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