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