drivers/platform/chrome/cros_ec_debugfs.c

   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
  29 /* waitqueue for log readers */
  30 static DECLARE_WAIT_QUEUE_HEAD(cros_ec_debugfs_log_wq);
  31
  32 /**
  33  * struct cros_ec_debugfs - EC debugging information.
  34  *
  35  * @ec: EC device this debugfs information belongs to
  36  * @dir: dentry for debugfs files
  37  * @log_buffer: circular buffer for console log information
  38  * @read_msg: preallocated EC command and buffer to read console log
  39  * @log_mutex: mutex to protect circular buffer
  40  * @log_poll_work: recurring task to poll EC for new console log data
  41  * @panicinfo_blob: panicinfo debugfs blob
  42  * @notifier_panic: notifier_block to let kernel to flush buffered log
  43  *                  when EC panic
  44  */
  45 struct cros_ec_debugfs {
  46         struct cros_ec_dev *ec;
  47         struct dentry *dir;
  48         /* EC log */
  49         struct circ_buf log_buffer;
  50         struct cros_ec_command *read_msg;
  51         struct mutex log_mutex;
  52         struct delayed_work log_poll_work;
  53         /* EC panicinfo */
  54         struct debugfs_blob_wrapper panicinfo_blob;
  55         struct notifier_block notifier_panic;
  56 };
  57
  58 /*
  59  * We need to make sure that the EC log buffer on the UART is large enough,
  60  * so that it is unlikely enough to overlow within LOG_POLL_SEC.
  61  */
  62 static void cros_ec_console_log_work(struct work_struct *__work)
  63 {
  64         struct cros_ec_debugfs *debug_info =
  65                 container_of(to_delayed_work(__work),
  66                              struct cros_ec_debugfs,
  67                              log_poll_work);
  68         struct cros_ec_dev *ec = debug_info->ec;
  69         struct circ_buf *cb = &debug_info->log_buffer;
  70         struct cros_ec_command snapshot_msg = {
  71                 .command = EC_CMD_CONSOLE_SNAPSHOT + ec->cmd_offset,
  72         };
  73
  74         struct ec_params_console_read_v1 *read_params =
  75                 (struct ec_params_console_read_v1 *)debug_info->read_msg->data;
  76         uint8_t *ec_buffer = (uint8_t *)debug_info->read_msg->data;
  77         int idx;
  78         int buf_space;
  79         int ret;
  80
  81         ret = cros_ec_cmd_xfer_status(ec->ec_dev, &snapshot_msg);
  82         if (ret < 0)
  83                 goto resched;
  84
  85         /* Loop until we have read everything, or there's an error. */
  86         mutex_lock(&debug_info->log_mutex);
  87         buf_space = CIRC_SPACE(cb->head, cb->tail, LOG_SIZE);
  88
  89         while (1) {
  90                 if (!buf_space) {
  91                         dev_info_once(ec->dev,
  92                                       "Some logs may have been dropped...\n");
  93                         break;
  94                 }
  95
  96                 memset(read_params, '\0', sizeof(*read_params));
  97                 read_params->subcmd = CONSOLE_READ_RECENT;
  98                 ret = cros_ec_cmd_xfer_status(ec->ec_dev,
  99                                               debug_info->read_msg);
 100                 if (ret < 0)
 101                         break;
 102
 103                 /* If the buffer is empty, we're done here. */
 104                 if (ret == 0 || ec_buffer[0] == '\0')
 105                         break;
 106
 107                 idx = 0;
 108                 while (idx < ret && ec_buffer[idx] != '\0' && buf_space > 0) {
 109                         cb->buf[cb->head] = ec_buffer[idx];
 110                         cb->head = CIRC_ADD(cb->head, LOG_SIZE, 1);
 111                         idx++;
 112                         buf_space--;
 113                 }
 114
 115                 wake_up(&cros_ec_debugfs_log_wq);
 116         }
 117
 118         mutex_unlock(&debug_info->log_mutex);
 119
 120 resched:
 121         schedule_delayed_work(&debug_info->log_poll_work,
 122                               msecs_to_jiffies(LOG_POLL_SEC * 1000));
