;
 363         int i;
 364
 365         for (i = 0; i < driv->num_names; i++) {
 366                 if (strcmp(*name_ptr, name) == 0)
 367                         return name_ptr;
 368                 name_ptr = (void *)name_ptr + driv->offset;
 369         }
 370
 371         return NULL;
 372 }
 373
 374 static void comedi_report_boards(struct comedi_driver *driv)
 375 {
 376         unsigned int i;
 377         const char *const *name_ptr;
 378
 379         pr_info("comedi: valid board names for %s driver are:\n",
 380                 driv->driver_name);
 381
 382         name_ptr = driv->board_name;
 383         for (i = 0; i < driv->num_names; i++) {
 384                 pr_info(" %s\n", *name_ptr);
 385                 name_ptr = (const char **)((char *)name_ptr + driv->offset);
 386         }
 387
 388         if (driv->num_names == 0)
 389                 pr_info(" %s\n", driv->driver_name);
 390 }
 391
 392 /**
 393  * comedi_load_firmware() - Request and load firmware for a device.
 394  * @dev: comedi_device struct
 395  * @hw_device: device struct for the comedi_device
 396  * @name: the name of the firmware image
 397  * @cb: callback to the upload the firmware image
 398  * @context: private context from the driver
 399  */
 400 int comedi_load_firmware(struct comedi_device *dev,
 401                          struct device *device,
 402                          const char *name,
 403                          int (*cb)(struct comedi_device *dev,
 404                                    const u8 *data, size_t size,
 405                                    unsigned long context),
 406                          unsigned long context)
 407 {
 408         const struct firmware *fw;
 409         int ret;
 410
 411         if (!cb)
 412                 return -EINVAL;
 413
 414         ret = request_firmware(&fw, name, device);
 415         if (ret == 0) {
 416                 ret = cb(dev, fw->data, fw->size, context);
 417                 release_firmware(fw);
 418         }
 419
 420         return ret < 0 ? ret : 0;
 421 }
 422 EXPORT_SYMBOL_GPL(comedi_load_firmware);
 423
 424 /**
 425  * __comedi_request_region() - Request an I/O reqion for a legacy driver.
 426  * @dev: comedi_device struct
 427  * @start: base address of the I/O reqion
 428  * @len: length of the I/O region
 429  */
 430 int __comedi_request_region(struct comedi_device *dev,
 431                             unsigned long start, unsigned long len)
 432 {
 433         if (!start) {
 434                 dev_warn(dev->class_dev,
 435                          "%s: a I/O base address must be specified\n",
 436                          dev->board_name);
 437                 return -EINVAL;
 438         }
 439
 440         if (!request_region(start, len, dev->board_name)) {
 441                 dev_warn(dev->class_dev, "%s: I/O port conflict (%#lx,%lu)\n",
 442                          dev->board_name, start, len);
 443                 return -EIO;
 444         }
 445
 446         return 0;
 447 }
 448 EXPORT_SYMBOL_GPL(__comedi_request_region);
 449
 450 /**
 451  * comedi_request_region() - Request an I/O reqion for a legacy driver.
 452  * @dev: comedi_device struct
 453  * @start: base address of the I/O reqion
 454  * @len: length of the I/O region
 455  */
 456 int comedi_request_region(struct comedi_device *dev,
 457                           unsigned long start, unsigned long len)
 458 {
 459         int ret;
 460
 461         ret = __comedi_request_region(dev, start, len);
 462         if (ret == 0) {
 463                 dev->iobase = start;
 464                 dev->iolen = len;
 465         }
 466
 467         return ret;
 468 }
 469 EXPORT_SYMBOL_GPL(comedi_request_region);
 470
 471 /**
 472  * comedi_legacy_detach() - A generic (*detach) function for legacy drivers.
