wimax.h revision c2315b4ea9ac9c3f8caf03c3511d86fabe4a5fcd
1/* 2 * Linux WiMAX 3 * Kernel space API for accessing WiMAX devices 4 * 5 * 6 * Copyright (C) 2007-2008 Intel Corporation <linux-wimax@intel.com> 7 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com> 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License version 11 * 2 as published by the Free Software Foundation. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 21 * 02110-1301, USA. 22 * 23 * 24 * The WiMAX stack provides an API for controlling and managing the 25 * system's WiMAX devices. This API affects the control plane; the 26 * data plane is accessed via the network stack (netdev). 27 * 28 * Parts of the WiMAX stack API and notifications are exported to 29 * user space via Generic Netlink. In user space, libwimax (part of 30 * the wimax-tools package) provides a shim layer for accessing those 31 * calls. 32 * 33 * The API is standarized for all WiMAX devices and different drivers 34 * implement the backend support for it. However, device-specific 35 * messaging pipes are provided that can be used to issue commands and 36 * receive notifications in free form. 37 * 38 * Currently the messaging pipes are the only means of control as it 39 * is not known (due to the lack of more devices in the market) what 40 * will be a good abstraction layer. Expect this to change as more 41 * devices show in the market. This API is designed to be growable in 42 * order to address this problem. 43 * 44 * USAGE 45 * 46 * Embed a `struct wimax_dev` at the beginning of the the device's 47 * private structure, initialize and register it. For details, see 48 * `struct wimax_dev`s documentation. 49 * 50 * Once this is done, wimax-tools's libwimaxll can be used to 51 * communicate with the driver from user space. You user space 52 * application does not have to forcibily use libwimaxll and can talk 53 * the generic netlink protocol directly if desired. 54 * 55 * Remember this is a very low level API that will to provide all of 56 * WiMAX features. Other daemons and services running in user space 57 * are the expected clients of it. They offer a higher level API that 58 * applications should use (an example of this is the Intel's WiMAX 59 * Network Service for the i2400m). 60 * 61 * DESIGN 62 * 63 * Although not set on final stone, this very basic interface is 64 * mostly completed. Remember this is meant to grow as new common 65 * operations are decided upon. New operations will be added to the 66 * interface, intent being on keeping backwards compatibility as much 67 * as possible. 68 * 69 * This layer implements a set of calls to control a WiMAX device, 70 * exposing a frontend to the rest of the kernel and user space (via 71 * generic netlink) and a backend implementation in the driver through 72 * function pointers. 73 * 74 * WiMAX devices have a state, and a kernel-only API allows the 75 * drivers to manipulate that state. State transitions are atomic, and 76 * only some of them are allowed (see `enum wimax_st`). 77 * 78 * Most API calls will set the state automatically; in most cases 79 * drivers have to only report state changes due to external 80 * conditions. 81 * 82 * All API operations are 'atomic', serialized thorough a mutex in the 83 * `struct wimax_dev`. 84 * 85 * EXPORTING TO USER SPACE THROUGH GENERIC NETLINK 86 * 87 * The API is exported to user space using generic netlink (other 88 * methods can be added as needed). 89 * 90 * There is a Generic Netlink Family named "WiMAX", where interfaces 91 * supporting the WiMAX interface receive commands and broadcast their 92 * signals over a multicast group named "msg". 93 * 94 * Mapping to the source/destination interface is done by an interface 95 * index attribute. 96 * 97 * For user-to-kernel traffic (commands) we use a function call 98 * marshalling mechanism, where a message X with attributes A, B, C 99 * sent from user space to kernel space means executing the WiMAX API 100 * call wimax_X(A, B, C), sending the results back as a message. 101 * 102 * Kernel-to-user (notifications or signals) communication is sent 103 * over multicast groups. This allows to have multiple applications 104 * monitoring them. 105 * 106 * Each command/signal gets assigned it's own attribute policy. This 107 * way the validator will verify that all the attributes in there are 108 * only the ones that should be for each command/signal. Thing of an 109 * attribute mapping to a type+argumentname for each command/signal. 