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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
28static unsigned int log_poll_period_ms = LOG_POLL_SEC * MSEC_PER_SEC;
29module_param(log_poll_period_ms, uint, 0644);
30MODULE_PARM_DESC(log_poll_period_ms, "EC log polling period(ms)");
31
32/* waitqueue for log readers */
33static DECLARE_WAIT_QUEUE_HEAD(cros_ec_debugfs_log_wq);
34
35/**
36 * struct cros_ec_debugfs - EC debugging information.
37 *
38 * @ec: EC device this debugfs information belongs to
39 * @dir: dentry for debugfs files
40 * @log_buffer: circular buffer for console log information
41 * @read_msg: preallocated EC command and buffer to read console log
42 * @log_mutex: mutex to protect circular buffer
43 * @log_poll_work: recurring task to poll EC for new console log data
44 * @panicinfo_blob: panicinfo debugfs blob
45 * @notifier_panic: notifier_block to let kernel to flush buffered log
46 * when EC panic
47 */
48struct cros_ec_debugfs {
49 struct cros_ec_dev *ec;
50 struct dentry *dir;
51 /* EC log */
52 struct circ_buf log_buffer;
53 struct cros_ec_command *read_msg;
54 struct mutex log_mutex;
55 struct delayed_work log_poll_work;
56 /* EC panicinfo */
57 struct debugfs_blob_wrapper panicinfo_blob;
58 struct notifier_block notifier_panic;
59};
60
61/*
62 * We need to make sure that the EC log buffer on the UART is large enough,
63 * so that it is unlikely enough to overlow within log_poll_period_ms.
64 */
65static void cros_ec_console_log_work(struct work_struct *__work)
66{
67 struct cros_ec_debugfs *debug_info =
68 container_of(to_delayed_work(__work),
69 struct cros_ec_debugfs,
70 log_poll_work);
71 struct cros_ec_dev *ec = debug_info->ec;
72 struct circ_buf *cb = &debug_info->log_buffer;
73 struct cros_ec_command snapshot_msg = {
74 .command = EC_CMD_CONSOLE_SNAPSHOT + ec->cmd_offset,
75 };
76
77 struct ec_params_console_read_v1 *read_params =
78 (struct ec_params_console_read_v1 *)debug_info->read_msg->data;
79 uint8_t *ec_buffer = (uint8_t *)debug_info->read_msg->data;
80 int idx;
81 int buf_space;
82 int ret;
83
84 ret = cros_ec_cmd_xfer_status(ec->ec_dev, &snapshot_msg);
85 if (ret < 0)
86 goto resched;
87
88 /* Loop until we have read everything, or there's an error. */
89 mutex_lock(&debug_info->log_mutex);
90 buf_space = CIRC_SPACE(cb->head, cb->tail, LOG_SIZE);
91
92 while (1) {
93 if (!buf_space) {
94 dev_info_once(ec->dev,
95 "Some logs may have been dropped...\n");
96 break;
97 }
98
99 memset(read_params, '\0', sizeof(*read_params));
100 read_params->subcmd = CONSOLE_READ_RECENT;
101 ret = cros_ec_cmd_xfer_status(ec->ec_dev,
102 debug_info->read_msg);
103 if (ret < 0)
104 break;
105
106 /* If the buffer is empty, we're done here. */
107 if (ret == 0 || ec_buffer[0] == '\0')
108 break;
109
110 idx = 0;
111 while (idx < ret && ec_buffer[idx] != '\0' && buf_space > 0) {
112 cb->buf[cb->head] = ec_buffer[idx];
113 cb->head = CIRC_ADD(cb->head, LOG_SIZE, 1);
114 idx++;
115 buf_space--;
116 }
117
118 wake_up(&cros_ec_debugfs_log_wq);
119 }
120
121 mutex_unlock(&debug_info->log_mutex);
122
123resched:
124 schedule_delayed_work(&debug_info->log_poll_work,
125 msecs_to_jiffies(log_poll_period_ms));
126}
127
128static int cros_ec_console_log_open(struct inode *inode, struct file *file)
129{
130 file->private_data = inode->i_private;
131
132 return stream_open(inode, file);
133}
134
135static ssize_t cros_ec_console_log_read(struct file *file, char __user *buf,
136 size_t count, loff_t *ppos)
137{
138 struct cros_ec_debugfs *debug_info = file->private_data;
139 struct circ_buf *cb = &debug_info->log_buffer;
140 ssize_t ret;
141
142 mutex_lock(&debug_info->log_mutex);
143
144 while (!CIRC_CNT(cb->head, cb->tail, LOG_SIZE)) {
145 if (file->f_flags & O_NONBLOCK) {
146 ret = -EAGAIN;
147 goto error;
148 }
149
150 mutex_unlock(&debug_info->log_mutex);
151
152 ret = wait_event_interruptible(cros_ec_debugfs_log_wq,
153 CIRC_CNT(cb->head, cb->tail, LOG_SIZE));
154 if (ret < 0)
155 return ret;
156
157 mutex_lock(&debug_info->log_mutex);
158 }
159
160 /* Only copy until the end of the circular buffer, and let userspace
161 * retry to get the rest of the data.
