drivers/mcb/mcb-core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * MEN Chameleon Bus.
   4  *
   5  * Copyright (C) 2013 MEN Mikroelektronik GmbH (www.men.de)
   6  * Author: Johannes Thumshirn <johannes.thumshirn@men.de>
   7  */
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/slab.h>
  11 #include <linux/types.h>
  12 #include <linux/idr.h>
  13 #include <linux/mcb.h>
  14
  15 static DEFINE_IDA(mcb_ida);
  16
  17 static const struct mcb_device_id *mcb_match_id(const struct mcb_device_id *ids,
  18                                                 struct mcb_device *dev)
  19 {
  20         if (ids) {
  21                 while (ids->device) {
  22                         if (ids->device == dev->id)
  23                                 return ids;
  24                         ids++;
  25                 }
  26         }
  27
  28         return NULL;
  29 }
  30
  31 static int mcb_match(struct device *dev, struct device_driver *drv)
  32 {
  33         struct mcb_driver *mdrv = to_mcb_driver(drv);
  34         struct mcb_device *mdev = to_mcb_device(dev);
  35         const struct mcb_device_id *found_id;
  36
  37         found_id = mcb_match_id(mdrv->id_table, mdev);
  38         if (found_id)
  39                 return 1;
  40
  41         return 0;
  42 }
  43
  44 static int mcb_uevent(struct device *dev, struct kobj_uevent_env *env)
  45 {
  46         struct mcb_device *mdev = to_mcb_device(dev);
  47         int ret;
  48
  49         ret = add_uevent_var(env, "MODALIAS=mcb:16z%03d", mdev->id);
  50         if (ret)
  51                 return -ENOMEM;
  52
  53         return 0;
  54 }
  55
  56 static int mcb_probe(struct device *dev)
  57 {
  58         struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
  59         struct mcb_device *mdev = to_mcb_device(dev);
  60         const struct mcb_device_id *found_id;
  61         struct module *carrier_mod;
  62         int ret;
  63
  64         found_id = mcb_match_id(mdrv->id_table, mdev);
  65         if (!found_id)
  66                 return -ENODEV;
  67
  68         carrier_mod = mdev->dev.parent->driver->owner;
  69         if (!try_module_get(carrier_mod))
  70                 return -EINVAL;
  71
  72         get_device(dev);
  73         ret = mdrv->probe(mdev, found_id);
  74         if (ret)
  75                 module_put(carrier_mod);
  76
  77         return ret;
  78 }
  79
  80 static int mcb_remove(struct device *dev)
  81 {
  82         struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
  83         struct mcb_device *mdev = to_mcb_device(dev);
  84         struct module *carrier_mod;
  85
  86         mdrv->remove(mdev);
  87
  88         carrier_mod = mdev->dev.parent->driver->owner;
  89         module_put(carrier_mod);
  90
  91         put_device(&mdev->dev);
  92
  93         return 0;
  94 }
  95
  96 static void mcb_shutdown(struct device *dev)
  97 {
  98         struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
  99         struct mcb_device *mdev = to_mcb_device(dev);
 100
 101         if (mdrv && mdrv->shutdown)
 102                 mdrv->shutdown(mdev);
 103 }
 104
 105 static ssize_t revision_show(struct device *dev, struct device_attribute *attr,
 106                          char *buf)
 107 {
 108         struct mcb_bus *bus = to_mcb_bus(dev);
 109
 110         return scnprintf(buf, PAGE_SIZE, "%d\n", bus->revision);
 111 }
 112 static DEVICE_ATTR_RO(revision);
 113
 114 static ssize_t model_show(struct device *dev, struct device_attribute *attr,
 115                          char *buf)
 116 {
 117         struct mcb_bus *bus = to_mcb_bus(dev);
 118
 119         return scnprintf(buf, PAGE_SIZE, "%c\n", bus->model);
 120 }
 121 static DEVICE_ATTR_RO(model);
 122
 123 static ssize_t minor_show(struct device *dev, struct device_attribute *attr,
 124                          char *buf)
 125 {
 126         struct mcb_bus *bus = to_mcb_bus(dev);
 127
 128         return scnprintf(buf, PAGE_SIZE, "%d\n", bus->minor);
 129 }
 130 static DEVICE_ATTR_RO(minor);
 131
