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Linux 4.19.133
[linux/fpc-iii.git] / drivers / platform / chrome / cros_ec_proto.c
blobac784ac66ac341f754d59bd6a7a70c61d1fd0915
1 /*
2 * ChromeOS EC communication protocol helper functions
3 *
4 * Copyright (C) 2015 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
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>
23
24 #define EC_COMMAND_RETRIES 50
25
26 static int prepare_packet(struct cros_ec_device *ec_dev,
27 struct cros_ec_command *msg)
28 {
29 struct ec_host_request *request;
30 u8 *out;
31 int i;
32 u8 csum = 0;
33
34 BUG_ON(ec_dev->proto_version != EC_HOST_REQUEST_VERSION);
35 BUG_ON(msg->outsize + sizeof(*request) > ec_dev->dout_size);
36
37 out = ec_dev->dout;
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;
45
46 for (i = 0; i < sizeof(*request); i++)
47 csum += out[i];
48
49 /* Copy data and update checksum */
50 memcpy(out + sizeof(*request), msg->data, msg->outsize);
51 for (i = 0; i < msg->outsize; i++)
52 csum += msg->data[i];
53
54 request->checksum = -csum;
55
56 return sizeof(*request) + msg->outsize;
57 }
58
59 static int send_command(struct cros_ec_device *ec_dev,
60 struct cros_ec_command *msg)
61 {
62 int ret;
63 int (*xfer_fxn)(struct cros_ec_device *ec, struct cros_ec_command *msg);
64
65 if (ec_dev->proto_version > 2)
66 xfer_fxn = ec_dev->pkt_xfer;
67 else
68 xfer_fxn = ec_dev->cmd_xfer;
69
70 if (!xfer_fxn) {
71 /*
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.
75 */
76 dev_err_once(ec_dev->dev,
77 "missing EC transfer API, cannot send command\n");
78 return -EIO;
79 }
80
81 ret = (*xfer_fxn)(ec_dev, msg);
82 if (msg->result == EC_RES_IN_PROGRESS) {
83 int i;
84 struct cros_ec_command *status_msg;
85 struct ec_response_get_comms_status *status;
86
87 status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
88 GFP_KERNEL);
89 if (!status_msg)
90 return -ENOMEM;
91
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;
96
97 /*
98 * Query the EC's status until it's no longer busy or
99 * we encounter an error.
100 */
101 for (i = 0; i < EC_COMMAND_RETRIES; i++) {
102 usleep_range(10000, 11000);
103
104 ret = (*xfer_fxn)(ec_dev, status_msg);
105 if (ret == -EAGAIN)
106 continue;
107 if (ret < 0)
108 break;
109
110 msg->result = status_msg->result;
111 if (status_msg->result != EC_RES_SUCCESS)
112 break;
113
114 status = (struct ec_response_get_comms_status *)
115 status_msg->data;
116 if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
117 break;
118 }
119
120 kfree(status_msg);
121 }
122
123 return ret;
124 }
125
126 int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
127 struct cros_ec_command *msg)
128 {
129 u8 *out;
130 u8 csum;
131 int i;
132
133 if (ec_dev->proto_version > 2)
134 return prepare_packet(ec_dev, msg);
135
136 BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
137 out = ec_dev->dout;
138 out[0] = EC_CMD_VERSION0 + msg->version;
139 out[1] = msg->command;
140 out[2] = msg->outsize;
141 csum = out[0] + out[1] + out[2];
142 for (i = 0; i < msg->outsize; i++)
143 csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
144 out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum;
145
146 return EC_MSG_TX_PROTO_BYTES + msg->outsize;
147 }
148 EXPORT_SYMBOL(cros_ec_prepare_tx);
149
150 int cros_ec_check_result(struct cros_ec_device *ec_dev,
151 struct cros_ec_command *msg)
152 {
153 switch (msg->result) {
154 case EC_RES_SUCCESS:
155 return 0;
156 case EC_RES_IN_PROGRESS:
157 dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
158 msg->command);
159 return -EAGAIN;
160 default:
161 dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
162 msg->command, msg->result);
163 return 0;
164 }
165 }
166 EXPORT_SYMBOL(cros_ec_check_result);
167
168 /*
169 * cros_ec_get_host_event_wake_mask
170 *
171 * Get the mask of host events that cause wake from suspend.