110 * 111 * If we had a single policy for *all* commands/signals, after running 112 * the validator we'd have to check "does this attribute belong in 113 * here"? for each one. It can be done manually, but it's just easier 114 * to have the validator do that job with multiple policies. As well, 115 * it makes it easier to later expand each command/signal signature 116 * without affecting others and keeping the namespace more or less 117 * sane. Not that it is too complicated, but it makes it even easier. 118 * 119 * No state information is maintained in the kernel for each user 120 * space connection (the connection is stateless). 121 * 122 * TESTING FOR THE INTERFACE AND VERSIONING 123 * 124 * If network interface X is a WiMAX device, there will be a Generic 125 * Netlink family named "WiMAX X" and the device will present a 126 * "wimax" directory in it's network sysfs directory 127 * (/sys/class/net/DEVICE/wimax) [used by HAL]. 128 * 129 * The inexistence of any of these means the device does not support 130 * this WiMAX API. 131 * 132 * By querying the generic netlink controller, versioning information 133 * and the multicast groups available can be found. Applications using 134 * the interface can either rely on that or use the generic netlink 135 * controller to figure out which generic netlink commands/signals are 136 * supported. 137 * 138 * NOTE: this versioning is a last resort to avoid hard 139 * incompatibilities. It is the intention of the design of this 140 * stack not to introduce backward incompatible changes. 141 * 142 * The version code has to fit in one byte (restrictions imposed by 143 * generic netlink); we use `version / 10` for the major version and 144 * `version % 10` for the minor. This gives 9 minors for each major 145 * and 25 majors. 146 * 147 * The version change protocol is as follow: 148 * 149 * - Major versions: needs to be increased if an existing message/API 150 * call is changed or removed. Doesn't need to be changed if a new 151 * message is added. 152 * 153 * - Minor version: needs to be increased if new messages/API calls are 154 * being added or some other consideration that doesn't impact the 155 * user-kernel interface too much (like some kind of bug fix) and 156 * that is kind of left up in the air to common sense. 157 * 158 * User space code should not try to work if the major version it was 159 * compiled for differs from what the kernel offers. As well, if the 160 * minor version of the kernel interface is lower than the one user 161 * space is expecting (the one it was compiled for), the kernel 162 * might be missing API calls; user space shall be ready to handle 163 * said condition. Use the generic netlink controller operations to 164 * find which ones are supported and which not. 165 * 166 * libwimaxll:wimaxll_open() takes care of checking versions. 167 * 168 * THE OPERATIONS: 169 * 170 * Each operation is defined in its on file (drivers/net/wimax/op-*.c) 171 * for clarity. The parts needed for an operation are: 172 * 173 * - a function pointer in `struct wimax_dev`: optional, as the 174 * operation might be implemented by the stack and not by the 175 * driver. 176 * 177 * All function pointers are named wimax_dev->op_*(), and drivers 178 * must implement them except where noted otherwise. 179 * 180 * - When exported to user space, a `struct nla_policy` to define the 181 * attributes of the generic netlink command and a `struct genl_ops` 182 * to define the operation. 183 * 184 * All the declarations for the operation codes (WIMAX_GNL_OP_<NAME>) 185 * and generic netlink attributes (WIMAX_GNL_<NAME>_*) are declared in 186 * include/linux/wimax.h; this file is intended to be cloned by user 187 * space to gain access to those declarations. 188 * 189 * A few caveats to remember: 190 * 191 * - Need to define attribute numbers starting in 1; otherwise it 192 * fails. 193 * 194 * - the `struct genl_family` requires a maximum attribute id; when 195 * defining the `struct nla_policy` for each message, it has to have 196 * an array size of WIMAX_GNL_ATTR_MAX+1. 