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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
8cfb0cdf LZ |
2 | /* |
3 | * ACPI AML interfacing support | |
4 | * | |
5 | * Copyright (C) 2015, Intel Corporation | |
6 | * Authors: Lv Zheng <lv.zheng@intel.com> | |
8cfb0cdf LZ |
7 | */ |
8 | ||
9 | /* #define DEBUG */ | |
b6aeab44 | 10 | #define pr_fmt(fmt) "ACPI: AML: " fmt |
8cfb0cdf LZ |
11 | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/wait.h> | |
15 | #include <linux/poll.h> | |
16 | #include <linux/sched.h> | |
17 | #include <linux/kthread.h> | |
18 | #include <linux/proc_fs.h> | |
19 | #include <linux/debugfs.h> | |
20 | #include <linux/circ_buf.h> | |
836d0830 | 21 | #include <linux/acpi.h> |
8cfb0cdf LZ |
22 | #include "internal.h" |
23 | ||
24 | #define ACPI_AML_BUF_ALIGN (sizeof (acpi_size)) | |
25 | #define ACPI_AML_BUF_SIZE PAGE_SIZE | |
26 | ||
27 | #define circ_count(circ) \ | |
28 | (CIRC_CNT((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE)) | |
29 | #define circ_count_to_end(circ) \ | |
30 | (CIRC_CNT_TO_END((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE)) | |
31 | #define circ_space(circ) \ | |
32 | (CIRC_SPACE((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE)) | |
33 | #define circ_space_to_end(circ) \ | |
34 | (CIRC_SPACE_TO_END((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE)) | |
35 | ||
36 | #define ACPI_AML_OPENED 0x0001 | |
37 | #define ACPI_AML_CLOSED 0x0002 | |
38 | #define ACPI_AML_IN_USER 0x0004 /* user space is writing cmd */ | |
39 | #define ACPI_AML_IN_KERN 0x0008 /* kernel space is reading cmd */ | |
40 | #define ACPI_AML_OUT_USER 0x0010 /* user space is reading log */ | |
41 | #define ACPI_AML_OUT_KERN 0x0020 /* kernel space is writing log */ | |
42 | #define ACPI_AML_USER (ACPI_AML_IN_USER | ACPI_AML_OUT_USER) | |
43 | #define ACPI_AML_KERN (ACPI_AML_IN_KERN | ACPI_AML_OUT_KERN) | |
44 | #define ACPI_AML_BUSY (ACPI_AML_USER | ACPI_AML_KERN) | |
45 | #define ACPI_AML_OPEN (ACPI_AML_OPENED | ACPI_AML_CLOSED) | |
46 | ||
47 | struct acpi_aml_io { | |
48 | wait_queue_head_t wait; | |
49 | unsigned long flags; | |
50 | unsigned long users; | |
51 | struct mutex lock; | |
52 | struct task_struct *thread; | |
53 | char out_buf[ACPI_AML_BUF_SIZE] __aligned(ACPI_AML_BUF_ALIGN); | |
54 | struct circ_buf out_crc; | |
55 | char in_buf[ACPI_AML_BUF_SIZE] __aligned(ACPI_AML_BUF_ALIGN); | |
56 | struct circ_buf in_crc; | |
57 | acpi_osd_exec_callback function; | |
58 | void *context; | |
59 | unsigned long usages; | |
60 | }; | |
61 | ||
62 | static struct acpi_aml_io acpi_aml_io; | |
63 | static bool acpi_aml_initialized; | |
64 | static struct file *acpi_aml_active_reader; | |
65 | static struct dentry *acpi_aml_dentry; | |
66 | ||
67 | static inline bool __acpi_aml_running(void) | |
68 | { | |
69 | return acpi_aml_io.thread ? true : false; | |
70 | } | |
71 | ||
72 | static inline bool __acpi_aml_access_ok(unsigned long flag) | |
73 | { | |
74 | /* | |
75 | * The debugger interface is in opened state (OPENED && !CLOSED), | |
76 | * then it is allowed to access the debugger buffers from either | |
77 | * user space or the kernel space. | |
78 | * In addition, for the kernel space, only the debugger thread | |
