1 /*
2  * cros_ec_debugfs - debug logs for Chrome OS EC
3  *
4  * Copyright 2015 Google, Inc.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program. If not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #include <linux/circ_buf.h>
21 #include <linux/debugfs.h>
22 #include <linux/delay.h>
23 #include <linux/fs.h>
24 #include <linux/mfd/cros_ec.h>
25 #include <linux/mfd/cros_ec_commands.h>
26 #include <linux/mutex.h>
27 #include <linux/poll.h>
28 #include <linux/sched.h>
29 #include <linux/slab.h>
30 #include <linux/wait.h>
31 
32 #define LOG_SHIFT		14
33 #define LOG_SIZE		(1 << LOG_SHIFT)
34 #define LOG_POLL_SEC		10
35 
36 #define CIRC_ADD(idx, size, value)	(((idx) + (value)) & ((size) - 1))
37 
38 /* struct cros_ec_debugfs - ChromeOS EC debugging information
39  *
40  * @ec: EC device this debugfs information belongs to
41  * @dir: dentry for debugfs files
42  * @log_buffer: circular buffer for console log information
43  * @read_msg: preallocated EC command and buffer to read console log
44  * @log_mutex: mutex to protect circular buffer
45  * @log_wq: waitqueue for log readers
46  * @log_poll_work: recurring task to poll EC for new console log data
47  * @panicinfo_blob: panicinfo debugfs blob
48  */
49 struct cros_ec_debugfs {
50 	struct cros_ec_dev *ec;
51 	struct dentry *dir;
52 	/* EC log */
53 	struct circ_buf log_buffer;
54 	struct cros_ec_command *read_msg;
55 	struct mutex log_mutex;
56 	wait_queue_head_t log_wq;
57 	struct delayed_work log_poll_work;
58 	/* EC panicinfo */
59 	struct debugfs_blob_wrapper panicinfo_blob;
60 };
61 
62 /*
63  * We need to make sure that the EC log buffer on the UART is large enough,
64  * so that it is unlikely enough to overlow within LOG_POLL_SEC.
65  */
66 static void cros_ec_console_log_work(struct work_struct *__work)
67 {
68 	struct cros_ec_debugfs *debug_info =
69 		container_of(to_delayed_work(__work),
70 			     struct cros_ec_debugfs,
71 			     log_poll_work);
72 	struct cros_ec_dev *ec = debug_info->ec;
73 	struct circ_buf *cb = &debug_info->log_buffer;
74 	struct cros_ec_command snapshot_msg = {
75 		.command = EC_CMD_CONSOLE_SNAPSHOT + ec->cmd_offset,
76 	};
77 
78 	struct ec_params_console_read_v1 *read_params =
79 		(struct ec_params_console_read_v1 *)debug_info->read_msg->data;
80 	uint8_t *ec_buffer = (uint8_t *)debug_info->read_msg->data;
81 	int idx;
82 	int buf_space;
83 	int ret;
84 
85 	ret = cros_ec_cmd_xfer(ec->ec_dev, &snapshot_msg);
86 	if (ret < 0) {
87 		dev_err(ec->dev, "EC communication failed\n");
88 		goto resched;
89 	}
90 	if (snapshot_msg.result != EC_RES_SUCCESS) {
91 		dev_err(ec->dev, "EC failed to snapshot the console log\n");
92 		goto resched;
93 	}
94 
95 	/* Loop until we have read everything, or there's an error. */
96 	mutex_lock(&debug_info->log_mutex);
97 	buf_space = CIRC_SPACE(cb->head, cb->tail, LOG_SIZE);
98 
99 	while (1) {
100 		if (!buf_space) {
101 			dev_info_once(ec->dev,
102 				      "Some logs may have been dropped...\n");
103 			break;
104 		}
105 
106 		memset(read_params, '\0', sizeof(*read_params));
107 		read_params->subcmd = CONSOLE_READ_RECENT;
108 		ret = cros_ec_cmd_xfer(ec->ec_dev, debug_info->read_msg);
109 		if (ret < 0) {
110 			dev_err(ec->dev, "EC communication failed\n");
111 			break;
112 		}
113 		if (debug_info->read_msg->result != EC_RES_SUCCESS) {
114 			dev_err(ec->dev,
115 				"EC failed to read the console log\n");
116 			break;
117 		}
118 
119 		/* If the buffer is empty, we're done here. */
120 		if (ret == 0 || ec_buffer[0] == '\0')
121 			break;
