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 */
42 struct cros_ec_debugfs {
43 struct cros_ec_dev *ec;
44 struct dentry *dir;
45 /* EC log */
46 struct circ_buf log_buffer;
47 struct cros_ec_command *read_msg;
48 struct mutex log_mutex;
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 */
cros_ec_console_log_work(struct work_struct * __work)58 static 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(&cros_ec_debugfs_log_wq);
112 }
113
114 mutex_unlock(&debug_info->log_mutex);
115
116 resched:
117 schedule_delayed_work(&debug_info->log_poll_work,
118 msecs_to_jiffies(LOG_POLL_SEC * 1000));
119 }
120
cros_ec_console_log_open(struct inode * inode,struct file * file)121 static 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
cros_ec_console_log_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)128 static 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(cros_ec_debugfs_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
166 error:
167 mutex_unlock(&debug_info->log_mutex);
168 return ret;
169 }
170
cros_ec_console_log_poll(struct file * file,poll_table * wait)171 static __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, &cros_ec_debugfs_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
cros_ec_console_log_release(struct inode * inode,struct file * file)189 static int cros_ec_console_log_release(struct inode *inode, struct file *file)
190 {
191 return 0;
192 }
193
cros_ec_pdinfo_read(struct file * file,char __user * user_buf,size_t count,loff_t * ppos)194 static 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
cros_ec_uptime_is_supported(struct cros_ec_device * ec_dev)246 static bool cros_ec_uptime_is_supported(struct cros_ec_device *ec_dev)
247 {
248 struct {
249 struct cros_ec_command cmd;
250 struct ec_response_uptime_info resp;
251 } __packed msg = {};
252 int ret;
253
254 msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
255 msg.cmd.insize = sizeof(msg.resp);
256
257 ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
258 if (ret == -EPROTO && msg.cmd.result == EC_RES_INVALID_COMMAND)
259 return false;
260
261 /* Other errors maybe a transient error, do not rule about support. */
262 return true;
263 }
264
cros_ec_uptime_read(struct file * file,char __user * user_buf,size_t count,loff_t * ppos)265 static ssize_t cros_ec_uptime_read(struct file *file, char __user *user_buf,
266 size_t count, loff_t *ppos)
267 {
268 struct cros_ec_debugfs *debug_info = file->private_data;
269 struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
270 struct {
271 struct cros_ec_command cmd;
272 struct ec_response_uptime_info resp;
273 } __packed msg = {};
274 struct ec_response_uptime_info *resp;
275 char read_buf[32];
276 int ret;
277
278 resp = (struct ec_response_uptime_info *)&msg.resp;
279
280 msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
281 msg.cmd.insize = sizeof(*resp);
282
283 ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
284 if (ret < 0)
285 return ret;
286
287 ret = scnprintf(read_buf, sizeof(read_buf), "%u\n",
288 resp->time_since_ec_boot_ms);
289
290 return simple_read_from_buffer(user_buf, count, ppos, read_buf, ret);
291 }
292
293 static const struct file_operations cros_ec_console_log_fops = {
294 .owner = THIS_MODULE,
295 .open = cros_ec_console_log_open,
296 .read = cros_ec_console_log_read,
297 .llseek = no_llseek,
298 .poll = cros_ec_console_log_poll,
299 .release = cros_ec_console_log_release,
300 };
301
302 static const struct file_operations cros_ec_pdinfo_fops = {
303 .owner = THIS_MODULE,
304 .open = simple_open,
305 .read = cros_ec_pdinfo_read,
306 .llseek = default_llseek,
307 };
308
309 static const struct file_operations cros_ec_uptime_fops = {
310 .owner = THIS_MODULE,
311 .open = simple_open,
312 .read = cros_ec_uptime_read,
313 .llseek = default_llseek,
314 };
315
ec_read_version_supported(struct cros_ec_dev * ec)316 static int ec_read_version_supported(struct cros_ec_dev *ec)
317 {
318 struct ec_params_get_cmd_versions_v1 *params;
319 struct ec_response_get_cmd_versions *response;
320 int ret;
321
322 struct cros_ec_command *msg;
323
324 msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
325 GFP_KERNEL);
326 if (!msg)
327 return 0;
328
329 msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
330 msg->outsize = sizeof(*params);
331 msg->insize = sizeof(*response);
332
333 params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
334 params->cmd = EC_CMD_CONSOLE_READ;
335 response = (struct ec_response_get_cmd_versions *)msg->data;
336
337 ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg) >= 0 &&
338 response->version_mask & EC_VER_MASK(1);
339
340 kfree(msg);
341
342 return ret;
343 }
344
cros_ec_create_console_log(struct cros_ec_debugfs * debug_info)345 static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
346 {
347 struct cros_ec_dev *ec = debug_info->ec;
348 char *buf;
349 int read_params_size;
350 int read_response_size;
351
352 /*
353 * If the console log feature is not supported return silently and
354 * don't create the console_log entry.
