1 /****************************************************************************** 2 * 3 * Module Name: evglock - Global Lock support 4 * 5 *****************************************************************************/ 6 7 /* 8 * Copyright (C) 2000 - 2013, 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 #if (!ACPI_REDUCED_HARDWARE) /* Entire module */ 53 54 /* Local prototypes */ 55 56 static UINT32 57 AcpiEvGlobalLockHandler ( 58 void *Context); 59 60 61 /******************************************************************************* 62 * 63 * FUNCTION: AcpiEvInitGlobalLockHandler 64 * 65 * PARAMETERS: None 66 * 67 * RETURN: Status 68 * 69 * DESCRIPTION: Install a handler for the global lock release event 70 * 71 ******************************************************************************/ 72 73 ACPI_STATUS 74 AcpiEvInitGlobalLockHandler ( 75 void) 76 { 77 ACPI_STATUS Status; 78 79 80 ACPI_FUNCTION_TRACE (EvInitGlobalLockHandler); 81 82 83 /* If Hardware Reduced flag is set, there is no global lock */ 84 85 if (AcpiGbl_ReducedHardware) 86 { 87 return_ACPI_STATUS (AE_OK); 88 } 89 90 /* Attempt installation of the global lock handler */ 91 92 Status = AcpiInstallFixedEventHandler (ACPI_EVENT_GLOBAL, 93 AcpiEvGlobalLockHandler, NULL); 94 95 /* 96 * If the global lock does not exist on this platform, the attempt to 97 * enable GBL_STATUS will fail (the GBL_ENABLE bit will not stick). 98 * Map to AE_OK, but mark global lock as not present. Any attempt to 99 * actually use the global lock will be flagged with an error. 100 */ 101 AcpiGbl_GlobalLockPresent = FALSE; 102 if (Status == AE_NO_HARDWARE_RESPONSE) 103 { 104 ACPI_ERROR ((AE_INFO, 105 "No response from Global Lock hardware, disabling lock")); 106 107 return_ACPI_STATUS (AE_OK); 108 } 109 110 Status = AcpiOsCreateLock (&AcpiGbl_GlobalLockPendingLock); 111 if (ACPI_FAILURE (Status)) 112 { 113 return_ACPI_STATUS (Status); 114 } 115 116 AcpiGbl_GlobalLockPending = FALSE; 117 AcpiGbl_GlobalLockPresent = TRUE; 118 return_ACPI_STATUS (Status); 119 } 120 121 122 /******************************************************************************* 123 * 124 * FUNCTION: AcpiEvRemoveGlobalLockHandler 125 * 126 * PARAMETERS: None 127 * 128 * RETURN: Status 129 * 130 * DESCRIPTION: Remove the handler for the Global Lock 131 * 132 ******************************************************************************/ 133 134 ACPI_STATUS 135 AcpiEvRemoveGlobalLockHandler ( 136 void) 137 { 138 ACPI_STATUS Status; 139 140 141 ACPI_FUNCTION_TRACE (EvRemoveGlobalLockHandler); 142 143 AcpiGbl_GlobalLockPresent = FALSE; 144 Status = AcpiRemoveFixedEventHandler (ACPI_EVENT_GLOBAL, 145 AcpiEvGlobalLockHandler); 146 147 AcpiOsDeleteLock (AcpiGbl_GlobalLockPendingLock); 148 return_ACPI_STATUS (Status); 149 } 150 151 152 /******************************************************************************* 153 * 154 * FUNCTION: AcpiEvGlobalLockHandler 155 * 156 * PARAMETERS: Context - From thread interface, not used 157 * 158 * RETURN: ACPI_INTERRUPT_HANDLED 159 * 160 * DESCRIPTION: Invoked directly from the SCI handler when a global lock 161 * release interrupt occurs. If there is actually a pending 162 * request for the lock, signal the waiting thread. 163 * 164 ******************************************************************************/ 165 166 static UINT32 167 AcpiEvGlobalLockHandler ( 168 void *Context) 169 { 170 ACPI_STATUS Status; 171 ACPI_CPU_FLAGS Flags; 172 173 174 Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock); 175 176 /* 177 * If a request for the global lock is not actually pending, 178 * we are done. This handles "spurious" global lock interrupts 179 * which are possible (and have been seen) with bad BIOSs. 180 */ 181 if (!AcpiGbl_GlobalLockPending) 182 { 183 goto CleanupAndExit; 184 } 185 186 /* 187 * Send a unit to the global lock semaphore. The actual acquisition 188 * of the global lock will be performed by the waiting thread. 189 */ 190 Status = AcpiOsSignalSemaphore (AcpiGbl_GlobalLockSemaphore, 1); 191 if (ACPI_FAILURE (Status)) 192 { 193 ACPI_ERROR ((AE_INFO, "Could not signal Global Lock semaphore")); 194 } 195 196 AcpiGbl_GlobalLockPending = FALSE; 197 198 199 CleanupAndExit: 200 201 AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags); 202 return (ACPI_INTERRUPT_HANDLED); 203 } 204 205 206 /****************************************************************************** 207 * 208 * FUNCTION: AcpiEvAcquireGlobalLock 209 * 210 * PARAMETERS: Timeout - Max time to wait for the lock, in millisec. 