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 static struct mei_cl *mei_bus_find_mei_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_bus_find_mei_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 int ___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;
 232         struct mei_cl_cb *cb;
 233         int rets;
 234
 235         if (WARN_ON(!cl || !cl->dev))
 236                 return -ENODEV;
 237
 238         dev = cl->dev;
 239
 240         if (cl->state != MEI_FILE_CONNECTED)
 241                 return -ENODEV;
 242
 243         /* Check if we have an ME client device */
 244         me_cl = mei_me_cl_by_uuid_id(dev, &cl->cl_uuid, cl->me_client_id);
 245         if (!me_cl)
 246                 return -ENOTTY;
 247
 248         if (length > me_cl->props.max_msg_length)
 249                 return -EFBIG;
 250
 251         cb = mei_io_cb_init(cl, NULL);
 252         if (!cb)
 253                 return -ENOMEM;
 254
 255         rets = mei_io_cb_alloc_req_buf(cb, length);
 256         if (rets < 0) {
 257                 mei_io_cb_free(cb);
 258                 return rets;
 259         }
 260
 261         memcpy(cb->request_buffer.data, buf, length);
 262
 263         mutex_lock(&dev->device_lock);
 264
 265         rets = mei_cl_write(cl, cb, blocking);
 266
 267         mutex_unlock(&dev->device_lock);
 268         if (rets < 0)
 269                 mei_io_cb_free(cb);
 270
 271         return rets;
 272 }
 273
 274 int __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length)
 275 {
 276         struct mei_device *dev;
 277         struct mei_cl_cb *cb;
 278         size_t r_length;
 279         int err;
 280
 281         if (WARN_ON(!cl || !cl->dev))
 282                 return -ENODEV;
 283
 284         dev = cl->dev;
 285
 286         mutex_lock(&dev->device_lock);
 287
 288         if (!cl->read_cb) {
 289                 err = mei_cl_read_start(cl, length);
 290                 if (err < 0) {
 291                         mutex_unlock(&dev->device_lock);
 292                         return err;
 293                 }
 294         }
 295
 296         if (cl->reading_state != MEI_READ_COMPLETE &&
 297             !waitqueue_active(&cl->rx_wait)) {
 298
 299                 mutex_unlock(&dev->device_lock);
 300
 301                 if (wait_event_interruptible(cl->rx_wait,
 302                                 cl->reading_state == MEI_READ_COMPLETE  ||
 303                                 mei_cl_is_transitioning(cl))) {
 304
 305                         if (signal_pending(current))
 306                                 return -EINTR;
 307                         return -ERESTARTSYS;
 308                 }
 309
 310                 mutex_lock(&dev->device_lock);
 311         }
 312
 313         cb = cl->read_cb;
 314
 315         if (cl->reading_state != MEI_READ_COMPLETE) {
 316                 r_length = 0;
 317                 goto out;
 318         }
 319
 320         r_length = min_t(size_t, length, cb->buf_idx);
 321
 322         memcpy(buf, cb->response_buffer.data, r_length);
 323
 324         mei_io_cb_free(cb);
 325         cl->reading_state = MEI_IDLE;
 326         cl->read_cb = NULL;
 327
 328 out:
 329         mutex_unlock(&dev->device_lock);
 330
 331         return r_length;
 332 }
 333
 334 inline int __mei_cl_async_send(struct mei_cl *cl, u8 *buf, size_t length)
 335 {
 336         return ___mei_cl_send(cl, buf, length, 0);
 337 }
 338
 339 inline int __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length)
 340 {
 341         return ___mei_cl_send(cl, buf, length, 1);
 342 }
 343
 344 int mei_cl_send(struct mei_cl_device *device, u8 *buf, size_t length)
 345 {
 346         struct mei_cl *cl = device->cl;
 347
 348         if (cl == NULL)
 349                 return -ENODEV;
 350
 351         if (device->ops && device->ops->send)
 352                 return device->ops->send(device, buf, length);
 353
 354         return __mei_cl_send(cl, buf, length);
 355 }
 356 EXPORT_SYMBOL_GPL(mei_cl_send);
 357
 358 int mei_cl_recv(struct mei_cl_device *device, u8 *buf, size_t length)
 359 {
 360         struct mei_cl *cl =  device->cl;
 361
 362         if (cl == NULL)
 363                 return -ENODEV;
 364
 365         if (device->ops && device->ops->recv)
 366                 return device->ops->recv(device, buf, length);
 367
 368         return __mei_cl_recv(cl, buf, length);
 369 }
 370 EXPORT_SYMBOL_GPL(mei_cl_recv);
 371
 372 static void mei_bus_event_work(struct work_struct *work)
 373 {
 374         struct mei_cl_device *device;
 375
 376         device = container_of(work, struct mei_cl_device, event_work);
 377
 378         if (device->event_cb)
 379                 device->event_cb(device, device->events, device->event_context);
 380
 381         device->events = 0;
 382
