drivers/tty/serdev/core.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
   4  *
   5  * Based on drivers/spmi/spmi.c:
   6  * Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
   7  */
   8
   9 #include <linux/acpi.h>
  10 #include <linux/errno.h>
  11 #include <linux/idr.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/of.h>
  15 #include <linux/of_device.h>
  16 #include <linux/pm_domain.h>
  17 #include <linux/pm_runtime.h>
  18 #include <linux/serdev.h>
  19 #include <linux/slab.h>
  20
  21 static bool is_registered;
  22 static DEFINE_IDA(ctrl_ida);
  23
  24 static ssize_t modalias_show(struct device *dev,
  25                              struct device_attribute *attr, char *buf)
  26 {
  27         int len;
  28
  29         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  30         if (len != -ENODEV)
  31                 return len;
  32
  33         return of_device_modalias(dev, buf, PAGE_SIZE);
  34 }
  35 static DEVICE_ATTR_RO(modalias);
  36
  37 static struct attribute *serdev_device_attrs[] = {
  38         &dev_attr_modalias.attr,
  39         NULL,
  40 };
  41 ATTRIBUTE_GROUPS(serdev_device);
  42
  43 static int serdev_device_uevent(struct device *dev, struct kobj_uevent_env *env)
  44 {
  45         int rc;
  46
  47         /* TODO: platform modalias */
  48
  49         rc = acpi_device_uevent_modalias(dev, env);
  50         if (rc != -ENODEV)
  51                 return rc;
  52
  53         return of_device_uevent_modalias(dev, env);
  54 }
  55
  56 static void serdev_device_release(struct device *dev)
  57 {
  58         struct serdev_device *serdev = to_serdev_device(dev);
  59         kfree(serdev);
  60 }
  61
  62 static const struct device_type serdev_device_type = {
  63         .groups         = serdev_device_groups,
  64         .uevent         = serdev_device_uevent,
  65         .release        = serdev_device_release,
  66 };
  67
  68 static bool is_serdev_device(const struct device *dev)
  69 {
  70         return dev->type == &serdev_device_type;
  71 }
  72
  73 static void serdev_ctrl_release(struct device *dev)
  74 {
  75         struct serdev_controller *ctrl = to_serdev_controller(dev);
  76         ida_simple_remove(&ctrl_ida, ctrl->nr);
  77         kfree(ctrl);
  78 }
  79
  80 static const struct device_type serdev_ctrl_type = {
  81         .release        = serdev_ctrl_release,
  82 };
  83
  84 static int serdev_device_match(struct device *dev, struct device_driver *drv)
  85 {
  86         if (!is_serdev_device(dev))
  87                 return 0;
  88
  89         /* TODO: platform matching */
  90         if (acpi_driver_match_device(dev, drv))
  91                 return 1;
  92
  93         return of_driver_match_device(dev, drv);
  94 }
  95
  96 /**
  97  * serdev_device_add() - add a device previously constructed via serdev_device_alloc()
  98  * @serdev:     serdev_device to be added
  99  */
 100 int serdev_device_add(struct serdev_device *serdev)
 101 {
 102         struct serdev_controller *ctrl = serdev->ctrl;
 103         struct device *parent = serdev->dev.parent;
 104         int err;
 105
 106         dev_set_name(&serdev->dev, "%s-%d", dev_name(parent), serdev->nr);
 107
 108         /* Only a single slave device is currently supported. */
 109         if (ctrl->serdev) {
 110                 dev_err(&serdev->dev, "controller busy\n");
 111                 return -EBUSY;
 112         }
 113         ctrl->serdev = serdev;
 114
 115         err = device_add(&serdev->dev);
 116         if (err < 0) {
 117                 dev_err(&serdev->dev, "Can't add %s, status %d\n",
 118                         dev_name(&serdev->dev), err);
 119                 goto err_clear_serdev;
 120         }
 121
 122         dev_dbg(&serdev->dev, "device %s registered\n", dev_name(&serdev->dev));
 123
 124         return 0;
 125
 126 err_clear_serdev:
 127         ctrl->serdev = NULL;
 128         return err;
 129 }
 130 EXPORT_SYMBOL_GPL(serdev_device_add);
 131
 132 /**
 133  * serdev_device_remove(): remove an serdev device
 134  * @serdev:     serdev_device to be removed
 135  */
 136 void serdev_device_remove(struct serdev_device *serdev)
 137 {
 138         struct serdev_controller *ctrl = serdev->ctrl;
 139
 140         device_unregister(&serdev->dev);
 141         ctrl->serdev = NULL;
 142 }
 143 EXPORT_SYMBOL_GPL(serdev_device_remove);
