tjh.dev
Linux kernel mirror (for testing)
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linux
1/*
2 * ChromeOS EC multi-function device
3 *
4 * Copyright (C) 2012 Google, Inc
5 *
6 * This software is licensed under the terms of the GNU General Public
7 * License version 2, as published by the Free Software Foundation, and
8 * may be copied, distributed, and modified under those terms.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 */
15
16#ifndef __LINUX_MFD_CROS_EC_H
17#define __LINUX_MFD_CROS_EC_H
18
19#include <linux/cdev.h>
20#include <linux/device.h>
21#include <linux/notifier.h>
22#include <linux/mfd/cros_ec_commands.h>
23#include <linux/mutex.h>
24
25#define CROS_EC_DEV_NAME "cros_ec"
26#define CROS_EC_DEV_PD_NAME "cros_pd"
27
28/*
29 * The EC is unresponsive for a time after a reboot command. Add a
30 * simple delay to make sure that the bus stays locked.
31 */
32#define EC_REBOOT_DELAY_MS 50
33
34/*
35 * Max bus-specific overhead incurred by request/responses.
36 * I2C requires 1 additional byte for requests.
37 * I2C requires 2 additional bytes for responses.
38 * */
39#define EC_PROTO_VERSION_UNKNOWN 0
40#define EC_MAX_REQUEST_OVERHEAD 1
41#define EC_MAX_RESPONSE_OVERHEAD 2
42
43/*
44 * Command interface between EC and AP, for LPC, I2C and SPI interfaces.
45 */
46enum {
47 EC_MSG_TX_HEADER_BYTES = 3,
48 EC_MSG_TX_TRAILER_BYTES = 1,
49 EC_MSG_TX_PROTO_BYTES = EC_MSG_TX_HEADER_BYTES +
50 EC_MSG_TX_TRAILER_BYTES,
51 EC_MSG_RX_PROTO_BYTES = 3,
52
53 /* Max length of messages for proto 2*/
54 EC_PROTO2_MSG_BYTES = EC_PROTO2_MAX_PARAM_SIZE +
55 EC_MSG_TX_PROTO_BYTES,
56
57 EC_MAX_MSG_BYTES = 64 * 1024,
58};
59
60/*
61 * @version: Command version number (often 0)
62 * @command: Command to send (EC_CMD_...)
63 * @outsize: Outgoing length in bytes
64 * @insize: Max number of bytes to accept from EC
65 * @result: EC's response to the command (separate from communication failure)
66 * @data: Where to put the incoming data from EC and outgoing data to EC
67 */
68struct cros_ec_command {
69 uint32_t version;
70 uint32_t command;
71 uint32_t outsize;
72 uint32_t insize;
73 uint32_t result;
74 uint8_t data[0];
75};
76
77/**
78 * struct cros_ec_device - Information about a ChromeOS EC device
79 *
80 * @phys_name: name of physical comms layer (e.g. 'i2c-4')
81 * @dev: Device pointer for physical comms device
82 * @was_wake_device: true if this device was set to wake the system from
83 * sleep at the last suspend
84 * @cmd_readmem: direct read of the EC memory-mapped region, if supported
85 * @offset is within EC_LPC_ADDR_MEMMAP region.
86 * @bytes: number of bytes to read. zero means "read a string" (including
87 * the trailing '\0'). At most only EC_MEMMAP_SIZE bytes can be read.
88 * Caller must ensure that the buffer is large enough for the result when
89 * reading a string.
90 *
91 * @priv: Private data
92 * @irq: Interrupt to use
93 * @id: Device id
94 * @din: input buffer (for data from EC)
95 * @dout: output buffer (for data to EC)
96 * \note
97 * These two buffers will always be dword-aligned and include enough
98 * space for up to 7 word-alignment bytes also, so we can ensure that
99 * the body of the message is always dword-aligned (64-bit).
100 * We use this alignment to keep ARM and x86 happy. Probably word
101 * alignment would be OK, there might be a small performance advantage
102 * to using dword.
103 * @din_size: size of din buffer to allocate (zero to use static din)
104 * @dout_size: size of dout buffer to allocate (zero to use static dout)
105 * @wake_enabled: true if this device can wake the system from sleep
106 * @cmd_xfer: send command to EC and get response
107 * Returns the number of bytes received if the communication succeeded, but
108 * that doesn't mean the EC was happy with the command. The caller
109 * should check msg.result for the EC's result code.
110 * @pkt_xfer: send packet to EC and get response
111 * @lock: one transaction at a time
112 * @mkbp_event_supported: true if this EC supports the MKBP event protocol.
113 * @event_notifier: interrupt event notifier for transport devices.
114 * @event_data: raw payload transferred with the MKBP event.
115 * @event_size: size in bytes of the event data.
116 */
117struct cros_ec_device {
118
119 /* These are used by other drivers that want to talk to the EC */
120 const char *phys_name;
121 struct device *dev;
122 bool was_wake_device;
123 struct class *cros_class;
124 int (*cmd_readmem)(struct cros_ec_device *ec, unsigned int offset,
125 unsigned int bytes, void *dest);
126
127 /* These are used to implement the platform-specific interface */
128 u16 max_request;
129 u16 max_response;
130 u16 max_passthru;
131 u16 proto_version;
132 void *priv;
133 int irq;
134 u8 *din;
135 u8 *dout;
136 int din_size;
137 int dout_size;
138 bool wake_enabled;
139 int (*cmd_xfer)(struct cros_ec_device *ec,
140 struct cros_ec_command *msg);
141 int (*pkt_xfer)(struct cros_ec_device *ec,
142 struct cros_ec_command *msg);
143 struct mutex lock;
144 bool mkbp_event_supported;
145 struct blocking_notifier_head event_notifier;
146
147 struct ec_response_get_next_event event_data;
148 int event_size;
149};
150
151/* struct cros_ec_platform - ChromeOS EC platform information
152 *
153 * @ec_name: name of EC device (e.g. 'cros-ec', 'cros-pd', ...)