162 */
163 ret = min_t(size_t, CIRC_CNT_TO_END(cb->head, cb->tail, LOG_SIZE),
164 count);
165
166 if (copy_to_user(buf, cb->buf + cb->tail, ret)) {
167 ret = -EFAULT;
168 goto error;
169 }
170
171 cb->tail = CIRC_ADD(cb->tail, LOG_SIZE, ret);
172
173error:
174 mutex_unlock(&debug_info->log_mutex);
175 return ret;
176}
177
178static __poll_t cros_ec_console_log_poll(struct file *file,
179 poll_table *wait)
180{
181 struct cros_ec_debugfs *debug_info = file->private_data;
182 __poll_t mask = 0;
183
184 poll_wait(file, &cros_ec_debugfs_log_wq, wait);
185
186 mutex_lock(&debug_info->log_mutex);
187 if (CIRC_CNT(debug_info->log_buffer.head,
188 debug_info->log_buffer.tail,
189 LOG_SIZE))
190 mask |= EPOLLIN | EPOLLRDNORM;
191 mutex_unlock(&debug_info->log_mutex);
192
193 return mask;
194}
195
196static int cros_ec_console_log_release(struct inode *inode, struct file *file)
197{
198 return 0;
199}
200
201static ssize_t cros_ec_pdinfo_read(struct file *file,
202 char __user *user_buf,
203 size_t count,
204 loff_t *ppos)
205{
206 char read_buf[EC_USB_PD_MAX_PORTS * 40], *p = read_buf;
207 struct cros_ec_debugfs *debug_info = file->private_data;
208 struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
209 DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
210 MAX(sizeof(struct ec_response_usb_pd_control_v1),
211 sizeof(struct ec_params_usb_pd_control)));
212 struct ec_response_usb_pd_control_v1 *resp =
213 (struct ec_response_usb_pd_control_v1 *)msg->data;
214 struct ec_params_usb_pd_control *params =
215 (struct ec_params_usb_pd_control *)msg->data;
216 int i;
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 bool cros_ec_uptime_is_supported(struct cros_ec_device *ec_dev)
247{
248 DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
249 sizeof(struct ec_response_uptime_info));
250 int ret;
251
252 msg->command = EC_CMD_GET_UPTIME_INFO;
253 msg->insize = sizeof(struct ec_response_uptime_info);
254
255 ret = cros_ec_cmd_xfer_status(ec_dev, msg);
256 if (ret == -EPROTO && msg->result == EC_RES_INVALID_COMMAND)
257 return false;
258
259 /* Other errors maybe a transient error, do not rule about support. */
260 return true;
261}
262
263static ssize_t cros_ec_uptime_read(struct file *file, char __user *user_buf,
264 size_t count, loff_t *ppos)
265{
266 struct cros_ec_debugfs *debug_info = file->private_data;
267 struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
268 DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
269 sizeof(struct ec_response_uptime_info));
270 struct ec_response_uptime_info *resp =
271 (struct ec_response_uptime_info *)msg->data;
272 char read_buf[32];
273 int ret;
274
275 msg->command = EC_CMD_GET_UPTIME_INFO;
276 msg->insize = sizeof(*resp);
277
278 ret = cros_ec_cmd_xfer_status(ec_dev, msg);
279 if (ret < 0)
280 return ret;
281
282 ret = scnprintf(read_buf, sizeof(read_buf), "%u\n",
283 resp->time_since_ec_boot_ms);
284
285 return simple_read_from_buffer(user_buf, count, ppos, read_buf, ret);
286}
287
288static const struct file_operations cros_ec_console_log_fops = {
289 .owner = THIS_MODULE,
290 .open = cros_ec_console_log_open,
291 .read = cros_ec_console_log_read,
292 .poll = cros_ec_console_log_poll,
293 .release = cros_ec_console_log_release,
294};
295
296static const struct file_operations cros_ec_pdinfo_fops = {
297 .owner = THIS_MODULE,
298 .open = simple_open,
299 .read = cros_ec_pdinfo_read,
300 .llseek = default_llseek,
301};
302
303static const struct file_operations cros_ec_uptime_fops = {
304 .owner = THIS_MODULE,
305 .open = simple_open,
306 .read = cros_ec_uptime_read,
307 .llseek = default_llseek,
308};
309
310static int ec_read_version_supported(struct cros_ec_dev *ec)
311{
312 struct ec_params_get_cmd_versions_v1 *params;