 123 }
 124
 125 static int cros_ec_console_log_open(struct inode *inode, struct file *file)
 126 {
 127         file->private_data = inode->i_private;
 128
 129         return stream_open(inode, file);
 130 }
 131
 132 static ssize_t cros_ec_console_log_read(struct file *file, char __user *buf,
 133                                         size_t count, loff_t *ppos)
 134 {
 135         struct cros_ec_debugfs *debug_info = file->private_data;
 136         struct circ_buf *cb = &debug_info->log_buffer;
 137         ssize_t ret;
 138
 139         mutex_lock(&debug_info->log_mutex);
 140
 141         while (!CIRC_CNT(cb->head, cb->tail, LOG_SIZE)) {
 142                 if (file->f_flags & O_NONBLOCK) {
 143                         ret = -EAGAIN;
 144                         goto error;
 145                 }
 146
 147                 mutex_unlock(&debug_info->log_mutex);
 148
 149                 ret = wait_event_interruptible(cros_ec_debugfs_log_wq,
 150                                         CIRC_CNT(cb->head, cb->tail, LOG_SIZE));
 151                 if (ret < 0)
 152                         return ret;
 153
 154                 mutex_lock(&debug_info->log_mutex);
 155         }
 156
 157         /* Only copy until the end of the circular buffer, and let userspace
 158          * retry to get the rest of the data.
 159          */
 160         ret = min_t(size_t, CIRC_CNT_TO_END(cb->head, cb->tail, LOG_SIZE),
 161                     count);
 162
 163         if (copy_to_user(buf, cb->buf + cb->tail, ret)) {
 164                 ret = -EFAULT;
 165                 goto error;
 166         }
 167
 168         cb->tail = CIRC_ADD(cb->tail, LOG_SIZE, ret);
 169
 170 error:
 171         mutex_unlock(&debug_info->log_mutex);
 172         return ret;
 173 }
 174
 175 static __poll_t cros_ec_console_log_poll(struct file *file,
 176                                              poll_table *wait)
 177 {
 178         struct cros_ec_debugfs *debug_info = file->private_data;
 179         __poll_t mask = 0;
 180
 181         poll_wait(file, &cros_ec_debugfs_log_wq, wait);
 182
 183         mutex_lock(&debug_info->log_mutex);
 184         if (CIRC_CNT(debug_info->log_buffer.head,
 185                      debug_info->log_buffer.tail,
 186                      LOG_SIZE))
 187                 mask |= EPOLLIN | EPOLLRDNORM;
 188         mutex_unlock(&debug_info->log_mutex);
 189
 190         return mask;
 191 }
 192
 193 static int cros_ec_console_log_release(struct inode *inode, struct file *file)
 194 {
 195         return 0;
 196 }
 197
 198 static ssize_t cros_ec_pdinfo_read(struct file *file,
 199                                    char __user *user_buf,
 200                                    size_t count,
 201                                    loff_t *ppos)
 202 {
 203         char read_buf[EC_USB_PD_MAX_PORTS * 40], *p = read_buf;
 204         struct cros_ec_debugfs *debug_info = file->private_data;
 205         struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
 206         struct {
 207                 struct cros_ec_command msg;
 208                 union {
 209                         struct ec_response_usb_pd_control_v1 resp;
 210                         struct ec_params_usb_pd_control params;
 211                 };
 212         } __packed ec_buf;
 213         struct cros_ec_command *msg;
 214         struct ec_response_usb_pd_control_v1 *resp;
 215         struct ec_params_usb_pd_control *params;
 216         int i;
 217
 218         msg = &ec_buf.msg;
 219         params = (struct ec_params_usb_pd_control *)msg->data;
 220         resp = (struct ec_response_usb_pd_control_v1 *)msg->data;
 221
 222         msg->command = EC_CMD_USB_PD_CONTROL;
 223         msg->version = 1;
 224         msg->insize = sizeof(*resp);
 225         msg->outsize = sizeof(*params);
 226
 227         /*
 228          * Read status from all PD ports until failure, typically caused
 229          * by attempting to read status on a port that doesn't exist.
