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 serdev_controller *ctrl = serdev->ctrl;
  69         struct device *parent = serdev->dev.parent;
  70         int err;
  71
  72         dev_set_name(&serdev->dev, "%s-%d", dev_name(parent), serdev->nr);
  73
  74         /* Only a single slave device is currently supported. */
  75         if (ctrl->serdev) {
  76                 dev_err(&serdev->dev, "controller busy\n");
  77                 return -EBUSY;
  78         }
  79         ctrl->serdev = serdev;
  80
  81         err = device_add(&serdev->dev);
  82         if (err < 0) {
  83                 dev_err(&serdev->dev, "Can't add %s, status %d\n",
  84                         dev_name(&serdev->dev), err);
  85                 goto err_clear_serdev;
  86         }
  87
  88         dev_dbg(&serdev->dev, "device %s registered\n", dev_name(&serdev->dev));
  89
  90         return 0;
  91
  92 err_clear_serdev:
  93         ctrl->serdev = NULL;
  94         return err;
  95 }
  96 EXPORT_SYMBOL_GPL(serdev_device_add);
  97
  98 /**
  99  * serdev_device_remove(): remove an serdev device
 100  * @serdev:     serdev_device to be removed
 101  */
 102 void serdev_device_remove(struct serdev_device *serdev)
 103 {
 104         struct serdev_controller *ctrl = serdev->ctrl;
 105
 106         device_unregister(&serdev->dev);
 107         ctrl->serdev = NULL;
 108 }
 109 EXPORT_SYMBOL_GPL(serdev_device_remove);
 110
 111 int serdev_device_open(struct serdev_device *serdev)
 112 {
 113         struct serdev_controller *ctrl = serdev->ctrl;
 114
 115         if (!ctrl || !ctrl->ops->open)
 116                 return -EINVAL;
 117
 118         return ctrl->ops->open(ctrl);
 119 }
 120 EXPORT_SYMBOL_GPL(serdev_device_open);
 121
 122 void serdev_device_close(struct serdev_device *serdev)
 123 {
 124         struct serdev_controller *ctrl = serdev->ctrl;
 125
 126         if (!ctrl || !ctrl->ops->close)
 127                 return;
 128
 129         ctrl->ops->close(ctrl);
 130 }
 131 EXPORT_SYMBOL_GPL(serdev_device_close);
 132
 133 void serdev_device_write_wakeup(struct serdev_device *serdev)
 134 {
 135         complete(&serdev->write_comp);
 136 }
 137 EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
 138
 139 int serdev_device_write_buf(struct serdev_device *serdev,
 140                             const unsigned char *buf, size_t count)
 141 {
 142         struct serdev_controller *ctrl = serdev->ctrl;
 143
 144         if (!ctrl || !ctrl->ops->write_buf)
 145                 return -EINVAL;
 146
 147         return ctrl->ops->write_buf(ctrl, buf, count);
 148 }
 149 EXPORT_SYMBOL_GPL(serdev_device_write_buf);
 150
 151 int serdev_device_write(struct serdev_device *serdev,
 152                         const unsigned char *buf, size_t count,
 153                         unsigned long timeout)
 154 {
 155         struct serdev_controller *ctrl = serdev->ctrl;
 156         int ret;
 157
 158         if (!ctrl || !ctrl->ops->write_buf ||
 159             (timeout && !serdev->ops->write_wakeup))
 160                 return -EINVAL;
 161
 162         mutex_lock(&serdev->write_lock);
 163         do {
 164                 reinit_completion(&serdev->write_comp);
 165
 166                 ret = ctrl->ops->write_buf(ctrl, buf, count);
 167                 if (ret < 0)
 168                         break;
 169
 170                 buf += ret;
 171                 count -= ret;
 172
 173         } while (count &&
 174                  (timeout = wait_for_completion_timeout(&serdev->write_comp,
 175                                                         timeout)));
 176         mutex_unlock(&serdev->write_lock);
 177         return ret < 0 ? ret : (count ? -ETIMEDOUT : 0);
 178 }
 179 EXPORT_SYMBOL_GPL(serdev_device_write);
 180
 181 void serdev_device_write_flush(struct serdev_device *serdev)
 182 {
 183         struct serdev_controller *ctrl = serdev->ctrl;
 184
 185         if (!ctrl || !ctrl->ops->write_flush)
 186                 return;
 187
 188         ctrl->ops->write_flush(ctrl);
 189 }
 190 EXPORT_SYMBOL_GPL(serdev_device_write_flush);
 191
 192 int serdev_device_write_room(struct serdev_device *serdev)
 193 {
 194         struct serdev_controller *ctrl = serdev->ctrl;
 195
 196         if (!ctrl || !ctrl->ops->write_room)
 197                 return 0;
 198
