?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
signal: Ensure generic siginfos the kernel sends have all bits initialized
[cris-mirror.git] / drivers / platform / chrome / cros_ec_proto.c
blob8dfa7fcb12488b6153cd2e770d297617243872d3
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
64 if (ec_dev->proto_version > 2)
65 ret = ec_dev->pkt_xfer(ec_dev, msg);
66 else
67 ret = ec_dev->cmd_xfer(ec_dev, msg);
68
69 if (msg->result == EC_RES_IN_PROGRESS) {
70 int i;
71 struct cros_ec_command *status_msg;
72 struct ec_response_get_comms_status *status;
73
74 status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
75 GFP_KERNEL);
76 if (!status_msg)
77 return -ENOMEM;
78
79 status_msg->version = 0;
80 status_msg->command = EC_CMD_GET_COMMS_STATUS;
81 status_msg->insize = sizeof(*status);
82 status_msg->outsize = 0;
83
84 /*
85 * Query the EC's status until it's no longer busy or
86 * we encounter an error.
87 */
88 for (i = 0; i < EC_COMMAND_RETRIES; i++) {
89 usleep_range(10000, 11000);
90
91 ret = ec_dev->cmd_xfer(ec_dev, status_msg);
92 if (ret < 0)
93 break;
94
95 msg->result = status_msg->result;
96 if (status_msg->result != EC_RES_SUCCESS)
97 break;
98
99 status = (struct ec_response_get_comms_status *)
100 status_msg->data;
101 if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
102 break;
103 }
104
105 kfree(status_msg);
106 }
107
108 return ret;
109 }
110
111 int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
112 struct cros_ec_command *msg)
113 {
114 u8 *out;
115 u8 csum;
116 int i;
117
118 if (ec_dev->proto_version > 2)
119 return prepare_packet(ec_dev, msg);
120
121 BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
122 out = ec_dev->dout;
123 out[0] = EC_CMD_VERSION0 + msg->version;
124 out[1] = msg->command;
125 out[2] = msg->outsize;
126 csum = out[0] + out[1] + out[2];
127 for (i = 0; i < msg->outsize; i++)
128 csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
129 out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum;
130
131 return EC_MSG_TX_PROTO_BYTES + msg->outsize;
132 }
133 EXPORT_SYMBOL(cros_ec_prepare_tx);
134
135 int cros_ec_check_result(struct cros_ec_device *ec_dev,
136 struct cros_ec_command *msg)
137 {
138 switch (msg->result) {
139 case EC_RES_SUCCESS:
140 return 0;
141 case EC_RES_IN_PROGRESS:
142 dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
143 msg->command);
144 return -EAGAIN;
145 default:
146 dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
147 msg->command, msg->result);
148 return 0;
149 }
150 }
151 EXPORT_SYMBOL(cros_ec_check_result);
152
153 /*
154 * cros_ec_get_host_event_wake_mask
155 *
156 * Get the mask of host events that cause wake from suspend.
157 *
158 * @ec_dev: EC device to call
159 * @msg: message structure to use
160 * @mask: result when function returns >=0.
161 *
162 * LOCKING:
163 * the caller has ec_dev->lock mutex, or the caller knows there is
164 * no other command in progress.
165 */
166 static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev,
167 struct cros_ec_command *msg,
168 uint32_t *mask)
169 {
170 struct ec_response_host_event_mask *r;
171 int ret;
172
173 msg->command = EC_CMD_HOST_EVENT_GET_WAKE_MASK;
174 msg->version = 0;
175 msg->outsize = 0;
176 msg->insize = sizeof(*r);
177
178 ret = send_command(ec_dev, msg);
179 if (ret > 0) {
180 r = (struct ec_response_host_event_mask *)msg->data;
181 *mask = r->mask;
182 }
183
184 return ret;
185 }
186
187 static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev,
188 int devidx,
189 struct cros_ec_command *msg)
190 {
191 /*
192 * Try using v3+ to query for supported protocols. If this
193 * command fails, fall back to v2. Returns the highest protocol
194 * supported by the EC.
195 * Also sets the max request/response/passthru size.
