1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * Surface System Aggregator Module (SSAM) bus and client-device subsystem.
4 *
5 * Main interface for the surface-aggregator bus, surface-aggregator client
6 * devices, and respective drivers building on top of the SSAM controller.
7 * Provides support for non-platform/non-ACPI SSAM clients via dedicated
8 * subsystem.
9 *
10 * Copyright (C) 2019-2021 Maximilian Luz <luzmaximilian@gmail.com>
11 */
12
13 #ifndef _LINUX_SURFACE_AGGREGATOR_DEVICE_H
14 #define _LINUX_SURFACE_AGGREGATOR_DEVICE_H
15
16 #include <linux/device.h>
17 #include <linux/mod_devicetable.h>
18 #include <linux/property.h>
19 #include <linux/types.h>
20
21 #include <linux/surface_aggregator/controller.h>
22
23
24 /* -- Surface System Aggregator Module bus. --------------------------------- */
25
26 /**
27 * enum ssam_device_domain - SAM device domain.
28 * @SSAM_DOMAIN_VIRTUAL: Virtual device.
29 * @SSAM_DOMAIN_SERIALHUB: Physical device connected via Surface Serial Hub.
30 */
31 enum ssam_device_domain {
32 SSAM_DOMAIN_VIRTUAL = 0x00,
33 SSAM_DOMAIN_SERIALHUB = 0x01,
34 };
35
36 /**
37 * enum ssam_virtual_tc - Target categories for the virtual SAM domain.
38 * @SSAM_VIRTUAL_TC_HUB: Device hub category.
39 */
40 enum ssam_virtual_tc {
41 SSAM_VIRTUAL_TC_HUB = 0x00,
42 };
43
44 /**
45 * struct ssam_device_uid - Unique identifier for SSAM device.
46 * @domain: Domain of the device.
47 * @category: Target category of the device.
48 * @target: Target ID of the device.
49 * @instance: Instance ID of the device.
50 * @function: Sub-function of the device. This field can be used to split a
51 * single SAM device into multiple virtual subdevices to separate
52 * different functionality of that device and allow one driver per
53 * such functionality.
54 */
55 struct ssam_device_uid {
56 u8 domain;
57 u8 category;
58 u8 target;
59 u8 instance;
60 u8 function;
61 };
62
63 /*
64 * Special values for device matching.
65 *
66 * These values are intended to be used with SSAM_DEVICE(), SSAM_VDEV(), and
67 * SSAM_SDEV() exclusively. Specifically, they are used to initialize the
68 * match_flags member of the device ID structure. Do not use them directly
69 * with struct ssam_device_id or struct ssam_device_uid.
70 */
71 #define SSAM_SSH_TID_ANY 0xffff
72 #define SSAM_SSH_IID_ANY 0xffff
73 #define SSAM_SSH_FUN_ANY 0xffff
74
75 /**
76 * SSAM_DEVICE() - Initialize a &struct ssam_device_id with the given
77 * parameters.
78 * @d: Domain of the device.
79 * @cat: Target category of the device.
80 * @tid: Target ID of the device.
81 * @iid: Instance ID of the device.
82 * @fun: Sub-function of the device.
83 *
84 * Initializes a &struct ssam_device_id with the given parameters. See &struct
85 * ssam_device_uid for details regarding the parameters. The special values
86 * %SSAM_SSH_TID_ANY, %SSAM_SSH_IID_ANY, and %SSAM_SSH_FUN_ANY can be used to specify that
87 * matching should ignore target ID, instance ID, and/or sub-function,
88 * respectively. This macro initializes the ``match_flags`` field based on the
89 * given parameters.
90 *
91 * Note: The parameters @d and @cat must be valid &u8 values, the parameters
92 * @tid, @iid, and @fun must be either valid &u8 values or %SSAM_SSH_TID_ANY,
93 * %SSAM_SSH_IID_ANY, or %SSAM_SSH_FUN_ANY, respectively. Other non-&u8 values are not
94 * allowed.
