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/**
 29 * struct cros_ec_debugfs - EC debugging information.
 30 *
 31 * @ec: EC device this debugfs information belongs to
 32 * @dir: dentry for debugfs files
 33 * @log_buffer: circular buffer for console log information
 34 * @read_msg: preallocated EC command and buffer to read console log
 35 * @log_mutex: mutex to protect circular buffer
 36 * @log_wq: waitqueue for log readers
 37 * @log_poll_work: recurring task to poll EC for new console log data
 38 * @panicinfo_blob: panicinfo debugfs blob
 39 */
 40struct cros_ec_debugfs {
 41	struct cros_ec_dev *ec;
 42	struct dentry *dir;
 43	/* EC log */
 44	struct circ_buf log_buffer;
 45	struct cros_ec_command *read_msg;
 46	struct mutex log_mutex;
 47	wait_queue_head_t log_wq;
 48	struct delayed_work log_poll_work;
 49	/* EC panicinfo */
 50	struct debugfs_blob_wrapper panicinfo_blob;
 51};
 52
 53/*
 54 * We need to make sure that the EC log buffer on the UART is large enough,
 55 * so that it is unlikely enough to overlow within LOG_POLL_SEC.
 56 */
 57static void cros_ec_console_log_work(struct work_struct *__work)
 58{
 59	struct cros_ec_debugfs *debug_info =
 60		container_of(to_delayed_work(__work),
 61			     struct cros_ec_debugfs,
 62			     log_poll_work);
 63	struct cros_ec_dev *ec = debug_info->ec;
 64	struct circ_buf *cb = &debug_info->log_buffer;
 65	struct cros_ec_command snapshot_msg = {
 66		.command = EC_CMD_CONSOLE_SNAPSHOT + ec->cmd_offset,
 67	};
 68
 69	struct ec_params_console_read_v1 *read_params =
 70		(struct ec_params_console_read_v1 *)debug_info->read_msg->data;
 71	uint8_t *ec_buffer = (uint8_t *)debug_info->read_msg->data;
 72	int idx;
 73	int buf_space;
 74	int ret;
 75
 76	ret = cros_ec_cmd_xfer_status(ec->ec_dev, &snapshot_msg);
 77	if (ret < 0)
 78		goto resched;
 79
 80	/* Loop until we have read everything, or there's an error. */
 81	mutex_lock(&debug_info->log_mutex);
 82	buf_space = CIRC_SPACE(cb->head, cb->tail, LOG_SIZE);
 83
 84	while (1) {
 85		if (!buf_space) {
 86			dev_info_once(ec->dev,
 87				      "Some logs may have been dropped...\n");
 88			break;
 89		}
 90
 91		memset(read_params, '\0', sizeof(*read_params));
 92		read_params->subcmd = CONSOLE_READ_RECENT;
 93		ret = cros_ec_cmd_xfer_status(ec->ec_dev,
 94					      debug_info->read_msg);
 95		if (ret < 0)
 96			break;
 97
 98		/* If the buffer is empty, we're done here. */
 99		if (ret == 0 || ec_buffer[0] == '\0')
100			break;
101
102		idx = 0;
103		while (idx < ret && ec_buffer[idx] != '\0' && buf_space > 0) {
104			cb->buf[cb->head] = ec_buffer[idx];
105			cb->head = CIRC_ADD(cb->head, LOG_SIZE, 1);
106			idx++;
107			buf_space--;
108		}
109
110		wake_up(&debug_info->log_wq);
111	}
112
113	mutex_unlock(&debug_info->log_mutex);
114
115resched:
116	schedule_delayed_work(&debug_info->log_poll_work,
117			      msecs_to_jiffies(LOG_POLL_SEC * 1000));
118}
119
120static int cros_ec_console_log_open(struct inode *inode, struct file *file)
121{
122	file->private_data = inode->i_private;
123
124	return stream_open(inode, file);
125}
126
127static ssize_t cros_ec_console_log_read(struct file *file, char __user *buf,
128					size_t count, loff_t *ppos)
129{
130	struct cros_ec_debugfs *debug_info = file->private_data;
131	struct circ_buf *cb = &debug_info->log_buffer;
132	ssize_t ret;
133
134	mutex_lock(&debug_info->log_mutex);
135
136	while (!CIRC_CNT(cb->head, cb->tail, LOG_SIZE)) {
137		if (file->f_flags & O_NONBLOCK) {
138			ret = -EAGAIN;
139			goto error;
140		}
141
142		mutex_unlock(&debug_info->log_mutex);
143
144		ret = wait_event_interruptible(debug_info->log_wq,
145					CIRC_CNT(cb->head, cb->tail, LOG_SIZE));
146		if (ret < 0)
147			return ret;
148
149		mutex_lock(&debug_info->log_mutex);
150	}
151
152	/* Only copy until the end of the circular buffer, and let userspace
153	 * retry to get the rest of the data.