 199         return serdev->ctrl->ops->write_room(ctrl);
 200 }
 201 EXPORT_SYMBOL_GPL(serdev_device_write_room);
 202
 203 unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned int speed)
 204 {
 205         struct serdev_controller *ctrl = serdev->ctrl;
 206
 207         if (!ctrl || !ctrl->ops->set_baudrate)
 208                 return 0;
 209
 210         return ctrl->ops->set_baudrate(ctrl, speed);
 211
 212 }
 213 EXPORT_SYMBOL_GPL(serdev_device_set_baudrate);
 214
 215 void serdev_device_set_flow_control(struct serdev_device *serdev, bool enable)
 216 {
 217         struct serdev_controller *ctrl = serdev->ctrl;
 218
 219         if (!ctrl || !ctrl->ops->set_flow_control)
 220                 return;
 221
 222         ctrl->ops->set_flow_control(ctrl, enable);
 223 }
 224 EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
 225
 226 void serdev_device_wait_until_sent(struct serdev_device *serdev, long timeout)
 227 {
 228         struct serdev_controller *ctrl = serdev->ctrl;
 229
 230         if (!ctrl || !ctrl->ops->wait_until_sent)
 231                 return;
 232
 233         ctrl->ops->wait_until_sent(ctrl, timeout);
 234 }
 235 EXPORT_SYMBOL_GPL(serdev_device_wait_until_sent);
 236
 237 int serdev_device_get_tiocm(struct serdev_device *serdev)
 238 {
 239         struct serdev_controller *ctrl = serdev->ctrl;
 240
 241         if (!ctrl || !ctrl->ops->get_tiocm)
 242                 return -ENOTSUPP;
 243
 244         return ctrl->ops->get_tiocm(ctrl);
 245 }
 246 EXPORT_SYMBOL_GPL(serdev_device_get_tiocm);
 247
 248 int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
 249 {
 250         struct serdev_controller *ctrl = serdev->ctrl;
 251
 252         if (!ctrl || !ctrl->ops->set_tiocm)
 253                 return -ENOTSUPP;
 254
 255         return ctrl->ops->set_tiocm(ctrl, set, clear);
 256 }
 257 EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
 258
 259 static int serdev_drv_probe(struct device *dev)
 260 {
 261         const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 262
 263         return sdrv->probe(to_serdev_device(dev));
 264 }
 265
 266 static int serdev_drv_remove(struct device *dev)
 267 {
 268         const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 269
 270         sdrv->remove(to_serdev_device(dev));
 271         return 0;
 272 }
 273
 274 static ssize_t modalias_show(struct device *dev,
 275                              struct device_attribute *attr, char *buf)
 276 {
 277         return of_device_modalias(dev, buf, PAGE_SIZE);
 278 }
 279 DEVICE_ATTR_RO(modalias);
 280
 281 static struct attribute *serdev_device_attrs[] = {
 282         &dev_attr_modalias.attr,
 283         NULL,
 284 };
 285 ATTRIBUTE_GROUPS(serdev_device);
 286
 287 static struct bus_type serdev_bus_type = {
 288         .name           = "serial",
 289         .match          = serdev_device_match,
 290         .probe          = serdev_drv_probe,
 291         .remove         = serdev_drv_remove,
 292         .uevent         = serdev_uevent,
 293         .dev_groups     = serdev_device_groups,
 294 };
 295
 296 /**
 297  * serdev_controller_alloc() - Allocate a new serdev device
 298  * @ctrl:       associated controller
 299  *
 300  * Caller is responsible for either calling serdev_device_add() to add the
 301  * newly allocated controller, or calling serdev_device_put() to discard it.
 302  */
 303 struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
 304 {
 305         struct serdev_device *serdev;
 306
 307         serdev = kzalloc(sizeof(*serdev), GFP_KERNEL);
 308         if (!serdev)
 309                 return NULL;
 310
 311         serdev->ctrl = ctrl;
 312         device_initialize(&serdev->dev);
 313         serdev->dev.parent = &ctrl->dev;
 314         serdev->dev.bus = &serdev_bus_type;
 315         serdev->dev.type = &serdev_device_type;
 316         init_completion(&serdev->write_comp);
 317         mutex_init(&serdev->write_lock);
 318         return serdev;
 319 }
 320 EXPORT_SYMBOL_GPL(serdev_device_alloc);
 321
 322 /**
 323  * serdev_controller_alloc() - Allocate a new serdev controller
 324  * @parent:     parent device
 325  * @size:       size of private data
 326  *
 327  * Caller is responsible for either calling serdev_controller_add() to add the
 328  * newly allocated controller, or calling serdev_controller_put() to discard it.
