1 // SPDX-License-Identifier: GPL-2.0+
2 // Debug logs for the ChromeOS EC
3 //
4 // Copyright (C) 2015 Google, Inc.
5 
6 #include <linux/circ_buf.h>
7 #include <linux/debugfs.h>
8 #include <linux/delay.h>
9 #include <linux/fs.h>
10 #include <linux/module.h>
11 #include <linux/mutex.h>
12 #include <linux/platform_data/cros_ec_commands.h>
13 #include <linux/platform_data/cros_ec_proto.h>
14 #include <linux/platform_device.h>
15 #include <linux/poll.h>
16 #include <linux/sched.h>
17 #include <linux/slab.h>
18 #include <linux/wait.h>
19 
20 #define DRV_NAME "cros-ec-debugfs"
21 
22 #define LOG_SHIFT		14
23 #define LOG_SIZE		(1 << LOG_SHIFT)
24 #define LOG_POLL_SEC		10
25 
26 #define CIRC_ADD(idx, size, value)	(((idx) + (value)) & ((size) - 1))
27 
28 /* waitqueue for log readers */
29 static DECLARE_WAIT_QUEUE_HEAD(cros_ec_debugfs_log_wq);
30 
31 /**
32  * struct cros_ec_debugfs - EC debugging information.
33  *
34  * @ec: EC device this debugfs information belongs to
35  * @dir: dentry for debugfs files
36  * @log_buffer: circular buffer for console log information
37  * @read_msg: preallocated EC command and buffer to read console log
38  * @log_mutex: mutex to protect circular buffer
39  * @log_poll_work: recurring task to poll EC for new console log data
40  * @panicinfo_blob: panicinfo debugfs blob
41  */
42 struct cros_ec_debugfs {
43 	struct cros_ec_dev *ec;
44 	struct dentry *dir;
45 	/* EC log */
46 	struct circ_buf log_buffer;
47 	struct cros_ec_command *read_msg;
48 	struct mutex log_mutex;
49 	struct delayed_work log_poll_work;
50 	/* EC panicinfo */
51 	struct debugfs_blob_wrapper panicinfo_blob;
52 };
53 
54 /*
55  * We need to make sure that the EC log buffer on the UART is large enough,
56  * so that it is unlikely enough to overlow within LOG_POLL_SEC.
57  */
58 static void cros_ec_console_log_work(struct work_struct *__work)
59 {
60 	struct cros_ec_debugfs *debug_info =
61 		container_of(to_delayed_work(__work),
62 			     struct cros_ec_debugfs,
63 			     log_poll_work);
64 	struct cros_ec_dev *ec = debug_info->ec;
65 	struct circ_buf *cb = &debug_info->log_buffer;
66 	struct cros_ec_command snapshot_msg = {
67 		.command = EC_CMD_CONSOLE_SNAPSHOT + ec->cmd_offset,
68 	};
69 
70 	struct ec_params_console_read_v1 *read_params =
71 		(struct ec_params_console_read_v1 *)debug_info->read_msg->data;
72 	uint8_t *ec_buffer = (uint8_t *)debug_info->read_msg->data;
73 	int idx;
74 	int buf_space;
75 	int ret;
76 
77 	ret = cros_ec_cmd_xfer_status(ec->ec_dev, &snapshot_msg);
78 	if (ret < 0)
79 		goto resched;
80 
81 	/* Loop until we have read everything, or there's an error. */
82 	mutex_lock(&debug_info->log_mutex);
83 	buf_space = CIRC_SPACE(cb->head, cb->tail, LOG_SIZE);
84 
85 	while (1) {
86 		if (!buf_space) {
87 			dev_info_once(ec->dev,
88 				      "Some logs may have been dropped...\n");
89 			break;
90 		}
91 
92 		memset(read_params, '\0', sizeof(*read_params));
93 		read_params->subcmd = CONSOLE_READ_RECENT;
94 		ret = cros_ec_cmd_xfer_status(ec->ec_dev,
95 					      debug_info->read_msg);
96 		if (ret < 0)
97 			break;
98 
99 		/* If the buffer is empty, we're done here. */
100 		if (ret == 0 || ec_buffer[0] == '\0')
101 			break;
102 
103 		idx = 0;
104 		while (idx < ret && ec_buffer[idx] != '\0' && buf_space > 0) {
105 			cb->buf[cb->head] = ec_buffer[idx];
106 			cb->head = CIRC_ADD(cb->head, LOG_SIZE, 1);
