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 * @notifier_panic: notifier_block to let kernel to flush buffered log
 42 *                  when EC panic
 43 */
 44struct cros_ec_debugfs {
 45	struct cros_ec_dev *ec;
 46	struct dentry *dir;
 47	/* EC log */
 48	struct circ_buf log_buffer;
 49	struct cros_ec_command *read_msg;
 50	struct mutex log_mutex;
 51	struct delayed_work log_poll_work;
 52	/* EC panicinfo */
 53	struct debugfs_blob_wrapper panicinfo_blob;
 54	struct notifier_block notifier_panic;
 55};
 56
 57/*
 58 * We need to make sure that the EC log buffer on the UART is large enough,
 59 * so that it is unlikely enough to overlow within LOG_POLL_SEC.
 60 */
 61static void cros_ec_console_log_work(struct work_struct *__work)
 62{
 63	struct cros_ec_debugfs *debug_info =
 64		container_of(to_delayed_work(__work),
 65			     struct cros_ec_debugfs,
 66			     log_poll_work);
 67	struct cros_ec_dev *ec = debug_info->ec;
 68	struct circ_buf *cb = &debug_info->log_buffer;
 69	struct cros_ec_command snapshot_msg = {
 70		.command = EC_CMD_CONSOLE_SNAPSHOT + ec->cmd_offset,
 71	};
 72
 73	struct ec_params_console_read_v1 *read_params =
 74		(struct ec_params_console_read_v1 *)debug_info->read_msg->data;
 75	uint8_t *ec_buffer = (uint8_t *)debug_info->read_msg->data;
 76	int idx;
 77	int buf_space;
 78	int ret;
 79
 80	ret = cros_ec_cmd_xfer_status(ec->ec_dev, &snapshot_msg);
 81	if (ret < 0)
 82		goto resched;
 83
 84	/* Loop until we have read everything, or there's an error. */
 85	mutex_lock(&debug_info->log_mutex);
 86	buf_space = CIRC_SPACE(cb->head, cb->tail, LOG_SIZE);
 87
 88	while (1) {
 89		if (!buf_space) {
 90			dev_info_once(ec->dev,
 91				      "Some logs may have been dropped...\n");
 92			break;
 93		}
 94
 95		memset(read_params, '\0', sizeof(*read_params));
 96		read_params->subcmd = CONSOLE_READ_RECENT;
 97		ret = cros_ec_cmd_xfer_status(ec->ec_dev,
 98					      debug_info->read_msg);
 99		if (ret < 0)
100			break;
101
102		/* If the buffer is empty, we're done here. */
103		if (ret == 0 || ec_buffer[0] == '\0')
104			break;
105
106		idx = 0;
107		while (idx < ret && ec_buffer[idx] != '\0' && buf_space > 0) {
108			cb->buf[cb->head] = ec_buffer[idx];
109			cb->head = CIRC_ADD(cb->head, LOG_SIZE, 1);
110			idx++;
111			buf_space--;
112		}
113
114		wake_up(&cros_ec_debugfs_log_wq);
115	}
116
117	mutex_unlock(&debug_info->log_mutex);
118
119resched:
120	schedule_delayed_work(&debug_info->log_poll_work,
121			      msecs_to_jiffies(LOG_POLL_SEC * 1000));
122}
123
124static int cros_ec_console_log_open(struct inode *inode, struct file *file)
125{
126	file->private_data = inode->i_private;
127
128	return stream_open(inode, file);
129}
130
131static ssize_t cros_ec_console_log_read(struct file *file, char __user *buf,
132					size_t count, loff_t *ppos)
133{
134	struct cros_ec_debugfs *debug_info = file->private_data;
135	struct circ_buf *cb = &debug_info->log_buffer;
136	ssize_t ret;
137
138	mutex_lock(&debug_info->log_mutex);
139
140	while (!CIRC_CNT(cb->head, cb->tail, LOG_SIZE)) {
141		if (file->f_flags & O_NONBLOCK) {
142			ret = -EAGAIN;
143			goto error;
144		}
145
146		mutex_unlock(&debug_info->log_mutex);
147
148		ret = wait_event_interruptible(cros_ec_debugfs_log_wq,
149					CIRC_CNT(cb->head, cb->tail, LOG_SIZE));
150		if (ret < 0)
151			return ret;
152
153		mutex_lock(&debug_info->log_mutex);
154	}
155
156	/* Only copy until the end of the circular buffer, and let userspace
157	 * retry to get the rest of the data.
