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