diff options
author | Glenn Elliott <gelliott@cs.unc.edu> | 2012-03-04 19:47:13 -0500 |
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committer | Glenn Elliott <gelliott@cs.unc.edu> | 2012-03-04 19:47:13 -0500 |
commit | c71c03bda1e86c9d5198c5d83f712e695c4f2a1e (patch) | |
tree | ecb166cb3e2b7e2adb3b5e292245fefd23381ac8 /drivers/acpi/acpica/evglock.c | |
parent | ea53c912f8a86a8567697115b6a0d8152beee5c8 (diff) | |
parent | 6a00f206debf8a5c8899055726ad127dbeeed098 (diff) |
Merge branch 'mpi-master' into wip-k-fmlpwip-k-fmlp
Conflicts:
litmus/sched_cedf.c
Diffstat (limited to 'drivers/acpi/acpica/evglock.c')
-rw-r--r-- | drivers/acpi/acpica/evglock.c | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/evglock.c b/drivers/acpi/acpica/evglock.c new file mode 100644 index 000000000000..56a562a1e5d7 --- /dev/null +++ b/drivers/acpi/acpica/evglock.c | |||
@@ -0,0 +1,335 @@ | |||
1 | /****************************************************************************** | ||
2 | * | ||
3 | * Module Name: evglock - Global Lock support | ||
4 | * | ||
5 | *****************************************************************************/ | ||
6 | |||
7 | /* | ||
8 | * Copyright (C) 2000 - 2011, Intel Corp. | ||
9 | * All rights reserved. | ||
10 | * | ||
11 | * Redistribution and use in source and binary forms, with or without | ||
12 | * modification, are permitted provided that the following conditions | ||
13 | * are met: | ||
14 | * 1. Redistributions of source code must retain the above copyright | ||
15 | * notice, this list of conditions, and the following disclaimer, | ||
16 | * without modification. | ||
17 | * 2. Redistributions in binary form must reproduce at minimum a disclaimer | ||
18 | * substantially similar to the "NO WARRANTY" disclaimer below | ||
19 | * ("Disclaimer") and any redistribution must be conditioned upon | ||
20 | * including a substantially similar Disclaimer requirement for further | ||
21 | * binary redistribution. | ||
22 | * 3. Neither the names of the above-listed copyright holders nor the names | ||
23 | * of any contributors may be used to endorse or promote products derived | ||
24 | * from this software without specific prior written permission. | ||
25 | * | ||
26 | * Alternatively, this software may be distributed under the terms of the | ||
27 | * GNU General Public License ("GPL") version 2 as published by the Free | ||
28 | * Software Foundation. | ||
29 | * | ||
30 | * NO WARRANTY | ||
31 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | ||
32 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | ||
33 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR | ||
34 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | ||
35 | * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | ||
36 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | ||
37 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | ||
38 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | ||
39 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING | ||
40 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | ||
41 | * POSSIBILITY OF SUCH DAMAGES. | ||
42 | */ | ||
43 | |||
44 | #include <acpi/acpi.h> | ||
45 | #include "accommon.h" | ||
46 | #include "acevents.h" | ||
47 | #include "acinterp.h" | ||
48 | |||
49 | #define _COMPONENT ACPI_EVENTS | ||
50 | ACPI_MODULE_NAME("evglock") | ||
51 | |||
52 | /* Local prototypes */ | ||
53 | static u32 acpi_ev_global_lock_handler(void *context); | ||
54 | |||
