1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * ChromeOS Embedded Controller protocol interface.
4 *
5 * Copyright (C) 2012 Google, Inc
6 */
7
8 #ifndef __LINUX_CROS_EC_PROTO_H
9 #define __LINUX_CROS_EC_PROTO_H
10
11 #include <linux/device.h>
12 #include <linux/mutex.h>
13 #include <linux/notifier.h>
14
15 #include <linux/platform_data/cros_ec_commands.h>
16
17 #define CROS_EC_DEV_NAME "cros_ec"
18 #define CROS_EC_DEV_FP_NAME "cros_fp"
19 #define CROS_EC_DEV_ISH_NAME "cros_ish"
20 #define CROS_EC_DEV_PD_NAME "cros_pd"
21 #define CROS_EC_DEV_SCP_NAME "cros_scp"
22 #define CROS_EC_DEV_TP_NAME "cros_tp"
23
24 /*
25 * The EC is unresponsive for a time after a reboot command. Add a
26 * simple delay to make sure that the bus stays locked.
27 */
28 #define EC_REBOOT_DELAY_MS 50
29
30 /*
31 * Max bus-specific overhead incurred by request/responses.
32 * I2C requires 1 additional byte for requests.
33 * I2C requires 2 additional bytes for responses.
34 * SPI requires up to 32 additional bytes for responses.
35 */
36 #define EC_PROTO_VERSION_UNKNOWN 0
37 #define EC_MAX_REQUEST_OVERHEAD 1
38 #define EC_MAX_RESPONSE_OVERHEAD 32
39
40 /*
41 * Command interface between EC and AP, for LPC, I2C and SPI interfaces.
42 */
43 enum {
44 EC_MSG_TX_HEADER_BYTES = 3,
45 EC_MSG_TX_TRAILER_BYTES = 1,
46 EC_MSG_TX_PROTO_BYTES = EC_MSG_TX_HEADER_BYTES +
47 EC_MSG_TX_TRAILER_BYTES,
48 EC_MSG_RX_PROTO_BYTES = 3,
49
50 /* Max length of messages for proto 2*/
51 EC_PROTO2_MSG_BYTES = EC_PROTO2_MAX_PARAM_SIZE +
52 EC_MSG_TX_PROTO_BYTES,
53
54 EC_MAX_MSG_BYTES = 64 * 1024,
55 };
56
57 /**
58 * struct cros_ec_command - Information about a ChromeOS EC command.
59 * @version: Command version number (often 0).
60 * @command: Command to send (EC_CMD_...).
61 * @outsize: Outgoing length in bytes.
62 * @insize: Max number of bytes to accept from the EC.
63 * @result: EC's response to the command (separate from communication failure).
64 * @data: Where to put the incoming data from EC and outgoing data to EC.
65 */
66 struct cros_ec_command {
67 uint32_t version;
68 uint32_t command;
69 uint32_t outsize;
70 uint32_t insize;
71 uint32_t result;
72 uint8_t data[0];
73 };
74
75 /**
76 * struct cros_ec_device - Information about a ChromeOS EC device.
77 * @phys_name: Name of physical comms layer (e.g. 'i2c-4').
78 * @dev: Device pointer for physical comms device
79 * @was_wake_device: True if this device was set to wake the system from
80 * sleep at the last suspend.
81 * @cros_class: The class structure for this device.
82 * @cmd_readmem: Direct read of the EC memory-mapped region, if supported.
83 * @offset: Is within EC_LPC_ADDR_MEMMAP region.
84 * @bytes: Number of bytes to read. zero means "read a string" (including
85 * the trailing '\0'). At most only EC_MEMMAP_SIZE bytes can be
86 * read. Caller must ensure that the buffer is large enough for the
87 * result when reading a string.
88 * @max_request: Max size of message requested.
89 * @max_response: Max size of message response.
90 * @max_passthru: Max sice of passthru message.
91 * @proto_version: The protocol version used for this device.
92 * @priv: Private data.
93 * @irq: Interrupt to use.
94 * @id: Device id.
95 * @din: Input buffer (for data from EC). This buffer will always be
96 * dword-aligned and include enough space for up to 7 word-alignment
97 * bytes also, so we can ensure that the body of the message is always
98 * dword-aligned (64-bit). We use this alignment to keep ARM and x86
99 * happy. Probably word alignment would be OK, there might be a small
100 * performance advantage to using dword.
