1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  * Surface System Aggregator Module (SSAM) controller interface.
4  *
5  * Main communication interface for the SSAM EC. Provides a controller
6  * managing access and communication to and from the SSAM EC, as well as main
7  * communication structures and definitions.
8  *
9  * Copyright (C) 2019-2021 Maximilian Luz <luzmaximilian@gmail.com>
10  */
11 
12 #ifndef _LINUX_SURFACE_AGGREGATOR_CONTROLLER_H
13 #define _LINUX_SURFACE_AGGREGATOR_CONTROLLER_H
14 
15 #include <linux/completion.h>
16 #include <linux/device.h>
17 #include <linux/types.h>
18 
19 #include <linux/surface_aggregator/serial_hub.h>
20 
21 
22 /* -- Main data types and definitions --------------------------------------- */
23 
24 /**
25  * enum ssam_event_flags - Flags for enabling/disabling SAM events
26  * @SSAM_EVENT_SEQUENCED: The event will be sent via a sequenced data frame.
27  */
28 enum ssam_event_flags {
29 	SSAM_EVENT_SEQUENCED = BIT(0),
30 };
31 
32 /**
33  * struct ssam_event - SAM event sent from the EC to the host.
34  * @target_category: Target category of the event source. See &enum ssam_ssh_tc.
35  * @target_id:       Target ID of the event source.
36  * @command_id:      Command ID of the event.
37  * @instance_id:     Instance ID of the event source.
38  * @length:          Length of the event payload in bytes.
39  * @data:            Event payload data.
40  */
41 struct ssam_event {
42 	u8 target_category;
43 	u8 target_id;
44 	u8 command_id;
45 	u8 instance_id;
46 	u16 length;
47 	u8 data[];
48 };
49 
50 /**
51  * enum ssam_request_flags - Flags for SAM requests.
52  *
53  * @SSAM_REQUEST_HAS_RESPONSE:
54  *	Specifies that the request expects a response. If not set, the request
55  *	will be directly completed after its underlying packet has been
56  *	transmitted. If set, the request transport system waits for a response
57  *	of the request.
58  *
59  * @SSAM_REQUEST_UNSEQUENCED:
60  *	Specifies that the request should be transmitted via an unsequenced
61  *	packet. If set, the request must not have a response, meaning that this
62  *	flag and the %SSAM_REQUEST_HAS_RESPONSE flag are mutually exclusive.
63  */
64 enum ssam_request_flags {
65 	SSAM_REQUEST_HAS_RESPONSE = BIT(0),
66 	SSAM_REQUEST_UNSEQUENCED  = BIT(1),
67 };
68 
69 /**
70  * struct ssam_request - SAM request description.
71  * @target_category: Category of the request's target. See &enum ssam_ssh_tc.
72  * @target_id:       ID of the request's target.
73  * @command_id:      Command ID of the request.
74  * @instance_id:     Instance ID of the request's target.
75  * @flags:           Flags for the request. See &enum ssam_request_flags.
76  * @length:          Length of the request payload in bytes.
77  * @payload:         Request payload data.
78  *
79  * This struct fully describes a SAM request with payload. It is intended to
80  * help set up the actual transport struct, e.g. &struct ssam_request_sync,
81  * and specifically its raw message data via ssam_request_write_data().
82  */
83 struct ssam_request {
84 	u8 target_category;
85 	u8 target_id;
86 	u8 command_id;
87 	u8 instance_id;
88 	u16 flags;
89 	u16 length;
90 	const u8 *payload;
91 };
92 
93 /**
94  * struct ssam_response - Response buffer for SAM request.
95  * @capacity: Capacity of the buffer, in bytes.
96  * @length:   Length of the actual data stored in the memory pointed to by
97  *            @pointer, in bytes. Set by the transport system.
98  * @pointer:  Pointer to the buffer's memory, storing the response payload data.
99  */
100 struct ssam_response {
101 	size_t capacity;
102 	size_t length;
103 	u8 *pointer;
104 };
105 
106 struct ssam_controller;
107 
108 struct ssam_controller *ssam_get_controller(void);
109 struct ssam_controller *ssam_client_bind(struct device *client);
110 int ssam_client_link(struct ssam_controller *ctrl, struct device *client);
111 
112 struct device *ssam_controller_device(struct ssam_controller *c);
113 
114 struct ssam_controller *ssam_controller_get(struct ssam_controller *c);
115 void ssam_controller_put(struct ssam_controller *c);
116 
117 void ssam_controller_statelock(struct ssam_controller *c);
118 void ssam_controller_stateunlock(struct ssam_controller *c);
119 
120 ssize_t ssam_request_write_data(struct ssam_span *buf,
121 				struct ssam_controller *ctrl,
122 				const struct ssam_request *spec);
123 
124 
125 /* -- Synchronous request interface. ---------------------------------------- */
126 
127 /**
128  * struct ssam_request_sync - Synchronous SAM request struct.
