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1// SPDX-License-Identifier: GPL-2.0
2// ChromeOS EC communication protocol helper functions
3//
4// Copyright (C) 2015 Google, Inc
5
6#include <linux/delay.h>
7#include <linux/device.h>
8#include <linux/module.h>
9#include <linux/platform_data/cros_ec_commands.h>
10#include <linux/platform_data/cros_ec_proto.h>
11#include <linux/slab.h>
12#include <asm/unaligned.h>
13
14#include "cros_ec_trace.h"
15
16#define EC_COMMAND_RETRIES 50
17
18static int prepare_packet(struct cros_ec_device *ec_dev,
19 struct cros_ec_command *msg)
20{
21 struct ec_host_request *request;
22 u8 *out;
23 int i;
24 u8 csum = 0;
25
26 BUG_ON(ec_dev->proto_version != EC_HOST_REQUEST_VERSION);
27 BUG_ON(msg->outsize + sizeof(*request) > ec_dev->dout_size);
28
29 out = ec_dev->dout;
30 request = (struct ec_host_request *)out;
31 request->struct_version = EC_HOST_REQUEST_VERSION;
32 request->checksum = 0;
33 request->command = msg->command;
34 request->command_version = msg->version;
35 request->reserved = 0;
36 request->data_len = msg->outsize;
37
38 for (i = 0; i < sizeof(*request); i++)
39 csum += out[i];
40
41 /* Copy data and update checksum */
42 memcpy(out + sizeof(*request), msg->data, msg->outsize);
43 for (i = 0; i < msg->outsize; i++)
44 csum += msg->data[i];
45
46 request->checksum = -csum;
47
48 return sizeof(*request) + msg->outsize;
49}
50
51static int send_command(struct cros_ec_device *ec_dev,
52 struct cros_ec_command *msg)
53{
54 int ret;
55 int (*xfer_fxn)(struct cros_ec_device *ec, struct cros_ec_command *msg);
56
57 trace_cros_ec_cmd(msg);
58
59 if (ec_dev->proto_version > 2)
60 xfer_fxn = ec_dev->pkt_xfer;
61 else
62 xfer_fxn = ec_dev->cmd_xfer;
63
64 if (!xfer_fxn) {
65 /*
66 * This error can happen if a communication error happened and
67 * the EC is trying to use protocol v2, on an underlying
68 * communication mechanism that does not support v2.
69 */
70 dev_err_once(ec_dev->dev,
71 "missing EC transfer API, cannot send command\n");
72 return -EIO;
73 }
74
75 ret = (*xfer_fxn)(ec_dev, msg);
76 if (msg->result == EC_RES_IN_PROGRESS) {
77 int i;
78 struct cros_ec_command *status_msg;
79 struct ec_response_get_comms_status *status;
80
81 status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
82 GFP_KERNEL);
83 if (!status_msg)
84 return -ENOMEM;
85
86 status_msg->version = 0;
87 status_msg->command = EC_CMD_GET_COMMS_STATUS;
88 status_msg->insize = sizeof(*status);
89 status_msg->outsize = 0;
90
91 /*
92 * Query the EC's status until it's no longer busy or
93 * we encounter an error.
94 */
95 for (i = 0; i < EC_COMMAND_RETRIES; i++) {
96 usleep_range(10000, 11000);
97
98 ret = (*xfer_fxn)(ec_dev, status_msg);
99 if (ret == -EAGAIN)
100 continue;
101 if (ret < 0)
102 break;
103
104 msg->result = status_msg->result;
105 if (status_msg->result != EC_RES_SUCCESS)
106 break;
107
108 status = (struct ec_response_get_comms_status *)
109 status_msg->data;
110 if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
111 break;
112 }
113
114 kfree(status_msg);
115 }
116
117 return ret;
118}
119
120int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
121 struct cros_ec_command *msg)
122{
123 u8 *out;
124 u8 csum;
125 int i;
126
127 if (ec_dev->proto_version > 2)
128 return prepare_packet(ec_dev, msg);
129
130 BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
131 out = ec_dev->dout;
132 out[0] = EC_CMD_VERSION0 + msg->version;
133 out[1] = msg->command;
134 out[2] = msg->outsize;
135 csum = out[0] + out[1] + out[2];
136 for (i = 0; i < msg->outsize; i++)
137 csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
138 out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum;
139
140 return EC_MSG_TX_PROTO_BYTES + msg->outsize;
141}
142EXPORT_SYMBOL(cros_ec_prepare_tx);
143
144int cros_ec_check_result(struct cros_ec_device *ec_dev,
145 struct cros_ec_command *msg)
146{
147 switch (msg->result) {
148 case EC_RES_SUCCESS:
149 return 0;
150 case EC_RES_IN_PROGRESS:
151 dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
152 msg->command);
153 return -EAGAIN;
154 default:
155 dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
156 msg->command, msg->result);
157 return 0;
158 }
159}
160EXPORT_SYMBOL(cros_ec_check_result);
161
162/*
163 * cros_ec_get_host_event_wake_mask
164 *
165 * Get the mask of host events that cause wake from suspend.
