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(struct serdev_device *serdev,
 126                         const unsigned char *buf, size_t count,
 127                         unsigned long timeout)
 128 {
 129         struct serdev_controller *ctrl = serdev->ctrl;
 130         int ret;
 131
 132         if (!ctrl || !ctrl->ops->write_buf ||
 133             (timeout && !serdev->ops->write_wakeup))
 134                 return -EINVAL;
 135
 136         mutex_lock(&serdev->write_lock);
 137         do {
 138                 reinit_completion(&serdev->write_comp);
 139
 140                 ret = ctrl->ops->write_buf(ctrl, buf, count);
 141                 if (ret < 0)
 142                         break;
 143
 144                 buf += ret;
 145                 count -= ret;
 146
 147         } while (count &&
 148                  (timeout = wait_for_completion_timeout(&serdev->write_comp,
 149                                                         timeout)));
 150         mutex_unlock(&serdev->write_lock);
 151         return ret < 0 ? ret : (count ? -ETIMEDOUT : 0);
 152 }
 153 EXPORT_SYMBOL_GPL(serdev_device_write);
 154
 155 void serdev_device_write_flush(struct serdev_device *serdev)
 156 {
 157         struct serdev_controller *ctrl = serdev->ctrl;
 158
 159         if (!ctrl || !ctrl->ops->write_flush)
 160                 return;
 161
 162         ctrl->ops->write_flush(ctrl);
 163 }
 164 EXPORT_SYMBOL_GPL(serdev_device_write_flush);
 165
 166 int serdev_device_write_room(struct serdev_device *serdev)
 167 {
 168         struct serdev_controller *ctrl = serdev->ctrl;
 169
 170         if (!ctrl || !ctrl->ops->write_room)
 171                 return 0;
 172
 173         return serdev->ctrl->ops->write_room(ctrl);
 174 }
 175 EXPORT_SYMBOL_GPL(serdev_device_write_room);
 176
 177 unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned int speed)
 178 {
 179         struct serdev_controller *ctrl = serdev->ctrl;
 180
 181         if (!ctrl || !ctrl->ops->set_baudrate)
 182                 return 0;
 183
 184         return ctrl->ops->set_baudrate(ctrl, speed);
 185
 186 }
 187 EXPORT_SYMBOL_GPL(serdev_device_set_baudrate);
 188
 189 void serdev_device_set_flow_control(struct serdev_device *serdev, bool enable)
 190 {
 191         struct serdev_controller *ctrl = serdev->ctrl;
 192
 193         if (!ctrl || !ctrl->ops->set_flow_control)
 194                 return;
 195
 196         ctrl->ops->set_flow_control(ctrl, enable);
 197 }
 198 EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
 199
 200 void serdev_device_wait_until_sent(struct serdev_device *serdev, long timeout)
 201 {
 202         struct serdev_controller *ctrl = serdev->ctrl;
 203
 204         if (!ctrl || !ctrl->ops->wait_until_sent)
 205                 return;
 206
 207         ctrl->ops->wait_until_sent(ctrl, timeout);
 208 }
 209 EXPORT_SYMBOL_GPL(serdev_device_wait_until_sent);
 210
 211 int serdev_device_get_tiocm(struct serdev_device *serdev)
 212 {
 213         struct serdev_controller *ctrl = serdev->ctrl;
 214
 215         if (!ctrl || !ctrl->ops->get_tiocm)
 216                 return -ENOTSUPP;
 217
 218         return ctrl->ops->get_tiocm(ctrl);
 219 }
 220 EXPORT_SYMBOL_GPL(serdev_device_get_tiocm);
 221
 222 int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
 223 {
 224         struct serdev_controller *ctrl = serdev->ctrl;
 225
 226         if (!ctrl || !ctrl->ops->set_tiocm)
 227                 return -ENOTSUPP;
 228
 229         return ctrl->ops->set_tiocm(ctrl, set, clear);
 230 }
 231 EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
 232
 233 static int serdev_drv_probe(struct device *dev)
 234 {
 235         const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 236
 237         return sdrv->probe(to_serdev_device(dev));
 238 }
 239
 240 static int serdev_drv_remove(struct device *dev)
 241 {
 242         const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 243
 244         sdrv->remove(to_serdev_device(dev));
 245         return 0;
 246 }
 247
 248 static ssize_t modalias_show(struct device *dev,
 249                              struct device_attribute *attr, char *buf)
 250 {
 251         return of_device_modalias(dev, buf, PAGE_SIZE);
 252 }
 253 DEVICE_ATTR_RO(modalias);
 254
 255 static struct attribute *serdev_device_attrs[] = {
 256         &dev_attr_modalias.attr,
 257         NULL,
