drivers/mcb/mcb-core.c

   1 /*
   2  * MEN Chameleon Bus.
   3  *
   4  * Copyright (C) 2013 MEN Mikroelektronik GmbH (www.men.de)
   5  * Author: Johannes Thumshirn <johannes.thumshirn@men.de>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the Free
   9  * Software Foundation; version 2 of the License.
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/types.h>
  15 #include <linux/idr.h>
  16 #include <linux/mcb.h>
  17
  18 static DEFINE_IDA(mcb_ida);
  19
  20 static const struct mcb_device_id *mcb_match_id(const struct mcb_device_id *ids,
  21                                                 struct mcb_device *dev)
  22 {
  23         if (ids) {
  24                 while (ids->device) {
  25                         if (ids->device == dev->id)
  26                                 return ids;
  27                         ids++;
  28                 }
  29         }
  30
  31         return NULL;
  32 }
  33
  34 static int mcb_match(struct device *dev, struct device_driver *drv)
  35 {
  36         struct mcb_driver *mdrv = to_mcb_driver(drv);
  37         struct mcb_device *mdev = to_mcb_device(dev);
  38         const struct mcb_device_id *found_id;
  39
  40         found_id = mcb_match_id(mdrv->id_table, mdev);
  41         if (found_id)
  42                 return 1;
  43
  44         return 0;
  45 }
  46
  47 static int mcb_uevent(struct device *dev, struct kobj_uevent_env *env)
  48 {
  49         struct mcb_device *mdev = to_mcb_device(dev);
  50         int ret;
  51
  52         ret = add_uevent_var(env, "MODALIAS=mcb:16z%03d", mdev->id);
  53         if (ret)
  54                 return -ENOMEM;
  55
  56         return 0;
  57 }
  58
  59 static int mcb_probe(struct device *dev)
  60 {
  61         struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
  62         struct mcb_device *mdev = to_mcb_device(dev);
  63         const struct mcb_device_id *found_id;
  64
  65         found_id = mcb_match_id(mdrv->id_table, mdev);
  66         if (!found_id)
  67                 return -ENODEV;
  68
  69         return mdrv->probe(mdev, found_id);
  70 }
  71
  72 static int mcb_remove(struct device *dev)
  73 {
  74         struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
  75         struct mcb_device *mdev = to_mcb_device(dev);
  76
  77         mdrv->remove(mdev);
  78
  79         put_device(&mdev->dev);
  80
  81         return 0;
  82 }
  83
  84 static void mcb_shutdown(struct device *dev)
  85 {
  86         struct mcb_device *mdev = to_mcb_device(dev);
  87         struct mcb_driver *mdrv = mdev->driver;
  88
  89         if (mdrv && mdrv->shutdown)
  90                 mdrv->shutdown(mdev);
  91 }
  92
  93 static struct bus_type mcb_bus_type = {
  94         .name = "mcb",
  95         .match = mcb_match,
  96         .uevent = mcb_uevent,
  97         .probe = mcb_probe,
  98         .remove = mcb_remove,
  99         .shutdown = mcb_shutdown,
 100 };
 101
 102 /**
 103  * __mcb_register_driver() - Register a @mcb_driver at the system
 104  * @drv: The @mcb_driver
 105  * @owner: The @mcb_driver's module
 106  * @mod_name: The name of the @mcb_driver's module
 107  *
 108  * Register a @mcb_driver at the system. Perform some sanity checks, if
 109  * the .probe and .remove methods are provided by the driver.
 110  */
 111 int __mcb_register_driver(struct mcb_driver *drv, struct module *owner,
 112                         const char *mod_name)
 113 {
 114         if (!drv->probe || !drv->remove)
 115                 return -EINVAL;
 116
 117         drv->driver.owner = owner;
 118         drv->driver.bus = &mcb_bus_type;
 119         drv->driver.mod_name = mod_name;
 120
 121         return driver_register(&drv->driver);
 122 }
 123 EXPORT_SYMBOL_GPL(__mcb_register_driver);
 124
 125 /**
 126  * mcb_unregister_driver() - Unregister a @mcb_driver from the system
 127  * @drv: The @mcb_driver
 128  *
 129  * Unregister a @mcb_driver from the system.
 130  */
 131 void mcb_unregister_driver(struct mcb_driver *drv)
 132 {
 133         driver_unregister(&drv->driver);
 134 }
 135 EXPORT_SYMBOL_GPL(mcb_unregister_driver);
 136
 137 static void mcb_release_dev(struct device *dev)
 138 {
 139         struct mcb_device *mdev = to_mcb_device(dev);
 140
 141         mcb_bus_put(mdev->bus);
 142         kfree(mdev);
 143 }
 144
 145 /**
 146  * mcb_device_register() - Register a mcb_device
 147  * @bus: The @mcb_bus of the device
 148  * @dev: The @mcb_device
 149  *
 150  * Register a specific @mcb_device at a @mcb_bus and the system itself.