 144
 145 int serdev_device_open(struct serdev_device *serdev)
 146 {
 147         struct serdev_controller *ctrl = serdev->ctrl;
 148         int ret;
 149
 150         if (!ctrl || !ctrl->ops->open)
 151                 return -EINVAL;
 152
 153         ret = ctrl->ops->open(ctrl);
 154         if (ret)
 155                 return ret;
 156
 157         ret = pm_runtime_get_sync(&ctrl->dev);
 158         if (ret < 0) {
 159                 pm_runtime_put_noidle(&ctrl->dev);
 160                 goto err_close;
 161         }
 162
 163         return 0;
 164
 165 err_close:
 166         if (ctrl->ops->close)
 167                 ctrl->ops->close(ctrl);
 168
 169         return ret;
 170 }
 171 EXPORT_SYMBOL_GPL(serdev_device_open);
 172
 173 void serdev_device_close(struct serdev_device *serdev)
 174 {
 175         struct serdev_controller *ctrl = serdev->ctrl;
 176
 177         if (!ctrl || !ctrl->ops->close)
 178                 return;
 179
 180         pm_runtime_put(&ctrl->dev);
 181
 182         ctrl->ops->close(ctrl);
 183 }
 184 EXPORT_SYMBOL_GPL(serdev_device_close);
 185
 186 static void devm_serdev_device_release(struct device *dev, void *dr)
 187 {
 188         serdev_device_close(*(struct serdev_device **)dr);
 189 }
 190
 191 int devm_serdev_device_open(struct device *dev, struct serdev_device *serdev)
 192 {
 193         struct serdev_device **dr;
 194         int ret;
 195
 196         dr = devres_alloc(devm_serdev_device_release, sizeof(*dr), GFP_KERNEL);
 197         if (!dr)
 198                 return -ENOMEM;
 199
 200         ret = serdev_device_open(serdev);
 201         if (ret) {
 202                 devres_free(dr);
 203                 return ret;
 204         }
 205
 206         *dr = serdev;
 207         devres_add(dev, dr);
 208
 209         return 0;
 210 }
 211 EXPORT_SYMBOL_GPL(devm_serdev_device_open);
 212
 213 void serdev_device_write_wakeup(struct serdev_device *serdev)
 214 {
 215         complete(&serdev->write_comp);
 216 }
 217 EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
 218
 219 int serdev_device_write_buf(struct serdev_device *serdev,
 220                             const unsigned char *buf, size_t count)
 221 {
 222         struct serdev_controller *ctrl = serdev->ctrl;
 223
 224         if (!ctrl || !ctrl->ops->write_buf)
 225                 return -EINVAL;
 226
 227         return ctrl->ops->write_buf(ctrl, buf, count);
 228 }
 229 EXPORT_SYMBOL_GPL(serdev_device_write_buf);
 230
 231 int serdev_device_write(struct serdev_device *serdev,
 232                         const unsigned char *buf, size_t count,
 233                         unsigned long timeout)
 234 {
 235         struct serdev_controller *ctrl = serdev->ctrl;
 236         int ret;
 237
 238         if (!ctrl || !ctrl->ops->write_buf ||
 239             (timeout && !serdev->ops->write_wakeup))
 240                 return -EINVAL;
 241
 242         mutex_lock(&serdev->write_lock);
 243         do {
 244                 reinit_completion(&serdev->write_comp);
 245
 246                 ret = ctrl->ops->write_buf(ctrl, buf, count);
 247                 if (ret < 0)
 248                         break;
 249
 250                 buf += ret;
 251                 count -= ret;
 252
 253         } while (count &&
 254                  (timeout = wait_for_completion_timeout(&serdev->write_comp,
 255                                                         timeout)));
 256         mutex_unlock(&serdev->write_lock);
 257         return ret < 0 ? ret : (count ? -ETIMEDOUT : 0);
 258 }
 259 EXPORT_SYMBOL_GPL(serdev_device_write);
 260
 261 void serdev_device_write_flush(struct serdev_device *serdev)
 262 {
 263         struct serdev_controller *ctrl = serdev->ctrl;
 264
 265         if (!ctrl || !ctrl->ops->write_flush)
 266                 return;
 267
 268         ctrl->ops->write_flush(ctrl);
 269 }
 270 EXPORT_SYMBOL_GPL(serdev_device_write_flush);
 271
 272 int serdev_device_write_room(struct serdev_device *serdev)
 273 {
 274         struct serdev_controller *ctrl = serdev->ctrl;
 275
 276         if (!ctrl || !ctrl->ops->write_room)
 277                 return 0;
 278
 279         return serdev->ctrl->ops->write_room(ctrl);
 280 }
 281 EXPORT_SYMBOL_GPL(serdev_device_write_room);
 282
 283 unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned int speed)
 284 {