129  * @base:   Underlying SSH request.
130  * @comp:   Completion used to signal full completion of the request. After the
131  *          request has been submitted, this struct may only be modified or
132  *          deallocated after the completion has been signaled.
133  *          request has been submitted,
134  * @resp:   Buffer to store the response.
135  * @status: Status of the request, set after the base request has been
136  *          completed or has failed.
137  */
138 struct ssam_request_sync {
139 	struct ssh_request base;
140 	struct completion comp;
141 	struct ssam_response *resp;
142 	int status;
143 };
144 
145 int ssam_request_sync_alloc(size_t payload_len, gfp_t flags,
146 			    struct ssam_request_sync **rqst,
147 			    struct ssam_span *buffer);
148 
149 void ssam_request_sync_free(struct ssam_request_sync *rqst);
150 
151 int ssam_request_sync_init(struct ssam_request_sync *rqst,
152 			   enum ssam_request_flags flags);
153 
154 /**
155  * ssam_request_sync_set_data - Set message data of a synchronous request.
156  * @rqst: The request.
157  * @ptr:  Pointer to the request message data.
158  * @len:  Length of the request message data.
159  *
160  * Set the request message data of a synchronous request. The provided buffer
161  * needs to live until the request has been completed.
162  */
ssam_request_sync_set_data(struct ssam_request_sync * rqst,u8 * ptr,size_t len)163 static inline void ssam_request_sync_set_data(struct ssam_request_sync *rqst,
164 					      u8 *ptr, size_t len)
165 {
166 	ssh_request_set_data(&rqst->base, ptr, len);
167 }
168 
169 /**
170  * ssam_request_sync_set_resp - Set response buffer of a synchronous request.
171  * @rqst: The request.
172  * @resp: The response buffer.
173  *
174  * Sets the response buffer of a synchronous request. This buffer will store
175  * the response of the request after it has been completed. May be %NULL if no
176  * response is expected.
177  */
ssam_request_sync_set_resp(struct ssam_request_sync * rqst,struct ssam_response * resp)178 static inline void ssam_request_sync_set_resp(struct ssam_request_sync *rqst,
179 					      struct ssam_response *resp)
180 {
181 	rqst->resp = resp;
182 }
183 
184 int ssam_request_sync_submit(struct ssam_controller *ctrl,
185 			     struct ssam_request_sync *rqst);
186 
187 /**
188  * ssam_request_sync_wait - Wait for completion of a synchronous request.
189  * @rqst: The request to wait for.
190  *
191  * Wait for completion and release of a synchronous request. After this
192  * function terminates, the request is guaranteed to have left the transport
193  * system. After successful submission of a request, this function must be
194  * called before accessing the response of the request, freeing the request,
195  * or freeing any of the buffers associated with the request.
196  *
197  * This function must not be called if the request has not been submitted yet
198  * and may lead to a deadlock/infinite wait if a subsequent request submission
199  * fails in that case, due to the completion never triggering.
200  *
201  * Return: Returns the status of the given request, which is set on completion
202  * of the packet. This value is zero on success and negative on failure.
203  */
ssam_request_sync_wait(struct ssam_request_sync * rqst)204 static inline int ssam_request_sync_wait(struct ssam_request_sync *rqst)
205 {
206 	wait_for_completion(&rqst->comp);
207 	return rqst->status;
208 }
209 
210 int ssam_request_sync(struct ssam_controller *ctrl,
211 		      const struct ssam_request *spec,
212 		      struct ssam_response *rsp);
213 
214 int ssam_request_sync_with_buffer(struct ssam_controller *ctrl,
215 				  const struct ssam_request *spec,
216 				  struct ssam_response *rsp,
217 				  struct ssam_span *buf);
218 
219 /**
220  * ssam_request_sync_onstack - Execute a synchronous request on the stack.
221  * @ctrl: The controller via which the request is submitted.
222  * @rqst: The request specification.
223  * @rsp:  The response buffer.
224  * @payload_len: The (maximum) request payload length.
225  *
226  * Allocates a synchronous request with specified payload length on the stack,
227  * fully initializes it via the provided request specification, submits it,
228  * and finally waits for its completion before returning its status. This
229  * helper macro essentially allocates the request message buffer on the stack
230  * and then calls ssam_request_sync_with_buffer().