158	 */
159	ret = min_t(size_t, CIRC_CNT_TO_END(cb->head, cb->tail, LOG_SIZE),
160		    count);
161
162	if (copy_to_user(buf, cb->buf + cb->tail, ret)) {
163		ret = -EFAULT;
164		goto error;
165	}
166
167	cb->tail = CIRC_ADD(cb->tail, LOG_SIZE, ret);
168
169error:
170	mutex_unlock(&debug_info->log_mutex);
171	return ret;
172}
173
174static __poll_t cros_ec_console_log_poll(struct file *file,
175					     poll_table *wait)
176{
177	struct cros_ec_debugfs *debug_info = file->private_data;
178	__poll_t mask = 0;
179
180	poll_wait(file, &cros_ec_debugfs_log_wq, wait);
181
182	mutex_lock(&debug_info->log_mutex);
183	if (CIRC_CNT(debug_info->log_buffer.head,
184		     debug_info->log_buffer.tail,
185		     LOG_SIZE))
186		mask |= EPOLLIN | EPOLLRDNORM;
187	mutex_unlock(&debug_info->log_mutex);
188
189	return mask;
190}
191
192static int cros_ec_console_log_release(struct inode *inode, struct file *file)
193{
194	return 0;
195}
196
197static ssize_t cros_ec_pdinfo_read(struct file *file,
198				   char __user *user_buf,
199				   size_t count,
200				   loff_t *ppos)
201{
202	char read_buf[EC_USB_PD_MAX_PORTS * 40], *p = read_buf;
203	struct cros_ec_debugfs *debug_info = file->private_data;
204	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
205	struct {
206		struct cros_ec_command msg;
207		union {
208			struct ec_response_usb_pd_control_v1 resp;
209			struct ec_params_usb_pd_control params;
210		};
211	} __packed ec_buf;
212	struct cros_ec_command *msg;
213	struct ec_response_usb_pd_control_v1 *resp;
214	struct ec_params_usb_pd_control *params;
215	int i;
216
217	msg = &ec_buf.msg;
218	params = (struct ec_params_usb_pd_control *)msg->data;
219	resp = (struct ec_response_usb_pd_control_v1 *)msg->data;
220
221	msg->command = EC_CMD_USB_PD_CONTROL;
222	msg->version = 1;
223	msg->insize = sizeof(*resp);
224	msg->outsize = sizeof(*params);
225
226	/*
227	 * Read status from all PD ports until failure, typically caused
228	 * by attempting to read status on a port that doesn't exist.
229	 */
230	for (i = 0; i < EC_USB_PD_MAX_PORTS; ++i) {
231		params->port = i;
232		params->role = 0;
233		params->mux = 0;
234		params->swap = 0;
235
236		if (cros_ec_cmd_xfer_status(ec_dev, msg) < 0)
237			break;
238
239		p += scnprintf(p, sizeof(read_buf) + read_buf - p,
240			       "p%d: %s en:%.2x role:%.2x pol:%.2x\n", i,
241			       resp->state, resp->enabled, resp->role,
242			       resp->polarity);
243	}
244
245	return simple_read_from_buffer(user_buf, count, ppos,
246				       read_buf, p - read_buf);
247}
248
249static bool cros_ec_uptime_is_supported(struct cros_ec_device *ec_dev)
250{
251	struct {
252		struct cros_ec_command cmd;
253		struct ec_response_uptime_info resp;
254	} __packed msg = {};
255	int ret;
256
257	msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
258	msg.cmd.insize = sizeof(msg.resp);
259
260	ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
261	if (ret == -EPROTO && msg.cmd.result == EC_RES_INVALID_COMMAND)
262		return false;
263
264	/* Other errors maybe a transient error, do not rule about support. */
265	return true;
266}
267
268static ssize_t cros_ec_uptime_read(struct file *file, char __user *user_buf,
269				   size_t count, loff_t *ppos)
270{
271	struct cros_ec_debugfs *debug_info = file->private_data;
272	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
273	struct {
274		struct cros_ec_command cmd;
275		struct ec_response_uptime_info resp;
276	} __packed msg = {};
277	struct ec_response_uptime_info *resp;
278	char read_buf[32];
279	int ret;
280
281	resp = (struct ec_response_uptime_info *)&msg.resp;
282
283	msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
284	msg.cmd.insize = sizeof(*resp);
285
286	ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
287	if (ret < 0)
288		return ret;
289
290	ret = scnprintf(read_buf, sizeof(read_buf), "%u\n",
291			resp->time_since_ec_boot_ms);
292
293	return simple_read_from_buffer(user_buf, count, ppos, read_buf, ret);
294}
295
296static const struct file_operations cros_ec_console_log_fops = {