 285         struct serdev_controller *ctrl = serdev->ctrl;
 286
 287         if (!ctrl || !ctrl->ops->set_baudrate)
 288                 return 0;
 289
 290         return ctrl->ops->set_baudrate(ctrl, speed);
 291
 292 }
 293 EXPORT_SYMBOL_GPL(serdev_device_set_baudrate);
 294
 295 void serdev_device_set_flow_control(struct serdev_device *serdev, bool enable)
 296 {
 297         struct serdev_controller *ctrl = serdev->ctrl;
 298
 299         if (!ctrl || !ctrl->ops->set_flow_control)
 300                 return;
 301
 302         ctrl->ops->set_flow_control(ctrl, enable);
 303 }
 304 EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
 305
 306 int serdev_device_set_parity(struct serdev_device *serdev,
 307                              enum serdev_parity parity)
 308 {
 309         struct serdev_controller *ctrl = serdev->ctrl;
 310
 311         if (!ctrl || !ctrl->ops->set_parity)
 312                 return -ENOTSUPP;
 313
 314         return ctrl->ops->set_parity(ctrl, parity);
 315 }
 316 EXPORT_SYMBOL_GPL(serdev_device_set_parity);
 317
 318 void serdev_device_wait_until_sent(struct serdev_device *serdev, long timeout)
 319 {
 320         struct serdev_controller *ctrl = serdev->ctrl;
 321
 322         if (!ctrl || !ctrl->ops->wait_until_sent)
 323                 return;
 324
 325         ctrl->ops->wait_until_sent(ctrl, timeout);
 326 }
 327 EXPORT_SYMBOL_GPL(serdev_device_wait_until_sent);
 328
 329 int serdev_device_get_tiocm(struct serdev_device *serdev)
 330 {
 331         struct serdev_controller *ctrl = serdev->ctrl;
 332
 333         if (!ctrl || !ctrl->ops->get_tiocm)
 334                 return -ENOTSUPP;
 335
 336         return ctrl->ops->get_tiocm(ctrl);
 337 }
 338 EXPORT_SYMBOL_GPL(serdev_device_get_tiocm);
 339
 340 int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
 341 {
 342         struct serdev_controller *ctrl = serdev->ctrl;
 343
 344         if (!ctrl || !ctrl->ops->set_tiocm)
 345                 return -ENOTSUPP;
 346
 347         return ctrl->ops->set_tiocm(ctrl, set, clear);
 348 }
 349 EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
 350
 351 static int serdev_drv_probe(struct device *dev)
 352 {
 353         const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 354         int ret;
 355
 356         ret = dev_pm_domain_attach(dev, true);
 357         if (ret)
 358                 return ret;
 359
 360         ret = sdrv->probe(to_serdev_device(dev));
 361         if (ret)
 362                 dev_pm_domain_detach(dev, true);
 363
 364         return ret;
 365 }
 366
 367 static int serdev_drv_remove(struct device *dev)
 368 {
 369         const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 370         if (sdrv->remove)
 371                 sdrv->remove(to_serdev_device(dev));
 372
 373         dev_pm_domain_detach(dev, true);
 374
 375         return 0;
 376 }
 377
 378 static struct bus_type serdev_bus_type = {
 379         .name           = "serial",
 380         .match          = serdev_device_match,
 381         .probe          = serdev_drv_probe,
 382         .remove         = serdev_drv_remove,
 383 };
 384
 385 /**
 386  * serdev_device_alloc() - Allocate a new serdev device
 387  * @ctrl:       associated controller
 388  *
 389  * Caller is responsible for either calling serdev_device_add() to add the
 390  * newly allocated controller, or calling serdev_device_put() to discard it.
 391  */
 392 struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
 393 {
 394         struct serdev_device *serdev;
 395
 396         serdev = kzalloc(sizeof(*serdev), GFP_KERNEL);
 397         if (!serdev)
 398                 return NULL;
 399
 400         serdev->ctrl = ctrl;
 401         device_initialize(&serdev->dev);
 402         serdev->dev.parent = &ctrl->dev;
 403         serdev->dev.bus = &serdev_bus_type;
 404         serdev->dev.type = &serdev_device_type;
 405         init_completion(&serdev->write_comp);
 406         mutex_init(&serdev->write_lock);
 407         return serdev;
 408 }
 409 EXPORT_SYMBOL_GPL(serdev_device_alloc);
 410
 411 /**
 412  * serdev_controller_alloc() - Allocate a new serdev controller
 413  * @parent:     parent device
 414  * @size:       size of private data
 415  *
 416  * Caller is responsible for either calling serdev_controller_add() to add the
 417  * newly allocated controller, or calling serdev_controller_put() to discard it.
