drivers/misc/mei/bus.c

   1 /*
   2  * Intel Management Engine Interface (Intel MEI) Linux driver
   3  * Copyright (c) 2012-2013, Intel Corporation.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms and conditions of the GNU General Public License,
   7  * version 2, as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/device.h>
  18 #include <linux/kernel.h>
  19 #include <linux/sched.h>
  20 #include <linux/init.h>
  21 #include <linux/errno.h>
  22 #include <linux/slab.h>
  23 #include <linux/mutex.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/mei_cl_bus.h>
  26
  27 #include "mei_dev.h"
  28 #include "client.h"
  29
  30 #define to_mei_cl_driver(d) container_of(d, struct mei_cl_driver, driver)
  31 #define to_mei_cl_device(d) container_of(d, struct mei_cl_device, dev)
  32
  33 static int mei_cl_device_match(struct device *dev, struct device_driver *drv)
  34 {
  35         struct mei_cl_device *device = to_mei_cl_device(dev);
  36         struct mei_cl_driver *driver = to_mei_cl_driver(drv);
  37         const struct mei_cl_device_id *id;
  38
  39         if (!device)
  40                 return 0;
  41
  42         if (!driver || !driver->id_table)
  43                 return 0;
  44
  45         id = driver->id_table;
  46
  47         while (id->name[0]) {
  48                 if (!strncmp(dev_name(dev), id->name, sizeof(id->name)))
  49                         return 1;
  50
  51                 id++;
  52         }
  53
  54         return 0;
  55 }
  56
  57 static int mei_cl_device_probe(struct device *dev)
  58 {
  59         struct mei_cl_device *device = to_mei_cl_device(dev);
  60         struct mei_cl_driver *driver;
  61         struct mei_cl_device_id id;
  62
  63         if (!device)
  64                 return 0;
  65
  66         driver = to_mei_cl_driver(dev->driver);
  67         if (!driver || !driver->probe)
  68                 return -ENODEV;
  69
  70         dev_dbg(dev, "Device probe\n");
  71
  72         strlcpy(id.name, dev_name(dev), sizeof(id.name));
  73
  74         return driver->probe(device, &id);
  75 }
  76
  77 static int mei_cl_device_remove(struct device *dev)
  78 {
  79         struct mei_cl_device *device = to_mei_cl_device(dev);
  80         struct mei_cl_driver *driver;
  81
  82         if (!device || !dev->driver)
  83                 return 0;
  84
  85         if (device->event_cb) {
  86                 device->event_cb = NULL;
  87                 cancel_work_sync(&device->event_work);
  88         }
  89
  90         driver = to_mei_cl_driver(dev->driver);
  91         if (!driver->remove) {
  92                 dev->driver = NULL;
  93
  94                 return 0;
  95         }
  96
  97         return driver->remove(device);
  98 }
  99
 100 static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
 101                              char *buf)
 102 {
 103         int len;
 104
 105         len = snprintf(buf, PAGE_SIZE, "mei:%s\n", dev_name(dev));
 106
 107         return (len >= PAGE_SIZE) ? (PAGE_SIZE - 1) : len;
 108 }
 109 static DEVICE_ATTR_RO(modalias);
 110
 111 static struct attribute *mei_cl_dev_attrs[] = {
 112         &dev_attr_modalias.attr,
 113         NULL,
 114 };
 115 ATTRIBUTE_GROUPS(mei_cl_dev);
 116
 117 static int mei_cl_uevent(struct device *dev, struct kobj_uevent_env *env)
 118 {
 119         if (add_uevent_var(env, "MODALIAS=mei:%s", dev_name(dev)))
 120                 return -ENOMEM;
 121
 122         return 0;
 123 }
 124
 125 static struct bus_type mei_cl_bus_type = {
 126         .name           = "mei",
 127         .dev_groups     = mei_cl_dev_groups,
 128         .match          = mei_cl_device_match,
 129         .probe          = mei_cl_device_probe,
 130         .remove         = mei_cl_device_remove,
 131         .uevent         = mei_cl_uevent,
 132 };
 133
 134 static void mei_cl_dev_release(struct device *dev)
 135 {
 136         kfree(to_mei_cl_device(dev));
 137 }
 138
 139 static struct device_type mei_cl_device_type = {
 140         .release        = mei_cl_dev_release,
 141 };
 142
 143 struct mei_cl *mei_cl_bus_find_cl_by_uuid(struct mei_device *dev,