154	 */
155	ret = min_t(size_t, CIRC_CNT_TO_END(cb->head, cb->tail, LOG_SIZE),
156		    count);
157
158	if (copy_to_user(buf, cb->buf + cb->tail, ret)) {
159		ret = -EFAULT;
160		goto error;
161	}
162
163	cb->tail = CIRC_ADD(cb->tail, LOG_SIZE, ret);
164
165error:
166	mutex_unlock(&debug_info->log_mutex);
167	return ret;
168}
169
170static __poll_t cros_ec_console_log_poll(struct file *file,
171					     poll_table *wait)
172{
173	struct cros_ec_debugfs *debug_info = file->private_data;
174	__poll_t mask = 0;
175
176	poll_wait(file, &debug_info->log_wq, wait);
177
178	mutex_lock(&debug_info->log_mutex);
179	if (CIRC_CNT(debug_info->log_buffer.head,
180		     debug_info->log_buffer.tail,
181		     LOG_SIZE))
182		mask |= EPOLLIN | EPOLLRDNORM;
183	mutex_unlock(&debug_info->log_mutex);
184
185	return mask;
186}
187
188static int cros_ec_console_log_release(struct inode *inode, struct file *file)
189{
190	return 0;
191}
192
193static ssize_t cros_ec_pdinfo_read(struct file *file,
194				   char __user *user_buf,
195				   size_t count,
196				   loff_t *ppos)
197{
198	char read_buf[EC_USB_PD_MAX_PORTS * 40], *p = read_buf;
199	struct cros_ec_debugfs *debug_info = file->private_data;
200	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
201	struct {
202		struct cros_ec_command msg;
203		union {
204			struct ec_response_usb_pd_control_v1 resp;
205			struct ec_params_usb_pd_control params;
206		};
207	} __packed ec_buf;
208	struct cros_ec_command *msg;
209	struct ec_response_usb_pd_control_v1 *resp;
210	struct ec_params_usb_pd_control *params;
211	int i;
212
213	msg = &ec_buf.msg;
214	params = (struct ec_params_usb_pd_control *)msg->data;
215	resp = (struct ec_response_usb_pd_control_v1 *)msg->data;
216
217	msg->command = EC_CMD_USB_PD_CONTROL;
218	msg->version = 1;
219	msg->insize = sizeof(*resp);
220	msg->outsize = sizeof(*params);
221
222	/*
223	 * Read status from all PD ports until failure, typically caused
224	 * by attempting to read status on a port that doesn't exist.