231  *
232  * Note: The @payload_len parameter specifies the maximum payload length, used
233  * for buffer allocation. The actual payload length may be smaller.
234  *
235  * Return: Returns the status of the request or any failure during setup, i.e.
236  * zero on success and a negative value on failure.
237  */
238 #define ssam_request_sync_onstack(ctrl, rqst, rsp, payload_len)			\
239 	({									\
240 		u8 __data[SSH_COMMAND_MESSAGE_LENGTH(payload_len)];		\
241 		struct ssam_span __buf = { &__data[0], ARRAY_SIZE(__data) };	\
242 										\
243 		ssam_request_sync_with_buffer(ctrl, rqst, rsp, &__buf);		\
244 	})
245 
246 /**
247  * __ssam_retry - Retry request in case of I/O errors or timeouts.
248  * @request: The request function to execute. Must return an integer.
249  * @n:       Number of tries.
250  * @args:    Arguments for the request function.
251  *
252  * Executes the given request function, i.e. calls @request. In case the
253  * request returns %-EREMOTEIO (indicates I/O error) or %-ETIMEDOUT (request
254  * or underlying packet timed out), @request will be re-executed again, up to
255  * @n times in total.
256  *
257  * Return: Returns the return value of the last execution of @request.
258  */
259 #define __ssam_retry(request, n, args...)				\
260 	({								\
261 		int __i, __s = 0;					\
262 									\
263 		for (__i = (n); __i > 0; __i--) {			\
264 			__s = request(args);				\
265 			if (__s != -ETIMEDOUT && __s != -EREMOTEIO)	\
266 				break;					\
267 		}							\
268 		__s;							\
269 	})
270 
271 /**
272  * ssam_retry - Retry request in case of I/O errors or timeouts up to three
273  * times in total.
274  * @request: The request function to execute. Must return an integer.
275  * @args:    Arguments for the request function.
276  *
277  * Executes the given request function, i.e. calls @request. In case the
278  * request returns %-EREMOTEIO (indicates I/O error) or -%ETIMEDOUT (request
279  * or underlying packet timed out), @request will be re-executed again, up to
280  * three times in total.
281  *
282  * See __ssam_retry() for a more generic macro for this purpose.
283  *
284  * Return: Returns the return value of the last execution of @request.
285  */
286 #define ssam_retry(request, args...) \
287 	__ssam_retry(request, 3, args)
288 
289 /**
290  * struct ssam_request_spec - Blue-print specification of SAM request.
291  * @target_category: Category of the request's target. See &enum ssam_ssh_tc.
292  * @target_id:       ID of the request's target.
293  * @command_id:      Command ID of the request.
294  * @instance_id:     Instance ID of the request's target.
295  * @flags:           Flags for the request. See &enum ssam_request_flags.
296  *
297  * Blue-print specification for a SAM request. This struct describes the
298  * unique static parameters of a request (i.e. type) without specifying any of
299  * its instance-specific data (e.g. payload). It is intended to be used as base
300  * for defining simple request functions via the
301  * ``SSAM_DEFINE_SYNC_REQUEST_x()`` family of macros.
302  */
303 struct ssam_request_spec {
304 	u8 target_category;
305 	u8 target_id;
306 	u8 command_id;
307 	u8 instance_id;
308 	u8 flags;
309 };
310 
311 /**
312  * struct ssam_request_spec_md - Blue-print specification for multi-device SAM
313  * request.
314  * @target_category: Category of the request's target. See &enum ssam_ssh_tc.
315  * @command_id:      Command ID of the request.
316  * @flags:           Flags for the request. See &enum ssam_request_flags.
317  *
318  * Blue-print specification for a multi-device SAM request, i.e. a request
319  * that is applicable to multiple device instances, described by their
320  * individual target and instance IDs. This struct describes the unique static
321  * parameters of a request (i.e. type) without specifying any of its
322  * instance-specific data (e.g. payload) and without specifying any of its
323  * device specific IDs (i.e. target and instance ID). It is intended to be
324  * used as base for defining simple multi-device request functions via the
325  * ``SSAM_DEFINE_SYNC_REQUEST_MD_x()`` and ``SSAM_DEFINE_SYNC_REQUEST_CL_x()``
326  * families of macros.
327  */
328 struct ssam_request_spec_md {
329 	u8 target_category;
330 	u8 command_id;
331 	u8 flags;
332 };
333 
334 /**
335  * SSAM_DEFINE_SYNC_REQUEST_N() - Define synchronous SAM request function
336  * with neither argument nor return value.
337  * @name: Name of the generated function.
338  * @spec: Specification (&struct ssam_request_spec) defining the request.