313 struct ec_response_get_cmd_versions *response;
314 int ret;
315
316 struct cros_ec_command *msg;
317
318 msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
319 GFP_KERNEL);
320 if (!msg)
321 return 0;
322
323 msg->version = 1;
324 msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
325 msg->outsize = sizeof(*params);
326 msg->insize = sizeof(*response);
327
328 params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
329 params->cmd = EC_CMD_CONSOLE_READ;
330 response = (struct ec_response_get_cmd_versions *)msg->data;
331
332 ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg) >= 0 &&
333 response->version_mask & EC_VER_MASK(1);
334
335 kfree(msg);
336
337 return ret;
338}
339
340static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
341{
342 struct cros_ec_dev *ec = debug_info->ec;
343 char *buf;
344 int read_params_size;
345 int read_response_size;
346
347 /*
348 * If the console log feature is not supported return silently and
349 * don't create the console_log entry.
350 */
351 if (!ec_read_version_supported(ec))
352 return 0;
353
354 buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
355 if (!buf)
356 return -ENOMEM;
357
358 read_params_size = sizeof(struct ec_params_console_read_v1);
359 read_response_size = ec->ec_dev->max_response;
360 debug_info->read_msg = devm_kzalloc(ec->dev,
361 sizeof(*debug_info->read_msg) +
362 max(read_params_size, read_response_size), GFP_KERNEL);
363 if (!debug_info->read_msg)
364 return -ENOMEM;
365
366 debug_info->read_msg->version = 1;
367 debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
368 debug_info->read_msg->outsize = read_params_size;
369 debug_info->read_msg->insize = read_response_size;
370
371 debug_info->log_buffer.buf = buf;
372 debug_info->log_buffer.head = 0;
373 debug_info->log_buffer.tail = 0;
374
375 mutex_init(&debug_info->log_mutex);
376
377 debugfs_create_file("console_log", S_IFREG | 0444, debug_info->dir,
378 debug_info, &cros_ec_console_log_fops);
379
380 INIT_DELAYED_WORK(&debug_info->log_poll_work,
381 cros_ec_console_log_work);
382 schedule_delayed_work(&debug_info->log_poll_work, 0);
383
384 return 0;
385}
386
387static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
388{
389 if (debug_info->log_buffer.buf) {
390 cancel_delayed_work_sync(&debug_info->log_poll_work);
391 mutex_destroy(&debug_info->log_mutex);
392 }
393}
394
395/*
396 * Returns the size of the panicinfo data fetched from the EC
397 */
398static int cros_ec_get_panicinfo(struct cros_ec_device *ec_dev, uint8_t *data,
399 int data_size)
400{
401 int ret;
402 struct cros_ec_command *msg;
403
404 if (!data || data_size <= 0 || data_size > ec_dev->max_response)
405 return -EINVAL;
406
407 msg = kzalloc(sizeof(*msg) + data_size, GFP_KERNEL);
408 if (!msg)
409 return -ENOMEM;
410
411 msg->command = EC_CMD_GET_PANIC_INFO;
412 msg->insize = data_size;
413
414 ret = cros_ec_cmd_xfer_status(ec_dev, msg);
415 if (ret < 0)
416 goto free;
417
418 memcpy(data, msg->data, data_size);
419
420free:
421 kfree(msg);
422 return ret;
423}
424
425static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
426{
427 struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
428 int ret;
429 void *data;
430
431 data = devm_kzalloc(debug_info->ec->dev, ec_dev->max_response,
432 GFP_KERNEL);
433 if (!data)
434 return -ENOMEM;
435
436 ret = cros_ec_get_panicinfo(ec_dev, data, ec_dev->max_response);
437 if (ret < 0) {
438 ret = 0;
439 goto free;
440 }
441
442 /* No panic data */
443 if (ret == 0)
444 goto free;
445
446 debug_info->panicinfo_blob.data = data;
447 debug_info->panicinfo_blob.size = ret;
448
449 debugfs_create_blob("panicinfo", 0444, debug_info->dir,
450 &debug_info->panicinfo_blob);
451
452 return 0;
453
454free:
455 devm_kfree(debug_info->ec->dev, data);
