drivers.c revision d569541e537e13136fc775a902cda06f4c48bbe1
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 41struct comedi_driver *comedi_drivers; 42 43int 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} 52EXPORT_SYMBOL_GPL(comedi_set_hw_dev); 53 54static void comedi_clear_hw_dev(struct comedi_device *dev) 55{ 56 put_device(dev->hw_dev); 57 dev->hw_dev = NULL; 58} 59 60int 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} 84EXPORT_SYMBOL_GPL(comedi_alloc_subdevices); 85 86void comedi_spriv_free(struct comedi_device *dev, int subdev_num) 87{ 88 struct comedi_subdevice *s; 89 90 if (dev->subdevices && subdev_num < dev->n_subdevices) { 91 s = &dev->subdevices[subdev_num]; 92 kfree(s->private); 93 s->private = NULL; 94 } 95} 96EXPORT_SYMBOL_GPL(comedi_spriv_free); 97 98static 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 comedi_free_subdevice_minor(s); 107 if (s->async) { 108 comedi_buf_alloc(dev, s, 0); 109 kfree(s->async); 110 } 111 } 112 kfree(dev->subdevices); 113 dev->subdevices = NULL; 114 dev->n_subdevices = 0; 115 } 116 kfree(dev->private); 117 dev->private = NULL; 118 dev->driver = NULL; 119 dev->board_name = NULL; 120 dev->board_ptr = NULL; 121 dev->iobase = 0; 122 dev->iolen = 0; 123 dev->ioenabled = false; 124 dev->irq = 0; 125 dev->read_subdev = NULL; 126 dev->write_subdev = NULL; 127 dev->open = NULL; 128 dev->close = NULL; 129 comedi_clear_hw_dev(dev); 130} 131 132void comedi_device_detach(struct comedi_device *dev) 133{ 134 dev->attached = false; 135 if (dev->driver) 136 dev->driver->detach(dev); 137 cleanup_device(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 */ 280static int comedi_device_postconfig(struct comedi_device *dev) 281{ 282 int ret; 283 284 ret = __comedi_device_postconfig(dev); 285 if (ret < 0) 286 return ret; 287 smp_wmb(); 288 dev->attached = true; 289 return 0; 290} 291 292/* 293 * Generic recognize function for drivers that register their supported 294 * board names. 295 * 296 * 'driv->board_name' points to a 'const char *' member within the 297 * zeroth element of an array of some private board information 298 * structure, say 'struct foo_board' containing a member 'const char 299 * *board_name' that is initialized to point to a board name string that 300 * is one of the candidates matched against this function's 'name' 301 * parameter. 302 * 303 * 'driv->offset' is the size of the private board information 304 * structure, say 'sizeof(struct foo_board)', and 'driv->num_names' is 305 * the length of the array of private board information structures. 306 * 307 * If one of the board names in the array of private board information 308 * structures matches the name supplied to this function, the function 309 * returns a pointer to the pointer to the board name, otherwise it 310 * returns NULL. The return value ends up in the 'board_ptr' member of 311 * a 'struct comedi_device' that the low-level comedi driver's 312 * 'attach()' hook can convert to a point to a particular element of its 313 * array of private board information structures by subtracting the 314 * offset of the member that points to the board name. (No subtraction 315 * is required if the board name pointer is the first member of the 316 * private board information structure, which is generally the case.) 317 */ 318static void *comedi_recognize(struct comedi_driver *driv, const char *name) 319{ 320 char **name_ptr = (char **)driv->board_name; 321 int i; 322 323 for (i = 0; i < driv->num_names; i++) { 324 if (strcmp(*name_ptr, name) == 0) 325 return name_ptr; 326 name_ptr = (void *)name_ptr + driv->offset; 