drivers/gpu/host1x/bus.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012 Avionic Design GmbH
   4  * Copyright (C) 2012-2013, NVIDIA Corporation
   5  */
   6
   7 #include <linux/debugfs.h>
   8 #include <linux/host1x.h>
   9 #include <linux/of.h>
  10 #include <linux/seq_file.h>
  11 #include <linux/slab.h>
  12 #include <linux/of_device.h>
  13
  14 #include "bus.h"
  15 #include "dev.h"
  16
  17 static DEFINE_MUTEX(clients_lock);
  18 static LIST_HEAD(clients);
  19
  20 static DEFINE_MUTEX(drivers_lock);
  21 static LIST_HEAD(drivers);
  22
  23 static DEFINE_MUTEX(devices_lock);
  24 static LIST_HEAD(devices);
  25
  26 struct host1x_subdev {
  27         struct host1x_client *client;
  28         struct device_node *np;
  29         struct list_head list;
  30 };
  31
  32 /**
  33  * host1x_subdev_add() - add a new subdevice with an associated device node
  34  * @device: host1x device to add the subdevice to
  35  * @driver: host1x driver containing the subdevices
  36  * @np: device node
  37  */
  38 static int host1x_subdev_add(struct host1x_device *device,
  39                              struct host1x_driver *driver,
  40                              struct device_node *np)
  41 {
  42         struct host1x_subdev *subdev;
  43         struct device_node *child;
  44         int err;
  45
  46         subdev = kzalloc(sizeof(*subdev), GFP_KERNEL);
  47         if (!subdev)
  48                 return -ENOMEM;
  49
  50         INIT_LIST_HEAD(&subdev->list);
  51         subdev->np = of_node_get(np);
  52
  53         mutex_lock(&device->subdevs_lock);
  54         list_add_tail(&subdev->list, &device->subdevs);
  55         mutex_unlock(&device->subdevs_lock);
  56
  57         /* recursively add children */
  58         for_each_child_of_node(np, child) {
  59                 if (of_match_node(driver->subdevs, child) &&
  60                     of_device_is_available(child)) {
  61                         err = host1x_subdev_add(device, driver, child);
  62                         if (err < 0) {
  63                                 /* XXX cleanup? */
  64                                 of_node_put(child);
  65                                 return err;
  66                         }
  67                 }
  68         }
  69
  70         return 0;
  71 }
  72
  73 /**
  74  * host1x_subdev_del() - remove subdevice
  75  * @subdev: subdevice to remove
  76  */
  77 static void host1x_subdev_del(struct host1x_subdev *subdev)
  78 {
  79         list_del(&subdev->list);
  80         of_node_put(subdev->np);
  81         kfree(subdev);
  82 }
  83
  84 /**
  85  * host1x_device_parse_dt() - scan device tree and add matching subdevices
  86  * @device: host1x logical device
  87  * @driver: host1x driver
  88  */
  89 static int host1x_device_parse_dt(struct host1x_device *device,
  90                                   struct host1x_driver *driver)
  91 {
  92         struct device_node *np;
  93         int err;
  94
  95         for_each_child_of_node(device->dev.parent->of_node, np) {
  96                 if (of_match_node(driver->subdevs, np) &&
  97                     of_device_is_available(np)) {
  98                         err = host1x_subdev_add(device, driver, np);
  99                         if (err < 0) {
 100                                 of_node_put(np);
 101                                 return err;
 102                         }
 103                 }
 104         }
 105
 106         return 0;
 107 }
 108
 109 static void host1x_subdev_register(struct host1x_device *device,
 110                                    struct host1x_subdev *subdev,
 111                                    struct host1x_client *client)
 112 {
 113         int err;
 114
 115         /*
 116          * Move the subdevice to the list of active (registered) subdevices
 117          * and associate it with a client. At the same time, associate the
 118          * client with its parent device.