196 */
197 int ret;
198
199 if (!ec_dev->pkt_xfer)
200 return -EPROTONOSUPPORT;
201
202 memset(msg, 0, sizeof(*msg));
203 msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO;
204 msg->insize = sizeof(struct ec_response_get_protocol_info);
205
206 ret = send_command(ec_dev, msg);
207
208 if (ret < 0) {
209 dev_dbg(ec_dev->dev,
210 "failed to check for EC[%d] protocol version: %d\n",
211 devidx, ret);
212 return ret;
213 }
214
215 if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND)
216 return -ENODEV;
217 else if (msg->result != EC_RES_SUCCESS)
218 return msg->result;
219
220 return 0;
221 }
222
223 static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev)
224 {
225 struct cros_ec_command *msg;
226 struct ec_params_hello *hello_params;
227 struct ec_response_hello *hello_response;
228 int ret;
229 int len = max(sizeof(*hello_params), sizeof(*hello_response));
230
231 msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
232 if (!msg)
233 return -ENOMEM;
234
235 msg->version = 0;
236 msg->command = EC_CMD_HELLO;
237 hello_params = (struct ec_params_hello *)msg->data;
238 msg->outsize = sizeof(*hello_params);
239 hello_response = (struct ec_response_hello *)msg->data;
240 msg->insize = sizeof(*hello_response);
241
242 hello_params->in_data = 0xa0b0c0d0;
243
244 ret = send_command(ec_dev, msg);
245
246 if (ret < 0) {
247 dev_dbg(ec_dev->dev,
248 "EC failed to respond to v2 hello: %d\n",
249 ret);
250 goto exit;
251 } else if (msg->result != EC_RES_SUCCESS) {
252 dev_err(ec_dev->dev,
253 "EC responded to v2 hello with error: %d\n",
254 msg->result);
255 ret = msg->result;
256 goto exit;
257 } else if (hello_response->out_data != 0xa1b2c3d4) {
258 dev_err(ec_dev->dev,
259 "EC responded to v2 hello with bad result: %u\n",
260 hello_response->out_data);
261 ret = -EBADMSG;
262 goto exit;
263 }
264
265 ret = 0;
266
267 exit:
268 kfree(msg);
269 return ret;
270 }
271
272 /*
273 * cros_ec_get_host_command_version_mask
274 *
275 * Get the version mask of a given command.
276 *
277 * @ec_dev: EC device to call
278 * @msg: message structure to use
279 * @cmd: command to get the version of.
280 * @mask: result when function returns 0.
281 *
282 * @return 0 on success, error code otherwise
283 *
284 * LOCKING:
285 * the caller has ec_dev->lock mutex or the caller knows there is
286 * no other command in progress.
287 */
288 static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev,
289 u16 cmd, u32 *mask)
290 {
291 struct ec_params_get_cmd_versions *pver;
292 struct ec_response_get_cmd_versions *rver;
293 struct cros_ec_command *msg;
294 int ret;
295
296 msg = kmalloc(sizeof(*msg) + max(sizeof(*rver), sizeof(*pver)),
297 GFP_KERNEL);
298 if (!msg)
299 return -ENOMEM;
300
301 msg->version = 0;
302 msg->command = EC_CMD_GET_CMD_VERSIONS;
303 msg->insize = sizeof(*rver);
304 msg->outsize = sizeof(*pver);
305
306 pver = (struct ec_params_get_cmd_versions *)msg->data;
307 pver->cmd = cmd;
308
309 ret = send_command(ec_dev, msg);
310 if (ret > 0) {
311 rver = (struct ec_response_get_cmd_versions *)msg->data;
312 *mask = rver->version_mask;
313 }
314
315 kfree(msg);
316
317 return ret;
318 }
319