 151  */
 152 int mcb_device_register(struct mcb_bus *bus, struct mcb_device *dev)
 153 {
 154         int ret;
 155         int device_id;
 156
 157         device_initialize(&dev->dev);
 158         dev->dev.bus = &mcb_bus_type;
 159         dev->dev.parent = bus->dev.parent;
 160         dev->dev.release = mcb_release_dev;
 161
 162         device_id = dev->id;
 163         dev_set_name(&dev->dev, "mcb%d-16z%03d-%d:%d:%d",
 164                 bus->bus_nr, device_id, dev->inst, dev->group, dev->var);
 165
 166         ret = device_add(&dev->dev);
 167         if (ret < 0) {
 168                 pr_err("Failed registering device 16z%03d on bus mcb%d (%d)\n",
 169                         device_id, bus->bus_nr, ret);
 170                 goto out;
 171         }
 172
 173         return 0;
 174
 175 out:
 176
 177         return ret;
 178 }
 179 EXPORT_SYMBOL_GPL(mcb_device_register);
 180
 181 /**
 182  * mcb_alloc_bus() - Allocate a new @mcb_bus
 183  *
 184  * Allocate a new @mcb_bus.
 185  */
 186 struct mcb_bus *mcb_alloc_bus(struct device *carrier)
 187 {
 188         struct mcb_bus *bus;
 189         int bus_nr;
 190
 191         bus = kzalloc(sizeof(struct mcb_bus), GFP_KERNEL);
 192         if (!bus)
 193                 return ERR_PTR(-ENOMEM);
 194
 195         bus_nr = ida_simple_get(&mcb_ida, 0, 0, GFP_KERNEL);
 196         if (bus_nr < 0) {
 197                 kfree(bus);
 198                 return ERR_PTR(bus_nr);
 199         }
 200
 201         INIT_LIST_HEAD(&bus->children);
 202         bus->bus_nr = bus_nr;
 203         bus->carrier = carrier;
 204         return bus;
 205 }
 206 EXPORT_SYMBOL_GPL(mcb_alloc_bus);
 207
 208 static int __mcb_devices_unregister(struct device *dev, void *data)
 209 {
 210         device_unregister(dev);
 211         return 0;
 212 }
 213
 214 static void mcb_devices_unregister(struct mcb_bus *bus)
 215 {
 216         bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_devices_unregister);
 217 }
 218 /**
 219  * mcb_release_bus() - Free a @mcb_bus
 220  * @bus: The @mcb_bus to release
 221  *
 222  * Release an allocated @mcb_bus from the system.
 223  */
 224 void mcb_release_bus(struct mcb_bus *bus)
 225 {
 226         mcb_devices_unregister(bus);
 227
 228         ida_simple_remove(&mcb_ida, bus->bus_nr);
 229
 230         kfree(bus);
 231 }
 232 EXPORT_SYMBOL_GPL(mcb_release_bus);
 233
 234 /**
 235  * mcb_bus_put() - Increment refcnt
 236  * @bus: The @mcb_bus
 237  *
 238  * Get a @mcb_bus' ref
 239  */
 240 struct mcb_bus *mcb_bus_get(struct mcb_bus *bus)
 241 {
 242         if (bus)
 243                 get_device(&bus->dev);
 244
 245         return bus;
 246 }
 247 EXPORT_SYMBOL_GPL(mcb_bus_get);
 248
 249 /**
 250  * mcb_bus_put() - Decrement refcnt
 251  * @bus: The @mcb_bus
 252  *
 253  * Release a @mcb_bus' ref
 254  */
 255 void mcb_bus_put(struct mcb_bus *bus)
 256 {
 257         if (bus)
 258                 put_device(&bus->dev);
 259 }
 260 EXPORT_SYMBOL_GPL(mcb_bus_put);
 261
 262 /**
 263  * mcb_alloc_dev() - Allocate a device
 264  * @bus: The @mcb_bus the device is part of
 265  *
 266  * Allocate a @mcb_device and add bus.