197 * 198 * The op_*() function pointers will not be called if the wimax_dev is 199 * in a state <= %WIMAX_ST_UNINITIALIZED. The exception is: 200 * 201 * - op_reset: can be called at any time after wimax_dev_add() has 202 * been called. 203 * 204 * THE PIPE INTERFACE: 205 * 206 * This interface is kept intentionally simple. The driver can send 207 * and receive free-form messages to/from user space through a 208 * pipe. See drivers/net/wimax/op-msg.c for details. 209 * 210 * The kernel-to-user messages are sent with 211 * wimax_msg(). user-to-kernel messages are delivered via 212 * wimax_dev->op_msg_from_user(). 213 * 214 * RFKILL: 215 * 216 * RFKILL support is built into the wimax_dev layer; the driver just 217 * needs to call wimax_report_rfkill_{hw,sw}() to inform of changes in 218 * the hardware or software RF kill switches. When the stack wants to 219 * turn the radio off, it will call wimax_dev->op_rfkill_sw_toggle(), 220 * which the driver implements. 221 * 222 * User space can set the software RF Kill switch by calling 223 * wimax_rfkill(). 224 * 225 * The code for now only supports devices that don't require polling; 226 * If the device needs to be polled, create a self-rearming delayed 227 * work struct for polling or look into adding polled support to the 228 * WiMAX stack. 229 * 230 * When initializing the hardware (_probe), after calling 231 * wimax_dev_add(), query the device for it's RF Kill switches status 232 * and feed it back to the WiMAX stack using 233 * wimax_report_rfkill_{hw,sw}(). If any switch is missing, always 234 * report it as ON. 235 * 236 * NOTE: the wimax stack uses an inverted terminology to that of the 237 * RFKILL subsystem: 238 * 239 * - ON: radio is ON, RFKILL is DISABLED or OFF. 240 * - OFF: radio is OFF, RFKILL is ENABLED or ON. 241 * 242 * MISCELLANEOUS OPS: 243 * 244 * wimax_reset() can be used to reset the device to power on state; by 245 * default it issues a warm reset that maintains the same device 246 * node. If that is not possible, it falls back to a cold reset 247 * (device reconnect). The driver implements the backend to this 248 * through wimax_dev->op_reset(). 249 */ 250 251#ifndef __NET__WIMAX_H__ 252#define __NET__WIMAX_H__ 253#ifdef __KERNEL__ 254 255#include <linux/wimax.h> 256#include <net/genetlink.h> 257#include <linux/netdevice.h> 258 259struct net_device; 260struct genl_info; 261struct wimax_dev; 262 263/** 264 * struct wimax_dev - Generic WiMAX device 265 * 266 * @net_dev: [fill] Pointer to the &struct net_device this WiMAX 267 * device implements. 268 * 269 * @op_msg_from_user: [fill] Driver-specific operation to 270 * handle a raw message from user space to the driver. The 271 * driver can send messages to user space using with 272 * wimax_msg_to_user(). 273 * 274 * @op_rfkill_sw_toggle: [fill] Driver-specific operation to act on 275 * userspace (or any other agent) requesting the WiMAX device to 276 * change the RF Kill software switch (WIMAX_RF_ON or 277 * WIMAX_RF_OFF). 278 * If such hardware support is not present, it is assumed the 279 * radio cannot be switched off and it is always on (and the stack 280 * will error out when trying to switch it off). In such case, 281 * this function pointer can be left as NULL. 282 * 283 * @op_reset: [fill] Driver specific operation to reset the 284 * device. 285 * This operation should always attempt first a warm reset that 286 * does not disconnect the device from the bus and return 0. 287 * If that fails, it should resort to some sort of cold or bus 288 * reset (even if it implies a bus disconnection and device 289 * dissapearance). In that case, -ENODEV should be returned to 290 * indicate the device is gone. 291 * This operation has to be synchronous, and return only when the 292 * reset is complete. In case of having had to resort to bus/cold 293 * reset implying a device disconnection, the call is allowed to 294 * return inmediately. 295 * NOTE: wimax_dev->mutex is NOT locked when this op is being 296 * called; however, wimax_dev->mutex_reset IS locked to ensure 297 * serialization of calls to wimax_reset(). 298 * See wimax_reset()'s documentation. 299 * 300 * @name: [fill] A way to identify this device. We need to register a 301 * name with many subsystems (rfkill, workqueue creation, etc). 