2 * ChromeOS EC communication protocol helper functions
4 * Copyright (C) 2015 Google, Inc
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.
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.
17 #include <linux/mfd/cros_ec.h>
18 #include <linux/delay.h>
19 #include <linux/device.h>
20 #include <linux/module.h>
21 #include <linux/slab.h>
22 #include <asm/unaligned.h>
24 #define EC_COMMAND_RETRIES 50
26 static int prepare_packet(struct cros_ec_device *ec_dev,
27 struct cros_ec_command *msg)
29 struct ec_host_request *request;
34 BUG_ON(ec_dev->proto_version != EC_HOST_REQUEST_VERSION);
35 BUG_ON(msg->outsize + sizeof(*request) > ec_dev->dout_size);
38 request = (struct ec_host_request *)out;
39 request->struct_version = EC_HOST_REQUEST_VERSION;
40 request->checksum = 0;
41 request->command = msg->command;
42 request->command_version = msg->version;
43 request->reserved = 0;
44 request->data_len = msg->outsize;
46 for (i = 0; i < sizeof(*request); i++)
49 /* Copy data and update checksum */
50 memcpy(out + sizeof(*request), msg->data, msg->outsize);
51 for (i = 0; i < msg->outsize; i++)
54 request->checksum = -csum;
56 return sizeof(*request) + msg->outsize;
59 static int send_command(struct cros_ec_device *ec_dev,
60 struct cros_ec_command *msg)
63 int (*xfer_fxn)(struct cros_ec_device *ec, struct cros_ec_command *msg);
65 if (ec_dev->proto_version > 2)
66 xfer_fxn = ec_dev->pkt_xfer;
68 xfer_fxn = ec_dev->cmd_xfer;
72 * This error can happen if a communication error happened and
73 * the EC is trying to use protocol v2, on an underlying
74 * communication mechanism that does not support v2.
76 dev_err_once(ec_dev->dev,
77 "missing EC transfer API, cannot send command\n");
81 ret = (*xfer_fxn)(ec_dev, msg);
82 if (msg->result == EC_RES_IN_PROGRESS) {
84 struct cros_ec_command *status_msg;
85 struct ec_response_get_comms_status *status;
87 status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
92 status_msg->version = 0;
93 status_msg->command = EC_CMD_GET_COMMS_STATUS;
94 status_msg->insize = sizeof(*status);
95 status_msg->outsize = 0;
98 * Query the EC's status until it's no longer busy or
99 * we encounter an error.
101 for (i = 0; i < EC_COMMAND_RETRIES; i++) {
102 usleep_range(10000, 11000);
104 ret = (*xfer_fxn)(ec_dev, status_msg);
108 msg->result = status_msg->result;
109 if (status_msg->result != EC_RES_SUCCESS)
112 status = (struct ec_response_get_comms_status *)
114 if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
124 int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
125 struct cros_ec_command *msg)
131 if (ec_dev->proto_version > 2)
132 return prepare_packet(ec_dev, msg);
134 BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
136 out[0] = EC_CMD_VERSION0 + msg->version;
137 out[1] = msg->command;
138 out[2] = msg->outsize;
139 csum = out[0] + out[1] + out[2];
140 for (i = 0; i < msg->outsize; i++)
141 csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
142 out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum;
144 return EC_MSG_TX_PROTO_BYTES + msg->outsize;
146 EXPORT_SYMBOL(cros_ec_prepare_tx);
148 int cros_ec_check_result(struct cros_ec_device *ec_dev,
149 struct cros_ec_command *msg)
151 switch (msg->result) {
154 case EC_RES_IN_PROGRESS:
155 dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
159 dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
160 msg->command, msg->result);
164 EXPORT_SYMBOL(cros_ec_check_result);
167 * cros_ec_get_host_event_wake_mask
169 * Get the mask of host events that cause wake from suspend.
171 * @ec_dev: EC device to call
172 * @msg: message structure to use
173 * @mask: result when function returns >=0.
176 * the caller has ec_dev->lock mutex, or the caller knows there is
177 * no other command in progress.
179 static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev,
180 struct cros_ec_command *msg,
183 struct ec_response_host_event_mask *r;
186 msg->command = EC_CMD_HOST_EVENT_GET_WAKE_MASK;
189 msg->insize = sizeof(*r);
191 ret = send_command(ec_dev, msg);
193 r = (struct ec_response_host_event_mask *)msg->data;
200 static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev,
202 struct cros_ec_command *msg)
205 * Try using v3+ to query for supported protocols. If this
206 * command fails, fall back to v2. Returns the highest protocol
207 * supported by the EC.
208 * Also sets the max request/response/passthru size.
212 if (!ec_dev->pkt_xfer)
213 return -EPROTONOSUPPORT;
215 memset(msg, 0, sizeof(*msg));
216 msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO;
217 msg->insize = sizeof(struct ec_response_get_protocol_info);
219 ret = send_command(ec_dev, msg);
221 * Send command once again when timeout occurred.