 230          */
 231         for (i = 0; i < EC_USB_PD_MAX_PORTS; ++i) {
 232                 params->port = i;
 233                 params->role = 0;
 234                 params->mux = 0;
 235                 params->swap = 0;
 236
 237                 if (cros_ec_cmd_xfer_status(ec_dev, msg) < 0)
 238                         break;
 239
 240                 p += scnprintf(p, sizeof(read_buf) + read_buf - p,
 241                                "p%d: %s en:%.2x role:%.2x pol:%.2x\n", i,
 242                                resp->state, resp->enabled, resp->role,
 243                                resp->polarity);
 244         }
 245
 246         return simple_read_from_buffer(user_buf, count, ppos,
 247                                        read_buf, p - read_buf);
 248 }
 249
 250 static bool cros_ec_uptime_is_supported(struct cros_ec_device *ec_dev)
 251 {
 252         struct {
 253                 struct cros_ec_command cmd;
 254                 struct ec_response_uptime_info resp;
 255         } __packed msg = {};
 256         int ret;
 257
 258         msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
 259         msg.cmd.insize = sizeof(msg.resp);
 260
 261         ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
 262         if (ret == -EPROTO && msg.cmd.result == EC_RES_INVALID_COMMAND)
 263                 return false;
 264
 265         /* Other errors maybe a transient error, do not rule about support. */
 266         return true;
 267 }
 268
 269 static ssize_t cros_ec_uptime_read(struct file *file, char __user *user_buf,
 270                                    size_t count, loff_t *ppos)
 271 {
 272         struct cros_ec_debugfs *debug_info = file->private_data;
 273         struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
 274         struct {
 275                 struct cros_ec_command cmd;
 276                 struct ec_response_uptime_info resp;
 277         } __packed msg = {};
 278         struct ec_response_uptime_info *resp;
 279         char read_buf[32];
 280         int ret;
 281
 282         resp = (struct ec_response_uptime_info *)&msg.resp;
 283
 284         msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
 285         msg.cmd.insize = sizeof(*resp);
 286
 287         ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
 288         if (ret < 0)
 289                 return ret;
 290
 291         ret = scnprintf(read_buf, sizeof(read_buf), "%u\n",
 292                         resp->time_since_ec_boot_ms);
 293
 294         return simple_read_from_buffer(user_buf, count, ppos, read_buf, ret);
 295 }
 296
 297 static const struct file_operations cros_ec_console_log_fops = {
 298         .owner = THIS_MODULE,
 299         .open = cros_ec_console_log_open,
 300         .read = cros_ec_console_log_read,
 301         .llseek = no_llseek,
 302         .poll = cros_ec_console_log_poll,
 303         .release = cros_ec_console_log_release,
 304 };
 305
 306 static const struct file_operations cros_ec_pdinfo_fops = {
 307         .owner = THIS_MODULE,
 308         .open = simple_open,
 309         .read = cros_ec_pdinfo_read,
 310         .llseek = default_llseek,
 311 };
 312
 313 static const struct file_operations cros_ec_uptime_fops = {
 314         .owner = THIS_MODULE,
 315         .open = simple_open,
 316         .read = cros_ec_uptime_read,
 317         .llseek = default_llseek,
 318 };
 319
 320 static int ec_read_version_supported(struct cros_ec_dev *ec)
 321 {
 322         struct ec_params_get_cmd_versions_v1 *params;
 323         struct ec_response_get_cmd_versions *response;
 324         int ret;
 325
 326         struct cros_ec_command *msg;
 327
 328         msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
 329                 GFP_KERNEL);
 330         if (!msg)
 331                 return 0;
 332
 333         msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
 334         msg->outsize = sizeof(*params);
 335         msg->insize = sizeof(*response);
 336
 337         params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
 338         params->cmd = EC_CMD_CONSOLE_READ;
 339         response = (struct ec_response_get_cmd_versions *)msg->data;
 340
 341         ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg) >= 0 &&
 342               response->version_mask & EC_VER_MASK(1);
 343
 344         kfree(msg);
 345
 346         return ret;
 347 }
 348
 349 static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
 350 {
 351         struct cros_ec_dev *ec = debug_info->ec;
 352         char *buf;
 353         int read_params_size;
 354         int read_response_size;
 355
 356         /*
 357          * If the console log feature is not supported return silently and
 358          * don't create the console_log entry.