 258 };
 259 ATTRIBUTE_GROUPS(serdev_device);
 260
 261 static struct bus_type serdev_bus_type = {
 262         .name           = "serial",
 263         .match          = serdev_device_match,
 264         .probe          = serdev_drv_probe,
 265         .remove         = serdev_drv_remove,
 266         .uevent         = serdev_uevent,
 267         .dev_groups     = serdev_device_groups,
 268 };
 269
 270 /**
 271  * serdev_controller_alloc() - Allocate a new serdev device
 272  * @ctrl:       associated controller
 273  *
 274  * Caller is responsible for either calling serdev_device_add() to add the
 275  * newly allocated controller, or calling serdev_device_put() to discard it.
 276  */
 277 struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
 278 {
 279         struct serdev_device *serdev;
 280
 281         serdev = kzalloc(sizeof(*serdev), GFP_KERNEL);
 282         if (!serdev)
 283                 return NULL;
 284
 285         serdev->ctrl = ctrl;
 286         ctrl->serdev = serdev;
 287         device_initialize(&serdev->dev);
 288         serdev->dev.parent = &ctrl->dev;
 289         serdev->dev.bus = &serdev_bus_type;
 290         serdev->dev.type = &serdev_device_type;
 291         init_completion(&serdev->write_comp);
 292         mutex_init(&serdev->write_lock);
 293         return serdev;
 294 }
 295 EXPORT_SYMBOL_GPL(serdev_device_alloc);
 296
 297 /**
 298  * serdev_controller_alloc() - Allocate a new serdev controller
 299  * @parent:     parent device
 300  * @size:       size of private data
 301  *
 302  * Caller is responsible for either calling serdev_controller_add() to add the
 303  * newly allocated controller, or calling serdev_controller_put() to discard it.
 304  * The allocated private data region may be accessed via
 305  * serdev_controller_get_drvdata()
 306  */
 307 struct serdev_controller *serdev_controller_alloc(struct device *parent,
 308                                               size_t size)
 309 {
 310         struct serdev_controller *ctrl;
 311         int id;
 312
 313         if (WARN_ON(!parent))
 314                 return NULL;
 315
 316         ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
 317         if (!ctrl)
 318                 return NULL;
 319
 320         device_initialize(&ctrl->dev);
 321         ctrl->dev.type = &serdev_ctrl_type;
 322         ctrl->dev.bus = &serdev_bus_type;
 323         ctrl->dev.parent = parent;
 324         ctrl->dev.of_node = parent->of_node;
 325         serdev_controller_set_drvdata(ctrl, &ctrl[1]);
 326
 327         id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
 328         if (id < 0) {
 329                 dev_err(parent,
 330                         "unable to allocate serdev controller identifier.\n");
 331                 serdev_controller_put(ctrl);
 332                 return NULL;
 333         }
 334
 335         ctrl->nr = id;
 336         dev_set_name(&ctrl->dev, "serial%d", id);
 337
 338         dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
 339         return ctrl;
 340 }
 341 EXPORT_SYMBOL_GPL(serdev_controller_alloc);
 342
 343 static int of_serdev_register_devices(struct serdev_controller *ctrl)
 344 {
 345         struct device_node *node;
 346         struct serdev_device *serdev = NULL;
 347         int err;
 348         bool found = false;
 349
 350         for_each_available_child_of_node(ctrl->dev.of_node, node) {
 351                 if (!of_get_property(node, "compatible", NULL))
 352                         continue;
 353
 354                 dev_dbg(&ctrl->dev, "adding child %s\n", node->full_name);
 355
 356                 serdev = serdev_device_alloc(ctrl);
 357                 if (!serdev)
 358                         continue;
 359
 360                 serdev->dev.of_node = node;
 361
 362                 err = serdev_device_add(serdev);
 363                 if (err) {
 364                         dev_err(&serdev->dev,
 365                                 "failure adding device. status %d\n", err);
 366                         serdev_device_put(serdev);
 367                 } else
 368                         found = true;
 369         }
 370         if (!found)
 371                 return -ENODEV;
 372
 373         return 0;
 374 }
 375
 376 /**
 377  * serdev_controller_add() - Add an serdev controller
 378  * @ctrl:       controller to be registered.