79 | * (thread ID matched) is allowed to access. | |
80 | */ | |
81 | if (!(acpi_aml_io.flags & ACPI_AML_OPENED) || | |
82 | (acpi_aml_io.flags & ACPI_AML_CLOSED) || | |
83 | !__acpi_aml_running()) | |
84 | return false; | |
85 | if ((flag & ACPI_AML_KERN) && | |
86 | current != acpi_aml_io.thread) | |
87 | return false; | |
88 | return true; | |
89 | } | |
90 | ||
91 | static inline bool __acpi_aml_readable(struct circ_buf *circ, unsigned long flag) | |
92 | { | |
93 | /* | |
94 | * Another read is not in progress and there is data in buffer | |
95 | * available for read. | |
96 | */ | |
97 | if (!(acpi_aml_io.flags & flag) && circ_count(circ)) | |
98 | return true; | |
99 | return false; | |
100 | } | |
101 | ||
102 | static inline bool __acpi_aml_writable(struct circ_buf *circ, unsigned long flag) | |
103 | { | |
104 | /* | |
105 | * Another write is not in progress and there is buffer space | |
106 | * available for write. | |
107 | */ | |
108 | if (!(acpi_aml_io.flags & flag) && circ_space(circ)) | |
109 | return true; | |
110 | return false; | |
111 | } | |
112 | ||
113 | static inline bool __acpi_aml_busy(void) | |
114 | { | |
115 | if (acpi_aml_io.flags & ACPI_AML_BUSY) | |
116 | return true; | |
117 | return false; | |
118 | } | |
119 | ||
120 | static inline bool __acpi_aml_opened(void) | |
121 | { | |
122 | if (acpi_aml_io.flags & ACPI_AML_OPEN) | |
123 | return true; | |
124 | return false; | |
125 | } | |
126 | ||
127 | static inline bool __acpi_aml_used(void) | |
128 | { | |
129 | return acpi_aml_io.usages ? true : false; | |
130 | } | |
131 | ||
132 | static inline bool acpi_aml_running(void) | |
133 | { | |
134 | bool ret; | |
135 | ||
136 | mutex_lock(&acpi_aml_io.lock); | |
137 | ret = __acpi_aml_running(); | |
138 | mutex_unlock(&acpi_aml_io.lock); | |
139 | return ret; | |
140 | } | |
141 | ||
142 | static bool acpi_aml_busy(void) | |
143 | { | |
144 | bool ret; | |
145 | ||
146 | mutex_lock(&acpi_aml_io.lock); | |
147 | ret = __acpi_aml_busy(); | |
148 | mutex_unlock(&acpi_aml_io.lock); | |
149 | return ret; | |
150 | } | |
151 | ||
152 | static bool acpi_aml_used(void) | |
153 | { | |
154 | bool ret; | |
155 | ||
156 | /* | |
157 | * The usage count is prepared to avoid race conditions between the | |
158 | * starts and the stops of the debugger thread. | |
159 | */ | |
160 | mutex_lock(&acpi_aml_io.lock); | |
161 | ret = __acpi_aml_used(); | |
162 | mutex_unlock(&acpi_aml_io.lock); | |
163 | return ret; | |
164 | } | |
165 | ||
166 | static bool acpi_aml_kern_readable(void) | |
167 | { | |
168 | bool ret; | |
169 | ||
170 | mutex_lock(&acpi_aml_io.lock); | |
171 | ret = !__acpi_aml_access_ok(ACPI_AML_IN_KERN) || | |
172 | __acpi_aml_readable(&acpi_aml_io.in_crc, ACPI_AML_IN_KERN); | |
173 | mutex_unlock(&acpi_aml_io.lock); | |
174 | return ret; | |
175 | } | |
176 | ||
177 | static bool acpi_aml_kern_writable(void) | |
178 | { | |
179 | bool ret; | |
180 | ||
181 | mutex_lock(&acpi_aml_io.lock); | |
182 | ret = !__acpi_aml_access_ok(ACPI_AML_OUT_KERN) || | |
183 | __acpi_aml_writable(&acpi_aml_io.out_crc, ACPI_AML_OUT_KERN); | |
184 | mutex_unlock(&acpi_aml_io.lock); | |
185 | return ret; | |
186 | } | |
187 | ||
188 | static bool acpi_aml_user_readable(void) | |
189 | { | |
