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/signal.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 /**
  34  * __mei_cl_send - internal client send (write)
  35  *
  36  * @cl: host client
  37  * @buf: buffer to send
  38  * @length: buffer length
  39  * @mode: sending mode
  40  *
  41  * Return: written size bytes or < 0 on error
  42  */
  43 ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length,
  44                       unsigned int mode)
  45 {
  46         struct mei_device *bus;
  47         struct mei_cl_cb *cb;
  48         ssize_t rets;
  49
  50         if (WARN_ON(!cl || !cl->dev))
  51                 return -ENODEV;
  52
  53         bus = cl->dev;
  54
  55         mutex_lock(&bus->device_lock);
  56         if (bus->dev_state != MEI_DEV_ENABLED) {
  57                 rets = -ENODEV;
  58                 goto out;
  59         }
  60
  61         if (!mei_cl_is_connected(cl)) {
  62                 rets = -ENODEV;
  63                 goto out;
  64         }
  65
  66         /* Check if we have an ME client device */
  67         if (!mei_me_cl_is_active(cl->me_cl)) {
  68                 rets = -ENOTTY;
  69                 goto out;
  70         }
  71
  72         if (length > mei_cl_mtu(cl)) {
  73                 rets = -EFBIG;
  74                 goto out;
  75         }
  76
  77         while (cl->tx_cb_queued >= bus->tx_queue_limit) {
  78                 mutex_unlock(&bus->device_lock);
  79                 rets = wait_event_interruptible(cl->tx_wait,
  80                                 cl->writing_state == MEI_WRITE_COMPLETE ||
  81                                 (!mei_cl_is_connected(cl)));
  82                 mutex_lock(&bus->device_lock);
  83                 if (rets) {
  84                         if (signal_pending(current))
  85                                 rets = -EINTR;
  86                         goto out;
  87                 }
  88                 if (!mei_cl_is_connected(cl)) {
  89                         rets = -ENODEV;
  90                         goto out;
  91                 }
  92         }
  93
  94         cb = mei_cl_alloc_cb(cl, length, MEI_FOP_WRITE, NULL);
  95         if (!cb) {
  96                 rets = -ENOMEM;
  97                 goto out;
  98         }
  99
 100         cb->internal = !!(mode & MEI_CL_IO_TX_INTERNAL);
 101         cb->blocking = !!(mode & MEI_CL_IO_TX_BLOCKING);
 102         memcpy(cb->buf.data, buf, length);
 103
 104         rets = mei_cl_write(cl, cb);
 105
 106 out:
 107         mutex_unlock(&bus->device_lock);
 108
 109         return rets;
 110 }
 111
 112 /**
 113  * __mei_cl_recv - internal client receive (read)
 114  *
 115  * @cl: host client
 116  * @buf: buffer to receive
 117  * @length: buffer length
 118  * @mode: io mode
 119  *
 120  * Return: read size in bytes of < 0 on error
 121  */
 122 ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length,
 123                       unsigned int mode)
 124 {
 125         struct mei_device *bus;
 126         struct mei_cl_cb *cb;
 127         size_t r_length;
 128         ssize_t rets;
 129         bool nonblock = !!(mode & MEI_CL_IO_RX_NONBLOCK);
 130
 131         if (WARN_ON(!cl || !cl->dev))
 132                 return -ENODEV;
 133
 134         bus = cl->dev;
 135
 136         mutex_lock(&bus->device_lock);
 137         if (bus->dev_state != MEI_DEV_ENABLED) {
 138                 rets = -ENODEV;
 139                 goto out;
 140         }
 141
 142         cb = mei_cl_read_cb(cl, NULL);
 143         if (cb)
 144                 goto copy;
 145
 146         rets = mei_cl_read_start(cl, length, NULL);
 147         if (rets && rets != -EBUSY)
 148                 goto out;
 149
 150         if (nonblock) {
 151                 rets = -EAGAIN;
 152                 goto out;
 153         }
 154
 155         /* wait on event only if there is no other waiter */
 156         /* synchronized under device mutex */
 157         if (!waitqueue_active(&cl->rx_wait)) {
 158
 159                 mutex_unlock(&bus->device_lock);
 160
 161                 if (wait_event_interruptible(cl->rx_wait,
 162                                 (!list_empty(&cl->rd_completed)) ||
 163                                 (!mei_cl_is_connected(cl)))) {
 164
 165                         if (signal_pending(current))
