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e8626459 EC |
1 | /* |
2 | * cros_ec_debugfs - debug logs for Chrome OS EC | |
3 | * | |
4 | * Copyright 2015 Google, Inc. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | ||
20 | #include <linux/circ_buf.h> | |
21 | #include <linux/debugfs.h> | |
22 | #include <linux/delay.h> | |
23 | #include <linux/fs.h> | |
24 | #include <linux/mfd/cros_ec.h> | |
25 | #include <linux/mfd/cros_ec_commands.h> | |
26 | #include <linux/mutex.h> | |
27 | #include <linux/poll.h> | |
28 | #include <linux/sched.h> | |
29 | #include <linux/slab.h> | |
30 | #include <linux/wait.h> | |
31 | ||
e8626459 EC |
32 | #define LOG_SHIFT 14 |
33 | #define LOG_SIZE (1 << LOG_SHIFT) | |
34 | #define LOG_POLL_SEC 10 | |
35 | ||
36 | #define CIRC_ADD(idx, size, value) (((idx) + (value)) & ((size) - 1)) | |
37 | ||
38 | /* struct cros_ec_debugfs - ChromeOS EC debugging information | |
39 | * | |
40 | * @ec: EC device this debugfs information belongs to | |
41 | * @dir: dentry for debugfs files | |
42 | * @log_buffer: circular buffer for console log information | |
43 | * @read_msg: preallocated EC command and buffer to read console log | |
44 | * @log_mutex: mutex to protect circular buffer | |
45 | * @log_wq: waitqueue for log readers | |
46 | * @log_poll_work: recurring task to poll EC for new console log data | |
6e494106 | 47 | * @panicinfo_blob: panicinfo debugfs blob |
e8626459 EC |
48 | */ |
49 | struct cros_ec_debugfs { | |
50 | struct cros_ec_dev *ec; | |
51 | struct dentry *dir; | |
6e494106 | 52 | /* EC log */ |
e8626459 EC |
53 | struct circ_buf log_buffer; |
54 | struct cros_ec_command *read_msg; | |
55 | struct mutex log_mutex; | |
56 | wait_queue_head_t log_wq; | |
57 | struct delayed_work log_poll_work; | |
6e494106 NB |
58 | /* EC panicinfo */ |
59 | struct debugfs_blob_wrapper panicinfo_blob; | |
e8626459 EC |
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_SEC. | |
65 | */ | |
66 | static 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(ec->ec_dev, &snapshot_msg); | |
86 | if (ret < 0) { | |
87 | dev_err(ec->dev, "EC communication failed\n"); | |
88 | goto resched; | |
89 | } | |
90 | if (snapshot_msg.result != EC_RES_SUCCESS) { | |
91 | dev_err(ec->dev, "EC failed to snapshot the console log\n"); | |
92 | goto resched; | |
93 | } | |
94 | ||
95 | /* Loop until we have read everything, or there's an error. */ | |
96 | mutex_lock(&debug_info->log_mutex); | |
97 | buf_space = CIRC_SPACE(cb->head, cb->tail, LOG_SIZE); | |
98 | ||
99 | while (1) { | |
100 | if (!buf_space) { | |
101 | dev_info_once(ec->dev, | |
102 | "Some logs may have been dropped...\n"); | |
103 | break; | |
104 | } | |
105 | ||
106 | memset(read_params, '\0', sizeof(*read_params)); | |
107 | read_params->subcmd = CONSOLE_READ_RECENT; | |
108 | ret = cros_ec_cmd_xfer(ec->ec_dev, debug_info->read_msg); | |
109 | if (ret < 0) { | |
110 | dev_err(ec->dev, "EC communication failed\n"); | |
111 | break; | |
112 | } | |
113 | if (debug_info->read_msg->result != EC_RES_SUCCESS) { | |
114 | dev_err(ec->dev, | |