 267  */
 268 struct mcb_device *mcb_alloc_dev(struct mcb_bus *bus)
 269 {
 270         struct mcb_device *dev;
 271
 272         dev = kzalloc(sizeof(struct mcb_device), GFP_KERNEL);
 273         if (!dev)
 274                 return NULL;
 275
 276         INIT_LIST_HEAD(&dev->bus_list);
 277         dev->bus = bus;
 278
 279         return dev;
 280 }
 281 EXPORT_SYMBOL_GPL(mcb_alloc_dev);
 282
 283 /**
 284  * mcb_free_dev() - Free @mcb_device
 285  * @dev: The device to free
 286  *
 287  * Free a @mcb_device
 288  */
 289 void mcb_free_dev(struct mcb_device *dev)
 290 {
 291         kfree(dev);
 292 }
 293 EXPORT_SYMBOL_GPL(mcb_free_dev);
 294
 295 static int __mcb_bus_add_devices(struct device *dev, void *data)
 296 {
 297         struct mcb_device *mdev = to_mcb_device(dev);
 298         int retval;
 299
 300         if (mdev->is_added)
 301                 return 0;
 302
 303         retval = device_attach(dev);
 304         if (retval < 0)
 305                 dev_err(dev, "Error adding device (%d)\n", retval);
 306
 307         mdev->is_added = true;
 308
 309         return 0;
 310 }
 311
 312 static int __mcb_bus_add_child(struct device *dev, void *data)
 313 {
 314         struct mcb_device *mdev = to_mcb_device(dev);
 315         struct mcb_bus *child;
 316
 317         BUG_ON(!mdev->is_added);
 318         child = mdev->subordinate;
 319
 320         if (child)
 321                 mcb_bus_add_devices(child);
 322
 323         return 0;
 324 }
 325
 326 /**
 327  * mcb_bus_add_devices() - Add devices in the bus' internal device list
 328  * @bus: The @mcb_bus we add the devices
 329  *
 330  * Add devices in the bus' internal device list to the system.
 331  */
 332 void mcb_bus_add_devices(const struct mcb_bus *bus)
 333 {
 334         bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_bus_add_devices);
 335         bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_bus_add_child);
 336
 337 }
 338 EXPORT_SYMBOL_GPL(mcb_bus_add_devices);
 339
 340 /**
 341  * mcb_request_mem() - Request memory
 342  * @dev: The @mcb_device the memory is for
 343  * @name: The name for the memory reference.
 344  *
 345  * Request memory for a @mcb_device. If @name is NULL the driver name will
 346  * be used.
 347  */
 348 struct resource *mcb_request_mem(struct mcb_device *dev, const char *name)
 349 {
 350         struct resource *mem;
 351         u32 size;
 352
 353         if (!name)
 354                 name = dev->dev.driver->name;
 355
 356         size = resource_size(&dev->mem);
 357
 358         mem = request_mem_region(dev->mem.start, size, name);
 359         if (!mem)
 360                 return ERR_PTR(-EBUSY);
 361
 362         return mem;
 363 }
 364 EXPORT_SYMBOL_GPL(mcb_request_mem);
 365
 366 /**
 367  * mcb_release_mem() - Release memory requested by device
 368  * @dev: The @mcb_device that requested the memory
 369  *
 370  * Release memory that was prior requested via @mcb_request_mem().
 371  */
 372 void mcb_release_mem(struct resource *mem)
 373 {
 374         u32 size;
 375
 376         size = resource_size(mem);
 377         release_mem_region(mem->start, size);
 378 }
 379 EXPORT_SYMBOL_GPL(mcb_release_mem);
 380
 381 static int __mcb_get_irq(struct mcb_device *dev)
 382 {
 383         struct resource *irq = &dev->irq;
 384
 385         return irq->start;
 386 }
 387
 388 /**
 389  * mcb_get_irq() - Get device's IRQ number
 390  * @dev: The @mcb_device the IRQ is for
 391  *
 392  * Get the IRQ number of a given @mcb_device.
 393  */
 394 int mcb_get_irq(struct mcb_device *dev)
 395 {
 396         struct mcb_bus *bus = dev->bus;
 397
 398         if (bus->get_irq)
 399                 return bus->get_irq(dev);
 400
 401         return __mcb_get_irq(dev);
 402 }
 403 EXPORT_SYMBOL_GPL(mcb_get_irq);
 404
 405 static int mcb_init(void)
 406 {
 407         return bus_register(&mcb_bus_type);
 408 }
 409
 410 static void mcb_exit(void)
 411 {
 412         bus_unregister(&mcb_bus_type);
 413 }
 414
 415 /* mcb must be initialized after PCI but before the chameleon drivers.
 416  * That means we must use some initcall between subsys_initcall and
 417  * device_initcall.
 418  */
 419 fs_initcall(mcb_init);
 420 module_exit(mcb_exit);
 421
 422 MODULE_DESCRIPTION("MEN Chameleon Bus Driver");
 423 MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
 424 MODULE_LICENSE("GPL v2");