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