 166                                 return -EINTR;
 167                         return -ERESTARTSYS;
 168                 }
 169
 170                 mutex_lock(&bus->device_lock);
 171
 172                 if (!mei_cl_is_connected(cl)) {
 173                         rets = -ENODEV;
 174                         goto out;
 175                 }
 176         }
 177
 178         cb = mei_cl_read_cb(cl, NULL);
 179         if (!cb) {
 180                 rets = 0;
 181                 goto out;
 182         }
 183
 184 copy:
 185         if (cb->status) {
 186                 rets = cb->status;
 187                 goto free;
 188         }
 189
 190         r_length = min_t(size_t, length, cb->buf_idx);
 191         memcpy(buf, cb->buf.data, r_length);
 192         rets = r_length;
 193
 194 free:
 195         mei_io_cb_free(cb);
 196 out:
 197         mutex_unlock(&bus->device_lock);
 198
 199         return rets;
 200 }
 201
 202 /**
 203  * mei_cldev_send - me device send  (write)
 204  *
 205  * @cldev: me client device
 206  * @buf: buffer to send
 207  * @length: buffer length
 208  *
 209  * Return: written size in bytes or < 0 on error
 210  */
 211 ssize_t mei_cldev_send(struct mei_cl_device *cldev, u8 *buf, size_t length)
 212 {
 213         struct mei_cl *cl = cldev->cl;
 214
 215         return __mei_cl_send(cl, buf, length, MEI_CL_IO_TX_BLOCKING);
 216 }
 217 EXPORT_SYMBOL_GPL(mei_cldev_send);
 218
 219 /**
 220  * mei_cldev_recv_nonblock - non block client receive (read)
 221  *
 222  * @cldev: me client device
 223  * @buf: buffer to receive
 224  * @length: buffer length
 225  *
 226  * Return: read size in bytes of < 0 on error
 227  *         -EAGAIN if function will block.
 228  */
 229 ssize_t mei_cldev_recv_nonblock(struct mei_cl_device *cldev, u8 *buf,
 230                                 size_t length)
 231 {
 232         struct mei_cl *cl = cldev->cl;
 233
 234         return __mei_cl_recv(cl, buf, length, MEI_CL_IO_RX_NONBLOCK);
 235 }
 236 EXPORT_SYMBOL_GPL(mei_cldev_recv_nonblock);
 237
 238 /**
 239  * mei_cldev_recv - client receive (read)
 240  *
 241  * @cldev: me client device
 242  * @buf: buffer to receive
 243  * @length: buffer length
 244  *
 245  * Return: read size in bytes of < 0 on error
 246  */
 247 ssize_t mei_cldev_recv(struct mei_cl_device *cldev, u8 *buf, size_t length)
 248 {
 249         struct mei_cl *cl = cldev->cl;
 250
 251         return __mei_cl_recv(cl, buf, length, 0);
 252 }
 253 EXPORT_SYMBOL_GPL(mei_cldev_recv);
 254
 255 /**
 256  * mei_cl_bus_rx_work - dispatch rx event for a bus device
 257  *
 258  * @work: work
 259  */
 260 static void mei_cl_bus_rx_work(struct work_struct *work)
 261 {
 262         struct mei_cl_device *cldev;
 263         struct mei_device *bus;
 264
 265         cldev = container_of(work, struct mei_cl_device, rx_work);
 266
 267         bus = cldev->bus;
 268
 269         if (cldev->rx_cb)
 270                 cldev->rx_cb(cldev);
 271
 272         mutex_lock(&bus->device_lock);
 273         mei_cl_read_start(cldev->cl, mei_cl_mtu(cldev->cl), NULL);
 274         mutex_unlock(&bus->device_lock);
 275 }
 276
 277 /**
 278  * mei_cl_bus_notif_work - dispatch FW notif event for a bus device
 279  *
 280  * @work: work
 281  */
 282 static void mei_cl_bus_notif_work(struct work_struct *work)
 283 {
 284         struct mei_cl_device *cldev;
 285
 286         cldev = container_of(work, struct mei_cl_device, notif_work);
 287
 288         if (cldev->notif_cb)
 289                 cldev->notif_cb(cldev);
 290 }
 291
 292 /**
 293  * mei_cl_bus_notify_event - schedule notify cb on bus client
 294  *
 295  * @cl: host client
 296  *
 297  * Return: true if event was scheduled
 298  *         false if the client is not waiting for event
 299  */
 300 bool mei_cl_bus_notify_event(struct mei_cl *cl)
 301 {
 302         struct mei_cl_device *cldev = cl->cldev;
 303
 304         if (!cldev || !cldev->notif_cb)
 305                 return false;
 306
 307         if (!cl->notify_ev)
 308                 return false;
 309
 310         schedule_work(&cldev->notif_work);
 311
 312         cl->notify_ev = false;
 313
 314         return true;
 315 }
 316
 317 /**
 318  * mei_cl_bus_rx_event - schedule rx event
 319  *
 320  * @cl: host client
 321  *
