Merge tag 'platform-drivers-x86-v4.20-1' of git://git.infradead.org/linux-platform...
[sfrench/cifs-2.6.git] / drivers / platform / chrome / cros_ec_debugfs.c
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
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
47  * @panicinfo_blob: panicinfo debugfs blob
48  */
49 struct 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         wait_queue_head_t log_wq;
57         struct delayed_work log_poll_work;
58         /* EC panicinfo */
59         struct debugfs_blob_wrapper panicinfo_blob;
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
191 static __poll_t cros_ec_console_log_poll(struct file *file,
192                                              poll_table *wait)
193 {
194         struct cros_ec_debugfs *debug_info = file->private_data;
195         __poll_t mask = 0;
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))
203                 mask |= EPOLLIN | EPOLLRDNORM;
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 static ssize_t cros_ec_pdinfo_read(struct file *file,
215                                    char __user *user_buf,
216                                    size_t count,
217                                    loff_t *ppos)
218 {
219         char read_buf[EC_USB_PD_MAX_PORTS * 40], *p = read_buf;
220         struct cros_ec_debugfs *debug_info = file->private_data;
221         struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
222         struct {
223                 struct cros_ec_command msg;
224                 union {
225                         struct ec_response_usb_pd_control_v1 resp;
226                         struct ec_params_usb_pd_control params;
227                 };
228         } __packed ec_buf;
229         struct cros_ec_command *msg;
230         struct ec_response_usb_pd_control_v1 *resp;
231         struct ec_params_usb_pd_control *params;
232         int i;
233
234         msg = &ec_buf.msg;
235         params = (struct ec_params_usb_pd_control *)msg->data;
236         resp = (struct ec_response_usb_pd_control_v1 *)msg->data;
237
238         msg->command = EC_CMD_USB_PD_CONTROL;
239         msg->version = 1;
240         msg->insize = sizeof(*resp);
241         msg->outsize = sizeof(*params);
242
243         /*
244          * Read status from all PD ports until failure, typically caused
245          * by attempting to read status on a port that doesn't exist.
246          */
247         for (i = 0; i < EC_USB_PD_MAX_PORTS; ++i) {
248                 params->port = i;
249                 params->role = 0;
250                 params->mux = 0;
251                 params->swap = 0;
252
253                 if (cros_ec_cmd_xfer_status(ec_dev, msg) < 0)
254                         break;
255
256                 p += scnprintf(p, sizeof(read_buf) + read_buf - p,
257                                "p%d: %s en:%.2x role:%.2x pol:%.2x\n", i,
258                                resp->state, resp->enabled, resp->role,
259                                resp->polarity);
260         }
261
262         return simple_read_from_buffer(user_buf, count, ppos,
263                                        read_buf, p - read_buf);
264 }
265
266 const struct file_operations cros_ec_console_log_fops = {
267         .owner = THIS_MODULE,
268         .open = cros_ec_console_log_open,
269         .read = cros_ec_console_log_read,
270         .llseek = no_llseek,
271         .poll = cros_ec_console_log_poll,
272         .release = cros_ec_console_log_release,
273 };
274
275 const struct file_operations cros_ec_pdinfo_fops = {
276         .owner = THIS_MODULE,
277         .open = simple_open,
278         .read = cros_ec_pdinfo_read,
279         .llseek = default_llseek,
280 };
281
282 static int ec_read_version_supported(struct cros_ec_dev *ec)
283 {
284         struct ec_params_get_cmd_versions_v1 *params;
285         struct ec_response_get_cmd_versions *response;
286         int ret;
287
288         struct cros_ec_command *msg;
289
290         msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
291                 GFP_KERNEL);
292         if (!msg)
293                 return 0;
294
295         msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
296         msg->outsize = sizeof(*params);
297         msg->insize = sizeof(*response);
298
299         params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
300         params->cmd = EC_CMD_CONSOLE_READ;
301         response = (struct ec_response_get_cmd_versions *)msg->data;
302
303         ret = cros_ec_cmd_xfer(ec->ec_dev, msg) >= 0 &&
304                 msg->result == EC_RES_SUCCESS &&
305                 (response->version_mask & EC_VER_MASK(1));
306
307         kfree(msg);
308
309         return ret;
310 }
311
312 static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
313 {
314         struct cros_ec_dev *ec = debug_info->ec;
315         char *buf;
316         int read_params_size;
317         int read_response_size;
318
319         if (!ec_read_version_supported(ec)) {
320                 dev_warn(ec->dev,
321                         "device does not support reading the console log\n");
322                 return 0;
323         }
324
325         buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
326         if (!buf)
327                 return -ENOMEM;
328
329         read_params_size = sizeof(struct ec_params_console_read_v1);
330         read_response_size = ec->ec_dev->max_response;
331         debug_info->read_msg = devm_kzalloc(ec->dev,
