drivers/tty/serdev/core.c

   1 /*
   2  * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
   3  *
   4  * Based on drivers/spmi/spmi.c:
   5  * Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 and
   9  * only version 2 as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include <linux/errno.h>
  18 #include <linux/idr.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/of.h>
  22 #include <linux/of_device.h>
  23 #include <linux/serdev.h>
  24 #include <linux/slab.h>
  25
  26 static bool is_registered;
  27 static DEFINE_IDA(ctrl_ida);
  28
  29 static void serdev_device_release(struct device *dev)
  30 {
  31         struct serdev_device *serdev = to_serdev_device(dev);
  32         kfree(serdev);
  33 }
  34
  35 static const struct device_type serdev_device_type = {
  36         .release        = serdev_device_release,
  37 };
  38
  39 static void serdev_ctrl_release(struct device *dev)
  40 {
  41         struct serdev_controller *ctrl = to_serdev_controller(dev);
  42         ida_simple_remove(&ctrl_ida, ctrl->nr);
  43         kfree(ctrl);
  44 }
  45
  46 static const struct device_type serdev_ctrl_type = {
  47         .release        = serdev_ctrl_release,
  48 };
  49
  50 static int serdev_device_match(struct device *dev, struct device_driver *drv)
  51 {
  52         /* TODO: ACPI and platform matching */
  53         return of_driver_match_device(dev, drv);
  54 }
  55
  56 static int serdev_uevent(struct device *dev, struct kobj_uevent_env *env)
  57 {
  58         /* TODO: ACPI and platform modalias */
  59         return of_device_uevent_modalias(dev, env);
  60 }
  61
  62 /**
  63  * serdev_device_add() - add a device previously constructed via serdev_device_alloc()
  64  * @serdev:     serdev_device to be added
  65  */
  66 int serdev_device_add(struct serdev_device *serdev)
  67 {
  68         struct device *parent = serdev->dev.parent;
  69         int err;
  70
  71         dev_set_name(&serdev->dev, "%s-%d", dev_name(parent), serdev->nr);
  72
  73         err = device_add(&serdev->dev);
  74         if (err < 0) {
  75                 dev_err(&serdev->dev, "Can't add %s, status %d\n",
  76                         dev_name(&serdev->dev), err);
  77                 goto err_device_add;
  78         }
  79
  80         dev_dbg(&serdev->dev, "device %s registered\n", dev_name(&serdev->dev));
  81
  82 err_device_add:
  83         return err;
  84 }
  85 EXPORT_SYMBOL_GPL(serdev_device_add);
  86
  87 /**
  88  * serdev_device_remove(): remove an serdev device
  89  * @serdev:     serdev_device to be removed
  90  */
  91 void serdev_device_remove(struct serdev_device *serdev)
  92 {
  93         device_unregister(&serdev->dev);
  94 }
  95 EXPORT_SYMBOL_GPL(serdev_device_remove);
  96
  97 int serdev_device_open(struct serdev_device *serdev)
  98 {
  99         struct serdev_controller *ctrl = serdev->ctrl;
 100
 101         if (!ctrl || !ctrl->ops->open)
 102                 return -EINVAL;
 103
 104         return ctrl->ops->open(ctrl);
 105 }
 106 EXPORT_SYMBOL_GPL(serdev_device_open);
 107
 108 void serdev_device_close(struct serdev_device *serdev)
 109 {
 110         struct serdev_controller *ctrl = serdev->ctrl;
 111
 112         if (!ctrl || !ctrl->ops->close)
 113                 return;
 114
 115         ctrl->ops->close(ctrl);
 116 }
 117 EXPORT_SYMBOL_GPL(serdev_device_close);
 118
 119 void serdev_device_write_wakeup(struct serdev_device *serdev)
 120 {
 121         complete(&serdev->write_comp);
 122 }
 123 EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
 124
 125 int serdev_device_write_buf(struct serdev_device *serdev,
 126                             const unsigned char *buf, size_t count)
 127 {
 128         struct serdev_controller *ctrl = serdev->ctrl;
 129
 130         if (!ctrl || !ctrl->ops->write_buf)
 131                 return -EINVAL;
 132
 133         return ctrl->ops->write_buf(ctrl, buf, count);
 134 }
 135 EXPORT_SYMBOL_GPL(serdev_device_write_buf);
 136
 137 int serdev_device_write(struct serdev_device *serdev,
 138                         const unsigned char *buf, size_t count,
 139                         unsigned long timeout)
 140 {
 141         struct serdev_controller *ctrl = serdev->ctrl;