 132 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
 133                          char *buf)
 134 {
 135         struct mcb_bus *bus = to_mcb_bus(dev);
 136
 137         return scnprintf(buf, PAGE_SIZE, "%s\n", bus->name);
 138 }
 139 static DEVICE_ATTR_RO(name);
 140
 141 static struct attribute *mcb_bus_attrs[] = {
 142         &dev_attr_revision.attr,
 143         &dev_attr_model.attr,
 144         &dev_attr_minor.attr,
 145         &dev_attr_name.attr,
 146         NULL,
 147 };
 148
 149 static const struct attribute_group mcb_carrier_group = {
 150         .attrs = mcb_bus_attrs,
 151 };
 152
 153 static const struct attribute_group *mcb_carrier_groups[] = {
 154         &mcb_carrier_group,
 155         NULL,
 156 };
 157
 158
 159 static struct bus_type mcb_bus_type = {
 160         .name = "mcb",
 161         .match = mcb_match,
 162         .uevent = mcb_uevent,
 163         .probe = mcb_probe,
 164         .remove = mcb_remove,
 165         .shutdown = mcb_shutdown,
 166 };
 167
 168 static struct device_type mcb_carrier_device_type = {
 169         .name = "mcb-carrier",
 170         .groups = mcb_carrier_groups,
 171 };
 172
 173 /**
 174  * __mcb_register_driver() - Register a @mcb_driver at the system
 175  * @drv: The @mcb_driver
 176  * @owner: The @mcb_driver's module
 177  * @mod_name: The name of the @mcb_driver's module
 178  *
 179  * Register a @mcb_driver at the system. Perform some sanity checks, if
 180  * the .probe and .remove methods are provided by the driver.
 181  */
 182 int __mcb_register_driver(struct mcb_driver *drv, struct module *owner,
 183                         const char *mod_name)
 184 {
 185         if (!drv->probe || !drv->remove)
 186                 return -EINVAL;
 187
 188         drv->driver.owner = owner;
 189         drv->driver.bus = &mcb_bus_type;
 190         drv->driver.mod_name = mod_name;
 191
 192         return driver_register(&drv->driver);
 193 }
 194 EXPORT_SYMBOL_GPL(__mcb_register_driver);
 195
 196 /**
 197  * mcb_unregister_driver() - Unregister a @mcb_driver from the system
 198  * @drv: The @mcb_driver
 199  *
 200  * Unregister a @mcb_driver from the system.
 201  */
 202 void mcb_unregister_driver(struct mcb_driver *drv)
 203 {
 204         driver_unregister(&drv->driver);
 205 }
 206 EXPORT_SYMBOL_GPL(mcb_unregister_driver);
 207
 208 static void mcb_release_dev(struct device *dev)
 209 {
 210         struct mcb_device *mdev = to_mcb_device(dev);
 211
 212         mcb_bus_put(mdev->bus);
 213         kfree(mdev);
 214 }
 215
 216 /**
 217  * mcb_device_register() - Register a mcb_device
 218  * @bus: The @mcb_bus of the device
 219  * @dev: The @mcb_device
 220  *
 221  * Register a specific @mcb_device at a @mcb_bus and the system itself.
 222  */
 223 int mcb_device_register(struct mcb_bus *bus, struct mcb_device *dev)
 224 {
 225         int ret;
 226         int device_id;
 227
 228         device_initialize(&dev->dev);
 229         mcb_bus_get(bus);
 230         dev->dev.bus = &mcb_bus_type;
 231         dev->dev.parent = bus->dev.parent;
 232         dev->dev.release = mcb_release_dev;
 233         dev->dma_dev = bus->carrier;
 234
 235         device_id = dev->id;
 236         dev_set_name(&dev->dev, "mcb%d-16z%03d-%d:%d:%d",
 237                 bus->bus_nr, device_id, dev->inst, dev->group, dev->var);
 238
 239         ret = device_add(&dev->dev);
 240         if (ret < 0) {
 241                 pr_err("Failed registering device 16z%03d on bus mcb%d (%d)\n",
 242                         device_id, bus->bus_nr, ret);
 243                 goto out;
 244         }
 245
 246         return 0;
 247
 248 out:
 249
 250         return ret;
 251 }
 252 EXPORT_SYMBOL_GPL(mcb_device_register);
 253
 254 static void mcb_free_bus(struct device *dev)
 255 {
 256         struct mcb_bus *bus = to_mcb_bus(dev);
 257
 258         put_device(bus->carrier);
 259         ida_simple_remove(&mcb_ida, bus->bus_nr);
 260         kfree(bus);
 261 }
 262
 263 /**
 264  * mcb_alloc_bus() - Allocate a new @mcb_bus
 265  *
 266  * Allocate a new @mcb_bus.
