?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[cris-mirror.git] / drivers / platform / chrome / cros_ec_proto.c
blobe7bbdf947bbcf93ce4acebbcecd13c17ff247d5c
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 < 0)
95 break;
96
97 msg->result = status_msg->result;
98 if (status_msg->result != EC_RES_SUCCESS)
99 break;
100
101 status = (struct ec_response_get_comms_status *)
102 status_msg->data;
103 if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
104 break;
105 }
106
107 kfree(status_msg);
108 }
109
110 return ret;
111 }
112
113 int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
114 struct cros_ec_command *msg)
115 {
116 u8 *out;
117 u8 csum;
118 int i;
119
120 if (ec_dev->proto_version > 2)
121 return prepare_packet(ec_dev, msg);
122
123 BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
124 out = ec_dev->dout;
125 out[0] = EC_CMD_VERSION0 + msg->version;
126 out[1] = msg->command;
127 out[2] = msg->outsize;
128 csum = out[0] + out[1] + out[2];
129 for (i = 0; i < msg->outsize; i++)
130 csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
131 out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum;
132
133 return EC_MSG_TX_PROTO_BYTES + msg->outsize;
134 }
135 EXPORT_SYMBOL(cros_ec_prepare_tx);
136
137 int cros_ec_check_result(struct cros_ec_device *ec_dev,
138 struct cros_ec_command *msg)
139 {
140 switch (msg->result) {
141 case EC_RES_SUCCESS:
142 return 0;
143 case EC_RES_IN_PROGRESS:
144 dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
145 msg->command);
146 return -EAGAIN;
147 default:
148 dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
149 msg->command, msg->result);
150 return 0;
151 }
152 }
153 EXPORT_SYMBOL(cros_ec_check_result);
154
155 /*
156 * cros_ec_get_host_event_wake_mask
157 *
158 * Get the mask of host events that cause wake from suspend.
159 *
160 * @ec_dev: EC device to call
161 * @msg: message structure to use
162 * @mask: result when function returns >=0.
163 *
164 * LOCKING:
165 * the caller has ec_dev->lock mutex, or the caller knows there is
166 * no other command in progress.
167 */
168 static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev,
169 struct cros_ec_command *msg,
170 uint32_t *mask)
171 {
172 struct ec_response_host_event_mask *r;
173 int ret;
174
175 msg->command = EC_CMD_HOST_EVENT_GET_WAKE_MASK;
176 msg->version = 0;
177 msg->outsize = 0;
178 msg->insize = sizeof(*r);
179
180 ret = send_command(ec_dev, msg);
181 if (ret > 0) {
182 r = (struct ec_response_host_event_mask *)msg->data;
183 *mask = r->mask;
184 }
185
186 return ret;
187 }
188
189 static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev,
190 int devidx,
191 struct cros_ec_command *msg)
192 {
193 /*
194 * Try using v3+ to query for supported protocols. If this
195 * command fails, fall back to v2. Returns the highest protocol
196 * supported by the EC.
197 * Also sets the max request/response/passthru size.
