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/mfd/cros_ec.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
 29/**
 30 * struct cros_ec_debugfs - EC debugging information.
 31 *
 32 * @ec: EC device this debugfs information belongs to
 33 * @dir: dentry for debugfs files
 34 * @log_buffer: circular buffer for console log information
 35 * @read_msg: preallocated EC command and buffer to read console log
 36 * @log_mutex: mutex to protect circular buffer
 37 * @log_wq: waitqueue for log readers
 38 * @log_poll_work: recurring task to poll EC for new console log data
 39 * @panicinfo_blob: panicinfo debugfs blob
 40 */
 41struct cros_ec_debugfs {
 42	struct cros_ec_dev *ec;
 43	struct dentry *dir;
 44	/* EC log */
 45	struct circ_buf log_buffer;
 46	struct cros_ec_command *read_msg;
 47	struct mutex log_mutex;
 48	wait_queue_head_t log_wq;
 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(&debug_info->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(debug_info->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, &debug_info->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 ssize_t cros_ec_uptime_read(struct file *file, char __user *user_buf,
247				   size_t count, loff_t *ppos)
248{
249	struct cros_ec_debugfs *debug_info = file->private_data;
250	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
251	struct {
252		struct cros_ec_command cmd;
253		struct ec_response_uptime_info resp;
254	} __packed msg = {};
255	struct ec_response_uptime_info *resp;
256	char read_buf[32];
257	int ret;
258
259	resp = (struct ec_response_uptime_info *)&msg.resp;
260
261	msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
262	msg.cmd.insize = sizeof(*resp);
263
264	ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
265	if (ret < 0)
266		return ret;
267
268	ret = scnprintf(read_buf, sizeof(read_buf), "%u\n",
269			resp->time_since_ec_boot_ms);
270
271	return simple_read_from_buffer(user_buf, count, ppos, read_buf, ret);
272}
273
274static const struct file_operations cros_ec_console_log_fops = {
275	.owner = THIS_MODULE,
276	.open = cros_ec_console_log_open,
277	.read = cros_ec_console_log_read,
278	.llseek = no_llseek,
279	.poll = cros_ec_console_log_poll,
280	.release = cros_ec_console_log_release,
281};
282
283static const struct file_operations cros_ec_pdinfo_fops = {
284	.owner = THIS_MODULE,
285	.open = simple_open,
286	.read = cros_ec_pdinfo_read,
287	.llseek = default_llseek,
288};
289
290static const struct file_operations cros_ec_uptime_fops = {
291	.owner = THIS_MODULE,
292	.open = simple_open,
293	.read = cros_ec_uptime_read,
294	.llseek = default_llseek,
295};
296
297static int ec_read_version_supported(struct cros_ec_dev *ec)
298{
299	struct ec_params_get_cmd_versions_v1 *params;
300	struct ec_response_get_cmd_versions *response;
301	int ret;
302
303	struct cros_ec_command *msg;
304
305	msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
306		GFP_KERNEL);
307	if (!msg)
308		return 0;
309
310	msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
311	msg->outsize = sizeof(*params);
312	msg->insize = sizeof(*response);
313
314	params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
315	params->cmd = EC_CMD_CONSOLE_READ;
316	response = (struct ec_response_get_cmd_versions *)msg->data;
317
318	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg) >= 0 &&
319	      response->version_mask & EC_VER_MASK(1);
320
321	kfree(msg);
322
323	return ret;
324}
325
326static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
327{
328	struct cros_ec_dev *ec = debug_info->ec;
329	char *buf;
330	int read_params_size;
331	int read_response_size;
332
333	/*
334	 * If the console log feature is not supported return silently and
335	 * don't create the console_log entry.