 119          */
 120         mutex_lock(&device->subdevs_lock);
 121         mutex_lock(&device->clients_lock);
 122         list_move_tail(&client->list, &device->clients);
 123         list_move_tail(&subdev->list, &device->active);
 124         client->host = &device->dev;
 125         subdev->client = client;
 126         mutex_unlock(&device->clients_lock);
 127         mutex_unlock(&device->subdevs_lock);
 128
 129         if (list_empty(&device->subdevs)) {
 130                 err = device_add(&device->dev);
 131                 if (err < 0)
 132                         dev_err(&device->dev, "failed to add: %d\n", err);
 133                 else
 134                         device->registered = true;
 135         }
 136 }
 137
 138 static void __host1x_subdev_unregister(struct host1x_device *device,
 139                                        struct host1x_subdev *subdev)
 140 {
 141         struct host1x_client *client = subdev->client;
 142
 143         /*
 144          * If all subdevices have been activated, we're about to remove the
 145          * first active subdevice, so unload the driver first.
 146          */
 147         if (list_empty(&device->subdevs)) {
 148                 if (device->registered) {
 149                         device->registered = false;
 150                         device_del(&device->dev);
 151                 }
 152         }
 153
 154         /*
 155          * Move the subdevice back to the list of idle subdevices and remove
 156          * it from list of clients.
 157          */
 158         mutex_lock(&device->clients_lock);
 159         subdev->client = NULL;
 160         client->host = NULL;
 161         list_move_tail(&subdev->list, &device->subdevs);
 162         /*
 163          * XXX: Perhaps don't do this here, but rather explicitly remove it
 164          * when the device is about to be deleted.
 165          *
 166          * This is somewhat complicated by the fact that this function is
 167          * used to remove the subdevice when a client is unregistered but
 168          * also when the composite device is about to be removed.
 169          */
 170         list_del_init(&client->list);
 171         mutex_unlock(&device->clients_lock);
 172 }
 173
 174 static void host1x_subdev_unregister(struct host1x_device *device,
 175                                      struct host1x_subdev *subdev)
 176 {
 177         mutex_lock(&device->subdevs_lock);
 178         __host1x_subdev_unregister(device, subdev);
 179         mutex_unlock(&device->subdevs_lock);
 180 }
 181
 182 /**
 183  * host1x_device_init() - initialize a host1x logical device
 184  * @device: host1x logical device
 185  *
 186  * The driver for the host1x logical device can call this during execution of
 187  * its &host1x_driver.probe implementation to initialize each of its clients.
 188  * The client drivers access the subsystem specific driver data using the
 189  * &host1x_client.parent field and driver data associated with it (usually by
 190  * calling dev_get_drvdata()).
 191  */
 192 int host1x_device_init(struct host1x_device *device)
 193 {
 194         struct host1x_client *client;
 195         int err;
 196
 197         mutex_lock(&device->clients_lock);
 198
 199         list_for_each_entry(client, &device->clients, list) {
 200                 if (client->ops && client->ops->init) {
 201                         err = client->ops->init(client);
 202                         if (err < 0) {
 203                                 dev_err(&device->dev,
 204                                         "failed to initialize %s: %d\n",
 205                                         dev_name(client->dev), err);
 206                                 goto teardown;
 207                         }
 208                 }
 209         }
 210
 211         mutex_unlock(&device->clients_lock);
 212
 213         return 0;
 214
 215 teardown:
 216         list_for_each_entry_continue_reverse(client, &device->clients, list)
 217                 if (client->ops->exit)
 218                         client->ops->exit(client);
 219
 220         mutex_unlock(&device->clients_lock);
 221         return err;
 222 }
 223 EXPORT_SYMBOL(host1x_device_init);
 224
 225 /**
 226  * host1x_device_exit() - uninitialize host1x logical device
 227  * @device: host1x logical device
 228  *
 229  * When the driver for a host1x logical device is unloaded, it can call this
 230  * function to tear down each of its clients. Typically this is done after a
 231  * subsystem-specific data structure is removed and the functionality can no
 232  * longer be used.
