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proc: test /proc/thread-self symlink
[linux/fpc-iii.git] / drivers / platform / chrome / cros_ec_proto.c
blob398393ab5df854d71d2158cad47b52923246bcb4
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 ret = (*xfer_fxn)(ec_dev, msg);
71 if (msg->result == EC_RES_IN_PROGRESS) {
72 int i;
73 struct cros_ec_command *status_msg;
74 struct ec_response_get_comms_status *status;
75
76 status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
77 GFP_KERNEL);
78 if (!status_msg)
79 return -ENOMEM;
80
81 status_msg->version = 0;
82 status_msg->command = EC_CMD_GET_COMMS_STATUS;
83 status_msg->insize = sizeof(*status);
84 status_msg->outsize = 0;
85
86 /*
87 * Query the EC's status until it's no longer busy or
88 * we encounter an error.
89 */
90 for (i = 0; i < EC_COMMAND_RETRIES; i++) {
91 usleep_range(10000, 11000);
92
93 ret = (*xfer_fxn)(ec_dev, status_msg);
94 if (ret == -EAGAIN)
95 continue;
96 if (ret < 0)
97 break;
98
99 msg->result = status_msg->result;
100 if (status_msg->result != EC_RES_SUCCESS)
101 break;
102
103 status = (struct ec_response_get_comms_status *)
104 status_msg->data;
105 if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
106 break;
107 }
108
109 kfree(status_msg);
110 }
111
112 return ret;
113 }
114
115 int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
116 struct cros_ec_command *msg)
117 {
118 u8 *out;
119 u8 csum;
120 int i;
121
122 if (ec_dev->proto_version > 2)
123 return prepare_packet(ec_dev, msg);
124
125 BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
126 out = ec_dev->dout;
127 out[0] = EC_CMD_VERSION0 + msg->version;
128 out[1] = msg->command;
129 out[2] = msg->outsize;
130 csum = out[0] + out[1] + out[2];
131 for (i = 0; i < msg->outsize; i++)
132 csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
133 out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum;
134
135 return EC_MSG_TX_PROTO_BYTES + msg->outsize;
136 }
137 EXPORT_SYMBOL(cros_ec_prepare_tx);
138
139 int cros_ec_check_result(struct cros_ec_device *ec_dev,
140 struct cros_ec_command *msg)
141 {
142 switch (msg->result) {
143 case EC_RES_SUCCESS:
144 return 0;
145 case EC_RES_IN_PROGRESS:
146 dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
147 msg->command);
148 return -EAGAIN;
149 default:
150 dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
151 msg->command, msg->result);
152 return 0;
153 }
154 }
155 EXPORT_SYMBOL(cros_ec_check_result);
156
157 /*
158 * cros_ec_get_host_event_wake_mask
159 *
160 * Get the mask of host events that cause wake from suspend.
161 *
162 * @ec_dev: EC device to call
163 * @msg: message structure to use
164 * @mask: result when function returns >=0.
165 *
166 * LOCKING:
167 * the caller has ec_dev->lock mutex, or the caller knows there is
168 * no other command in progress.
169 */
170 static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev,
171 struct cros_ec_command *msg,
172 uint32_t *mask)
173 {
174 struct ec_response_host_event_mask *r;
175 int ret;
176
177 msg->command = EC_CMD_HOST_EVENT_GET_WAKE_MASK;
178 msg->version = 0;
179 msg->outsize = 0;
180 msg->insize = sizeof(*r);
181
182 ret = send_command(ec_dev, msg);
183 if (ret > 0) {
184 r = (struct ec_response_host_event_mask *)msg->data;
185 *mask = r->mask;
186 }
187
188 return ret;
189 }
190
191 static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev,
192 int devidx,
193 struct cros_ec_command *msg)
194 {
195 /*
196 * Try using v3+ to query for supported protocols. If this
197 * command fails, fall back to v2. Returns the highest protocol
198 * supported by the EC.
199 * Also sets the max request/response/passthru size.