166 *
167 * @ec_dev: EC device to call
168 * @msg: message structure to use
169 * @mask: result when function returns >=0.
170 *
171 * LOCKING:
172 * the caller has ec_dev->lock mutex, or the caller knows there is
173 * no other command in progress.
174 */
175static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev,
176 struct cros_ec_command *msg,
177 uint32_t *mask)
178{
179 struct ec_response_host_event_mask *r;
180 int ret;
181
182 msg->command = EC_CMD_HOST_EVENT_GET_WAKE_MASK;
183 msg->version = 0;
184 msg->outsize = 0;
185 msg->insize = sizeof(*r);
186
187 ret = send_command(ec_dev, msg);
188 if (ret > 0) {
189 r = (struct ec_response_host_event_mask *)msg->data;
190 *mask = r->mask;
191 }
192
193 return ret;
194}
195
196static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev,
197 int devidx,
198 struct cros_ec_command *msg)
199{
200 /*
201 * Try using v3+ to query for supported protocols. If this
202 * command fails, fall back to v2. Returns the highest protocol
203 * supported by the EC.
204 * Also sets the max request/response/passthru size.
205 */
206 int ret;
207
208 if (!ec_dev->pkt_xfer)
209 return -EPROTONOSUPPORT;
210
211 memset(msg, 0, sizeof(*msg));
212 msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO;
213 msg->insize = sizeof(struct ec_response_get_protocol_info);
214
215 ret = send_command(ec_dev, msg);
216
217 if (ret < 0) {
218 dev_dbg(ec_dev->dev,
219 "failed to check for EC[%d] protocol version: %d\n",
220 devidx, ret);
221 return ret;
222 }
223
224 if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND)
225 return -ENODEV;
226 else if (msg->result != EC_RES_SUCCESS)
227 return msg->result;
228
229 return 0;
230}
231
232static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev)
233{
234 struct cros_ec_command *msg;
235 struct ec_params_hello *hello_params;
236 struct ec_response_hello *hello_response;
237 int ret;
238 int len = max(sizeof(*hello_params), sizeof(*hello_response));
239
240 msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
241 if (!msg)
242 return -ENOMEM;
243
244 msg->version = 0;
245 msg->command = EC_CMD_HELLO;
246 hello_params = (struct ec_params_hello *)msg->data;
247 msg->outsize = sizeof(*hello_params);
248 hello_response = (struct ec_response_hello *)msg->data;
249 msg->insize = sizeof(*hello_response);
250
251 hello_params->in_data = 0xa0b0c0d0;
252
253 ret = send_command(ec_dev, msg);
254
255 if (ret < 0) {
256 dev_dbg(ec_dev->dev,
257 "EC failed to respond to v2 hello: %d\n",
258 ret);
259 goto exit;
260 } else if (msg->result != EC_RES_SUCCESS) {
261 dev_err(ec_dev->dev,
262 "EC responded to v2 hello with error: %d\n",
263 msg->result);
264 ret = msg->result;
265 goto exit;
266 } else if (hello_response->out_data != 0xa1b2c3d4) {
267 dev_err(ec_dev->dev,
268 "EC responded to v2 hello with bad result: %u\n",
269 hello_response->out_data);
270 ret = -EBADMSG;
271 goto exit;
272 }
273
274 ret = 0;
275
276 exit:
277 kfree(msg);
278 return ret;
279}
280
281/*
282 * cros_ec_get_host_command_version_mask
283 *
284 * Get the version mask of a given command.
285 *
286 * @ec_dev: EC device to call
287 * @msg: message structure to use
288 * @cmd: command to get the version of.
289 * @mask: result when function returns 0.
290 *
291 * @return 0 on success, error code otherwise
292 *
293 * LOCKING:
294 * the caller has ec_dev->lock mutex or the caller knows there is
295 * no other command in progress.