 233  */
 234 int host1x_device_exit(struct host1x_device *device)
 235 {
 236         struct host1x_client *client;
 237         int err;
 238
 239         mutex_lock(&device->clients_lock);
 240
 241         list_for_each_entry_reverse(client, &device->clients, list) {
 242                 if (client->ops && client->ops->exit) {
 243                         err = client->ops->exit(client);
 244                         if (err < 0) {
 245                                 dev_err(&device->dev,
 246                                         "failed to cleanup %s: %d\n",
 247                                         dev_name(client->dev), err);
 248                                 mutex_unlock(&device->clients_lock);
 249                                 return err;
 250                         }
 251                 }
 252         }
 253
 254         mutex_unlock(&device->clients_lock);
 255
 256         return 0;
 257 }
 258 EXPORT_SYMBOL(host1x_device_exit);
 259
 260 static int host1x_add_client(struct host1x *host1x,
 261                              struct host1x_client *client)
 262 {
 263         struct host1x_device *device;
 264         struct host1x_subdev *subdev;
 265
 266         mutex_lock(&host1x->devices_lock);
 267
 268         list_for_each_entry(device, &host1x->devices, list) {
 269                 list_for_each_entry(subdev, &device->subdevs, list) {
 270                         if (subdev->np == client->dev->of_node) {
 271                                 host1x_subdev_register(device, subdev, client);
 272                                 mutex_unlock(&host1x->devices_lock);
 273                                 return 0;
 274                         }
 275                 }
 276         }
 277
 278         mutex_unlock(&host1x->devices_lock);
 279         return -ENODEV;
 280 }
 281
 282 static int host1x_del_client(struct host1x *host1x,
 283                              struct host1x_client *client)
 284 {
 285         struct host1x_device *device, *dt;
 286         struct host1x_subdev *subdev;
 287
 288         mutex_lock(&host1x->devices_lock);
 289
 290         list_for_each_entry_safe(device, dt, &host1x->devices, list) {
 291                 list_for_each_entry(subdev, &device->active, list) {
 292                         if (subdev->client == client) {
 293                                 host1x_subdev_unregister(device, subdev);
 294                                 mutex_unlock(&host1x->devices_lock);
 295                                 return 0;
 296                         }
 297                 }
 298         }
 299
 300         mutex_unlock(&host1x->devices_lock);
 301         return -ENODEV;
 302 }
 303
 304 static int host1x_device_match(struct device *dev, struct device_driver *drv)
 305 {
 306         return strcmp(dev_name(dev), drv->name) == 0;
 307 }
 308
 309 static int host1x_device_uevent(struct device *dev,
 310                                 struct kobj_uevent_env *env)
 311 {
 312         struct device_node *np = dev->parent->of_node;
 313         unsigned int count = 0;
 314         struct property *p;
 315         const char *compat;
 316
 317         /*
 318          * This duplicates most of of_device_uevent(), but the latter cannot
 319          * be called from modules and operates on dev->of_node, which is not
 320          * available in this case.
 321          *
 322          * Note that this is really only needed for backwards compatibility
 323          * with libdrm, which parses this information from sysfs and will
 324          * fail if it can't find the OF_FULLNAME, specifically.
 325          */
 326         add_uevent_var(env, "OF_NAME=%pOFn", np);
 327         add_uevent_var(env, "OF_FULLNAME=%pOF", np);
 328
 329         of_property_for_each_string(np, "compatible", p, compat) {
 330                 add_uevent_var(env, "OF_COMPATIBLE_%u=%s", count, compat);
 331                 count++;
 332         }
 333
 334         add_uevent_var(env, "OF_COMPATIBLE_N=%u", count);
 335
 336         return 0;
 337 }
 338
 339 static int host1x_dma_configure(struct device *dev)
 340 {
 341         return of_dma_configure(dev, dev->of_node, true);
 342 }
 343
 344 static const struct dev_pm_ops host1x_device_pm_ops = {
 345         .suspend = pm_generic_suspend,
 346         .resume = pm_generic_resume,
 347         .freeze = pm_generic_freeze,
 348         .thaw = pm_generic_thaw,
 349         .poweroff = pm_generic_poweroff,
 350         .restore = pm_generic_restore,
 351 };
 352
 353 struct bus_type host1x_bus_type = {
 354         .name = "host1x",
 355         .match = host1x_device_match,
 356         .uevent = host1x_device_uevent,
 357         .dma_configure = host1x_dma_configure,
 358         .pm = &host1x_device_pm_ops,
 359 };
 360
 361 static void __host1x_device_del(struct host1x_device *device)
 362 {
 363         struct host1x_subdev *subdev, *sd;
 364         struct host1x_client *client, *cl;
 365
 366         mutex_lock(&device->subdevs_lock);
 367
 368         /* unregister subdevices */
 369         list_for_each_entry_safe(subdev, sd, &device->active, list) {
 370                 /*
 371                  * host1x_subdev_unregister() will remove the client from
 372                  * any lists, so we'll need to manually add it back to the
 373                  * list of idle clients.
