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