115 | "EC failed to read the console log\n"); | |
116 | break; | |
117 | } | |
118 | ||
119 | /* If the buffer is empty, we're done here. */ | |
120 | if (ret == 0 || ec_buffer[0] == '\0') | |
121 | break; | |
122 | ||
123 | idx = 0; | |
124 | while (idx < ret && ec_buffer[idx] != '\0' && buf_space > 0) { | |
125 | cb->buf[cb->head] = ec_buffer[idx]; | |
126 | cb->head = CIRC_ADD(cb->head, LOG_SIZE, 1); | |
127 | idx++; | |
128 | buf_space--; | |
129 | } | |
130 | ||
131 | wake_up(&debug_info->log_wq); | |
132 | } | |
133 | ||
134 | mutex_unlock(&debug_info->log_mutex); | |
135 | ||
136 | resched: | |
137 | schedule_delayed_work(&debug_info->log_poll_work, | |
138 | msecs_to_jiffies(LOG_POLL_SEC * 1000)); | |
139 | } | |
140 | ||
141 | static int cros_ec_console_log_open(struct inode *inode, struct file *file) | |
142 | { | |
143 | file->private_data = inode->i_private; | |
144 | ||
145 | return nonseekable_open(inode, file); | |
146 | } | |
147 | ||
148 | static ssize_t cros_ec_console_log_read(struct file *file, char __user *buf, | |
149 | size_t count, loff_t *ppos) | |
150 | { | |
151 | struct cros_ec_debugfs *debug_info = file->private_data; | |
152 | struct circ_buf *cb = &debug_info->log_buffer; | |
153 | ssize_t ret; | |
154 | ||
155 | mutex_lock(&debug_info->log_mutex); | |
156 | ||
157 | while (!CIRC_CNT(cb->head, cb->tail, LOG_SIZE)) { | |
158 | if (file->f_flags & O_NONBLOCK) { | |
159 | ret = -EAGAIN; | |
160 | goto error; | |
161 | } | |
162 | ||
163 | mutex_unlock(&debug_info->log_mutex); | |
164 | ||
165 | ret = wait_event_interruptible(debug_info->log_wq, | |
166 | CIRC_CNT(cb->head, cb->tail, LOG_SIZE)); | |
167 | if (ret < 0) | |
168 | return ret; | |
169 | ||
170 | mutex_lock(&debug_info->log_mutex); | |
171 | } | |
172 | ||
173 | /* Only copy until the end of the circular buffer, and let userspace | |
174 | * retry to get the rest of the data. | |
175 | */ | |
176 | ret = min_t(size_t, CIRC_CNT_TO_END(cb->head, cb->tail, LOG_SIZE), | |
177 | count); | |
178 | ||
179 | if (copy_to_user(buf, cb->buf + cb->tail, ret)) { | |
180 | ret = -EFAULT; | |
181 | goto error; | |
182 | } | |
183 | ||
184 | cb->tail = CIRC_ADD(cb->tail, LOG_SIZE, ret); | |
185 | ||
186 | error: | |
187 | mutex_unlock(&debug_info->log_mutex); | |
188 | return ret; | |
189 | } | |
190 | ||
afc9a42b | 191 | static __poll_t cros_ec_console_log_poll(struct file *file, |
e8626459 EC |
192 | poll_table *wait) |
193 | { | |
194 | struct cros_ec_debugfs *debug_info = file->private_data; | |
afc9a42b | 195 | __poll_t mask = 0; |
e8626459 EC |
196 | |
197 | poll_wait(file, &debug_info->log_wq, wait); | |
198 | ||
199 | mutex_lock(&debug_info->log_mutex); | |
200 | if (CIRC_CNT(debug_info->log_buffer.head, | |
201 | debug_info->log_buffer.tail, | |
202 | LOG_SIZE)) | |
a9a08845 | 203 | mask |= EPOLLIN | EPOLLRDNORM; |
e8626459 EC |
204 | mutex_unlock(&debug_info->log_mutex); |
205 | ||
206 | return mask; | |
207 | } | |
208 | ||
209 | static int cros_ec_console_log_release(struct inode *inode, struct file *file) | |
210 | { | |
211 | return 0; | |
212 | } | |