107 			idx++;
108 			buf_space--;
109 		}
110 
111 		wake_up(&cros_ec_debugfs_log_wq);
112 	}
113 
114 	mutex_unlock(&debug_info->log_mutex);
115 
116 resched:
117 	schedule_delayed_work(&debug_info->log_poll_work,
118 			      msecs_to_jiffies(LOG_POLL_SEC * 1000));
119 }
120 
121 static int cros_ec_console_log_open(struct inode *inode, struct file *file)
122 {
123 	file->private_data = inode->i_private;
124 
125 	return stream_open(inode, file);
126 }
127 
128 static ssize_t cros_ec_console_log_read(struct file *file, char __user *buf,
129 					size_t count, loff_t *ppos)
130 {
131 	struct cros_ec_debugfs *debug_info = file->private_data;
132 	struct circ_buf *cb = &debug_info->log_buffer;
133 	ssize_t ret;
134 
135 	mutex_lock(&debug_info->log_mutex);
136 
137 	while (!CIRC_CNT(cb->head, cb->tail, LOG_SIZE)) {
138 		if (file->f_flags & O_NONBLOCK) {
139 			ret = -EAGAIN;
140 			goto error;
141 		}
142 
143 		mutex_unlock(&debug_info->log_mutex);
144 
145 		ret = wait_event_interruptible(cros_ec_debugfs_log_wq,
146 					CIRC_CNT(cb->head, cb->tail, LOG_SIZE));
147 		if (ret < 0)
148 			return ret;
149 
150 		mutex_lock(&debug_info->log_mutex);
151 	}
152 
153 	/* Only copy until the end of the circular buffer, and let userspace
154 	 * retry to get the rest of the data.
155 	 */
156 	ret = min_t(size_t, CIRC_CNT_TO_END(cb->head, cb->tail, LOG_SIZE),
157 		    count);
158 
159 	if (copy_to_user(buf, cb->buf + cb->tail, ret)) {
160 		ret = -EFAULT;
161 		goto error;
162 	}
163 
164 	cb->tail = CIRC_ADD(cb->tail, LOG_SIZE, ret);
165 
166 error:
167 	mutex_unlock(&debug_info->log_mutex);
168 	return ret;
169 }
170 
171 static __poll_t cros_ec_console_log_poll(struct file *file,
172 					     poll_table *wait)
173 {
174 	struct cros_ec_debugfs *debug_info = file->private_data;
175 	__poll_t mask = 0;
176 
177 	poll_wait(file, &cros_ec_debugfs_log_wq, wait);
178 
179 	mutex_lock(&debug_info->log_mutex);
180 	if (CIRC_CNT(debug_info->log_buffer.head,
181 		     debug_info->log_buffer.tail,
182 		     LOG_SIZE))
183 		mask |= EPOLLIN | EPOLLRDNORM;
184 	mutex_unlock(&debug_info->log_mutex);
185 
186 	return mask;
187 }
188 
189 static int cros_ec_console_log_release(struct inode *inode, struct file *file)
190 {
191 	return 0;
192 }
193 
194 static ssize_t cros_ec_pdinfo_read(struct file *file,
195 				   char __user *user_buf,
196 				   size_t count,
197 				   loff_t *ppos)
198 {
199 	char read_buf[EC_USB_PD_MAX_PORTS * 40], *p = read_buf;
200 	struct cros_ec_debugfs *debug_info = file->private_data;
201 	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
202 	struct {
203 		struct cros_ec_command msg;
204 		union {
205 			struct ec_response_usb_pd_control_v1 resp;
206 			struct ec_params_usb_pd_control params;
207 		};
208 	} __packed ec_buf;
209 	struct cros_ec_command *msg;
210 	struct ec_response_usb_pd_control_v1 *resp;
211 	struct ec_params_usb_pd_control *params;
212 	int i;
213 
214 	msg = &ec_buf.msg;
215 	params = (struct ec_params_usb_pd_control *)msg->data;
216 	resp = (struct ec_response_usb_pd_control_v1 *)msg->data;
217 
218 	msg->command = EC_CMD_USB_PD_CONTROL;
219 	msg->version = 1;
220 	msg->insize = sizeof(*resp);
221 	msg->outsize = sizeof(*params);
222 
223 	/*
224 	 * Read status from all PD ports until failure, typically caused
225 	 * by attempting to read status on a port that doesn't exist.