 142         int ret;
 143
 144         if (!ctrl || !ctrl->ops->write_buf ||
 145             (timeout && !serdev->ops->write_wakeup))
 146                 return -EINVAL;
 147
 148         mutex_lock(&serdev->write_lock);
 149         do {
 150                 reinit_completion(&serdev->write_comp);
 151
 152                 ret = ctrl->ops->write_buf(ctrl, buf, count);
 153                 if (ret < 0)
 154                         break;
 155
 156                 buf += ret;
 157                 count -= ret;
 158
 159         } while (count &&
 160                  (timeout = wait_for_completion_timeout(&serdev->write_comp,
 161                                                         timeout)));
 162         mutex_unlock(&serdev->write_lock);
 163         return ret < 0 ? ret : (count ? -ETIMEDOUT : 0);
 164 }
 165 EXPORT_SYMBOL_GPL(serdev_device_write);
 166
 167 void serdev_device_write_flush(struct serdev_device *serdev)
 168 {
 169         struct serdev_controller *ctrl = serdev->ctrl;
 170
 171         if (!ctrl || !ctrl->ops->write_flush)
 172                 return;
 173
 174         ctrl->ops->write_flush(ctrl);
 175 }
 176 EXPORT_SYMBOL_GPL(serdev_device_write_flush);
 177
 178 int serdev_device_write_room(struct serdev_device *serdev)
 179 {
 180         struct serdev_controller *ctrl = serdev->ctrl;
 181
 182         if (!ctrl || !ctrl->ops->write_room)
 183                 return 0;
 184
 185         return serdev->ctrl->ops->write_room(ctrl);
 186 }
 187 EXPORT_SYMBOL_GPL(serdev_device_write_room);
 188
 189 unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned int speed)
 190 {
 191         struct serdev_controller *ctrl = serdev->ctrl;
 192
 193         if (!ctrl || !ctrl->ops->set_baudrate)
 194                 return 0;
 195
 196         return ctrl->ops->set_baudrate(ctrl, speed);
 197
 198 }
 199 EXPORT_SYMBOL_GPL(serdev_device_set_baudrate);
 200
 201 void serdev_device_set_flow_control(struct serdev_device *serdev, bool enable)
 202 {
 203         struct serdev_controller *ctrl = serdev->ctrl;
 204
 205         if (!ctrl || !ctrl->ops->set_flow_control)
 206                 return;
 207
 208         ctrl->ops->set_flow_control(ctrl, enable);
 209 }
 210 EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
 211
 212 void serdev_device_wait_until_sent(struct serdev_device *serdev, long timeout)
 213 {
 214         struct serdev_controller *ctrl = serdev->ctrl;
 215
 216         if (!ctrl || !ctrl->ops->wait_until_sent)
 217                 return;
 218
 219         ctrl->ops->wait_until_sent(ctrl, timeout);
 220 }
 221 EXPORT_SYMBOL_GPL(serdev_device_wait_until_sent);
 222
 223 int serdev_device_get_tiocm(struct serdev_device *serdev)
 224 {
 225         struct serdev_controller *ctrl = serdev->ctrl;
 226
 227         if (!ctrl || !ctrl->ops->get_tiocm)
 228                 return -ENOTSUPP;
 229
 230         return ctrl->ops->get_tiocm(ctrl);
 231 }
 232 EXPORT_SYMBOL_GPL(serdev_device_get_tiocm);
 233
 234 int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
 235 {
 236         struct serdev_controller *ctrl = serdev->ctrl;
 237
 238         if (!ctrl || !ctrl->ops->set_tiocm)
 239                 return -ENOTSUPP;
 240
 241         return ctrl->ops->set_tiocm(ctrl, set, clear);
 242 }
 243 EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
 244
 245 static int serdev_drv_probe(struct device *dev)
 246 {
 247         const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 248
 249         return sdrv->probe(to_serdev_device(dev));
 250 }
 251
 252 static int serdev_drv_remove(struct device *dev)
 253 {
 254         const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 255
 256         sdrv->remove(to_serdev_device(dev));
 257         return 0;
 258 }
 259
 260 static ssize_t modalias_show(struct device *dev,
 261                              struct device_attribute *attr, char *buf)
 262 {
 263         return of_device_modalias(dev, buf, PAGE_SIZE);
 264 }
 265 DEVICE_ATTR_RO(modalias);
 266
 267 static struct attribute *serdev_device_attrs[] = {
 268         &dev_attr_modalias.attr,
 269         NULL,
 270 };
 271 ATTRIBUTE_GROUPS(serdev_device);
 272
 273 static struct bus_type serdev_bus_type = {
 274         .name           = "serial",