355 */
356 if (!ec_read_version_supported(ec))
357 return 0;
358
359 buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
360 if (!buf)
361 return -ENOMEM;
362
363 read_params_size = sizeof(struct ec_params_console_read_v1);
364 read_response_size = ec->ec_dev->max_response;
365 debug_info->read_msg = devm_kzalloc(ec->dev,
366 sizeof(*debug_info->read_msg) +
367 max(read_params_size, read_response_size), GFP_KERNEL);
368 if (!debug_info->read_msg)
369 return -ENOMEM;
370
371 debug_info->read_msg->version = 1;
372 debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
373 debug_info->read_msg->outsize = read_params_size;
374 debug_info->read_msg->insize = read_response_size;
375
376 debug_info->log_buffer.buf = buf;
377 debug_info->log_buffer.head = 0;
378 debug_info->log_buffer.tail = 0;
379
380 mutex_init(&debug_info->log_mutex);
381
382 debugfs_create_file("console_log", S_IFREG | 0444, debug_info->dir,
383 debug_info, &cros_ec_console_log_fops);
384
385 INIT_DELAYED_WORK(&debug_info->log_poll_work,
386 cros_ec_console_log_work);
387 schedule_delayed_work(&debug_info->log_poll_work, 0);
388
389 return 0;
390 }
391
cros_ec_cleanup_console_log(struct cros_ec_debugfs * debug_info)392 static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
393 {
394 if (debug_info->log_buffer.buf) {
395 cancel_delayed_work_sync(&debug_info->log_poll_work);
396 mutex_destroy(&debug_info->log_mutex);
397 }
398 }
399
cros_ec_create_panicinfo(struct cros_ec_debugfs * debug_info)400 static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
401 {
402 struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
403 int ret;
404 struct cros_ec_command *msg;
405 int insize;
406
407 insize = ec_dev->max_response;
408
409 msg = devm_kzalloc(debug_info->ec->dev,
410 sizeof(*msg) + insize, GFP_KERNEL);
411 if (!msg)
412 return -ENOMEM;
413
414 msg->command = EC_CMD_GET_PANIC_INFO;
415 msg->insize = insize;
416
417 ret = cros_ec_cmd_xfer_status(ec_dev, msg);
418 if (ret < 0) {
419 ret = 0;
420 goto free;
421 }
422
423 /* No panic data */
424 if (ret == 0)
425 goto free;
426
427 debug_info->panicinfo_blob.data = msg->data;
428 debug_info->panicinfo_blob.size = ret;
429
430 debugfs_create_blob("panicinfo", S_IFREG | 0444, debug_info->dir,
431 &debug_info->panicinfo_blob);
432
433 return 0;
434
435 free:
436 devm_kfree(debug_info->ec->dev, msg);
437 return ret;
438 }
439
cros_ec_debugfs_probe(struct platform_device * pd)440 static int cros_ec_debugfs_probe(struct platform_device *pd)
441 {
442 struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
443 struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
444 const char *name = ec_platform->ec_name;
445 struct cros_ec_debugfs *debug_info;
446 int ret;
447
448 debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
449 if (!debug_info)
450 return -ENOMEM;
451
452 debug_info->ec = ec;
453 debug_info->dir = debugfs_create_dir(name, NULL);
454
455 ret = cros_ec_create_panicinfo(debug_info);
456 if (ret)
457 goto remove_debugfs;
458
459 ret = cros_ec_create_console_log(debug_info);
460 if (ret)
461 goto remove_debugfs;
462
463 debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
464 &cros_ec_pdinfo_fops);
465
466 if (cros_ec_uptime_is_supported(ec->ec_dev))
467 debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
468 &cros_ec_uptime_fops);
469
470 debugfs_create_x32("last_resume_result", 0444, debug_info->dir,
471 &ec->ec_dev->last_resume_result);
472
473 ec->debug_info = debug_info;
474
475 dev_set_drvdata(&pd->dev, ec);
476
477 return 0;
478
479 remove_debugfs:
480 debugfs_remove_recursive(debug_info->dir);
481 return ret;
482 }
483
cros_ec_debugfs_remove(struct platform_device * pd)484 static int cros_ec_debugfs_remove(struct platform_device *pd)
485 {
486 struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
487
488 debugfs_remove_recursive(ec->debug_info->dir);
489 cros_ec_cleanup_console_log(ec->debug_info);
490
491 return 0;
492 }
493
cros_ec_debugfs_suspend(struct device * dev)494 static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
495 {
496 struct cros_ec_dev *ec = dev_get_drvdata(dev);
497
498 if (ec->debug_info->log_buffer.buf)
499 cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
500
501 return 0;
502 }
503
cros_ec_debugfs_resume(struct device * dev)504 static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
505 {
506 struct cros_ec_dev *ec = dev_get_drvdata(dev);
507
508 if (ec->debug_info->log_buffer.buf)
509 schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
510
511 return 0;
512 }
513
514 static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
515 cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
516
517 static struct platform_driver cros_ec_debugfs_driver = {
518 .driver = {
519 .name = DRV_NAME,
520 .pm = &cros_ec_debugfs_pm_ops,
521 },
522 .probe = cros_ec_debugfs_probe,
523 .remove = cros_ec_debugfs_remove,
524 };
525
526 module_platform_driver(cros_ec_debugfs_driver);
527
528 MODULE_LICENSE("GPL");
529 MODULE_DESCRIPTION("Debug logs for ChromeOS EC");
530 MODULE_ALIAS("platform:" DRV_NAME);
531