198 */
199 int ret;
200
201 if (!ec_dev->pkt_xfer)
202 return -EPROTONOSUPPORT;
203
204 memset(msg, 0, sizeof(*msg));
205 msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO;
206 msg->insize = sizeof(struct ec_response_get_protocol_info);
207
208 ret = send_command(ec_dev, msg);
209
210 if (ret < 0) {
211 dev_dbg(ec_dev->dev,
212 "failed to check for EC[%d] protocol version: %d\n",
213 devidx, ret);
214 return ret;
215 }
216
217 if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND)
218 return -ENODEV;
219 else if (msg->result != EC_RES_SUCCESS)
220 return msg->result;
221
222 return 0;
223 }
224
225 static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev)
226 {
227 struct cros_ec_command *msg;
228 struct ec_params_hello *hello_params;
229 struct ec_response_hello *hello_response;
230 int ret;
231 int len = max(sizeof(*hello_params), sizeof(*hello_response));
232
233 msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
234 if (!msg)
235 return -ENOMEM;
236
237 msg->version = 0;
238 msg->command = EC_CMD_HELLO;
239 hello_params = (struct ec_params_hello *)msg->data;
240 msg->outsize = sizeof(*hello_params);
241 hello_response = (struct ec_response_hello *)msg->data;
242 msg->insize = sizeof(*hello_response);
243
244 hello_params->in_data = 0xa0b0c0d0;
245
246 ret = send_command(ec_dev, msg);
247
248 if (ret < 0) {
249 dev_dbg(ec_dev->dev,
250 "EC failed to respond to v2 hello: %d\n",
251 ret);
252 goto exit;
253 } else if (msg->result != EC_RES_SUCCESS) {
254 dev_err(ec_dev->dev,
255 "EC responded to v2 hello with error: %d\n",
256 msg->result);
257 ret = msg->result;
258 goto exit;
259 } else if (hello_response->out_data != 0xa1b2c3d4) {
260 dev_err(ec_dev->dev,
261 "EC responded to v2 hello with bad result: %u\n",
262 hello_response->out_data);
263 ret = -EBADMSG;
264 goto exit;
265 }
266
267 ret = 0;
268
269 exit:
270 kfree(msg);
271 return ret;
272 }
273
274 /*
275 * cros_ec_get_host_command_version_mask
276 *
277 * Get the version mask of a given command.
278 *
279 * @ec_dev: EC device to call
280 * @msg: message structure to use
281 * @cmd: command to get the version of.
282 * @mask: result when function returns 0.
283 *
284 * @return 0 on success, error code otherwise
285 *
286 * LOCKING:
287 * the caller has ec_dev->lock mutex or the caller knows there is
288 * no other command in progress.
289 */
290 static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev,
291 u16 cmd, u32 *mask)
292 {
293 struct ec_params_get_cmd_versions *pver;
294 struct ec_response_get_cmd_versions *rver;
295 struct cros_ec_command *msg;
296 int ret;
297
298 msg = kmalloc(sizeof(*msg) + max(sizeof(*rver), sizeof(*pver)),
299 GFP_KERNEL);
300 if (!msg)
301 return -ENOMEM;
302
303 msg->version = 0;
304 msg->command = EC_CMD_GET_CMD_VERSIONS;
305 msg->insize = sizeof(*rver);
306 msg->outsize = sizeof(*pver);
307
308 pver = (struct ec_params_get_cmd_versions *)msg->data;
309 pver->cmd = cmd;
310
311 ret = send_command(ec_dev, msg);
312 if (ret > 0) {
313 rver = (struct ec_response_get_cmd_versions *)msg->data;
314 *mask = rver->version_mask;
315 }
316
317 kfree(msg);
318
319 return ret;
320 }
321
322 int cros_ec_query_all(struct cros_ec_device *ec_dev)
323 {
324 struct device *dev = ec_dev->dev;
325 struct cros_ec_command *proto_msg;
326 struct ec_response_get_protocol_info *proto_info;
327 u32 ver_mask = 0;
328 int ret;
329
330 proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info),
331 GFP_KERNEL);
332 if (!proto_msg)
333 return -ENOMEM;
334
335 /* First try sending with proto v3. */
336 ec_dev->proto_version = 3;