 359          */
 360         if (!ec_read_version_supported(ec))
 361                 return 0;
 362
 363         buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
 364         if (!buf)
 365                 return -ENOMEM;
 366
 367         read_params_size = sizeof(struct ec_params_console_read_v1);
 368         read_response_size = ec->ec_dev->max_response;
 369         debug_info->read_msg = devm_kzalloc(ec->dev,
 370                 sizeof(*debug_info->read_msg) +
 371                         max(read_params_size, read_response_size), GFP_KERNEL);
 372         if (!debug_info->read_msg)
 373                 return -ENOMEM;
 374
 375         debug_info->read_msg->version = 1;
 376         debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
 377         debug_info->read_msg->outsize = read_params_size;
 378         debug_info->read_msg->insize = read_response_size;
 379
 380         debug_info->log_buffer.buf = buf;
 381         debug_info->log_buffer.head = 0;
 382         debug_info->log_buffer.tail = 0;
 383
 384         mutex_init(&debug_info->log_mutex);
 385
 386         debugfs_create_file("console_log", S_IFREG | 0444, debug_info->dir,
 387                             debug_info, &cros_ec_console_log_fops);
 388
 389         INIT_DELAYED_WORK(&debug_info->log_poll_work,
 390                           cros_ec_console_log_work);
 391         schedule_delayed_work(&debug_info->log_poll_work, 0);
 392
 393         return 0;
 394 }
 395
 396 static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
 397 {
 398         if (debug_info->log_buffer.buf) {
 399                 cancel_delayed_work_sync(&debug_info->log_poll_work);
 400                 mutex_destroy(&debug_info->log_mutex);
 401         }
 402 }
 403
 404 /*
 405  * Returns the size of the panicinfo data fetched from the EC
 406  */
 407 static int cros_ec_get_panicinfo(struct cros_ec_device *ec_dev, uint8_t *data,
 408                                  int data_size)
 409 {
 410         int ret;
 411         struct cros_ec_command *msg;
 412
 413         if (!data || data_size <= 0 || data_size > ec_dev->max_response)
 414                 return -EINVAL;
 415
 416         msg = kzalloc(sizeof(*msg) + data_size, GFP_KERNEL);
 417         if (!msg)
 418                 return -ENOMEM;
 419
 420         msg->command = EC_CMD_GET_PANIC_INFO;
 421         msg->insize = data_size;
 422
 423         ret = cros_ec_cmd_xfer_status(ec_dev, msg);
 424         if (ret < 0)
 425                 goto free;
 426
 427         memcpy(data, msg->data, data_size);
 428
 429 free:
 430         kfree(msg);
 431         return ret;
 432 }
 433
 434 static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
 435 {
 436         struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
 437         int ret;
 438         void *data;
 439
 440         data = devm_kzalloc(debug_info->ec->dev, ec_dev->max_response,
 441                             GFP_KERNEL);
 442         if (!data)
 443                 return -ENOMEM;
 444
 445         ret = cros_ec_get_panicinfo(ec_dev, data, ec_dev->max_response);
 446         if (ret < 0) {
 447                 ret = 0;
 448                 goto free;
 449         }
 450
 451         /* No panic data */
 452         if (ret == 0)
 453                 goto free;
 454
 455         debug_info->panicinfo_blob.data = data;
 456         debug_info->panicinfo_blob.size = ret;
 457
 458         debugfs_create_blob("panicinfo", 0444, debug_info->dir,
 459                             &debug_info->panicinfo_blob);
 460
 461         return 0;
 462
 463 free:
 464         devm_kfree(debug_info->ec->dev, data);
 465         return ret;
 466 }
 467
 468 static int cros_ec_debugfs_panic_event(struct notifier_block *nb,
 469                                        unsigned long queued_during_suspend, void *_notify)
 470 {
 471         struct cros_ec_debugfs *debug_info =
 472                 container_of(nb, struct cros_ec_debugfs, notifier_panic);
 473
 474         if (debug_info->log_buffer.buf) {
 475                 /* Force log poll work to run immediately */
