1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * ChromeOS Wilco Embedded Controller
4 *
5 * Copyright 2018 Google LLC
6 */
7
8 #ifndef WILCO_EC_H
9 #define WILCO_EC_H
10
11 #include <linux/device.h>
12 #include <linux/kernel.h>
13
14 /* Message flags for using the mailbox() interface */
15 #define WILCO_EC_FLAG_NO_RESPONSE BIT(0) /* EC does not respond */
16
17 /* Normal commands have a maximum 32 bytes of data */
18 #define EC_MAILBOX_DATA_SIZE 32
19
20 /**
21 * struct wilco_ec_device - Wilco Embedded Controller handle.
22 * @dev: Device handle.
23 * @mailbox_lock: Mutex to ensure one mailbox command at a time.
24 * @io_command: I/O port for mailbox command. Provided by ACPI.
25 * @io_data: I/O port for mailbox data. Provided by ACPI.
26 * @io_packet: I/O port for mailbox packet data. Provided by ACPI.
27 * @data_buffer: Buffer used for EC communication. The same buffer
28 * is used to hold the request and the response.
29 * @data_size: Size of the data buffer used for EC communication.
30 * @debugfs_pdev: The child platform_device used by the debugfs sub-driver.
31 * @rtc_pdev: The child platform_device used by the RTC sub-driver.
32 * @telem_pdev: The child platform_device used by the telemetry sub-driver.
33 */
34 struct wilco_ec_device {
35 struct device *dev;
36 struct mutex mailbox_lock;
37 struct resource *io_command;
38 struct resource *io_data;
39 struct resource *io_packet;
40 void *data_buffer;
41 size_t data_size;
42 struct platform_device *debugfs_pdev;
43 struct platform_device *rtc_pdev;
44 struct platform_device *telem_pdev;
45 };
46
47 /**
48 * struct wilco_ec_request - Mailbox request message format.
49 * @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
50 * @checksum: Sum of all bytes must be 0.
51 * @mailbox_id: Mailbox identifier, specifies the command set.
52 * @mailbox_version: Mailbox interface version %EC_MAILBOX_VERSION
53 * @reserved: Set to zero.
54 * @data_size: Length of following data.
55 */
56 struct wilco_ec_request {
57 u8 struct_version;
58 u8 checksum;
59 u16 mailbox_id;
60 u8 mailbox_version;
61 u8 reserved;
62 u16 data_size;
63 } __packed;
64
65 /**
66 * struct wilco_ec_response - Mailbox response message format.
67 * @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
68 * @checksum: Sum of all bytes must be 0.
69 * @result: Result code from the EC. Non-zero indicates an error.
70 * @data_size: Length of the response data buffer.
71 * @reserved: Set to zero.
72 * @data: Response data buffer. Max size is %EC_MAILBOX_DATA_SIZE_EXTENDED.
73 */
74 struct wilco_ec_response {
75 u8 struct_version;
76 u8 checksum;
77 u16 result;
78 u16 data_size;
79 u8 reserved[2];
80 u8 data[0];
81 } __packed;
82
83 /**
84 * enum wilco_ec_msg_type - Message type to select a set of command codes.
85 * @WILCO_EC_MSG_LEGACY: Legacy EC messages for standard EC behavior.
86 * @WILCO_EC_MSG_PROPERTY: Get/Set/Sync EC controlled NVRAM property.
87 * @WILCO_EC_MSG_TELEMETRY: Request telemetry data from the EC.
88 */
89 enum wilco_ec_msg_type {
90 WILCO_EC_MSG_LEGACY = 0x00f0,
91 WILCO_EC_MSG_PROPERTY = 0x00f2,
92 WILCO_EC_MSG_TELEMETRY = 0x00f5,
93 };
94
95 /**
96 * struct wilco_ec_message - Request and response message.
97 * @type: Mailbox message type.
98 * @flags: Message flags, e.g. %WILCO_EC_FLAG_NO_RESPONSE.
