1/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
2/*
3 * Surface System Aggregator Module (SSAM) user-space EC interface.
4 *
5 * Definitions, structs, and IOCTLs for the /dev/surface/aggregator misc
6 * device. This device provides direct user-space access to the SSAM EC.
7 * Intended for debugging and development.
8 *
9 * Copyright (C) 2020-2021 Maximilian Luz <luzmaximilian@gmail.com>
10 */
11
12#ifndef _UAPI_LINUX_SURFACE_AGGREGATOR_CDEV_H
13#define _UAPI_LINUX_SURFACE_AGGREGATOR_CDEV_H
14
15#include <linux/ioctl.h>
16#include <linux/types.h>
17
18/**
19 * enum ssam_cdev_request_flags - Request flags for SSAM cdev request IOCTL.
20 *
21 * @SSAM_CDEV_REQUEST_HAS_RESPONSE:
22 *	Specifies that the request expects a response. If not set, the request
23 *	will be directly completed after its underlying packet has been
24 *	transmitted. If set, the request transport system waits for a response
25 *	of the request.
26 *
27 * @SSAM_CDEV_REQUEST_UNSEQUENCED:
28 *	Specifies that the request should be transmitted via an unsequenced
29 *	packet. If set, the request must not have a response, meaning that this
30 *	flag and the %SSAM_CDEV_REQUEST_HAS_RESPONSE flag are mutually
31 *	exclusive.
32 */
33enum ssam_cdev_request_flags {
34	SSAM_CDEV_REQUEST_HAS_RESPONSE = 0x01,
35	SSAM_CDEV_REQUEST_UNSEQUENCED  = 0x02,
36};
37
38/**
39 * struct ssam_cdev_request - Controller request IOCTL argument.
40 * @target_category: Target category of the SAM request.
41 * @target_id:       Target ID of the SAM request.
42 * @command_id:      Command ID of the SAM request.
43 * @instance_id:     Instance ID of the SAM request.
44 * @flags:           Request flags (see &enum ssam_cdev_request_flags).
45 * @status:          Request status (output).
46 * @payload:         Request payload (input data).
47 * @payload.data:    Pointer to request payload data.
48 * @payload.length:  Length of request payload data (in bytes).
49 * @response:        Request response (output data).
50 * @response.data:   Pointer to response buffer.
51 * @response.length: On input: Capacity of response buffer (in bytes).
52 *                   On output: Length of request response (number of bytes
53 *                   in the buffer that are actually used).
54 */
55struct ssam_cdev_request {
56	__u8 target_category;
57	__u8 target_id;
58	__u8 command_id;
59	__u8 instance_id;
60	__u16 flags;
61	__s16 status;
62
63	struct {
64		__u64 data;
65		__u16 length;
66		__u8 __pad[6];
67	} payload;
68
69	struct {
70		__u64 data;
71		__u16 length;
72		__u8 __pad[6];
73	} response;
74} __attribute__((__packed__));
75
76/**
77 * struct ssam_cdev_notifier_desc - Notifier descriptor.
78 * @priority:        Priority value determining the order in which notifier
79 *                   callbacks will be called. A higher value means higher
80 *                   priority, i.e. the associated callback will be executed
81 *                   earlier than other (lower priority) callbacks.
82 * @target_category: The event target category for which this notifier should
83 *                   receive events.
84 *
85 * Specifies the notifier that should be registered or unregistered,
86 * specifically with which priority and for which target category of events.
87 */
88struct ssam_cdev_notifier_desc {
89	__s32 priority;
90	__u8 target_category;
91} __attribute__((__packed__));
92
93/**
94 * struct ssam_cdev_event_desc - Event descriptor.
95 * @reg:                 Registry via which the event will be enabled/disabled.
96 * @reg.target_category: Target category for the event registry requests.
97 * @reg.target_id:       Target ID for the event registry requests.
98 * @reg.cid_enable:      Command ID for the event-enable request.
99 * @reg.cid_disable:     Command ID for the event-disable request.
100 * @id:                  ID specifying the event.
101 * @id.target_category:  Target category of the event source.
102 * @id.instance:         Instance ID of the event source.
103 * @flags:               Flags used for enabling the event.
104 *
105 * Specifies which event should be enabled/disabled and how to do that.
106 */
107struct ssam_cdev_event_desc {
108	struct {
109		__u8 target_category;
110		__u8 target_id;
111		__u8 cid_enable;
112		__u8 cid_disable;
113	} reg;
114
115	struct {
116		__u8 target_category;
117		__u8 instance;
118	} id;
119
120	__u8 flags;
121} __attribute__((__packed__));
122
123/**
124 * struct ssam_cdev_event - SSAM event sent by the EC.
125 * @target_category: Target category of the event source. See &enum ssam_ssh_tc.
126 * @target_id:       Target ID of the event source.
127 * @command_id:      Command ID of the event.
128 * @instance_id:     Instance ID of the event source.
129 * @length:          Length of the event payload in bytes.
130 * @data:            Event payload data.
131 */
132struct ssam_cdev_event {
133	__u8 target_category;
134	__u8 target_id;
135	__u8 command_id;
136	__u8 instance_id;
137	__u16 length;
138	__u8 data[];
139} __attribute__((__packed__));
140
141#define SSAM_CDEV_REQUEST		_IOWR(0xA5, 1, struct ssam_cdev_request)
142#define SSAM_CDEV_NOTIF_REGISTER	_IOW(0xA5, 2, struct ssam_cdev_notifier_desc)
143#define SSAM_CDEV_NOTIF_UNREGISTER	_IOW(0xA5, 3, struct ssam_cdev_notifier_desc)
144#define SSAM_CDEV_EVENT_ENABLE		_IOW(0xA5, 4, struct ssam_cdev_event_desc)
145#define SSAM_CDEV_EVENT_DISABLE		_IOW(0xA5, 5, struct ssam_cdev_event_desc)
146
147#endif /* _UAPI_LINUX_SURFACE_AGGREGATOR_CDEV_H */
148