 322  * Return: true if event was scheduled
 323  *         false if the client is not waiting for event
 324  */
 325 bool mei_cl_bus_rx_event(struct mei_cl *cl)
 326 {
 327         struct mei_cl_device *cldev = cl->cldev;
 328
 329         if (!cldev || !cldev->rx_cb)
 330                 return false;
 331
 332         schedule_work(&cldev->rx_work);
 333
 334         return true;
 335 }
 336
 337 /**
 338  * mei_cldev_register_rx_cb - register Rx event callback
 339  *
 340  * @cldev: me client devices
 341  * @rx_cb: callback function
 342  *
 343  * Return: 0 on success
 344  *         -EALREADY if an callback is already registered
 345  *         <0 on other errors
 346  */
 347 int mei_cldev_register_rx_cb(struct mei_cl_device *cldev, mei_cldev_cb_t rx_cb)
 348 {
 349         struct mei_device *bus = cldev->bus;
 350         int ret;
 351
 352         if (!rx_cb)
 353                 return -EINVAL;
 354         if (cldev->rx_cb)
 355                 return -EALREADY;
 356
 357         cldev->rx_cb = rx_cb;
 358         INIT_WORK(&cldev->rx_work, mei_cl_bus_rx_work);
 359
 360         mutex_lock(&bus->device_lock);
 361         ret = mei_cl_read_start(cldev->cl, mei_cl_mtu(cldev->cl), NULL);
 362         mutex_unlock(&bus->device_lock);
 363         if (ret && ret != -EBUSY)
 364                 return ret;
 365
 366         return 0;
 367 }
 368 EXPORT_SYMBOL_GPL(mei_cldev_register_rx_cb);
 369
 370 /**
 371  * mei_cldev_register_notif_cb - register FW notification event callback
 372  *
 373  * @cldev: me client devices
 374  * @notif_cb: callback function
 375  *
 376  * Return: 0 on success
 377  *         -EALREADY if an callback is already registered
 378  *         <0 on other errors
 379  */
 380 int mei_cldev_register_notif_cb(struct mei_cl_device *cldev,
 381                                 mei_cldev_cb_t notif_cb)
 382 {
 383         struct mei_device *bus = cldev->bus;
 384         int ret;
 385
 386         if (!notif_cb)
 387                 return -EINVAL;
 388
 389         if (cldev->notif_cb)
 390                 return -EALREADY;
 391
 392         cldev->notif_cb = notif_cb;
 393         INIT_WORK(&cldev->notif_work, mei_cl_bus_notif_work);
 394
 395         mutex_lock(&bus->device_lock);
 396         ret = mei_cl_notify_request(cldev->cl, NULL, 1);
 397         mutex_unlock(&bus->device_lock);
 398         if (ret)
 399                 return ret;
 400
 401         return 0;
 402 }
 403 EXPORT_SYMBOL_GPL(mei_cldev_register_notif_cb);
 404
 405 /**
 406  * mei_cldev_get_drvdata - driver data getter
 407  *
 408  * @cldev: mei client device
 409  *
 410  * Return: driver private data
 411  */
 412 void *mei_cldev_get_drvdata(const struct mei_cl_device *cldev)
 413 {
 414         return dev_get_drvdata(&cldev->dev);
 415 }
 416 EXPORT_SYMBOL_GPL(mei_cldev_get_drvdata);
 417
 418 /**
 419  * mei_cldev_set_drvdata - driver data setter
 420  *
 421  * @cldev: mei client device
 422  * @data: data to store
 423  */
 424 void mei_cldev_set_drvdata(struct mei_cl_device *cldev, void *data)
 425 {
 426         dev_set_drvdata(&cldev->dev, data);
 427 }
 428 EXPORT_SYMBOL_GPL(mei_cldev_set_drvdata);
 429
 430 /**
 431  * mei_cldev_uuid - return uuid of the underlying me client
 432  *
 433  * @cldev: mei client device
 434  *
 435  * Return: me client uuid
 436  */
 437 const uuid_le *mei_cldev_uuid(const struct mei_cl_device *cldev)
 438 {
 439         return mei_me_cl_uuid(cldev->me_cl);
 440 }
 441 EXPORT_SYMBOL_GPL(mei_cldev_uuid);
 442
 443 /**
 444  * mei_cldev_ver - return protocol version of the underlying me client
 445  *
 446  * @cldev: mei client device
 447  *
 448  * Return: me client protocol version
 449  */
 450 u8 mei_cldev_ver(const struct mei_cl_device *cldev)
 451 {
 452         return mei_me_cl_ver(cldev->me_cl);
 453 }
 454 EXPORT_SYMBOL_GPL(mei_cldev_ver);
 455
 456 /**
 457  * mei_cldev_enabled - check whether the device is enabled
 458  *
 459  * @cldev: mei client device
 460  *
 461  * Return: true if me client is initialized and connected
 462  */
 463 bool mei_cldev_enabled(struct mei_cl_device *cldev)
 464 {
 465         return mei_cl_is_connected(cldev->cl);
 466 }
 467 EXPORT_SYMBOL_GPL(mei_cldev_enabled);
 468
 469 /**
 470  * mei_cl_bus_module_get - acquire module of the underlying
 471  *    hw driver.