122 
123 		idx = 0;
124 		while (idx < ret && ec_buffer[idx] != '\0' && buf_space > 0) {
125 			cb->buf[cb->head] = ec_buffer[idx];
126 			cb->head = CIRC_ADD(cb->head, LOG_SIZE, 1);
127 			idx++;
128 			buf_space--;
129 		}
130 
131 		wake_up(&debug_info->log_wq);
132 	}
133 
134 	mutex_unlock(&debug_info->log_mutex);
135 
136 resched:
137 	schedule_delayed_work(&debug_info->log_poll_work,
138 			      msecs_to_jiffies(LOG_POLL_SEC * 1000));
139 }
140 
141 static int cros_ec_console_log_open(struct inode *inode, struct file *file)
142 {
143 	file->private_data = inode->i_private;
144 
145 	return nonseekable_open(inode, file);
146 }
147 
148 static ssize_t cros_ec_console_log_read(struct file *file, char __user *buf,
149 					size_t count, loff_t *ppos)
150 {
151 	struct cros_ec_debugfs *debug_info = file->private_data;
152 	struct circ_buf *cb = &debug_info->log_buffer;
153 	ssize_t ret;
154 
155 	mutex_lock(&debug_info->log_mutex);
156 
157 	while (!CIRC_CNT(cb->head, cb->tail, LOG_SIZE)) {
158 		if (file->f_flags & O_NONBLOCK) {
159 			ret = -EAGAIN;
160 			goto error;
161 		}
162 
163 		mutex_unlock(&debug_info->log_mutex);
164 
165 		ret = wait_event_interruptible(debug_info->log_wq,
166 					CIRC_CNT(cb->head, cb->tail, LOG_SIZE));
167 		if (ret < 0)
168 			return ret;
169 
170 		mutex_lock(&debug_info->log_mutex);
171 	}
172 
173 	/* Only copy until the end of the circular buffer, and let userspace
174 	 * retry to get the rest of the data.
175 	 */
176 	ret = min_t(size_t, CIRC_CNT_TO_END(cb->head, cb->tail, LOG_SIZE),
177 		    count);
178 
179 	if (copy_to_user(buf, cb->buf + cb->tail, ret)) {
180 		ret = -EFAULT;
181 		goto error;
182 	}
183 
184 	cb->tail = CIRC_ADD(cb->tail, LOG_SIZE, ret);
185 
186 error:
187 	mutex_unlock(&debug_info->log_mutex);
188 	return ret;
189 }
190 
191 static __poll_t cros_ec_console_log_poll(struct file *file,
192 					     poll_table *wait)
193 {
194 	struct cros_ec_debugfs *debug_info = file->private_data;
195 	__poll_t mask = 0;
196 
197 	poll_wait(file, &debug_info->log_wq, wait);
198 
199 	mutex_lock(&debug_info->log_mutex);
200 	if (CIRC_CNT(debug_info->log_buffer.head,
201 		     debug_info->log_buffer.tail,
202 		     LOG_SIZE))
203 		mask |= EPOLLIN | EPOLLRDNORM;
204 	mutex_unlock(&debug_info->log_mutex);
205 
206 	return mask;
207 }
208 
209 static int cros_ec_console_log_release(struct inode *inode, struct file *file)
210 {
211 	return 0;
212 }
213 
214 static ssize_t cros_ec_pdinfo_read(struct file *file,
215 				   char __user *user_buf,
216 				   size_t count,
217 				   loff_t *ppos)
218 {
219 	char read_buf[EC_USB_PD_MAX_PORTS * 40], *p = read_buf;
220 	struct cros_ec_debugfs *debug_info = file->private_data;
221 	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
222 	struct {
223 		struct cros_ec_command msg;
224 		union {
225 			struct ec_response_usb_pd_control_v1 resp;
226 			struct ec_params_usb_pd_control params;
227 		};
228 	} __packed ec_buf;
229 	struct cros_ec_command *msg;
230 	struct ec_response_usb_pd_control_v1 *resp;
231 	struct ec_params_usb_pd_control *params;
232 	int i;
233 
234 	msg = &ec_buf.msg;
235 	params = (struct ec_params_usb_pd_control *)msg->data;
236 	resp = (struct ec_response_usb_pd_control_v1 *)msg->data;
237 
238 	msg->command = EC_CMD_USB_PD_CONTROL;
239 	msg->version = 1;
240 	msg->insize = sizeof(*resp);
241 	msg->outsize = sizeof(*params);
242 
243 	/*
244 	 * Read status from all PD ports until failure, typically caused
245 	 * by attempting to read status on a port that doesn't exist.