99 * @request_size: Number of bytes to send to the EC.
100 * @request_data: Buffer containing the request data.
101 * @response_size: Number of bytes to read from EC.
102 * @response_data: Buffer containing the response data, should be
103 * response_size bytes and allocated by caller.
104 */
105 struct wilco_ec_message {
106 enum wilco_ec_msg_type type;
107 u8 flags;
108 size_t request_size;
109 void *request_data;
110 size_t response_size;
111 void *response_data;
112 };
113
114 /**
115 * wilco_ec_mailbox() - Send request to the EC and receive the response.
116 * @ec: Wilco EC device.
117 * @msg: Wilco EC message.
118 *
119 * Return: Number of bytes received or negative error code on failure.
120 */
121 int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg);
122
123 /*
124 * A Property is typically a data item that is stored to NVRAM
125 * by the EC. Each of these data items has an index associated
126 * with it, known as the Property ID (PID). Properties may have
127 * variable lengths, up to a max of WILCO_EC_PROPERTY_MAX_SIZE
128 * bytes. Properties can be simple integers, or they may be more
129 * complex binary data.
130 */
131
132 #define WILCO_EC_PROPERTY_MAX_SIZE 4
133
134 /**
135 * struct ec_property_set_msg - Message to get or set a property.
136 * @property_id: Which property to get or set.
137 * @length: Number of bytes of |data| that are used.
138 * @data: Actual property data.
139 */
140 struct wilco_ec_property_msg {
141 u32 property_id;
142 int length;
143 u8 data[WILCO_EC_PROPERTY_MAX_SIZE];
144 };
145
146 /**
147 * wilco_ec_get_property() - Retrieve a property from the EC.
148 * @ec: Embedded Controller device.
149 * @prop_msg: Message for request and response.
150 *
151 * The property_id field of |prop_msg| should be filled before calling this
152 * function. The result will be stored in the data and length fields.
153 *
154 * Return: 0 on success, negative error code on failure.
155 */
156 int wilco_ec_get_property(struct wilco_ec_device *ec,
157 struct wilco_ec_property_msg *prop_msg);
158
159 /**
160 * wilco_ec_set_property() - Store a property on the EC.
161 * @ec: Embedded Controller device.
162 * @prop_msg: Message for request and response.
163 *
164 * The property_id, length, and data fields of |prop_msg| should be
165 * filled before calling this function.
166 *
167 * Return: 0 on success, negative error code on failure.
168 */
169 int wilco_ec_set_property(struct wilco_ec_device *ec,
170 struct wilco_ec_property_msg *prop_msg);
171
172 /**
173 * wilco_ec_get_byte_property() - Retrieve a byte-size property from the EC.
174 * @ec: Embedded Controller device.
175 * @property_id: Which property to retrieve.
176 * @val: The result value, will be filled by this function.
177 *
178 * Return: 0 on success, negative error code on failure.
179 */
180 int wilco_ec_get_byte_property(struct wilco_ec_device *ec, u32 property_id,
181 u8 *val);
182
183 /**
184 * wilco_ec_get_byte_property() - Store a byte-size property on the EC.
185 * @ec: Embedded Controller device.
186 * @property_id: Which property to store.
187 * @val: Value to store.
188 *
189 * Return: 0 on success, negative error code on failure.
190 */
191 int wilco_ec_set_byte_property(struct wilco_ec_device *ec, u32 property_id,
192 u8 val);
193
194 /**
195 * wilco_ec_add_sysfs() - Create sysfs entries
196 * @ec: Wilco EC device
197 *
198 * wilco_ec_remove_sysfs() needs to be called afterwards
199 * to perform the necessary cleanup.
200 *
201 * Return: 0 on success or negative error code on failure.
202 */
203 int wilco_ec_add_sysfs(struct wilco_ec_device *ec);
204 void wilco_ec_remove_sysfs(struct wilco_ec_device *ec);
205
206 #endif /* WILCO_EC_H */