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 static unsigned int log_poll_period_ms = LOG_POLL_SEC * MSEC_PER_SEC;
  30 module_param(log_poll_period_ms, uint, 0644);
  31 MODULE_PARM_DESC(log_poll_period_ms, "EC log polling period(ms)");
  32
  33 /* waitqueue for log readers */
  34 static DECLARE_WAIT_QUEUE_HEAD(cros_ec_debugfs_log_wq);
  35
  36 /**
  37  * struct cros_ec_debugfs - EC debugging information.
  38  *
  39  * @ec: EC device this debugfs information belongs to
  40  * @dir: dentry for debugfs files
  41  * @log_buffer: circular buffer for console log information
  42  * @read_msg: preallocated EC command and buffer to read console log
  43  * @log_mutex: mutex to protect circular buffer
  44  * @log_poll_work: recurring task to poll EC for new console log data
  45  * @panicinfo_blob: panicinfo debugfs blob
  46  * @notifier_panic: notifier_block to let kernel to flush buffered log
  47  *                  when EC panic
  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         struct delayed_work log_poll_work;
  57         /* EC panicinfo */
  58         struct debugfs_blob_wrapper panicinfo_blob;
  59         struct notifier_block notifier_panic;
  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_period_ms.
  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_status(ec->ec_dev, &snapshot_msg);
  86         if (ret < 0)
  87                 goto resched;
  88
  89         /* Loop until we have read everything, or there's an error. */
  90         mutex_lock(&debug_info->log_mutex);
  91         buf_space = CIRC_SPACE(cb->head, cb->tail, LOG_SIZE);
  92
  93         while (1) {
  94                 if (!buf_space) {
  95                         dev_info_once(ec->dev,
  96                                       "Some logs may have been dropped...\n");
  97                         break;
  98                 }
  99
 100                 memset(read_params, '\0', sizeof(*read_params));
 101                 read_params->subcmd = CONSOLE_READ_RECENT;
 102                 ret = cros_ec_cmd_xfer_status(ec->ec_dev,
 103                                               debug_info->read_msg);
 104                 if (ret < 0)
 105                         break;
 106
 107                 /* If the buffer is empty, we're done here. */
 108                 if (ret == 0 || ec_buffer[0] == '\0')
 109                         break;
 110
 111                 idx = 0;
 112                 while (idx < ret && ec_buffer[idx] != '\0' && buf_space > 0) {
 113                         cb->buf[cb->head] = ec_buffer[idx];
 114                         cb->head = CIRC_ADD(cb->head, LOG_SIZE, 1);
 115                         idx++;
 116                         buf_space--;
 117                 }
 118
 119                 wake_up(&cros_ec_debugfs_log_wq);
 120         }
 121
 122         mutex_unlock(&debug_info->log_mutex);
 123
 124 resched:
 125         schedule_delayed_work(&debug_info->log_poll_work,
 126                               msecs_to_jiffies(log_poll_period_ms));
 127 }
 128
 129 static int cros_ec_console_log_open(struct inode *inode, struct file *file)
 130 {
 131         file->private_data = inode->i_private;
 132
 133         return stream_open(inode, file);
 134 }
 135
 136 static ssize_t cros_ec_console_log_read(struct file *file, char __user *buf,
 137                                         size_t count, loff_t *ppos)
 138 {
 139         struct cros_ec_debugfs *debug_info = file->private_data;
 140         struct circ_buf *cb = &debug_info->log_buffer;
 141         ssize_t ret;
 142
 143         mutex_lock(&debug_info->log_mutex);
 144
 145         while (!CIRC_CNT(cb->head, cb->tail, LOG_SIZE)) {
 146                 if (file->f_flags & O_NONBLOCK) {
 147                         ret = -EAGAIN;
 148                         goto error;
 149                 }
 150
 151                 mutex_unlock(&debug_info->log_mutex);
 152
 153                 ret = wait_event_interruptible(cros_ec_debugfs_log_wq,
 154                                         CIRC_CNT(cb->head, cb->tail, LOG_SIZE));
 155                 if (ret < 0)
 156                         return ret;
 157
 158                 mutex_lock(&debug_info->log_mutex);
 159         }
 160
 161         /* Only copy until the end of the circular buffer, and let userspace
 162          * retry to get the rest of the data.