 418  * The allocated private data region may be accessed via
 419  * serdev_controller_get_drvdata()
 420  */
 421 struct serdev_controller *serdev_controller_alloc(struct device *parent,
 422                                               size_t size)
 423 {
 424         struct serdev_controller *ctrl;
 425         int id;
 426
 427         if (WARN_ON(!parent))
 428                 return NULL;
 429
 430         ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
 431         if (!ctrl)
 432                 return NULL;
 433
 434         id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
 435         if (id < 0) {
 436                 dev_err(parent,
 437                         "unable to allocate serdev controller identifier.\n");
 438                 goto err_free;
 439         }
 440
 441         ctrl->nr = id;
 442
 443         device_initialize(&ctrl->dev);
 444         ctrl->dev.type = &serdev_ctrl_type;
 445         ctrl->dev.bus = &serdev_bus_type;
 446         ctrl->dev.parent = parent;
 447         ctrl->dev.of_node = parent->of_node;
 448         serdev_controller_set_drvdata(ctrl, &ctrl[1]);
 449
 450         dev_set_name(&ctrl->dev, "serial%d", id);
 451
 452         pm_runtime_no_callbacks(&ctrl->dev);
 453         pm_suspend_ignore_children(&ctrl->dev, true);
 454
 455         dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
 456         return ctrl;
 457
 458 err_free:
 459         kfree(ctrl);
 460
 461         return NULL;
 462 }
 463 EXPORT_SYMBOL_GPL(serdev_controller_alloc);
 464
 465 static int of_serdev_register_devices(struct serdev_controller *ctrl)
 466 {
 467         struct device_node *node;
 468         struct serdev_device *serdev = NULL;
 469         int err;
 470         bool found = false;
 471
 472         for_each_available_child_of_node(ctrl->dev.of_node, node) {
 473                 if (!of_get_property(node, "compatible", NULL))
 474                         continue;
 475
 476                 dev_dbg(&ctrl->dev, "adding child %pOF\n", node);
 477
 478                 serdev = serdev_device_alloc(ctrl);
 479                 if (!serdev)
 480                         continue;
 481
 482                 serdev->dev.of_node = node;
 483
 484                 err = serdev_device_add(serdev);
 485                 if (err) {
 486                         dev_err(&serdev->dev,
 487                                 "failure adding device. status %d\n", err);
 488                         serdev_device_put(serdev);
 489                 } else
 490                         found = true;
 491         }
 492         if (!found)
 493                 return -ENODEV;
 494
 495         return 0;
 496 }
 497
 498 #ifdef CONFIG_ACPI
 499 static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl,
 500                                             struct acpi_device *adev)
 501 {
 502         struct serdev_device *serdev = NULL;
 503         int err;
 504
 505         if (acpi_bus_get_status(adev) || !adev->status.present ||
 506             acpi_device_enumerated(adev))
 507                 return AE_OK;
 508
 509         serdev = serdev_device_alloc(ctrl);
 510         if (!serdev) {
 511                 dev_err(&ctrl->dev, "failed to allocate serdev device for %s\n",
 512                         dev_name(&adev->dev));
 513                 return AE_NO_MEMORY;
 514         }
 515
 516         ACPI_COMPANION_SET(&serdev->dev, adev);
 517         acpi_device_set_enumerated(adev);
 518
 519         err = serdev_device_add(serdev);
 520         if (err) {
 521                 dev_err(&serdev->dev,
 522                         "failure adding ACPI serdev device. status %d\n", err);
 523                 serdev_device_put(serdev);
 524         }
 525
 526         return AE_OK;
 527 }
 528
 529 static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
 530                                        void *data, void **return_value)
 531 {
 532         struct serdev_controller *ctrl = data;
 533         struct acpi_device *adev;
 534
 535         if (acpi_bus_get_device(handle, &adev))
 536                 return AE_OK;
 537
 538         return acpi_serdev_register_device(ctrl, adev);
 539 }
 540
 541 static int acpi_serdev_register_devices(struct serdev_controller *ctrl)
 542 {
 543         acpi_status status;
 544         acpi_handle handle;
 545
 546         handle = ACPI_HANDLE(ctrl->dev.parent);
 547         if (!handle)
 548                 return -ENODEV;
 549
 550         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
 551                                      acpi_serdev_add_device, NULL, ctrl, NULL);
 552         if (ACPI_FAILURE(status))
 553                 dev_dbg(&ctrl->dev, "failed to enumerate serdev slaves\n");
 554
 555         if (!ctrl->serdev)
 556                 return -ENODEV;
 557
 558         return 0;
 559 }
 560 #else
 561 static inline int acpi_serdev_register_devices(struct serdev_controller *ctrl)
 562 {
 563         return -ENODEV;
 564 }
 565 #endif /* CONFIG_ACPI */
 566
 567 /**
 568  * serdev_controller_add() - Add an serdev controller
 569  * @ctrl:       controller to be registered.
