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/mod_devicetable.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
29static unsigned int log_poll_period_ms = LOG_POLL_SEC * MSEC_PER_SEC;
30module_param(log_poll_period_ms, uint, 0644);
31MODULE_PARM_DESC(log_poll_period_ms, "EC log polling period(ms)");
32
33/* waitqueue for log readers */
34static DECLARE_WAIT_QUEUE_HEAD(cros_ec_debugfs_log_wq);
35
36/**
37 * struct cros_ec_debugfs - EC debugging information.
38 *
39 * @ec: EC device this debugfs information belongs to
40 * @dir: dentry for debugfs files
41 * @log_buffer: circular buffer for console log information
42 * @read_msg: preallocated EC command and buffer to read console log
43 * @log_mutex: mutex to protect circular buffer
44 * @log_poll_work: recurring task to poll EC for new console log data
45 * @panicinfo_blob: panicinfo debugfs blob
46 * @notifier_panic: notifier_block to let kernel to flush buffered log
47 * when EC panic
48 */
49struct cros_ec_debugfs {
50 struct cros_ec_dev *ec;
51 struct dentry *dir;
52 /* EC log */
53 struct circ_buf log_buffer;
54 struct cros_ec_command *read_msg;
55 struct mutex log_mutex;
56 struct delayed_work log_poll_work;
57 /* EC panicinfo */
58 struct debugfs_blob_wrapper panicinfo_blob;
59 struct notifier_block notifier_panic;
60};
61
62/*
63 * We need to make sure that the EC log buffer on the UART is large enough,
64 * so that it is unlikely enough to overlow within log_poll_period_ms.
65 */
66static void cros_ec_console_log_work(struct work_struct *__work)
67{
68 struct cros_ec_debugfs *debug_info =
69 container_of(to_delayed_work(__work),
70 struct cros_ec_debugfs,
71 log_poll_work);
72 struct cros_ec_dev *ec = debug_info->ec;
73 struct circ_buf *cb = &debug_info->log_buffer;
74 struct cros_ec_command snapshot_msg = {
75 .command = EC_CMD_CONSOLE_SNAPSHOT + ec->cmd_offset,
76 };
77
78 struct ec_params_console_read_v1 *read_params =
79 (struct ec_params_console_read_v1 *)debug_info->read_msg->data;
80 uint8_t *ec_buffer = (uint8_t *)debug_info->read_msg->data;
81 int idx;
82 int buf_space;
83 int ret;
84
85 ret = cros_ec_cmd_xfer_status(ec_dev: ec->ec_dev, msg: &snapshot_msg);
86 if (ret < 0)
87 goto resched;
88
89 /* Loop until we have read everything, or there's an error. */
90 mutex_lock(&debug_info->log_mutex);
91 buf_space = CIRC_SPACE(cb->head, cb->tail, LOG_SIZE);
92
93 while (1) {
94 if (!buf_space) {
95 dev_info_once(ec->dev,
96 "Some logs may have been dropped...\n");
97 break;
98 }
99
100 memset(read_params, '\0', sizeof(*read_params));
101 read_params->subcmd = CONSOLE_READ_RECENT;
102 ret = cros_ec_cmd_xfer_status(ec_dev: ec->ec_dev,
103 msg: debug_info->read_msg);
104 if (ret < 0)
105 break;
106
107 /* If the buffer is empty, we're done here. */
108 if (ret == 0 || ec_buffer[0] == '\0')
109 break;
110
111 idx = 0;
112 while (idx < ret && ec_buffer[idx] != '\0' && buf_space > 0) {
113 cb->buf[cb->head] = ec_buffer[idx];
114 cb->head = CIRC_ADD(cb->head, LOG_SIZE, 1);
115 idx++;
116 buf_space--;
117 }
118
119 wake_up(&cros_ec_debugfs_log_wq);
120 }
