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