 275         .match          = serdev_device_match,
 276         .probe          = serdev_drv_probe,
 277         .remove         = serdev_drv_remove,
 278         .uevent         = serdev_uevent,
 279         .dev_groups     = serdev_device_groups,
 280 };
 281
 282 /**
 283  * serdev_controller_alloc() - Allocate a new serdev device
 284  * @ctrl:       associated controller
 285  *
 286  * Caller is responsible for either calling serdev_device_add() to add the
 287  * newly allocated controller, or calling serdev_device_put() to discard it.
 288  */
 289 struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
 290 {
 291         struct serdev_device *serdev;
 292
 293         serdev = kzalloc(sizeof(*serdev), GFP_KERNEL);
 294         if (!serdev)
 295                 return NULL;
 296
 297         serdev->ctrl = ctrl;
 298         ctrl->serdev = serdev;
 299         device_initialize(&serdev->dev);
 300         serdev->dev.parent = &ctrl->dev;
 301         serdev->dev.bus = &serdev_bus_type;
 302         serdev->dev.type = &serdev_device_type;
 303         init_completion(&serdev->write_comp);
 304         mutex_init(&serdev->write_lock);
 305         return serdev;
 306 }
 307 EXPORT_SYMBOL_GPL(serdev_device_alloc);
 308
 309 /**
 310  * serdev_controller_alloc() - Allocate a new serdev controller
 311  * @parent:     parent device
 312  * @size:       size of private data
 313  *
 314  * Caller is responsible for either calling serdev_controller_add() to add the
 315  * newly allocated controller, or calling serdev_controller_put() to discard it.
 316  * The allocated private data region may be accessed via
 317  * serdev_controller_get_drvdata()
 318  */
 319 struct serdev_controller *serdev_controller_alloc(struct device *parent,
 320                                               size_t size)
 321 {
 322         struct serdev_controller *ctrl;
 323         int id;
 324
 325         if (WARN_ON(!parent))
 326                 return NULL;
 327
 328         ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
 329         if (!ctrl)
 330                 return NULL;
 331
 332         device_initialize(&ctrl->dev);
 333         ctrl->dev.type = &serdev_ctrl_type;
 334         ctrl->dev.bus = &serdev_bus_type;
 335         ctrl->dev.parent = parent;
 336         ctrl->dev.of_node = parent->of_node;
 337         serdev_controller_set_drvdata(ctrl, &ctrl[1]);
 338
 339         id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
 340         if (id < 0) {
 341                 dev_err(parent,
 342                         "unable to allocate serdev controller identifier.\n");
 343                 serdev_controller_put(ctrl);
 344                 return NULL;
 345         }
 346
 347         ctrl->nr = id;
 348         dev_set_name(&ctrl->dev, "serial%d", id);
 349
 350         dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
 351         return ctrl;
 352 }
 353 EXPORT_SYMBOL_GPL(serdev_controller_alloc);
 354
 355 static int of_serdev_register_devices(struct serdev_controller *ctrl)
 356 {
 357         struct device_node *node;
 358         struct serdev_device *serdev = NULL;
 359         int err;
 360         bool found = false;
 361
 362         for_each_available_child_of_node(ctrl->dev.of_node, node) {
 363                 if (!of_get_property(node, "compatible", NULL))
 364                         continue;
 365
 366                 dev_dbg(&ctrl->dev, "adding child %s\n", node->full_name);
 367
 368                 serdev = serdev_device_alloc(ctrl);
 369                 if (!serdev)
 370                         continue;
 371
 372                 serdev->dev.of_node = node;
 373
 374                 err = serdev_device_add(serdev);
 375                 if (err) {
 376                         dev_err(&serdev->dev,
 377                                 "failure adding device. status %d\n", err);
 378                         serdev_device_put(serdev);
 379                 } else
 380                         found = true;
 381         }
 382         if (!found)
 383                 return -ENODEV;
 384
 385         return 0;
 386 }
 387
 388 /**
 389  * serdev_controller_add() - Add an serdev controller
 390  * @ctrl:       controller to be registered.