55 | /******************************************************************************* | ||
56 | * | ||
57 | * FUNCTION: acpi_ev_init_global_lock_handler | ||
58 | * | ||
59 | * PARAMETERS: None | ||
60 | * | ||
61 | * RETURN: Status | ||
62 | * | ||
63 | * DESCRIPTION: Install a handler for the global lock release event | ||
64 | * | ||
65 | ******************************************************************************/ | ||
66 | |||
67 | acpi_status acpi_ev_init_global_lock_handler(void) | ||
68 | { | ||
69 | acpi_status status; | ||
70 | |||
71 | ACPI_FUNCTION_TRACE(ev_init_global_lock_handler); | ||
72 | |||
73 | /* Attempt installation of the global lock handler */ | ||
74 | |||
75 | status = acpi_install_fixed_event_handler(ACPI_EVENT_GLOBAL, | ||
76 | acpi_ev_global_lock_handler, | ||
77 | NULL); | ||
78 | |||
79 | /* | ||
80 | * If the global lock does not exist on this platform, the attempt to | ||
81 | * enable GBL_STATUS will fail (the GBL_ENABLE bit will not stick). | ||
82 | * Map to AE_OK, but mark global lock as not present. Any attempt to | ||
83 | * actually use the global lock will be flagged with an error. | ||
84 | */ | ||
85 | acpi_gbl_global_lock_present = FALSE; | ||
86 | if (status == AE_NO_HARDWARE_RESPONSE) { | ||
87 | ACPI_ERROR((AE_INFO, | ||
88 | "No response from Global Lock hardware, disabling lock")); | ||
89 | |||
90 | return_ACPI_STATUS(AE_OK); | ||
91 | } | ||
92 | |||
93 | status = acpi_os_create_lock(&acpi_gbl_global_lock_pending_lock); | ||
94 | if (ACPI_FAILURE(status)) { | ||
95 | return_ACPI_STATUS(status); | ||
96 | } | ||
97 | |||
98 | acpi_gbl_global_lock_pending = FALSE; | ||
99 | acpi_gbl_global_lock_present = TRUE; | ||
100 | return_ACPI_STATUS(status); | ||
101 | } | ||
102 | |||
103 | /******************************************************************************* | ||
104 | * | ||
105 | * FUNCTION: acpi_ev_remove_global_lock_handler | ||
106 | * | ||
107 | * PARAMETERS: None | ||
108 | * | ||
109 | * RETURN: Status | ||
110 | * | ||
111 | * DESCRIPTION: Remove the handler for the Global Lock | ||
112 | * | ||
113 | ******************************************************************************/ | ||
114 | |||
115 | acpi_status acpi_ev_remove_global_lock_handler(void) | ||
116 | { | ||
117 | acpi_status status; | ||
118 | |||
119 | ACPI_FUNCTION_TRACE(ev_remove_global_lock_handler); | ||
120 | |||
121 | acpi_gbl_global_lock_present = FALSE; | ||
122 | status = acpi_remove_fixed_event_handler(ACPI_EVENT_GLOBAL, | ||
123 | acpi_ev_global_lock_handler); | ||
124 | |||
125 | return_ACPI_STATUS(status); | ||
126 | } | ||
127 | |||
128 | /******************************************************************************* | ||
129 | * | ||
130 | * FUNCTION: acpi_ev_global_lock_handler | ||
131 | * | ||
132 | * PARAMETERS: Context - From thread interface, not used | ||
133 | * | ||
134 | * RETURN: ACPI_INTERRUPT_HANDLED | ||
135 | * | ||
136 | * DESCRIPTION: Invoked directly from the SCI handler when a global lock | ||
137 | * release interrupt occurs. If there is actually a pending | ||
138 | * request for the lock, signal the waiting thread. | ||
139 | * | ||
140 | ******************************************************************************/ | ||
141 | |||
142 | static u32 acpi_ev_global_lock_handler(void *context) | ||
143 | { | ||
144 | acpi_status status; | ||
145 | acpi_cpu_flags flags; | ||
146 | |||
147 | flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock); | ||
148 | |||
149 | /* | ||
150 | * If a request for the global lock is not actually pending, | ||
