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	struct {
211		struct cros_ec_command msg;
212		union {
213			struct ec_response_usb_pd_control_v1 resp;
214			struct ec_params_usb_pd_control params;
215		};
216	} __packed ec_buf;
217	struct cros_ec_command *msg;
218	struct ec_response_usb_pd_control_v1 *resp;
219	struct ec_params_usb_pd_control *params;
220	int i;
221
222	msg = &ec_buf.msg;
223	params = (struct ec_params_usb_pd_control *)msg->data;
224	resp = (struct ec_response_usb_pd_control_v1 *)msg->data;
225
226	msg->command = EC_CMD_USB_PD_CONTROL;
227	msg->version = 1;
228	msg->insize = sizeof(*resp);
229	msg->outsize = sizeof(*params);
230
231	/*
232	 * Read status from all PD ports until failure, typically caused
233	 * by attempting to read status on a port that doesn't exist.
234	 */
235	for (i = 0; i < EC_USB_PD_MAX_PORTS; ++i) {
236		params->port = i;
237		params->role = 0;
238		params->mux = 0;
239		params->swap = 0;
240
241		if (cros_ec_cmd_xfer_status(ec_dev, msg) < 0)
242			break;
243
244		p += scnprintf(p, sizeof(read_buf) + read_buf - p,
245			       "p%d: %s en:%.2x role:%.2x pol:%.2x\n", i,
246			       resp->state, resp->enabled, resp->role,
247			       resp->polarity);
248	}
249
250	return simple_read_from_buffer(user_buf, count, ppos,
251				       read_buf, p - read_buf);
252}
253
254static bool cros_ec_uptime_is_supported(struct cros_ec_device *ec_dev)
255{
256	struct {
257		struct cros_ec_command cmd;
258		struct ec_response_uptime_info resp;
259	} __packed msg = {};
260	int ret;
261
262	msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
263	msg.cmd.insize = sizeof(msg.resp);
264
265	ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
266	if (ret == -EPROTO && msg.cmd.result == EC_RES_INVALID_COMMAND)
267		return false;
268
269	/* Other errors maybe a transient error, do not rule about support. */
270	return true;
271}
272
273static ssize_t cros_ec_uptime_read(struct file *file, char __user *user_buf,
274				   size_t count, loff_t *ppos)
275{
276	struct cros_ec_debugfs *debug_info = file->private_data;
277	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
278	struct {
279		struct cros_ec_command cmd;
280		struct ec_response_uptime_info resp;
281	} __packed msg = {};
282	struct ec_response_uptime_info *resp;
283	char read_buf[32];
284	int ret;
285
286	resp = (struct ec_response_uptime_info *)&msg.resp;
287
288	msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
289	msg.cmd.insize = sizeof(*resp);
290
291	ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
292	if (ret < 0)
293		return ret;
294
295	ret = scnprintf(read_buf, sizeof(read_buf), "%u\n",
296			resp->time_since_ec_boot_ms);
297
298	return simple_read_from_buffer(user_buf, count, ppos, read_buf, ret);
299}
300
301static const struct file_operations cros_ec_console_log_fops = {
302	.owner = THIS_MODULE,
303	.open = cros_ec_console_log_open,
304	.read = cros_ec_console_log_read,
305	.poll = cros_ec_console_log_poll,
306	.release = cros_ec_console_log_release,
307};
308
309static const struct file_operations cros_ec_pdinfo_fops = {
310	.owner = THIS_MODULE,
311	.open = simple_open,
312	.read = cros_ec_pdinfo_read,
313	.llseek = default_llseek,
314};
315
316static const struct file_operations cros_ec_uptime_fops = {
317	.owner = THIS_MODULE,
318	.open = simple_open,
319	.read = cros_ec_uptime_read,
320	.llseek = default_llseek,
321};
322
323static int ec_read_version_supported(struct cros_ec_dev *ec)
324{
325	struct ec_params_get_cmd_versions_v1 *params;
326	struct ec_response_get_cmd_versions *response;
327	int ret;
328
329	struct cros_ec_command *msg;
330
331	msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
332		GFP_KERNEL);
333	if (!msg)
334		return 0;
335
336	msg->version = 1;
337	msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
338	msg->outsize = sizeof(*params);
339	msg->insize = sizeof(*response);
340
341	params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
342	params->cmd = EC_CMD_CONSOLE_READ;
343	response = (struct ec_response_get_cmd_versions *)msg->data;
344
345	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg) >= 0 &&
346	      response->version_mask & EC_VER_MASK(1);
347
348	kfree(msg);
349
350	return ret;
351}
352
353static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
354{
355	struct cros_ec_dev *ec = debug_info->ec;
356	char *buf;
357	int read_params_size;
358	int read_response_size;
359
360	/*
361	 * If the console log feature is not supported return silently and
362	 * don't create the console_log entry.