336	 */
337	if (!ec_read_version_supported(ec))
338		return 0;
339
340	buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
341	if (!buf)
342		return -ENOMEM;
343
344	read_params_size = sizeof(struct ec_params_console_read_v1);
345	read_response_size = ec->ec_dev->max_response;
346	debug_info->read_msg = devm_kzalloc(ec->dev,
347		sizeof(*debug_info->read_msg) +
348			max(read_params_size, read_response_size), GFP_KERNEL);
349	if (!debug_info->read_msg)
350		return -ENOMEM;
351
352	debug_info->read_msg->version = 1;
353	debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
354	debug_info->read_msg->outsize = read_params_size;
355	debug_info->read_msg->insize = read_response_size;
356
357	debug_info->log_buffer.buf = buf;
358	debug_info->log_buffer.head = 0;
359	debug_info->log_buffer.tail = 0;
360
361	mutex_init(&debug_info->log_mutex);
362	init_waitqueue_head(&debug_info->log_wq);
363
364	debugfs_create_file("console_log", S_IFREG | 0444, debug_info->dir,
365			    debug_info, &cros_ec_console_log_fops);
366
367	INIT_DELAYED_WORK(&debug_info->log_poll_work,
368			  cros_ec_console_log_work);
369	schedule_delayed_work(&debug_info->log_poll_work, 0);
370
371	return 0;
372}
373
374static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
375{
376	if (debug_info->log_buffer.buf) {
377		cancel_delayed_work_sync(&debug_info->log_poll_work);
378		mutex_destroy(&debug_info->log_mutex);
379	}
380}
381
382static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
383{
384	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
385	int ret;
386	struct cros_ec_command *msg;
387	int insize;
388
389	insize = ec_dev->max_response;
390
391	msg = devm_kzalloc(debug_info->ec->dev,
392			sizeof(*msg) + insize, GFP_KERNEL);
393	if (!msg)
394		return -ENOMEM;
395
396	msg->command = EC_CMD_GET_PANIC_INFO;
397	msg->insize = insize;
398
399	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
400	if (ret < 0) {
401		ret = 0;
402		goto free;
403	}
404
405	/* No panic data */
406	if (ret == 0)
407		goto free;
408
409	debug_info->panicinfo_blob.data = msg->data;
410	debug_info->panicinfo_blob.size = ret;
411
412	debugfs_create_blob("panicinfo", S_IFREG | 0444, debug_info->dir,
413			    &debug_info->panicinfo_blob);
414
415	return 0;
416
417free:
418	devm_kfree(debug_info->ec->dev, msg);
419	return ret;
420}
421
422static int cros_ec_debugfs_probe(struct platform_device *pd)
423{
424	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
425	struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
426	const char *name = ec_platform->ec_name;
427	struct cros_ec_debugfs *debug_info;
428	int ret;
429
430	debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
431	if (!debug_info)
432		return -ENOMEM;
433
434	debug_info->ec = ec;
435	debug_info->dir = debugfs_create_dir(name, NULL);
436
437	ret = cros_ec_create_panicinfo(debug_info);
438	if (ret)
439		goto remove_debugfs;
440
441	ret = cros_ec_create_console_log(debug_info);
442	if (ret)
443		goto remove_debugfs;
444
445	debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
446			    &cros_ec_pdinfo_fops);
447
448	debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
449			    &cros_ec_uptime_fops);
450
451	debugfs_create_x32("last_resume_result", 0444, debug_info->dir,
452			   &ec->ec_dev->last_resume_result);
453
454	ec->debug_info = debug_info;
455
456	dev_set_drvdata(&pd->dev, ec);
457
458	return 0;
459
460remove_debugfs:
461	debugfs_remove_recursive(debug_info->dir);
462	return ret;
463}
464
465static int cros_ec_debugfs_remove(struct platform_device *pd)
466{
467	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
468
469	debugfs_remove_recursive(ec->debug_info->dir);
470	cros_ec_cleanup_console_log(ec->debug_info);
471
472	return 0;
473}
474
475static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
476{
477	struct cros_ec_dev *ec = dev_get_drvdata(dev);
478
479	if (ec->debug_info->log_buffer.buf)
480		cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
481
482	return 0;
483}
484
485static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
486{
487	struct cros_ec_dev *ec = dev_get_drvdata(dev);
488
489	if (ec->debug_info->log_buffer.buf)
490		schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
491
492	return 0;
493}
494
495static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
496			 cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
497
498static struct platform_driver cros_ec_debugfs_driver = {
499	.driver = {
500		.name = DRV_NAME,
501		.pm = &cros_ec_debugfs_pm_ops,
502	},
503	.probe = cros_ec_debugfs_probe,
504	.remove = cros_ec_debugfs_remove,
505};
506
507module_platform_driver(cros_ec_debugfs_driver);
508
509MODULE_LICENSE("GPL");
510MODULE_DESCRIPTION("Debug logs for ChromeOS EC");
511MODULE_ALIAS("platform:" DRV_NAME);