297	.owner = THIS_MODULE,
298	.open = cros_ec_console_log_open,
299	.read = cros_ec_console_log_read,
300	.llseek = no_llseek,
301	.poll = cros_ec_console_log_poll,
302	.release = cros_ec_console_log_release,
303};
304
305static const struct file_operations cros_ec_pdinfo_fops = {
306	.owner = THIS_MODULE,
307	.open = simple_open,
308	.read = cros_ec_pdinfo_read,
309	.llseek = default_llseek,
310};
311
312static const struct file_operations cros_ec_uptime_fops = {
313	.owner = THIS_MODULE,
314	.open = simple_open,
315	.read = cros_ec_uptime_read,
316	.llseek = default_llseek,
317};
318
319static int ec_read_version_supported(struct cros_ec_dev *ec)
320{
321	struct ec_params_get_cmd_versions_v1 *params;
322	struct ec_response_get_cmd_versions *response;
323	int ret;
324
325	struct cros_ec_command *msg;
326
327	msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
328		GFP_KERNEL);
329	if (!msg)
330		return 0;
331
332	msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
333	msg->outsize = sizeof(*params);
334	msg->insize = sizeof(*response);
335
336	params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
337	params->cmd = EC_CMD_CONSOLE_READ;
338	response = (struct ec_response_get_cmd_versions *)msg->data;
339
340	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg) >= 0 &&
341	      response->version_mask & EC_VER_MASK(1);
342
343	kfree(msg);
344
345	return ret;
346}
347
348static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
349{
350	struct cros_ec_dev *ec = debug_info->ec;
351	char *buf;
352	int read_params_size;
353	int read_response_size;
354
355	/*
356	 * If the console log feature is not supported return silently and
357	 * don't create the console_log entry.
358	 */
359	if (!ec_read_version_supported(ec))
360		return 0;
361
362	buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
363	if (!buf)
364		return -ENOMEM;
365
366	read_params_size = sizeof(struct ec_params_console_read_v1);
367	read_response_size = ec->ec_dev->max_response;
368	debug_info->read_msg = devm_kzalloc(ec->dev,
369		sizeof(*debug_info->read_msg) +
370			max(read_params_size, read_response_size), GFP_KERNEL);
371	if (!debug_info->read_msg)
372		return -ENOMEM;
373
374	debug_info->read_msg->version = 1;
375	debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
376	debug_info->read_msg->outsize = read_params_size;
377	debug_info->read_msg->insize = read_response_size;
378
379	debug_info->log_buffer.buf = buf;
380	debug_info->log_buffer.head = 0;
381	debug_info->log_buffer.tail = 0;
382
383	mutex_init(&debug_info->log_mutex);
384
385	debugfs_create_file("console_log", S_IFREG | 0444, debug_info->dir,
386			    debug_info, &cros_ec_console_log_fops);
387
388	INIT_DELAYED_WORK(&debug_info->log_poll_work,
389			  cros_ec_console_log_work);
390	schedule_delayed_work(&debug_info->log_poll_work, 0);
391
392	return 0;
393}
394
395static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
396{
397	if (debug_info->log_buffer.buf) {
398		cancel_delayed_work_sync(&debug_info->log_poll_work);
399		mutex_destroy(&debug_info->log_mutex);
400	}
401}
402
403/*
404 * Returns the size of the panicinfo data fetched from the EC
405 */
406static int cros_ec_get_panicinfo(struct cros_ec_device *ec_dev, uint8_t *data,
407				 int data_size)
408{
409	int ret;
410	struct cros_ec_command *msg;
411
412	if (!data || data_size <= 0 || data_size > ec_dev->max_response)
413		return -EINVAL;
414
415	msg = kzalloc(sizeof(*msg) + data_size, GFP_KERNEL);
416	if (!msg)
417		return -ENOMEM;
418
419	msg->command = EC_CMD_GET_PANIC_INFO;
420	msg->insize = data_size;
421
422	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
423	if (ret < 0)
424		goto free;
425
426	memcpy(data, msg->data, data_size);
427
428free:
429	kfree(msg);
430	return ret;
431}
432
433static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
434{
435	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
436	int ret;
437	void *data;
438
439	data = devm_kzalloc(debug_info->ec->dev, ec_dev->max_response,