 163          */
 164         ret = min_t(size_t, CIRC_CNT_TO_END(cb->head, cb->tail, LOG_SIZE),
 165                     count);
 166
 167         if (copy_to_user(buf, cb->buf + cb->tail, ret)) {
 168                 ret = -EFAULT;
 169                 goto error;
 170         }
 171
 172         cb->tail = CIRC_ADD(cb->tail, LOG_SIZE, ret);
 173
 174 error:
 175         mutex_unlock(&debug_info->log_mutex);
 176         return ret;
 177 }
 178
 179 static __poll_t cros_ec_console_log_poll(struct file *file,
 180                                              poll_table *wait)
 181 {
 182         struct cros_ec_debugfs *debug_info = file->private_data;
 183         __poll_t mask = 0;
 184
 185         poll_wait(file, &cros_ec_debugfs_log_wq, wait);
 186
 187         mutex_lock(&debug_info->log_mutex);
 188         if (CIRC_CNT(debug_info->log_buffer.head,
 189                      debug_info->log_buffer.tail,
 190                      LOG_SIZE))
 191                 mask |= EPOLLIN | EPOLLRDNORM;
 192         mutex_unlock(&debug_info->log_mutex);
 193
 194         return mask;
 195 }
 196
 197 static int cros_ec_console_log_release(struct inode *inode, struct file *file)
 198 {
 199         return 0;
 200 }
 201
 202 static ssize_t cros_ec_pdinfo_read(struct file *file,
 203                                    char __user *user_buf,
 204                                    size_t count,
 205                                    loff_t *ppos)
 206 {
 207         char read_buf[EC_USB_PD_MAX_PORTS * 40], *p = read_buf;
 208         struct cros_ec_debugfs *debug_info = file->private_data;
 209         struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
 210         struct {
 211                 struct cros_ec_command msg;
 212                 union {
 213                         struct ec_response_usb_pd_control_v1 resp;
 214                         struct ec_params_usb_pd_control params;
 215                 };
 216         } __packed ec_buf;
 217         struct cros_ec_command *msg;
 218         struct ec_response_usb_pd_control_v1 *resp;
 219         struct ec_params_usb_pd_control *params;
 220         int i;
 221
 222         msg = &ec_buf.msg;
 223         params = (struct ec_params_usb_pd_control *)msg->data;
 224         resp = (struct ec_response_usb_pd_control_v1 *)msg->data;
 225
 226         msg->command = EC_CMD_USB_PD_CONTROL;
 227         msg->version = 1;
 228         msg->insize = sizeof(*resp);
 229         msg->outsize = sizeof(*params);
 230
 231         /*
 232          * Read status from all PD ports until failure, typically caused
 233          * by attempting to read status on a port that doesn't exist.
 234          */
 235         for (i = 0; i < EC_USB_PD_MAX_PORTS; ++i) {
 236                 params->port = i;
 237                 params->role = 0;
 238                 params->mux = 0;
 239                 params->swap = 0;
 240
 241                 if (cros_ec_cmd_xfer_status(ec_dev, msg) < 0)
 242                         break;
 243
 244                 p += scnprintf(p, sizeof(read_buf) + read_buf - p,
 245                                "p%d: %s en:%.2x role:%.2x pol:%.2x\n", i,
 246                                resp->state, resp->enabled, resp->role,
 247                                resp->polarity);
 248         }
 249
 250         return simple_read_from_buffer(user_buf, count, ppos,
 251                                        read_buf, p - read_buf);
 252 }
 253
 254 static bool cros_ec_uptime_is_supported(struct cros_ec_device *ec_dev)
 255 {
 256         struct {
 257                 struct cros_ec_command cmd;
 258                 struct ec_response_uptime_info resp;
 259         } __packed msg = {};
 260         int ret;
 261
 262         msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
 263         msg.cmd.insize = sizeof(msg.resp);
 264
 265         ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
 266         if (ret == -EPROTO && msg.cmd.result == EC_RES_INVALID_COMMAND)
 267                 return false;
 268
 269         /* Other errors maybe a transient error, do not rule about support. */
 270         return true;
 271 }
 272
 273 static ssize_t cros_ec_uptime_read(struct file *file, char __user *user_buf,
 274                                    size_t count, loff_t *ppos)
 275 {
 276         struct cros_ec_debugfs *debug_info = file->private_data;
 277         struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
 278         struct {
 279                 struct cros_ec_command cmd;
 280                 struct ec_response_uptime_info resp;
 281         } __packed msg = {};
 282         struct ec_response_uptime_info *resp;
 283         char read_buf[32];
 284         int ret;
 285
 286         resp = (struct ec_response_uptime_info *)&msg.resp;
 287
 288         msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
 289         msg.cmd.insize = sizeof(*resp);
 290
 291         ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
 292         if (ret < 0)
 293                 return ret;
 294
 295         ret = scnprintf(read_buf, sizeof(read_buf), "%u\n",
 296                         resp->time_since_ec_boot_ms);
 297
 298         return simple_read_from_buffer(user_buf, count, ppos, read_buf, ret);
