cros_ec_debugfs.c

  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/mod_devicetable.h>
 11#include <linux/module.h>
 12#include <linux/mutex.h>
 13#include <linux/platform_data/cros_ec_commands.h>
 14#include <linux/platform_data/cros_ec_proto.h>
 15#include <linux/platform_device.h>
 16#include <linux/poll.h>
 17#include <linux/sched.h>
 18#include <linux/slab.h>
 19#include <linux/wait.h>
 20
 21#define DRV_NAME "cros-ec-debugfs"
 22
 23#define LOG_SHIFT		14
 24#define LOG_SIZE		(1 << LOG_SHIFT)
 25#define LOG_POLL_SEC		10
 26
 27#define CIRC_ADD(idx, size, value)	(((idx) + (value)) & ((size) - 1))
 28
 29static unsigned int log_poll_period_ms = LOG_POLL_SEC * MSEC_PER_SEC;
 30module_param(log_poll_period_ms, uint, 0644);
 31MODULE_PARM_DESC(log_poll_period_ms, "EC log polling period(ms)");
 32
 33/* waitqueue for log readers */
 34static DECLARE_WAIT_QUEUE_HEAD(cros_ec_debugfs_log_wq);
 35
 36/**
 37 * struct cros_ec_debugfs - EC debugging information.
 38 *
 39 * @ec: EC device this debugfs information belongs to
 40 * @dir: dentry for debugfs files
 41 * @log_buffer: circular buffer for console log information
 42 * @read_msg: preallocated EC command and buffer to read console log
 43 * @log_mutex: mutex to protect circular buffer
 44 * @log_poll_work: recurring task to poll EC for new console log data
 45 * @panicinfo_blob: panicinfo debugfs blob
 46 * @notifier_panic: notifier_block to let kernel to flush buffered log
 47 *                  when EC panic
 48 */
 49struct 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	struct delayed_work log_poll_work;
 57	/* EC panicinfo */
 58	struct debugfs_blob_wrapper panicinfo_blob;
 59	struct notifier_block notifier_panic;
 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_period_ms.
 65 */
 66static 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_status(ec->ec_dev, &snapshot_msg);
 86	if (ret < 0)
 87		goto resched;
 88
 89	/* Loop until we have read everything, or there's an error. */
 90	mutex_lock(&debug_info->log_mutex);
 91	buf_space = CIRC_SPACE(cb->head, cb->tail, LOG_SIZE);
 92
 93	while (1) {
 94		if (!buf_space) {
 95			dev_info_once(ec->dev,
 96				      "Some logs may have been dropped...\n");
 97			break;
 98		}
 99
100		memset(read_params, '\0', sizeof(*read_params));
101		read_params->subcmd = CONSOLE_READ_RECENT;
102		ret = cros_ec_cmd_xfer_status(ec->ec_dev,
103					      debug_info->read_msg);
104		if (ret < 0)
105			break;
106
107		/* If the buffer is empty, we're done here. */
108		if (ret == 0 || ec_buffer[0] == '\0')
109			break;
110
111		idx = 0;
112		while (idx < ret && ec_buffer[idx] != '\0' && buf_space > 0) {
113			cb->buf[cb->head] = ec_buffer[idx];
114			cb->head = CIRC_ADD(cb->head, LOG_SIZE, 1);
115			idx++;
116			buf_space--;
117		}
118
119		wake_up(&cros_ec_debugfs_log_wq);
120	}
121
122	mutex_unlock(&debug_info->log_mutex);
123
124resched:
125	schedule_delayed_work(&debug_info->log_poll_work,
126			      msecs_to_jiffies(log_poll_period_ms));
127}
128
129static int cros_ec_console_log_open(struct inode *inode, struct file *file)
130{
131	file->private_data = inode->i_private;
132
133	return stream_open(inode, file);
134}
135
136static ssize_t cros_ec_console_log_read(struct file *file, char __user *buf,
137					size_t count, loff_t *ppos)
138{
139	struct cros_ec_debugfs *debug_info = file->private_data;
140	struct circ_buf *cb = &debug_info->log_buffer;
141	ssize_t ret;
142
143	mutex_lock(&debug_info->log_mutex);
144
145	while (!CIRC_CNT(cb->head, cb->tail, LOG_SIZE)) {
146		if (file->f_flags & O_NONBLOCK) {
147			ret = -EAGAIN;
148			goto error;
149		}
150
151		mutex_unlock(&debug_info->log_mutex);
152
153		ret = wait_event_interruptible(cros_ec_debugfs_log_wq,
154					CIRC_CNT(cb->head, cb->tail, LOG_SIZE));
155		if (ret < 0)
156			return ret;
157
158		mutex_lock(&debug_info->log_mutex);
159	}
160
161	/* Only copy until the end of the circular buffer, and let userspace
162	 * retry to get the rest of the data.