440			    GFP_KERNEL);
441	if (!data)
442		return -ENOMEM;
443
444	ret = cros_ec_get_panicinfo(ec_dev, data, ec_dev->max_response);
445	if (ret < 0) {
446		ret = 0;
447		goto free;
448	}
449
450	/* No panic data */
451	if (ret == 0)
452		goto free;
453
454	debug_info->panicinfo_blob.data = data;
455	debug_info->panicinfo_blob.size = ret;
456
457	debugfs_create_blob("panicinfo", 0444, debug_info->dir,
458			    &debug_info->panicinfo_blob);
459
460	return 0;
461
462free:
463	devm_kfree(debug_info->ec->dev, data);
464	return ret;
465}
466
467static int cros_ec_debugfs_panic_event(struct notifier_block *nb,
468				       unsigned long queued_during_suspend, void *_notify)
469{
470	struct cros_ec_debugfs *debug_info =
471		container_of(nb, struct cros_ec_debugfs, notifier_panic);
472
473	if (debug_info->log_buffer.buf) {
474		/* Force log poll work to run immediately */
475		mod_delayed_work(debug_info->log_poll_work.wq, &debug_info->log_poll_work, 0);
476		/* Block until log poll work finishes */
477		flush_delayed_work(&debug_info->log_poll_work);
478	}
479
480	return NOTIFY_DONE;
481}
482
483static int cros_ec_debugfs_probe(struct platform_device *pd)
484{
485	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
486	struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
487	const char *name = ec_platform->ec_name;
488	struct cros_ec_debugfs *debug_info;
489	int ret;
490
491	debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
492	if (!debug_info)
493		return -ENOMEM;
494
495	debug_info->ec = ec;
496	debug_info->dir = debugfs_create_dir(name, NULL);
497
498	ret = cros_ec_create_panicinfo(debug_info);
499	if (ret)
500		goto remove_debugfs;
501
502	ret = cros_ec_create_console_log(debug_info);
503	if (ret)
504		goto remove_debugfs;
505
506	debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
507			    &cros_ec_pdinfo_fops);
508
509	if (cros_ec_uptime_is_supported(ec->ec_dev))
510		debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
511				    &cros_ec_uptime_fops);
512
513	debugfs_create_x32("last_resume_result", 0444, debug_info->dir,
514			   &ec->ec_dev->last_resume_result);
515
516	debugfs_create_u16("suspend_timeout_ms", 0664, debug_info->dir,
517			   &ec->ec_dev->suspend_timeout_ms);
518
519	debug_info->notifier_panic.notifier_call = cros_ec_debugfs_panic_event;
520	ret = blocking_notifier_chain_register(&ec->ec_dev->panic_notifier,
521					       &debug_info->notifier_panic);
522	if (ret)
523		goto remove_debugfs;
524
525	ec->debug_info = debug_info;
526
527	dev_set_drvdata(&pd->dev, ec);
528
529	return 0;
530
531remove_debugfs:
532	debugfs_remove_recursive(debug_info->dir);
533	return ret;
534}
535
536static void cros_ec_debugfs_remove(struct platform_device *pd)
537{
538	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
539
540	debugfs_remove_recursive(ec->debug_info->dir);
541	cros_ec_cleanup_console_log(ec->debug_info);
542}
543
544static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
545{
546	struct cros_ec_dev *ec = dev_get_drvdata(dev);
547
548	if (ec->debug_info->log_buffer.buf)
549		cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
550
551	return 0;
552}
553
554static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
555{
556	struct cros_ec_dev *ec = dev_get_drvdata(dev);
557
558	if (ec->debug_info->log_buffer.buf)
559		schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
560
561	return 0;
562}
563
564static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
565			 cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
566
567static struct platform_driver cros_ec_debugfs_driver = {
568	.driver = {
569		.name = DRV_NAME,
570		.pm = &cros_ec_debugfs_pm_ops,
571		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
572	},
573	.probe = cros_ec_debugfs_probe,
574	.remove_new = cros_ec_debugfs_remove,
575};
576
577module_platform_driver(cros_ec_debugfs_driver);
578
579MODULE_LICENSE("GPL");
580MODULE_DESCRIPTION("Debug logs for ChromeOS EC");
581MODULE_ALIAS("platform:" DRV_NAME);