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 */
29 static 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 */
44 struct 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 */
cros_ec_console_log_work(struct work_struct * __work)61 static 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
119 resched:
120 schedule_delayed_work(&debug_info->log_poll_work,
121 msecs_to_jiffies(LOG_POLL_SEC * 1000));
122 }
123
cros_ec_console_log_open(struct inode * inode,struct file * file)124 static 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
cros_ec_console_log_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)131 static 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
169 error:
170 mutex_unlock(&debug_info->log_mutex);
171 return ret;
172 }
173
cros_ec_console_log_poll(struct file * file,poll_table * wait)174 static __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
cros_ec_console_log_release(struct inode * inode,struct file * file)192 static int cros_ec_console_log_release(struct inode *inode, struct file *file)
193 {
194 return 0;
195 }
196
cros_ec_pdinfo_read(struct file * file,char __user * user_buf,size_t count,loff_t * ppos)197 static 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
cros_ec_uptime_is_supported(struct cros_ec_device * ec_dev)249 static 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
cros_ec_uptime_read(struct file * file,char __user * user_buf,size_t count,loff_t * ppos)268 static 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
296 static 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
305 static 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
312 static 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
ec_read_version_supported(struct cros_ec_dev * ec)319 static 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->version = 1;
333 msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
334 msg->outsize = sizeof(*params);
335 msg->insize = sizeof(*response);
336
337 params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
338 params->cmd = EC_CMD_CONSOLE_READ;
339 response = (struct ec_response_get_cmd_versions *)msg->data;
340
341 ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg) >= 0 &&
342 response->version_mask & EC_VER_MASK(1);
343
344 kfree(msg);
345
346 return ret;
347 }
348
cros_ec_create_console_log(struct cros_ec_debugfs * debug_info)349 static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
350 {
351 struct cros_ec_dev *ec = debug_info->ec;
352 char *buf;
353 int read_params_size;
354 int read_response_size;
355
356 /*
357 * If the console log feature is not supported return silently and
358 * don't create the console_log entry.
359 */
360 if (!ec_read_version_supported(ec))
361 return 0;
362
363 buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
364 if (!buf)
365 return -ENOMEM;
366
367 read_params_size = sizeof(struct ec_params_console_read_v1);
368 read_response_size = ec->ec_dev->max_response;
369 debug_info->read_msg = devm_kzalloc(ec->dev,
370 sizeof(*debug_info->read_msg) +
371 max(read_params_size, read_response_size), GFP_KERNEL);
372 if (!debug_info->read_msg)
373 return -ENOMEM;
374
375 debug_info->read_msg->version = 1;
376 debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
377 debug_info->read_msg->outsize = read_params_size;
378 debug_info->read_msg->insize = read_response_size;
379
380 debug_info->log_buffer.buf = buf;
381 debug_info->log_buffer.head = 0;
382 debug_info->log_buffer.tail = 0;
383
384 mutex_init(&debug_info->log_mutex);
385
386 debugfs_create_file("console_log", S_IFREG | 0444, debug_info->dir,
387 debug_info, &cros_ec_console_log_fops);
388
389 INIT_DELAYED_WORK(&debug_info->log_poll_work,
390 cros_ec_console_log_work);
391 schedule_delayed_work(&debug_info->log_poll_work, 0);
392
393 return 0;
394 }
395
cros_ec_cleanup_console_log(struct cros_ec_debugfs * debug_info)396 static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
397 {
398 if (debug_info->log_buffer.buf) {
399 cancel_delayed_work_sync(&debug_info->log_poll_work);
400 mutex_destroy(&debug_info->log_mutex);
401 }
402 }
403
404 /*
405 * Returns the size of the panicinfo data fetched from the EC
406 */
cros_ec_get_panicinfo(struct cros_ec_device * ec_dev,uint8_t * data,int data_size)407 static int cros_ec_get_panicinfo(struct cros_ec_device *ec_dev, uint8_t *data,
408 int data_size)
409 {
410 int ret;
411 struct cros_ec_command *msg;
412
413 if (!data || data_size <= 0 || data_size > ec_dev->max_response)
414 return -EINVAL;
415
416 msg = kzalloc(sizeof(*msg) + data_size, GFP_KERNEL);
417 if (!msg)
418 return -ENOMEM;
419
420 msg->command = EC_CMD_GET_PANIC_INFO;
421 msg->insize = data_size;
422
423 ret = cros_ec_cmd_xfer_status(ec_dev, msg);