95 */
96 #define SSAM_DEVICE(d, cat, tid, iid, fun) \
97 .match_flags = (((tid) != SSAM_SSH_TID_ANY) ? SSAM_MATCH_TARGET : 0) \
98 | (((iid) != SSAM_SSH_IID_ANY) ? SSAM_MATCH_INSTANCE : 0) \
99 | (((fun) != SSAM_SSH_FUN_ANY) ? SSAM_MATCH_FUNCTION : 0), \
100 .domain = d, \
101 .category = cat, \
102 .target = __builtin_choose_expr((tid) != SSAM_SSH_TID_ANY, (tid), 0), \
103 .instance = __builtin_choose_expr((iid) != SSAM_SSH_IID_ANY, (iid), 0), \
104 .function = __builtin_choose_expr((fun) != SSAM_SSH_FUN_ANY, (fun), 0)
105
106 /**
107 * SSAM_VDEV() - Initialize a &struct ssam_device_id as virtual device with
108 * the given parameters.
109 * @cat: Target category of the device.
110 * @tid: Target ID of the device.
111 * @iid: Instance ID of the device.
112 * @fun: Sub-function of the device.
113 *
114 * Initializes a &struct ssam_device_id with the given parameters in the
115 * virtual domain. See &struct ssam_device_uid for details regarding the
116 * parameters. The special values %SSAM_SSH_TID_ANY, %SSAM_SSH_IID_ANY, and
117 * %SSAM_SSH_FUN_ANY can be used to specify that matching should ignore target ID,
118 * instance ID, and/or sub-function, respectively. This macro initializes the
119 * ``match_flags`` field based on the given parameters.
120 *
121 * Note: The parameter @cat must be a valid &u8 value, the parameters @tid,
122 * @iid, and @fun must be either valid &u8 values or %SSAM_SSH_TID_ANY,
123 * %SSAM_SSH_IID_ANY, or %SSAM_SSH_FUN_ANY, respectively. Other non-&u8 values are not
124 * allowed.
125 */
126 #define SSAM_VDEV(cat, tid, iid, fun) \
127 SSAM_DEVICE(SSAM_DOMAIN_VIRTUAL, SSAM_VIRTUAL_TC_##cat, SSAM_SSH_TID_##tid, iid, fun)
128
129 /**
130 * SSAM_SDEV() - Initialize a &struct ssam_device_id as physical SSH device
131 * with the given parameters.
132 * @cat: Target category of the device.
133 * @tid: Target ID of the device.
134 * @iid: Instance ID of the device.
135 * @fun: Sub-function of the device.
136 *
137 * Initializes a &struct ssam_device_id with the given parameters in the SSH
138 * domain. See &struct ssam_device_uid for details regarding the parameters.
139 * The special values %SSAM_SSH_TID_ANY, %SSAM_SSH_IID_ANY, and
140 * %SSAM_SSH_FUN_ANY can be used to specify that matching should ignore target
141 * ID, instance ID, and/or sub-function, respectively. This macro initializes
142 * the ``match_flags`` field based on the given parameters.
143 *
144 * Note: The parameter @cat must be a valid &u8 value, the parameters @tid,
145 * @iid, and @fun must be either valid &u8 values or %SSAM_SSH_TID_ANY,
146 * %SSAM_SSH_IID_ANY, or %SSAM_SSH_FUN_ANY, respectively. Other non-&u8 values
147 * are not allowed.
148 */
149 #define SSAM_SDEV(cat, tid, iid, fun) \
150 SSAM_DEVICE(SSAM_DOMAIN_SERIALHUB, SSAM_SSH_TC_##cat, SSAM_SSH_TID_##tid, iid, fun)
151
152 /*
153 * enum ssam_device_flags - Flags for SSAM client devices.
154 * @SSAM_DEVICE_HOT_REMOVED_BIT:
155 * The device has been hot-removed. Further communication with it may time
156 * out and should be avoided.
157 */
158 enum ssam_device_flags {
159 SSAM_DEVICE_HOT_REMOVED_BIT = 0,
160 };
161
162 /**
163 * struct ssam_device - SSAM client device.
164 * @dev: Driver model representation of the device.