 144                                                 uuid_le uuid)
 145 {
 146         struct mei_cl *cl;
 147
 148         list_for_each_entry(cl, &dev->device_list, device_link) {
 149                 if (!uuid_le_cmp(uuid, cl->cl_uuid))
 150                         return cl;
 151         }
 152
 153         return NULL;
 154 }
 155 struct mei_cl_device *mei_cl_add_device(struct mei_device *dev,
 156                                         uuid_le uuid, char *name,
 157                                         struct mei_cl_ops *ops)
 158 {
 159         struct mei_cl_device *device;
 160         struct mei_cl *cl;
 161         int status;
 162
 163         cl = mei_cl_bus_find_cl_by_uuid(dev, uuid);
 164         if (cl == NULL)
 165                 return NULL;
 166
 167         device = kzalloc(sizeof(struct mei_cl_device), GFP_KERNEL);
 168         if (!device)
 169                 return NULL;
 170
 171         device->cl = cl;
 172         device->ops = ops;
 173
 174         device->dev.parent = dev->dev;
 175         device->dev.bus = &mei_cl_bus_type;
 176         device->dev.type = &mei_cl_device_type;
 177
 178         dev_set_name(&device->dev, "%s", name);
 179
 180         status = device_register(&device->dev);
 181         if (status) {
 182                 dev_err(dev->dev, "Failed to register MEI device\n");
 183                 kfree(device);
 184                 return NULL;
 185         }
 186
 187         cl->device = device;
 188
 189         dev_dbg(&device->dev, "client %s registered\n", name);
 190
 191         return device;
 192 }
 193 EXPORT_SYMBOL_GPL(mei_cl_add_device);
 194
 195 void mei_cl_remove_device(struct mei_cl_device *device)
 196 {
 197         device_unregister(&device->dev);
 198 }
 199 EXPORT_SYMBOL_GPL(mei_cl_remove_device);
 200
 201 int __mei_cl_driver_register(struct mei_cl_driver *driver, struct module *owner)
 202 {
 203         int err;
 204
 205         driver->driver.name = driver->name;
 206         driver->driver.owner = owner;
 207         driver->driver.bus = &mei_cl_bus_type;
 208
 209         err = driver_register(&driver->driver);
 210         if (err)
 211                 return err;
 212
 213         pr_debug("mei: driver [%s] registered\n", driver->driver.name);
 214
 215         return 0;
 216 }
 217 EXPORT_SYMBOL_GPL(__mei_cl_driver_register);
 218
 219 void mei_cl_driver_unregister(struct mei_cl_driver *driver)
 220 {
 221         driver_unregister(&driver->driver);
 222
 223         pr_debug("mei: driver [%s] unregistered\n", driver->driver.name);
 224 }
 225 EXPORT_SYMBOL_GPL(mei_cl_driver_unregister);
 226
 227 static ssize_t ___mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length,
 228                         bool blocking)
 229 {
 230         struct mei_device *dev;
 231         struct mei_me_client *me_cl = NULL;
 232         struct mei_cl_cb *cb = NULL;
 233         ssize_t rets;
 234
 235         if (WARN_ON(!cl || !cl->dev))
 236                 return -ENODEV;
 237
 238         dev = cl->dev;
 239
 240         mutex_lock(&dev->device_lock);
 241         if (cl->state != MEI_FILE_CONNECTED) {
 242                 rets = -ENODEV;
 243                 goto out;
 244         }
 245
 246         /* Check if we have an ME client device */
 247         me_cl = mei_me_cl_by_uuid_id(dev, &cl->cl_uuid, cl->me_client_id);
 248         if (!me_cl) {
 249                 rets = -ENOTTY;
 250                 goto out;
 251         }
 252
 253         if (length > me_cl->props.max_msg_length) {
 254                 rets = -EFBIG;
 255                 goto out;
 256         }
 257
 258         cb = mei_io_cb_init(cl, NULL);
 259         if (!cb) {
 260                 rets = -ENOMEM;
 261                 goto out;
 262         }
 263
 264         rets = mei_io_cb_alloc_req_buf(cb, length);
 265         if (rets < 0)
 266                 goto out;
 267
 268         memcpy(cb->request_buffer.data, buf, length);
 269
 270         rets = mei_cl_write(cl, cb, blocking);
 271
 272 out:
 273         mei_me_cl_put(me_cl);
 274         mutex_unlock(&dev->device_lock);
 275         if (rets < 0)
 276                 mei_io_cb_free(cb);
 277