121
122 mutex_unlock(lock: &debug_info->log_mutex);
123
124resched:
125 schedule_delayed_work(dwork: &debug_info->log_poll_work,
126 delay: msecs_to_jiffies(m: log_poll_period_ms));
127}
128
129static int cros_ec_console_log_open(struct inode *inode, struct file *file)
130{
131 file->private_data = inode->i_private;
132
133 return stream_open(inode, filp: file);
134}
135
136static ssize_t cros_ec_console_log_read(struct file *file, char __user *buf,
137 size_t count, loff_t *ppos)
138{
139 struct cros_ec_debugfs *debug_info = file->private_data;
140 struct circ_buf *cb = &debug_info->log_buffer;
141 ssize_t ret;
142
143 mutex_lock(&debug_info->log_mutex);
144
145 while (!CIRC_CNT(cb->head, cb->tail, LOG_SIZE)) {
146 if (file->f_flags & O_NONBLOCK) {
147 ret = -EAGAIN;
148 goto error;
149 }
150
151 mutex_unlock(lock: &debug_info->log_mutex);
152
153 ret = wait_event_interruptible(cros_ec_debugfs_log_wq,
154 CIRC_CNT(cb->head, cb->tail, LOG_SIZE));
155 if (ret < 0)
156 return ret;
157
158 mutex_lock(&debug_info->log_mutex);
159 }
160
161 /* Only copy until the end of the circular buffer, and let userspace
162 * retry to get the rest of the data.
163 */
164 ret = min_t(size_t, CIRC_CNT_TO_END(cb->head, cb->tail, LOG_SIZE),
165 count);
166
167 if (copy_to_user(to: buf, from: cb->buf + cb->tail, n: ret)) {
168 ret = -EFAULT;
169 goto error;
170 }
171
172 cb->tail = CIRC_ADD(cb->tail, LOG_SIZE, ret);
173
174error:
175 mutex_unlock(lock: &debug_info->log_mutex);
176 return ret;
177}
178
179static __poll_t cros_ec_console_log_poll(struct file *file,
180 poll_table *wait)
181{
182 struct cros_ec_debugfs *debug_info = file->private_data;
183 __poll_t mask = 0;
184
185 poll_wait(filp: file, wait_address: &cros_ec_debugfs_log_wq, p: wait);
186
187 mutex_lock(&debug_info->log_mutex);
188 if (CIRC_CNT(debug_info->log_buffer.head,
189 debug_info->log_buffer.tail,
190 LOG_SIZE))
191 mask |= EPOLLIN | EPOLLRDNORM;
192 mutex_unlock(lock: &debug_info->log_mutex);
193
194 return mask;
195}
196
197static int cros_ec_console_log_release(struct inode *inode, struct file *file)
198{
199 return 0;
200}
201
202static ssize_t cros_ec_pdinfo_read(struct file *file,
203 char __user *user_buf,
204 size_t count,
205 loff_t *ppos)
206{
207 char read_buf[EC_USB_PD_MAX_PORTS * 40], *p = read_buf;
208 struct cros_ec_debugfs *debug_info = file->private_data;
209 struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
210 DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
211 MAX(sizeof(struct ec_response_usb_pd_control_v1),
212 sizeof(struct ec_params_usb_pd_control)));
213 struct ec_response_usb_pd_control_v1 *resp =
214 (struct ec_response_usb_pd_control_v1 *)msg->data;
215 struct ec_params_usb_pd_control *params =
216 (struct ec_params_usb_pd_control *)msg->data;
217 int i;
218
219 msg->command = EC_CMD_USB_PD_CONTROL;
220 msg->version = 1;
221 msg->insize = sizeof(*resp);
222 msg->outsize = sizeof(*params);
223
224 /*
225 * Read status from all PD ports until failure, typically caused
226 * by attempting to read status on a port that doesn't exist.