 374                  *
 375                  * XXX: Alternatively, perhaps don't remove the client from
 376                  * any lists in host1x_subdev_unregister() and instead do
 377                  * that explicitly from host1x_unregister_client()?
 378                  */
 379                 client = subdev->client;
 380
 381                 __host1x_subdev_unregister(device, subdev);
 382
 383                 /* add the client to the list of idle clients */
 384                 mutex_lock(&clients_lock);
 385                 list_add_tail(&client->list, &clients);
 386                 mutex_unlock(&clients_lock);
 387         }
 388
 389         /* remove subdevices */
 390         list_for_each_entry_safe(subdev, sd, &device->subdevs, list)
 391                 host1x_subdev_del(subdev);
 392
 393         mutex_unlock(&device->subdevs_lock);
 394
 395         /* move clients to idle list */
 396         mutex_lock(&clients_lock);
 397         mutex_lock(&device->clients_lock);
 398
 399         list_for_each_entry_safe(client, cl, &device->clients, list)
 400                 list_move_tail(&client->list, &clients);
 401
 402         mutex_unlock(&device->clients_lock);
 403         mutex_unlock(&clients_lock);
 404
 405         /* finally remove the device */
 406         list_del_init(&device->list);
 407 }
 408
 409 static void host1x_device_release(struct device *dev)
 410 {
 411         struct host1x_device *device = to_host1x_device(dev);
 412
 413         __host1x_device_del(device);
 414         kfree(device);
 415 }
 416
 417 static int host1x_device_add(struct host1x *host1x,
 418                              struct host1x_driver *driver)
 419 {
 420         struct host1x_client *client, *tmp;
 421         struct host1x_subdev *subdev;
 422         struct host1x_device *device;
 423         int err;
 424
 425         device = kzalloc(sizeof(*device), GFP_KERNEL);
 426         if (!device)
 427                 return -ENOMEM;
 428
 429         device_initialize(&device->dev);
 430
 431         mutex_init(&device->subdevs_lock);
 432         INIT_LIST_HEAD(&device->subdevs);
 433         INIT_LIST_HEAD(&device->active);
 434         mutex_init(&device->clients_lock);
 435         INIT_LIST_HEAD(&device->clients);
 436         INIT_LIST_HEAD(&device->list);
 437         device->driver = driver;
 438
 439         device->dev.coherent_dma_mask = host1x->dev->coherent_dma_mask;
 440         device->dev.dma_mask = &device->dev.coherent_dma_mask;
 441         dev_set_name(&device->dev, "%s", driver->driver.name);
 442         device->dev.release = host1x_device_release;
 443         device->dev.bus = &host1x_bus_type;
 444         device->dev.parent = host1x->dev;
 445
 446         of_dma_configure(&device->dev, host1x->dev->of_node, true);
 447
 448         device->dev.dma_parms = &device->dma_parms;
 449         dma_set_max_seg_size(&device->dev, UINT_MAX);
 450
 451         err = host1x_device_parse_dt(device, driver);
 452         if (err < 0) {
 453                 kfree(device);
 454                 return err;
 455         }
 456
 457         list_add_tail(&device->list, &host1x->devices);
 458
 459         mutex_lock(&clients_lock);
 460
 461         list_for_each_entry_safe(client, tmp, &clients, list) {
 462                 list_for_each_entry(subdev, &device->subdevs, list) {
 463                         if (subdev->np == client->dev->of_node) {
 464                                 host1x_subdev_register(device, subdev, client);
 465                                 break;
 466                         }
 467                 }
 468         }
 469
 470         mutex_unlock(&clients_lock);
 471
 472         return 0;
 473 }
 474
 475 /*
 476  * Removes a device by first unregistering any subdevices and then removing
 477  * itself from the list of devices.