165 * @ctrl: SSAM controller managing this device.
166 * @uid: UID identifying the device.
167 * @flags: Device state flags, see &enum ssam_device_flags.
168 */
169 struct ssam_device {
170 struct device dev;
171 struct ssam_controller *ctrl;
172
173 struct ssam_device_uid uid;
174
175 unsigned long flags;
176 };
177
178 /**
179 * struct ssam_device_driver - SSAM client device driver.
180 * @driver: Base driver model structure.
181 * @match_table: Match table specifying which devices the driver should bind to.
182 * @probe: Called when the driver is being bound to a device.
183 * @remove: Called when the driver is being unbound from the device.
184 */
185 struct ssam_device_driver {
186 struct device_driver driver;
187
188 const struct ssam_device_id *match_table;
189
190 int (*probe)(struct ssam_device *sdev);
191 void (*remove)(struct ssam_device *sdev);
192 };
193
194 #ifdef CONFIG_SURFACE_AGGREGATOR_BUS
195
196 extern struct bus_type ssam_bus_type;
197 extern const struct device_type ssam_device_type;
198
199 /**
200 * is_ssam_device() - Check if the given device is a SSAM client device.
201 * @d: The device to test the type of.
202 *
203 * Return: Returns %true if the specified device is of type &struct
204 * ssam_device, i.e. the device type points to %ssam_device_type, and %false
205 * otherwise.
206 */
is_ssam_device(struct device * d)207 static inline bool is_ssam_device(struct device *d)
208 {
209 return d->type == &ssam_device_type;
210 }
211
212 #else /* CONFIG_SURFACE_AGGREGATOR_BUS */
213
is_ssam_device(struct device * d)214 static inline bool is_ssam_device(struct device *d)
215 {
216 return false;
217 }
218
219 #endif /* CONFIG_SURFACE_AGGREGATOR_BUS */
220
221 /**
222 * to_ssam_device() - Casts the given device to a SSAM client device.
223 * @d: The device to cast.
224 *
225 * Casts the given &struct device to a &struct ssam_device. The caller has to
226 * ensure that the given device is actually enclosed in a &struct ssam_device,
227 * e.g. by calling is_ssam_device().
228 *
229 * Return: Returns a pointer to the &struct ssam_device wrapping the given
230 * device @d.
231 */
232 #define to_ssam_device(d) container_of_const(d, struct ssam_device, dev)
233
234 /**
235 * to_ssam_device_driver() - Casts the given device driver to a SSAM client
236 * device driver.
237 * @d: The driver to cast.
238 *
239 * Casts the given &struct device_driver to a &struct ssam_device_driver. The
240 * caller has to ensure that the given driver is actually enclosed in a
241 * &struct ssam_device_driver.
242 *
243 * Return: Returns the pointer to the &struct ssam_device_driver wrapping the
244 * given device driver @d.
245 */
246 #define to_ssam_device_driver(d) container_of_const(d, struct ssam_device_driver, driver)
247
248 const struct ssam_device_id *ssam_device_id_match(const struct ssam_device_id *table,
249 const struct ssam_device_uid uid);
250
251 const struct ssam_device_id *ssam_device_get_match(const struct ssam_device *dev);
252
253 const void *ssam_device_get_match_data(const struct ssam_device *dev);
254
255 struct ssam_device *ssam_device_alloc(struct ssam_controller *ctrl,
256 struct ssam_device_uid uid);
257
258 int ssam_device_add(struct ssam_device *sdev);
259 void ssam_device_remove(struct ssam_device *sdev);
260
261 /**
262 * ssam_device_mark_hot_removed() - Mark the given device as hot-removed.
263 * @sdev: The device to mark as hot-removed.
264 *
265 * Mark the device as having been hot-removed. This signals drivers using the
266 * device that communication with the device should be avoided and may lead to
267 * timeouts.
268 */
ssam_device_mark_hot_removed(struct ssam_device * sdev)269 static inline void ssam_device_mark_hot_removed(struct ssam_device *sdev)
270 {
271 dev_dbg(&sdev->dev, "marking device as hot-removed\n");
272 set_bit(SSAM_DEVICE_HOT_REMOVED_BIT, &sdev->flags);
273 }
274
275 /**
276 * ssam_device_is_hot_removed() - Check if the given device has been
277 * hot-removed.
