evglock.c revision 228110
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 <contrib/dev/acpica/include/acpi.h> 45#include <contrib/dev/acpica/include/accommon.h> 46#include <contrib/dev/acpica/include/acevents.h> 47#include <contrib/dev/acpica/include/acinterp.h> 48 49#define _COMPONENT ACPI_EVENTS 50 ACPI_MODULE_NAME ("evglock") 51 52 53/* Local prototypes */ 54 55static UINT32 56AcpiEvGlobalLockHandler ( 57 void *Context); 58 59 60/******************************************************************************* 61 * 62 * FUNCTION: AcpiEvInitGlobalLockHandler 63 * 64 * PARAMETERS: None 65 * 66 * RETURN: Status 67 * 68 * DESCRIPTION: Install a handler for the global lock release event 69 * 70 ******************************************************************************/ 71 72ACPI_STATUS 73AcpiEvInitGlobalLockHandler ( 74 void) 75{ 76 ACPI_STATUS Status; 77 78 79 ACPI_FUNCTION_TRACE (EvInitGlobalLockHandler); 80 81 82 /* If Hardware Reduced flag is set, there is no global lock */ 83 84 if (AcpiGbl_ReducedHardware) 85 { 86 return_ACPI_STATUS (AE_OK); 87 } 88 89 /* Attempt installation of the global lock handler */ 90 91 Status = AcpiInstallFixedEventHandler (ACPI_EVENT_GLOBAL, 92 AcpiEvGlobalLockHandler, NULL); 93 94 /* 95 * If the global lock does not exist on this platform, the attempt to 96 * enable GBL_STATUS will fail (the GBL_ENABLE bit will not stick). 97 * Map to AE_OK, but mark global lock as not present. Any attempt to 98 * actually use the global lock will be flagged with an error. 99 */ 100 AcpiGbl_GlobalLockPresent = FALSE; 101 if (Status == AE_NO_HARDWARE_RESPONSE) 102 { 103 ACPI_ERROR ((AE_INFO, 104 "No response from Global Lock hardware, disabling lock")); 105 106 return_ACPI_STATUS (AE_OK); 107 } 108 109 Status = AcpiOsCreateLock (&AcpiGbl_GlobalLockPendingLock); 110 if (ACPI_FAILURE (Status)) 111 { 112 return_ACPI_STATUS (Status); 113 } 114 115 AcpiGbl_GlobalLockPending = FALSE; 116 AcpiGbl_GlobalLockPresent = TRUE; 117 return_ACPI_STATUS (Status); 118} 119 120 121/******************************************************************************* 122 * 123 * FUNCTION: AcpiEvRemoveGlobalLockHandler 124 * 125 * PARAMETERS: None 126 * 127 * RETURN: Status 128 * 129 * DESCRIPTION: Remove the handler for the Global Lock 130 * 131 ******************************************************************************/ 132 133ACPI_STATUS 134AcpiEvRemoveGlobalLockHandler ( 135 void) 136{ 137 ACPI_STATUS Status; 138 139 140 ACPI_FUNCTION_TRACE (EvRemoveGlobalLockHandler); 141 142 AcpiGbl_GlobalLockPresent = FALSE; 143 Status = AcpiRemoveFixedEventHandler (ACPI_EVENT_GLOBAL, 144 AcpiEvGlobalLockHandler); 145 146 return_ACPI_STATUS (Status); 147} 148 149 150/******************************************************************************* 151 * 152 * FUNCTION: AcpiEvGlobalLockHandler 153 * 154 * PARAMETERS: Context - From thread interface, not used 155 * 156 * RETURN: ACPI_INTERRUPT_HANDLED 157 * 158 * DESCRIPTION: Invoked directly from the SCI handler when a global lock 159 * release interrupt occurs. If there is actually a pending 160 * request for the lock, signal the waiting thread. 161 * 162 ******************************************************************************/ 163 164static UINT32 165AcpiEvGlobalLockHandler ( 166 void *Context) 167{ 168 ACPI_STATUS Status; 169 ACPI_CPU_FLAGS Flags; 170 171 172 Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock); 173 174 /* 175 * If a request for the global lock is not actually pending, 176 * we are done. This handles "spurious" global lock interrupts 177 * which are possible (and have been seen) with bad BIOSs. 178 */ 179 if (!AcpiGbl_GlobalLockPending) 180 { 181 goto CleanupAndExit; 182 } 183 184 /* 185 * Send a unit to the global lock semaphore. The actual acquisition 186 * of the global lock will be performed by the waiting thread. 187 */ 188 Status = AcpiOsSignalSemaphore (AcpiGbl_GlobalLockSemaphore, 1); 189 if (ACPI_FAILURE (Status)) 190 { 191 ACPI_ERROR ((AE_INFO, "Could not signal Global Lock semaphore")); 192 } 193 194 AcpiGbl_GlobalLockPending = FALSE; 195 196 197CleanupAndExit: 198 199 AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags); 200 return (ACPI_INTERRUPT_HANDLED); 201} 202 203 204/****************************************************************************** 205 * 206 * FUNCTION: AcpiEvAcquireGlobalLock 207 * 208 * PARAMETERS: Timeout - Max time to wait for the lock, in millisec. 