 391  *
 392  * Register a controller previously allocated via serdev_controller_alloc() with
 393  * the serdev core.
 394  */
 395 int serdev_controller_add(struct serdev_controller *ctrl)
 396 {
 397         int ret;
 398
 399         /* Can't register until after driver model init */
 400         if (WARN_ON(!is_registered))
 401                 return -EAGAIN;
 402
 403         ret = device_add(&ctrl->dev);
 404         if (ret)
 405                 return ret;
 406
 407         ret = of_serdev_register_devices(ctrl);
 408         if (ret)
 409                 goto out_dev_del;
 410
 411         dev_dbg(&ctrl->dev, "serdev%d registered: dev:%p\n",
 412                 ctrl->nr, &ctrl->dev);
 413         return 0;
 414
 415 out_dev_del:
 416         device_del(&ctrl->dev);
 417         return ret;
 418 };
 419 EXPORT_SYMBOL_GPL(serdev_controller_add);
 420
 421 /* Remove a device associated with a controller */
 422 static int serdev_remove_device(struct device *dev, void *data)
 423 {
 424         struct serdev_device *serdev = to_serdev_device(dev);
 425         if (dev->type == &serdev_device_type)
 426                 serdev_device_remove(serdev);
 427         return 0;
 428 }
 429
 430 /**
 431  * serdev_controller_remove(): remove an serdev controller
 432  * @ctrl:       controller to remove
 433  *
 434  * Remove a serdev controller.  Caller is responsible for calling
 435  * serdev_controller_put() to discard the allocated controller.
 436  */
 437 void serdev_controller_remove(struct serdev_controller *ctrl)
 438 {
 439         int dummy;
 440
 441         if (!ctrl)
 442                 return;
 443
 444         dummy = device_for_each_child(&ctrl->dev, NULL,
 445                                       serdev_remove_device);
 446         device_del(&ctrl->dev);
 447 }
 448 EXPORT_SYMBOL_GPL(serdev_controller_remove);
 449
 450 /**
 451  * serdev_driver_register() - Register client driver with serdev core
 452  * @sdrv:       client driver to be associated with client-device.
 453  *
 454  * This API will register the client driver with the serdev framework.
 455  * It is typically called from the driver's module-init function.
 456  */
 457 int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct module *owner)
 458 {
 459         sdrv->driver.bus = &serdev_bus_type;
 460         sdrv->driver.owner = owner;
 461
 462         /* force drivers to async probe so I/O is possible in probe */
 463         sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
 464
 465         return driver_register(&sdrv->driver);
 466 }
 467 EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
 468
 469 static void __exit serdev_exit(void)
 470 {
 471         bus_unregister(&serdev_bus_type);
 472 }
 473 module_exit(serdev_exit);
 474
 475 static int __init serdev_init(void)
 476 {
 477         int ret;
 478
 479         ret = bus_register(&serdev_bus_type);
 480         if (ret)
 481                 return ret;
 482
 483         is_registered = true;
 484         return 0;
 485 }
 486 /* Must be before serial drivers register */
 487 postcore_initcall(serdev_init);
 488
 489 MODULE_AUTHOR("Rob Herring <robh@kernel.org>");
 490 MODULE_LICENSE("GPL v2");
 491 MODULE_DESCRIPTION("Serial attached device bus");