296 */
297static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev,
298 u16 cmd, u32 *mask)
299{
300 struct ec_params_get_cmd_versions *pver;
301 struct ec_response_get_cmd_versions *rver;
302 struct cros_ec_command *msg;
303 int ret;
304
305 msg = kmalloc(sizeof(*msg) + max(sizeof(*rver), sizeof(*pver)),
306 GFP_KERNEL);
307 if (!msg)
308 return -ENOMEM;
309
310 msg->version = 0;
311 msg->command = EC_CMD_GET_CMD_VERSIONS;
312 msg->insize = sizeof(*rver);
313 msg->outsize = sizeof(*pver);
314
315 pver = (struct ec_params_get_cmd_versions *)msg->data;
316 pver->cmd = cmd;
317
318 ret = send_command(ec_dev, msg);
319 if (ret > 0) {
320 rver = (struct ec_response_get_cmd_versions *)msg->data;
321 *mask = rver->version_mask;
322 }
323
324 kfree(msg);
325
326 return ret;
327}
328
329int cros_ec_query_all(struct cros_ec_device *ec_dev)
330{
331 struct device *dev = ec_dev->dev;
332 struct cros_ec_command *proto_msg;
333 struct ec_response_get_protocol_info *proto_info;
334 u32 ver_mask = 0;
335 int ret;
336
337 proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info),
338 GFP_KERNEL);
339 if (!proto_msg)
340 return -ENOMEM;
341
342 /* First try sending with proto v3. */
343 ec_dev->proto_version = 3;
344 ret = cros_ec_host_command_proto_query(ec_dev, 0, proto_msg);
345
346 if (ret == 0) {
347 proto_info = (struct ec_response_get_protocol_info *)
348 proto_msg->data;
349 ec_dev->max_request = proto_info->max_request_packet_size -
350 sizeof(struct ec_host_request);
351 ec_dev->max_response = proto_info->max_response_packet_size -
352 sizeof(struct ec_host_response);
353 ec_dev->proto_version =
354 min(EC_HOST_REQUEST_VERSION,
355 fls(proto_info->protocol_versions) - 1);
356 dev_dbg(ec_dev->dev,
357 "using proto v%u\n",
358 ec_dev->proto_version);
359
360 ec_dev->din_size = ec_dev->max_response +
361 sizeof(struct ec_host_response) +
362 EC_MAX_RESPONSE_OVERHEAD;
363 ec_dev->dout_size = ec_dev->max_request +
364 sizeof(struct ec_host_request) +
365 EC_MAX_REQUEST_OVERHEAD;
366
367 /*
368 * Check for PD
369 */
370 ret = cros_ec_host_command_proto_query(ec_dev, 1, proto_msg);
371
372 if (ret) {
373 dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret);
374 ec_dev->max_passthru = 0;
375 } else {
376 dev_dbg(ec_dev->dev, "found PD chip\n");
377 ec_dev->max_passthru =
378 proto_info->max_request_packet_size -
379 sizeof(struct ec_host_request);
380 }
381 } else {
382 /* Try querying with a v2 hello message. */
383 ec_dev->proto_version = 2;
384 ret = cros_ec_host_command_proto_query_v2(ec_dev);
385
386 if (ret == 0) {
387 /* V2 hello succeeded. */
388 dev_dbg(ec_dev->dev, "falling back to proto v2\n");
389
390 ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE;
391 ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE;
392 ec_dev->max_passthru = 0;
393 ec_dev->pkt_xfer = NULL;
394 ec_dev->din_size = EC_PROTO2_MSG_BYTES;
395 ec_dev->dout_size = EC_PROTO2_MSG_BYTES;
396 } else {
397 /*
398 * It's possible for a test to occur too early when
399 * the EC isn't listening. If this happens, we'll
400 * test later when the first command is run.
401 */
402 ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN;
403 dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret);
404 goto exit;
405 }
406 }
407
408 devm_kfree(dev, ec_dev->din);
409 devm_kfree(dev, ec_dev->dout);
410
411 ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
412 if (!ec_dev->din) {
413 ret = -ENOMEM;
414 goto exit;
415 }
416
417 ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
418 if (!ec_dev->dout) {
419 devm_kfree(dev, ec_dev->din);
420 ret = -ENOMEM;
421 goto exit;
422 }
423
424 /* Probe if MKBP event is supported */
425 ret = cros_ec_get_host_command_version_mask(ec_dev,
426 EC_CMD_GET_NEXT_EVENT,
427 &ver_mask);
428 if (ret < 0 || ver_mask == 0)
429 ec_dev->mkbp_event_supported = 0;
430 else
431 ec_dev->mkbp_event_supported = 1;
432
433 /* Probe if host sleep v1 is supported for S0ix failure detection. */
434 ret = cros_ec_get_host_command_version_mask(ec_dev,
435 EC_CMD_HOST_SLEEP_EVENT,
436 &ver_mask);
437 ec_dev->host_sleep_v1 = (ret >= 0 && (ver_mask & EC_VER_MASK(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
450exit:
451 kfree(proto_msg);
452 return ret;
453}
454EXPORT_SYMBOL(cros_ec_query_all);
455
456int 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}
501EXPORT_SYMBOL(cros_ec_cmd_xfer);
502
503int 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}
518EXPORT_SYMBOL(cros_ec_cmd_xfer_status);
519
520static 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
540static 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
568static 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
587int 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}
629EXPORT_SYMBOL(cros_ec_get_next_event);
630
631u32 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}
649EXPORT_SYMBOL(cros_ec_get_host_event);