320 int cros_ec_query_all(struct cros_ec_device *ec_dev)
321 {
322 struct device *dev = ec_dev->dev;
323 struct cros_ec_command *proto_msg;
324 struct ec_response_get_protocol_info *proto_info;
325 u32 ver_mask = 0;
326 int ret;
327
328 proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info),
329 GFP_KERNEL);
330 if (!proto_msg)
331 return -ENOMEM;
332
333 /* First try sending with proto v3. */
334 ec_dev->proto_version = 3;
335 ret = cros_ec_host_command_proto_query(ec_dev, 0, proto_msg);
336
337 if (ret == 0) {
338 proto_info = (struct ec_response_get_protocol_info *)
339 proto_msg->data;
340 ec_dev->max_request = proto_info->max_request_packet_size -
341 sizeof(struct ec_host_request);
342 ec_dev->max_response = proto_info->max_response_packet_size -
343 sizeof(struct ec_host_response);
344 ec_dev->proto_version =
345 min(EC_HOST_REQUEST_VERSION,
346 fls(proto_info->protocol_versions) - 1);
347 dev_dbg(ec_dev->dev,
348 "using proto v%u\n",
349 ec_dev->proto_version);
350
351 ec_dev->din_size = ec_dev->max_response +
352 sizeof(struct ec_host_response) +
353 EC_MAX_RESPONSE_OVERHEAD;
354 ec_dev->dout_size = ec_dev->max_request +
355 sizeof(struct ec_host_request) +
356 EC_MAX_REQUEST_OVERHEAD;
357
358 /*
359 * Check for PD
360 */
361 ret = cros_ec_host_command_proto_query(ec_dev, 1, proto_msg);
362
363 if (ret) {
364 dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret);
365 ec_dev->max_passthru = 0;
366 } else {
367 dev_dbg(ec_dev->dev, "found PD chip\n");
368 ec_dev->max_passthru =
369 proto_info->max_request_packet_size -
370 sizeof(struct ec_host_request);
371 }
372 } else {
373 /* Try querying with a v2 hello message. */
374 ec_dev->proto_version = 2;
375 ret = cros_ec_host_command_proto_query_v2(ec_dev);
376
377 if (ret == 0) {
378 /* V2 hello succeeded. */
379 dev_dbg(ec_dev->dev, "falling back to proto v2\n");
380
381 ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE;
382 ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE;
383 ec_dev->max_passthru = 0;
384 ec_dev->pkt_xfer = NULL;
385 ec_dev->din_size = EC_PROTO2_MSG_BYTES;
386 ec_dev->dout_size = EC_PROTO2_MSG_BYTES;
387 } else {
388 /*
389 * It's possible for a test to occur too early when
390 * the EC isn't listening. If this happens, we'll
391 * test later when the first command is run.
392 */
393 ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN;
394 dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret);
395 goto exit;
396 }
397 }
398
399 devm_kfree(dev, ec_dev->din);
400 devm_kfree(dev, ec_dev->dout);
401
402 ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
403 if (!ec_dev->din) {
404 ret = -ENOMEM;
405 goto exit;
406 }
407
408 ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
409 if (!ec_dev->dout) {
410 devm_kfree(dev, ec_dev->din);
411 ret = -ENOMEM;
412 goto exit;
413 }
414
415 /* Probe if MKBP event is supported */
416 ret = cros_ec_get_host_command_version_mask(ec_dev,
417 EC_CMD_GET_NEXT_EVENT,
418 &ver_mask);
419 if (ret < 0 || ver_mask == 0)
420 ec_dev->mkbp_event_supported = 0;
421 else
422 ec_dev->mkbp_event_supported = 1;
423
424 /*
425 * Get host event wake mask, assume all events are wake events
426 * if unavailable.