302 * We can't use the network device name as that 303 * might change and in some instances we don't know it yet (until 304 * we don't call register_netdev()). So we generate an unique one 305 * using the driver name and device bus id, place it here and use 306 * it across the board. Recommended naming: 307 * DRIVERNAME-BUSNAME:BUSID (dev->bus->name, dev->bus_id). 308 * 309 * @id_table_node: [private] link to the list of wimax devices kept by 310 * id-table.c. Protected by it's own spinlock. 311 * 312 * @mutex: [private] Serializes all concurrent access and execution of 313 * operations. 314 * 315 * @mutex_reset: [private] Serializes reset operations. Needs to be a 316 * different mutex because as part of the reset operation, the 317 * driver has to call back into the stack to do things such as 318 * state change, that require wimax_dev->mutex. 319 * 320 * @state: [private] Current state of the WiMAX device. 321 * 322 * @rfkill: [private] integration into the RF-Kill infrastructure. 323 * 324 * @rf_sw: [private] State of the software radio switch (OFF/ON) 325 * 326 * @rf_hw: [private] State of the hardware radio switch (OFF/ON) 327 * 328 * @debugfs_dentry: [private] Used to hook up a debugfs entry. This 329 * shows up in the debugfs root as wimax\:DEVICENAME. 330 * 331 * Description: 332 * This structure defines a common interface to access all WiMAX 333 * devices from different vendors and provides a common API as well as 334 * a free-form device-specific messaging channel. 335 * 336 * Usage: 337 * 1. Embed a &struct wimax_dev at *the beginning* the network 338 * device structure so that netdev_priv() points to it. 339 * 340 * 2. memset() it to zero 341 * 342 * 3. Initialize with wimax_dev_init(). This will leave the WiMAX 343 * device in the %__WIMAX_ST_NULL state. 344 * 345 * 4. Fill all the fields marked with [fill]; once called 346 * wimax_dev_add(), those fields CANNOT be modified. 347 * 348 * 5. Call wimax_dev_add() *after* registering the network 349 * device. This will leave the WiMAX device in the %WIMAX_ST_DOWN 350 * state. 351 * Protect the driver's net_device->open() against succeeding if 352 * the wimax device state is lower than %WIMAX_ST_DOWN. 353 * 354 * 6. Select when the device is going to be turned on/initialized; 355 * for example, it could be initialized on 'ifconfig up' (when the 356 * netdev op 'open()' is called on the driver). 357 * 358 * When the device is initialized (at `ifconfig up` time, or right 359 * after calling wimax_dev_add() from _probe(), make sure the 360 * following steps are taken 361 * 362 * a. Move the device to %WIMAX_ST_UNINITIALIZED. This is needed so 363 * some API calls that shouldn't work until the device is ready 364 * can be blocked. 365 * 366 * b. Initialize the device. Make sure to turn the SW radio switch 367 * off and move the device to state %WIMAX_ST_RADIO_OFF when 368 * done. When just initialized, a device should be left in RADIO 369 * OFF state until user space devices to turn it on. 370 * 371 * c. Query the device for the state of the hardware rfkill switch 372 * and call wimax_rfkill_report_hw() and wimax_rfkill_report_sw() 373 * as needed. See below. 374 * 375 * wimax_dev_rm() undoes before unregistering the network device. Once 376 * wimax_dev_add() is called, the driver can get called on the 377 * wimax_dev->op_* function pointers 378 * 379 * CONCURRENCY: 380 * 381 * The stack provides a mutex for each device that will disallow API 382 * calls happening concurrently; thus, op calls into the driver 383 * through the wimax_dev->op*() function pointers will always be 384 * serialized and *never* concurrent. 385 * 386 * For locking, take wimax_dev->mutex is taken; (most) operations in 387 * the API have to check for wimax_dev_is_ready() to return 0 before 388 * continuing (this is done internally). 389 * 390 * REFERENCE COUNTING: 391 * 392 * The WiMAX device is reference counted by the associated network 393 * device. The only operation that can be used to reference the device 394 * is wimax_dev_get_by_genl_info(), and the reference it acquires has 395 * to be released with dev_put(wimax_dev->net_dev). 