190 | bool ret; | |
191 | ||
192 | mutex_lock(&acpi_aml_io.lock); | |
193 | ret = !__acpi_aml_access_ok(ACPI_AML_OUT_USER) || | |
194 | __acpi_aml_readable(&acpi_aml_io.out_crc, ACPI_AML_OUT_USER); | |
195 | mutex_unlock(&acpi_aml_io.lock); | |
196 | return ret; | |
197 | } | |
198 | ||
199 | static bool acpi_aml_user_writable(void) | |
200 | { | |
201 | bool ret; | |
202 | ||
203 | mutex_lock(&acpi_aml_io.lock); | |
204 | ret = !__acpi_aml_access_ok(ACPI_AML_IN_USER) || | |
205 | __acpi_aml_writable(&acpi_aml_io.in_crc, ACPI_AML_IN_USER); | |
206 | mutex_unlock(&acpi_aml_io.lock); | |
207 | return ret; | |
208 | } | |
209 | ||
210 | static int acpi_aml_lock_write(struct circ_buf *circ, unsigned long flag) | |
211 | { | |
212 | int ret = 0; | |
213 | ||
214 | mutex_lock(&acpi_aml_io.lock); | |
215 | if (!__acpi_aml_access_ok(flag)) { | |
216 | ret = -EFAULT; | |
217 | goto out; | |
218 | } | |
219 | if (!__acpi_aml_writable(circ, flag)) { | |
220 | ret = -EAGAIN; | |
221 | goto out; | |
222 | } | |
223 | acpi_aml_io.flags |= flag; | |
224 | out: | |
225 | mutex_unlock(&acpi_aml_io.lock); | |
226 | return ret; | |
227 | } | |
228 | ||
229 | static int acpi_aml_lock_read(struct circ_buf *circ, unsigned long flag) | |
230 | { | |
231 | int ret = 0; | |
232 | ||
233 | mutex_lock(&acpi_aml_io.lock); | |
234 | if (!__acpi_aml_access_ok(flag)) { | |
235 | ret = -EFAULT; | |
236 | goto out; | |
237 | } | |
238 | if (!__acpi_aml_readable(circ, flag)) { | |
239 | ret = -EAGAIN; | |
240 | goto out; | |
241 | } | |
242 | acpi_aml_io.flags |= flag; | |
243 | out: | |
244 | mutex_unlock(&acpi_aml_io.lock); | |
245 | return ret; | |
246 | } | |
247 | ||
248 | static void acpi_aml_unlock_fifo(unsigned long flag, bool wakeup) | |
249 | { | |
250 | mutex_lock(&acpi_aml_io.lock); | |
251 | acpi_aml_io.flags &= ~flag; | |
252 | if (wakeup) | |
253 | wake_up_interruptible(&acpi_aml_io.wait); | |
254 | mutex_unlock(&acpi_aml_io.lock); | |
255 | } | |
256 | ||
257 | static int acpi_aml_write_kern(const char *buf, int len) | |
258 | { | |
259 | int ret; | |
260 | struct circ_buf *crc = &acpi_aml_io.out_crc; | |
261 | int n; | |
262 | char *p; | |
263 | ||
264 | ret = acpi_aml_lock_write(crc, ACPI_AML_OUT_KERN); | |
287980e4 | 265 | if (ret < 0) |
8cfb0cdf LZ |
266 | return ret; |
267 | /* sync tail before inserting logs */ | |
268 | smp_mb(); | |
269 | p = &crc->buf[crc->head]; | |
270 | n = min(len, circ_space_to_end(crc)); | |
271 | memcpy(p, buf, n); | |
272 | /* sync head after inserting logs */ | |
273 | smp_wmb(); | |
274 | crc->head = (crc->head + n) & (ACPI_AML_BUF_SIZE - 1); | |
275 | acpi_aml_unlock_fifo(ACPI_AML_OUT_KERN, true); | |
276 | return n; | |
277 | } | |
278 | ||
279 | static int acpi_aml_readb_kern(void) | |
280 | { | |
281 | int ret; | |
282 | struct circ_buf *crc = &acpi_aml_io.in_crc; | |
283 | char *p; | |
284 | ||
285 | ret = acpi_aml_lock_read(crc, ACPI_AML_IN_KERN); | |
287980e4 | 286 | if (ret < 0) |
8cfb0cdf LZ |
287 | return ret; |
288 | /* sync head before removing cmds */ | |
289 | smp_rmb(); | |
290 | p = &crc->buf[crc->tail]; | |
291 | ret = (int)*p; | |
292 | /* sync tail before inserting cmds */ | |
293 | smp_mb(); | |
294 | crc->tail = (crc->tail + 1) & (ACPI_AML_BUF_SIZE - 1); | |
