drivers.c revision f08e0ac59a93db2d8abc7000e2647164104524c6
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 44struct comedi_driver *comedi_drivers; 45 46int 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} 55EXPORT_SYMBOL_GPL(comedi_set_hw_dev); 56 57static void comedi_clear_hw_dev(struct comedi_device *dev) 58{ 59 put_device(dev->hw_dev); 60 dev->hw_dev = NULL; 61} 62 63int 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} 87EXPORT_SYMBOL_GPL(comedi_alloc_subdevices); 88 89static 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 122static 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 133void comedi_device_detach(struct comedi_device *dev) 134{ 135 if (!dev->attached) 136 return; 137 __comedi_device_detach(dev); 138} 139 140static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s) 141{ 142 return -EINVAL; 143} 144 145int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s, 146 struct comedi_insn *insn, unsigned int *data) 147{ 148 return -EINVAL; 149} 150 151static 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 188static 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 234static 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 */ 281static 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 */ 324static 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 338static 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 356int 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 406int 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 (!hardware_device) { 414 pr_warn("BUG! comedi_auto_config called with NULL hardware_device\n"); 415 return -EINVAL; 416 } 417 if (!driver) { 418 dev_warn(hardware_device, 419 "BUG! comedi_auto_config called with NULL comedi driver\n"); 420 return -EINVAL; 421 } 422 423 if (!driver->auto_attach) { 424 dev_warn(hardware_device, 425 "BUG! comedi driver '%s' has no auto_attach handler\n", 426 driver->driver_name); 427 return -EINVAL; 428 } 429 430 minor = comedi_alloc_board_minor(hardware_device); 431 if (minor < 0) 432 return minor; 433 434 comedi_dev = comedi_dev_from_minor(minor); 435 436 mutex_lock(&comedi_dev->mutex); 437 if (comedi_dev->attached) 438 ret = -EBUSY; 439 else if (!try_module_get(driver->module)) 440 ret = -EIO; 441 else { 442 comedi_set_hw_dev(comedi_dev, hardware_device); 443 comedi_dev->driver = driver; 444 ret = driver->auto_attach(comedi_dev, context); 445 if (ret < 0) { 446 module_put(driver->module); 447 __comedi_device_detach(comedi_dev); 448 } else { 449 ret = comedi_device_postconfig(comedi_dev); 450 } 451 } 452 mutex_unlock(&comedi_dev->mutex); 453 454 if (ret < 0) 455 comedi_free_board_minor(minor); 456 return ret; 457} 458EXPORT_SYMBOL_GPL(comedi_auto_config); 459 460void comedi_auto_unconfig(struct device *hardware_device) 461{ 462 int minor; 463 464 if (hardware_device == NULL) 465 return; 466 minor = comedi_find_board_minor(hardware_device); 467 if (minor < 0) 468 return; 469 comedi_free_board_minor(minor); 470} 471EXPORT_SYMBOL_GPL(comedi_auto_unconfig); 472 473int comedi_driver_register(struct comedi_driver *driver) 474{ 475 driver->next = comedi_drivers; 476 comedi_drivers = driver; 477 478 return 0; 479} 480EXPORT_SYMBOL(comedi_driver_register); 481 482int comedi_driver_unregister(struct comedi_driver *driver) 483{ 484 struct comedi_driver *prev; 485 int i; 486 487 /* check for devices using this driver */ 488 for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) { 489 struct comedi_device *dev = comedi_dev_from_minor(i); 490 491 if (!dev) 492 continue; 493 494 mutex_lock(&dev->mutex); 495 if (dev->attached && dev->driver == driver) { 496 if (dev->use_count) 497 dev_warn(dev->class_dev, 498 "BUG! detaching device with use_count=%d\n", 499 dev->use_count); 500 comedi_device_detach(dev); 501 } 502 mutex_unlock(&dev->mutex); 503 } 504 505 if (comedi_drivers == driver) { 506 comedi_drivers = driver->next; 507 return 0; 508 } 509 510 for (prev = comedi_drivers; prev->next; prev = prev->next) { 511 if (prev->next == driver) { 512 prev->next = driver->next; 513 return 0; 514 } 515 } 516 return -EINVAL; 517} 518EXPORT_SYMBOL(comedi_driver_unregister); 519