 267  */
 268 struct mcb_bus *mcb_alloc_bus(struct device *carrier)
 269 {
 270         struct mcb_bus *bus;
 271         int bus_nr;
 272         int rc;
 273
 274         bus = kzalloc(sizeof(struct mcb_bus), GFP_KERNEL);
 275         if (!bus)
 276                 return ERR_PTR(-ENOMEM);
 277
 278         bus_nr = ida_simple_get(&mcb_ida, 0, 0, GFP_KERNEL);
 279         if (bus_nr < 0) {
 280                 rc = bus_nr;
 281                 goto err_free;
 282         }
 283
 284         bus->bus_nr = bus_nr;
 285         bus->carrier = get_device(carrier);
 286
 287         device_initialize(&bus->dev);
 288         bus->dev.parent = carrier;
 289         bus->dev.bus = &mcb_bus_type;
 290         bus->dev.type = &mcb_carrier_device_type;
 291         bus->dev.release = &mcb_free_bus;
 292
 293         dev_set_name(&bus->dev, "mcb:%d", bus_nr);
 294         rc = device_add(&bus->dev);
 295         if (rc)
 296                 goto err_free;
 297
 298         return bus;
 299 err_free:
 300         put_device(carrier);
 301         kfree(bus);
 302         return ERR_PTR(rc);
 303 }
 304 EXPORT_SYMBOL_GPL(mcb_alloc_bus);
 305
 306 static int __mcb_devices_unregister(struct device *dev, void *data)
 307 {
 308         device_unregister(dev);
 309         return 0;
 310 }
 311
 312 static void mcb_devices_unregister(struct mcb_bus *bus)
 313 {
 314         bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_devices_unregister);
 315 }
 316 /**
 317  * mcb_release_bus() - Free a @mcb_bus
 318  * @bus: The @mcb_bus to release
 319  *
 320  * Release an allocated @mcb_bus from the system.
 321  */
 322 void mcb_release_bus(struct mcb_bus *bus)
 323 {
 324         mcb_devices_unregister(bus);
 325 }
 326 EXPORT_SYMBOL_GPL(mcb_release_bus);
 327
 328 /**
 329  * mcb_bus_put() - Increment refcnt
 330  * @bus: The @mcb_bus
 331  *
 332  * Get a @mcb_bus' ref
 333  */
 334 struct mcb_bus *mcb_bus_get(struct mcb_bus *bus)
 335 {
 336         if (bus)
 337                 get_device(&bus->dev);
 338
 339         return bus;
 340 }
 341 EXPORT_SYMBOL_GPL(mcb_bus_get);
 342
 343 /**
 344  * mcb_bus_put() - Decrement refcnt
 345  * @bus: The @mcb_bus
 346  *
 347  * Release a @mcb_bus' ref
 348  */
 349 void mcb_bus_put(struct mcb_bus *bus)
 350 {
 351         if (bus)
 352                 put_device(&bus->dev);
 353 }
 354 EXPORT_SYMBOL_GPL(mcb_bus_put);
 355
 356 /**
 357  * mcb_alloc_dev() - Allocate a device
 358  * @bus: The @mcb_bus the device is part of
 359  *
 360  * Allocate a @mcb_device and add bus.
 361  */
 362 struct mcb_device *mcb_alloc_dev(struct mcb_bus *bus)
 363 {
 364         struct mcb_device *dev;
 365
 366         dev = kzalloc(sizeof(struct mcb_device), GFP_KERNEL);
 367         if (!dev)
 368                 return NULL;
 369
 370         dev->bus = bus;
 371
 372         return dev;
 373 }
 374 EXPORT_SYMBOL_GPL(mcb_alloc_dev);
 375
 376 /**
 377  * mcb_free_dev() - Free @mcb_device
 378  * @dev: The device to free
 379  *
 380  * Free a @mcb_device
 381  */
 382 void mcb_free_dev(struct mcb_device *dev)
 383 {
 384         kfree(dev);
 385 }
 386 EXPORT_SYMBOL_GPL(mcb_free_dev);
 387
 388 static int __mcb_bus_add_devices(struct device *dev, void *data)
 389 {
 390         struct mcb_device *mdev = to_mcb_device(dev);
 391         int retval;
 392
 393         if (mdev->is_added)
 394                 return 0;
 395
 396         retval = device_attach(dev);
 397         if (retval < 0)
 398                 dev_err(dev, "Error adding device (%d)\n", retval);
 399
 400         mdev->is_added = true;
 401
 402         return 0;
 403 }
 404
 405 /**
 406  * mcb_bus_add_devices() - Add devices in the bus' internal device list
 407  * @bus: The @mcb_bus we add the devices
 408  *
 409  * Add devices in the bus' internal device list to the system.