 472  *
 473  * @cldev: mei client device
 474  *
 475  * Return: true on success; false if the module was removed.
 476  */
 477 static bool mei_cl_bus_module_get(struct mei_cl_device *cldev)
 478 {
 479         return try_module_get(cldev->bus->dev->driver->owner);
 480 }
 481
 482 /**
 483  * mei_cl_bus_module_put -  release the underlying hw module.
 484  *
 485  * @cldev: mei client device
 486  */
 487 static void mei_cl_bus_module_put(struct mei_cl_device *cldev)
 488 {
 489         module_put(cldev->bus->dev->driver->owner);
 490 }
 491
 492 /**
 493  * mei_cldev_enable - enable me client device
 494  *     create connection with me client
 495  *
 496  * @cldev: me client device
 497  *
 498  * Return: 0 on success and < 0 on error
 499  */
 500 int mei_cldev_enable(struct mei_cl_device *cldev)
 501 {
 502         struct mei_device *bus = cldev->bus;
 503         struct mei_cl *cl;
 504         int ret;
 505
 506         cl = cldev->cl;
 507
 508         mutex_lock(&bus->device_lock);
 509         if (cl->state == MEI_FILE_UNINITIALIZED) {
 510                 ret = mei_cl_link(cl);
 511                 if (ret)
 512                         goto out;
 513                 /* update pointers */
 514                 cl->cldev = cldev;
 515         }
 516
 517         if (mei_cl_is_connected(cl)) {
 518                 ret = 0;
 519                 goto out;
 520         }
 521
 522         if (!mei_me_cl_is_active(cldev->me_cl)) {
 523                 dev_err(&cldev->dev, "me client is not active\n");
 524                 ret = -ENOTTY;
 525                 goto out;
 526         }
 527
 528         if (!mei_cl_bus_module_get(cldev)) {
 529                 dev_err(&cldev->dev, "get hw module failed");
 530                 ret = -ENODEV;
 531                 goto out;
 532         }
 533
 534         ret = mei_cl_connect(cl, cldev->me_cl, NULL);
 535         if (ret < 0) {
 536                 dev_err(&cldev->dev, "cannot connect\n");
 537                 mei_cl_bus_module_put(cldev);
 538         }
 539
 540 out:
 541         mutex_unlock(&bus->device_lock);
 542
 543         return ret;
 544 }
 545 EXPORT_SYMBOL_GPL(mei_cldev_enable);
 546
 547 /**
 548  * mei_cldev_unregister_callbacks - internal wrapper for unregistering
 549  *  callbacks.
 550  *
 551  * @cldev: client device
 552  */
 553 static void mei_cldev_unregister_callbacks(struct mei_cl_device *cldev)
 554 {
 555         if (cldev->rx_cb) {
 556                 cancel_work_sync(&cldev->rx_work);
 557                 cldev->rx_cb = NULL;
 558         }
 559
 560         if (cldev->notif_cb) {
 561                 cancel_work_sync(&cldev->notif_work);
 562                 cldev->notif_cb = NULL;
 563         }
 564 }
 565
 566 /**
 567  * mei_cldev_disable - disable me client device
 568  *     disconnect form the me client
 569  *
 570  * @cldev: me client device
 571  *
 572  * Return: 0 on success and < 0 on error
 573  */
 574 int mei_cldev_disable(struct mei_cl_device *cldev)
 575 {
 576         struct mei_device *bus;
 577         struct mei_cl *cl;
 578         int err;
 579
 580         if (!cldev)
 581                 return -ENODEV;
 582
 583         cl = cldev->cl;
 584
 585         bus = cldev->bus;
 586
 587         mei_cldev_unregister_callbacks(cldev);
 588
 589         mutex_lock(&bus->device_lock);
 590
 591         if (!mei_cl_is_connected(cl)) {
 592                 dev_dbg(bus->dev, "Already disconnected\n");
 593                 err = 0;
 594                 goto out;
 595         }
 596
 597         err = mei_cl_disconnect(cl);
 598         if (err < 0)
 599                 dev_err(bus->dev, "Could not disconnect from the ME client\n");
 600
 601         mei_cl_bus_module_put(cldev);
 602 out:
 603         /* Flush queues and remove any pending read */
 604         mei_cl_flush_queues(cl, NULL);
 605         mei_cl_unlink(cl);
 606
 607         mutex_unlock(&bus->device_lock);
 608         return err;
 609 }
 610 EXPORT_SYMBOL_GPL(mei_cldev_disable);
 611
 612 /**