151 | * we are done. This handles "spurious" global lock interrupts | ||
152 | * which are possible (and have been seen) with bad BIOSs. | ||
153 | */ | ||
154 | if (!acpi_gbl_global_lock_pending) { | ||
155 | goto cleanup_and_exit; | ||
156 | } | ||
157 | |||
158 | /* | ||
159 | * Send a unit to the global lock semaphore. The actual acquisition | ||
160 | * of the global lock will be performed by the waiting thread. | ||
161 | */ | ||
162 | status = acpi_os_signal_semaphore(acpi_gbl_global_lock_semaphore, 1); | ||
163 | if (ACPI_FAILURE(status)) { | ||
164 | ACPI_ERROR((AE_INFO, "Could not signal Global Lock semaphore")); | ||
165 | } | ||
166 | |||
167 | acpi_gbl_global_lock_pending = FALSE; | ||
168 | |||
169 | cleanup_and_exit: | ||
170 | |||
171 | acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags); | ||
172 | return (ACPI_INTERRUPT_HANDLED); | ||
173 | } | ||
174 | |||
175 | /****************************************************************************** | ||
176 | * | ||
177 | * FUNCTION: acpi_ev_acquire_global_lock | ||
178 | * | ||
179 | * PARAMETERS: Timeout - Max time to wait for the lock, in millisec. | ||
180 | * | ||
181 | * RETURN: Status | ||
182 | * | ||
183 | * DESCRIPTION: Attempt to gain ownership of the Global Lock. | ||
184 | * | ||
185 | * MUTEX: Interpreter must be locked | ||
186 | * | ||
187 | * Note: The original implementation allowed multiple threads to "acquire" the | ||
188 | * Global Lock, and the OS would hold the lock until the last thread had | ||
189 | * released it. However, this could potentially starve the BIOS out of the | ||
190 | * lock, especially in the case where there is a tight handshake between the | ||
191 | * Embedded Controller driver and the BIOS. Therefore, this implementation | ||
192 | * allows only one thread to acquire the HW Global Lock at a time, and makes | ||
193 | * the global lock appear as a standard mutex on the OS side. | ||
194 | * | ||
195 | *****************************************************************************/ | ||
196 | |||
197 | acpi_status acpi_ev_acquire_global_lock(u16 timeout) | ||
198 | { | ||
199 | acpi_cpu_flags flags; | ||
200 | acpi_status status; | ||
201 | u8 acquired = FALSE; | ||
202 | |||
203 | ACPI_FUNCTION_TRACE(ev_acquire_global_lock); | ||
204 | |||
205 | /* | ||
206 | * Only one thread can acquire the GL at a time, the global_lock_mutex | ||
207 | * enforces this. This interface releases the interpreter if we must wait. | ||
208 | */ | ||
209 | status = | ||
210 | acpi_ex_system_wait_mutex(acpi_gbl_global_lock_mutex->mutex. | ||
211 | os_mutex, timeout); | ||
212 | if (ACPI_FAILURE(status)) { | ||
213 | return_ACPI_STATUS(status); | ||
214 | } | ||
215 | |||
216 | /* | ||
217 | * Update the global lock handle and check for wraparound. The handle is | ||
218 | * only used for the external global lock interfaces, but it is updated | ||
219 | * here to properly handle the case where a single thread may acquire the | ||
220 | * lock via both the AML and the acpi_acquire_global_lock interfaces. The | ||
221 | * handle is therefore updated on the first acquire from a given thread | ||
222 | * regardless of where the acquisition request originated. | ||
223 | */ | ||
224 | acpi_gbl_global_lock_handle++; | ||
225 | if (acpi_gbl_global_lock_handle == 0) { | ||
226 | acpi_gbl_global_lock_handle = 1; | ||
227 | } | ||
228 | |||
229 | /* | ||
230 | * Make sure that a global lock actually exists. If not, just | ||