 478  *
 479  * This function must be called with the host1x->devices_lock held.
 480  */
 481 static void host1x_device_del(struct host1x *host1x,
 482                               struct host1x_device *device)
 483 {
 484         if (device->registered) {
 485                 device->registered = false;
 486                 device_del(&device->dev);
 487         }
 488
 489         put_device(&device->dev);
 490 }
 491
 492 static void host1x_attach_driver(struct host1x *host1x,
 493                                  struct host1x_driver *driver)
 494 {
 495         struct host1x_device *device;
 496         int err;
 497
 498         mutex_lock(&host1x->devices_lock);
 499
 500         list_for_each_entry(device, &host1x->devices, list) {
 501                 if (device->driver == driver) {
 502                         mutex_unlock(&host1x->devices_lock);
 503                         return;
 504                 }
 505         }
 506
 507         err = host1x_device_add(host1x, driver);
 508         if (err < 0)
 509                 dev_err(host1x->dev, "failed to allocate device: %d\n", err);
 510
 511         mutex_unlock(&host1x->devices_lock);
 512 }
 513
 514 static void host1x_detach_driver(struct host1x *host1x,
 515                                  struct host1x_driver *driver)
 516 {
 517         struct host1x_device *device, *tmp;
 518
 519         mutex_lock(&host1x->devices_lock);
 520
 521         list_for_each_entry_safe(device, tmp, &host1x->devices, list)
 522                 if (device->driver == driver)
 523                         host1x_device_del(host1x, device);
 524
 525         mutex_unlock(&host1x->devices_lock);
 526 }
 527
 528 static int host1x_devices_show(struct seq_file *s, void *data)
 529 {
 530         struct host1x *host1x = s->private;
 531         struct host1x_device *device;
 532
 533         mutex_lock(&host1x->devices_lock);
 534
 535         list_for_each_entry(device, &host1x->devices, list) {
 536                 struct host1x_subdev *subdev;
 537
 538                 seq_printf(s, "%s\n", dev_name(&device->dev));
 539
 540                 mutex_lock(&device->subdevs_lock);
 541
 542                 list_for_each_entry(subdev, &device->active, list)
 543                         seq_printf(s, "  %pOFf: %s\n", subdev->np,
 544                                    dev_name(subdev->client->dev));
 545
 546                 list_for_each_entry(subdev, &device->subdevs, list)
 547                         seq_printf(s, "  %pOFf:\n", subdev->np);
 548
 549                 mutex_unlock(&device->subdevs_lock);
 550         }
 551
 552         mutex_unlock(&host1x->devices_lock);
 553
 554         return 0;
 555 }
 556 DEFINE_SHOW_ATTRIBUTE(host1x_devices);
 557
 558 /**
 559  * host1x_register() - register a host1x controller
 560  * @host1x: host1x controller
 561  *
 562  * The host1x controller driver uses this to register a host1x controller with
 563  * the infrastructure. Note that all Tegra SoC generations have only ever come
 564  * with a single host1x instance, so this function is somewhat academic.
 565  */
 566 int host1x_register(struct host1x *host1x)
 567 {
 568         struct host1x_driver *driver;
 569
 570         mutex_lock(&devices_lock);
 571         list_add_tail(&host1x->list, &devices);
 572         mutex_unlock(&devices_lock);
 573
 574         mutex_lock(&drivers_lock);
 575
 576         list_for_each_entry(driver, &drivers, list)
 577                 host1x_attach_driver(host1x, driver);
 578
 579         mutex_unlock(&drivers_lock);
 580
 581         debugfs_create_file("devices", S_IRUGO, host1x->debugfs, host1x,
 582                             &host1x_devices_fops);
 583
 584         return 0;
 585 }
 586
 587 /**
 588  * host1x_unregister() - unregister a host1x controller
 589  * @host1x: host1x controller
 590  *
 591  * The host1x controller driver uses this to remove a host1x controller from
 592  * the infrastructure.