339  *
340  * Defines a function executing the synchronous SAM request specified by
341  * @spec, with the request having neither argument nor return value. The
342  * generated function takes care of setting up the request struct and buffer
343  * allocation, as well as execution of the request itself, returning once the
344  * request has been fully completed. The required transport buffer will be
345  * allocated on the stack.
346  *
347  * The generated function is defined as ``static int name(struct
348  * ssam_controller *ctrl)``, returning the status of the request, which is
349  * zero on success and negative on failure. The ``ctrl`` parameter is the
350  * controller via which the request is being sent.
351  *
352  * Refer to ssam_request_sync_onstack() for more details on the behavior of
353  * the generated function.
354  */
355 #define SSAM_DEFINE_SYNC_REQUEST_N(name, spec...)				\
356 	static int name(struct ssam_controller *ctrl)				\
357 	{									\
358 		struct ssam_request_spec s = (struct ssam_request_spec)spec;	\
359 		struct ssam_request rqst;					\
360 										\
361 		rqst.target_category = s.target_category;			\
362 		rqst.target_id = s.target_id;					\
363 		rqst.command_id = s.command_id;					\
364 		rqst.instance_id = s.instance_id;				\
365 		rqst.flags = s.flags;						\
366 		rqst.length = 0;						\
367 		rqst.payload = NULL;						\
368 										\
369 		return ssam_request_sync_onstack(ctrl, &rqst, NULL, 0);		\
370 	}
371 
372 /**
373  * SSAM_DEFINE_SYNC_REQUEST_W() - Define synchronous SAM request function with
374  * argument.
375  * @name:  Name of the generated function.
376  * @atype: Type of the request's argument.
377  * @spec:  Specification (&struct ssam_request_spec) defining the request.
378  *
379  * Defines a function executing the synchronous SAM request specified by
380  * @spec, with the request taking an argument of type @atype and having no
381  * return value. The generated function takes care of setting up the request
382  * struct, buffer allocation, as well as execution of the request itself,
383  * returning once the request has been fully completed. The required transport
384  * buffer will be allocated on the stack.
385  *
386  * The generated function is defined as ``static int name(struct
387  * ssam_controller *ctrl, const atype *arg)``, returning the status of the
388  * request, which is zero on success and negative on failure. The ``ctrl``
389  * parameter is the controller via which the request is sent. The request
390  * argument is specified via the ``arg`` pointer.
391  *
392  * Refer to ssam_request_sync_onstack() for more details on the behavior of
393  * the generated function.
394  */
395 #define SSAM_DEFINE_SYNC_REQUEST_W(name, atype, spec...)			\
396 	static int name(struct ssam_controller *ctrl, const atype *arg)		\
397 	{									\
398 		struct ssam_request_spec s = (struct ssam_request_spec)spec;	\
399 		struct ssam_request rqst;					\
400 										\
401 		rqst.target_category = s.target_category;			\
402 		rqst.target_id = s.target_id;					\
403 		rqst.command_id = s.command_id;					\
404 		rqst.instance_id = s.instance_id;				\
405 		rqst.flags = s.flags;						\
406 		rqst.length = sizeof(atype);					\
407 		rqst.payload = (u8 *)arg;					\
408 										\
409 		return ssam_request_sync_onstack(ctrl, &rqst, NULL,		\
410 						 sizeof(atype));		\
411 	}
412 
413 /**
414  * SSAM_DEFINE_SYNC_REQUEST_R() - Define synchronous SAM request function with
415  * return value.
416  * @name:  Name of the generated function.
417  * @rtype: Type of the request's return value.
418  * @spec:  Specification (&struct ssam_request_spec) defining the request.
419  *
420  * Defines a function executing the synchronous SAM request specified by
421  * @spec, with the request taking no argument but having a return value of
422  * type @rtype. The generated function takes care of setting up the request
423  * and response structs, buffer allocation, as well as execution of the
424  * request itself, returning once the request has been fully completed. The
425  * required transport buffer will be allocated on the stack.
426  *
427  * The generated function is defined as ``static int name(struct
428  * ssam_controller *ctrl, rtype *ret)``, returning the status of the request,
429  * which is zero on success and negative on failure. The ``ctrl`` parameter is
430  * the controller via which the request is sent. The request's return value is
431  * written to the memory pointed to by the ``ret`` parameter.
432  *
433  * Refer to ssam_request_sync_onstack() for more details on the behavior of
434  * the generated function.