295 | acpi_aml_unlock_fifo(ACPI_AML_IN_KERN, true); | |
296 | return ret; | |
297 | } | |
298 | ||
299 | /* | |
300 | * acpi_aml_write_log() - Capture debugger output | |
301 | * @msg: the debugger output | |
302 | * | |
303 | * This function should be used to implement acpi_os_printf() to filter out | |
304 | * the debugger output and store the output into the debugger interface | |
305 | * buffer. Return the size of stored logs or errno. | |
306 | */ | |
836d0830 | 307 | static ssize_t acpi_aml_write_log(const char *msg) |
8cfb0cdf LZ |
308 | { |
309 | int ret = 0; | |
310 | int count = 0, size = 0; | |
311 | ||
312 | if (!acpi_aml_initialized) | |
313 | return -ENODEV; | |
314 | if (msg) | |
315 | count = strlen(msg); | |
316 | while (count > 0) { | |
317 | again: | |
318 | ret = acpi_aml_write_kern(msg + size, count); | |
319 | if (ret == -EAGAIN) { | |
320 | ret = wait_event_interruptible(acpi_aml_io.wait, | |
321 | acpi_aml_kern_writable()); | |
322 | /* | |
323 | * We need to retry when the condition | |
324 | * becomes true. | |
325 | */ | |
326 | if (ret == 0) | |
327 | goto again; | |
328 | break; | |
329 | } | |
287980e4 | 330 | if (ret < 0) |
8cfb0cdf LZ |
331 | break; |
332 | size += ret; | |
333 | count -= ret; | |
334 | } | |
335 | return size > 0 ? size : ret; | |
336 | } | |
8cfb0cdf LZ |
337 | |
338 | /* | |
339 | * acpi_aml_read_cmd() - Capture debugger input | |
340 | * @msg: the debugger input | |
341 | * @size: the size of the debugger input | |
342 | * | |
343 | * This function should be used to implement acpi_os_get_line() to capture | |
344 | * the debugger input commands and store the input commands into the | |
345 | * debugger interface buffer. Return the size of stored commands or errno. | |
346 | */ | |
836d0830 | 347 | static ssize_t acpi_aml_read_cmd(char *msg, size_t count) |
8cfb0cdf LZ |
348 | { |
349 | int ret = 0; | |
350 | int size = 0; | |
351 | ||
352 | /* | |
353 | * This is ensured by the running fact of the debugger thread | |
354 | * unless a bug is introduced. | |
355 | */ | |
356 | BUG_ON(!acpi_aml_initialized); | |
357 | while (count > 0) { | |
358 | again: | |
359 | /* | |
360 | * Check each input byte to find the end of the command. | |
361 | */ | |
362 | ret = acpi_aml_readb_kern(); | |
363 | if (ret == -EAGAIN) { | |
364 | ret = wait_event_interruptible(acpi_aml_io.wait, | |
365 | acpi_aml_kern_readable()); | |
366 | /* | |
367 | * We need to retry when the condition becomes | |
368 | * true. | |
369 | */ | |
370 | if (ret == 0) | |
371 | goto again; | |
372 | } | |
287980e4 | 373 | if (ret < 0) |
8cfb0cdf LZ |
374 | break; |
375 | *(msg + size) = (char)ret; | |
376 | size++; | |
377 | count--; | |
378 | if (ret == '\n') { | |
379 | /* | |
380 | * acpi_os_get_line() requires a zero terminated command | |
381 | * string. | |
382 | */ | |
383 | *(msg + size - 1) = '\0'; | |
384 | break; | |
385 | } | |
386 | } | |
387 | return size > 0 ? size : ret; | |
388 | } | |
8cfb0cdf | 389 | |
603fadf3 | 390 | static int acpi_aml_thread(void *unused) |
8cfb0cdf LZ |
391 | { |
392 | acpi_osd_exec_callback function = NULL; | |
393 | void *context; | |
394 | ||
395 | mutex_lock(&acpi_aml_io.lock); | |
396 | if (acpi_aml_io.function) { | |
397 | acpi_aml_io.usages++; | |