231 | * treat the lock as a standard mutex. | ||
232 | */ | ||
233 | if (!acpi_gbl_global_lock_present) { | ||
234 | acpi_gbl_global_lock_acquired = TRUE; | ||
235 | return_ACPI_STATUS(AE_OK); | ||
236 | } | ||
237 | |||
238 | flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock); | ||
239 | |||
240 | do { | ||
241 | |||
242 | /* Attempt to acquire the actual hardware lock */ | ||
243 | |||
244 | ACPI_ACQUIRE_GLOBAL_LOCK(acpi_gbl_FACS, acquired); | ||
245 | if (acquired) { | ||
246 | acpi_gbl_global_lock_acquired = TRUE; | ||
247 | ACPI_DEBUG_PRINT((ACPI_DB_EXEC, | ||
248 | "Acquired hardware Global Lock\n")); | ||
249 | break; | ||
250 | } | ||
251 | |||
252 | /* | ||
253 | * Did not get the lock. The pending bit was set above, and | ||
254 | * we must now wait until we receive the global lock | ||
255 | * released interrupt. | ||
256 | */ | ||
257 | acpi_gbl_global_lock_pending = TRUE; | ||
258 | acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags); | ||
259 | |||
260 | ACPI_DEBUG_PRINT((ACPI_DB_EXEC, | ||
261 | "Waiting for hardware Global Lock\n")); | ||
262 | |||
263 | /* | ||
264 | * Wait for handshake with the global lock interrupt handler. | ||
265 | * This interface releases the interpreter if we must wait. | ||
266 | */ | ||
267 | status = | ||
268 | acpi_ex_system_wait_semaphore | ||
269 | (acpi_gbl_global_lock_semaphore, ACPI_WAIT_FOREVER); | ||
270 | |||
271 | flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock); | ||
272 | |||
273 | } while (ACPI_SUCCESS(status)); | ||
274 | |||
275 | acpi_gbl_global_lock_pending = FALSE; | ||
276 | acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags); | ||
277 | |||
278 | return_ACPI_STATUS(status); | ||
279 | } | ||
280 | |||
281 | /******************************************************************************* | ||
282 | * | ||
283 | * FUNCTION: acpi_ev_release_global_lock | ||
284 | * | ||
285 | * PARAMETERS: None | ||
286 | * | ||
287 | * RETURN: Status | ||
288 | * | ||
289 | * DESCRIPTION: Releases ownership of the Global Lock. | ||
290 | * | ||
291 | ******************************************************************************/ | ||
292 | |||
293 | acpi_status acpi_ev_release_global_lock(void) | ||
294 | { | ||
295 | u8 pending = FALSE; | ||
296 | acpi_status status = AE_OK; | ||
297 | |||
298 | ACPI_FUNCTION_TRACE(ev_release_global_lock); | ||
299 | |||
300 | /* Lock must be already acquired */ | ||
301 | |||
302 | if (!acpi_gbl_global_lock_acquired) { | ||
303 | ACPI_WARNING((AE_INFO, | ||
304 | "Cannot release the ACPI Global Lock, it has not been acquired")); | ||
305 | return_ACPI_STATUS(AE_NOT_ACQUIRED); | ||
306 | } | ||
307 | |||
308 | if (acpi_gbl_global_lock_present) { | ||
309 | |||
310 | /* Allow any thread to release the lock */ | ||
311 | |||
312 | ACPI_RELEASE_GLOBAL_LOCK(acpi_gbl_FACS, pending); | ||
313 | |||
314 | /* | ||
315 | * If the pending bit was set, we must write GBL_RLS to the control | ||
316 | * register | ||
317 | */ | ||
318 | if (pending) { | ||
319 | status = | ||
320 | acpi_write_bit_register | ||
321 | (ACPI_BITREG_GLOBAL_LOCK_RELEASE, | ||
322 | ACPI_ENABLE_EVENT); | ||
323 | } | ||
324 | |||
325 | ACPI_DEBUG_PRINT((ACPI_DB_EXEC, | ||
326 | "Released hardware Global Lock\n")); | ||
327 | } | ||
328 | |||
329 | acpi_gbl_global_lock_acquired = FALSE; | ||
330 | |||
331 | /* Release the local GL mutex */ | ||
332 | |||
333 | acpi_os_release_mutex(acpi_gbl_global_lock_mutex->mutex.os_mutex); | ||
334 | return_ACPI_STATUS(status); | ||
335 | } | ||