 278         return rets;
 279 }
 280
 281 ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length)
 282 {
 283         struct mei_device *dev;
 284         struct mei_cl_cb *cb;
 285         size_t r_length;
 286         ssize_t rets;
 287
 288         if (WARN_ON(!cl || !cl->dev))
 289                 return -ENODEV;
 290
 291         dev = cl->dev;
 292
 293         mutex_lock(&dev->device_lock);
 294
 295         if (!cl->read_cb) {
 296                 rets = mei_cl_read_start(cl, length);
 297                 if (rets < 0)
 298                         goto out;
 299         }
 300
 301         if (cl->reading_state != MEI_READ_COMPLETE &&
 302             !waitqueue_active(&cl->rx_wait)) {
 303
 304                 mutex_unlock(&dev->device_lock);
 305
 306                 if (wait_event_interruptible(cl->rx_wait,
 307                                 cl->reading_state == MEI_READ_COMPLETE  ||
 308                                 mei_cl_is_transitioning(cl))) {
 309
 310                         if (signal_pending(current))
 311                                 return -EINTR;
 312                         return -ERESTARTSYS;
 313                 }
 314
 315                 mutex_lock(&dev->device_lock);
 316         }
 317
 318         cb = cl->read_cb;
 319
 320         if (cl->reading_state != MEI_READ_COMPLETE) {
 321                 rets = 0;
 322                 goto out;
 323         }
 324
 325         if (cb->status) {
 326                 rets = cb->status;
 327                 goto free;
 328         }
 329
 330         r_length = min_t(size_t, length, cb->buf_idx);
 331         memcpy(buf, cb->response_buffer.data, r_length);
 332         rets = r_length;
 333
 334 free:
 335         mei_io_cb_free(cb);
 336         cl->reading_state = MEI_IDLE;
 337         cl->read_cb = NULL;
 338
 339 out:
 340         mutex_unlock(&dev->device_lock);
 341
 342         return rets;
 343 }
 344
 345 inline ssize_t __mei_cl_async_send(struct mei_cl *cl, u8 *buf, size_t length)
 346 {
 347         return ___mei_cl_send(cl, buf, length, 0);
 348 }
 349
 350 inline ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length)
 351 {
 352         return ___mei_cl_send(cl, buf, length, 1);
 353 }
 354
 355 ssize_t mei_cl_send(struct mei_cl_device *device, u8 *buf, size_t length)
 356 {
 357         struct mei_cl *cl = device->cl;
 358
 359         if (cl == NULL)
 360                 return -ENODEV;
 361
 362         if (device->ops && device->ops->send)
 363                 return device->ops->send(device, buf, length);
 364
 365         return __mei_cl_send(cl, buf, length);
 366 }
 367 EXPORT_SYMBOL_GPL(mei_cl_send);
 368
 369 ssize_t mei_cl_recv(struct mei_cl_device *device, u8 *buf, size_t length)
 370 {
 371         struct mei_cl *cl =  device->cl;
 372
 373         if (cl == NULL)
 374                 return -ENODEV;
 375
 376         if (device->ops && device->ops->recv)
 377                 return device->ops->recv(device, buf, length);
 378
 379         return __mei_cl_recv(cl, buf, length);
 380 }
 381 EXPORT_SYMBOL_GPL(mei_cl_recv);
 382
 383 static void mei_bus_event_work(struct work_struct *work)
 384 {
 385         struct mei_cl_device *device;
 386
 387         device = container_of(work, struct mei_cl_device, event_work);
 388
 389         if (device->event_cb)
 390                 device->event_cb(device, device->events, device->event_context);
 391
 392         device->events = 0;
 393
 394         /* Prepare for the next read */
 395         mei_cl_read_start(device->cl, 0);
 396 }
 397
 398 int mei_cl_register_event_cb(struct mei_cl_device *device,
 399                           mei_cl_event_cb_t event_cb, void *context)
 400 {
 401         if (device->event_cb)
 402                 return -EALREADY;
 403
 404         device->events = 0;
 405         device->event_cb = event_cb;
 406         device->event_context = context;
 407         INIT_WORK(&device->event_work, mei_bus_event_work);
 408
 409         mei_cl_read_start(device->cl, 0);
 410
 411         return 0;
 412 }
 413 EXPORT_SYMBOL_GPL(mei_cl_register_event_cb);
 414
 415 void *mei_cl_get_drvdata(const struct mei_cl_device *device)