398 | function = acpi_aml_io.function; | |
399 | context = acpi_aml_io.context; | |
400 | } | |
401 | mutex_unlock(&acpi_aml_io.lock); | |
402 | ||
403 | if (function) | |
404 | function(context); | |
405 | ||
406 | mutex_lock(&acpi_aml_io.lock); | |
407 | acpi_aml_io.usages--; | |
408 | if (!__acpi_aml_used()) { | |
409 | acpi_aml_io.thread = NULL; | |
410 | wake_up(&acpi_aml_io.wait); | |
411 | } | |
412 | mutex_unlock(&acpi_aml_io.lock); | |
413 | ||
414 | return 0; | |
415 | } | |
416 | ||
417 | /* | |
418 | * acpi_aml_create_thread() - Create AML debugger thread | |
419 | * @function: the debugger thread callback | |
420 | * @context: the context to be passed to the debugger thread | |
421 | * | |
422 | * This function should be used to implement acpi_os_execute() which is | |
423 | * used by the ACPICA debugger to create the debugger thread. | |
424 | */ | |
836d0830 | 425 | static int acpi_aml_create_thread(acpi_osd_exec_callback function, void *context) |
8cfb0cdf LZ |
426 | { |
427 | struct task_struct *t; | |
428 | ||
429 | mutex_lock(&acpi_aml_io.lock); | |
430 | acpi_aml_io.function = function; | |
431 | acpi_aml_io.context = context; | |
432 | mutex_unlock(&acpi_aml_io.lock); | |
433 | ||
434 | t = kthread_create(acpi_aml_thread, NULL, "aml"); | |
435 | if (IS_ERR(t)) { | |
436 | pr_err("Failed to create AML debugger thread.\n"); | |
437 | return PTR_ERR(t); | |
438 | } | |
439 | ||
440 | mutex_lock(&acpi_aml_io.lock); | |
441 | acpi_aml_io.thread = t; | |
442 | acpi_set_debugger_thread_id((acpi_thread_id)(unsigned long)t); | |
443 | wake_up_process(t); | |
444 | mutex_unlock(&acpi_aml_io.lock); | |
445 | return 0; | |
446 | } | |
8cfb0cdf | 447 | |
836d0830 LZ |
448 | static int acpi_aml_wait_command_ready(bool single_step, |
449 | char *buffer, size_t length) | |
8cfb0cdf LZ |
450 | { |
451 | acpi_status status; | |
452 | ||
836d0830 | 453 | if (single_step) |
8cfb0cdf | 454 | acpi_os_printf("\n%1c ", ACPI_DEBUGGER_EXECUTE_PROMPT); |
836d0830 LZ |
455 | else |
456 | acpi_os_printf("\n%1c ", ACPI_DEBUGGER_COMMAND_PROMPT); | |
8cfb0cdf | 457 | |
836d0830 | 458 | status = acpi_os_get_line(buffer, length, NULL); |
8cfb0cdf LZ |
459 | if (ACPI_FAILURE(status)) |
460 | return -EINVAL; | |
461 | return 0; | |
462 | } | |
8cfb0cdf | 463 | |
836d0830 | 464 | static int acpi_aml_notify_command_complete(void) |
8cfb0cdf LZ |
465 | { |
466 | return 0; | |
467 | } | |
8cfb0cdf LZ |
468 | |
469 | static int acpi_aml_open(struct inode *inode, struct file *file) | |
470 | { | |
471 | int ret = 0; | |
472 | acpi_status status; | |
473 | ||
474 | mutex_lock(&acpi_aml_io.lock); | |
475 | /* | |
476 | * The debugger interface is being closed, no new user is allowed | |
477 | * during this period. | |
478 | */ | |
479 | if (acpi_aml_io.flags & ACPI_AML_CLOSED) { | |
480 | ret = -EBUSY; | |
481 | goto err_lock; | |
482 | } | |
483 | if ((file->f_flags & O_ACCMODE) != O_WRONLY) { | |
484 | /* | |
485 | * Only one reader is allowed to initiate the debugger | |
486 | * thread. | |
487 | */ | |
488 | if (acpi_aml_active_reader) { | |
489 | ret = -EBUSY; | |
490 | goto err_lock; | |
491 | } else { | |
492 | pr_debug("Opening debugger reader.\n"); | |
493 | acpi_aml_active_reader = file; | |