246 	 */
247 	for (i = 0; i < EC_USB_PD_MAX_PORTS; ++i) {
248 		params->port = i;
249 		params->role = 0;
250 		params->mux = 0;
251 		params->swap = 0;
252 
253 		if (cros_ec_cmd_xfer_status(ec_dev, msg) < 0)
254 			break;
255 
256 		p += scnprintf(p, sizeof(read_buf) + read_buf - p,
257 			       "p%d: %s en:%.2x role:%.2x pol:%.2x\n", i,
258 			       resp->state, resp->enabled, resp->role,
259 			       resp->polarity);
260 	}
261 
262 	return simple_read_from_buffer(user_buf, count, ppos,
263 				       read_buf, p - read_buf);
264 }
265 
266 const struct file_operations cros_ec_console_log_fops = {
267 	.owner = THIS_MODULE,
268 	.open = cros_ec_console_log_open,
269 	.read = cros_ec_console_log_read,
270 	.llseek = no_llseek,
271 	.poll = cros_ec_console_log_poll,
272 	.release = cros_ec_console_log_release,
273 };
274 
275 const struct file_operations cros_ec_pdinfo_fops = {
276 	.owner = THIS_MODULE,
277 	.open = simple_open,
278 	.read = cros_ec_pdinfo_read,
279 	.llseek = default_llseek,
280 };
281 
282 static int ec_read_version_supported(struct cros_ec_dev *ec)
283 {
284 	struct ec_params_get_cmd_versions_v1 *params;
285 	struct ec_response_get_cmd_versions *response;
286 	int ret;
287 
288 	struct cros_ec_command *msg;
289 
290 	msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
291 		GFP_KERNEL);
292 	if (!msg)
293 		return 0;
294 
295 	msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
296 	msg->outsize = sizeof(*params);
297 	msg->insize = sizeof(*response);
298 
299 	params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
300 	params->cmd = EC_CMD_CONSOLE_READ;
301 	response = (struct ec_response_get_cmd_versions *)msg->data;
302 
303 	ret = cros_ec_cmd_xfer(ec->ec_dev, msg) >= 0 &&
304 		msg->result == EC_RES_SUCCESS &&
305 		(response->version_mask & EC_VER_MASK(1));
306 
307 	kfree(msg);
308 
309 	return ret;
310 }
311 
312 static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
313 {
314 	struct cros_ec_dev *ec = debug_info->ec;
315 	char *buf;
316 	int read_params_size;
317 	int read_response_size;
318 
319 	if (!ec_read_version_supported(ec)) {
320 		dev_warn(ec->dev,
321 			"device does not support reading the console log\n");
322 		return 0;
323 	}
324 
325 	buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
326 	if (!buf)
327 		return -ENOMEM;
328 
329 	read_params_size = sizeof(struct ec_params_console_read_v1);
330 	read_response_size = ec->ec_dev->max_response;
331 	debug_info->read_msg = devm_kzalloc(ec->dev,
332 		sizeof(*debug_info->read_msg) +
333 			max(read_params_size, read_response_size), GFP_KERNEL);
334 	if (!debug_info->read_msg)
335 		return -ENOMEM;
336 
337 	debug_info->read_msg->version = 1;
338 	debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
339 	debug_info->read_msg->outsize = read_params_size;
340 	debug_info->read_msg->insize = read_response_size;
341 
342 	debug_info->log_buffer.buf = buf;
343 	debug_info->log_buffer.head = 0;
344 	debug_info->log_buffer.tail = 0;
345 
346 	mutex_init(&debug_info->log_mutex);
347 	init_waitqueue_head(&debug_info->log_wq);
348 
349 	if (!debugfs_create_file("console_log",
350 				 S_IFREG | 0444,
351 				 debug_info->dir,
352 				 debug_info,
353 				 &cros_ec_console_log_fops))
354 		return -ENOMEM;
355 
356 	INIT_DELAYED_WORK(&debug_info->log_poll_work,
357 			  cros_ec_console_log_work);
358 	schedule_delayed_work(&debug_info->log_poll_work, 0);
359 
360 	return 0;
361 }
362 
363 static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