435  */
436 #define SSAM_DEFINE_SYNC_REQUEST_R(name, rtype, spec...)			\
437 	static int name(struct ssam_controller *ctrl, rtype *ret)		\
438 	{									\
439 		struct ssam_request_spec s = (struct ssam_request_spec)spec;	\
440 		struct ssam_request rqst;					\
441 		struct ssam_response rsp;					\
442 		int status;							\
443 										\
444 		rqst.target_category = s.target_category;			\
445 		rqst.target_id = s.target_id;					\
446 		rqst.command_id = s.command_id;					\
447 		rqst.instance_id = s.instance_id;				\
448 		rqst.flags = s.flags | SSAM_REQUEST_HAS_RESPONSE;		\
449 		rqst.length = 0;						\
450 		rqst.payload = NULL;						\
451 										\
452 		rsp.capacity = sizeof(rtype);					\
453 		rsp.length = 0;							\
454 		rsp.pointer = (u8 *)ret;					\
455 										\
456 		status = ssam_request_sync_onstack(ctrl, &rqst, &rsp, 0);	\
457 		if (status)							\
458 			return status;						\
459 										\
460 		if (rsp.length != sizeof(rtype)) {				\
461 			struct device *dev = ssam_controller_device(ctrl);	\
462 			dev_err(dev,						\
463 				"rqst: invalid response length, expected %zu, got %zu (tc: %#04x, cid: %#04x)", \
464 				sizeof(rtype), rsp.length, rqst.target_category,\
465 				rqst.command_id);				\
466 			return -EIO;						\
467 		}								\
468 										\
469 		return 0;							\
470 	}
471 
472 /**
473  * SSAM_DEFINE_SYNC_REQUEST_MD_N() - Define synchronous multi-device SAM
474  * request function with neither argument nor return value.
475  * @name: Name of the generated function.
476  * @spec: Specification (&struct ssam_request_spec_md) defining the request.
477  *
478  * Defines a function executing the synchronous SAM request specified by
479  * @spec, with the request having neither argument nor return value. Device
480  * specifying parameters are not hard-coded, but instead must be provided to
481  * the function. The generated function takes care of setting up the request
482  * struct, buffer allocation, as well as execution of the request itself,
483  * returning once the request has been fully completed. The required transport
484  * buffer will be allocated on the stack.
485  *
486  * The generated function is defined as ``static int name(struct
487  * ssam_controller *ctrl, u8 tid, u8 iid)``, returning the status of the
488  * request, which is zero on success and negative on failure. The ``ctrl``
489  * parameter is the controller via which the request is sent, ``tid`` the
490  * target ID for the request, and ``iid`` the instance ID.
491  *
492  * Refer to ssam_request_sync_onstack() for more details on the behavior of
493  * the generated function.
494  */
495 #define SSAM_DEFINE_SYNC_REQUEST_MD_N(name, spec...)				\
496 	static int name(struct ssam_controller *ctrl, u8 tid, u8 iid)		\
497 	{									\
498 		struct ssam_request_spec_md s = (struct ssam_request_spec_md)spec; \
499 		struct ssam_request rqst;					\
500 										\
501 		rqst.target_category = s.target_category;			\
502 		rqst.target_id = tid;						\
503 		rqst.command_id = s.command_id;					\
504 		rqst.instance_id = iid;						\
505 		rqst.flags = s.flags;						\
506 		rqst.length = 0;						\
507 		rqst.payload = NULL;						\
508 										\
509 		return ssam_request_sync_onstack(ctrl, &rqst, NULL, 0);		\
510 	}
511 
512 /**
513  * SSAM_DEFINE_SYNC_REQUEST_MD_W() - Define synchronous multi-device SAM
514  * request function with argument.
515  * @name:  Name of the generated function.
516  * @atype: Type of the request's argument.
517  * @spec:  Specification (&struct ssam_request_spec_md) defining the request.
518  *
519  * Defines a function executing the synchronous SAM request specified by
520  * @spec, with the request taking an argument of type @atype and having no
521  * return value. Device specifying parameters are not hard-coded, but instead
522  * must be provided to the function. The generated function takes care of
523  * setting up the request struct, buffer allocation, as well as execution of
524  * the request itself, returning once the request has been fully completed.
525  * The required transport buffer will be allocated on the stack.
526  *
527  * The generated function is defined as ``static int name(struct
528  * ssam_controller *ctrl, u8 tid, u8 iid, const atype *arg)``, returning the
529  * status of the request, which is zero on success and negative on failure.
530  * The ``ctrl`` parameter is the controller via which the request is sent,
531  * ``tid`` the target ID for the request, and ``iid`` the instance ID. The
532  * request argument is specified via the ``arg`` pointer.
533  *
534  * Refer to ssam_request_sync_onstack() for more details on the behavior of
535  * the generated function.
