1 /* 2 * ACPI AML interfacing support 3 * 4 * Copyright (C) 2015, Intel Corporation 5 * Authors: Lv Zheng <lv.zheng@intel.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 12 /* #define DEBUG */ 13 #define pr_fmt(fmt) "ACPI: AML: " fmt 14 15 #include <linux/kernel.h> 16 #include <linux/module.h> 17 #include <linux/wait.h> 18 #include <linux/poll.h> 19 #include <linux/sched.h> 20 #include <linux/kthread.h> 21 #include <linux/proc_fs.h> 22 #include <linux/debugfs.h> 23 #include <linux/circ_buf.h> 24 #include <linux/acpi.h> 25 #include "internal.h" 26 27 #define ACPI_AML_BUF_ALIGN (sizeof (acpi_size)) 28 #define ACPI_AML_BUF_SIZE PAGE_SIZE 29 30 #define circ_count(circ) \ 31 (CIRC_CNT((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE)) 32 #define circ_count_to_end(circ) \ 33 (CIRC_CNT_TO_END((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE)) 34 #define circ_space(circ) \ 35 (CIRC_SPACE((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE)) 36 #define circ_space_to_end(circ) \ 37 (CIRC_SPACE_TO_END((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE)) 38 39 #define ACPI_AML_OPENED 0x0001 40 #define ACPI_AML_CLOSED 0x0002 41 #define ACPI_AML_IN_USER 0x0004 /* user space is writing cmd */ 42 #define ACPI_AML_IN_KERN 0x0008 /* kernel space is reading cmd */ 43 #define ACPI_AML_OUT_USER 0x0010 /* user space is reading log */ 44 #define ACPI_AML_OUT_KERN 0x0020 /* kernel space is writing log */ 45 #define ACPI_AML_USER (ACPI_AML_IN_USER | ACPI_AML_OUT_USER) 46 #define ACPI_AML_KERN (ACPI_AML_IN_KERN | ACPI_AML_OUT_KERN) 47 #define ACPI_AML_BUSY (ACPI_AML_USER | ACPI_AML_KERN) 48 #define ACPI_AML_OPEN (ACPI_AML_OPENED | ACPI_AML_CLOSED) 49 50 struct acpi_aml_io { 51 wait_queue_head_t wait; 52 unsigned long flags; 53 unsigned long users; 54 struct mutex lock; 55 struct task_struct *thread; 56 char out_buf[ACPI_AML_BUF_SIZE] __aligned(ACPI_AML_BUF_ALIGN); 57 struct circ_buf out_crc; 58 char in_buf[ACPI_AML_BUF_SIZE] __aligned(ACPI_AML_BUF_ALIGN); 59 struct circ_buf in_crc; 60 acpi_osd_exec_callback function; 61 void *context; 62 unsigned long usages; 63 }; 64 65 static struct acpi_aml_io acpi_aml_io; 66 static bool acpi_aml_initialized; 67 static struct file *acpi_aml_active_reader; 68 static struct dentry *acpi_aml_dentry; 69 70 static inline bool __acpi_aml_running(void) 71 { 72 return acpi_aml_io.thread ? true : false; 73 } 74 75 static inline bool __acpi_aml_access_ok(unsigned long flag) 76 { 77 /* 78 * The debugger interface is in opened state (OPENED && !CLOSED), 79 * then it is allowed to access the debugger buffers from either 80 * user space or the kernel space. 81 * In addition, for the kernel space, only the debugger thread 82 * (thread ID matched) is allowed to access. 83 */ 84 if (!(acpi_aml_io.flags & ACPI_AML_OPENED) || 85 (acpi_aml_io.flags & ACPI_AML_CLOSED) || 86 !