226 	 */
227 	for (i = 0; i < EC_USB_PD_MAX_PORTS; ++i) {
228 		params->port = i;
229 		params->role = 0;
230 		params->mux = 0;
231 		params->swap = 0;
232 
233 		if (cros_ec_cmd_xfer_status(ec_dev, msg) < 0)
234 			break;
235 
236 		p += scnprintf(p, sizeof(read_buf) + read_buf - p,
237 			       "p%d: %s en:%.2x role:%.2x pol:%.2x\n", i,
238 			       resp->state, resp->enabled, resp->role,
239 			       resp->polarity);
240 	}
241 
242 	return simple_read_from_buffer(user_buf, count, ppos,
243 				       read_buf, p - read_buf);
244 }
245 
246 static bool cros_ec_uptime_is_supported(struct cros_ec_device *ec_dev)
247 {
248 	struct {
249 		struct cros_ec_command cmd;
250 		struct ec_response_uptime_info resp;
251 	} __packed msg = {};
252 	int ret;
253 
254 	msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
255 	msg.cmd.insize = sizeof(msg.resp);
256 
257 	ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
258 	if (ret == -EPROTO && msg.cmd.result == EC_RES_INVALID_COMMAND)
259 		return false;
260 
261 	/* Other errors maybe a transient error, do not rule about support. */
262 	return true;
263 }
264 
265 static ssize_t cros_ec_uptime_read(struct file *file, char __user *user_buf,
266 				   size_t count, loff_t *ppos)
267 {
268 	struct cros_ec_debugfs *debug_info = file->private_data;
269 	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
270 	struct {
271 		struct cros_ec_command cmd;
272 		struct ec_response_uptime_info resp;
273 	} __packed msg = {};
274 	struct ec_response_uptime_info *resp;
275 	char read_buf[32];
276 	int ret;
277 
278 	resp = (struct ec_response_uptime_info *)&msg.resp;
279 
280 	msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
281 	msg.cmd.insize = sizeof(*resp);
282 
283 	ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
284 	if (ret < 0)
285 		return ret;
286 
287 	ret = scnprintf(read_buf, sizeof(read_buf), "%u\n",
288 			resp->time_since_ec_boot_ms);
289 
290 	return simple_read_from_buffer(user_buf, count, ppos, read_buf, ret);
291 }
292 
293 static const struct file_operations cros_ec_console_log_fops = {
294 	.owner = THIS_MODULE,
295 	.open = cros_ec_console_log_open,
296 	.read = cros_ec_console_log_read,
297 	.llseek = no_llseek,
298 	.poll = cros_ec_console_log_poll,
299 	.release = cros_ec_console_log_release,
300 };
301 
302 static const struct file_operations cros_ec_pdinfo_fops = {
303 	.owner = THIS_MODULE,
304 	.open = simple_open,
305 	.read = cros_ec_pdinfo_read,
306 	.llseek = default_llseek,
307 };
308 
309 static const struct file_operations cros_ec_uptime_fops = {
310 	.owner = THIS_MODULE,
311 	.open = simple_open,
312 	.read = cros_ec_uptime_read,
313 	.llseek = default_llseek,
314 };
315 
316 static int ec_read_version_supported(struct cros_ec_dev *ec)
317 {
318 	struct ec_params_get_cmd_versions_v1 *params;
319 	struct ec_response_get_cmd_versions *response;
320 	int ret;
321 
322 	struct cros_ec_command *msg;
323 
324 	msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
325 		GFP_KERNEL);
326 	if (!msg)
327 		return 0;
328 
329 	msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
330 	msg->outsize = sizeof(*params);
331 	msg->insize = sizeof(*response);
332 
333 	params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
334 	params->cmd = EC_CMD_CONSOLE_READ;
335 	response = (struct ec_response_get_cmd_versions *)msg->data;
336 
337 	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg) >= 0 &&
338 	      response->version_mask & EC_VER_MASK(1);
339 
340 	kfree(msg);
341 
342 	return ret;
343 }
344 
345 static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
346 {
347 	struct cros_ec_dev *ec = debug_info->ec;
348 	char *buf;
349 	int read_params_size;
350 	int read_response_size;
351 
352 	/*
353 	 * If the console log feature is not supported return silently and
354 	 * don't create the console_log entry.