278 * @sdev: The device to check.
279 *
280 * Checks if the given device has been marked as hot-removed. See
281 * ssam_device_mark_hot_removed() for more details.
282 *
283 * Return: Returns ``true`` if the device has been marked as hot-removed.
284 */
ssam_device_is_hot_removed(struct ssam_device * sdev)285 static inline bool ssam_device_is_hot_removed(struct ssam_device *sdev)
286 {
287 return test_bit(SSAM_DEVICE_HOT_REMOVED_BIT, &sdev->flags);
288 }
289
290 /**
291 * ssam_device_get() - Increment reference count of SSAM client device.
292 * @sdev: The device to increment the reference count of.
293 *
294 * Increments the reference count of the given SSAM client device by
295 * incrementing the reference count of the enclosed &struct device via
296 * get_device().
297 *
298 * See ssam_device_put() for the counter-part of this function.
299 *
300 * Return: Returns the device provided as input.
301 */
ssam_device_get(struct ssam_device * sdev)302 static inline struct ssam_device *ssam_device_get(struct ssam_device *sdev)
303 {
304 return sdev ? to_ssam_device(get_device(&sdev->dev)) : NULL;
305 }
306
307 /**
308 * ssam_device_put() - Decrement reference count of SSAM client device.
309 * @sdev: The device to decrement the reference count of.
310 *
311 * Decrements the reference count of the given SSAM client device by
312 * decrementing the reference count of the enclosed &struct device via
313 * put_device().
314 *
315 * See ssam_device_get() for the counter-part of this function.
316 */
ssam_device_put(struct ssam_device * sdev)317 static inline void ssam_device_put(struct ssam_device *sdev)
318 {
319 if (sdev)
320 put_device(&sdev->dev);
321 }
322
323 /**
324 * ssam_device_get_drvdata() - Get driver-data of SSAM client device.
325 * @sdev: The device to get the driver-data from.
326 *
327 * Return: Returns the driver-data of the given device, previously set via
328 * ssam_device_set_drvdata().
329 */
ssam_device_get_drvdata(struct ssam_device * sdev)330 static inline void *ssam_device_get_drvdata(struct ssam_device *sdev)
331 {
332 return dev_get_drvdata(&sdev->dev);
333 }
334
335 /**
336 * ssam_device_set_drvdata() - Set driver-data of SSAM client device.
337 * @sdev: The device to set the driver-data of.
338 * @data: The data to set the device's driver-data pointer to.
339 */
ssam_device_set_drvdata(struct ssam_device * sdev,void * data)340 static inline void ssam_device_set_drvdata(struct ssam_device *sdev, void *data)
341 {
342 dev_set_drvdata(&sdev->dev, data);
343 }
344
345 int __ssam_device_driver_register(struct ssam_device_driver *d, struct module *o);
346 void ssam_device_driver_unregister(struct ssam_device_driver *d);
347
348 /**
349 * ssam_device_driver_register() - Register a SSAM client device driver.
350 * @drv: The driver to register.
351 */
352 #define ssam_device_driver_register(drv) \
353 __ssam_device_driver_register(drv, THIS_MODULE)
354
355 /**
356 * module_ssam_device_driver() - Helper macro for SSAM device driver
357 * registration.
358 * @drv: The driver managed by this module.
359 *
360 * Helper macro to register a SSAM device driver via module_init() and
361 * module_exit(). This macro may only be used once per module and replaces the
362 * aforementioned definitions.