 299 }
 300
 301 static const struct file_operations cros_ec_console_log_fops = {
 302         .owner = THIS_MODULE,
 303         .open = cros_ec_console_log_open,
 304         .read = cros_ec_console_log_read,
 305         .poll = cros_ec_console_log_poll,
 306         .release = cros_ec_console_log_release,
 307 };
 308
 309 static const struct file_operations cros_ec_pdinfo_fops = {
 310         .owner = THIS_MODULE,
 311         .open = simple_open,
 312         .read = cros_ec_pdinfo_read,
 313         .llseek = default_llseek,
 314 };
 315
 316 static const struct file_operations cros_ec_uptime_fops = {
 317         .owner = THIS_MODULE,
 318         .open = simple_open,
 319         .read = cros_ec_uptime_read,
 320         .llseek = default_llseek,
 321 };
 322
 323 static int ec_read_version_supported(struct cros_ec_dev *ec)
 324 {
 325         struct ec_params_get_cmd_versions_v1 *params;
 326         struct ec_response_get_cmd_versions *response;
 327         int ret;
 328
 329         struct cros_ec_command *msg;
 330
 331         msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
 332                 GFP_KERNEL);
 333         if (!msg)
 334                 return 0;
 335
 336         msg->version = 1;
 337         msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
 338         msg->outsize = sizeof(*params);
 339         msg->insize = sizeof(*response);
 340
 341         params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
 342         params->cmd = EC_CMD_CONSOLE_READ;
 343         response = (struct ec_response_get_cmd_versions *)msg->data;
 344
 345         ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg) >= 0 &&
 346               response->version_mask & EC_VER_MASK(1);
 347
 348         kfree(msg);
 349
 350         return ret;
 351 }
 352
 353 static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
 354 {
 355         struct cros_ec_dev *ec = debug_info->ec;
 356         char *buf;
 357         int read_params_size;
 358         int read_response_size;
 359
 360         /*
 361          * If the console log feature is not supported return silently and
 362          * don't create the console_log entry.
 363          */
 364         if (!ec_read_version_supported(ec))
 365                 return 0;
 366
 367         buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
 368         if (!buf)
 369                 return -ENOMEM;
 370
 371         read_params_size = sizeof(struct ec_params_console_read_v1);
 372         read_response_size = ec->ec_dev->max_response;
 373         debug_info->read_msg = devm_kzalloc(ec->dev,
 374                 sizeof(*debug_info->read_msg) +
 375                         max(read_params_size, read_response_size), GFP_KERNEL);
 376         if (!debug_info->read_msg)
 377                 return -ENOMEM;
 378
 379         debug_info->read_msg->version = 1;
 380         debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
 381         debug_info->read_msg->outsize = read_params_size;
 382         debug_info->read_msg->insize = read_response_size;
 383
 384         debug_info->log_buffer.buf = buf;
 385         debug_info->log_buffer.head = 0;
 386         debug_info->log_buffer.tail = 0;
 387
 388         mutex_init(&debug_info->log_mutex);
 389
 390         debugfs_create_file("console_log", S_IFREG | 0444, debug_info->dir,
 391                             debug_info, &cros_ec_console_log_fops);
 392
 393         INIT_DELAYED_WORK(&debug_info->log_poll_work,
 394                           cros_ec_console_log_work);
 395         schedule_delayed_work(&debug_info->log_poll_work, 0);
 396
 397         return 0;
 398 }
 399
 400 static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
 401 {
 402         if (debug_info->log_buffer.buf) {
 403                 cancel_delayed_work_sync(&debug_info->log_poll_work);
 404                 mutex_destroy(&debug_info->log_mutex);
 405         }
 406 }
 407
 408 /*
 409  * Returns the size of the panicinfo data fetched from the EC
 410  */
 411 static int cros_ec_get_panicinfo(struct cros_ec_device *ec_dev, uint8_t *data,
 412                                  int data_size)
 413 {
 414         int ret;
 415         struct cros_ec_command *msg;
 416
 417         if (!data || data_size <= 0 || data_size > ec_dev->max_response)
 418                 return -EINVAL;
 419
 420         msg = kzalloc(sizeof(*msg) + data_size, GFP_KERNEL);
 421         if (!msg)
 422                 return -ENOMEM;
 423
 424         msg->command = EC_CMD_GET_PANIC_INFO;
 425         msg->insize = data_size;
 426
 427         ret = cros_ec_cmd_xfer_status(ec_dev, msg);
 428         if (ret < 0)
 429                 goto free;
 430
 431         memcpy(data, msg->data, data_size);
 432
 433 free:
 434         kfree(msg);
 435         return ret;
 436 }
 437
 438 static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
 439 {
 440         struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
 441         int ret;
 442         void *data;
 443
 444         data = devm_kzalloc(debug_info->ec->dev, ec_dev->max_response,
 445                             GFP_KERNEL);
 446         if (!data)