355 	 */
356 	if (!ec_read_version_supported(ec))
357 		return 0;
358 
359 	buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
360 	if (!buf)
361 		return -ENOMEM;
362 
363 	read_params_size = sizeof(struct ec_params_console_read_v1);
364 	read_response_size = ec->ec_dev->max_response;
365 	debug_info->read_msg = devm_kzalloc(ec->dev,
366 		sizeof(*debug_info->read_msg) +
367 			max(read_params_size, read_response_size), GFP_KERNEL);
368 	if (!debug_info->read_msg)
369 		return -ENOMEM;
370 
371 	debug_info->read_msg->version = 1;
372 	debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
373 	debug_info->read_msg->outsize = read_params_size;
374 	debug_info->read_msg->insize = read_response_size;
375 
376 	debug_info->log_buffer.buf = buf;
377 	debug_info->log_buffer.head = 0;
378 	debug_info->log_buffer.tail = 0;
379 
380 	mutex_init(&debug_info->log_mutex);
381 
382 	debugfs_create_file("console_log", S_IFREG | 0444, debug_info->dir,
383 			    debug_info, &cros_ec_console_log_fops);
384 
385 	INIT_DELAYED_WORK(&debug_info->log_poll_work,
386 			  cros_ec_console_log_work);
387 	schedule_delayed_work(&debug_info->log_poll_work, 0);
388 
389 	return 0;
390 }
391 
392 static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
393 {
394 	if (debug_info->log_buffer.buf) {
395 		cancel_delayed_work_sync(&debug_info->log_poll_work);
396 		mutex_destroy(&debug_info->log_mutex);
397 	}
398 }
399 
400 static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
401 {
402 	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
403 	int ret;
404 	struct cros_ec_command *msg;
405 	int insize;
406 
407 	insize = ec_dev->max_response;
408 
409 	msg = devm_kzalloc(debug_info->ec->dev,
410 			sizeof(*msg) + insize, GFP_KERNEL);
411 	if (!msg)
412 		return -ENOMEM;
413 
414 	msg->command = EC_CMD_GET_PANIC_INFO;
415 	msg->insize = insize;
416 
417 	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
418 	if (ret < 0) {
419 		ret = 0;
420 		goto free;
421 	}
422 
423 	/* No panic data */
424 	if (ret == 0)
425 		goto free;
426 
427 	debug_info->panicinfo_blob.data = msg->data;
428 	debug_info->panicinfo_blob.size = ret;
429 
430 	debugfs_create_blob("panicinfo", S_IFREG | 0444, debug_info->dir,
431 			    &debug_info->panicinfo_blob);
432 
433 	return 0;
434 
435 free:
436 	devm_kfree(debug_info->ec->dev, msg);
437 	return ret;
438 }
439 
440 static int cros_ec_debugfs_probe(struct platform_device *pd)
441 {
442 	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
443 	struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
444 	const char *name = ec_platform->ec_name;
445 	struct cros_ec_debugfs *debug_info;
446 	int ret;
447 
448 	debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
449 	if (!debug_info)
450 		return -ENOMEM;
451 
452 	debug_info->ec = ec;
453 	debug_info->dir = debugfs_create_dir(name, NULL);
454 
455 	ret = cros_ec_create_panicinfo(debug_info);
456 	if (ret)
457 		goto remove_debugfs;
458 
459 	ret = cros_ec_create_console_log(debug_info);
460 	if (ret)
461 		goto remove_debugfs;
462 
463 	debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
464 			    &cros_ec_pdinfo_fops);
465 
466 	if (cros_ec_uptime_is_supported(ec->ec_dev))
467 		debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
468 				    &cros_ec_uptime_fops);
469 
470 	debugfs_create_x32("last_resume_result", 0444, debug_info->dir,
471 			   &ec->ec_dev->last_resume_result);
472 
473 	ec->debug_info = debug_info;
474 
475 	dev_set_drvdata(&pd->dev, ec);
476 
477 	return 0;
478 
479 remove_debugfs:
480 	debugfs_remove_recursive(debug_info->dir);
481 	return ret;
482 }
483 
484 static int cros_ec_debugfs_remove(struct platform_device *pd)
485 {
486 	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
487 
488 	debugfs_remove_recursive(ec->debug_info->dir);
489 	cros_ec_cleanup_console_log(ec->debug_info);
490 
491 	return 0;
492 }
493 
494 static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
495 {
496 	struct cros_ec_dev *ec = dev_get_drvdata(dev);
497 
498 	if (ec->debug_info->log_buffer.buf)
499 		cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
500 
501 	return 0;
502 }
503 
504 static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
505 {
506 	struct cros_ec_dev *ec = dev_get_drvdata(dev);
507 
508 	if (ec->debug_info->log_buffer.buf)
509 		schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
510 
511 	return 0;
512 }
513 
514 static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
515 			 cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
516 
517 static struct platform_driver cros_ec_debugfs_driver = {
518 	.driver = {
519 		.name = DRV_NAME,
520 		.pm = &cros_ec_debugfs_pm_ops,
521 	},
522 	.probe = cros_ec_debugfs_probe,
523 	.remove = cros_ec_debugfs_remove,
524 };
525 
526 module_platform_driver(cros_ec_debugfs_driver);
527 
528 MODULE_LICENSE("GPL");
529 MODULE_DESCRIPTION("Debug logs for ChromeOS EC");
530 MODULE_ALIAS("platform:" DRV_NAME);
531