494 | } | |
495 | } else { | |
496 | /* | |
497 | * No writer is allowed unless the debugger thread is | |
498 | * ready. | |
499 | */ | |
500 | if (!(acpi_aml_io.flags & ACPI_AML_OPENED)) { | |
501 | ret = -ENODEV; | |
502 | goto err_lock; | |
503 | } | |
504 | } | |
505 | if (acpi_aml_active_reader == file) { | |
506 | pr_debug("Opening debugger interface.\n"); | |
507 | mutex_unlock(&acpi_aml_io.lock); | |
508 | ||
509 | pr_debug("Initializing debugger thread.\n"); | |
510 | status = acpi_initialize_debugger(); | |
511 | if (ACPI_FAILURE(status)) { | |
512 | pr_err("Failed to initialize debugger.\n"); | |
513 | ret = -EINVAL; | |
59adb398 | 514 | goto err_exit; |
8cfb0cdf | 515 | } |
8cfb0cdf LZ |
516 | pr_debug("Debugger thread initialized.\n"); |
517 | ||
518 | mutex_lock(&acpi_aml_io.lock); | |
73af2d59 | 519 | acpi_aml_io.flags |= ACPI_AML_OPENED; |
8cfb0cdf LZ |
520 | acpi_aml_io.out_crc.head = acpi_aml_io.out_crc.tail = 0; |
521 | acpi_aml_io.in_crc.head = acpi_aml_io.in_crc.tail = 0; | |
522 | pr_debug("Debugger interface opened.\n"); | |
523 | } | |
524 | acpi_aml_io.users++; | |
525 | err_lock: | |
287980e4 | 526 | if (ret < 0) { |
8cfb0cdf LZ |
527 | if (acpi_aml_active_reader == file) |
528 | acpi_aml_active_reader = NULL; | |
529 | } | |
530 | mutex_unlock(&acpi_aml_io.lock); | |
59adb398 | 531 | err_exit: |
8cfb0cdf LZ |
532 | return ret; |
533 | } | |
534 | ||
535 | static int acpi_aml_release(struct inode *inode, struct file *file) | |
536 | { | |
537 | mutex_lock(&acpi_aml_io.lock); | |
538 | acpi_aml_io.users--; | |
539 | if (file == acpi_aml_active_reader) { | |
540 | pr_debug("Closing debugger reader.\n"); | |
541 | acpi_aml_active_reader = NULL; | |
542 | ||
543 | pr_debug("Closing debugger interface.\n"); | |
544 | acpi_aml_io.flags |= ACPI_AML_CLOSED; | |
545 | ||
546 | /* | |
547 | * Wake up all user space/kernel space blocked | |
548 | * readers/writers. | |
549 | */ | |
550 | wake_up_interruptible(&acpi_aml_io.wait); | |
551 | mutex_unlock(&acpi_aml_io.lock); | |
552 | /* | |
553 | * Wait all user space/kernel space readers/writers to | |
554 | * stop so that ACPICA command loop of the debugger thread | |
555 | * should fail all its command line reads after this point. | |
556 | */ | |
557 | wait_event(acpi_aml_io.wait, !acpi_aml_busy()); | |
558 | ||
559 | /* | |
560 | * Then we try to terminate the debugger thread if it is | |
561 | * not terminated. | |
562 | */ | |
563 | pr_debug("Terminating debugger thread.\n"); | |
564 | acpi_terminate_debugger(); | |
565 | wait_event(acpi_aml_io.wait, !acpi_aml_used()); | |
566 | pr_debug("Debugger thread terminated.\n"); | |
567 | ||
568 | mutex_lock(&acpi_aml_io.lock); | |
569 | acpi_aml_io.flags &= ~ACPI_AML_OPENED; | |
570 | } | |
571 | if (acpi_aml_io.users == 0) { | |
572 | pr_debug("Debugger interface closed.\n"); | |
573 | acpi_aml_io.flags &= ~ACPI_AML_CLOSED; | |
574 | } | |
575 | mutex_unlock(&acpi_aml_io.lock); | |
576 | return 0; | |
577 | } | |
578 | ||
579 | static int acpi_aml_read_user(char __user *buf, int len) | |
580 | { | |
581 | int ret; | |
582 | struct circ_buf *crc = &acpi_aml_io.out_crc; | |
583 | int n; | |
584 | char *p; | |
585 | ||
586 | ret = acpi_aml_lock_read(crc, ACPI_AML_OUT_USER); | |