424 if (ret < 0)
425 goto free;
426
427 memcpy(data, msg->data, data_size);
428
429 free:
430 kfree(msg);
431 return ret;
432 }
433
cros_ec_create_panicinfo(struct cros_ec_debugfs * debug_info)434 static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
435 {
436 struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
437 int ret;
438 void *data;
439
440 data = devm_kzalloc(debug_info->ec->dev, ec_dev->max_response,
441 GFP_KERNEL);
442 if (!data)
443 return -ENOMEM;
444
445 ret = cros_ec_get_panicinfo(ec_dev, data, ec_dev->max_response);
446 if (ret < 0) {
447 ret = 0;
448 goto free;
449 }
450
451 /* No panic data */
452 if (ret == 0)
453 goto free;
454
455 debug_info->panicinfo_blob.data = data;
456 debug_info->panicinfo_blob.size = ret;
457
458 debugfs_create_blob("panicinfo", S_IFREG | 0444, debug_info->dir,
459 &debug_info->panicinfo_blob);
460
461 return 0;
462
463 free:
464 devm_kfree(debug_info->ec->dev, data);
465 return ret;
466 }
467
cros_ec_debugfs_panic_event(struct notifier_block * nb,unsigned long queued_during_suspend,void * _notify)468 static int cros_ec_debugfs_panic_event(struct notifier_block *nb,
469 unsigned long queued_during_suspend, void *_notify)
470 {
471 struct cros_ec_debugfs *debug_info =
472 container_of(nb, struct cros_ec_debugfs, notifier_panic);
473
474 if (debug_info->log_buffer.buf) {
475 /* Force log poll work to run immediately */
476 mod_delayed_work(debug_info->log_poll_work.wq, &debug_info->log_poll_work, 0);
477 /* Block until log poll work finishes */
478 flush_delayed_work(&debug_info->log_poll_work);
479 }
480
481 return NOTIFY_DONE;
482 }
483
cros_ec_debugfs_probe(struct platform_device * pd)484 static int cros_ec_debugfs_probe(struct platform_device *pd)
485 {
486 struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
487 struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
488 const char *name = ec_platform->ec_name;
489 struct cros_ec_debugfs *debug_info;
490 int ret;
491
492 debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
493 if (!debug_info)
494 return -ENOMEM;
495
496 debug_info->ec = ec;
497 debug_info->dir = debugfs_create_dir(name, NULL);
498
499 ret = cros_ec_create_panicinfo(debug_info);
500 if (ret)
501 goto remove_debugfs;
502
503 ret = cros_ec_create_console_log(debug_info);
504 if (ret)
505 goto remove_debugfs;
506
507 debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
508 &cros_ec_pdinfo_fops);
509
510 if (cros_ec_uptime_is_supported(ec->ec_dev))
511 debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
512 &cros_ec_uptime_fops);
513
514 debugfs_create_x32("last_resume_result", 0444, debug_info->dir,
515 &ec->ec_dev->last_resume_result);
516
517 debugfs_create_u16("suspend_timeout_ms", 0664, debug_info->dir,
518 &ec->ec_dev->suspend_timeout_ms);
519
520 debug_info->notifier_panic.notifier_call = cros_ec_debugfs_panic_event;
521 ret = blocking_notifier_chain_register(&ec->ec_dev->panic_notifier,
522 &debug_info->notifier_panic);
523 if (ret)
524 goto remove_debugfs;
525
526 ec->debug_info = debug_info;
527
528 dev_set_drvdata(&pd->dev, ec);
529
530 return 0;
531
532 remove_debugfs:
533 debugfs_remove_recursive(debug_info->dir);
534 return ret;
535 }
536
cros_ec_debugfs_remove(struct platform_device * pd)537 static int cros_ec_debugfs_remove(struct platform_device *pd)
538 {
539 struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
540
541 debugfs_remove_recursive(ec->debug_info->dir);
542 cros_ec_cleanup_console_log(ec->debug_info);
543
544 return 0;
545 }
546
cros_ec_debugfs_suspend(struct device * dev)547 static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
548 {
549 struct cros_ec_dev *ec = dev_get_drvdata(dev);
550
551 if (ec->debug_info->log_buffer.buf)
552 cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
553
554 return 0;
555 }
556
cros_ec_debugfs_resume(struct device * dev)557 static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
558 {
559 struct cros_ec_dev *ec = dev_get_drvdata(dev);
560
561 if (ec->debug_info->log_buffer.buf)
562 schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
563
564 return 0;
565 }
566
567 static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
568 cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
569
570 static struct platform_driver cros_ec_debugfs_driver = {
571 .driver = {
572 .name = DRV_NAME,
573 .pm = &cros_ec_debugfs_pm_ops,
574 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
575 },
576 .probe = cros_ec_debugfs_probe,
577 .remove = cros_ec_debugfs_remove,
578 };
579
580 module_platform_driver(cros_ec_debugfs_driver);
581
582 MODULE_LICENSE("GPL");
583 MODULE_DESCRIPTION("Debug logs for ChromeOS EC");
584 MODULE_ALIAS("platform:" DRV_NAME);
585