327 } 328 329 return NULL; 330} 331 332static void comedi_report_boards(struct comedi_driver *driv) 333{ 334 unsigned int i; 335 const char *const *name_ptr; 336 337 pr_info("comedi: valid board names for %s driver are:\n", 338 driv->driver_name); 339 340 name_ptr = driv->board_name; 341 for (i = 0; i < driv->num_names; i++) { 342 pr_info(" %s\n", *name_ptr); 343 name_ptr = (const char **)((char *)name_ptr + driv->offset); 344 } 345 346 if (driv->num_names == 0) 347 pr_info(" %s\n", driv->driver_name); 348} 349 350/** 351 * comedi_load_firmware() - Request and load firmware for a device. 352 * @dev: comedi_device struct 353 * @hw_device: device struct for the comedi_device 354 * @name: the name of the firmware image 355 * @cb: callback to the upload the firmware image 356 * @context: private context from the driver 357 */ 358int comedi_load_firmware(struct comedi_device *dev, 359 struct device *device, 360 const char *name, 361 int (*cb)(struct comedi_device *dev, 362 const u8 *data, size_t size, 363 unsigned long context), 364 unsigned long context) 365{ 366 const struct firmware *fw; 367 int ret; 368 369 if (!cb) 370 return -EINVAL; 371 372 ret = request_firmware(&fw, name, device); 373 if (ret == 0) { 374 ret = cb(dev, fw->data, fw->size, context); 375 release_firmware(fw); 376 } 377 378 return ret; 379} 380EXPORT_SYMBOL_GPL(comedi_load_firmware); 381 382/** 383 * __comedi_request_region() - Request an I/O reqion for a legacy driver. 384 * @dev: comedi_device struct 385 * @start: base address of the I/O reqion 386 * @len: length of the I/O region 387 */ 388int __comedi_request_region(struct comedi_device *dev, 389 unsigned long start, unsigned long len) 390{ 391 if (!start) { 392 dev_warn(dev->class_dev, 393 "%s: a I/O base address must be specified\n", 394 dev->board_name); 395 return -EINVAL; 396 } 397 398 if (!request_region(start, len, dev->board_name)) { 399 dev_warn(dev->class_dev, "%s: I/O port conflict (%#lx,%lu)\n", 400 dev->board_name, start, len); 401 return -EIO; 402 } 403 404 return 0; 405} 406EXPORT_SYMBOL_GPL(__comedi_request_region); 407 408/** 409 * comedi_request_region() - Request an I/O reqion for a legacy driver. 410 * @dev: comedi_device struct 411 * @start: base address of the I/O reqion 412 * @len: length of the I/O region 413 */ 414int comedi_request_region(struct comedi_device *dev, 415 unsigned long start, unsigned long len) 416{ 417 int ret; 418 419 ret = __comedi_request_region(dev, start, len); 420 if (ret == 0) { 421 dev->iobase = start; 422 dev->iolen = len; 423 } 424 425 return ret; 426} 427EXPORT_SYMBOL_GPL(comedi_request_region); 428 429/** 430 * comedi_legacy_detach() - A generic (*detach) function for legacy drivers. 431 * @dev: comedi_device struct 432 */ 433void comedi_legacy_detach(struct comedi_device *dev) 434{ 435 if (dev->irq) { 436 free_irq(dev->irq, dev); 437 dev->irq = 0; 438 } 439 if (dev->iobase && dev->iolen) { 440 release_region(dev->iobase, dev->iolen); 441 dev->iobase = 0; 442 dev->iolen = 0; 443 } 444} 445EXPORT_SYMBOL_GPL(comedi_legacy_detach); 446 447int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it) 448{ 449 struct comedi_driver *driv; 450 int ret; 451 452 if (dev->attached) 453 return -EBUSY; 454 455 for (driv = comedi_drivers; driv; driv = driv->next) { 456 if (!try_module_get(driv->module)) 457 continue; 458 if (driv->num_names) { 459 dev->board_ptr = comedi_recognize(driv, it->board_name); 460 if (dev->board_ptr) 461 break; 462 } else if (strcmp(driv->driver_name, it->board_name) == 0) 463 break; 464 module_put(driv->module); 465 } 466 if (driv == NULL) { 467 /* recognize has failed if we get here */ 468 /* report valid board names before returning error */ 469 for (driv = comedi_drivers; driv; driv = driv->next) { 470 if (!try_module_get(driv->module)) 471 continue; 472 comedi_report_boards(driv); 473 module_put(driv->module); 474 } 475 return -EIO; 476 } 477 if (driv->attach == NULL) { 478 /* driver does not support manual configuration */ 479 dev_warn(dev->class_dev, 480 "driver '%s' does not support attach using comedi_config\n", 481 driv->driver_name); 482 module_put(driv->module); 483 return -ENOSYS; 484 } 485 /* initialize dev->driver here so 486 * comedi_error() can be called from attach */ 487 dev->driver = driv; 488 dev->board_name = dev->board_ptr ? *(const char **)dev->board_ptr 489 : dev->driver->driver_name; 490 ret = driv->attach(dev, it); 491 if (ret >= 0) 492 ret = comedi_device_postconfig(dev); 493 if (ret < 0) { 494 comedi_device_detach(dev); 495 module_put(dev->driver->module); 496 } 497 /* On success, the driver module count has been incremented. */ 498 return ret; 499} 500 501int comedi_auto_config(struct device *hardware_device, 502 struct comedi_driver *driver, unsigned long context) 503{ 504 struct comedi_device *dev; 505 int ret; 506 507 if (!hardware_device) { 508 pr_warn("BUG! comedi_auto_config called with NULL hardware_device\n"); 509 return -EINVAL; 510 } 511 if (!driver) { 512 dev_warn(hardware_device, 513 "BUG! comedi_auto_config called with NULL comedi driver\n"); 514 return -EINVAL; 515 } 516 517 if (!driver->auto_attach) { 518 dev_warn(hardware_device, 519 "BUG! comedi driver '%s' has no auto_attach handler\n", 520 driver->driver_name); 521 return -EINVAL; 522 } 523 524 dev = comedi_alloc_board_minor(hardware_device); 525 if (IS_ERR(dev)) 526 return PTR_ERR(dev); 527 /* Note: comedi_alloc_board_minor() locked dev->mutex. */ 528 529 dev->driver = driver; 530 dev->board_name = dev->driver->driver_name; 531 ret = driver->auto_attach(dev, context); 532 if (ret >= 0) 533 ret = comedi_device_postconfig(dev); 534 if (ret < 0) 535 comedi_device_detach(dev); 536 mutex_unlock(&dev->mutex); 537 538 if (ret < 0) 539 comedi_release_hardware_device(hardware_device); 540 return ret; 541} 542EXPORT_SYMBOL_GPL(comedi_auto_config); 543 544void comedi_auto_unconfig(struct device *hardware_device) 545{ 546 if (hardware_device == NULL) 547 return; 548 comedi_release_hardware_device(hardware_device); 549} 550EXPORT_SYMBOL_GPL(comedi_auto_unconfig); 551 552int comedi_driver_register(struct comedi_driver *driver) 553{ 554 driver->next = comedi_drivers; 555 comedi_drivers = driver; 556 557 return 0; 558} 559EXPORT_SYMBOL_GPL(comedi_driver_register); 560 561int comedi_driver_unregister(struct comedi_driver *driver) 562{ 563 struct comedi_driver *prev; 564 int i; 565 566 /* check for devices using this driver */ 567 for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) { 568 struct comedi_device *dev = comedi_dev_from_minor(i); 569 570 if (!dev) 571 continue; 572 573 mutex_lock(&dev->mutex); 574 if (dev->attached && dev->driver == driver) { 575 if (dev->use_count) 576 dev_warn(dev->class_dev, 577 "BUG! detaching device with use_count=%d\n", 578 dev->use_count); 579 comedi_device_detach(dev); 580 } 581 mutex_unlock(&dev->mutex); 582 } 583 584 if (comedi_drivers == driver) { 585 comedi_drivers = driver->next; 586 return 0; 587 } 588 589 for (prev = comedi_drivers; prev->next; prev = prev->next) { 590 if (prev->next == driver) { 591 prev->next = driver->next; 592 return 0; 593 } 594 } 595 return -EINVAL; 596} 597EXPORT_SYMBOL_GPL(comedi_driver_unregister); 598