364 {
365 	if (debug_info->log_buffer.buf) {
366 		cancel_delayed_work_sync(&debug_info->log_poll_work);
367 		mutex_destroy(&debug_info->log_mutex);
368 	}
369 }
370 
371 static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
372 {
373 	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
374 	int ret;
375 	struct cros_ec_command *msg;
376 	int insize;
377 
378 	insize = ec_dev->max_response;
379 
380 	msg = devm_kzalloc(debug_info->ec->dev,
381 			sizeof(*msg) + insize, GFP_KERNEL);
382 	if (!msg)
383 		return -ENOMEM;
384 
385 	msg->command = EC_CMD_GET_PANIC_INFO;
386 	msg->insize = insize;
387 
388 	ret = cros_ec_cmd_xfer(ec_dev, msg);
389 	if (ret < 0) {
390 		dev_warn(debug_info->ec->dev, "Cannot read panicinfo.\n");
391 		ret = 0;
392 		goto free;
393 	}
394 
395 	/* No panic data */
396 	if (ret == 0)
397 		goto free;
398 
399 	debug_info->panicinfo_blob.data = msg->data;
400 	debug_info->panicinfo_blob.size = ret;
401 
402 	if (!debugfs_create_blob("panicinfo",
403 				 S_IFREG | 0444,
404 				 debug_info->dir,
405 				 &debug_info->panicinfo_blob)) {
406 		ret = -ENOMEM;
407 		goto free;
408 	}
409 
410 	return 0;
411 
412 free:
413 	devm_kfree(debug_info->ec->dev, msg);
414 	return ret;
415 }
416 
417 static int cros_ec_create_pdinfo(struct cros_ec_debugfs *debug_info)
418 {
419 	if (!debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
420 				 &cros_ec_pdinfo_fops))
421 		return -ENOMEM;
422 
423 	return 0;
424 }
425 
426 int cros_ec_debugfs_init(struct cros_ec_dev *ec)
427 {
428 	struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
429 	const char *name = ec_platform->ec_name;
430 	struct cros_ec_debugfs *debug_info;
431 	int ret;
432 
433 	debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
434 	if (!debug_info)
435 		return -ENOMEM;
436 
437 	debug_info->ec = ec;
438 	debug_info->dir = debugfs_create_dir(name, NULL);
439 	if (!debug_info->dir)
440 		return -ENOMEM;
441 
442 	ret = cros_ec_create_panicinfo(debug_info);
443 	if (ret)
444 		goto remove_debugfs;
445 
446 	ret = cros_ec_create_console_log(debug_info);
447 	if (ret)
448 		goto remove_debugfs;
449 
450 	ret = cros_ec_create_pdinfo(debug_info);
451 	if (ret)
452 		goto remove_debugfs;
453 
454 	ec->debug_info = debug_info;
455 
456 	return 0;
457 
458 remove_debugfs:
459 	debugfs_remove_recursive(debug_info->dir);
460 	return ret;
461 }
462 EXPORT_SYMBOL(cros_ec_debugfs_init);
463 
464 void cros_ec_debugfs_remove(struct cros_ec_dev *ec)
465 {
466 	if (!ec->debug_info)
467 		return;
468 
469 	debugfs_remove_recursive(ec->debug_info->dir);
470 	cros_ec_cleanup_console_log(ec->debug_info);
471 }
472 EXPORT_SYMBOL(cros_ec_debugfs_remove);
473 
474 void cros_ec_debugfs_suspend(struct cros_ec_dev *ec)
475 {
476 	/*
477 	 * cros_ec_debugfs_init() failures are non-fatal; it's also possible
478 	 * that we initted things but decided that console log wasn't supported.
479 	 * We'll use the same set of checks that cros_ec_debugfs_remove() +
480 	 * cros_ec_cleanup_console_log() end up using to handle those cases.
481 	 */
482 	if (ec->debug_info && ec->debug_info->log_buffer.buf)
483 		cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
484 }
485 EXPORT_SYMBOL(cros_ec_debugfs_suspend);
486 
487 void cros_ec_debugfs_resume(struct cros_ec_dev *ec)
488 {
489 	if (ec->debug_info && ec->debug_info->log_buffer.buf)
490 		schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
491 }
492 EXPORT_SYMBOL(cros_ec_debugfs_resume);
493