427 */
428 ret = cros_ec_get_host_event_wake_mask(ec_dev, proto_msg,
429 &ec_dev->host_event_wake_mask);
430 if (ret < 0)
431 ec_dev->host_event_wake_mask = U32_MAX;
432
433 ret = 0;
434
435 exit:
436 kfree(proto_msg);
437 return ret;
438 }
439 EXPORT_SYMBOL(cros_ec_query_all);
440
441 int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
442 struct cros_ec_command *msg)
443 {
444 int ret;
445
446 mutex_lock(&ec_dev->lock);
447 if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) {
448 ret = cros_ec_query_all(ec_dev);
449 if (ret) {
450 dev_err(ec_dev->dev,
451 "EC version unknown and query failed; aborting command\n");
452 mutex_unlock(&ec_dev->lock);
453 return ret;
454 }
455 }
456
457 if (msg->insize > ec_dev->max_response) {
458 dev_dbg(ec_dev->dev, "clamping message receive buffer\n");
459 msg->insize = ec_dev->max_response;
460 }
461
462 if (msg->command < EC_CMD_PASSTHRU_OFFSET(1)) {
463 if (msg->outsize > ec_dev->max_request) {
464 dev_err(ec_dev->dev,
465 "request of size %u is too big (max: %u)\n",
466 msg->outsize,
467 ec_dev->max_request);
468 mutex_unlock(&ec_dev->lock);
469 return -EMSGSIZE;
470 }
471 } else {
472 if (msg->outsize > ec_dev->max_passthru) {
473 dev_err(ec_dev->dev,
474 "passthru rq of size %u is too big (max: %u)\n",
475 msg->outsize,
476 ec_dev->max_passthru);
477 mutex_unlock(&ec_dev->lock);
478 return -EMSGSIZE;
479 }
480 }
481 ret = send_command(ec_dev, msg);
482 mutex_unlock(&ec_dev->lock);
483
484 return ret;
485 }
486 EXPORT_SYMBOL(cros_ec_cmd_xfer);
487
488 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
489 struct cros_ec_command *msg)
490 {
491 int ret;
492
493 ret = cros_ec_cmd_xfer(ec_dev, msg);
494 if (ret < 0) {
495 dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
496 } else if (msg->result != EC_RES_SUCCESS) {
497 dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result);
498 return -EPROTO;
499 }
500
501 return ret;
502 }
503 EXPORT_SYMBOL(cros_ec_cmd_xfer_status);
504
505 static int get_next_event(struct cros_ec_device *ec_dev)
506 {
507 u8 buffer[sizeof(struct cros_ec_command) + sizeof(ec_dev->event_data)];
508 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
509 int ret;
510
511 if (ec_dev->suspended) {
512 dev_dbg(ec_dev->dev, "Device suspended.\n");
513 return -EHOSTDOWN;
514 }
515
516 msg->version = 0;
517 msg->command = EC_CMD_GET_NEXT_EVENT;
518 msg->insize = sizeof(ec_dev->event_data);
519 msg->outsize = 0;
520
521 ret = cros_ec_cmd_xfer(ec_dev, msg);
522 if (ret > 0) {
523 ec_dev->event_size = ret - 1;
524 memcpy(&ec_dev->event_data, msg->data,
525 sizeof(ec_dev->event_data));
526 }
527
528 return ret;
529 }
530
531 static int get_keyboard_state_event(struct cros_ec_device *ec_dev)
532 {
533 u8 buffer[sizeof(struct cros_ec_command) +
534 sizeof(ec_dev->event_data.data)];
535 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
536
537 msg->version = 0;
538 msg->command = EC_CMD_MKBP_STATE;
539 msg->insize = sizeof(ec_dev->event_data.data);
540 msg->outsize = 0;
541
542 ec_dev->event_size = cros_ec_cmd_xfer(ec_dev, msg);
543 ec_dev->event_data.event_type = EC_MKBP_EVENT_KEY_MATRIX;
544 memcpy(&ec_dev->event_data.data, msg->data,
545 sizeof(ec_dev->event_data.data));
546
547 return ec_dev->event_size;
548 }
549
550 int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event)
551 {
552 u32 host_event;
553 int ret;
554
555 if (!ec_dev->mkbp_event_supported) {
556 ret = get_keyboard_state_event(ec_dev);
557 if (ret < 0)
558 return ret;
559
560 if (wake_event)
561 *wake_event = true;
562
563 return ret;
564 }
565
566 ret = get_next_event(ec_dev);
567 if (ret < 0)
568 return ret;
569
570 if (wake_event) {
571 host_event = cros_ec_get_host_event(ec_dev);
572
573 /* Consider non-host_event as wake event */
574 *wake_event = !host_event ||
575 !!(host_event & ec_dev->host_event_wake_mask);
576 }
577
578 return ret;
579 }
580 EXPORT_SYMBOL(cros_ec_get_next_event);
581
582 u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev)
583 {
584 u32 host_event;
585
586 BUG_ON(!ec_dev->mkbp_event_supported);
587
588 if (ec_dev->event_data.event_type != EC_MKBP_EVENT_HOST_EVENT)
589 return 0;
590
591 if (ec_dev->event_size != sizeof(host_event)) {
592 dev_warn(ec_dev->dev, "Invalid host event size\n");
593 return 0;
594 }
595
596 host_event = get_unaligned_le32(&ec_dev->event_data.data.host_event);
597
598 return host_event;
599 }
600 EXPORT_SYMBOL(cros_ec_get_host_event);
CRIS linux kernel tree