 447                 return -ENOMEM;
 448
 449         ret = cros_ec_get_panicinfo(ec_dev, data, ec_dev->max_response);
 450         if (ret < 0) {
 451                 ret = 0;
 452                 goto free;
 453         }
 454
 455         /* No panic data */
 456         if (ret == 0)
 457                 goto free;
 458
 459         debug_info->panicinfo_blob.data = data;
 460         debug_info->panicinfo_blob.size = ret;
 461
 462         debugfs_create_blob("panicinfo", 0444, debug_info->dir,
 463                             &debug_info->panicinfo_blob);
 464
 465         return 0;
 466
 467 free:
 468         devm_kfree(debug_info->ec->dev, data);
 469         return ret;
 470 }
 471
 472 static int cros_ec_debugfs_panic_event(struct notifier_block *nb,
 473                                        unsigned long queued_during_suspend, void *_notify)
 474 {
 475         struct cros_ec_debugfs *debug_info =
 476                 container_of(nb, struct cros_ec_debugfs, notifier_panic);
 477
 478         if (debug_info->log_buffer.buf) {
 479                 /* Force log poll work to run immediately */
 480                 mod_delayed_work(debug_info->log_poll_work.wq, &debug_info->log_poll_work, 0);
 481                 /* Block until log poll work finishes */
 482                 flush_delayed_work(&debug_info->log_poll_work);
 483         }
 484
 485         return NOTIFY_DONE;
 486 }
 487
 488 static int cros_ec_debugfs_probe(struct platform_device *pd)
 489 {
 490         struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
 491         struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
 492         const char *name = ec_platform->ec_name;
 493         struct cros_ec_debugfs *debug_info;
 494         int ret;
 495
 496         debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
 497         if (!debug_info)
 498                 return -ENOMEM;
 499
 500         debug_info->ec = ec;
 501         debug_info->dir = debugfs_create_dir(name, NULL);
 502
 503         ret = cros_ec_create_panicinfo(debug_info);
 504         if (ret)
 505                 goto remove_debugfs;
 506
 507         ret = cros_ec_create_console_log(debug_info);
 508         if (ret)
 509                 goto remove_debugfs;
 510
 511         debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
 512                             &cros_ec_pdinfo_fops);
 513
 514         if (cros_ec_uptime_is_supported(ec->ec_dev))
 515                 debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
 516                                     &cros_ec_uptime_fops);
 517
 518         debugfs_create_x32("last_resume_result", 0444, debug_info->dir,
 519                            &ec->ec_dev->last_resume_result);
 520
 521         debugfs_create_u16("suspend_timeout_ms", 0664, debug_info->dir,
 522                            &ec->ec_dev->suspend_timeout_ms);
 523
 524         debug_info->notifier_panic.notifier_call = cros_ec_debugfs_panic_event;
 525         ret = blocking_notifier_chain_register(&ec->ec_dev->panic_notifier,
 526                                                &debug_info->notifier_panic);
 527         if (ret)
 528                 goto remove_debugfs;
 529
 530         ec->debug_info = debug_info;
 531
 532         dev_set_drvdata(&pd->dev, ec);
 533
 534         return 0;
 535
 536 remove_debugfs:
 537         debugfs_remove_recursive(debug_info->dir);
 538         return ret;
 539 }
 540
 541 static void cros_ec_debugfs_remove(struct platform_device *pd)
 542 {
 543         struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
 544
 545         debugfs_remove_recursive(ec->debug_info->dir);
 546         cros_ec_cleanup_console_log(ec->debug_info);
 547 }
 548
 549 static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
 550 {
 551         struct cros_ec_dev *ec = dev_get_drvdata(dev);
 552
 553         if (ec->debug_info->log_buffer.buf)
 554                 cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
 555
 556         return 0;
 557 }
 558
 559 static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
 560 {
 561         struct cros_ec_dev *ec = dev_get_drvdata(dev);
 562
 563         if (ec->debug_info->log_buffer.buf)
 564                 schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
 565
 566         return 0;
 567 }
 568
 569 static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
 570                          cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
 571
 572 static const struct platform_device_id cros_ec_debugfs_id[] = {
 573         { DRV_NAME, 0 },
 574         {}
 575 };
 576 MODULE_DEVICE_TABLE(platform, cros_ec_debugfs_id);
 577
 578 static struct platform_driver cros_ec_debugfs_driver = {
 579         .driver = {
 580                 .name = DRV_NAME,
 581                 .pm = &cros_ec_debugfs_pm_ops,
 582                 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
 583         },
 584         .probe = cros_ec_debugfs_probe,
 585         .remove = cros_ec_debugfs_remove,
 586         .id_table = cros_ec_debugfs_id,
 587 };
 588
 589 module_platform_driver(cros_ec_debugfs_driver);
 590
 591 MODULE_LICENSE("GPL");
 592 MODULE_DESCRIPTION("Debug logs for ChromeOS EC");