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