 410  */
 411 void mcb_bus_add_devices(const struct mcb_bus *bus)
 412 {
 413         bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_bus_add_devices);
 414 }
 415 EXPORT_SYMBOL_GPL(mcb_bus_add_devices);
 416
 417 /**
 418  * mcb_get_resource() - get a resource for a mcb device
 419  * @dev: the mcb device
 420  * @type: the type of resource
 421  */
 422 struct resource *mcb_get_resource(struct mcb_device *dev, unsigned int type)
 423 {
 424         if (type == IORESOURCE_MEM)
 425                 return &dev->mem;
 426         else if (type == IORESOURCE_IRQ)
 427                 return &dev->irq;
 428         else
 429                 return NULL;
 430 }
 431 EXPORT_SYMBOL_GPL(mcb_get_resource);
 432
 433 /**
 434  * mcb_request_mem() - Request memory
 435  * @dev: The @mcb_device the memory is for
 436  * @name: The name for the memory reference.
 437  *
 438  * Request memory for a @mcb_device. If @name is NULL the driver name will
 439  * be used.
 440  */
 441 struct resource *mcb_request_mem(struct mcb_device *dev, const char *name)
 442 {
 443         struct resource *mem;
 444         u32 size;
 445
 446         if (!name)
 447                 name = dev->dev.driver->name;
 448
 449         size = resource_size(&dev->mem);
 450
 451         mem = request_mem_region(dev->mem.start, size, name);
 452         if (!mem)
 453                 return ERR_PTR(-EBUSY);
 454
 455         return mem;
 456 }
 457 EXPORT_SYMBOL_GPL(mcb_request_mem);
 458
 459 /**
 460  * mcb_release_mem() - Release memory requested by device
 461  * @dev: The @mcb_device that requested the memory
 462  *
 463  * Release memory that was prior requested via @mcb_request_mem().
 464  */
 465 void mcb_release_mem(struct resource *mem)
 466 {
 467         u32 size;
 468
 469         size = resource_size(mem);
 470         release_mem_region(mem->start, size);
 471 }
 472 EXPORT_SYMBOL_GPL(mcb_release_mem);
 473
 474 static int __mcb_get_irq(struct mcb_device *dev)
 475 {
 476         struct resource *irq;
 477
 478         irq = mcb_get_resource(dev, IORESOURCE_IRQ);
 479
 480         return irq->start;
 481 }
 482
 483 /**
 484  * mcb_get_irq() - Get device's IRQ number
 485  * @dev: The @mcb_device the IRQ is for
 486  *
 487  * Get the IRQ number of a given @mcb_device.
 488  */
 489 int mcb_get_irq(struct mcb_device *dev)
 490 {
 491         struct mcb_bus *bus = dev->bus;
 492
 493         if (bus->get_irq)
 494                 return bus->get_irq(dev);
 495
 496         return __mcb_get_irq(dev);
 497 }
 498 EXPORT_SYMBOL_GPL(mcb_get_irq);
 499
 500 static int mcb_init(void)
 501 {
 502         return bus_register(&mcb_bus_type);
 503 }
 504
 505 static void mcb_exit(void)
 506 {
 507         ida_destroy(&mcb_ida);
 508         bus_unregister(&mcb_bus_type);
 509 }
 510
 511 /* mcb must be initialized after PCI but before the chameleon drivers.
 512  * That means we must use some initcall between subsys_initcall and
 513  * device_initcall.
 514  */
 515 fs_initcall(mcb_init);
 516 module_exit(mcb_exit);
 517
 518 MODULE_DESCRIPTION("MEN Chameleon Bus Driver");
 519 MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
 520 MODULE_LICENSE("GPL v2");