__acpi_aml_running()) 87 return false; 88 if ((flag & ACPI_AML_KERN) && 89 current != acpi_aml_io.thread) 90 return false; 91 return true; 92 } 93 94 static inline bool __acpi_aml_readable(struct circ_buf *circ, unsigned long flag) 95 { 96 /* 97 * Another read is not in progress and there is data in buffer 98 * available for read. 99 */ 100 if (!(acpi_aml_io.flags & flag) && circ_count(circ)) 101 return true; 102 return false; 103 } 104 105 static inline bool __acpi_aml_writable(struct circ_buf *circ, unsigned long flag) 106 { 107 /* 108 * Another write is not in progress and there is buffer space 109 * available for write. 110 */ 111 if (!(acpi_aml_io.flags & flag) && circ_space(circ)) 112 return true; 113 return false; 114 } 115 116 static inline bool __acpi_aml_busy(void) 117 { 118 if (acpi_aml_io.flags & ACPI_AML_BUSY) 119 return true; 120 return false; 121 } 122 123 static inline bool __acpi_aml_opened(void) 124 { 125 if (acpi_aml_io.flags & ACPI_AML_OPEN) 126 return true; 127 return false; 128 } 129 130 static inline bool __acpi_aml_used(void) 131 { 132 return acpi_aml_io.usages ? true : false; 133 } 134 135 static inline bool acpi_aml_running(void) 136 { 137 bool ret; 138 139 mutex_lock(&acpi_aml_io.lock); 140 ret = __acpi_aml_running(); 141 mutex_unlock(&acpi_aml_io.lock); 142 return ret; 143 } 144 145 static bool acpi_aml_busy(void) 146 { 147 bool ret; 148 149 mutex_lock(&acpi_aml_io.lock); 150 ret = __acpi_aml_busy(); 151 mutex_unlock(&acpi_aml_io.lock); 152 return ret; 153 } 154 155 static bool acpi_aml_used(void) 156 { 157 bool ret; 158 159 /* 160 * The usage count is prepared to avoid race conditions between the 161 * starts and the stops of the debugger thread. 162 */ 163 mutex_lock(&acpi_aml_io.lock); 164 ret = __acpi_aml_used(); 165 mutex_unlock(&acpi_aml_io.lock); 166 return ret; 167 } 168 169 static bool acpi_aml_kern_readable(void) 170 { 171 bool ret; 172 173 mutex_lock(&acpi_aml_io.lock); 174 ret = !__acpi_aml_access_ok(ACPI_AML_IN_KERN) || 175 __acpi_aml_readable(&acpi_aml_io.in_crc, ACPI_AML_IN_KERN); 176 mutex_unlock(&acpi_aml_io.lock); 177 return ret; 178 } 179 180 static bool acpi_aml_kern_writable(void) 181 { 182 bool ret; 183 184 mutex_lock(&acpi_aml_io.lock); 185 ret = !__acpi_aml_access_ok(ACPI_AML_OUT_KERN) || 186 __acpi_aml_writable(&acpi_aml_io.out_crc, ACPI_AML_OUT_KERN); 187 mutex_unlock(&acpi_aml_io.lock); 188 return ret; 189 } 190 191 static bool acpi_aml_user_readable(void) 192 { 193 bool ret; 194 195 mutex_lock(&acpi_aml_io.lock); 196 ret = !__acpi_aml_access_ok(ACPI_AML_OUT_USER) || 197 __acpi_aml_readable(&acpi_aml_io.out_crc, ACPI_AML_OUT_USER); 198 mutex_unlock(&acpi_aml_io.lock); 199 return ret; 200 } 201 202 static bool acpi_aml_user_writable(void) 203 { 204 bool ret; 205 206 mutex_lock(&acpi_aml_io.lock); 207 ret = !__acpi_aml_access_ok(ACPI_AML_IN_USER) || 208 __acpi_aml_writable(&acpi_aml_io.in_crc, ACPI_AML_IN_USER); 209 mutex_unlock(&acpi_aml_io.lock); 210 return ret; 211 } 212 213 static int acpi_aml_lock_write(struct circ_buf *circ, unsigned long flag) 214 { 215 int ret = 0; 216 217 mutex_lock(&acpi_aml_io.lock); 218 if (!