 473  * @dev: comedi_device struct
 474  */
 475 void comedi_legacy_detach(struct comedi_device *dev)
 476 {
 477         if (dev->irq) {
 478                 free_irq(dev->irq, dev);
 479                 dev->irq = 0;
 480         }
 481         if (dev->iobase && dev->iolen) {
 482                 release_region(dev->iobase, dev->iolen);
 483                 dev->iobase = 0;
 484                 dev->iolen = 0;
 485         }
 486 }
 487 EXPORT_SYMBOL_GPL(comedi_legacy_detach);
 488
 489 int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 490 {
 491         struct comedi_driver *driv;
 492         int ret;
 493
 494         if (dev->attached)
 495                 return -EBUSY;
 496
 497         mutex_lock(&comedi_drivers_list_lock);
 498         for (driv = comedi_drivers; driv; driv = driv->next) {
 499                 if (!try_module_get(driv->module))
 500                         continue;
 501                 if (driv->num_names) {
 502                         dev->board_ptr = comedi_recognize(driv, it->board_name);
 503                         if (dev->board_ptr)
 504                                 break;
 505                 } else if (strcmp(driv->driver_name, it->board_name) == 0)
 506                         break;
 507                 module_put(driv->module);
 508         }
 509         if (driv == NULL) {
 510                 /*  recognize has failed if we get here */
 511                 /*  report valid board names before returning error */
 512                 for (driv = comedi_drivers; driv; driv = driv->next) {
 513                         if (!try_module_get(driv->module))
 514                                 continue;
 515                         comedi_report_boards(driv);
 516                         module_put(driv->module);
 517                 }
 518                 ret = -EIO;
 519                 goto out;
 520         }
 521         if (driv->attach == NULL) {
 522                 /* driver does not support manual configuration */
 523                 dev_warn(dev->class_dev,
 524                          "driver '%s' does not support attach using comedi_config\n",
 525                          driv->driver_name);
 526                 module_put(driv->module);
 527                 ret = -ENOSYS;
 528                 goto out;
 529         }
 530         /* initialize dev->driver here so
 531          * comedi_error() can be called from attach */
 532         dev->driver = driv;
 533         dev->board_name = dev->board_ptr ? *(const char **)dev->board_ptr
 534                                          : dev->driver->driver_name;
 535         ret = driv->attach(dev, it);
 536         if (ret >= 0)
 537                 ret = comedi_device_postconfig(dev);
 538         if (ret < 0) {
 539                 comedi_device_detach(dev);
 540                 module_put(driv->module);
 541         }
 542         /* On success, the driver module count has been incremented. */
 543 out:
 544         mutex_unlock(&comedi_drivers_list_lock);
 545         return ret;
 546 }
 547
 548 int comedi_auto_config(struct device *hardware_device,
 549                        struct comedi_driver *driver, unsigned long context)
 550 {
 551         struct comedi_device *dev;
 552         int ret;
 553
 554         if (!hardware_device) {
 555                 pr_warn("BUG! comedi_auto_config called with NULL hardware_device\n");
 556                 return -EINVAL;
 557         }
 558         if (!driver) {
 559                 dev_warn(hardware_device,
 560                          "BUG! comedi_auto_config called with NULL comedi driver\n");
 561                 return -EINVAL;
 562         }
 563
 564         if (!driver->auto_attach) {
 565                 dev_warn(hardware_device,
 566                          "BUG! comedi driver '%s' has no auto_attach handler\n",
 567                          driver->driver_name);
 568                 return -EINVAL;
 569         }
 570
 571         dev = comedi_alloc_board_minor(hardware_device);
 572         if (IS_ERR(dev))
 573                 return PTR_ERR(dev);
 574         /* Note: comedi_alloc_board_minor() locked dev->mutex. */
 575
 576         dev->driver = driver;
 577         dev->board_name = dev->driver->driver_name;
 578         ret = driver->auto_attach(dev, context);
 579         if (ret >= 0)
 580                 ret = comedi_device_postconfig(dev);
 581         if (ret < 0)
 582                 comedi_device_detach(dev);
 583         mutex_unlock(&dev->mutex);
 584
 585         if (ret < 0)
 586                 comedi_release_hardware_device(hardware_device);
 587         return ret;
 588 }
 589 EXPORT_SYMBOL_GPL(comedi_auto_config);
 590
 591 void comedi_auto_unconfig(struct device *hardware_device)
 592 {
 593         if (hardware_device == NULL)
 594                 return;
 595         comedi_release_hardware_device(hardware_device);
 596 }
 597 EXPORT_SYMBOL_GPL(comedi_auto_unconfig);
 598
 599 int comedi_driver_register(struct comedi_driver *driver)
 600 {
 601         mutex_lock(&comedi_drivers_list_lock);
 602         driver->next = comedi_drivers;
 603         comedi_drivers = driver;
 604         mutex_unlock(&comedi_drivers_list_lock);
 605
 606         return 0;
 607 }
 608 EXPORT_SYMBOL_GPL(comedi_driver_register);
 609
 610 void comedi_driver_unregister(struct comedi_driver *driver)
 611 {
 612         struct comedi_driver *prev;
 613         int i;
 614
 615         /* unlink the driver */
 616         mutex_lock(&comedi_drivers_list_lock);
 617         if (comedi_drivers == driver) {
 618                 comedi_drivers = driver->next;
 619         } else {
 620                 for (prev = comedi_drivers; prev->next; prev = prev->next) {
 621                         if (prev->next == driver) {
 622                                 prev->next = driver->next;
 623                                 break;
 624                         }
 625                 }
 626         }
 627         mutex_unlock(&comedi_drivers_list_lock);
 628
 629         /* check for devices using this driver */
 630         for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
 631                 struct comedi_device *dev = comedi_dev_from_minor(i);
 632
 633                 if (!dev)
 634                         continue;
 635
 636                 mutex_lock(&dev->mutex);
 637                 if (dev->attached && dev->driver == driver) {
 638                         if (dev->use_count)
 639                                 dev_warn(dev->class_dev,
 640                                          "BUG! detaching device with use_count=%d\n",
 641                                          dev->use_count);
 642                         comedi_device_detach(dev);
 643                 }
 644                 mutex_unlock(&dev->mutex);
 645         }
 646 }
 647 EXPORT_SYMBOL_GPL(comedi_driver_unregister);