213 | ||
214 | const struct file_operations cros_ec_console_log_fops = { | |
215 | .owner = THIS_MODULE, | |
216 | .open = cros_ec_console_log_open, | |
217 | .read = cros_ec_console_log_read, | |
218 | .llseek = no_llseek, | |
219 | .poll = cros_ec_console_log_poll, | |
220 | .release = cros_ec_console_log_release, | |
221 | }; | |
222 | ||
223 | static int ec_read_version_supported(struct cros_ec_dev *ec) | |
224 | { | |
225 | struct ec_params_get_cmd_versions_v1 *params; | |
226 | struct ec_response_get_cmd_versions *response; | |
227 | int ret; | |
228 | ||
229 | struct cros_ec_command *msg; | |
230 | ||
73b44f40 | 231 | msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)), |
e8626459 EC |
232 | GFP_KERNEL); |
233 | if (!msg) | |
234 | return 0; | |
235 | ||
236 | msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset; | |
73b44f40 SN |
237 | msg->outsize = sizeof(*params); |
238 | msg->insize = sizeof(*response); | |
e8626459 EC |
239 | |
240 | params = (struct ec_params_get_cmd_versions_v1 *)msg->data; | |
241 | params->cmd = EC_CMD_CONSOLE_READ; | |
242 | response = (struct ec_response_get_cmd_versions *)msg->data; | |
243 | ||
244 | ret = cros_ec_cmd_xfer(ec->ec_dev, msg) >= 0 && | |
245 | msg->result == EC_RES_SUCCESS && | |
246 | (response->version_mask & EC_VER_MASK(1)); | |
247 | ||
248 | kfree(msg); | |
249 | ||
250 | return ret; | |
251 | } | |
252 | ||
253 | static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info) | |
254 | { | |
255 | struct cros_ec_dev *ec = debug_info->ec; | |
256 | char *buf; | |
257 | int read_params_size; | |
258 | int read_response_size; | |
259 | ||
260 | if (!ec_read_version_supported(ec)) { | |
261 | dev_warn(ec->dev, | |
262 | "device does not support reading the console log\n"); | |
263 | return 0; | |
264 | } | |
265 | ||
266 | buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL); | |
267 | if (!buf) | |
268 | return -ENOMEM; | |
269 | ||
270 | read_params_size = sizeof(struct ec_params_console_read_v1); | |
271 | read_response_size = ec->ec_dev->max_response; | |
272 | debug_info->read_msg = devm_kzalloc(ec->dev, | |
273 | sizeof(*debug_info->read_msg) + | |
274 | max(read_params_size, read_response_size), GFP_KERNEL); | |
275 | if (!debug_info->read_msg) | |
276 | return -ENOMEM; | |
277 | ||
278 | debug_info->read_msg->version = 1; | |
279 | debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset; | |
280 | debug_info->read_msg->outsize = read_params_size; | |
281 | debug_info->read_msg->insize = read_response_size; | |
282 | ||
283 | debug_info->log_buffer.buf = buf; | |
284 | debug_info->log_buffer.head = 0; | |
285 | debug_info->log_buffer.tail = 0; | |
286 | ||
287 | mutex_init(&debug_info->log_mutex); | |
288 | init_waitqueue_head(&debug_info->log_wq); | |
289 | ||
290 | if (!debugfs_create_file("console_log", | |
291 | S_IFREG | S_IRUGO, | |
292 | debug_info->dir, | |
293 | debug_info, | |
294 | &cros_ec_console_log_fops)) | |
295 | return -ENOMEM; | |
296 | ||
297 | INIT_DELAYED_WORK(&debug_info->log_poll_work, | |
298 | cros_ec_console_log_work); | |
