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 */
29static 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 */
44struct 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 */
61static 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_dev: ec->ec_dev, msg: &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_dev: ec->ec_dev,
98 msg: 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(lock: &debug_info->log_mutex);
118
119resched:
120 schedule_delayed_work(dwork: &debug_info->log_poll_work,
121 delay: msecs_to_jiffies(LOG_POLL_SEC * 1000));
122}
123
124static 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, filp: file);
129}
130
131static 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(lock: &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(to: buf, from: cb->buf + cb->tail, n: ret)) {
163 ret = -EFAULT;
164 goto error;
165 }
166
167 cb->tail = CIRC_ADD(cb->tail, LOG_SIZE, ret);
168
169error:
170 mutex_unlock(lock: &debug_info->log_mutex);
171 return ret;
172}
173
174static __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(filp: file, wait_address: &cros_ec_debugfs_log_wq, p: 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(lock: &debug_info->log_mutex);
188
189 return mask;
190}
191
192static int cros_ec_console_log_release(struct inode *inode, struct file *file)
193{
194 return 0;
195}
196
197static 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(buf: p, size: sizeof(read_buf) + read_buf - p,
240 fmt: "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(to: user_buf, count, ppos,
246 from: read_buf, available: p - read_buf);
247}
248
249static 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: &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
268static 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: &msg.cmd);
287 if (ret < 0)
288 return ret;
289
290 ret = scnprintf(buf: read_buf, size: sizeof(read_buf), fmt: "%u\n",
291 resp->time_since_ec_boot_ms);
292
293 return simple_read_from_buffer(to: user_buf, count, ppos, from: read_buf, available: ret);
294}
295
296static 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
305static 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
312static 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
319static 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(size: sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
328 GFP_KERNEL);
329 if (!msg)
330 return 0;
331
332 msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
333 msg->outsize = sizeof(*params);
334 msg->insize = sizeof(*response);
335
336 params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
337 params->cmd = EC_CMD_CONSOLE_READ;
338 response = (struct ec_response_get_cmd_versions *)msg->data;
339
340 ret = cros_ec_cmd_xfer_status(ec_dev: ec->ec_dev, msg) >= 0 &&
341 response->version_mask & EC_VER_MASK(1);
342
343 kfree(objp: msg);
344
345 return ret;
346}
347
348static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
349{
350 struct cros_ec_dev *ec = debug_info->ec;
351 char *buf;
352 int read_params_size;
353 int read_response_size;
354
355 /*
356 * If the console log feature is not supported return silently and
357 * don't create the console_log entry.
358 */
359 if (!ec_read_version_supported(ec))
360 return 0;
361
362 buf = devm_kzalloc(dev: ec->dev, LOG_SIZE, GFP_KERNEL);
363 if (!buf)
364 return -ENOMEM;
365
366 read_params_size = sizeof(struct ec_params_console_read_v1);
367 read_response_size = ec->ec_dev->max_response;
368 debug_info->read_msg = devm_kzalloc(dev: ec->dev,
369 size: sizeof(*debug_info->read_msg) +
370 max(read_params_size, read_response_size), GFP_KERNEL);
371 if (!debug_info->read_msg)
372 return -ENOMEM;
373
374 debug_info->read_msg->version = 1;
375 debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
376 debug_info->read_msg->outsize = read_params_size;
377 debug_info->read_msg->insize = read_response_size;
378
379 debug_info->log_buffer.buf = buf;
380 debug_info->log_buffer.head = 0;
381 debug_info->log_buffer.tail = 0;
382
383 mutex_init(&debug_info->log_mutex);
384
385 debugfs_create_file(name: "console_log", S_IFREG | 0444, parent: debug_info->dir,
386 data: debug_info, fops: &cros_ec_console_log_fops);
387
388 INIT_DELAYED_WORK(&debug_info->log_poll_work,
389 cros_ec_console_log_work);
390 schedule_delayed_work(dwork: &debug_info->log_poll_work, delay: 0);
391
392 return 0;
393}
394
395static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
396{
397 if (debug_info->log_buffer.buf) {
398 cancel_delayed_work_sync(dwork: &debug_info->log_poll_work);
399 mutex_destroy(lock: &debug_info->log_mutex);
400 }
401}
402
403/*
404 * Returns the size of the panicinfo data fetched from the EC
405 */
406static int cros_ec_get_panicinfo(struct cros_ec_device *ec_dev, uint8_t *data,
407 int data_size)
408{
409 int ret;
410 struct cros_ec_command *msg;
411
412 if (!data || data_size <= 0 || data_size > ec_dev->max_response)