225	 */
226	for (i = 0; i < EC_USB_PD_MAX_PORTS; ++i) {
227		params->port = i;
228		params->role = 0;
229		params->mux = 0;
230		params->swap = 0;
231
232		if (cros_ec_cmd_xfer_status(ec_dev, msg) < 0)
233			break;
234
235		p += scnprintf(p, sizeof(read_buf) + read_buf - p,
236			       "p%d: %s en:%.2x role:%.2x pol:%.2x\n", i,
237			       resp->state, resp->enabled, resp->role,
238			       resp->polarity);
239	}
240
241	return simple_read_from_buffer(user_buf, count, ppos,
242				       read_buf, p - read_buf);
243}
244
245static bool cros_ec_uptime_is_supported(struct cros_ec_device *ec_dev)
246{
247	struct {
248		struct cros_ec_command cmd;
249		struct ec_response_uptime_info resp;
250	} __packed msg = {};
251	int ret;
252
253	msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
254	msg.cmd.insize = sizeof(msg.resp);
255
256	ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
257	if (ret == -EPROTO && msg.cmd.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	struct {
270		struct cros_ec_command cmd;
271		struct ec_response_uptime_info resp;
272	} __packed msg = {};
273	struct ec_response_uptime_info *resp;
274	char read_buf[32];
275	int ret;
276
277	resp = (struct ec_response_uptime_info *)&msg.resp;
278
279	msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
280	msg.cmd.insize = sizeof(*resp);
281
282	ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
283	if (ret < 0)
284		return ret;
285
286	ret = scnprintf(read_buf, sizeof(read_buf), "%u\n",
287			resp->time_since_ec_boot_ms);
288
289	return simple_read_from_buffer(user_buf, count, ppos, read_buf, ret);
290}
291
292static const struct file_operations cros_ec_console_log_fops = {
293	.owner = THIS_MODULE,
294	.open = cros_ec_console_log_open,
295	.read = cros_ec_console_log_read,
296	.llseek = no_llseek,
297	.poll = cros_ec_console_log_poll,
298	.release = cros_ec_console_log_release,
299};
300
301static const struct file_operations cros_ec_pdinfo_fops = {
302	.owner = THIS_MODULE,
303	.open = simple_open,
304	.read = cros_ec_pdinfo_read,
305	.llseek = default_llseek,
306};
307
308static const struct file_operations cros_ec_uptime_fops = {
309	.owner = THIS_MODULE,
310	.open = simple_open,
311	.read = cros_ec_uptime_read,
312	.llseek = default_llseek,
313};
314
315static int ec_read_version_supported(struct cros_ec_dev *ec)
316{
317	struct ec_params_get_cmd_versions_v1 *params;
318	struct ec_response_get_cmd_versions *response;
319	int ret;
320
321	struct cros_ec_command *msg;
322
323	msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
324		GFP_KERNEL);
325	if (!msg)
326		return 0;
327
328	msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
329	msg->outsize = sizeof(*params);
330	msg->insize = sizeof(*response);
331
332	params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
333	params->cmd = EC_CMD_CONSOLE_READ;
334	response = (struct ec_response_get_cmd_versions *)msg->data;
335
336	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg) >= 0 &&
337	      response->version_mask & EC_VER_MASK(1);
338
339	kfree(msg);
340
341	return ret;
342}
343
344static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
345{
346	struct cros_ec_dev *ec = debug_info->ec;
347	char *buf;
348	int read_params_size;
349	int read_response_size;
350
351	/*
352	 * If the console log feature is not supported return silently and
353	 * don't create the console_log entry.
354	 */
355	if (!ec_read_version_supported(ec))
356		return 0;
357
358	buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
359	if (!buf)
360		return -ENOMEM;
361
362	read_params_size = sizeof(struct ec_params_console_read_v1);
363	read_response_size = ec->ec_dev->max_response;
364	debug_info->read_msg = devm_kzalloc(ec->dev,
365		sizeof(*debug_info->read_msg) +
366			max(read_params_size, read_response_size), GFP_KERNEL);
367	if (!debug_info->read_msg)
368		return -ENOMEM;
369
370	debug_info->read_msg->version = 1;
371	debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
372	debug_info->read_msg->outsize = read_params_size;
373	debug_info->read_msg->insize = read_response_size;
374
375	debug_info->log_buffer.buf = buf;
376	debug_info->log_buffer.head = 0;
377	debug_info->log_buffer.tail = 0;
378
379	mutex_init(&debug_info->log_mutex);
380	init_waitqueue_head(&debug_info->log_wq);
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	ec->debug_info = debug_info;
474
475	dev_set_drvdata(&pd->dev, ec);
476
477	return 0;
478
479remove_debugfs:
480	debugfs_remove_recursive(debug_info->dir);
481	return ret;
482}
483
484static 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
494static 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
504static 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
514static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
515			 cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
516
517static 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
526module_platform_driver(cros_ec_debugfs_driver);
527
528MODULE_LICENSE("GPL");
529MODULE_DESCRIPTION("Debug logs for ChromeOS EC");
530MODULE_ALIAS("platform:" DRV_NAME);