299 | schedule_delayed_work(&debug_info->log_poll_work, 0); | |
300 | ||
301 | return 0; | |
302 | } | |
303 | ||
304 | static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info) | |
305 | { | |
306 | if (debug_info->log_buffer.buf) { | |
307 | cancel_delayed_work_sync(&debug_info->log_poll_work); | |
308 | mutex_destroy(&debug_info->log_mutex); | |
309 | } | |
310 | } | |
311 | ||
6e494106 NB |
312 | static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info) |
313 | { | |
314 | struct cros_ec_device *ec_dev = debug_info->ec->ec_dev; | |
315 | int ret; | |
316 | struct cros_ec_command *msg; | |
317 | int insize; | |
318 | ||
319 | insize = ec_dev->max_response; | |
320 | ||
321 | msg = devm_kzalloc(debug_info->ec->dev, | |
322 | sizeof(*msg) + insize, GFP_KERNEL); | |
323 | if (!msg) | |
324 | return -ENOMEM; | |
325 | ||
326 | msg->command = EC_CMD_GET_PANIC_INFO; | |
327 | msg->insize = insize; | |
328 | ||
329 | ret = cros_ec_cmd_xfer(ec_dev, msg); | |
330 | if (ret < 0) { | |
331 | dev_warn(debug_info->ec->dev, "Cannot read panicinfo.\n"); | |
332 | ret = 0; | |
333 | goto free; | |
334 | } | |
335 | ||
336 | /* No panic data */ | |
337 | if (ret == 0) | |
338 | goto free; | |
339 | ||
340 | debug_info->panicinfo_blob.data = msg->data; | |
341 | debug_info->panicinfo_blob.size = ret; | |
342 | ||
343 | if (!debugfs_create_blob("panicinfo", | |
344 | S_IFREG | S_IRUGO, | |
345 | debug_info->dir, | |
346 | &debug_info->panicinfo_blob)) { | |
347 | ret = -ENOMEM; | |
348 | goto free; | |
349 | } | |
350 | ||
351 | return 0; | |
352 | ||
353 | free: | |
354 | devm_kfree(debug_info->ec->dev, msg); | |
355 | return ret; | |
356 | } | |
357 | ||
e8626459 EC |
358 | int cros_ec_debugfs_init(struct cros_ec_dev *ec) |
359 | { | |
360 | struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev); | |
361 | const char *name = ec_platform->ec_name; | |
362 | struct cros_ec_debugfs *debug_info; | |
363 | int ret; | |
364 | ||
365 | debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL); | |
366 | if (!debug_info) | |
367 | return -ENOMEM; | |
368 | ||
369 | debug_info->ec = ec; | |
370 | debug_info->dir = debugfs_create_dir(name, NULL); | |
371 | if (!debug_info->dir) | |
372 | return -ENOMEM; | |
373 | ||
6e494106 NB |
374 | ret = cros_ec_create_panicinfo(debug_info); |
375 | if (ret) | |
376 | goto remove_debugfs; | |
377 | ||
e8626459 EC |
378 | ret = cros_ec_create_console_log(debug_info); |
379 | if (ret) | |
380 | goto remove_debugfs; | |
381 | ||
382 | ec->debug_info = debug_info; | |
383 | ||
384 | return 0; | |
385 | ||
386 | remove_debugfs: | |
387 | debugfs_remove_recursive(debug_info->dir); | |
388 | return ret; | |
389 | } | |
ea01a31b | 390 | EXPORT_SYMBOL(cros_ec_debugfs_init); |
e8626459 EC |
391 | |
392 | void cros_ec_debugfs_remove(struct cros_ec_dev *ec) | |
393 | { | |
394 | if (!ec->debug_info) | |
395 | return; | |
396 | ||
397 | debugfs_remove_recursive(ec->debug_info->dir); | |
398 | cros_ec_cleanup_console_log(ec->debug_info); | |
399 | } | |
ea01a31b | 400 | EXPORT_SYMBOL(cros_ec_debugfs_remove); |