154 * used in /dev/ and sysfs.
155 * @cmd_offset: offset to apply for each command. Set when
156 * registering a devicde behind another one.
157 */
158struct cros_ec_platform {
159 const char *ec_name;
160 u16 cmd_offset;
161};
162
163/*
164 * struct cros_ec_dev - ChromeOS EC device entry point
165 *
166 * @class_dev: Device structure used in sysfs
167 * @cdev: Character device structure in /dev
168 * @ec_dev: cros_ec_device structure to talk to the physical device
169 * @dev: pointer to the platform device
170 * @cmd_offset: offset to apply for each command.
171 */
172struct cros_ec_dev {
173 struct device class_dev;
174 struct cdev cdev;
175 struct cros_ec_device *ec_dev;
176 struct device *dev;
177 u16 cmd_offset;
178};
179
180/**
181 * cros_ec_suspend - Handle a suspend operation for the ChromeOS EC device
182 *
183 * This can be called by drivers to handle a suspend event.
184 *
185 * ec_dev: Device to suspend
186 * @return 0 if ok, -ve on error
187 */
188int cros_ec_suspend(struct cros_ec_device *ec_dev);
189
190/**
191 * cros_ec_resume - Handle a resume operation for the ChromeOS EC device
192 *
193 * This can be called by drivers to handle a resume event.
194 *
195 * @ec_dev: Device to resume
196 * @return 0 if ok, -ve on error
197 */
198int cros_ec_resume(struct cros_ec_device *ec_dev);
199
200/**
201 * cros_ec_prepare_tx - Prepare an outgoing message in the output buffer
202 *
203 * This is intended to be used by all ChromeOS EC drivers, but at present
204 * only SPI uses it. Once LPC uses the same protocol it can start using it.
205 * I2C could use it now, with a refactor of the existing code.
206 *
207 * @ec_dev: Device to register
208 * @msg: Message to write
209 */
210int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
211 struct cros_ec_command *msg);
212
213/**
214 * cros_ec_check_result - Check ec_msg->result
215 *
216 * This is used by ChromeOS EC drivers to check the ec_msg->result for
217 * errors and to warn about them.
218 *
219 * @ec_dev: EC device
220 * @msg: Message to check
221 */
222int cros_ec_check_result(struct cros_ec_device *ec_dev,
223 struct cros_ec_command *msg);
224
225/**
226 * cros_ec_cmd_xfer - Send a command to the ChromeOS EC
227 *
228 * Call this to send a command to the ChromeOS EC. This should be used
229 * instead of calling the EC's cmd_xfer() callback directly.
230 *
231 * @ec_dev: EC device
232 * @msg: Message to write
233 */
234int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
235 struct cros_ec_command *msg);
236
237/**
238 * cros_ec_cmd_xfer_status - Send a command to the ChromeOS EC
239 *
240 * This function is identical to cros_ec_cmd_xfer, except it returns success
241 * status only if both the command was transmitted successfully and the EC
242 * replied with success status. It's not necessary to check msg->result when
243 * using this function.
244 *
245 * @ec_dev: EC device
246 * @msg: Message to write
247 * @return: Num. of bytes transferred on success, <0 on failure
248 */
249int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
250 struct cros_ec_command *msg);
251
252/**
253 * cros_ec_remove - Remove a ChromeOS EC
254 *
255 * Call this to deregister a ChromeOS EC, then clean up any private data.
256 *
257 * @ec_dev: Device to register
258 * @return 0 if ok, -ve on error
259 */
260int cros_ec_remove(struct cros_ec_device *ec_dev);
261
262/**
263 * cros_ec_register - Register a new ChromeOS EC, using the provided info
264 *
265 * Before calling this, allocate a pointer to a new device and then fill
266 * in all the fields up to the --private-- marker.
267 *
268 * @ec_dev: Device to register
269 * @return 0 if ok, -ve on error
270 */
271int cros_ec_register(struct cros_ec_device *ec_dev);
272
273/**
274 * cros_ec_query_all - Query the protocol version supported by the ChromeOS EC
275 *
276 * @ec_dev: Device to register
277 * @return 0 if ok, -ve on error
278 */
279int cros_ec_query_all(struct cros_ec_device *ec_dev);
280
281/**
282 * cros_ec_get_next_event - Fetch next event from the ChromeOS EC
283 *
284 * @ec_dev: Device to fetch event from
285 *
286 * Returns: 0 on success, Linux error number on failure
287 */
288int cros_ec_get_next_event(struct cros_ec_device *ec_dev);
289
290/* sysfs stuff */
291extern struct attribute_group cros_ec_attr_group;
292extern struct attribute_group cros_ec_lightbar_attr_group;
293extern struct attribute_group cros_ec_vbc_attr_group;
294
295#endif /* __LINUX_MFD_CROS_EC_H */