172 *
173 * @ec_dev: EC device to call
174 * @msg: message structure to use
175 * @mask: result when function returns >=0.
176 *
177 * LOCKING:
178 * the caller has ec_dev->lock mutex, or the caller knows there is
179 * no other command in progress.
180 */
181 static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev,
182 struct cros_ec_command *msg,
183 uint32_t *mask)
184 {
185 struct ec_response_host_event_mask *r;
186 int ret;
187
188 msg->command = EC_CMD_HOST_EVENT_GET_WAKE_MASK;
189 msg->version = 0;
190 msg->outsize = 0;
191 msg->insize = sizeof(*r);
192
193 ret = send_command(ec_dev, msg);
194 if (ret > 0) {
195 r = (struct ec_response_host_event_mask *)msg->data;
196 *mask = r->mask;
197 }
198
199 return ret;
200 }
201
202 static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev,
203 int devidx,
204 struct cros_ec_command *msg)
205 {
206 /*
207 * Try using v3+ to query for supported protocols. If this
208 * command fails, fall back to v2. Returns the highest protocol
209 * supported by the EC.
210 * Also sets the max request/response/passthru size.
211 */
212 int ret;
213
214 if (!ec_dev->pkt_xfer)
215 return -EPROTONOSUPPORT;
216
217 memset(msg, 0, sizeof(*msg));
218 msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO;
219 msg->insize = sizeof(struct ec_response_get_protocol_info);
220
221 ret = send_command(ec_dev, msg);
222
223 if (ret < 0) {
224 dev_dbg(ec_dev->dev,
225 "failed to check for EC[%d] protocol version: %d\n",
226 devidx, ret);
227 return ret;
228 }
229
230 if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND)
231 return -ENODEV;
232 else if (msg->result != EC_RES_SUCCESS)
233 return msg->result;
234
235 return 0;
236 }
237
238 static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev)
239 {
240 struct cros_ec_command *msg;
241 struct ec_params_hello *hello_params;
242 struct ec_response_hello *hello_response;
243 int ret;
244 int len = max(sizeof(*hello_params), sizeof(*hello_response));
245
246 msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
247 if (!msg)
248 return -ENOMEM;
249
250 msg->version = 0;
251 msg->command = EC_CMD_HELLO;
252 hello_params = (struct ec_params_hello *)msg->data;
253 msg->outsize = sizeof(*hello_params);
254 hello_response = (struct ec_response_hello *)msg->data;
255 msg->insize = sizeof(*hello_response);
256
257 hello_params->in_data = 0xa0b0c0d0;
258
259 ret = send_command(ec_dev, msg);
260
261 if (ret < 0) {
262 dev_dbg(ec_dev->dev,
263 "EC failed to respond to v2 hello: %d\n",
264 ret);
265 goto exit;
266 } else if (msg->result != EC_RES_SUCCESS) {
267 dev_err(ec_dev->dev,
268 "EC responded to v2 hello with error: %d\n",
269 msg->result);
270 ret = msg->result;
271 goto exit;
272 } else if (hello_response->out_data != 0xa1b2c3d4) {
273 dev_err(ec_dev->dev,
274 "EC responded to v2 hello with bad result: %u\n",
275 hello_response->out_data);
276 ret = -EBADMSG;
277 goto exit;
278 }
279
280 ret = 0;
281
282 exit:
283 kfree(msg);
284 return ret;
285 }
286
287 /*
288 * cros_ec_get_host_command_version_mask
289 *
290 * Get the version mask of a given command.