 329  * The allocated private data region may be accessed via
 330  * serdev_controller_get_drvdata()
 331  */
 332 struct serdev_controller *serdev_controller_alloc(struct device *parent,
 333                                               size_t size)
 334 {
 335         struct serdev_controller *ctrl;
 336         int id;
 337
 338         if (WARN_ON(!parent))
 339                 return NULL;
 340
 341         ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
 342         if (!ctrl)
 343                 return NULL;
 344
 345         device_initialize(&ctrl->dev);
 346         ctrl->dev.type = &serdev_ctrl_type;
 347         ctrl->dev.bus = &serdev_bus_type;
 348         ctrl->dev.parent = parent;
 349         ctrl->dev.of_node = parent->of_node;
 350         serdev_controller_set_drvdata(ctrl, &ctrl[1]);
 351
 352         id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
 353         if (id < 0) {
 354                 dev_err(parent,
 355                         "unable to allocate serdev controller identifier.\n");
 356                 serdev_controller_put(ctrl);
 357                 return NULL;
 358         }
 359
 360         ctrl->nr = id;
 361         dev_set_name(&ctrl->dev, "serial%d", id);
 362
 363         dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
 364         return ctrl;
 365 }
 366 EXPORT_SYMBOL_GPL(serdev_controller_alloc);
 367
 368 static int of_serdev_register_devices(struct serdev_controller *ctrl)
 369 {
 370         struct device_node *node;
 371         struct serdev_device *serdev = NULL;
 372         int err;
 373         bool found = false;
 374
 375         for_each_available_child_of_node(ctrl->dev.of_node, node) {
 376                 if (!of_get_property(node, "compatible", NULL))
 377                         continue;
 378
 379                 dev_dbg(&ctrl->dev, "adding child %pOF\n", node);
 380
 381                 serdev = serdev_device_alloc(ctrl);
 382                 if (!serdev)
 383                         continue;
 384
 385                 serdev->dev.of_node = node;
 386
 387                 err = serdev_device_add(serdev);
 388                 if (err) {
 389                         dev_err(&serdev->dev,
 390                                 "failure adding device. status %d\n", err);
 391                         serdev_device_put(serdev);
 392                 } else
 393                         found = true;
 394         }
 395         if (!found)
 396                 return -ENODEV;
 397
 398         return 0;
 399 }
 400
 401 /**
 402  * serdev_controller_add() - Add an serdev controller
 403  * @ctrl:       controller to be registered.
 404  *
 405  * Register a controller previously allocated via serdev_controller_alloc() with
 406  * the serdev core.
 407  */
 408 int serdev_controller_add(struct serdev_controller *ctrl)
 409 {
 410         int ret;
 411
 412         /* Can't register until after driver model init */
 413         if (WARN_ON(!is_registered))
 414                 return -EAGAIN;
 415
 416         ret = device_add(&ctrl->dev);
 417         if (ret)
 418                 return ret;
 419
 420         ret = of_serdev_register_devices(ctrl);
 421         if (ret)
 422                 goto out_dev_del;
 423
 424         dev_dbg(&ctrl->dev, "serdev%d registered: dev:%p\n",
 425                 ctrl->nr, &ctrl->dev);
 426         return 0;
 427
 428 out_dev_del:
 429         device_del(&ctrl->dev);
 430         return ret;
 431 };
 432 EXPORT_SYMBOL_GPL(serdev_controller_add);
 433
 434 /* Remove a device associated with a controller */
 435 static int serdev_remove_device(struct device *dev, void *data)
 436 {
 437         struct serdev_device *serdev = to_serdev_device(dev);
 438         if (dev->type == &serdev_device_type)
 439                 serdev_device_remove(serdev);
 440         return 0;
 441 }
 442
 443 /**
 444  * serdev_controller_remove(): remove an serdev controller
 445  * @ctrl:       controller to remove
 446  *
 447  * Remove a serdev controller.  Caller is responsible for calling
 448  * serdev_controller_put() to discard the allocated controller.
 449  */
 450 void serdev_controller_remove(struct serdev_controller *ctrl)
 451 {
 452         int dummy;
 453
 454         if (!ctrl)
 455                 return;
 456
 457         dummy = device_for_each_child(&ctrl->dev, NULL,
 458                                       serdev_remove_device);
 459         device_del(&ctrl->dev);
 460 }
 461 EXPORT_SYMBOL_GPL(serdev_controller_remove);
 462
 463 /**
 464  * serdev_driver_register() - Register client driver with serdev core
 465  * @sdrv:       client driver to be associated with client-device.
 466  *
 467  * This API will register the client driver with the serdev framework.
 468  * It is typically called from the driver's module-init function.
 469  */
 470 int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct module *owner)
 471 {
 472         sdrv->driver.bus = &serdev_bus_type;
 473         sdrv->driver.owner = owner;
 474
 475         /* force drivers to async probe so I/O is possible in probe */
 476         sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
 477
 478         return driver_register(&sdrv->driver);
 479 }
 480 EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
 481
 482 static void __exit serdev_exit(void)
 483 {
 484         bus_unregister(&serdev_bus_type);
 485         ida_destroy(&ctrl_ida);
 486 }
 487 module_exit(serdev_exit);
 488
 489 static int __init serdev_init(void)
 490 {
 491         int ret;
 492
 493         ret = bus_register(&serdev_bus_type);
 494         if (ret)
 495                 return ret;
 496
 497         is_registered = true;
 498         return 0;
 499 }
 500 /* Must be before serial drivers register */
 501 postcore_initcall(serdev_init);
 502
 503 MODULE_AUTHOR("Rob Herring <robh@kernel.org>");
 504 MODULE_LICENSE("GPL v2");
 505 MODULE_DESCRIPTION("Serial attached device bus");