 379  *
 380  * Register a controller previously allocated via serdev_controller_alloc() with
 381  * the serdev core.
 382  */
 383 int serdev_controller_add(struct serdev_controller *ctrl)
 384 {
 385         int ret;
 386
 387         /* Can't register until after driver model init */
 388         if (WARN_ON(!is_registered))
 389                 return -EAGAIN;
 390
 391         ret = device_add(&ctrl->dev);
 392         if (ret)
 393                 return ret;
 394
 395         ret = of_serdev_register_devices(ctrl);
 396         if (ret)
 397                 goto out_dev_del;
 398
 399         dev_dbg(&ctrl->dev, "serdev%d registered: dev:%p\n",
 400                 ctrl->nr, &ctrl->dev);
 401         return 0;
 402
 403 out_dev_del:
 404         device_del(&ctrl->dev);
 405         return ret;
 406 };
 407 EXPORT_SYMBOL_GPL(serdev_controller_add);
 408
 409 /* Remove a device associated with a controller */
 410 static int serdev_remove_device(struct device *dev, void *data)
 411 {
 412         struct serdev_device *serdev = to_serdev_device(dev);
 413         if (dev->type == &serdev_device_type)
 414                 serdev_device_remove(serdev);
 415         return 0;
 416 }
 417
 418 /**
 419  * serdev_controller_remove(): remove an serdev controller
 420  * @ctrl:       controller to remove
 421  *
 422  * Remove a serdev controller.  Caller is responsible for calling
 423  * serdev_controller_put() to discard the allocated controller.
 424  */
 425 void serdev_controller_remove(struct serdev_controller *ctrl)
 426 {
 427         int dummy;
 428
 429         if (!ctrl)
 430                 return;
 431
 432         dummy = device_for_each_child(&ctrl->dev, NULL,
 433                                       serdev_remove_device);
 434         device_del(&ctrl->dev);
 435 }
 436 EXPORT_SYMBOL_GPL(serdev_controller_remove);
 437
 438 /**
 439  * serdev_driver_register() - Register client driver with serdev core
 440  * @sdrv:       client driver to be associated with client-device.
 441  *
 442  * This API will register the client driver with the serdev framework.
 443  * It is typically called from the driver's module-init function.
 444  */
 445 int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct module *owner)
 446 {
 447         sdrv->driver.bus = &serdev_bus_type;
 448         sdrv->driver.owner = owner;
 449
 450         /* force drivers to async probe so I/O is possible in probe */
 451         sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
 452
 453         return driver_register(&sdrv->driver);
 454 }
 455 EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
 456
 457 static void __exit serdev_exit(void)
 458 {
 459         bus_unregister(&serdev_bus_type);
 460 }
 461 module_exit(serdev_exit);
 462
 463 static int __init serdev_init(void)
 464 {
 465         int ret;
 466
 467         ret = bus_register(&serdev_bus_type);
 468         if (ret)
 469                 return ret;
 470
 471         is_registered = true;
 472         return 0;
 473 }
 474 /* Must be before serial drivers register */
 475 postcore_initcall(serdev_init);
 476
 477 MODULE_AUTHOR("Rob Herring <robh@kernel.org>");
 478 MODULE_LICENSE("GPL v2");
 479 MODULE_DESCRIPTION("Serial attached device bus");