413 return -EINVAL;
414
415 msg = kzalloc(size: sizeof(*msg) + data_size, GFP_KERNEL);
416 if (!msg)
417 return -ENOMEM;
418
419 msg->command = EC_CMD_GET_PANIC_INFO;
420 msg->insize = data_size;
421
422 ret = cros_ec_cmd_xfer_status(ec_dev, msg);
423 if (ret < 0)
424 goto free;
425
426 memcpy(data, msg->data, data_size);
427
428free:
429 kfree(objp: msg);
430 return ret;
431}
432
433static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
434{
435 struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
436 int ret;
437 void *data;
438
439 data = devm_kzalloc(dev: debug_info->ec->dev, size: ec_dev->max_response,
440 GFP_KERNEL);
441 if (!data)
442 return -ENOMEM;
443
444 ret = cros_ec_get_panicinfo(ec_dev, data, data_size: ec_dev->max_response);
445 if (ret < 0) {
446 ret = 0;
447 goto free;
448 }
449
450 /* No panic data */
451 if (ret == 0)
452 goto free;
453
454 debug_info->panicinfo_blob.data = data;
455 debug_info->panicinfo_blob.size = ret;
456
457 debugfs_create_blob(name: "panicinfo", S_IFREG | 0444, parent: debug_info->dir,
458 blob: &debug_info->panicinfo_blob);
459
460 return 0;
461
462free:
463 devm_kfree(dev: debug_info->ec->dev, p: data);
464 return ret;
465}
466
467static int cros_ec_debugfs_panic_event(struct notifier_block *nb,
468 unsigned long queued_during_suspend, void *_notify)
469{
470 struct cros_ec_debugfs *debug_info =
471 container_of(nb, struct cros_ec_debugfs, notifier_panic);
472
473 if (debug_info->log_buffer.buf) {
474 /* Force log poll work to run immediately */
475 mod_delayed_work(wq: debug_info->log_poll_work.wq, dwork: &debug_info->log_poll_work, delay: 0);
476 /* Block until log poll work finishes */
477 flush_delayed_work(dwork: &debug_info->log_poll_work);
478 }
479
480 return NOTIFY_DONE;
481}
482
483static int cros_ec_debugfs_probe(struct platform_device *pd)
484{
485 struct cros_ec_dev *ec = dev_get_drvdata(dev: pd->dev.parent);
486 struct cros_ec_platform *ec_platform = dev_get_platdata(dev: ec->dev);
487 const char *name = ec_platform->ec_name;
488 struct cros_ec_debugfs *debug_info;
489 int ret;
490
491 debug_info = devm_kzalloc(dev: ec->dev, size: sizeof(*debug_info), GFP_KERNEL);
492 if (!debug_info)
493 return -ENOMEM;
494
495 debug_info->ec = ec;
496 debug_info->dir = debugfs_create_dir(name, NULL);
497
498 ret = cros_ec_create_panicinfo(debug_info);
499 if (ret)
500 goto remove_debugfs;
501
502 ret = cros_ec_create_console_log(debug_info);
503 if (ret)
504 goto remove_debugfs;
505
506 debugfs_create_file(name: "pdinfo", mode: 0444, parent: debug_info->dir, data: debug_info,
507 fops: &cros_ec_pdinfo_fops);
508
509 if (cros_ec_uptime_is_supported(ec_dev: ec->ec_dev))
510 debugfs_create_file(name: "uptime", mode: 0444, parent: debug_info->dir, data: debug_info,
511 fops: &cros_ec_uptime_fops);
512
513 debugfs_create_x32(name: "last_resume_result", mode: 0444, parent: debug_info->dir,
514 value: &ec->ec_dev->last_resume_result);
515
516 debugfs_create_u16(name: "suspend_timeout_ms", mode: 0664, parent: debug_info->dir,
517 value: &ec->ec_dev->suspend_timeout_ms);
518
519 debug_info->notifier_panic.notifier_call = cros_ec_debugfs_panic_event;
520 ret = blocking_notifier_chain_register(nh: &ec->ec_dev->panic_notifier,
521 nb: &debug_info->notifier_panic);
522 if (ret)
523 goto remove_debugfs;
524
525 ec->debug_info = debug_info;
526
527 dev_set_drvdata(dev: &pd->dev, data: ec);
528
529 return 0;
530
531remove_debugfs:
532 debugfs_remove_recursive(dentry: debug_info->dir);
533 return ret;
534}
535
536static void cros_ec_debugfs_remove(struct platform_device *pd)
537{
538 struct cros_ec_dev *ec = dev_get_drvdata(dev: pd->dev.parent);
539
540 debugfs_remove_recursive(dentry: ec->debug_info->dir);
541 cros_ec_cleanup_console_log(debug_info: ec->debug_info);
542}
543
544static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
545{
546 struct cros_ec_dev *ec = dev_get_drvdata(dev);
547
548 if (ec->debug_info->log_buffer.buf)
549 cancel_delayed_work_sync(dwork: &ec->debug_info->log_poll_work);
550
551 return 0;
552}
553
554static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
555{
556 struct cros_ec_dev *ec = dev_get_drvdata(dev);
557
558 if (ec->debug_info->log_buffer.buf)
559 schedule_delayed_work(dwork: &ec->debug_info->log_poll_work, delay: 0);
560
561 return 0;
562}
563
564static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
565 cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
566
567static struct platform_driver cros_ec_debugfs_driver = {
568 .driver = {
569 .name = DRV_NAME,
570 .pm = &cros_ec_debugfs_pm_ops,
571 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
572 },
573 .probe = cros_ec_debugfs_probe,
574 .remove_new = cros_ec_debugfs_remove,
575};
576
577module_platform_driver(cros_ec_debugfs_driver);
578
579MODULE_LICENSE("GPL");
580MODULE_DESCRIPTION("Debug logs for ChromeOS EC");
581MODULE_ALIAS("platform:" DRV_NAME);
582

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