536  */
537 #define SSAM_DEFINE_SYNC_REQUEST_MD_W(name, atype, spec...)			\
538 	static int name(struct ssam_controller *ctrl, u8 tid, u8 iid, const atype *arg) \
539 	{									\
540 		struct ssam_request_spec_md s = (struct ssam_request_spec_md)spec; \
541 		struct ssam_request rqst;					\
542 										\
543 		rqst.target_category = s.target_category;			\
544 		rqst.target_id = tid;						\
545 		rqst.command_id = s.command_id;					\
546 		rqst.instance_id = iid;						\
547 		rqst.flags = s.flags;						\
548 		rqst.length = sizeof(atype);					\
549 		rqst.payload = (u8 *)arg;					\
550 										\
551 		return ssam_request_sync_onstack(ctrl, &rqst, NULL,		\
552 						 sizeof(atype));		\
553 	}
554 
555 /**
556  * SSAM_DEFINE_SYNC_REQUEST_MD_R() - Define synchronous multi-device SAM
557  * request function with return value.
558  * @name:  Name of the generated function.
559  * @rtype: Type of the request's return value.
560  * @spec:  Specification (&struct ssam_request_spec_md) defining the request.
561  *
562  * Defines a function executing the synchronous SAM request specified by
563  * @spec, with the request taking no argument but having a return value of
564  * type @rtype. Device specifying parameters are not hard-coded, but instead
565  * must be provided to the function. The generated function takes care of
566  * setting up the request and response structs, buffer allocation, as well as
567  * execution of the request itself, returning once the request has been fully
568  * completed. The required transport buffer will be allocated on the stack.
569  *
570  * The generated function is defined as ``static int name(struct
571  * ssam_controller *ctrl, u8 tid, u8 iid, rtype *ret)``, returning the status
572  * of the request, which is zero on success and negative on failure. The
573  * ``ctrl`` parameter is the controller via which the request is sent, ``tid``
574  * the target ID for the request, and ``iid`` the instance ID. The request's
575  * return value is written to the memory pointed to by the ``ret`` parameter.
576  *
577  * Refer to ssam_request_sync_onstack() for more details on the behavior of
578  * the generated function.
579  */
580 #define SSAM_DEFINE_SYNC_REQUEST_MD_R(name, rtype, spec...)			\
581 	static int name(struct ssam_controller *ctrl, u8 tid, u8 iid, rtype *ret) \
582 	{									\
583 		struct ssam_request_spec_md s = (struct ssam_request_spec_md)spec; \
584 		struct ssam_request rqst;					\
585 		struct ssam_response rsp;					\
586 		int status;							\
587 										\
588 		rqst.target_category = s.target_category;			\
589 		rqst.target_id = tid;						\
590 		rqst.command_id = s.command_id;					\
591 		rqst.instance_id = iid;						\
592 		rqst.flags = s.flags | SSAM_REQUEST_HAS_RESPONSE;		\
593 		rqst.length = 0;						\
594 		rqst.payload = NULL;						\
595 										\
596 		rsp.capacity = sizeof(rtype);					\
597 		rsp.length = 0;							\
598 		rsp.pointer = (u8 *)ret;					\
599 										\
600 		status = ssam_request_sync_onstack(ctrl, &rqst, &rsp, 0);	\
601 		if (status)							\
602 			return status;						\
603 										\
604 		if (rsp.length != sizeof(rtype)) {				\
605 			struct device *dev = ssam_controller_device(ctrl);	\
606 			dev_err(dev,						\
607 				"rqst: invalid response length, expected %zu, got %zu (tc: %#04x, cid: %#04x)", \
608 				sizeof(rtype), rsp.length, rqst.target_category,\
609 				rqst.command_id);				\
610 			return -EIO;						\
611 		}								\
612 										\
613 		return 0;							\
614 	}
615 
616 
617 /* -- Event notifier/callbacks. --------------------------------------------- */
618 
619 #define SSAM_NOTIF_STATE_SHIFT		2
620 #define SSAM_NOTIF_STATE_MASK		((1 << SSAM_NOTIF_STATE_SHIFT) - 1)
621 
622 /**
623  * enum ssam_notif_flags - Flags used in return values from SSAM notifier
624  * callback functions.
625  *
626  * @SSAM_NOTIF_HANDLED:
627  *	Indicates that the notification has been handled. This flag should be
628  *	set by the handler if the handler can act/has acted upon the event
629  *	provided to it. This flag should not be set if the handler is not a
630  *	primary handler intended for the provided event.