 570  *
 571  * Register a controller previously allocated via serdev_controller_alloc() with
 572  * the serdev core.
 573  */
 574 int serdev_controller_add(struct serdev_controller *ctrl)
 575 {
 576         int ret_of, ret_acpi, ret;
 577
 578         /* Can't register until after driver model init */
 579         if (WARN_ON(!is_registered))
 580                 return -EAGAIN;
 581
 582         ret = device_add(&ctrl->dev);
 583         if (ret)
 584                 return ret;
 585
 586         pm_runtime_enable(&ctrl->dev);
 587
 588         ret_of = of_serdev_register_devices(ctrl);
 589         ret_acpi = acpi_serdev_register_devices(ctrl);
 590         if (ret_of && ret_acpi) {
 591                 dev_dbg(&ctrl->dev, "no devices registered: of:%d acpi:%d\n",
 592                         ret_of, ret_acpi);
 593                 ret = -ENODEV;
 594                 goto err_rpm_disable;
 595         }
 596
 597         dev_dbg(&ctrl->dev, "serdev%d registered: dev:%p\n",
 598                 ctrl->nr, &ctrl->dev);
 599         return 0;
 600
 601 err_rpm_disable:
 602         pm_runtime_disable(&ctrl->dev);
 603         device_del(&ctrl->dev);
 604         return ret;
 605 };
 606 EXPORT_SYMBOL_GPL(serdev_controller_add);
 607
 608 /* Remove a device associated with a controller */
 609 static int serdev_remove_device(struct device *dev, void *data)
 610 {
 611         struct serdev_device *serdev = to_serdev_device(dev);
 612         if (dev->type == &serdev_device_type)
 613                 serdev_device_remove(serdev);
 614         return 0;
 615 }
 616
 617 /**
 618  * serdev_controller_remove(): remove an serdev controller
 619  * @ctrl:       controller to remove
 620  *
 621  * Remove a serdev controller.  Caller is responsible for calling
 622  * serdev_controller_put() to discard the allocated controller.
 623  */
 624 void serdev_controller_remove(struct serdev_controller *ctrl)
 625 {
 626         int dummy;
 627
 628         if (!ctrl)
 629                 return;
 630
 631         dummy = device_for_each_child(&ctrl->dev, NULL,
 632                                       serdev_remove_device);
 633         pm_runtime_disable(&ctrl->dev);
 634         device_del(&ctrl->dev);
 635 }
 636 EXPORT_SYMBOL_GPL(serdev_controller_remove);
 637
 638 /**
 639  * serdev_driver_register() - Register client driver with serdev core
 640  * @sdrv:       client driver to be associated with client-device.
 641  *
 642  * This API will register the client driver with the serdev framework.
 643  * It is typically called from the driver's module-init function.
 644  */
 645 int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct module *owner)
 646 {
 647         sdrv->driver.bus = &serdev_bus_type;
 648         sdrv->driver.owner = owner;
 649
 650         /* force drivers to async probe so I/O is possible in probe */
 651         sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
 652
 653         return driver_register(&sdrv->driver);
 654 }
 655 EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
 656
 657 static void __exit serdev_exit(void)
 658 {
 659         bus_unregister(&serdev_bus_type);
 660         ida_destroy(&ctrl_ida);
 661 }
 662 module_exit(serdev_exit);
 663
 664 static int __init serdev_init(void)
 665 {
 666         int ret;
 667
 668         ret = bus_register(&serdev_bus_type);
 669         if (ret)
 670                 return ret;
 671
 672         is_registered = true;
 673         return 0;
 674 }
 675 /* Must be before serial drivers register */
 676 postcore_initcall(serdev_init);
 677
 678 MODULE_AUTHOR("Rob Herring <robh@kernel.org>");
 679 MODULE_LICENSE("GPL v2");
 680 MODULE_DESCRIPTION("Serial attached device bus");