227 */
228 for (i = 0; i < EC_USB_PD_MAX_PORTS; ++i) {
229 params->port = i;
230 params->role = 0;
231 params->mux = 0;
232 params->swap = 0;
233
234 if (cros_ec_cmd_xfer_status(ec_dev, msg) < 0)
235 break;
236
237 p += scnprintf(buf: p, size: sizeof(read_buf) + read_buf - p,
238 fmt: "p%d: %s en:%.2x role:%.2x pol:%.2x\n", i,
239 resp->state, resp->enabled, resp->role,
240 resp->polarity);
241 }
242
243 return simple_read_from_buffer(to: user_buf, count, ppos,
244 from: read_buf, available: p - read_buf);
245}
246
247static bool cros_ec_uptime_is_supported(struct cros_ec_device *ec_dev)
248{
249 DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
250 sizeof(struct ec_response_uptime_info));
251 int ret;
252
253 msg->command = EC_CMD_GET_UPTIME_INFO;
254 msg->insize = sizeof(struct ec_response_uptime_info);
255
256 ret = cros_ec_cmd_xfer_status(ec_dev, msg);
257 if (ret == -EPROTO && msg->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 DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
270 sizeof(struct ec_response_uptime_info));
271 struct ec_response_uptime_info *resp =
272 (struct ec_response_uptime_info *)msg->data;
273 char read_buf[32];
274 int ret;
275
276 msg->command = EC_CMD_GET_UPTIME_INFO;
277 msg->insize = sizeof(*resp);
278
279 ret = cros_ec_cmd_xfer_status(ec_dev, msg);
280 if (ret < 0)
281 return ret;
282
283 ret = scnprintf(buf: read_buf, size: sizeof(read_buf), fmt: "%u\n",
284 resp->time_since_ec_boot_ms);
285
286 return simple_read_from_buffer(to: user_buf, count, ppos, from: read_buf, available: ret);
287}
288
289static const struct file_operations cros_ec_console_log_fops = {
290 .owner = THIS_MODULE,
291 .open = cros_ec_console_log_open,
292 .read = cros_ec_console_log_read,
293 .poll = cros_ec_console_log_poll,
294 .release = cros_ec_console_log_release,
295};
296
297static const struct file_operations cros_ec_pdinfo_fops = {
298 .owner = THIS_MODULE,
299 .open = simple_open,
300 .read = cros_ec_pdinfo_read,
301 .llseek = default_llseek,
302};
303
304static const struct file_operations cros_ec_uptime_fops = {
305 .owner = THIS_MODULE,
306 .open = simple_open,
307 .read = cros_ec_uptime_read,
308 .llseek = default_llseek,
309};
310
311static int ec_read_version_supported(struct cros_ec_dev *ec)
312{
313 struct ec_params_get_cmd_versions_v1 *params;
314 struct ec_response_get_cmd_versions *response;
315 int ret;
316
317 struct cros_ec_command *msg;
318
319 msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
320 GFP_KERNEL);
321 if (!msg)
322 return 0;
323
324 msg->version = 1;
325 msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
326 msg->outsize = sizeof(*params);
327 msg->insize = sizeof(*response);
328
329 params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
330 params->cmd = EC_CMD_CONSOLE_READ;
331 response = (struct ec_response_get_cmd_versions *)msg->data;
332
333 ret = cros_ec_cmd_xfer_status(ec_dev: ec->ec_dev, msg) >= 0 &&
334 response->version_mask & EC_VER_MASK(1);
335
336 kfree(objp: msg);
337
338 return ret;
339}
340
341static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
342{
343 struct cros_ec_dev *ec = debug_info->ec;
344 char *buf;
345 int read_params_size;
346 int read_response_size;
347
348 /*
349 * If the console log feature is not supported return silently and
350 * don't create the console_log entry.