631  *
632  *	If this flag has not been set by any handler after the notifier chain
633  *	has been traversed, a warning will be emitted, stating that the event
634  *	has not been handled.
635  *
636  * @SSAM_NOTIF_STOP:
637  *	Indicates that the notifier traversal should stop. If this flag is
638  *	returned from a notifier callback, notifier chain traversal will
639  *	immediately stop and any remaining notifiers will not be called. This
640  *	flag is automatically set when ssam_notifier_from_errno() is called
641  *	with a negative error value.
642  */
643 enum ssam_notif_flags {
644 	SSAM_NOTIF_HANDLED = BIT(0),
645 	SSAM_NOTIF_STOP    = BIT(1),
646 };
647 
648 struct ssam_event_notifier;
649 
650 typedef u32 (*ssam_notifier_fn_t)(struct ssam_event_notifier *nf,
651 				  const struct ssam_event *event);
652 
653 /**
654  * struct ssam_notifier_block - Base notifier block for SSAM event
655  * notifications.
656  * @node:     The node for the list of notifiers.
657  * @fn:       The callback function of this notifier. This function takes the
658  *            respective notifier block and event as input and should return
659  *            a notifier value, which can either be obtained from the flags
660  *            provided in &enum ssam_notif_flags, converted from a standard
661  *            error value via ssam_notifier_from_errno(), or a combination of
662  *            both (e.g. ``ssam_notifier_from_errno(e) | SSAM_NOTIF_HANDLED``).
663  * @priority: Priority value determining the order in which notifier callbacks
664  *            will be called. A higher value means higher priority, i.e. the
665  *            associated callback will be executed earlier than other (lower
666  *            priority) callbacks.
667  */
668 struct ssam_notifier_block {
669 	struct list_head node;
670 	ssam_notifier_fn_t fn;
671 	int priority;
672 };
673 
674 /**
675  * ssam_notifier_from_errno() - Convert standard error value to notifier
676  * return code.
677  * @err: The error code to convert, must be negative (in case of failure) or
678  *       zero (in case of success).
679  *
680  * Return: Returns the notifier return value obtained by converting the
681  * specified @err value. In case @err is negative, the %SSAM_NOTIF_STOP flag
682  * will be set, causing notifier call chain traversal to abort.
683  */
ssam_notifier_from_errno(int err)684 static inline u32 ssam_notifier_from_errno(int err)
685 {
686 	if (WARN_ON(err > 0) || err == 0)
687 		return 0;
688 	else
689 		return ((-err) << SSAM_NOTIF_STATE_SHIFT) | SSAM_NOTIF_STOP;
690 }
691 
692 /**
693  * ssam_notifier_to_errno() - Convert notifier return code to standard error
694  * value.
695  * @ret: The notifier return value to convert.
696  *
697  * Return: Returns the negative error value encoded in @ret or zero if @ret
698  * indicates success.
699  */
ssam_notifier_to_errno(u32 ret)700 static inline int ssam_notifier_to_errno(u32 ret)
701 {
702 	return -(ret >> SSAM_NOTIF_STATE_SHIFT);
703 }
704 
705 
706 /* -- Event/notification registry. ------------------------------------------ */
707 
708 /**
709  * struct ssam_event_registry - Registry specification used for enabling events.
710  * @target_category: Target category for the event registry requests.
711  * @target_id:       Target ID for the event registry requests.
712  * @cid_enable:      Command ID for the event-enable request.
713  * @cid_disable:     Command ID for the event-disable request.
714  *
715  * This struct describes a SAM event registry via the minimal collection of
716  * SAM IDs specifying the requests to use for enabling and disabling an event.
717  * The individual event to be enabled/disabled itself is specified via &struct
718  * ssam_event_id.
719  */
720 struct ssam_event_registry {
721 	u8 target_category;
722 	u8 target_id;
723 	u8 cid_enable;
724 	u8 cid_disable;
725 };
726 
727 /**
728  * struct ssam_event_id - Unique event ID used for enabling events.
729  * @target_category: Target category of the event source.
730  * @instance:        Instance ID of the event source.
731  *
732  * This struct specifies the event to be enabled/disabled via an externally
733  * provided registry. It does not specify the registry to be used itself, this
734  * is done via &struct ssam_event_registry.
735  */
736 struct ssam_event_id {
737 	u8 target_category;
738 	u8 instance;
739 };
740 
741 /**
742  * enum ssam_event_mask - Flags specifying how events are matched to notifiers.
743  *
744  * @SSAM_EVENT_MASK_NONE:
745  *	Run the callback for any event with matching target category. Do not
746  *	do any additional filtering.