 593  */
 594 int host1x_unregister(struct host1x *host1x)
 595 {
 596         struct host1x_driver *driver;
 597
 598         mutex_lock(&drivers_lock);
 599
 600         list_for_each_entry(driver, &drivers, list)
 601                 host1x_detach_driver(host1x, driver);
 602
 603         mutex_unlock(&drivers_lock);
 604
 605         mutex_lock(&devices_lock);
 606         list_del_init(&host1x->list);
 607         mutex_unlock(&devices_lock);
 608
 609         return 0;
 610 }
 611
 612 static int host1x_device_probe(struct device *dev)
 613 {
 614         struct host1x_driver *driver = to_host1x_driver(dev->driver);
 615         struct host1x_device *device = to_host1x_device(dev);
 616
 617         if (driver->probe)
 618                 return driver->probe(device);
 619
 620         return 0;
 621 }
 622
 623 static int host1x_device_remove(struct device *dev)
 624 {
 625         struct host1x_driver *driver = to_host1x_driver(dev->driver);
 626         struct host1x_device *device = to_host1x_device(dev);
 627
 628         if (driver->remove)
 629                 return driver->remove(device);
 630
 631         return 0;
 632 }
 633
 634 static void host1x_device_shutdown(struct device *dev)
 635 {
 636         struct host1x_driver *driver = to_host1x_driver(dev->driver);
 637         struct host1x_device *device = to_host1x_device(dev);
 638
 639         if (driver->shutdown)
 640                 driver->shutdown(device);
 641 }
 642
 643 /**
 644  * host1x_driver_register_full() - register a host1x driver
 645  * @driver: host1x driver
 646  * @owner: owner module
 647  *
 648  * Drivers for host1x logical devices call this function to register a driver
 649  * with the infrastructure. Note that since these drive logical devices, the
 650  * registration of the driver actually triggers tho logical device creation.
 651  * A logical device will be created for each host1x instance.
 652  */
 653 int host1x_driver_register_full(struct host1x_driver *driver,
 654                                 struct module *owner)
 655 {
 656         struct host1x *host1x;
 657
 658         INIT_LIST_HEAD(&driver->list);
 659
 660         mutex_lock(&drivers_lock);
 661         list_add_tail(&driver->list, &drivers);
 662         mutex_unlock(&drivers_lock);
 663
 664         mutex_lock(&devices_lock);
 665
 666         list_for_each_entry(host1x, &devices, list)
 667                 host1x_attach_driver(host1x, driver);
 668
 669         mutex_unlock(&devices_lock);
 670
 671         driver->driver.bus = &host1x_bus_type;
 672         driver->driver.owner = owner;
 673         driver->driver.probe = host1x_device_probe;
 674         driver->driver.remove = host1x_device_remove;
 675         driver->driver.shutdown = host1x_device_shutdown;
 676
 677         return driver_register(&driver->driver);
 678 }
 679 EXPORT_SYMBOL(host1x_driver_register_full);
 680
 681 /**
 682  * host1x_driver_unregister() - unregister a host1x driver
 683  * @driver: host1x driver
 684  *
 685  * Unbinds the driver from each of the host1x logical devices that it is
 686  * bound to, effectively removing the subsystem devices that they represent.
 687  */
 688 void host1x_driver_unregister(struct host1x_driver *driver)
 689 {
 690         struct host1x *host1x;
 691
 692         driver_unregister(&driver->driver);
 693
 694         mutex_lock(&devices_lock);
 695
 696         list_for_each_entry(host1x, &devices, list)
 697                 host1x_detach_driver(host1x, driver);
 698
 699         mutex_unlock(&devices_lock);
 700
 701         mutex_lock(&drivers_lock);
 702         list_del_init(&driver->list);
 703         mutex_unlock(&drivers_lock);
 704 }
 705 EXPORT_SYMBOL(host1x_driver_unregister);
 706
 707 /**
 708  * __host1x_client_register() - register a host1x client
 709  * @client: host1x client
 710  * @key: lock class key for the client-specific mutex
 711  *
 712  * Registers a host1x client with each host1x controller instance. Note that
 713  * each client will only match their parent host1x controller and will only be
 714  * associated with that instance. Once all clients have been registered with
 715  * their parent host1x controller, the infrastructure will set up the logical
 716  * device and call host1x_device_init(), which will in turn call each client's
 717  * &host1x_client_ops.init implementation.