101 * @dout: Output buffer (for data to EC). This buffer will always be
102 * dword-aligned and include enough space for up to 7 word-alignment
103 * bytes also, so we can ensure that the body of the message is always
104 * dword-aligned (64-bit). We use this alignment to keep ARM and x86
105 * happy. Probably word alignment would be OK, there might be a small
106 * performance advantage to using dword.
107 * @din_size: Size of din buffer to allocate (zero to use static din).
108 * @dout_size: Size of dout buffer to allocate (zero to use static dout).
109 * @wake_enabled: True if this device can wake the system from sleep.
110 * @suspended: True if this device had been suspended.
111 * @cmd_xfer: Send command to EC and get response.
112 * Returns the number of bytes received if the communication
113 * succeeded, but that doesn't mean the EC was happy with the
114 * command. The caller should check msg.result for the EC's result
115 * code.
116 * @pkt_xfer: Send packet to EC and get response.
117 * @lock: One transaction at a time.
118 * @mkbp_event_supported: True if this EC supports the MKBP event protocol.
119 * @host_sleep_v1: True if this EC supports the sleep v1 command.
120 * @event_notifier: Interrupt event notifier for transport devices.
121 * @event_data: Raw payload transferred with the MKBP event.
122 * @event_size: Size in bytes of the event data.
123 * @host_event_wake_mask: Mask of host events that cause wake from suspend.
124 * @ec: The platform_device used by the mfd driver to interface with the
125 * main EC.
126 * @pd: The platform_device used by the mfd driver to interface with the
127 * PD behind an EC.
128 */
129 struct cros_ec_device {
130 /* These are used by other drivers that want to talk to the EC */
131 const char *phys_name;
132 struct device *dev;
133 bool was_wake_device;
134 struct class *cros_class;
135 int (*cmd_readmem)(struct cros_ec_device *ec, unsigned int offset,
136 unsigned int bytes, void *dest);
137
138 /* These are used to implement the platform-specific interface */
139 u16 max_request;
140 u16 max_response;
141 u16 max_passthru;
142 u16 proto_version;
143 void *priv;
144 int irq;
145 u8 *din;
146 u8 *dout;
147 int din_size;
148 int dout_size;
149 bool wake_enabled;
150 bool suspended;
151 int (*cmd_xfer)(struct cros_ec_device *ec,
152 struct cros_ec_command *msg);
153 int (*pkt_xfer)(struct cros_ec_device *ec,
154 struct cros_ec_command *msg);
155 struct mutex lock;
156 bool mkbp_event_supported;
157 bool host_sleep_v1;
158 struct blocking_notifier_head event_notifier;
159
160 struct ec_response_get_next_event_v1 event_data;
161 int event_size;
162 u32 host_event_wake_mask;
163 u32 last_resume_result;
164
165 /* The platform devices used by the mfd driver */
166 struct platform_device *ec;
167 struct platform_device *pd;
168 };
169
170 /**
171 * struct cros_ec_sensor_platform - ChromeOS EC sensor platform information.
172 * @sensor_num: Id of the sensor, as reported by the EC.
173 */
174 struct cros_ec_sensor_platform {
175 u8 sensor_num;
176 };
177
178 /**
179 * struct cros_ec_platform - ChromeOS EC platform information.
180 * @ec_name: Name of EC device (e.g. 'cros-ec', 'cros-pd', ...)
181 * used in /dev/ and sysfs.
182 * @cmd_offset: Offset to apply for each command. Set when
183 * registering a device behind another one.
184 */
185 struct cros_ec_platform {
186 const char *ec_name;
187 u16 cmd_offset;
188 };
189
190 /**
191 * cros_ec_suspend() - Handle a suspend operation for the ChromeOS EC device.
192 * @ec_dev: Device to suspend.
193 *
194 * This can be called by drivers to handle a suspend event.
195 *
196 * Return: 0 on success or negative error code.
197 */
198 int cros_ec_suspend(struct cros_ec_device *ec_dev);
199
200 /**
201 * cros_ec_resume() - Handle a resume operation for the ChromeOS EC device.
202 * @ec_dev: Device to resume.