747  *
748  * @SSAM_EVENT_MASK_TARGET:
749  *	In addition to filtering by target category, only execute the notifier
750  *	callback for events with a target ID matching to the one of the
751  *	registry used for enabling/disabling the event.
752  *
753  * @SSAM_EVENT_MASK_INSTANCE:
754  *	In addition to filtering by target category, only execute the notifier
755  *	callback for events with an instance ID matching to the instance ID
756  *	used when enabling the event.
757  *
758  * @SSAM_EVENT_MASK_STRICT:
759  *	Do all the filtering above.
760  */
761 enum ssam_event_mask {
762 	SSAM_EVENT_MASK_TARGET   = BIT(0),
763 	SSAM_EVENT_MASK_INSTANCE = BIT(1),
764 
765 	SSAM_EVENT_MASK_NONE = 0,
766 	SSAM_EVENT_MASK_STRICT =
767 		  SSAM_EVENT_MASK_TARGET
768 		| SSAM_EVENT_MASK_INSTANCE,
769 };
770 
771 /**
772  * SSAM_EVENT_REGISTRY() - Define a new event registry.
773  * @tc:      Target category for the event registry requests.
774  * @tid:     Target ID for the event registry requests.
775  * @cid_en:  Command ID for the event-enable request.
776  * @cid_dis: Command ID for the event-disable request.
777  *
778  * Return: Returns the &struct ssam_event_registry specified by the given
779  * parameters.
780  */
781 #define SSAM_EVENT_REGISTRY(tc, tid, cid_en, cid_dis)	\
782 	((struct ssam_event_registry) {			\
783 		.target_category = (tc),		\
784 		.target_id = (tid),			\
785 		.cid_enable = (cid_en),			\
786 		.cid_disable = (cid_dis),		\
787 	})
788 
789 #define SSAM_EVENT_REGISTRY_SAM	\
790 	SSAM_EVENT_REGISTRY(SSAM_SSH_TC_SAM, 0x01, 0x0b, 0x0c)
791 
792 #define SSAM_EVENT_REGISTRY_KIP	\
793 	SSAM_EVENT_REGISTRY(SSAM_SSH_TC_KIP, 0x02, 0x27, 0x28)
794 
795 #define SSAM_EVENT_REGISTRY_REG(tid)\
796 	SSAM_EVENT_REGISTRY(SSAM_SSH_TC_REG, tid, 0x01, 0x02)
797 
798 /**
799  * enum ssam_event_notifier_flags - Flags for event notifiers.
800  * @SSAM_EVENT_NOTIFIER_OBSERVER:
801  *	The corresponding notifier acts as observer. Registering a notifier
802  *	with this flag set will not attempt to enable any event. Equally,
803  *	unregistering will not attempt to disable any event. Note that a
804  *	notifier with this flag may not even correspond to a certain event at
805  *	all, only to a specific event target category. Event matching will not
806  *	be influenced by this flag.
807  */
808 enum ssam_event_notifier_flags {
809 	SSAM_EVENT_NOTIFIER_OBSERVER = BIT(0),
810 };
811 
812 /**
813  * struct ssam_event_notifier - Notifier block for SSAM events.
814  * @base:        The base notifier block with callback function and priority.
815  * @event:       The event for which this block will receive notifications.
816  * @event.reg:   Registry via which the event will be enabled/disabled.
817  * @event.id:    ID specifying the event.
818  * @event.mask:  Flags determining how events are matched to the notifier.
819  * @event.flags: Flags used for enabling the event.
820  * @flags:       Notifier flags (see &enum ssam_event_notifier_flags).
821  */
822 struct ssam_event_notifier {
823 	struct ssam_notifier_block base;
824 
825 	struct {
826 		struct ssam_event_registry reg;
827 		struct ssam_event_id id;
828 		enum ssam_event_mask mask;
829 		u8 flags;
830 	} event;
831 
832 	unsigned long flags;
833 };
834 
835 int ssam_notifier_register(struct ssam_controller *ctrl,
836 			   struct ssam_event_notifier *n);
837 
838 int ssam_notifier_unregister(struct ssam_controller *ctrl,
839 			     struct ssam_event_notifier *n);
840 
841 int ssam_controller_event_enable(struct ssam_controller *ctrl,
842 				 struct ssam_event_registry reg,
843 				 struct ssam_event_id id, u8 flags);
844 
845 int ssam_controller_event_disable(struct ssam_controller *ctrl,
846 				  struct ssam_event_registry reg,
847 				  struct ssam_event_id id, u8 flags);
848 
849 #endif /* _LINUX_SURFACE_AGGREGATOR_CONTROLLER_H */
850