363 */
364 #define module_ssam_device_driver(drv) \
365 module_driver(drv, ssam_device_driver_register, \
366 ssam_device_driver_unregister)
367
368
369 /* -- Helpers for controller and hub devices. ------------------------------- */
370
371 #ifdef CONFIG_SURFACE_AGGREGATOR_BUS
372
373 int __ssam_register_clients(struct device *parent, struct ssam_controller *ctrl,
374 struct fwnode_handle *node);
375 void ssam_remove_clients(struct device *dev);
376
377 #else /* CONFIG_SURFACE_AGGREGATOR_BUS */
378
__ssam_register_clients(struct device * parent,struct ssam_controller * ctrl,struct fwnode_handle * node)379 static inline int __ssam_register_clients(struct device *parent, struct ssam_controller *ctrl,
380 struct fwnode_handle *node)
381 {
382 return 0;
383 }
384
ssam_remove_clients(struct device * dev)385 static inline void ssam_remove_clients(struct device *dev) {}
386
387 #endif /* CONFIG_SURFACE_AGGREGATOR_BUS */
388
389 /**
390 * ssam_register_clients() - Register all client devices defined under the
391 * given parent device.
392 * @dev: The parent device under which clients should be registered.
393 * @ctrl: The controller with which client should be registered.
394 *
395 * Register all clients that have via firmware nodes been defined as children
396 * of the given (parent) device. The respective child firmware nodes will be
397 * associated with the correspondingly created child devices.
398 *
399 * The given controller will be used to instantiate the new devices. See
400 * ssam_device_add() for details.
401 *
402 * Return: Returns zero on success, nonzero on failure.
403 */
ssam_register_clients(struct device * dev,struct ssam_controller * ctrl)404 static inline int ssam_register_clients(struct device *dev, struct ssam_controller *ctrl)
405 {
406 return __ssam_register_clients(dev, ctrl, dev_fwnode(dev));
407 }
408
409 /**
410 * ssam_device_register_clients() - Register all client devices defined under
411 * the given SSAM parent device.
412 * @sdev: The parent device under which clients should be registered.
413 *
414 * Register all clients that have via firmware nodes been defined as children
415 * of the given (parent) device. The respective child firmware nodes will be
416 * associated with the correspondingly created child devices.
417 *
418 * The controller used by the parent device will be used to instantiate the new
419 * devices. See ssam_device_add() for details.
420 *
421 * Return: Returns zero on success, nonzero on failure.
422 */
ssam_device_register_clients(struct ssam_device * sdev)423 static inline int ssam_device_register_clients(struct ssam_device *sdev)
424 {
425 return ssam_register_clients(&sdev->dev, sdev->ctrl);
426 }
427
428
429 /* -- Helpers for client-device requests. ----------------------------------- */
430
431 /**
432 * SSAM_DEFINE_SYNC_REQUEST_CL_N() - Define synchronous client-device SAM
433 * request function with neither argument nor return value.
434 * @name: Name of the generated function.
435 * @spec: Specification (&struct ssam_request_spec_md) defining the request.
436 *
437 * Defines a function executing the synchronous SAM request specified by
438 * @spec, with the request having neither argument nor return value. Device
439 * specifying parameters are not hard-coded, but instead are provided via the
440 * client device, specifically its UID, supplied when calling this function.
441 * The generated function takes care of setting up the request struct, buffer
442 * allocation, as well as execution of the request itself, returning once the
443 * request has been fully completed. The required transport buffer will be
444 * allocated on the stack.
445 *
446 * The generated function is defined as ``static int name(struct ssam_device
447 * *sdev)``, returning the status of the request, which is zero on success and
448 * negative on failure. The ``sdev`` parameter specifies both the target
449 * device of the request and by association the controller via which the
450 * request is sent.
451 *
452 * Refer to ssam_request_do_sync_onstack() for more details on the behavior of
453 * the generated function.
454 */
455 #define SSAM_DEFINE_SYNC_REQUEST_CL_N(name, spec...) \
456 SSAM_DEFINE_SYNC_REQUEST_MD_N(__raw_##name, spec) \
457 static int name(struct ssam_device *sdev) \
458 { \
459 return __raw_##name(sdev->ctrl, sdev->uid.target, \
460 sdev->uid.instance); \
461 }
462
463 /**
464 * SSAM_DEFINE_SYNC_REQUEST_CL_W() - Define synchronous client-device SAM
465 * request function with argument.
466 * @name: Name of the generated function.