 416 {
 417         return dev_get_drvdata(&device->dev);
 418 }
 419 EXPORT_SYMBOL_GPL(mei_cl_get_drvdata);
 420
 421 void mei_cl_set_drvdata(struct mei_cl_device *device, void *data)
 422 {
 423         dev_set_drvdata(&device->dev, data);
 424 }
 425 EXPORT_SYMBOL_GPL(mei_cl_set_drvdata);
 426
 427 int mei_cl_enable_device(struct mei_cl_device *device)
 428 {
 429         int err;
 430         struct mei_device *dev;
 431         struct mei_cl *cl = device->cl;
 432
 433         if (cl == NULL)
 434                 return -ENODEV;
 435
 436         dev = cl->dev;
 437
 438         mutex_lock(&dev->device_lock);
 439
 440         err = mei_cl_connect(cl, NULL);
 441         if (err < 0) {
 442                 mutex_unlock(&dev->device_lock);
 443                 dev_err(dev->dev, "Could not connect to the ME client");
 444
 445                 return err;
 446         }
 447
 448         mutex_unlock(&dev->device_lock);
 449
 450         if (device->event_cb && !cl->read_cb)
 451                 mei_cl_read_start(device->cl, 0);
 452
 453         if (!device->ops || !device->ops->enable)
 454                 return 0;
 455
 456         return device->ops->enable(device);
 457 }
 458 EXPORT_SYMBOL_GPL(mei_cl_enable_device);
 459
 460 int mei_cl_disable_device(struct mei_cl_device *device)
 461 {
 462         int err;
 463         struct mei_device *dev;
 464         struct mei_cl *cl = device->cl;
 465
 466         if (cl == NULL)
 467                 return -ENODEV;
 468
 469         dev = cl->dev;
 470
 471         mutex_lock(&dev->device_lock);
 472
 473         if (cl->state != MEI_FILE_CONNECTED) {
 474                 mutex_unlock(&dev->device_lock);
 475                 dev_err(dev->dev, "Already disconnected");
 476
 477                 return 0;
 478         }
 479
 480         cl->state = MEI_FILE_DISCONNECTING;
 481
 482         err = mei_cl_disconnect(cl);
 483         if (err < 0) {
 484                 mutex_unlock(&dev->device_lock);
 485                 dev_err(dev->dev,
 486                         "Could not disconnect from the ME client");
 487
 488                 return err;
 489         }
 490
 491         /* Flush queues and remove any pending read */
 492         mei_cl_flush_queues(cl);
 493
 494         if (cl->read_cb) {
 495                 struct mei_cl_cb *cb = NULL;
 496
 497                 cb = mei_cl_find_read_cb(cl);
 498                 /* Remove entry from read list */
 499                 if (cb)
 500                         list_del(&cb->list);
 501
 502                 cb = cl->read_cb;
 503                 cl->read_cb = NULL;
 504
 505                 if (cb) {
 506                         mei_io_cb_free(cb);
 507                         cb = NULL;
 508                 }
 509         }
 510
 511         device->event_cb = NULL;
 512
 513         mutex_unlock(&dev->device_lock);
 514
 515         if (!device->ops || !device->ops->disable)
 516                 return 0;
 517
 518         return device->ops->disable(device);
 519 }
 520 EXPORT_SYMBOL_GPL(mei_cl_disable_device);
 521
 522 void mei_cl_bus_rx_event(struct mei_cl *cl)
 523 {
 524         struct mei_cl_device *device = cl->device;
 525
 526         if (!device || !device->event_cb)
 527                 return;
 528
 529         set_bit(MEI_CL_EVENT_RX, &device->events);
 530
 531         schedule_work(&device->event_work);
 532 }
 533
 534 void mei_cl_bus_remove_devices(struct mei_device *dev)
 535 {
 536         struct mei_cl *cl, *next;
 537
 538         mutex_lock(&dev->device_lock);
 539         list_for_each_entry_safe(cl, next, &dev->device_list, device_link) {
 540                 if (cl->device)
 541                         mei_cl_remove_device(cl->device);
 542
 543                 list_del(&cl->device_link);
 544                 mei_cl_unlink(cl);
 545                 kfree(cl);
 546         }
 547         mutex_unlock(&dev->device_lock);
 548 }
 549
 550 int __init mei_cl_bus_init(void)
 551 {
 552         return bus_register(&mei_cl_bus_type);
 553 }
 554
 555 void __exit mei_cl_bus_exit(void)
 556 {
 557         bus_unregister(&mei_cl_bus_type);
 558 }