222 * Fingerprint MCU (FPMCU) is restarted during system boot which
223 * introduces small window in which FPMCU won't respond for any
224 * messages sent by kernel. There is no need to wait before next
225 * attempt because we waited at least EC_MSG_DEADLINE_MS.
227 if (ret == -ETIMEDOUT)
228 ret = send_command(ec_dev, msg);
232 "failed to check for EC[%d] protocol version: %d\n",
237 if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND)
239 else if (msg->result != EC_RES_SUCCESS)
245 static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev)
247 struct cros_ec_command *msg;
248 struct ec_params_hello *hello_params;
249 struct ec_response_hello *hello_response;
251 int len = max(sizeof(*hello_params), sizeof(*hello_response));
253 msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
258 msg->command = EC_CMD_HELLO;
259 hello_params = (struct ec_params_hello *)msg->data;
260 msg->outsize = sizeof(*hello_params);
261 hello_response = (struct ec_response_hello *)msg->data;
262 msg->insize = sizeof(*hello_response);
264 hello_params->in_data = 0xa0b0c0d0;
266 ret = send_command(ec_dev, msg);
270 "EC failed to respond to v2 hello: %d\n",
273 } else if (msg->result != EC_RES_SUCCESS) {
275 "EC responded to v2 hello with error: %d\n",
279 } else if (hello_response->out_data != 0xa1b2c3d4) {
281 "EC responded to v2 hello with bad result: %u\n",
282 hello_response->out_data);
295 * cros_ec_get_host_command_version_mask
297 * Get the version mask of a given command.
299 * @ec_dev: EC device to call
300 * @msg: message structure to use
301 * @cmd: command to get the version of.
302 * @mask: result when function returns 0.
304 * @return 0 on success, error code otherwise
307 * the caller has ec_dev->lock mutex or the caller knows there is
308 * no other command in progress.
310 static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev,
313 struct ec_params_get_cmd_versions *pver;
314 struct ec_response_get_cmd_versions *rver;
315 struct cros_ec_command *msg;
318 msg = kmalloc(sizeof(*msg) + max(sizeof(*rver), sizeof(*pver)),
324 msg->command = EC_CMD_GET_CMD_VERSIONS;
325 msg->insize = sizeof(*rver);
326 msg->outsize = sizeof(*pver);
328 pver = (struct ec_params_get_cmd_versions *)msg->data;
331 ret = send_command(ec_dev, msg);
333 rver = (struct ec_response_get_cmd_versions *)msg->data;
334 *mask = rver->version_mask;
342 int cros_ec_query_all(struct cros_ec_device *ec_dev)
344 struct device *dev = ec_dev->dev;
345 struct cros_ec_command *proto_msg;
346 struct ec_response_get_protocol_info *proto_info;
350 proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info),
355 /* First try sending with proto v3. */
356 ec_dev->proto_version = 3;
357 ret = cros_ec_host_command_proto_query(ec_dev, 0, proto_msg);
360 proto_info = (struct ec_response_get_protocol_info *)
362 ec_dev->max_request = proto_info->max_request_packet_size -
363 sizeof(struct ec_host_request);
364 ec_dev->max_response = proto_info->max_response_packet_size -
365 sizeof(struct ec_host_response);
366 ec_dev->proto_version =
367 min(EC_HOST_REQUEST_VERSION,
368 fls(proto_info->protocol_versions) - 1);
371 ec_dev->proto_version);
373 ec_dev->din_size = ec_dev->max_response +
374 sizeof(struct ec_host_response) +
375 EC_MAX_RESPONSE_OVERHEAD;
376 ec_dev->dout_size = ec_dev->max_request +
377 sizeof(struct ec_host_request) +
378 EC_MAX_REQUEST_OVERHEAD;
383 ret = cros_ec_host_command_proto_query(ec_dev, 1, proto_msg);
386 dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret);
387 ec_dev->max_passthru = 0;
389 dev_dbg(ec_dev->dev, "found PD chip\n");
390 ec_dev->max_passthru =
391 proto_info->max_request_packet_size -
392 sizeof(struct ec_host_request);
395 /* Try querying with a v2 hello message. */
396 ec_dev->proto_version = 2;
397 ret = cros_ec_host_command_proto_query_v2(ec_dev);
400 /* V2 hello succeeded. */
401 dev_dbg(ec_dev->dev, "falling back to proto v2\n");
403 ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE;
404 ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE;
405 ec_dev->max_passthru = 0;
406 ec_dev->pkt_xfer = NULL;
407 ec_dev->din_size = EC_PROTO2_MSG_BYTES;
408 ec_dev->dout_size = EC_PROTO2_MSG_BYTES;
411 * It's possible for a test to occur too early when
412 * the EC isn't listening. If this happens, we'll
413 * test later when the first command is run.