200 */
201 int ret;
202
203 if (!ec_dev->pkt_xfer)
204 return -EPROTONOSUPPORT;
205
206 memset(msg, 0, sizeof(*msg));
207 msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO;
208 msg->insize = sizeof(struct ec_response_get_protocol_info);
209
210 ret = send_command(ec_dev, msg);
211
212 if (ret < 0) {
213 dev_dbg(ec_dev->dev,
214 "failed to check for EC[%d] protocol version: %d\n",
215 devidx, ret);
216 return ret;
217 }
218
219 if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND)
220 return -ENODEV;
221 else if (msg->result != EC_RES_SUCCESS)
222 return msg->result;
223
224 return 0;
225 }
226
227 static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev)
228 {
229 struct cros_ec_command *msg;
230 struct ec_params_hello *hello_params;
231 struct ec_response_hello *hello_response;
232 int ret;
233 int len = max(sizeof(*hello_params), sizeof(*hello_response));
234
235 msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
236 if (!msg)
237 return -ENOMEM;
238
239 msg->version = 0;
240 msg->command = EC_CMD_HELLO;
241 hello_params = (struct ec_params_hello *)msg->data;
242 msg->outsize = sizeof(*hello_params);
243 hello_response = (struct ec_response_hello *)msg->data;
244 msg->insize = sizeof(*hello_response);
245
246 hello_params->in_data = 0xa0b0c0d0;
247
248 ret = send_command(ec_dev, msg);
249
250 if (ret < 0) {
251 dev_dbg(ec_dev->dev,
252 "EC failed to respond to v2 hello: %d\n",
253 ret);
254 goto exit;
255 } else if (msg->result != EC_RES_SUCCESS) {
256 dev_err(ec_dev->dev,
257 "EC responded to v2 hello with error: %d\n",
258 msg->result);
259 ret = msg->result;
260 goto exit;
261 } else if (hello_response->out_data != 0xa1b2c3d4) {
262 dev_err(ec_dev->dev,
263 "EC responded to v2 hello with bad result: %u\n",
264 hello_response->out_data);
265 ret = -EBADMSG;
266 goto exit;
267 }
268
269 ret = 0;
270
271 exit:
272 kfree(msg);
273 return ret;
274 }
275
276 /*
277 * cros_ec_get_host_command_version_mask
278 *
279 * Get the version mask of a given command.
280 *
281 * @ec_dev: EC device to call
282 * @msg: message structure to use
283 * @cmd: command to get the version of.
284 * @mask: result when function returns 0.
285 *
286 * @return 0 on success, error code otherwise
287 *
288 * LOCKING:
289 * the caller has ec_dev->lock mutex or the caller knows there is
290 * no other command in progress.
291 */
292 static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev,
293 u16 cmd, u32 *mask)
294 {
295 struct ec_params_get_cmd_versions *pver;
296 struct ec_response_get_cmd_versions *rver;
297 struct cros_ec_command *msg;
298 int ret;
299
300 msg = kmalloc(sizeof(*msg) + max(sizeof(*rver), sizeof(*pver)),
301 GFP_KERNEL);
302 if (!msg)
303 return -ENOMEM;
304
305 msg->version = 0;
306 msg->command = EC_CMD_GET_CMD_VERSIONS;
307 msg->insize = sizeof(*rver);
308 msg->outsize = sizeof(*pver);
309
310 pver = (struct ec_params_get_cmd_versions *)msg->data;
311 pver->cmd = cmd;
312
313 ret = send_command(ec_dev, msg);
314 if (ret > 0) {
315 rver = (struct ec_response_get_cmd_versions *)msg->data;
316 *mask = rver->version_mask;
317 }
318
319 kfree(msg);
320
321 return ret;
322 }
323
324 int cros_ec_query_all(struct cros_ec_device *ec_dev)
325 {
326 struct device *dev = ec_dev->dev;
327 struct cros_ec_command *proto_msg;
328 struct ec_response_get_protocol_info *proto_info;
329 u32 ver_mask = 0;
330 int ret;
331
332 proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info),
333 GFP_KERNEL);
334 if (!proto_msg)
335 return -ENOMEM;
336
337 /* First try sending with proto v3. */
338 ec_dev->proto_version = 3;
339 ret = cros_ec_host_command_proto_query(ec_dev, 0, proto_msg);
340
341 if (ret == 0) {
342 proto_info = (struct ec_response_get_protocol_info *)
343 proto_msg->data;
344 ec_dev->max_request = proto_info->max_request_packet_size -