__acpi_aml_access_ok(flag)) { 219 ret = -EFAULT; 220 goto out; 221 } 222 if (!__acpi_aml_writable(circ, flag)) { 223 ret = -EAGAIN; 224 goto out; 225 } 226 acpi_aml_io.flags |= flag; 227 out: 228 mutex_unlock(&acpi_aml_io.lock); 229 return ret; 230 } 231 232 static int acpi_aml_lock_read(struct circ_buf *circ, unsigned long flag) 233 { 234 int ret = 0; 235 236 mutex_lock(&acpi_aml_io.lock); 237 if (!__acpi_aml_access_ok(flag)) { 238 ret = -EFAULT; 239 goto out; 240 } 241 if (!__acpi_aml_readable(circ, flag)) { 242 ret = -EAGAIN; 243 goto out; 244 } 245 acpi_aml_io.flags |= flag; 246 out: 247 mutex_unlock(&acpi_aml_io.lock); 248 return ret; 249 } 250 251 static void acpi_aml_unlock_fifo(unsigned long flag, bool wakeup) 252 { 253 mutex_lock(&acpi_aml_io.lock); 254 acpi_aml_io.flags &= ~flag; 255 if (wakeup) 256 wake_up_interruptible(&acpi_aml_io.wait); 257 mutex_unlock(&acpi_aml_io.lock); 258 } 259 260 static int acpi_aml_write_kern(const char *buf, int len) 261 { 262 int ret; 263 struct circ_buf *crc = &acpi_aml_io.out_crc; 264 int n; 265 char *p; 266 267 ret = acpi_aml_lock_write(crc, ACPI_AML_OUT_KERN); 268 if (ret < 0) 269 return ret; 270 /* sync tail before inserting logs */ 271 smp_mb(); 272 p = &crc->buf[crc->head]; 273 n = min(len, circ_space_to_end(crc)); 274 memcpy(p, buf, n); 275 /* sync head after inserting logs */ 276 smp_wmb(); 277 crc->head = (crc->head + n) & (ACPI_AML_BUF_SIZE - 1); 278 acpi_aml_unlock_fifo(ACPI_AML_OUT_KERN, true); 279 return n; 280 } 281 282 static int acpi_aml_readb_kern(void) 283 { 284 int ret; 285 struct circ_buf *crc = &acpi_aml_io.in_crc; 286 char *p; 287 288 ret = acpi_aml_lock_read(crc, ACPI_AML_IN_KERN); 289 if (ret < 0) 290 return ret; 291 /* sync head before removing cmds */ 292 smp_rmb(); 293 p = &crc->buf[crc->tail]; 294 ret = (int)*p; 295 /* sync tail before inserting cmds */ 296 smp_mb(); 297 crc->tail = (crc->tail + 1) & (ACPI_AML_BUF_SIZE - 1); 298 acpi_aml_unlock_fifo(ACPI_AML_IN_KERN, true); 299 return ret; 300 } 301 302 /* 303 * acpi_aml_write_log() - Capture debugger output 304 * @msg: the debugger output 305 * 306 * This function should be used to implement acpi_os_printf() to filter out 307 * the debugger output and store the output into the debugger interface 308 * buffer. Return the size of stored logs or errno. 309 */ 310 static ssize_t acpi_aml_write_log(const char *msg) 311 { 312 int ret = 0; 313 int count = 0, size = 0; 314 315 if (!acpi_aml_initialized) 316 return -ENODEV; 317 if (msg) 318 count = strlen(msg); 319 while (count > 0) { 320 again: 321 ret = acpi_aml_write_kern(msg + size, count); 322 if (ret == -EAGAIN) { 323 ret = wait_event_interruptible(acpi_aml_io.wait, 324 acpi_aml_kern_writable()); 325 /* 326 * We need to retry when the condition 327 * becomes true. 328 */ 329 if (ret == 0) 330 goto again; 331 