209 * 210 * RETURN: Status 211 * 212 * DESCRIPTION: Attempt to gain ownership of the Global Lock. 213 * 214 * MUTEX: Interpreter must be locked 215 * 216 * Note: The original implementation allowed multiple threads to "acquire" the 217 * Global Lock, and the OS would hold the lock until the last thread had 218 * released it. However, this could potentially starve the BIOS out of the 219 * lock, especially in the case where there is a tight handshake between the 220 * Embedded Controller driver and the BIOS. Therefore, this implementation 221 * allows only one thread to acquire the HW Global Lock at a time, and makes 222 * the global lock appear as a standard mutex on the OS side. 223 * 224 *****************************************************************************/ 225 226ACPI_STATUS 227AcpiEvAcquireGlobalLock ( 228 UINT16 Timeout) 229{ 230 ACPI_CPU_FLAGS Flags; 231 ACPI_STATUS Status; 232 BOOLEAN Acquired = FALSE; 233 234 235 ACPI_FUNCTION_TRACE (EvAcquireGlobalLock); 236 237 238 /* 239 * Only one thread can acquire the GL at a time, the GlobalLockMutex 240 * enforces this. This interface releases the interpreter if we must wait. 241 */ 242 Status = AcpiExSystemWaitMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex, 243 Timeout); 244 if (ACPI_FAILURE (Status)) 245 { 246 return_ACPI_STATUS (Status); 247 } 248 249 /* 250 * Update the global lock handle and check for wraparound. The handle is 251 * only used for the external global lock interfaces, but it is updated 252 * here to properly handle the case where a single thread may acquire the 253 * lock via both the AML and the AcpiAcquireGlobalLock interfaces. The 254 * handle is therefore updated on the first acquire from a given thread 255 * regardless of where the acquisition request originated. 256 */ 257 AcpiGbl_GlobalLockHandle++; 258 if (AcpiGbl_GlobalLockHandle == 0) 259 { 260 AcpiGbl_GlobalLockHandle = 1; 261 } 262 263 /* 264 * Make sure that a global lock actually exists. If not, just 265 * treat the lock as a standard mutex. 266 */ 267 if (!AcpiGbl_GlobalLockPresent) 268 { 269 AcpiGbl_GlobalLockAcquired = TRUE; 270 return_ACPI_STATUS (AE_OK); 271 } 272 273 Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock); 274 275 do 276 { 277 /* Attempt to acquire the actual hardware lock */ 278 279 ACPI_ACQUIRE_GLOBAL_LOCK (AcpiGbl_FACS, Acquired); 280 if (Acquired) 281 { 282 AcpiGbl_GlobalLockAcquired = TRUE; 283 ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, 284 "Acquired hardware Global Lock\n")); 285 break; 286 } 287 288 /* 289 * Did not get the lock. The pending bit was set above, and 290 * we must now wait until we receive the global lock 291 * released interrupt. 292 */ 293 AcpiGbl_GlobalLockPending = TRUE; 294 AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags); 295 296 ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, 297 "Waiting for hardware Global Lock\n")); 298 299 /* 300 * Wait for handshake with the global lock interrupt handler. 301 * This interface releases the interpreter if we must wait. 302 */ 303 Status = AcpiExSystemWaitSemaphore (AcpiGbl_GlobalLockSemaphore, 304 ACPI_WAIT_FOREVER); 305 306 Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock); 307 308 } while (ACPI_SUCCESS (Status)); 309 310 AcpiGbl_GlobalLockPending = FALSE; 311 AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags); 312 313 return_ACPI_STATUS (Status); 314} 315 316 317/******************************************************************************* 318 * 319 * FUNCTION: AcpiEvReleaseGlobalLock 320 * 321 * PARAMETERS: None 322 * 323 * RETURN: Status 324 * 325 * DESCRIPTION: Releases ownership of the Global Lock. 326 * 327 ******************************************************************************/ 328 329ACPI_STATUS 330AcpiEvReleaseGlobalLock ( 331 void) 332{ 333 BOOLEAN Pending = FALSE; 334 ACPI_STATUS Status = AE_OK; 335 336 337 ACPI_FUNCTION_TRACE (EvReleaseGlobalLock); 338 339 340 /* Lock must be already acquired */ 341 342 if (!AcpiGbl_GlobalLockAcquired) 343 { 344 ACPI_WARNING ((AE_INFO, 345 "Cannot release the ACPI Global Lock, it has not been acquired")); 346 return_ACPI_STATUS (AE_NOT_ACQUIRED); 347 } 348 349 if (AcpiGbl_GlobalLockPresent) 350 { 351 /* Allow any thread to release the lock */ 352 353 ACPI_RELEASE_GLOBAL_LOCK (AcpiGbl_FACS, Pending); 354 355 /* 356 * If the pending bit was set, we must write GBL_RLS to the control 357 * register 358 */ 359 if (Pending) 360 { 361 Status = AcpiWriteBitRegister ( 362 ACPI_BITREG_GLOBAL_LOCK_RELEASE, ACPI_ENABLE_EVENT); 363 } 364 365 ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Released hardware Global Lock\n")); 366 } 367 368 AcpiGbl_GlobalLockAcquired = FALSE; 369 370 /* Release the local GL mutex */ 371 372 AcpiOsReleaseMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex); 373 return_ACPI_STATUS (Status); 374} 375