345 sizeof(struct ec_host_request);
346 ec_dev->max_response = proto_info->max_response_packet_size -
347 sizeof(struct ec_host_response);
348 ec_dev->proto_version =
349 min(EC_HOST_REQUEST_VERSION,
350 fls(proto_info->protocol_versions) - 1);
351 dev_dbg(ec_dev->dev,
352 "using proto v%u\n",
353 ec_dev->proto_version);
354
355 ec_dev->din_size = ec_dev->max_response +
356 sizeof(struct ec_host_response) +
357 EC_MAX_RESPONSE_OVERHEAD;
358 ec_dev->dout_size = ec_dev->max_request +
359 sizeof(struct ec_host_request) +
360 EC_MAX_REQUEST_OVERHEAD;
361
362 /*
363 * Check for PD
364 */
365 ret = cros_ec_host_command_proto_query(ec_dev, 1, proto_msg);
366
367 if (ret) {
368 dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret);
369 ec_dev->max_passthru = 0;
370 } else {
371 dev_dbg(ec_dev->dev, "found PD chip\n");
372 ec_dev->max_passthru =
373 proto_info->max_request_packet_size -
374 sizeof(struct ec_host_request);
375 }
376 } else {
377 /* Try querying with a v2 hello message. */
378 ec_dev->proto_version = 2;
379 ret = cros_ec_host_command_proto_query_v2(ec_dev);
380
381 if (ret == 0) {
382 /* V2 hello succeeded. */
383 dev_dbg(ec_dev->dev, "falling back to proto v2\n");
384
385 ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE;
386 ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE;
387 ec_dev->max_passthru = 0;
388 ec_dev->pkt_xfer = NULL;
389 ec_dev->din_size = EC_PROTO2_MSG_BYTES;
390 ec_dev->dout_size = EC_PROTO2_MSG_BYTES;
391 } else {
392 /*
393 * It's possible for a test to occur too early when
394 * the EC isn't listening. If this happens, we'll
395 * test later when the first command is run.
396 */
397 ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN;
398 dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret);
399 goto exit;
400 }
401 }
402
403 devm_kfree(dev, ec_dev->din);
404 devm_kfree(dev, ec_dev->dout);
405
406 ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
407 if (!ec_dev->din) {
408 ret = -ENOMEM;
409 goto exit;
410 }
411
412 ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
413 if (!ec_dev->dout) {
414 devm_kfree(dev, ec_dev->din);
415 ret = -ENOMEM;
416 goto exit;
417 }
418
419 /* Probe if MKBP event is supported */
420 ret = cros_ec_get_host_command_version_mask(ec_dev,
421 EC_CMD_GET_NEXT_EVENT,
422 &ver_mask);
423 if (ret < 0 || ver_mask == 0)
424 ec_dev->mkbp_event_supported = 0;
425 else
426 ec_dev->mkbp_event_supported = 1;
427
428 /*
429 * Get host event wake mask, assume all events are wake events
430 * if unavailable.
431 */
432 ret = cros_ec_get_host_event_wake_mask(ec_dev, proto_msg,
433 &ec_dev->host_event_wake_mask);
434 if (ret < 0)
435 ec_dev->host_event_wake_mask = U32_MAX;
436
437 ret = 0;
438
439 exit:
440 kfree(proto_msg);
441 return ret;
442 }
443 EXPORT_SYMBOL(cros_ec_query_all);
444
445 int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
446 struct cros_ec_command *msg)
447 {
448 int ret;
449
450 mutex_lock(&ec_dev->lock);
451 if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) {
452 ret = cros_ec_query_all(ec_dev);
453 if (ret) {
454 dev_err(ec_dev->dev,
455 "EC version unknown and query failed; aborting command\n");
456 mutex_unlock(&ec_dev->lock);
457 return ret;
458 }
459 }
460
461 if (msg->insize > ec_dev->max_response) {
462 dev_dbg(ec_dev->dev, "clamping message receive buffer\n");
463 msg->insize = ec_dev->max_response;
464 }
465
466 if (msg->command < EC_CMD_PASSTHRU_OFFSET(1)) {
467 if (msg->outsize > ec_dev->max_request) {
468 dev_err(ec_dev->dev,
469 "request of size %u is too big (max: %u)\n",
470 msg->outsize,
471 ec_dev->max_request);
472 mutex_unlock(&ec_dev->lock);
473 return -EMSGSIZE;
474 }
475 } else {
476 if (msg->outsize > ec_dev->max_passthru) {
477 dev_err(ec_dev->dev,
478 "passthru rq of size %u is too big (max: %u)\n",