 613  * mei_cl_device_find - find matching entry in the driver id table
 614  *
 615  * @cldev: me client device
 616  * @cldrv: me client driver
 617  *
 618  * Return: id on success; NULL if no id is matching
 619  */
 620 static const
 621 struct mei_cl_device_id *mei_cl_device_find(struct mei_cl_device *cldev,
 622                                             struct mei_cl_driver *cldrv)
 623 {
 624         const struct mei_cl_device_id *id;
 625         const uuid_le *uuid;
 626         u8 version;
 627         bool match;
 628
 629         uuid = mei_me_cl_uuid(cldev->me_cl);
 630         version = mei_me_cl_ver(cldev->me_cl);
 631
 632         id = cldrv->id_table;
 633         while (uuid_le_cmp(NULL_UUID_LE, id->uuid)) {
 634                 if (!uuid_le_cmp(*uuid, id->uuid)) {
 635                         match = true;
 636
 637                         if (cldev->name[0])
 638                                 if (strncmp(cldev->name, id->name,
 639                                             sizeof(id->name)))
 640                                         match = false;
 641
 642                         if (id->version != MEI_CL_VERSION_ANY)
 643                                 if (id->version != version)
 644                                         match = false;
 645                         if (match)
 646                                 return id;
 647                 }
 648
 649                 id++;
 650         }
 651
 652         return NULL;
 653 }
 654
 655 /**
 656  * mei_cl_device_match  - device match function
 657  *
 658  * @dev: device
 659  * @drv: driver
 660  *
 661  * Return:  1 if matching device was found 0 otherwise
 662  */
 663 static int mei_cl_device_match(struct device *dev, struct device_driver *drv)
 664 {
 665         struct mei_cl_device *cldev = to_mei_cl_device(dev);
 666         struct mei_cl_driver *cldrv = to_mei_cl_driver(drv);
 667         const struct mei_cl_device_id *found_id;
 668
 669         if (!cldev)
 670                 return 0;
 671
 672         if (!cldev->do_match)
 673                 return 0;
 674
 675         if (!cldrv || !cldrv->id_table)
 676                 return 0;
 677
 678         found_id = mei_cl_device_find(cldev, cldrv);
 679         if (found_id)
 680                 return 1;
 681
 682         return 0;
 683 }
 684
 685 /**
 686  * mei_cl_device_probe - bus probe function
 687  *
 688  * @dev: device
 689  *
 690  * Return:  0 on success; < 0 otherwise
 691  */
 692 static int mei_cl_device_probe(struct device *dev)
 693 {
 694         struct mei_cl_device *cldev;
 695         struct mei_cl_driver *cldrv;
 696         const struct mei_cl_device_id *id;
 697         int ret;
 698
 699         cldev = to_mei_cl_device(dev);
 700         cldrv = to_mei_cl_driver(dev->driver);
 701
 702         if (!cldev)
 703                 return 0;
 704
 705         if (!cldrv || !cldrv->probe)
 706                 return -ENODEV;
 707
 708         id = mei_cl_device_find(cldev, cldrv);
 709         if (!id)
 710                 return -ENODEV;
 711
 712         ret = cldrv->probe(cldev, id);
 713         if (ret)
 714                 return ret;
 715
 716         __module_get(THIS_MODULE);
 717         return 0;
 718 }
 719
 720 /**
 721  * mei_cl_device_remove - remove device from the bus
 722  *
 723  * @dev: device
 724  *
 725  * Return:  0 on success; < 0 otherwise
 726  */
 727 static int mei_cl_device_remove(struct device *dev)
 728 {
 729         struct mei_cl_device *cldev = to_mei_cl_device(dev);
 730         struct mei_cl_driver *cldrv;
 731         int ret = 0;
 732
 733         if (!cldev || !dev->driver)
 734                 return 0;
 735
 736         cldrv = to_mei_cl_driver(dev->driver);
 737         if (cldrv->remove)
 738                 ret = cldrv->remove(cldev);
 739
 740         mei_cldev_unregister_callbacks(cldev);
 741
 742         module_put(THIS_MODULE);
 743         dev->driver = NULL;
 744         return ret;
 745
 746 }
 747
 748 static ssize_t name_show(struct device *dev, struct device_attribute *a,