363	 */
364	if (!ec_read_version_supported(ec))
365		return 0;
366
367	buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
368	if (!buf)
369		return -ENOMEM;
370
371	read_params_size = sizeof(struct ec_params_console_read_v1);
372	read_response_size = ec->ec_dev->max_response;
373	debug_info->read_msg = devm_kzalloc(ec->dev,
374		sizeof(*debug_info->read_msg) +
375			max(read_params_size, read_response_size), GFP_KERNEL);
376	if (!debug_info->read_msg)
377		return -ENOMEM;
378
379	debug_info->read_msg->version = 1;
380	debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
381	debug_info->read_msg->outsize = read_params_size;
382	debug_info->read_msg->insize = read_response_size;
383
384	debug_info->log_buffer.buf = buf;
385	debug_info->log_buffer.head = 0;
386	debug_info->log_buffer.tail = 0;
387
388	mutex_init(&debug_info->log_mutex);
389
390	debugfs_create_file("console_log", S_IFREG | 0444, debug_info->dir,
391			    debug_info, &cros_ec_console_log_fops);
392
393	INIT_DELAYED_WORK(&debug_info->log_poll_work,
394			  cros_ec_console_log_work);
395	schedule_delayed_work(&debug_info->log_poll_work, 0);
396
397	return 0;
398}
399
400static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
401{
402	if (debug_info->log_buffer.buf) {
403		cancel_delayed_work_sync(&debug_info->log_poll_work);
404		mutex_destroy(&debug_info->log_mutex);
405	}
406}
407
408/*
409 * Returns the size of the panicinfo data fetched from the EC
410 */
411static int cros_ec_get_panicinfo(struct cros_ec_device *ec_dev, uint8_t *data,
412				 int data_size)
413{
414	int ret;
415	struct cros_ec_command *msg;
416
417	if (!data || data_size <= 0 || data_size > ec_dev->max_response)
418		return -EINVAL;
419
420	msg = kzalloc(sizeof(*msg) + data_size, GFP_KERNEL);
421	if (!msg)
422		return -ENOMEM;
423
424	msg->command = EC_CMD_GET_PANIC_INFO;
425	msg->insize = data_size;
426
427	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
428	if (ret < 0)
429		goto free;
430
431	memcpy(data, msg->data, data_size);
432
433free:
434	kfree(msg);
435	return ret;
436}
437
438static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
439{
440	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
441	int ret;
442	void *data;
443
444	data = devm_kzalloc(debug_info->ec->dev, ec_dev->max_response,
445			    GFP_KERNEL);
446	if (!data)
447		return -ENOMEM;
448
449	ret = cros_ec_get_panicinfo(ec_dev, data, ec_dev->max_response);
450	if (ret < 0) {
451		ret = 0;
452		goto free;
453	}
454
455	/* No panic data */
456	if (ret == 0)
457		goto free;
458
459	debug_info->panicinfo_blob.data = data;
460	debug_info->panicinfo_blob.size = ret;
461
462	debugfs_create_blob("panicinfo", 0444, debug_info->dir,
463			    &debug_info->panicinfo_blob);
464
465	return 0;
466
467free:
468	devm_kfree(debug_info->ec->dev, data);
469	return ret;
470}
471
472static int cros_ec_debugfs_panic_event(struct notifier_block *nb,
473				       unsigned long queued_during_suspend, void *_notify)
474{
475	struct cros_ec_debugfs *debug_info =
476		container_of(nb, struct cros_ec_debugfs, notifier_panic);
477
478	if (debug_info->log_buffer.buf) {
479		/* Force log poll work to run immediately */
480		mod_delayed_work(debug_info->log_poll_work.wq, &debug_info->log_poll_work, 0);