 718  */
 719 int __host1x_client_register(struct host1x_client *client,
 720                              struct lock_class_key *key)
 721 {
 722         struct host1x *host1x;
 723         int err;
 724
 725         INIT_LIST_HEAD(&client->list);
 726         __mutex_init(&client->lock, "host1x client lock", key);
 727         client->usecount = 0;
 728
 729         mutex_lock(&devices_lock);
 730
 731         list_for_each_entry(host1x, &devices, list) {
 732                 err = host1x_add_client(host1x, client);
 733                 if (!err) {
 734                         mutex_unlock(&devices_lock);
 735                         return 0;
 736                 }
 737         }
 738
 739         mutex_unlock(&devices_lock);
 740
 741         mutex_lock(&clients_lock);
 742         list_add_tail(&client->list, &clients);
 743         mutex_unlock(&clients_lock);
 744
 745         return 0;
 746 }
 747 EXPORT_SYMBOL(__host1x_client_register);
 748
 749 /**
 750  * host1x_client_unregister() - unregister a host1x client
 751  * @client: host1x client
 752  *
 753  * Removes a host1x client from its host1x controller instance. If a logical
 754  * device has already been initialized, it will be torn down.
 755  */
 756 int host1x_client_unregister(struct host1x_client *client)
 757 {
 758         struct host1x_client *c;
 759         struct host1x *host1x;
 760         int err;
 761
 762         mutex_lock(&devices_lock);
 763
 764         list_for_each_entry(host1x, &devices, list) {
 765                 err = host1x_del_client(host1x, client);
 766                 if (!err) {
 767                         mutex_unlock(&devices_lock);
 768                         return 0;
 769                 }
 770         }
 771
 772         mutex_unlock(&devices_lock);
 773         mutex_lock(&clients_lock);
 774
 775         list_for_each_entry(c, &clients, list) {
 776                 if (c == client) {
 777                         list_del_init(&c->list);
 778                         break;
 779                 }
 780         }
 781
 782         mutex_unlock(&clients_lock);
 783
 784         return 0;
 785 }
 786 EXPORT_SYMBOL(host1x_client_unregister);
 787
 788 int host1x_client_suspend(struct host1x_client *client)
 789 {
 790         int err = 0;
 791
 792         mutex_lock(&client->lock);
 793
 794         if (client->usecount == 1) {
 795                 if (client->ops && client->ops->suspend) {
 796                         err = client->ops->suspend(client);
 797                         if (err < 0)
 798                                 goto unlock;
 799                 }
 800         }
 801
 802         client->usecount--;
 803         dev_dbg(client->dev, "use count: %u\n", client->usecount);
 804
 805         if (client->parent) {
 806                 err = host1x_client_suspend(client->parent);
 807                 if (err < 0)
 808                         goto resume;
 809         }
 810
 811         goto unlock;
 812
 813 resume:
 814         if (client->usecount == 0)
 815                 if (client->ops && client->ops->resume)
 816                         client->ops->resume(client);
 817
 818         client->usecount++;
 819 unlock:
 820         mutex_unlock(&client->lock);
 821         return err;
 822 }
 823 EXPORT_SYMBOL(host1x_client_suspend);
 824
 825 int host1x_client_resume(struct host1x_client *client)
 826 {
 827         int err = 0;
 828
 829         mutex_lock(&client->lock);
 830
 831         if (client->parent) {
 832                 err = host1x_client_resume(client->parent);
 833                 if (err < 0)
 834                         goto unlock;
 835         }
 836
 837         if (client->usecount == 0) {
 838                 if (client->ops && client->ops->resume) {
 839                         err = client->ops->resume(client);
 840                         if (err < 0)
 841                                 goto suspend;
 842                 }
 843         }
 844
 845         client->usecount++;
 846         dev_dbg(client->dev, "use count: %u\n", client->usecount);
 847
 848         goto unlock;
 849
 850 suspend:
 851         if (client->parent)
 852                 host1x_client_suspend(client->parent);
 853 unlock:
 854         mutex_unlock(&client->lock);
 855         return err;
 856 }
 857 EXPORT_SYMBOL(host1x_client_resume);