 749                              char *buf)
 750 {
 751         struct mei_cl_device *cldev = to_mei_cl_device(dev);
 752
 753         return scnprintf(buf, PAGE_SIZE, "%s", cldev->name);
 754 }
 755 static DEVICE_ATTR_RO(name);
 756
 757 static ssize_t uuid_show(struct device *dev, struct device_attribute *a,
 758                              char *buf)
 759 {
 760         struct mei_cl_device *cldev = to_mei_cl_device(dev);
 761         const uuid_le *uuid = mei_me_cl_uuid(cldev->me_cl);
 762
 763         return scnprintf(buf, PAGE_SIZE, "%pUl", uuid);
 764 }
 765 static DEVICE_ATTR_RO(uuid);
 766
 767 static ssize_t version_show(struct device *dev, struct device_attribute *a,
 768                              char *buf)
 769 {
 770         struct mei_cl_device *cldev = to_mei_cl_device(dev);
 771         u8 version = mei_me_cl_ver(cldev->me_cl);
 772
 773         return scnprintf(buf, PAGE_SIZE, "%02X", version);
 774 }
 775 static DEVICE_ATTR_RO(version);
 776
 777 static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
 778                              char *buf)
 779 {
 780         struct mei_cl_device *cldev = to_mei_cl_device(dev);
 781         const uuid_le *uuid = mei_me_cl_uuid(cldev->me_cl);
 782         u8 version = mei_me_cl_ver(cldev->me_cl);
 783
 784         return scnprintf(buf, PAGE_SIZE, "mei:%s:%pUl:%02X:",
 785                          cldev->name, uuid, version);
 786 }
 787 static DEVICE_ATTR_RO(modalias);
 788
 789 static struct attribute *mei_cldev_attrs[] = {
 790         &dev_attr_name.attr,
 791         &dev_attr_uuid.attr,
 792         &dev_attr_version.attr,
 793         &dev_attr_modalias.attr,
 794         NULL,
 795 };
 796 ATTRIBUTE_GROUPS(mei_cldev);
 797
 798 /**
 799  * mei_cl_device_uevent - me client bus uevent handler
 800  *
 801  * @dev: device
 802  * @env: uevent kobject
 803  *
 804  * Return: 0 on success -ENOMEM on when add_uevent_var fails
 805  */
 806 static int mei_cl_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 807 {
 808         struct mei_cl_device *cldev = to_mei_cl_device(dev);
 809         const uuid_le *uuid = mei_me_cl_uuid(cldev->me_cl);
 810         u8 version = mei_me_cl_ver(cldev->me_cl);
 811
 812         if (add_uevent_var(env, "MEI_CL_VERSION=%d", version))
 813                 return -ENOMEM;
 814
 815         if (add_uevent_var(env, "MEI_CL_UUID=%pUl", uuid))
 816                 return -ENOMEM;
 817
 818         if (add_uevent_var(env, "MEI_CL_NAME=%s", cldev->name))
 819                 return -ENOMEM;
 820
 821         if (add_uevent_var(env, "MODALIAS=mei:%s:%pUl:%02X:",
 822                            cldev->name, uuid, version))
 823                 return -ENOMEM;
 824
 825         return 0;
 826 }
 827
 828 static struct bus_type mei_cl_bus_type = {
 829         .name           = "mei",
 830         .dev_groups     = mei_cldev_groups,
 831         .match          = mei_cl_device_match,
 832         .probe          = mei_cl_device_probe,
 833         .remove         = mei_cl_device_remove,
 834         .uevent         = mei_cl_device_uevent,
 835 };
 836
 837 static struct mei_device *mei_dev_bus_get(struct mei_device *bus)
 838 {
 839         if (bus)
 840                 get_device(bus->dev);
 841
 842         return bus;
 843 }
 844
 845 static void mei_dev_bus_put(struct mei_device *bus)
 846 {
 847         if (bus)
 848                 put_device(bus->dev);
 849 }
 850
 851 static void mei_cl_bus_dev_release(struct device *dev)
 852 {
 853         struct mei_cl_device *cldev = to_mei_cl_device(dev);
 854
 855         if (!cldev)
 856                 return;
 857
 858         mei_me_cl_put(cldev->me_cl);
 859         mei_dev_bus_put(cldev->bus);
 860         mei_cl_unlink(cldev->cl);
 861         kfree(cldev->cl);
 862         kfree(cldev);
 863 }
 864
 865 static const struct device_type mei_cl_device_type = {
 866         .release = mei_cl_bus_dev_release,
 867 };
 868
 869 /**
 870  * mei_cl_bus_set_name - set device name for me client device