481		/* Block until log poll work finishes */
482		flush_delayed_work(&debug_info->log_poll_work);
483	}
484
485	return NOTIFY_DONE;
486}
487
488static int cros_ec_debugfs_probe(struct platform_device *pd)
489{
490	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
491	struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
492	const char *name = ec_platform->ec_name;
493	struct cros_ec_debugfs *debug_info;
494	int ret;
495
496	debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
497	if (!debug_info)
498		return -ENOMEM;
499
500	debug_info->ec = ec;
501	debug_info->dir = debugfs_create_dir(name, NULL);
502
503	ret = cros_ec_create_panicinfo(debug_info);
504	if (ret)
505		goto remove_debugfs;
506
507	ret = cros_ec_create_console_log(debug_info);
508	if (ret)
509		goto remove_debugfs;
510
511	debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
512			    &cros_ec_pdinfo_fops);
513
514	if (cros_ec_uptime_is_supported(ec->ec_dev))
515		debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
516				    &cros_ec_uptime_fops);
517
518	debugfs_create_x32("last_resume_result", 0444, debug_info->dir,
519			   &ec->ec_dev->last_resume_result);
520
521	debugfs_create_u16("suspend_timeout_ms", 0664, debug_info->dir,
522			   &ec->ec_dev->suspend_timeout_ms);
523
524	debug_info->notifier_panic.notifier_call = cros_ec_debugfs_panic_event;
525	ret = blocking_notifier_chain_register(&ec->ec_dev->panic_notifier,
526					       &debug_info->notifier_panic);
527	if (ret)
528		goto remove_debugfs;
529
530	ec->debug_info = debug_info;
531
532	dev_set_drvdata(&pd->dev, ec);
533
534	return 0;
535
536remove_debugfs:
537	debugfs_remove_recursive(debug_info->dir);
538	return ret;
539}
540
541static void cros_ec_debugfs_remove(struct platform_device *pd)
542{
543	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
544
545	debugfs_remove_recursive(ec->debug_info->dir);
546	cros_ec_cleanup_console_log(ec->debug_info);
547}
548
549static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
550{
551	struct cros_ec_dev *ec = dev_get_drvdata(dev);
552
553	if (ec->debug_info->log_buffer.buf)
554		cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
555
556	return 0;
557}
558
559static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
560{
561	struct cros_ec_dev *ec = dev_get_drvdata(dev);
562
563	if (ec->debug_info->log_buffer.buf)
564		schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
565
566	return 0;
567}
568
569static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
570			 cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
571
572static const struct platform_device_id cros_ec_debugfs_id[] = {
573	{ DRV_NAME, 0 },
574	{}
575};
576MODULE_DEVICE_TABLE(platform, cros_ec_debugfs_id);
577
578static struct platform_driver cros_ec_debugfs_driver = {
579	.driver = {
580		.name = DRV_NAME,
581		.pm = &cros_ec_debugfs_pm_ops,
582		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
583	},
584	.probe = cros_ec_debugfs_probe,
585	.remove = cros_ec_debugfs_remove,
586	.id_table = cros_ec_debugfs_id,
587};
588
589module_platform_driver(cros_ec_debugfs_driver);
590
591MODULE_LICENSE("GPL");
592MODULE_DESCRIPTION("Debug logs for ChromeOS EC");