163	 */
164	ret = min_t(size_t, CIRC_CNT_TO_END(cb->head, cb->tail, LOG_SIZE),
165		    count);
166
167	if (copy_to_user(buf, cb->buf + cb->tail, ret)) {
168		ret = -EFAULT;
169		goto error;
170	}
171
172	cb->tail = CIRC_ADD(cb->tail, LOG_SIZE, ret);
173
174error:
175	mutex_unlock(&debug_info->log_mutex);
176	return ret;
177}
178
179static __poll_t cros_ec_console_log_poll(struct file *file,
180					     poll_table *wait)
181{
182	struct cros_ec_debugfs *debug_info = file->private_data;
183	__poll_t mask = 0;
184
185	poll_wait(file, &cros_ec_debugfs_log_wq, wait);
186
187	mutex_lock(&debug_info->log_mutex);
188	if (CIRC_CNT(debug_info->log_buffer.head,
189		     debug_info->log_buffer.tail,
190		     LOG_SIZE))
191		mask |= EPOLLIN | EPOLLRDNORM;
192	mutex_unlock(&debug_info->log_mutex);
193
194	return mask;
195}
196
197static int cros_ec_console_log_release(struct inode *inode, struct file *file)
198{
199	return 0;
200}
201
202static ssize_t cros_ec_pdinfo_read(struct file *file,
203				   char __user *user_buf,
204				   size_t count,
205				   loff_t *ppos)
206{
207	char read_buf[EC_USB_PD_MAX_PORTS * 40], *p = read_buf;
208	struct cros_ec_debugfs *debug_info = file->private_data;
209	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
210	DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
211			MAX(sizeof(struct ec_response_usb_pd_control_v1),
212			    sizeof(struct ec_params_usb_pd_control)));
213	struct ec_response_usb_pd_control_v1 *resp =
214			(struct ec_response_usb_pd_control_v1 *)msg->data;
215	struct ec_params_usb_pd_control *params =
216			(struct ec_params_usb_pd_control *)msg->data;
217	int i;
218
219	msg->command = EC_CMD_USB_PD_CONTROL;
220	msg->version = 1;
221	msg->insize = sizeof(*resp);
222	msg->outsize = sizeof(*params);
223
224	/*
225	 * Read status from all PD ports until failure, typically caused
226	 * by attempting to read status on a port that doesn't exist.
227	 */
228	for (i = 0; i < EC_USB_PD_MAX_PORTS; ++i) {
229		params->port = i;
230		params->role = 0;
231		params->mux = 0;
232		params->swap = 0;
233
234		if (cros_ec_cmd_xfer_status(ec_dev, msg) < 0)
235			break;
236
237		p += scnprintf(p, sizeof(read_buf) + read_buf - p,
238			       "p%d: %s en:%.2x role:%.2x pol:%.2x\n", i,
239			       resp->state, resp->enabled, resp->role,
240			       resp->polarity);
241	}
242
243	return simple_read_from_buffer(user_buf, count, ppos,
244				       read_buf, p - read_buf);
245}
246
247static bool cros_ec_uptime_is_supported(struct cros_ec_device *ec_dev)
248{
249	DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
250			sizeof(struct ec_response_uptime_info));
251	int ret;
252
253	msg->command = EC_CMD_GET_UPTIME_INFO;
254	msg->insize = sizeof(struct ec_response_uptime_info);
255
256	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
257	if (ret == -EPROTO && msg->result == EC_RES_INVALID_COMMAND)
258		return false;
259
260	/* Other errors maybe a transient error, do not rule about support. */
261	return true;
262}
263
264static ssize_t cros_ec_uptime_read(struct file *file, char __user *user_buf,
265				   size_t count, loff_t *ppos)
266{
267	struct cros_ec_debugfs *debug_info = file->private_data;
268	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
269	DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
270			sizeof(struct ec_response_uptime_info));
271	struct ec_response_uptime_info *resp =
272				(struct ec_response_uptime_info *)msg->data;
273	char read_buf[32];
274	int ret;
275
276	msg->command = EC_CMD_GET_UPTIME_INFO;
277	msg->insize = sizeof(*resp);
278
279	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
280	if (ret < 0)
281		return ret;
282
283	ret = scnprintf(read_buf, sizeof(read_buf), "%u\n",
284			resp->time_since_ec_boot_ms);
285
286	return simple_read_from_buffer(user_buf, count, ppos, read_buf, ret);
287}
288
289static const struct file_operations cros_ec_console_log_fops = {
290	.owner = THIS_MODULE,
291	.open = cros_ec_console_log_open,
292	.read = cros_ec_console_log_read,