 871  *
 872  * @cldev: me client device
 873  */
 874 static inline void mei_cl_bus_set_name(struct mei_cl_device *cldev)
 875 {
 876         dev_set_name(&cldev->dev, "mei:%s:%pUl:%02X",
 877                      cldev->name,
 878                      mei_me_cl_uuid(cldev->me_cl),
 879                      mei_me_cl_ver(cldev->me_cl));
 880 }
 881
 882 /**
 883  * mei_cl_bus_dev_alloc - initialize and allocate mei client device
 884  *
 885  * @bus: mei device
 886  * @me_cl: me client
 887  *
 888  * Return: allocated device structur or NULL on allocation failure
 889  */
 890 static struct mei_cl_device *mei_cl_bus_dev_alloc(struct mei_device *bus,
 891                                                   struct mei_me_client *me_cl)
 892 {
 893         struct mei_cl_device *cldev;
 894         struct mei_cl *cl;
 895
 896         cldev = kzalloc(sizeof(struct mei_cl_device), GFP_KERNEL);
 897         if (!cldev)
 898                 return NULL;
 899
 900         cl = mei_cl_allocate(bus);
 901         if (!cl) {
 902                 kfree(cldev);
 903                 return NULL;
 904         }
 905
 906         device_initialize(&cldev->dev);
 907         cldev->dev.parent = bus->dev;
 908         cldev->dev.bus    = &mei_cl_bus_type;
 909         cldev->dev.type   = &mei_cl_device_type;
 910         cldev->bus        = mei_dev_bus_get(bus);
 911         cldev->me_cl      = mei_me_cl_get(me_cl);
 912         cldev->cl         = cl;
 913         mei_cl_bus_set_name(cldev);
 914         cldev->is_added   = 0;
 915         INIT_LIST_HEAD(&cldev->bus_list);
 916
 917         return cldev;
 918 }
 919
 920 /**
 921  * mei_cl_dev_setup - setup me client device
 922  *    run fix up routines and set the device name
 923  *
 924  * @bus: mei device
 925  * @cldev: me client device
 926  *
 927  * Return: true if the device is eligible for enumeration
 928  */
 929 static bool mei_cl_bus_dev_setup(struct mei_device *bus,
 930                                  struct mei_cl_device *cldev)
 931 {
 932         cldev->do_match = 1;
 933         mei_cl_bus_dev_fixup(cldev);
 934
 935         /* the device name can change during fix up */
 936         if (cldev->do_match)
 937                 mei_cl_bus_set_name(cldev);
 938
 939         return cldev->do_match == 1;
 940 }
 941
 942 /**
 943  * mei_cl_bus_dev_add - add me client devices
 944  *
 945  * @cldev: me client device
 946  *
 947  * Return: 0 on success; < 0 on failre
 948  */
 949 static int mei_cl_bus_dev_add(struct mei_cl_device *cldev)
 950 {
 951         int ret;
 952
 953         dev_dbg(cldev->bus->dev, "adding %pUL:%02X\n",
 954                 mei_me_cl_uuid(cldev->me_cl),
 955                 mei_me_cl_ver(cldev->me_cl));
 956         ret = device_add(&cldev->dev);
 957         if (!ret)
 958                 cldev->is_added = 1;
 959
 960         return ret;
 961 }
 962
 963 /**
 964  * mei_cl_bus_dev_stop - stop the driver
 965  *
 966  * @cldev: me client device
 967  */
 968 static void mei_cl_bus_dev_stop(struct mei_cl_device *cldev)
 969 {
 970         if (cldev->is_added)
 971                 device_release_driver(&cldev->dev);
 972 }
 973
 974 /**
 975  * mei_cl_bus_dev_destroy - destroy me client devices object
 976  *
 977  * @cldev: me client device
 978  *
 979  * Locking: called under "dev->cl_bus_lock" lock
 980  */
 981 static void mei_cl_bus_dev_destroy(struct mei_cl_device *cldev)
 982 {
 983
 984         WARN_ON(!mutex_is_locked(&cldev->bus->cl_bus_lock));
 985
 986         if (!cldev->is_added)
 987                 return;
 988
 989         device_del(&cldev->dev);
 990
 991         list_del_init(&cldev->bus_list);
 992
 993         cldev->is_added = 0;
 994         put_device(&cldev->dev);
 995 }
 996
 997 /**
 998  * mei_cl_bus_remove_device - remove a devices form the bus
 999  *
1000  * @cldev: me client device
1001  */
1002 static void mei_cl_bus_remove_device(struct mei_cl_device *cldev)
1003 {
1004         mei_cl_bus_dev_stop(cldev);
1005         mei_cl_bus_dev_destroy(cldev);