467 * @atype: Type of the request's argument.
468 * @spec: Specification (&struct ssam_request_spec_md) defining the request.
469 *
470 * Defines a function executing the synchronous SAM request specified by
471 * @spec, with the request taking an argument of type @atype and having no
472 * return value. Device specifying parameters are not hard-coded, but instead
473 * are provided via the client device, specifically its UID, supplied when
474 * calling this function. The generated function takes care of setting up the
475 * request struct, buffer allocation, as well as execution of the request
476 * itself, returning once the request has been fully completed. The required
477 * transport buffer will be allocated on the stack.
478 *
479 * The generated function is defined as ``static int name(struct ssam_device
480 * *sdev, const atype *arg)``, returning the status of the request, which is
481 * zero on success and negative on failure. The ``sdev`` parameter specifies
482 * both the target device of the request and by association the controller via
483 * which the request is sent. The request's argument is specified via the
484 * ``arg`` pointer.
485 *
486 * Refer to ssam_request_do_sync_onstack() for more details on the behavior of
487 * the generated function.
488 */
489 #define SSAM_DEFINE_SYNC_REQUEST_CL_W(name, atype, spec...) \
490 SSAM_DEFINE_SYNC_REQUEST_MD_W(__raw_##name, atype, spec) \
491 static int name(struct ssam_device *sdev, const atype *arg) \
492 { \
493 return __raw_##name(sdev->ctrl, sdev->uid.target, \
494 sdev->uid.instance, arg); \
495 }
496
497 /**
498 * SSAM_DEFINE_SYNC_REQUEST_CL_R() - Define synchronous client-device SAM
499 * request function with return value.
500 * @name: Name of the generated function.
501 * @rtype: Type of the request's return value.
502 * @spec: Specification (&struct ssam_request_spec_md) defining the request.
503 *
504 * Defines a function executing the synchronous SAM request specified by
505 * @spec, with the request taking no argument but having a return value of
506 * type @rtype. Device specifying parameters are not hard-coded, but instead
507 * are provided via the client device, specifically its UID, supplied when
508 * calling this function. The generated function takes care of setting up the
509 * request struct, buffer allocation, as well as execution of the request
510 * itself, returning once the request has been fully completed. The required
511 * transport buffer will be allocated on the stack.
512 *
513 * The generated function is defined as ``static int name(struct ssam_device
514 * *sdev, rtype *ret)``, returning the status of the request, which is zero on
515 * success and negative on failure. The ``sdev`` parameter specifies both the
516 * target device of the request and by association the controller via which
517 * the request is sent. The request's return value is written to the memory
518 * pointed to by the ``ret`` parameter.
519 *
520 * Refer to ssam_request_do_sync_onstack() for more details on the behavior of
521 * the generated function.
522 */
523 #define SSAM_DEFINE_SYNC_REQUEST_CL_R(name, rtype, spec...) \
524 SSAM_DEFINE_SYNC_REQUEST_MD_R(__raw_##name, rtype, spec) \
525 static int name(struct ssam_device *sdev, rtype *ret) \
526 { \
527 return __raw_##name(sdev->ctrl, sdev->uid.target, \
528 sdev->uid.instance, ret); \
529 }
530
531 /**
532 * SSAM_DEFINE_SYNC_REQUEST_CL_WR() - Define synchronous client-device SAM
533 * request function with argument and return value.
534 * @name: Name of the generated function.
535 * @atype: Type of the request's argument.
536 * @rtype: Type of the request's return value.
537 * @spec: Specification (&struct ssam_request_spec_md) defining the request.
538 *
539 * Defines a function executing the synchronous SAM request specified by @spec,
540 * with the request taking an argument of type @atype and having a return value
541 * of type @rtype. Device specifying parameters are not hard-coded, but instead
542 * are provided via the client device, specifically its UID, supplied when
543 * calling this function. The generated function takes care of setting up the
544 * request struct, buffer allocation, as well as execution of the request
545 * itself, returning once the request has been fully completed. The required
546 * transport buffer will be allocated on the stack.