351 */
352 if (!ec_read_version_supported(ec))
353 return 0;
354
355 buf = devm_kzalloc(dev: ec->dev, LOG_SIZE, GFP_KERNEL);
356 if (!buf)
357 return -ENOMEM;
358
359 read_params_size = sizeof(struct ec_params_console_read_v1);
360 read_response_size = ec->ec_dev->max_response;
361 debug_info->read_msg = devm_kzalloc(dev: ec->dev,
362 size: sizeof(*debug_info->read_msg) +
363 max(read_params_size, read_response_size), GFP_KERNEL);
364 if (!debug_info->read_msg)
365 return -ENOMEM;
366
367 debug_info->read_msg->version = 1;
368 debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
369 debug_info->read_msg->outsize = read_params_size;
370 debug_info->read_msg->insize = read_response_size;
371
372 debug_info->log_buffer.buf = buf;
373 debug_info->log_buffer.head = 0;
374 debug_info->log_buffer.tail = 0;
375
376 mutex_init(&debug_info->log_mutex);
377
378 debugfs_create_file("console_log", S_IFREG | 0444, debug_info->dir,
379 debug_info, &cros_ec_console_log_fops);
380
381 INIT_DELAYED_WORK(&debug_info->log_poll_work,
382 cros_ec_console_log_work);
383 schedule_delayed_work(dwork: &debug_info->log_poll_work, delay: 0);
384
385 return 0;
386}
387
388static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
389{
390 if (debug_info->log_buffer.buf) {
391 cancel_delayed_work_sync(dwork: &debug_info->log_poll_work);
392 mutex_destroy(lock: &debug_info->log_mutex);
393 }
394}
395
396/*
397 * Returns the size of the panicinfo data fetched from the EC
398 */
399static int cros_ec_get_panicinfo(struct cros_ec_device *ec_dev, uint8_t *data,
400 int data_size)
401{
402 int ret;
403 struct cros_ec_command *msg;
404
405 if (!data || data_size <= 0 || data_size > ec_dev->max_response)
406 return -EINVAL;
407
408 msg = kzalloc(sizeof(*msg) + data_size, GFP_KERNEL);
409 if (!msg)
410 return -ENOMEM;
411
412 msg->command = EC_CMD_GET_PANIC_INFO;
413 msg->insize = data_size;
414
415 ret = cros_ec_cmd_xfer_status(ec_dev, msg);
416 if (ret < 0)
417 goto free;
418
419 memcpy(data, msg->data, data_size);
420
421free:
422 kfree(objp: msg);
423 return ret;
424}
425
426static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
427{
428 struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
429 int ret;
430 void *data;
431
432 data = devm_kzalloc(dev: debug_info->ec->dev, size: ec_dev->max_response,
433 GFP_KERNEL);
434 if (!data)
435 return -ENOMEM;
436
437 ret = cros_ec_get_panicinfo(ec_dev, data, data_size: ec_dev->max_response);
438 if (ret < 0) {
439 ret = 0;
440 goto free;
441 }
442
443 /* No panic data */
444 if (ret == 0)
445 goto free;
446
447 debug_info->panicinfo_blob.data = data;
448 debug_info->panicinfo_blob.size = ret;
449
450 debugfs_create_blob(name: "panicinfo", mode: 0444, parent: debug_info->dir,
451 blob: &debug_info->panicinfo_blob);
452
453 return 0;
454
455free:
456 devm_kfree(dev: debug_info->ec->dev, p: data);
457 return ret;
458}
459
460static int cros_ec_debugfs_panic_event(struct notifier_block *nb,
461 unsigned long queued_during_suspend, void *_notify)
462{
463 struct cros_ec_debugfs *debug_info =
464 container_of(nb, struct cros_ec_debugfs, notifier_panic);
465
466 if (debug_info->log_buffer.buf) {
467 /* Force log poll work to run immediately */
468 mod_delayed_work(wq: debug_info->log_poll_work.wq, dwork: &debug_info->log_poll_work, delay: 0);
469 /* Block until log poll work finishes */