337 ret = cros_ec_host_command_proto_query(ec_dev, 0, proto_msg);
338
339 if (ret == 0) {
340 proto_info = (struct ec_response_get_protocol_info *)
341 proto_msg->data;
342 ec_dev->max_request = proto_info->max_request_packet_size -
343 sizeof(struct ec_host_request);
344 ec_dev->max_response = proto_info->max_response_packet_size -
345 sizeof(struct ec_host_response);
346 ec_dev->proto_version =
347 min(EC_HOST_REQUEST_VERSION,
348 fls(proto_info->protocol_versions) - 1);
349 dev_dbg(ec_dev->dev,
350 "using proto v%u\n",
351 ec_dev->proto_version);
352
353 ec_dev->din_size = ec_dev->max_response +
354 sizeof(struct ec_host_response) +
355 EC_MAX_RESPONSE_OVERHEAD;
356 ec_dev->dout_size = ec_dev->max_request +
357 sizeof(struct ec_host_request) +
358 EC_MAX_REQUEST_OVERHEAD;
359
360 /*
361 * Check for PD
362 */
363 ret = cros_ec_host_command_proto_query(ec_dev, 1, proto_msg);
364
365 if (ret) {
366 dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret);
367 ec_dev->max_passthru = 0;
368 } else {
369 dev_dbg(ec_dev->dev, "found PD chip\n");
370 ec_dev->max_passthru =
371 proto_info->max_request_packet_size -
372 sizeof(struct ec_host_request);
373 }
374 } else {
375 /* Try querying with a v2 hello message. */
376 ec_dev->proto_version = 2;
377 ret = cros_ec_host_command_proto_query_v2(ec_dev);
378
379 if (ret == 0) {
380 /* V2 hello succeeded. */
381 dev_dbg(ec_dev->dev, "falling back to proto v2\n");
382
383 ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE;
384 ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE;
385 ec_dev->max_passthru = 0;
386 ec_dev->pkt_xfer = NULL;
387 ec_dev->din_size = EC_PROTO2_MSG_BYTES;
388 ec_dev->dout_size = EC_PROTO2_MSG_BYTES;
389 } else {
390 /*
391 * It's possible for a test to occur too early when
392 * the EC isn't listening. If this happens, we'll
393 * test later when the first command is run.
394 */
395 ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN;
396 dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret);
397 goto exit;
398 }
399 }
400
401 devm_kfree(dev, ec_dev->din);
402 devm_kfree(dev, ec_dev->dout);
403
404 ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
405 if (!ec_dev->din) {
406 ret = -ENOMEM;
407 goto exit;
408 }
409
410 ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
411 if (!ec_dev->dout) {
412 devm_kfree(dev, ec_dev->din);
413 ret = -ENOMEM;
414 goto exit;
415 }
416
417 /* Probe if MKBP event is supported */
418 ret = cros_ec_get_host_command_version_mask(ec_dev,
419 EC_CMD_GET_NEXT_EVENT,
420 &ver_mask);
421 if (ret < 0 || ver_mask == 0)
422 ec_dev->mkbp_event_supported = 0;
423 else
424 ec_dev->mkbp_event_supported = 1;
425
426 /*
427 * Get host event wake mask, assume all events are wake events
428 * if unavailable.
429 */
430 ret = cros_ec_get_host_event_wake_mask(ec_dev, proto_msg,
431 &ec_dev->host_event_wake_mask);
432 if (ret < 0)
433 ec_dev->host_event_wake_mask = U32_MAX;
434
435 ret = 0;
436
437 exit:
438 kfree(proto_msg);
439 return ret;
440 }
441 EXPORT_SYMBOL(cros_ec_query_all);
442
443 int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
444 struct cros_ec_command *msg)
445 {
446 int ret;
447
448 mutex_lock(&ec_dev->lock);
449 if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) {
450 ret = cros_ec_query_all(ec_dev);
451 if (ret) {
452 dev_err(ec_dev->dev,
453 "EC version unknown and query failed; aborting command\n");
454 mutex_unlock(&ec_dev->lock);
455 return ret;
456 }
457 }
458
459 if (msg->insize > ec_dev->max_response) {
460 dev_dbg(ec_dev->dev, "clamping message receive buffer\n");
461 msg->insize = ec_dev->max_response;
