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