293	.poll = cros_ec_console_log_poll,
294	.release = cros_ec_console_log_release,
295};
296
297static const struct file_operations cros_ec_pdinfo_fops = {
298	.owner = THIS_MODULE,
299	.open = simple_open,
300	.read = cros_ec_pdinfo_read,
301	.llseek = default_llseek,
302};
303
304static const struct file_operations cros_ec_uptime_fops = {
305	.owner = THIS_MODULE,
306	.open = simple_open,
307	.read = cros_ec_uptime_read,
308	.llseek = default_llseek,
309};
310
311static int ec_read_version_supported(struct cros_ec_dev *ec)
312{
313	struct ec_params_get_cmd_versions_v1 *params;
314	struct ec_response_get_cmd_versions *response;
315	int ret;
316
317	struct cros_ec_command *msg;
318
319	msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
320		GFP_KERNEL);
321	if (!msg)
322		return 0;
323
324	msg->version = 1;
325	msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
326	msg->outsize = sizeof(*params);
327	msg->insize = sizeof(*response);
328
329	params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
330	params->cmd = EC_CMD_CONSOLE_READ;
331	response = (struct ec_response_get_cmd_versions *)msg->data;
332
333	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg) >= 0 &&
334	      response->version_mask & EC_VER_MASK(1);
335
336	kfree(msg);
337
338	return ret;
339}
340
341static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
342{
343	struct cros_ec_dev *ec = debug_info->ec;
344	char *buf;
345	int read_params_size;
346	int read_response_size;
347
348	/*
349	 * If the console log feature is not supported return silently and
350	 * don't create the console_log entry.
351	 */
352	if (!ec_read_version_supported(ec))
353		return 0;
354
355	buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
356	if (!buf)
357		return -ENOMEM;
358
359	read_params_size = sizeof(struct ec_params_console_read_v1);
360	read_response_size = ec->ec_dev->max_response;
361	debug_info->read_msg = devm_kzalloc(ec->dev,
362		sizeof(*debug_info->read_msg) +
363			max(read_params_size, read_response_size), GFP_KERNEL);
364	if (!debug_info->read_msg)
365		return -ENOMEM;
366
367	debug_info->read_msg->version = 1;
368	debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
369	debug_info->read_msg->outsize = read_params_size;
370	debug_info->read_msg->insize = read_response_size;
371
372	debug_info->log_buffer.buf = buf;
373	debug_info->log_buffer.head = 0;
374	debug_info->log_buffer.tail = 0;
375
376	mutex_init(&debug_info->log_mutex);
377
378	debugfs_create_file("console_log", S_IFREG | 0444, debug_info->dir,
379			    debug_info, &cros_ec_console_log_fops);
380
381	INIT_DELAYED_WORK(&debug_info->log_poll_work,
382			  cros_ec_console_log_work);
383	schedule_delayed_work(&debug_info->log_poll_work, 0);
384
385	return 0;
386}
387
388static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
389{
390	if (debug_info->log_buffer.buf) {
391		cancel_delayed_work_sync(&debug_info->log_poll_work);
392		mutex_destroy(&debug_info->log_mutex);
393	}
394}
395
396/*
397 * Returns the size of the panicinfo data fetched from the EC
398 */
399static int cros_ec_get_panicinfo(struct cros_ec_device *ec_dev, uint8_t *data,
400				 int data_size)
401{
402	int ret;
403	struct cros_ec_command *msg;
404
405	if (!data || data_size <= 0 || data_size > ec_dev->max_response)
406		return -EINVAL;
407
408	msg = kzalloc(sizeof(*msg) + data_size, GFP_KERNEL);
409	if (!msg)
410		return -ENOMEM;
411
412	msg->command = EC_CMD_GET_PANIC_INFO;
413	msg->insize = data_size;
414
415	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
416	if (ret < 0)
417		goto free;
418
419	memcpy(data, msg->data, data_size);
420
421free:
422	kfree(msg);
423	return ret;
424}
425
426static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
427{
428	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
429	int ret;
430	void *data;
431
432	data = devm_kzalloc(debug_info->ec->dev, ec_dev->max_response,
433			    GFP_KERNEL);
434	if (!data)
435		return -ENOMEM;
436
437	ret = cros_ec_get_panicinfo(ec_dev, data, ec_dev->max_response);