203 *
204 * This can be called by drivers to handle a resume event.
205 *
206 * Return: 0 on success or negative error code.
207 */
208 int cros_ec_resume(struct cros_ec_device *ec_dev);
209
210 /**
211 * cros_ec_prepare_tx() - Prepare an outgoing message in the output buffer.
212 * @ec_dev: Device to register.
213 * @msg: Message to write.
214 *
215 * This is intended to be used by all ChromeOS EC drivers, but at present
216 * only SPI uses it. Once LPC uses the same protocol it can start using it.
217 * I2C could use it now, with a refactor of the existing code.
218 *
219 * Return: 0 on success or negative error code.
220 */
221 int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
222 struct cros_ec_command *msg);
223
224 /**
225 * cros_ec_check_result() - Check ec_msg->result.
226 * @ec_dev: EC device.
227 * @msg: Message to check.
228 *
229 * This is used by ChromeOS EC drivers to check the ec_msg->result for
230 * errors and to warn about them.
231 *
232 * Return: 0 on success or negative error code.
233 */
234 int cros_ec_check_result(struct cros_ec_device *ec_dev,
235 struct cros_ec_command *msg);
236
237 /**
238 * cros_ec_cmd_xfer() - Send a command to the ChromeOS EC.
239 * @ec_dev: EC device.
240 * @msg: Message to write.
241 *
242 * Call this to send a command to the ChromeOS EC. This should be used
243 * instead of calling the EC's cmd_xfer() callback directly.
244 *
245 * Return: 0 on success or negative error code.
246 */
247 int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
248 struct cros_ec_command *msg);
249
250 /**
251 * cros_ec_cmd_xfer_status() - Send a command to the ChromeOS EC.
252 * @ec_dev: EC device.
253 * @msg: Message to write.
254 *
255 * This function is identical to cros_ec_cmd_xfer, except it returns success
256 * status only if both the command was transmitted successfully and the EC
257 * replied with success status. It's not necessary to check msg->result when
258 * using this function.
259 *
260 * Return: The number of bytes transferred on success or negative error code.
261 */
262 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
263 struct cros_ec_command *msg);
264
265 /**
266 * cros_ec_register() - Register a new ChromeOS EC, using the provided info.
267 * @ec_dev: Device to register.
268 *
269 * Before calling this, allocate a pointer to a new device and then fill
270 * in all the fields up to the --private-- marker.
271 *
272 * Return: 0 on success or negative error code.
273 */
274 int cros_ec_register(struct cros_ec_device *ec_dev);
275
276 /**
277 * cros_ec_unregister() - Remove a ChromeOS EC.
278 * @ec_dev: Device to unregister.
279 *
280 * Call this to deregister a ChromeOS EC, then clean up any private data.
281 *
282 * Return: 0 on success or negative error code.
283 */
284 int cros_ec_unregister(struct cros_ec_device *ec_dev);
285
286 /**
287 * cros_ec_query_all() - Query the protocol version supported by the
288 * ChromeOS EC.
289 * @ec_dev: Device to register.
290 *
291 * Return: 0 on success or negative error code.
292 */
293 int cros_ec_query_all(struct cros_ec_device *ec_dev);
294
295 /**
296 * cros_ec_get_next_event() - Fetch next event from the ChromeOS EC.
297 * @ec_dev: Device to fetch event from.
298 * @wake_event: Pointer to a bool set to true upon return if the event might be
299 * treated as a wake event. Ignored if null.
300 *
301 * Return: negative error code on errors; 0 for no data; or else number of
302 * bytes received (i.e., an event was retrieved successfully). Event types are
303 * written out to @ec_dev->event_data.event_type on success.
304 */
305 int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event);
306
307 /**
308 * cros_ec_get_host_event() - Return a mask of event set by the ChromeOS EC.
309 * @ec_dev: Device to fetch event from.
310 *
311 * When MKBP is supported, when the EC raises an interrupt, we collect the
312 * events raised and call the functions in the ec notifier. This function
313 * is a helper to know which events are raised.
314 *
315 * Return: 0 on error or non-zero bitmask of one or more EC_HOST_EVENT_*.
316 */
317 u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
318
319 #endif /* __LINUX_CROS_EC_PROTO_H */