332                 sizeof(*debug_info->read_msg) +
333                         max(read_params_size, read_response_size), GFP_KERNEL);
334         if (!debug_info->read_msg)
335                 return -ENOMEM;
336
337         debug_info->read_msg->version = 1;
338         debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
339         debug_info->read_msg->outsize = read_params_size;
340         debug_info->read_msg->insize = read_response_size;
341
342         debug_info->log_buffer.buf = buf;
343         debug_info->log_buffer.head = 0;
344         debug_info->log_buffer.tail = 0;
345
346         mutex_init(&debug_info->log_mutex);
347         init_waitqueue_head(&debug_info->log_wq);
348
349         if (!debugfs_create_file("console_log",
350                                  S_IFREG | 0444,
351                                  debug_info->dir,
352                                  debug_info,
353                                  &cros_ec_console_log_fops))
354                 return -ENOMEM;
355
356         INIT_DELAYED_WORK(&debug_info->log_poll_work,
357                           cros_ec_console_log_work);
358         schedule_delayed_work(&debug_info->log_poll_work, 0);
359
360         return 0;
361 }
362
363 static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
364 {
365         if (debug_info->log_buffer.buf) {
366                 cancel_delayed_work_sync(&debug_info->log_poll_work);
367                 mutex_destroy(&debug_info->log_mutex);
368         }
369 }
370
371 static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
372 {
373         struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
374         int ret;
375         struct cros_ec_command *msg;
376         int insize;
377
378         insize = ec_dev->max_response;
379
380         msg = devm_kzalloc(debug_info->ec->dev,
381                         sizeof(*msg) + insize, GFP_KERNEL);
382         if (!msg)
383                 return -ENOMEM;
384
385         msg->command = EC_CMD_GET_PANIC_INFO;
386         msg->insize = insize;
387
388         ret = cros_ec_cmd_xfer(ec_dev, msg);
389         if (ret < 0) {
390                 dev_warn(debug_info->ec->dev, "Cannot read panicinfo.\n");
391                 ret = 0;
392                 goto free;
393         }
394
395         /* No panic data */
396         if (ret == 0)
397                 goto free;
398
399         debug_info->panicinfo_blob.data = msg->data;
400         debug_info->panicinfo_blob.size = ret;
401
402         if (!debugfs_create_blob("panicinfo",
403                                  S_IFREG | 0444,
404                                  debug_info->dir,
405                                  &debug_info->panicinfo_blob)) {
406                 ret = -ENOMEM;
407                 goto free;
408         }
409
410         return 0;
411
412 free:
413         devm_kfree(debug_info->ec->dev, msg);
414         return ret;
415 }
416
417 static int cros_ec_create_pdinfo(struct cros_ec_debugfs *debug_info)
418 {
419         if (!debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
420                                  &cros_ec_pdinfo_fops))
421                 return -ENOMEM;
422
423         return 0;
424 }
425
426 int cros_ec_debugfs_init(struct cros_ec_dev *ec)
427 {
428         struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
429         const char *name = ec_platform->ec_name;
430         struct cros_ec_debugfs *debug_info;
431         int ret;
432
433         debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
434         if (!debug_info)
435                 return -ENOMEM;
436
437         debug_info->ec = ec;
438         debug_info->dir = debugfs_create_dir(name, NULL);
439         if (!debug_info->dir)
440                 return -ENOMEM;
441
442         ret = cros_ec_create_panicinfo(debug_info);
443         if (ret)
444                 goto remove_debugfs;
445
446         ret = cros_ec_create_console_log(debug_info);
447         if (ret)
448                 goto remove_debugfs;
449
450         ret = cros_ec_create_pdinfo(debug_info);
451         if (ret)
452                 goto remove_debugfs;
453
454         ec->debug_info = debug_info;
455
456         return 0;
457
458 remove_debugfs:
459         debugfs_remove_recursive(debug_info->dir);
460         return ret;
461 }
462 EXPORT_SYMBOL(cros_ec_debugfs_init);
463
464 void cros_ec_debugfs_remove(struct cros_ec_dev *ec)
465 {
466         if (!ec->debug_info)
467                 return;
468
469         debugfs_remove_recursive(ec->debug_info->dir);
470         cros_ec_cleanup_console_log(ec->debug_info);
471 }
472 EXPORT_SYMBOL(cros_ec_debugfs_remove);
473
474 void cros_ec_debugfs_suspend(struct cros_ec_dev *ec)
475 {
476         /*
477          * cros_ec_debugfs_init() failures are non-fatal; it's also possible
478          * that we initted things but decided that console log wasn't supported.
479          * We'll use the same set of checks that cros_ec_debugfs_remove() +
480          * cros_ec_cleanup_console_log() end up using to handle those cases.
481          */
482         if (ec->debug_info && ec->debug_info->log_buffer.buf)
483                 cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
484 }
485 EXPORT_SYMBOL(cros_ec_debugfs_suspend);
486
487 void cros_ec_debugfs_resume(struct cros_ec_dev *ec)
488 {
489         if (ec->debug_info && ec->debug_info->log_buffer.buf)
490                 schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
491 }
492 EXPORT_SYMBOL(cros_ec_debugfs_resume);