547 *
548 * The generated function is defined as ``static int name(struct ssam_device
549 * *sdev, const atype *arg, rtype *ret)``, returning the status of the request,
550 * which is zero on success and negative on failure. The ``sdev`` parameter
551 * specifies both the target device of the request and by association the
552 * controller via which the request is sent. The request's argument is
553 * specified via the ``arg`` pointer. The request's return value is written to
554 * the memory pointed to by the ``ret`` parameter.
555 *
556 * Refer to ssam_request_do_sync_onstack() for more details on the behavior of
557 * the generated function.
558 */
559 #define SSAM_DEFINE_SYNC_REQUEST_CL_WR(name, atype, rtype, spec...) \
560 SSAM_DEFINE_SYNC_REQUEST_MD_WR(__raw_##name, atype, rtype, spec) \
561 static int name(struct ssam_device *sdev, const atype *arg, rtype *ret) \
562 { \
563 return __raw_##name(sdev->ctrl, sdev->uid.target, \
564 sdev->uid.instance, arg, ret); \
565 }
566
567
568 /* -- Helpers for client-device notifiers. ---------------------------------- */
569
570 /**
571 * ssam_device_notifier_register() - Register an event notifier for the
572 * specified client device.
573 * @sdev: The device the notifier should be registered on.
574 * @n: The event notifier to register.
575 *
576 * Register an event notifier. Increment the usage counter of the associated
577 * SAM event if the notifier is not marked as an observer. If the event is not
578 * marked as an observer and is currently not enabled, it will be enabled
579 * during this call. If the notifier is marked as an observer, no attempt will
580 * be made at enabling any event and no reference count will be modified.
581 *
582 * Notifiers marked as observers do not need to be associated with one specific
583 * event, i.e. as long as no event matching is performed, only the event target
584 * category needs to be set.
585 *
586 * Return: Returns zero on success, %-ENOSPC if there have already been
587 * %INT_MAX notifiers for the event ID/type associated with the notifier block
588 * registered, %-ENOMEM if the corresponding event entry could not be
589 * allocated, %-ENODEV if the device is marked as hot-removed. If this is the
590 * first time that a notifier block is registered for the specific associated
591 * event, returns the status of the event-enable EC-command.
592 */
ssam_device_notifier_register(struct ssam_device * sdev,struct ssam_event_notifier * n)593 static inline int ssam_device_notifier_register(struct ssam_device *sdev,
594 struct ssam_event_notifier *n)
595 {
596 /*
597 * Note that this check does not provide any guarantees whatsoever as
598 * hot-removal could happen at any point and we can't protect against
599 * it. Nevertheless, if we can detect hot-removal, bail early to avoid
600 * communication timeouts.
601 */
602 if (ssam_device_is_hot_removed(sdev))
603 return -ENODEV;
604
605 return ssam_notifier_register(sdev->ctrl, n);
606 }
607
608 /**
609 * ssam_device_notifier_unregister() - Unregister an event notifier for the
610 * specified client device.
611 * @sdev: The device the notifier has been registered on.
612 * @n: The event notifier to unregister.
613 *
614 * Unregister an event notifier. Decrement the usage counter of the associated
615 * SAM event if the notifier is not marked as an observer. If the usage counter
616 * reaches zero, the event will be disabled.
617 *
618 * In case the device has been marked as hot-removed, the event will not be
619 * disabled on the EC, as in those cases any attempt at doing so may time out.
620 *
621 * Return: Returns zero on success, %-ENOENT if the given notifier block has
622 * not been registered on the controller. If the given notifier block was the
623 * last one associated with its specific event, returns the status of the
624 * event-disable EC-command.
625 */
ssam_device_notifier_unregister(struct ssam_device * sdev,struct ssam_event_notifier * n)626 static inline int ssam_device_notifier_unregister(struct ssam_device *sdev,
627 struct ssam_event_notifier *n)
628 {
629 return __ssam_notifier_unregister(sdev->ctrl, n,
630 !ssam_device_is_hot_removed(sdev));
631 }
632
633 #endif /* _LINUX_SURFACE_AGGREGATOR_DEVICE_H */
634