287980e4 | 587 | if (ret < 0) |
8cfb0cdf LZ |
588 | return ret; |
589 | /* sync head before removing logs */ | |
590 | smp_rmb(); | |
591 | p = &crc->buf[crc->tail]; | |
592 | n = min(len, circ_count_to_end(crc)); | |
ec74765d DC |
593 | if (copy_to_user(buf, p, n)) { |
594 | ret = -EFAULT; | |
8cfb0cdf | 595 | goto out; |
ec74765d | 596 | } |
8cfb0cdf LZ |
597 | /* sync tail after removing logs */ |
598 | smp_mb(); | |
599 | crc->tail = (crc->tail + n) & (ACPI_AML_BUF_SIZE - 1); | |
600 | ret = n; | |
601 | out: | |
7e3fd813 | 602 | acpi_aml_unlock_fifo(ACPI_AML_OUT_USER, ret >= 0); |
8cfb0cdf LZ |
603 | return ret; |
604 | } | |
605 | ||
606 | static ssize_t acpi_aml_read(struct file *file, char __user *buf, | |
607 | size_t count, loff_t *ppos) | |
608 | { | |
609 | int ret = 0; | |
610 | int size = 0; | |
611 | ||
8cfb0cdf LZ |
612 | if (!count) |
613 | return 0; | |
96d4f267 | 614 | if (!access_ok(buf, count)) |
8cfb0cdf LZ |
615 | return -EFAULT; |
616 | ||
617 | while (count > 0) { | |
618 | again: | |
619 | ret = acpi_aml_read_user(buf + size, count); | |
620 | if (ret == -EAGAIN) { | |
621 | if (file->f_flags & O_NONBLOCK) | |
622 | break; | |
623 | else { | |
624 | ret = wait_event_interruptible(acpi_aml_io.wait, | |
625 | acpi_aml_user_readable()); | |
626 | /* | |
627 | * We need to retry when the condition | |
628 | * becomes true. | |
629 | */ | |
630 | if (ret == 0) | |
631 | goto again; | |
632 | } | |
633 | } | |
287980e4 | 634 | if (ret < 0) { |
8cfb0cdf LZ |
635 | if (!acpi_aml_running()) |
636 | ret = 0; | |
637 | break; | |
638 | } | |
639 | if (ret) { | |
640 | size += ret; | |
641 | count -= ret; | |
642 | *ppos += ret; | |
643 | break; | |
644 | } | |
645 | } | |
646 | return size > 0 ? size : ret; | |
647 | } | |
648 | ||
649 | static int acpi_aml_write_user(const char __user *buf, int len) | |
650 | { | |
651 | int ret; | |
652 | struct circ_buf *crc = &acpi_aml_io.in_crc; | |
653 | int n; | |
654 | char *p; | |
655 | ||
656 | ret = acpi_aml_lock_write(crc, ACPI_AML_IN_USER); | |
287980e4 | 657 | if (ret < 0) |
8cfb0cdf LZ |
658 | return ret; |
659 | /* sync tail before inserting cmds */ | |
660 | smp_mb(); | |
661 | p = &crc->buf[crc->head]; | |
662 | n = min(len, circ_space_to_end(crc)); | |
ec74765d DC |
663 | if (copy_from_user(p, buf, n)) { |
664 | ret = -EFAULT; | |
8cfb0cdf | 665 | goto out; |
ec74765d | 666 | } |
8cfb0cdf LZ |
667 | /* sync head after inserting cmds */ |
668 | smp_wmb(); | |
669 | crc->head = (crc->head + n) & (ACPI_AML_BUF_SIZE - 1); | |
670 | ret = n; | |
671 | out: | |
7e3fd813 | 672 | acpi_aml_unlock_fifo(ACPI_AML_IN_USER, ret >= 0); |
8cfb0cdf LZ |
673 | return n; |
674 | } | |
675 | ||
676 | static ssize_t acpi_aml_write(struct file *file, const char __user *buf, | |
677 | size_t count, loff_t *ppos) | |
678 | { | |
679 | int ret = 0; | |
680 | int size = 0; | |
681 | ||
8cfb0cdf LZ |
682 | if (!count) |
683 | return 0; | |
96d4f267 | 684 | if (!access_ok(buf, count)) |
8cfb0cdf LZ |
685 | return -EFAULT; |
686 | ||
687 | while (count > 0) { | |
688 | again: | |
689 | ret = acpi_aml_write_user(buf + size, count); | |
690 | if (ret == -EAGAIN) { | |
691 | if (file->f_flags & O_NONBLOCK) | |
692 | break; | |
693 | else { | |