462 }
463
464 if (msg->command < EC_CMD_PASSTHRU_OFFSET(1)) {
465 if (msg->outsize > ec_dev->max_request) {
466 dev_err(ec_dev->dev,
467 "request of size %u is too big (max: %u)\n",
468 msg->outsize,
469 ec_dev->max_request);
470 mutex_unlock(&ec_dev->lock);
471 return -EMSGSIZE;
472 }
473 } else {
474 if (msg->outsize > ec_dev->max_passthru) {
475 dev_err(ec_dev->dev,
476 "passthru rq of size %u is too big (max: %u)\n",
477 msg->outsize,
478 ec_dev->max_passthru);
479 mutex_unlock(&ec_dev->lock);
480 return -EMSGSIZE;
481 }
482 }
483 ret = send_command(ec_dev, msg);
484 mutex_unlock(&ec_dev->lock);
485
486 return ret;
487 }
488 EXPORT_SYMBOL(cros_ec_cmd_xfer);
489
490 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
491 struct cros_ec_command *msg)
492 {
493 int ret;
494
495 ret = cros_ec_cmd_xfer(ec_dev, msg);
496 if (ret < 0) {
497 dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
498 } else if (msg->result != EC_RES_SUCCESS) {
499 dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result);
500 return -EPROTO;
501 }
502
503 return ret;
504 }
505 EXPORT_SYMBOL(cros_ec_cmd_xfer_status);
506
507 static int get_next_event(struct cros_ec_device *ec_dev)
508 {
509 u8 buffer[sizeof(struct cros_ec_command) + sizeof(ec_dev->event_data)];
510 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
511 int ret;
512
513 if (ec_dev->suspended) {
514 dev_dbg(ec_dev->dev, "Device suspended.\n");
515 return -EHOSTDOWN;
516 }
517
518 msg->version = 0;
519 msg->command = EC_CMD_GET_NEXT_EVENT;
520 msg->insize = sizeof(ec_dev->event_data);
521 msg->outsize = 0;
522
523 ret = cros_ec_cmd_xfer(ec_dev, msg);
524 if (ret > 0) {
525 ec_dev->event_size = ret - 1;
526 memcpy(&ec_dev->event_data, msg->data,
527 sizeof(ec_dev->event_data));
528 }
529
530 return ret;
531 }
532
533 static int get_keyboard_state_event(struct cros_ec_device *ec_dev)
534 {
535 u8 buffer[sizeof(struct cros_ec_command) +
536 sizeof(ec_dev->event_data.data)];
537 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
538
539 msg->version = 0;
540 msg->command = EC_CMD_MKBP_STATE;
541 msg->insize = sizeof(ec_dev->event_data.data);
542 msg->outsize = 0;
543
544 ec_dev->event_size = cros_ec_cmd_xfer(ec_dev, msg);
545 ec_dev->event_data.event_type = EC_MKBP_EVENT_KEY_MATRIX;
546 memcpy(&ec_dev->event_data.data, msg->data,
547 sizeof(ec_dev->event_data.data));
548
549 return ec_dev->event_size;
550 }
551
552 int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event)
553 {
554 u32 host_event;
555 int ret;
556
557 if (!ec_dev->mkbp_event_supported) {
558 ret = get_keyboard_state_event(ec_dev);
559 if (ret < 0)
560 return ret;
561
562 if (wake_event)
563 *wake_event = true;
564
565 return ret;
566 }
567
568 ret = get_next_event(ec_dev);
569 if (ret < 0)
570 return ret;
571
572 if (wake_event) {
573 host_event = cros_ec_get_host_event(ec_dev);
574
575 /* Consider non-host_event as wake event */
576 *wake_event = !host_event ||
577 !!(host_event & ec_dev->host_event_wake_mask);
578 }
579
580 return ret;
581 }
582 EXPORT_SYMBOL(cros_ec_get_next_event);
583
584 u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev)
585 {
586 u32 host_event;
587
588 BUG_ON(!ec_dev->mkbp_event_supported);
589
590 if (ec_dev->event_data.event_type != EC_MKBP_EVENT_HOST_EVENT)
591 return 0;
592
593 if (ec_dev->event_size != sizeof(host_event)) {
594 dev_warn(ec_dev->dev, "Invalid host event size\n");
595 return 0;
596 }
597
598 host_event = get_unaligned_le32(&ec_dev->event_data.data.host_event);
599
600 return host_event;
601 }
602 EXPORT_SYMBOL(cros_ec_get_host_event);
CRIS linux kernel tree