396 * 397 * RFKILL: 398 * 399 * At startup, both HW and SW radio switchess are assumed to be off. 400 * 401 * At initialization time [after calling wimax_dev_add()], have the 402 * driver query the device for the status of the software and hardware 403 * RF kill switches and call wimax_report_rfkill_hw() and 404 * wimax_rfkill_report_sw() to indicate their state. If any is 405 * missing, just call it to indicate it is ON (radio always on). 406 * 407 * Whenever the driver detects a change in the state of the RF kill 408 * switches, it should call wimax_report_rfkill_hw() or 409 * wimax_report_rfkill_sw() to report it to the stack. 410 */ 411struct wimax_dev { 412 struct net_device *net_dev; 413 struct list_head id_table_node; 414 struct mutex mutex; /* Protects all members and API calls */ 415 struct mutex mutex_reset; 416 enum wimax_st state; 417 418 int (*op_msg_from_user)(struct wimax_dev *wimax_dev, 419 const char *, 420 const void *, size_t, 421 const struct genl_info *info); 422 int (*op_rfkill_sw_toggle)(struct wimax_dev *wimax_dev, 423 enum wimax_rf_state); 424 int (*op_reset)(struct wimax_dev *wimax_dev); 425 426 struct rfkill *rfkill; 427 struct input_dev *rfkill_input; 428 unsigned rf_hw; 429 unsigned rf_sw; 430 char name[32]; 431 432 struct dentry *debugfs_dentry; 433}; 434 435 436 437/* 438 * WiMAX stack public API for device drivers 439 * ----------------------------------------- 440 * 441 * These functions are not exported to user space. 442 */ 443extern void wimax_dev_init(struct wimax_dev *); 444extern int wimax_dev_add(struct wimax_dev *, struct net_device *); 445extern void wimax_dev_rm(struct wimax_dev *); 446 447static inline 448struct wimax_dev *net_dev_to_wimax(struct net_device *net_dev) 449{ 450 return netdev_priv(net_dev); 451} 452 453static inline 454struct device *wimax_dev_to_dev(struct wimax_dev *wimax_dev) 455{ 456 return wimax_dev->net_dev->dev.parent; 457} 458 459extern void wimax_state_change(struct wimax_dev *, enum wimax_st); 460extern enum wimax_st wimax_state_get(struct wimax_dev *); 461 462/* 463 * Radio Switch state reporting. 464 * 465 * enum wimax_rf_state is declared in linux/wimax.h so the exports 466 * to user space can use it. 467 */ 468extern void wimax_report_rfkill_hw(struct wimax_dev *, enum wimax_rf_state); 469extern void wimax_report_rfkill_sw(struct wimax_dev *, enum wimax_rf_state); 470 471 472/* 473 * Free-form messaging to/from user space 474 * 475 * Sending a message: 476 * 477 * wimax_msg(wimax_dev, pipe_name, buf, buf_size, GFP_KERNEL); 478 * 479 * Broken up: 480 * 481 * skb = wimax_msg_alloc(wimax_dev, pipe_name, buf_size, GFP_KERNEL); 482 * ...fill up skb... 483 * wimax_msg_send(wimax_dev, pipe_name, skb); 484 * 485 * Be sure not to modify skb->data in the middle (ie: don't use 486 * skb_push()/skb_pull()/skb_reserve() on the skb). 487 * 488 * "pipe_name" is any string, than can be interpreted as the name of 489 * the pipe or destinatary; the interpretation of it is driver 490 * specific, so the recipient can multiplex it as wished. It can be 491 * NULL, it won't be used - an example is using a "diagnostics" tag to 492 * send diagnostics information that a device-specific diagnostics 493 * tool would be interested in. 494 */ 495extern struct sk_buff *wimax_msg_alloc(struct wimax_dev *, const char *, 496 const void *, size_t, gfp_t); 497extern int wimax_msg_send(struct wimax_dev *, struct sk_buff *); 498extern int wimax_msg(struct wimax_dev *, const char *, 499 const void *, size_t, gfp_t); 500 501extern const void *wimax_msg_data_len(struct sk_buff *, size_t *); 502extern const void *wimax_msg_data(struct sk_buff *); 503extern ssize_t wimax_msg_len(struct sk_buff *); 504 505 506/* 507 * WiMAX stack user space API 508 * -------------------------- 509 * 510 * This API is what gets exported to user space for general 511 * operations. As well, they can be called from within the kernel, 512 * (with a properly referenced `struct wimax_dev`). 513 * 514 * Properly referenced means: the 'struct net_device' that embeds the 515 * device's control structure and (as such) the 'struct wimax_dev' is 516 * referenced by the caller. 517 */ 518extern int wimax_rfkill(struct wimax_dev *, enum wimax_rf_state); 519extern int wimax_reset(struct wimax_dev *); 520 521#else 522/* You might be looking for linux/wimax.h */ 523#error This file should not be included from user space. 524#endif /* #ifdef __KERNEL__ */ 525#endif /* #ifndef __NET__WIMAX_H__ */ 526