694 | ret = wait_event_interruptible(acpi_aml_io.wait, | |
695 | acpi_aml_user_writable()); | |
696 | /* | |
697 | * We need to retry when the condition | |
698 | * becomes true. | |
699 | */ | |
700 | if (ret == 0) | |
701 | goto again; | |
702 | } | |
703 | } | |
287980e4 | 704 | if (ret < 0) { |
8cfb0cdf LZ |
705 | if (!acpi_aml_running()) |
706 | ret = 0; | |
707 | break; | |
708 | } | |
709 | if (ret) { | |
710 | size += ret; | |
711 | count -= ret; | |
712 | *ppos += ret; | |
713 | } | |
714 | } | |
715 | return size > 0 ? size : ret; | |
716 | } | |
717 | ||
0d9b87f3 | 718 | static __poll_t acpi_aml_poll(struct file *file, poll_table *wait) |
8cfb0cdf | 719 | { |
0d9b87f3 | 720 | __poll_t masks = 0; |
8cfb0cdf LZ |
721 | |
722 | poll_wait(file, &acpi_aml_io.wait, wait); | |
723 | if (acpi_aml_user_readable()) | |
a9a08845 | 724 | masks |= EPOLLIN | EPOLLRDNORM; |
8cfb0cdf | 725 | if (acpi_aml_user_writable()) |
a9a08845 | 726 | masks |= EPOLLOUT | EPOLLWRNORM; |
8cfb0cdf LZ |
727 | |
728 | return masks; | |
729 | } | |
730 | ||
731 | static const struct file_operations acpi_aml_operations = { | |
732 | .read = acpi_aml_read, | |
733 | .write = acpi_aml_write, | |
734 | .poll = acpi_aml_poll, | |
735 | .open = acpi_aml_open, | |
736 | .release = acpi_aml_release, | |
737 | .llseek = generic_file_llseek, | |
738 | }; | |
739 | ||
836d0830 LZ |
740 | static const struct acpi_debugger_ops acpi_aml_debugger = { |
741 | .create_thread = acpi_aml_create_thread, | |
742 | .read_cmd = acpi_aml_read_cmd, | |
743 | .write_log = acpi_aml_write_log, | |
744 | .wait_command_ready = acpi_aml_wait_command_ready, | |
745 | .notify_command_complete = acpi_aml_notify_command_complete, | |
746 | }; | |
747 | ||
8cfb0cdf LZ |
748 | int __init acpi_aml_init(void) |
749 | { | |
6010ce3f | 750 | int ret; |
836d0830 | 751 | |
8cfb0cdf LZ |
752 | /* Initialize AML IO interface */ |
753 | mutex_init(&acpi_aml_io.lock); | |
754 | init_waitqueue_head(&acpi_aml_io.wait); | |
755 | acpi_aml_io.out_crc.buf = acpi_aml_io.out_buf; | |
756 | acpi_aml_io.in_crc.buf = acpi_aml_io.in_buf; | |
6010ce3f | 757 | |
8cfb0cdf LZ |
758 | acpi_aml_dentry = debugfs_create_file("acpidbg", |
759 | S_IFREG | S_IRUGO | S_IWUSR, | |
760 | acpi_debugfs_dir, NULL, | |
761 | &acpi_aml_operations); | |
836d0830 | 762 | |
6010ce3f | 763 | ret = acpi_register_debugger(THIS_MODULE, &acpi_aml_debugger); |
836d0830 LZ |
764 | if (ret) { |
765 | debugfs_remove(acpi_aml_dentry); | |
766 | acpi_aml_dentry = NULL; | |
6010ce3f | 767 | return ret; |
836d0830 | 768 | } |
6010ce3f RW |
769 | |
770 | acpi_aml_initialized = true; | |
771 | return 0; | |
8cfb0cdf LZ |
772 | } |
773 | ||
8cfb0cdf LZ |
774 | void __exit acpi_aml_exit(void) |
775 | { | |
836d0830 LZ |
776 | if (acpi_aml_initialized) { |
777 | acpi_unregister_debugger(&acpi_aml_debugger); | |
9ec6dbfb GKH |
778 | debugfs_remove(acpi_aml_dentry); |
779 | acpi_aml_dentry = NULL; | |
836d0830 LZ |
780 | acpi_aml_initialized = false; |
781 | } | |
8cfb0cdf LZ |
782 | } |
783 | ||
784 | module_init(acpi_aml_init); | |
785 | module_exit(acpi_aml_exit); | |
836d0830 LZ |
786 | |
787 | MODULE_AUTHOR("Lv Zheng"); | |
788 | MODULE_DESCRIPTION("ACPI debugger userspace IO driver"); | |
789 | MODULE_LICENSE("GPL"); |