 476                 mod_delayed_work(debug_info->log_poll_work.wq, &debug_info->log_poll_work, 0);
 477                 /* Block until log poll work finishes */
 478                 flush_delayed_work(&debug_info->log_poll_work);
 479         }
 480
 481         return NOTIFY_DONE;
 482 }
 483
 484 static int cros_ec_debugfs_probe(struct platform_device *pd)
 485 {
 486         struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
 487         struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
 488         const char *name = ec_platform->ec_name;
 489         struct cros_ec_debugfs *debug_info;
 490         int ret;
 491
 492         debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
 493         if (!debug_info)
 494                 return -ENOMEM;
 495
 496         debug_info->ec = ec;
 497         debug_info->dir = debugfs_create_dir(name, NULL);
 498
 499         ret = cros_ec_create_panicinfo(debug_info);
 500         if (ret)
 501                 goto remove_debugfs;
 502
 503         ret = cros_ec_create_console_log(debug_info);
 504         if (ret)
 505                 goto remove_debugfs;
 506
 507         debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
 508                             &cros_ec_pdinfo_fops);
 509
 510         if (cros_ec_uptime_is_supported(ec->ec_dev))
 511                 debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
 512                                     &cros_ec_uptime_fops);
 513
 514         debugfs_create_x32("last_resume_result", 0444, debug_info->dir,
 515                            &ec->ec_dev->last_resume_result);
 516
 517         debugfs_create_u16("suspend_timeout_ms", 0664, debug_info->dir,
 518                            &ec->ec_dev->suspend_timeout_ms);
 519
 520         debug_info->notifier_panic.notifier_call = cros_ec_debugfs_panic_event;
 521         ret = blocking_notifier_chain_register(&ec->ec_dev->panic_notifier,
 522                                                &debug_info->notifier_panic);
 523         if (ret)
 524                 goto remove_debugfs;
 525
 526         ec->debug_info = debug_info;
 527
 528         dev_set_drvdata(&pd->dev, ec);
 529
 530         return 0;
 531
 532 remove_debugfs:
 533         debugfs_remove_recursive(debug_info->dir);
 534         return ret;
 535 }
 536
 537 static void cros_ec_debugfs_remove(struct platform_device *pd)
 538 {
 539         struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
 540
 541         debugfs_remove_recursive(ec->debug_info->dir);
 542         cros_ec_cleanup_console_log(ec->debug_info);
 543 }
 544
 545 static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
 546 {
 547         struct cros_ec_dev *ec = dev_get_drvdata(dev);
 548
 549         if (ec->debug_info->log_buffer.buf)
 550                 cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
 551
 552         return 0;
 553 }
 554
 555 static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
 556 {
 557         struct cros_ec_dev *ec = dev_get_drvdata(dev);
 558
 559         if (ec->debug_info->log_buffer.buf)
 560                 schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
 561
 562         return 0;
 563 }
 564
 565 static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
 566                          cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
 567
 568 static const struct platform_device_id cros_ec_debugfs_id[] = {
 569         { DRV_NAME, 0 },
 570         {}
 571 };
 572 MODULE_DEVICE_TABLE(platform, cros_ec_debugfs_id);
 573
 574 static struct platform_driver cros_ec_debugfs_driver = {
 575         .driver = {
 576                 .name = DRV_NAME,
 577                 .pm = &cros_ec_debugfs_pm_ops,
 578                 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
 579         },
 580         .probe = cros_ec_debugfs_probe,
 581         .remove_new = cros_ec_debugfs_remove,
 582         .id_table = cros_ec_debugfs_id,
 583 };
 584
 585 module_platform_driver(cros_ec_debugfs_driver);
 586
 587 MODULE_LICENSE("GPL");
 588 MODULE_DESCRIPTION("Debug logs for ChromeOS EC");