211 * 212 * RETURN: Status 213 * 214 * DESCRIPTION: Attempt to gain ownership of the Global Lock. 215 * 216 * MUTEX: Interpreter must be locked 217 * 218 * Note: The original implementation allowed multiple threads to "acquire" the 219 * Global Lock, and the OS would hold the lock until the last thread had 220 * released it. However, this could potentially starve the BIOS out of the 221 * lock, especially in the case where there is a tight handshake between the 222 * Embedded Controller driver and the BIOS. Therefore, this implementation 223 * allows only one thread to acquire the HW Global Lock at a time, and makes 224 * the global lock appear as a standard mutex on the OS side. 225 * 226 *****************************************************************************/ 227 228 ACPI_STATUS 229 AcpiEvAcquireGlobalLock ( 230 UINT16 Timeout) 231 { 232 ACPI_CPU_FLAGS Flags; 233 ACPI_STATUS Status; 234 BOOLEAN Acquired = FALSE; 235 236 237 ACPI_FUNCTION_TRACE (EvAcquireGlobalLock); 238 239 240 /* 241 * Only one thread can acquire the GL at a time, the GlobalLockMutex 242 * enforces this. This interface releases the interpreter if we must wait. 243 */ 244 Status = AcpiExSystemWaitMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex, 245 Timeout); 246 if (ACPI_FAILURE (Status)) 247 { 248 return_ACPI_STATUS (Status); 249 } 250 251 /* 252 * Update the global lock handle and check for wraparound. The handle is 253 * only used for the external global lock interfaces, but it is updated 254 * here to properly handle the case where a single thread may acquire the 255 * lock via both the AML and the AcpiAcquireGlobalLock interfaces. The 256 * handle is therefore updated on the first acquire from a given thread 257 * regardless of where the acquisition request originated. 258 */ 259 AcpiGbl_GlobalLockHandle++; 260 if (AcpiGbl_GlobalLockHandle == 0) 261 { 262 AcpiGbl_GlobalLockHandle = 1; 263 } 264 265 /* 266 * Make sure that a global lock actually exists. If not, just 267 * treat the lock as a standard mutex. 268 */ 269 if (!AcpiGbl_GlobalLockPresent) 270 { 271 AcpiGbl_GlobalLockAcquired = TRUE; 272 return_ACPI_STATUS (AE_OK); 273 } 274 275 Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock); 276 277 do 278 { 279 /* Attempt to acquire the actual hardware lock */ 280 281 ACPI_ACQUIRE_GLOBAL_LOCK (AcpiGbl_FACS, Acquired); 282 if (Acquired) 283 { 284 AcpiGbl_GlobalLockAcquired = TRUE; 285 ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, 286 "Acquired hardware Global Lock\n")); 287 break; 288 } 289 290 /* 291 * Did not get the lock. The pending bit was set above, and 292 * we must now wait until we receive the global lock 293 * released interrupt. 294 */ 295 AcpiGbl_GlobalLockPending = TRUE; 296 AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags); 297 298 ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, 299 "Waiting for hardware Global Lock\n")); 300 301 /* 302 * Wait for handshake with the global lock interrupt handler. 303 * This interface releases the interpreter if we must wait. 304 */ 305 Status = AcpiExSystemWaitSemaphore (AcpiGbl_GlobalLockSemaphore, 306 ACPI_WAIT_FOREVER); 307 308 Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock); 309 310 } while (ACPI_SUCCESS (Status)); 311 312 AcpiGbl_GlobalLockPending = FALSE; 313 AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags); 314 315 return_ACPI_STATUS (Status); 316 } 317 318 319 /******************************************************************************* 320 * 321 * FUNCTION: AcpiEvReleaseGlobalLock 322 * 323 * PARAMETERS: None 324 * 325 * RETURN: Status 326 * 327 * DESCRIPTION: Releases ownership of the Global Lock. 328 * 329 ******************************************************************************/ 330 331 ACPI_STATUS 332 AcpiEvReleaseGlobalLock ( 333 void) 334 { 335 BOOLEAN Pending = FALSE; 336 ACPI_STATUS Status = AE_OK; 337 338 339 ACPI_FUNCTION_TRACE (EvReleaseGlobalLock); 340 341 342 /* Lock must be already acquired */ 343 344 if (!AcpiGbl_GlobalLockAcquired) 345 { 346 ACPI_WARNING ((AE_INFO, 347 "Cannot release the ACPI Global Lock, it has not been acquired")); 348 return_ACPI_STATUS (AE_NOT_ACQUIRED); 349 } 350 351 if (AcpiGbl_GlobalLockPresent) 352 { 353 /* Allow any thread to release the lock */ 354 355 ACPI_RELEASE_GLOBAL_LOCK (AcpiGbl_FACS, Pending); 356 357 /* 358 * If the pending bit was set, we must write GBL_RLS to the control 359 * register 360 */ 361 if (Pending) 362 { 363 Status = AcpiWriteBitRegister ( 364 ACPI_BITREG_GLOBAL_LOCK_RELEASE, ACPI_ENABLE_EVENT); 365 } 366 367 ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Released hardware Global Lock\n")); 368 } 369 370 AcpiGbl_GlobalLockAcquired = FALSE; 371 372 /* Release the local GL mutex */ 373 374 AcpiOsReleaseMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex); 375 return_ACPI_STATUS (Status); 376 } 377 378 #endif /* !ACPI_REDUCED_HARDWARE */ 379