291 *
292 * @ec_dev: EC device to call
293 * @msg: message structure to use
294 * @cmd: command to get the version of.
295 * @mask: result when function returns 0.
296 *
297 * @return 0 on success, error code otherwise
298 *
299 * LOCKING:
300 * the caller has ec_dev->lock mutex or the caller knows there is
301 * no other command in progress.
302 */
303 static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev,
304 u16 cmd, u32 *mask)
305 {
306 struct ec_params_get_cmd_versions *pver;
307 struct ec_response_get_cmd_versions *rver;
308 struct cros_ec_command *msg;
309 int ret;
310
311 msg = kmalloc(sizeof(*msg) + max(sizeof(*rver), sizeof(*pver)),
312 GFP_KERNEL);
313 if (!msg)
314 return -ENOMEM;
315
316 msg->version = 0;
317 msg->command = EC_CMD_GET_CMD_VERSIONS;
318 msg->insize = sizeof(*rver);
319 msg->outsize = sizeof(*pver);
320
321 pver = (struct ec_params_get_cmd_versions *)msg->data;
322 pver->cmd = cmd;
323
324 ret = send_command(ec_dev, msg);
325 if (ret > 0) {
326 rver = (struct ec_response_get_cmd_versions *)msg->data;
327 *mask = rver->version_mask;
328 }
329
330 kfree(msg);
331
332 return ret;
333 }
334
335 int cros_ec_query_all(struct cros_ec_device *ec_dev)
336 {
337 struct device *dev = ec_dev->dev;
338 struct cros_ec_command *proto_msg;
339 struct ec_response_get_protocol_info *proto_info;
340 u32 ver_mask = 0;
341 int ret;
342
343 proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info),
344 GFP_KERNEL);
345 if (!proto_msg)
346 return -ENOMEM;
347
348 /* First try sending with proto v3. */
349 ec_dev->proto_version = 3;
350 ret = cros_ec_host_command_proto_query(ec_dev, 0, proto_msg);
351
352 if (ret == 0) {
353 proto_info = (struct ec_response_get_protocol_info *)
354 proto_msg->data;
355 ec_dev->max_request = proto_info->max_request_packet_size -
356 sizeof(struct ec_host_request);
357 ec_dev->max_response = proto_info->max_response_packet_size -
358 sizeof(struct ec_host_response);
359 ec_dev->proto_version =
360 min(EC_HOST_REQUEST_VERSION,
361 fls(proto_info->protocol_versions) - 1);
362 dev_dbg(ec_dev->dev,
363 "using proto v%u\n",
364 ec_dev->proto_version);
365
366 ec_dev->din_size = ec_dev->max_response +
367 sizeof(struct ec_host_response) +
368 EC_MAX_RESPONSE_OVERHEAD;
369 ec_dev->dout_size = ec_dev->max_request +
370 sizeof(struct ec_host_request) +
371 EC_MAX_REQUEST_OVERHEAD;
372
373 /*
374 * Check for PD
375 */
376 ret = cros_ec_host_command_proto_query(ec_dev, 1, proto_msg);
377
378 if (ret) {
379 dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret);
380 ec_dev->max_passthru = 0;
381 } else {
382 dev_dbg(ec_dev->dev, "found PD chip\n");
383 ec_dev->max_passthru =
384 proto_info->max_request_packet_size -
385 sizeof(struct ec_host_request);
386 }
387 } else {
388 /* Try querying with a v2 hello message. */
389 ec_dev->proto_version = 2;
390 ret = cros_ec_host_command_proto_query_v2(ec_dev);
391
392 if (ret == 0) {
393 /* V2 hello succeeded. */
394 dev_dbg(ec_dev->dev, "falling back to proto v2\n");
395
396 ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE;
397 ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE;
398 ec_dev->max_passthru = 0;
399 ec_dev->pkt_xfer = NULL;
400 ec_dev->din_size = EC_PROTO2_MSG_BYTES;
401 ec_dev->dout_size = EC_PROTO2_MSG_BYTES;
402 } else {
403 /*
404 * It's possible for a test to occur too early when
405 * the EC isn't listening. If this happens, we'll
406 * test later when the first command is run.