break; 332 } 333 if (ret < 0) 334 break; 335 size += ret; 336 count -= ret; 337 } 338 return size > 0 ? size : ret; 339 } 340 341 /* 342 * acpi_aml_read_cmd() - Capture debugger input 343 * @msg: the debugger input 344 * @size: the size of the debugger input 345 * 346 * This function should be used to implement acpi_os_get_line() to capture 347 * the debugger input commands and store the input commands into the 348 * debugger interface buffer. Return the size of stored commands or errno. 349 */ 350 static ssize_t acpi_aml_read_cmd(char *msg, size_t count) 351 { 352 int ret = 0; 353 int size = 0; 354 355 /* 356 * This is ensured by the running fact of the debugger thread 357 * unless a bug is introduced. 358 */ 359 BUG_ON(!acpi_aml_initialized); 360 while (count > 0) { 361 again: 362 /* 363 * Check each input byte to find the end of the command. 364 */ 365 ret = acpi_aml_readb_kern(); 366 if (ret == -EAGAIN) { 367 ret = wait_event_interruptible(acpi_aml_io.wait, 368 acpi_aml_kern_readable()); 369 /* 370 * We need to retry when the condition becomes 371 * true. 372 */ 373 if (ret == 0) 374 goto again; 375 } 376 if (ret < 0) 377 break; 378 *(msg + size) = (char)ret; 379 size++; 380 count--; 381 if (ret == '\n') { 382 /* 383 * acpi_os_get_line() requires a zero terminated command 384 * string. 385 */ 386 *(msg + size - 1) = '\0'; 387 break; 388 } 389 } 390 return size > 0 ? size : ret; 391 } 392 393 static int acpi_aml_thread(void *unsed) 394 { 395 acpi_osd_exec_callback function = NULL; 396 void *context; 397 398 mutex_lock(&acpi_aml_io.lock); 399 if (acpi_aml_io.function) { 400 acpi_aml_io.usages++; 401 function = acpi_aml_io.function; 402 context = acpi_aml_io.context; 403 } 404 mutex_unlock(&acpi_aml_io.lock); 405 406 if (function) 407 function(context); 408 409 mutex_lock(&acpi_aml_io.lock); 410 acpi_aml_io.usages--; 411 if (!__acpi_aml_used()) { 412 acpi_aml_io.thread = NULL; 413 wake_up(&acpi_aml_io.wait); 414 } 415 mutex_unlock(&acpi_aml_io.lock); 416 417 return 0; 418 } 419 420 /* 421 * acpi_aml_create_thread() - Create AML debugger thread 422 * @function: the debugger thread callback 423 * @context: the context to be passed to the debugger thread 424 * 425 * This function should be used to implement acpi_os_execute() which is 426 * used by the ACPICA debugger to create the debugger thread. 427 */ 428 static int acpi_aml_create_thread(acpi_osd_exec_callback function, void *context) 429 { 430 struct task_struct *t; 431 432 mutex_lock(&acpi_aml_io.lock); 433 acpi_aml_io.function = function; 434 acpi_aml_io.context = context; 435 mutex_unlock(&acpi_aml_io.lock); 436 437 t = kthread_create(acpi_aml_thread, NULL, "aml"); 438 if (IS_ERR(t)) { 439 pr_err("Failed to create AML debugger thread.