1006 }
1007
1008 /**
1009  * mei_cl_bus_remove_devices - remove all devices form the bus
1010  *
1011  * @bus: mei device
1012  */
1013 void mei_cl_bus_remove_devices(struct mei_device *bus)
1014 {
1015         struct mei_cl_device *cldev, *next;
1016
1017         mutex_lock(&bus->cl_bus_lock);
1018         list_for_each_entry_safe(cldev, next, &bus->device_list, bus_list)
1019                 mei_cl_bus_remove_device(cldev);
1020         mutex_unlock(&bus->cl_bus_lock);
1021 }
1022
1023
1024 /**
1025  * mei_cl_bus_dev_init - allocate and initializes an mei client devices
1026  *     based on me client
1027  *
1028  * @bus: mei device
1029  * @me_cl: me client
1030  *
1031  * Locking: called under "dev->cl_bus_lock" lock
1032  */
1033 static void mei_cl_bus_dev_init(struct mei_device *bus,
1034                                 struct mei_me_client *me_cl)
1035 {
1036         struct mei_cl_device *cldev;
1037
1038         WARN_ON(!mutex_is_locked(&bus->cl_bus_lock));
1039
1040         dev_dbg(bus->dev, "initializing %pUl", mei_me_cl_uuid(me_cl));
1041
1042         if (me_cl->bus_added)
1043                 return;
1044
1045         cldev = mei_cl_bus_dev_alloc(bus, me_cl);
1046         if (!cldev)
1047                 return;
1048
1049         me_cl->bus_added = true;
1050         list_add_tail(&cldev->bus_list, &bus->device_list);
1051
1052 }
1053
1054 /**
1055  * mei_cl_bus_rescan - scan me clients list and add create
1056  *    devices for eligible clients
1057  *
1058  * @bus: mei device
1059  */
1060 static void mei_cl_bus_rescan(struct mei_device *bus)
1061 {
1062         struct mei_cl_device *cldev, *n;
1063         struct mei_me_client *me_cl;
1064
1065         mutex_lock(&bus->cl_bus_lock);
1066
1067         down_read(&bus->me_clients_rwsem);
1068         list_for_each_entry(me_cl, &bus->me_clients, list)
1069                 mei_cl_bus_dev_init(bus, me_cl);
1070         up_read(&bus->me_clients_rwsem);
1071
1072         list_for_each_entry_safe(cldev, n, &bus->device_list, bus_list) {
1073
1074                 if (!mei_me_cl_is_active(cldev->me_cl)) {
1075                         mei_cl_bus_remove_device(cldev);
1076                         continue;
1077                 }
1078
1079                 if (cldev->is_added)
1080                         continue;
1081
1082                 if (mei_cl_bus_dev_setup(bus, cldev))
1083                         mei_cl_bus_dev_add(cldev);
1084                 else {
1085                         list_del_init(&cldev->bus_list);
1086                         put_device(&cldev->dev);
1087                 }
1088         }
1089         mutex_unlock(&bus->cl_bus_lock);
1090
1091         dev_dbg(bus->dev, "rescan end");
1092 }
1093
1094 void mei_cl_bus_rescan_work(struct work_struct *work)
1095 {
1096         struct mei_device *bus =
1097                 container_of(work, struct mei_device, bus_rescan_work);
1098
1099         mei_cl_bus_rescan(bus);
1100 }
1101
1102 int __mei_cldev_driver_register(struct mei_cl_driver *cldrv,
1103                                 struct module *owner)
1104 {
1105         int err;
1106
1107         cldrv->driver.name = cldrv->name;
1108         cldrv->driver.owner = owner;
1109         cldrv->driver.bus = &mei_cl_bus_type;
1110
1111         err = driver_register(&cldrv->driver);
1112         if (err)
1113                 return err;
1114
1115         pr_debug("mei: driver [%s] registered\n", cldrv->driver.name);
1116
1117         return 0;
1118 }
1119 EXPORT_SYMBOL_GPL(__mei_cldev_driver_register);
1120
1121 void mei_cldev_driver_unregister(struct mei_cl_driver *cldrv)
1122 {
1123         driver_unregister(&cldrv->driver);
1124
1125         pr_debug("mei: driver [%s] unregistered\n", cldrv->driver.name);
1126 }
1127 EXPORT_SYMBOL_GPL(mei_cldev_driver_unregister);
1128
1129
1130 int __init mei_cl_bus_init(void)
1131 {
1132         return bus_register(&mei_cl_bus_type);
1133 }
1134
1135 void __exit mei_cl_bus_exit(void)
1136 {
1137         bus_unregister(&mei_cl_bus_type);
1138 }