 383         /* Prepare for the next read */
 384         mei_cl_read_start(device->cl, 0);
 385 }
 386
 387 int mei_cl_register_event_cb(struct mei_cl_device *device,
 388                           mei_cl_event_cb_t event_cb, void *context)
 389 {
 390         if (device->event_cb)
 391                 return -EALREADY;
 392
 393         device->events = 0;
 394         device->event_cb = event_cb;
 395         device->event_context = context;
 396         INIT_WORK(&device->event_work, mei_bus_event_work);
 397
 398         mei_cl_read_start(device->cl, 0);
 399
 400         return 0;
 401 }
 402 EXPORT_SYMBOL_GPL(mei_cl_register_event_cb);
 403
 404 void *mei_cl_get_drvdata(const struct mei_cl_device *device)
 405 {
 406         return dev_get_drvdata(&device->dev);
 407 }
 408 EXPORT_SYMBOL_GPL(mei_cl_get_drvdata);
 409
 410 void mei_cl_set_drvdata(struct mei_cl_device *device, void *data)
 411 {
 412         dev_set_drvdata(&device->dev, data);
 413 }
 414 EXPORT_SYMBOL_GPL(mei_cl_set_drvdata);
 415
 416 int mei_cl_enable_device(struct mei_cl_device *device)
 417 {
 418         int err;
 419         struct mei_device *dev;
 420         struct mei_cl *cl = device->cl;
 421
 422         if (cl == NULL)
 423                 return -ENODEV;
 424
 425         dev = cl->dev;
 426
 427         mutex_lock(&dev->device_lock);
 428
 429         err = mei_cl_connect(cl, NULL);
 430         if (err < 0) {
 431                 mutex_unlock(&dev->device_lock);
 432                 dev_err(dev->dev, "Could not connect to the ME client");
 433
 434                 return err;
 435         }
 436
 437         mutex_unlock(&dev->device_lock);
 438
 439         if (device->event_cb && !cl->read_cb)
 440                 mei_cl_read_start(device->cl, 0);
 441
 442         if (!device->ops || !device->ops->enable)
 443                 return 0;
 444
 445         return device->ops->enable(device);
 446 }
 447 EXPORT_SYMBOL_GPL(mei_cl_enable_device);
 448
 449 int mei_cl_disable_device(struct mei_cl_device *device)
 450 {
 451         int err;
 452         struct mei_device *dev;
 453         struct mei_cl *cl = device->cl;
 454
 455         if (cl == NULL)
 456                 return -ENODEV;
 457
 458         dev = cl->dev;
 459
 460         mutex_lock(&dev->device_lock);
 461
 462         if (cl->state != MEI_FILE_CONNECTED) {
 463                 mutex_unlock(&dev->device_lock);
 464                 dev_err(dev->dev, "Already disconnected");
 465
 466                 return 0;
 467         }
 468
 469         cl->state = MEI_FILE_DISCONNECTING;
 470
 471         err = mei_cl_disconnect(cl);
 472         if (err < 0) {
 473                 mutex_unlock(&dev->device_lock);
 474                 dev_err(dev->dev,
 475                         "Could not disconnect from the ME client");
 476
 477                 return err;
 478         }
 479
 480         /* Flush queues and remove any pending read */
 481         mei_cl_flush_queues(cl);
 482
 483         if (cl->read_cb) {
 484                 struct mei_cl_cb *cb = NULL;
 485
 486                 cb = mei_cl_find_read_cb(cl);
 487                 /* Remove entry from read list */
 488                 if (cb)
 489                         list_del(&cb->list);
 490
 491                 cb = cl->read_cb;
 492                 cl->read_cb = NULL;
 493
 494                 if (cb) {
 495                         mei_io_cb_free(cb);
 496                         cb = NULL;
 497                 }
 498         }
 499
 500         device->event_cb = NULL;
 501
 502         mutex_unlock(&dev->device_lock);
 503
 504         if (!device->ops || !device->ops->disable)
 505                 return 0;
 506
 507         return device->ops->disable(device);
 508 }
 509 EXPORT_SYMBOL_GPL(mei_cl_disable_device);
 510
 511 void mei_cl_bus_rx_event(struct mei_cl *cl)
 512 {
 513         struct mei_cl_device *device = cl->device;
 514
 515         if (!device || !device->event_cb)
 516                 return;
 517
 518         set_bit(MEI_CL_EVENT_RX, &device->events);
 519
 520         schedule_work(&device->event_work);
 521 }
 522
 523 void mei_cl_bus_remove_devices(struct mei_device *dev)
 524 {
 525         struct mei_cl *cl, *next;
 526
 527         mutex_lock(&dev->device_lock);
 528         list_for_each_entry_safe(cl, next, &dev->device_list, device_link) {
 529                 if (cl->device)
 530                         mei_cl_remove_device(cl->device);
 531
 532                 list_del(&cl->device_link);
 533                 mei_cl_unlink(cl);
 534                 kfree(cl);
 535         }
 536         mutex_unlock(&dev->device_lock);
 537 }
 538
 539 int __init mei_cl_bus_init(void)
 540 {
 541         return bus_register(&mei_cl_bus_type);
 542 }
 543
 544 void __exit mei_cl_bus_exit(void)
 545 {
 546         bus_unregister(&mei_cl_bus_type);
 547 }