470 flush_delayed_work(dwork: &debug_info->log_poll_work);
471 }
472
473 return NOTIFY_DONE;
474}
475
476static int cros_ec_debugfs_probe(struct platform_device *pd)
477{
478 struct cros_ec_dev *ec = dev_get_drvdata(dev: pd->dev.parent);
479 struct cros_ec_platform *ec_platform = dev_get_platdata(dev: ec->dev);
480 const char *name = ec_platform->ec_name;
481 struct cros_ec_debugfs *debug_info;
482 int ret;
483
484 debug_info = devm_kzalloc(dev: ec->dev, size: sizeof(*debug_info), GFP_KERNEL);
485 if (!debug_info)
486 return -ENOMEM;
487
488 debug_info->ec = ec;
489 debug_info->dir = debugfs_create_dir(name, NULL);
490
491 ret = cros_ec_create_panicinfo(debug_info);
492 if (ret)
493 goto remove_debugfs;
494
495 ret = cros_ec_create_console_log(debug_info);
496 if (ret)
497 goto remove_debugfs;
498
499 debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
500 &cros_ec_pdinfo_fops);
501
502 if (cros_ec_uptime_is_supported(ec_dev: ec->ec_dev))
503 debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
504 &cros_ec_uptime_fops);
505
506 debugfs_create_x32(name: "last_resume_result", mode: 0444, parent: debug_info->dir,
507 value: &ec->ec_dev->last_resume_result);
508
509 debugfs_create_u16(name: "suspend_timeout_ms", mode: 0664, parent: debug_info->dir,
510 value: &ec->ec_dev->suspend_timeout_ms);
511
512 debug_info->notifier_panic.notifier_call = cros_ec_debugfs_panic_event;
513 ret = blocking_notifier_chain_register(nh: &ec->ec_dev->panic_notifier,
514 nb: &debug_info->notifier_panic);
515 if (ret)
516 goto remove_debugfs;
517
518 ec->debug_info = debug_info;
519
520 dev_set_drvdata(dev: &pd->dev, data: ec);
521
522 return 0;
523
524remove_debugfs:
525 debugfs_remove_recursive(dentry: debug_info->dir);
526 return ret;
527}
528
529static void cros_ec_debugfs_remove(struct platform_device *pd)
530{
531 struct cros_ec_dev *ec = dev_get_drvdata(dev: pd->dev.parent);
532
533 debugfs_remove_recursive(dentry: ec->debug_info->dir);
534 cros_ec_cleanup_console_log(debug_info: ec->debug_info);
535}
536
537static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
538{
539 struct cros_ec_dev *ec = dev_get_drvdata(dev);
540
541 if (ec->debug_info->log_buffer.buf)
542 cancel_delayed_work_sync(dwork: &ec->debug_info->log_poll_work);
543
544 return 0;
545}
546
547static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
548{
549 struct cros_ec_dev *ec = dev_get_drvdata(dev);
550
551 if (ec->debug_info->log_buffer.buf)
552 schedule_delayed_work(dwork: &ec->debug_info->log_poll_work, delay: 0);
553
554 return 0;
555}
556
557static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
558 cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
559
560static const struct platform_device_id cros_ec_debugfs_id[] = {
561 { DRV_NAME, 0 },
562 {}
563};
564MODULE_DEVICE_TABLE(platform, cros_ec_debugfs_id);
565
566static struct platform_driver cros_ec_debugfs_driver = {
567 .driver = {
568 .name = DRV_NAME,
569 .pm = &cros_ec_debugfs_pm_ops,
570 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
571 },
572 .probe = cros_ec_debugfs_probe,
573 .remove = cros_ec_debugfs_remove,
574 .id_table = cros_ec_debugfs_id,
575};
576
577module_platform_driver(cros_ec_debugfs_driver);
578
579MODULE_LICENSE("GPL");
580MODULE_DESCRIPTION("Debug logs for ChromeOS EC");
581

source code of linux/drivers/platform/chrome/cros_ec_debugfs.c