407 */
408 ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN;
409 dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret);
410 goto exit;
411 }
412 }
413
414 devm_kfree(dev, ec_dev->din);
415 devm_kfree(dev, ec_dev->dout);
416
417 ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
418 if (!ec_dev->din) {
419 ret = -ENOMEM;
420 goto exit;
421 }
422
423 ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
424 if (!ec_dev->dout) {
425 devm_kfree(dev, ec_dev->din);
426 ret = -ENOMEM;
427 goto exit;
428 }
429
430 /* Probe if MKBP event is supported */
431 ret = cros_ec_get_host_command_version_mask(ec_dev,
432 EC_CMD_GET_NEXT_EVENT,
433 &ver_mask);
434 if (ret < 0 || ver_mask == 0)
435 ec_dev->mkbp_event_supported = 0;
436 else
437 ec_dev->mkbp_event_supported = 1;
438
439 /*
440 * Get host event wake mask, assume all events are wake events
441 * if unavailable.
442 */
443 ret = cros_ec_get_host_event_wake_mask(ec_dev, proto_msg,
444 &ec_dev->host_event_wake_mask);
445 if (ret < 0)
446 ec_dev->host_event_wake_mask = U32_MAX;
447
448 ret = 0;
449
450 exit:
451 kfree(proto_msg);
452 return ret;
453 }
454 EXPORT_SYMBOL(cros_ec_query_all);
455
456 int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
457 struct cros_ec_command *msg)
458 {
459 int ret;
460
461 mutex_lock(&ec_dev->lock);
462 if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) {
463 ret = cros_ec_query_all(ec_dev);
464 if (ret) {
465 dev_err(ec_dev->dev,
466 "EC version unknown and query failed; aborting command\n");
467 mutex_unlock(&ec_dev->lock);
468 return ret;
469 }
470 }
471
472 if (msg->insize > ec_dev->max_response) {
473 dev_dbg(ec_dev->dev, "clamping message receive buffer\n");
474 msg->insize = ec_dev->max_response;
475 }
476
477 if (msg->command < EC_CMD_PASSTHRU_OFFSET(1)) {
478 if (msg->outsize > ec_dev->max_request) {
479 dev_err(ec_dev->dev,
480 "request of size %u is too big (max: %u)\n",
481 msg->outsize,
482 ec_dev->max_request);
483 mutex_unlock(&ec_dev->lock);
484 return -EMSGSIZE;
485 }
486 } else {
487 if (msg->outsize > ec_dev->max_passthru) {
488 dev_err(ec_dev->dev,
489 "passthru rq of size %u is too big (max: %u)\n",
490 msg->outsize,
491 ec_dev->max_passthru);
492 mutex_unlock(&ec_dev->lock);
493 return -EMSGSIZE;
494 }
495 }
496 ret = send_command(ec_dev, msg);
497 mutex_unlock(&ec_dev->lock);
498
499 return ret;
500 }
501 EXPORT_SYMBOL(cros_ec_cmd_xfer);
502
503 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
504 struct cros_ec_command *msg)
505 {
506 int ret;
507
508 ret = cros_ec_cmd_xfer(ec_dev, msg);
509 if (ret < 0) {
510 dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
511 } else if (msg->result != EC_RES_SUCCESS) {
512 dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result);
513 return -EPROTO;
514 }
515
516 return ret;
517 }
518 EXPORT_SYMBOL(cros_ec_cmd_xfer_status);
519
520 static int get_next_event_xfer(struct cros_ec_device *ec_dev,
521 struct cros_ec_command *msg,
522 int version, uint32_t size)
523 {
524 int ret;
525
526 msg->version = version;
527 msg->command = EC_CMD_GET_NEXT_EVENT;
528 msg->insize = size;
529 msg->outsize = 0;
530
531 ret = cros_ec_cmd_xfer(ec_dev, msg);