479 msg->outsize,
480 ec_dev->max_passthru);
481 mutex_unlock(&ec_dev->lock);
482 return -EMSGSIZE;
483 }
484 }
485 ret = send_command(ec_dev, msg);
486 mutex_unlock(&ec_dev->lock);
487
488 return ret;
489 }
490 EXPORT_SYMBOL(cros_ec_cmd_xfer);
491
492 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
493 struct cros_ec_command *msg)
494 {
495 int ret;
496
497 ret = cros_ec_cmd_xfer(ec_dev, msg);
498 if (ret < 0) {
499 dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
500 } else if (msg->result != EC_RES_SUCCESS) {
501 dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result);
502 return -EPROTO;
503 }
504
505 return ret;
506 }
507 EXPORT_SYMBOL(cros_ec_cmd_xfer_status);
508
509 static int get_next_event_xfer(struct cros_ec_device *ec_dev,
510 struct cros_ec_command *msg,
511 int version, uint32_t size)
512 {
513 int ret;
514
515 msg->version = version;
516 msg->command = EC_CMD_GET_NEXT_EVENT;
517 msg->insize = size;
518 msg->outsize = 0;
519
520 ret = cros_ec_cmd_xfer(ec_dev, msg);
521 if (ret > 0) {
522 ec_dev->event_size = ret - 1;
523 memcpy(&ec_dev->event_data, msg->data, ec_dev->event_size);
524 }
525
526 return ret;
527 }
528
529 static int get_next_event(struct cros_ec_device *ec_dev)
530 {
531 u8 buffer[sizeof(struct cros_ec_command) + sizeof(ec_dev->event_data)];
532 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
533 static int cmd_version = 1;
534 int ret;
535
536 if (ec_dev->suspended) {
537 dev_dbg(ec_dev->dev, "Device suspended.\n");
538 return -EHOSTDOWN;
539 }
540
541 if (cmd_version == 1) {
542 ret = get_next_event_xfer(ec_dev, msg, cmd_version,
543 sizeof(struct ec_response_get_next_event_v1));
544 if (ret < 0 || msg->result != EC_RES_INVALID_VERSION)
545 return ret;
546
547 /* Fallback to version 0 for future send attempts */
548 cmd_version = 0;
549 }
550
551 ret = get_next_event_xfer(ec_dev, msg, cmd_version,
552 sizeof(struct ec_response_get_next_event));
553
554 return ret;
555 }
556
557 static int get_keyboard_state_event(struct cros_ec_device *ec_dev)
558 {
559 u8 buffer[sizeof(struct cros_ec_command) +
560 sizeof(ec_dev->event_data.data)];
561 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
562
563 msg->version = 0;
564 msg->command = EC_CMD_MKBP_STATE;
565 msg->insize = sizeof(ec_dev->event_data.data);
566 msg->outsize = 0;
567
568 ec_dev->event_size = cros_ec_cmd_xfer(ec_dev, msg);
569 ec_dev->event_data.event_type = EC_MKBP_EVENT_KEY_MATRIX;
570 memcpy(&ec_dev->event_data.data, msg->data,
571 sizeof(ec_dev->event_data.data));
572
573 return ec_dev->event_size;
574 }
575
576 int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event)
577 {
578 u32 host_event;
579 int ret;
580
581 if (!ec_dev->mkbp_event_supported) {
582 ret = get_keyboard_state_event(ec_dev);
583 if (ret < 0)
584 return ret;
585
586 if (wake_event)
587 *wake_event = true;
588
589 return ret;
590 }
591
592 ret = get_next_event(ec_dev);
593 if (ret < 0)
594 return ret;
595
596 if (wake_event) {
597 host_event = cros_ec_get_host_event(ec_dev);
598
599 /* Consider non-host_event as wake event */
600 *wake_event = !host_event ||
601 !!(host_event & ec_dev->host_event_wake_mask);
602 }
603
604 return ret;
605 }
606 EXPORT_SYMBOL(cros_ec_get_next_event);
607
608 u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev)
609 {
610 u32 host_event;
611
612 BUG_ON(!ec_dev->mkbp_event_supported);
613
614 if (ec_dev->event_data.event_type != EC_MKBP_EVENT_HOST_EVENT)
615 return 0;
616
617 if (ec_dev->event_size != sizeof(host_event)) {
618 dev_warn(ec_dev->dev, "Invalid host event size\n");
619 return 0;
620 }
621
622 host_event = get_unaligned_le32(&ec_dev->event_data.data.host_event);
623
624 return host_event;
625 }
626 EXPORT_SYMBOL(cros_ec_get_host_event);
Linux with added FPC-III support