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