532 if (ret > 0) {
533 ec_dev->event_size = ret - 1;
534 memcpy(&ec_dev->event_data, msg->data, ret);
535 }
536
537 return ret;
538 }
539
540 static int get_next_event(struct cros_ec_device *ec_dev)
541 {
542 u8 buffer[sizeof(struct cros_ec_command) + sizeof(ec_dev->event_data)];
543 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
544 static int cmd_version = 1;
545 int ret;
546
547 if (ec_dev->suspended) {
548 dev_dbg(ec_dev->dev, "Device suspended.\n");
549 return -EHOSTDOWN;
550 }
551
552 if (cmd_version == 1) {
553 ret = get_next_event_xfer(ec_dev, msg, cmd_version,
554 sizeof(struct ec_response_get_next_event_v1));
555 if (ret < 0 || msg->result != EC_RES_INVALID_VERSION)
556 return ret;
557
558 /* Fallback to version 0 for future send attempts */
559 cmd_version = 0;
560 }
561
562 ret = get_next_event_xfer(ec_dev, msg, cmd_version,
563 sizeof(struct ec_response_get_next_event));
564
565 return ret;
566 }
567
568 static int get_keyboard_state_event(struct cros_ec_device *ec_dev)
569 {
570 u8 buffer[sizeof(struct cros_ec_command) +
571 sizeof(ec_dev->event_data.data)];
572 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
573
574 msg->version = 0;
575 msg->command = EC_CMD_MKBP_STATE;
576 msg->insize = sizeof(ec_dev->event_data.data);
577 msg->outsize = 0;
578
579 ec_dev->event_size = cros_ec_cmd_xfer(ec_dev, msg);
580 ec_dev->event_data.event_type = EC_MKBP_EVENT_KEY_MATRIX;
581 memcpy(&ec_dev->event_data.data, msg->data,
582 sizeof(ec_dev->event_data.data));
583
584 return ec_dev->event_size;
585 }
586
587 int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event)
588 {
589 u8 event_type;
590 u32 host_event;
591 int ret;
592
593 if (!ec_dev->mkbp_event_supported) {
594 ret = get_keyboard_state_event(ec_dev);
595 if (ret < 0)
596 return ret;
597
598 if (wake_event)
599 *wake_event = true;
600
601 return ret;
602 }
603
604 ret = get_next_event(ec_dev);
605 if (ret < 0)
606 return ret;
607
608 if (wake_event) {
609 event_type = ec_dev->event_data.event_type;
610 host_event = cros_ec_get_host_event(ec_dev);
611
612 /*
613 * Sensor events need to be parsed by the sensor sub-device.
614 * Defer them, and don't report the wakeup here.
615 */
616 if (event_type == EC_MKBP_EVENT_SENSOR_FIFO)
617 *wake_event = false;
618 /* Masked host-events should not count as wake events. */
619 else if (host_event &&
620 !(host_event & ec_dev->host_event_wake_mask))
621 *wake_event = false;
622 /* Consider all other events as wake events. */
623 else
624 *wake_event = true;
625 }
626
627 return ret;
628 }
629 EXPORT_SYMBOL(cros_ec_get_next_event);
630
631 u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev)
632 {
633 u32 host_event;
634
635 BUG_ON(!ec_dev->mkbp_event_supported);
636
637 if (ec_dev->event_data.event_type != EC_MKBP_EVENT_HOST_EVENT)
638 return 0;
639
640 if (ec_dev->event_size != sizeof(host_event)) {
641 dev_warn(ec_dev->dev, "Invalid host event size\n");
642 return 0;
643 }
644
645 host_event = get_unaligned_le32(&ec_dev->event_data.data.host_event);
646
647 return host_event;
648 }
649 EXPORT_SYMBOL(cros_ec_get_host_event);
Linux with added FPC-III support