438	if (ret < 0) {
439		ret = 0;
440		goto free;
441	}
442
443	/* No panic data */
444	if (ret == 0)
445		goto free;
446
447	debug_info->panicinfo_blob.data = data;
448	debug_info->panicinfo_blob.size = ret;
449
450	debugfs_create_blob("panicinfo", 0444, debug_info->dir,
451			    &debug_info->panicinfo_blob);
452
453	return 0;
454
455free:
456	devm_kfree(debug_info->ec->dev, data);
457	return ret;
458}
459
460static int cros_ec_debugfs_panic_event(struct notifier_block *nb,
461				       unsigned long queued_during_suspend, void *_notify)
462{
463	struct cros_ec_debugfs *debug_info =
464		container_of(nb, struct cros_ec_debugfs, notifier_panic);
465
466	if (debug_info->log_buffer.buf) {
467		/* Force log poll work to run immediately */
468		mod_delayed_work(debug_info->log_poll_work.wq, &debug_info->log_poll_work, 0);
469		/* Block until log poll work finishes */
470		flush_delayed_work(&debug_info->log_poll_work);
471	}
472
473	return NOTIFY_DONE;
474}
475
476static int cros_ec_debugfs_probe(struct platform_device *pd)
477{
478	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
479	struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
480	const char *name = ec_platform->ec_name;
481	struct cros_ec_debugfs *debug_info;
482	int ret;
483
484	debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
485	if (!debug_info)
486		return -ENOMEM;
487
488	debug_info->ec = ec;
489	debug_info->dir = debugfs_create_dir(name, NULL);
490
491	ret = cros_ec_create_panicinfo(debug_info);
492	if (ret)
493		goto remove_debugfs;
494
495	ret = cros_ec_create_console_log(debug_info);
496	if (ret)
497		goto remove_debugfs;
498
499	debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
500			    &cros_ec_pdinfo_fops);
501
502	if (cros_ec_uptime_is_supported(ec->ec_dev))
503		debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
504				    &cros_ec_uptime_fops);
505
506	debugfs_create_x32("last_resume_result", 0444, debug_info->dir,
507			   &ec->ec_dev->last_resume_result);
508
509	debugfs_create_u16("suspend_timeout_ms", 0664, debug_info->dir,
510			   &ec->ec_dev->suspend_timeout_ms);
511
512	debug_info->notifier_panic.notifier_call = cros_ec_debugfs_panic_event;
513	ret = blocking_notifier_chain_register(&ec->ec_dev->panic_notifier,
514					       &debug_info->notifier_panic);
515	if (ret)
516		goto remove_debugfs;
517
518	ec->debug_info = debug_info;
519
520	dev_set_drvdata(&pd->dev, ec);
521
522	return 0;
523
524remove_debugfs:
525	debugfs_remove_recursive(debug_info->dir);
526	return ret;
527}
528
529static void cros_ec_debugfs_remove(struct platform_device *pd)
530{
531	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
532
533	debugfs_remove_recursive(ec->debug_info->dir);
534	cros_ec_cleanup_console_log(ec->debug_info);
535}
536
537static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
538{
539	struct cros_ec_dev *ec = dev_get_drvdata(dev);
540
541	if (ec->debug_info->log_buffer.buf)
542		cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
543
544	return 0;
545}
546
547static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
548{
549	struct cros_ec_dev *ec = dev_get_drvdata(dev);
550
551	if (ec->debug_info->log_buffer.buf)
552		schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
553
554	return 0;
555}
556
557static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
558			 cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
559
560static const struct platform_device_id cros_ec_debugfs_id[] = {
561	{ DRV_NAME, 0 },
562	{}
563};
564MODULE_DEVICE_TABLE(platform, cros_ec_debugfs_id);
565
566static struct platform_driver cros_ec_debugfs_driver = {
567	.driver = {
568		.name = DRV_NAME,
569		.pm = &cros_ec_debugfs_pm_ops,
570		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
571	},
572	.probe = cros_ec_debugfs_probe,
573	.remove = cros_ec_debugfs_remove,
574	.id_table = cros_ec_debugfs_id,
575};
576
577module_platform_driver(cros_ec_debugfs_driver);
578
579MODULE_LICENSE("GPL");
580MODULE_DESCRIPTION("Debug logs for ChromeOS EC");