\n"); 440 return PTR_ERR(t); 441 } 442 443 mutex_lock(&acpi_aml_io.lock); 444 acpi_aml_io.thread = t; 445 acpi_set_debugger_thread_id((acpi_thread_id)(unsigned long)t); 446 wake_up_process(t); 447 mutex_unlock(&acpi_aml_io.lock); 448 return 0; 449 } 450 451 static int acpi_aml_wait_command_ready(bool single_step, 452 char *buffer, size_t length) 453 { 454 acpi_status status; 455 456 if (single_step) 457 acpi_os_printf("\n%1c ", ACPI_DEBUGGER_EXECUTE_PROMPT); 458 else 459 acpi_os_printf("\n%1c ", ACPI_DEBUGGER_COMMAND_PROMPT); 460 461 status = acpi_os_get_line(buffer, length, NULL); 462 if (ACPI_FAILURE(status)) 463 return -EINVAL; 464 return 0; 465 } 466 467 static int acpi_aml_notify_command_complete(void) 468 { 469 return 0; 470 } 471 472 static int acpi_aml_open(struct inode *inode, struct file *file) 473 { 474 int ret = 0; 475 acpi_status status; 476 477 mutex_lock(&acpi_aml_io.lock); 478 /* 479 * The debugger interface is being closed, no new user is allowed 480 * during this period. 481 */ 482 if (acpi_aml_io.flags & ACPI_AML_CLOSED) { 483 ret = -EBUSY; 484 goto err_lock; 485 } 486 if ((file->f_flags & O_ACCMODE) != O_WRONLY) { 487 /* 488 * Only one reader is allowed to initiate the debugger 489 * thread. 490 */ 491 if (acpi_aml_active_reader) { 492 ret = -EBUSY; 493 goto err_lock; 494 } else { 495 pr_debug("Opening debugger reader.\n"); 496 acpi_aml_active_reader = file; 497 } 498 } else { 499 /* 500 * No writer is allowed unless the debugger thread is 501 * ready. 502 */ 503 if (!(acpi_aml_io.flags & ACPI_AML_OPENED)) { 504 ret = -ENODEV; 505 goto err_lock; 506 } 507 } 508 if (acpi_aml_active_reader == file) { 509 pr_debug("Opening debugger interface.\n"); 510 mutex_unlock(&acpi_aml_io.lock); 511 512 pr_debug("Initializing debugger thread.\n"); 513 status = acpi_initialize_debugger(); 514 if (ACPI_FAILURE(status)) { 515 pr_err("Failed to initialize debugger.\n"); 516 ret = -EINVAL; 517 goto err_exit; 518 } 519 pr_debug("Debugger thread initialized.\n"); 520 521 mutex_lock(&acpi_aml_io.lock); 522 acpi_aml_io.flags |= ACPI_AML_OPENED; 523 acpi_aml_io.out_crc.head = acpi_aml_io.out_crc.tail = 0; 524 acpi_aml_io.in_crc.head = acpi_aml_io.in_crc.tail = 0; 525 pr_debug("Debugger interface opened.\n"); 526 } 527 acpi_aml_io.users++; 528 err_lock: 529 if (ret < 0) { 530 if (acpi_aml_active_reader == file) 531 acpi_aml_active_reader = NULL; 532 } 533 mutex_unlock(&acpi_aml_io.lock); 534 err_exit: 535 return ret; 536 } 537 538 static int acpi_aml_release(struct inode *inode, struct file *file) 539 { 540 mutex_lock(&acpi_aml_io.lock); 541 acpi_aml_io.users--; 542 if (file == acpi_aml_active_reader) { 543 pr_debug("Closing debugger reader.\n"); 544 acpi_aml_active_reader = NULL; 545 546 pr_debug("Closing debugger interface.\n"); 547 acpi_aml_io.flags |= ACPI_AML_CLOSED; 548 549 /* 550 * Wake up all user space/kernel space blocked 551 * readers/writers. 552 */ 553 wake_up_interruptible(&acpi_aml_io.wait); 554 mutex_unlock(&acpi_aml_io.lock); 555 /* 556 * Wait all user space/kernel space readers/writers to 557 * stop so that ACPICA command loop of the debugger thread 558 * should fail all its command line reads after this point. 