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 */
 29static 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 */
 42struct 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 */
 58static 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
116resched:
117	schedule_delayed_work(&debug_info->log_poll_work,
118			      msecs_to_jiffies(LOG_POLL_SEC * 1000));
119}
120
121static 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
128static 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
166error:
167	mutex_unlock(&debug_info->log_mutex);
168	return ret;
169}
170
171static __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
189static int cros_ec_console_log_release(struct inode *inode, struct file *file)
190{
191	return 0;
192}
193
194static 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
246static 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
265static 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
293static 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
302static 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
309static 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
316static 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
345static 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
392static 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
400static 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
435free:
436	devm_kfree(debug_info->ec->dev, msg);
437	return ret;
438}
439
440static 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	debugfs_create_u16("suspend_timeout_ms", 0664, debug_info->dir,
474			   &ec->ec_dev->suspend_timeout_ms);
475
476	ec->debug_info = debug_info;
477
478	dev_set_drvdata(&pd->dev, ec);
479
480	return 0;
481
482remove_debugfs:
483	debugfs_remove_recursive(debug_info->dir);
484	return ret;
485}
486
487static int cros_ec_debugfs_remove(struct platform_device *pd)
488{
489	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
490
491	debugfs_remove_recursive(ec->debug_info->dir);
492	cros_ec_cleanup_console_log(ec->debug_info);
493
494	return 0;
495}
496
497static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
498{
499	struct cros_ec_dev *ec = dev_get_drvdata(dev);
500
501	if (ec->debug_info->log_buffer.buf)
502		cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
503
504	return 0;
505}
506
507static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
508{
509	struct cros_ec_dev *ec = dev_get_drvdata(dev);
510
511	if (ec->debug_info->log_buffer.buf)
512		schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
513
514	return 0;
515}
516
517static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
518			 cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
519
520static struct platform_driver cros_ec_debugfs_driver = {
521	.driver = {
522		.name = DRV_NAME,
523		.pm = &cros_ec_debugfs_pm_ops,
524		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
525	},
526	.probe = cros_ec_debugfs_probe,
527	.remove = cros_ec_debugfs_remove,
528};
529
530module_platform_driver(cros_ec_debugfs_driver);
531
532MODULE_LICENSE("GPL");
533MODULE_DESCRIPTION("Debug logs for ChromeOS EC");
534MODULE_ALIAS("platform:" DRV_NAME);