456 return ret;
457}
458
459static int cros_ec_debugfs_panic_event(struct notifier_block *nb,
460 unsigned long queued_during_suspend, void *_notify)
461{
462 struct cros_ec_debugfs *debug_info =
463 container_of(nb, struct cros_ec_debugfs, notifier_panic);
464
465 if (debug_info->log_buffer.buf) {
466 /* Force log poll work to run immediately */
467 mod_delayed_work(debug_info->log_poll_work.wq, &debug_info->log_poll_work, 0);
468 /* Block until log poll work finishes */
469 flush_delayed_work(&debug_info->log_poll_work);
470 }
471
472 return NOTIFY_DONE;
473}
474
475static int cros_ec_debugfs_probe(struct platform_device *pd)
476{
477 struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
478 struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
479 const char *name = ec_platform->ec_name;
480 struct cros_ec_debugfs *debug_info;
481 int ret;
482
483 debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
484 if (!debug_info)
485 return -ENOMEM;
486
487 debug_info->ec = ec;
488 debug_info->dir = debugfs_create_dir(name, NULL);
489
490 ret = cros_ec_create_panicinfo(debug_info);
491 if (ret)
492 goto remove_debugfs;
493
494 ret = cros_ec_create_console_log(debug_info);
495 if (ret)
496 goto remove_debugfs;
497
498 debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
499 &cros_ec_pdinfo_fops);
500
501 if (cros_ec_uptime_is_supported(ec->ec_dev))
502 debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
503 &cros_ec_uptime_fops);
504
505 debugfs_create_x32("last_resume_result", 0444, debug_info->dir,
506 &ec->ec_dev->last_resume_result);
507
508 debugfs_create_u16("suspend_timeout_ms", 0664, debug_info->dir,
509 &ec->ec_dev->suspend_timeout_ms);
510
511 debug_info->notifier_panic.notifier_call = cros_ec_debugfs_panic_event;
512 ret = blocking_notifier_chain_register(&ec->ec_dev->panic_notifier,
513 &debug_info->notifier_panic);
514 if (ret)
515 goto cleanup_console_log;
516
517 ec->debug_info = debug_info;
518
519 dev_set_drvdata(&pd->dev, ec);
520
521 return 0;
522
523cleanup_console_log:
524 cros_ec_cleanup_console_log(debug_info);
525remove_debugfs:
526 debugfs_remove_recursive(debug_info->dir);
527 return ret;
528}
529
530static void cros_ec_debugfs_remove(struct platform_device *pd)
531{
532 struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
533
534 blocking_notifier_chain_unregister(&ec->ec_dev->panic_notifier,
535 &ec->debug_info->notifier_panic);
536 debugfs_remove_recursive(ec->debug_info->dir);
537 cros_ec_cleanup_console_log(ec->debug_info);
538}
539
540static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
541{
542 struct cros_ec_dev *ec = dev_get_drvdata(dev);
543
544 if (ec->debug_info->log_buffer.buf)
545 cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
546
547 return 0;
548}
549
550static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
551{
552 struct cros_ec_dev *ec = dev_get_drvdata(dev);
553
554 if (ec->debug_info->log_buffer.buf)
555 schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
556
557 return 0;
558}
559
560static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
561 cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
562
563static const struct platform_device_id cros_ec_debugfs_id[] = {
564 { .name = DRV_NAME },
565 { }
566};
567MODULE_DEVICE_TABLE(platform, cros_ec_debugfs_id);
568
569static struct platform_driver cros_ec_debugfs_driver = {
570 .driver = {
571 .name = DRV_NAME,
572 .pm = &cros_ec_debugfs_pm_ops,
573 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
574 },
575 .probe = cros_ec_debugfs_probe,
576 .remove = cros_ec_debugfs_remove,
577 .id_table = cros_ec_debugfs_id,
578};
579
580module_platform_driver(cros_ec_debugfs_driver);
581
582MODULE_LICENSE("GPL");
583MODULE_DESCRIPTION("Debug logs for ChromeOS EC");