559 */ 560 wait_event(acpi_aml_io.wait, !acpi_aml_busy()); 561 562 /* 563 * Then we try to terminate the debugger thread if it is 564 * not terminated. 565 */ 566 pr_debug("Terminating debugger thread.\n"); 567 acpi_terminate_debugger(); 568 wait_event(acpi_aml_io.wait, !acpi_aml_used()); 569 pr_debug("Debugger thread terminated.\n"); 570 571 mutex_lock(&acpi_aml_io.lock); 572 acpi_aml_io.flags &= ~ACPI_AML_OPENED; 573 } 574 if (acpi_aml_io.users == 0) { 575 pr_debug("Debugger interface closed.\n"); 576 acpi_aml_io.flags &= ~ACPI_AML_CLOSED; 577 } 578 mutex_unlock(&acpi_aml_io.lock); 579 return 0; 580 } 581 582 static int acpi_aml_read_user(char __user *buf, int len) 583 { 584 int ret; 585 struct circ_buf *crc = &acpi_aml_io.out_crc; 586 int n; 587 char *p; 588 589 ret = acpi_aml_lock_read(crc, ACPI_AML_OUT_USER); 590 if (ret < 0) 591 return ret; 592 /* sync head before removing logs */ 593 smp_rmb(); 594 p = &crc->buf[crc->tail]; 595 n = min(len, circ_count_to_end(crc)); 596 if (copy_to_user(buf, p, n)) { 597 ret = -EFAULT; 598 goto out; 599 } 600 /* sync tail after removing logs */ 601 smp_mb(); 602 crc->tail = (crc->tail + n) & (ACPI_AML_BUF_SIZE - 1); 603 ret = n; 604 out: 605 acpi_aml_unlock_fifo(ACPI_AML_OUT_USER, ret >= 0); 606 return ret; 607 } 608 609 static ssize_t acpi_aml_read(struct file *file, char __user *buf, 610 size_t count, loff_t *ppos) 611 { 612 int ret = 0; 613 int size = 0; 614 615 if (!count) 616 return 0; 617 if (!access_ok(VERIFY_WRITE, buf, count)) 618 return -EFAULT; 619 620 while (count > 0) { 621 again: 622 ret = acpi_aml_read_user(buf + size, count); 623 if (ret == -EAGAIN) { 624 if (file->f_flags & O_NONBLOCK) 625 break; 626 else { 627 ret = wait_event_interruptible(acpi_aml_io.wait, 628 acpi_aml_user_readable()); 629 /* 630 * We need to retry when the condition 631 * becomes true. 632 */ 633 if (ret == 0) 634 goto again; 635 } 636 } 637 if (ret < 0) { 638 if (!acpi_aml_running()) 639 ret = 0; 640 break; 641 } 642 if (ret) { 643 size += ret; 644 count -= ret; 645 *ppos += ret; 646 break; 647 } 648 } 649 return size > 0 ? size : ret; 650 } 651 652 static int acpi_aml_write_user(const char __user *buf, int len) 653 { 654 int ret; 655 struct circ_buf *crc = &acpi_aml_io.in_crc; 656 int n; 657 char *p; 658 659 ret = acpi_aml_lock_write(crc, ACPI_AML_IN_USER); 660 if (ret < 0) 661 return ret; 662 /* sync tail before inserting cmds */ 663 smp_mb(); 664 p = &crc->buf[crc->head]; 665 n = min(len, circ_space_to_end(crc)); 666 if (copy_from_user(p, buf, n)) { 667 ret = -EFAULT; 668 goto out; 669 } 670 /* sync head after inserting cmds */ 671 smp_wmb(); 672 crc->head = (crc->head + n) & (ACPI_AML_BUF_SIZE - 1); 673 ret = n; 674 out: 675 acpi_aml_unlock_fifo(ACPI_AML_IN_USER, ret >= 0); 676 return n; 677 } 678 679 static ssize_t acpi_aml_write(struct file *file, const char __user *buf, 680 size_t count, loff_t *ppos) 681 { 682 int ret = 0; 683 int size = 0; 684 685 if (!count) 686 return 0; 687 if (!access_ok(VERIFY_READ, buf, count)) 688 return -EFAULT; 689 690 while (count > 0) { 691 again: 692 ret = acpi_aml_write_user(buf + size, count); 693 if (ret == -EAGAIN) { 694 if (file->f_flags & O_NONBLOCK) 695 break; 696 else { 697 ret = wait_event_interruptible(acpi_aml_io.wait, 698 acpi_aml_user_writable()); 699 /* 700 * We need to retry when the condition 701 * becomes true. 702 */ 703 if (ret == 0) 704 goto again; 705 } 706 } 707 if (ret < 0) { 708 if (!acpi_aml_running()) 709 ret = 0; 710 break; 711 } 712 if (ret) { 713 size += ret; 714 count -= ret; 715 *ppos += ret; 716 } 717 } 718 return size > 0 ? size : ret; 719 } 720 721 static __poll_t acpi_aml_poll(struct file *file, poll_table *wait) 722 { 723 __poll_t masks = 0; 724 725 poll_wait(file, &acpi_aml_io.wait, wait); 726 if (acpi_aml_user_readable()) 727 masks |= EPOLLIN | EPOLLRDNORM; 728 if (acpi_aml_user_writable()) 729 masks |= EPOLLOUT | EPOLLWRNORM; 730 731 return masks; 732 } 733 734 static const struct file_operations acpi_aml_operations = { 735 .read = acpi_aml_read, 736 .write = acpi_aml_write, 737 .poll = acpi_aml_poll, 738 .open = acpi_aml_open, 739 .release = acpi_aml_release, 740 .llseek = generic_file_llseek, 741 }; 742 743 static const struct acpi_debugger_ops acpi_aml_debugger = { 744 .create_thread = acpi_aml_create_thread, 745 .read_cmd = acpi_aml_read_cmd, 746 .write_log = acpi_aml_write_log, 747 .wait_command_ready = acpi_aml_wait_command_ready, 748 .notify_command_complete = acpi_aml_notify_command_complete, 749 }; 750 751 int __init acpi_aml_init(void) 752 { 753 int ret = 0; 754 755 if (!acpi_debugfs_dir) { 756 ret = -ENOENT; 757 goto err_exit; 758 } 759 760 /* Initialize AML IO interface */ 761 mutex_init(&acpi_aml_io.lock); 762 init_waitqueue_head(&acpi_aml_io.wait); 763 acpi_aml_io.out_crc.buf = acpi_aml_io.out_buf; 764 acpi_aml_io.in_crc.buf = acpi_aml_io.in_buf; 765 acpi_aml_dentry = debugfs_create_file("acpidbg", 766 S_IFREG | S_IRUGO | S_IWUSR, 767 acpi_debugfs_dir, NULL, 768 &acpi_aml_operations); 769 if (acpi_aml_dentry == NULL) { 770 ret = -ENODEV; 771 goto err_exit; 772 } 773 ret = acpi_register_debugger(THIS_MODULE, &acpi_aml_debugger); 774 if (ret) 775 goto err_fs; 776 acpi_aml_initialized = true; 777 778 err_fs: 779 if (ret) { 780 debugfs_remove(acpi_aml_dentry); 781 acpi_aml_dentry = NULL; 782 } 783 err_exit: 784 return ret; 785 } 786 787 void __exit acpi_aml_exit(void) 788 { 789 if (acpi_aml_initialized) { 790 acpi_unregister_debugger(&acpi_aml_debugger); 791 if (acpi_aml_dentry) { 792 debugfs_remove(acpi_aml_dentry); 793 acpi_aml_dentry = NULL; 794 } 795 acpi_aml_initialized = false; 796 } 797 } 798 799 module_init(acpi_aml_init); 800 module_exit(acpi_aml_exit); 801 802 MODULE_AUTHOR("Lv Zheng"); 803 MODULE_DESCRIPTION("ACPI debugger userspace IO driver"); 804 MODULE_LICENSE("GPL"); 805