415 ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN;
416 dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret);
421 devm_kfree(dev, ec_dev->din);
422 devm_kfree(dev, ec_dev->dout);
424 ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
430 ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
432 devm_kfree(dev, ec_dev->din);
437 /* Probe if MKBP event is supported */
438 ret = cros_ec_get_host_command_version_mask(ec_dev,
439 EC_CMD_GET_NEXT_EVENT,
441 if (ret < 0 || ver_mask == 0)
442 ec_dev->mkbp_event_supported = 0;
444 ec_dev->mkbp_event_supported = 1;
447 * Get host event wake mask, assume all events are wake events
450 ret = cros_ec_get_host_event_wake_mask(ec_dev, proto_msg,
451 &ec_dev->host_event_wake_mask);
453 ec_dev->host_event_wake_mask = U32_MAX;
461 EXPORT_SYMBOL(cros_ec_query_all);
463 int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
464 struct cros_ec_command *msg)
468 mutex_lock(&ec_dev->lock);
469 if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) {
470 ret = cros_ec_query_all(ec_dev);
473 "EC version unknown and query failed; aborting command\n");
474 mutex_unlock(&ec_dev->lock);
479 if (msg->insize > ec_dev->max_response) {
480 dev_dbg(ec_dev->dev, "clamping message receive buffer\n");
481 msg->insize = ec_dev->max_response;
484 if (msg->command < EC_CMD_PASSTHRU_OFFSET(1)) {
485 if (msg->outsize > ec_dev->max_request) {
487 "request of size %u is too big (max: %u)\n",
489 ec_dev->max_request);
490 mutex_unlock(&ec_dev->lock);
494 if (msg->outsize > ec_dev->max_passthru) {
496 "passthru rq of size %u is too big (max: %u)\n",
498 ec_dev->max_passthru);
499 mutex_unlock(&ec_dev->lock);
503 ret = send_command(ec_dev, msg);
504 mutex_unlock(&ec_dev->lock);
508 EXPORT_SYMBOL(cros_ec_cmd_xfer);
510 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
511 struct cros_ec_command *msg)
515 ret = cros_ec_cmd_xfer(ec_dev, msg);
517 dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
518 } else if (msg->result != EC_RES_SUCCESS) {
519 dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result);
525 EXPORT_SYMBOL(cros_ec_cmd_xfer_status);
527 static int get_next_event(struct cros_ec_device *ec_dev)
529 u8 buffer[sizeof(struct cros_ec_command) + sizeof(ec_dev->event_data)];
530 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
533 if (ec_dev->suspended) {
534 dev_dbg(ec_dev->dev, "Device suspended.\n");
539 msg->command = EC_CMD_GET_NEXT_EVENT;
540 msg->insize = sizeof(ec_dev->event_data);
543 ret = cros_ec_cmd_xfer(ec_dev, msg);
545 ec_dev->event_size = ret - 1;
546 memcpy(&ec_dev->event_data, msg->data,
547 sizeof(ec_dev->event_data));
553 static int get_keyboard_state_event(struct cros_ec_device *ec_dev)
555 u8 buffer[sizeof(struct cros_ec_command) +
556 sizeof(ec_dev->event_data.data)];
557 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
560 msg->command = EC_CMD_MKBP_STATE;
561 msg->insize = sizeof(ec_dev->event_data.data);
564 ec_dev->event_size = cros_ec_cmd_xfer(ec_dev, msg);
565 ec_dev->event_data.event_type = EC_MKBP_EVENT_KEY_MATRIX;
566 memcpy(&ec_dev->event_data.data, msg->data,
567 sizeof(ec_dev->event_data.data));
569 return ec_dev->event_size;
572 int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event)
578 if (!ec_dev->mkbp_event_supported) {
579 ret = get_keyboard_state_event(ec_dev);
589 ret = get_next_event(ec_dev);
594 event_type = ec_dev->event_data.event_type;
595 host_event = cros_ec_get_host_event(ec_dev);
598 * Sensor events need to be parsed by the sensor sub-device.
599 * Defer them, and don't report the wakeup here.
601 if (event_type == EC_MKBP_EVENT_SENSOR_FIFO)
603 /* Masked host-events should not count as wake events. */
604 else if (host_event &&
605 !(host_event & ec_dev->host_event_wake_mask))
607 /* Consider all other events as wake events. */
614 EXPORT_SYMBOL(cros_ec_get_next_event);
616 u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev)
620 BUG_ON(!ec_dev->mkbp_event_supported);
622 if (ec_dev->event_data.event_type != EC_MKBP_EVENT_HOST_EVENT)
625 if (ec_dev->event_size != sizeof(host_event)) {
626 dev_warn(ec_dev->dev, "Invalid host event size\n");
630 host_event = get_unaligned_le32(&ec_dev->event_data.data.host_event);
634 EXPORT_SYMBOL(cros_ec_get_host_event);