| 1 | /****************************************************************************** |
| 2 | * |
| 3 | * Module Name: evglock - Global Lock support |
| 4 | * |
| 5 | *****************************************************************************/ |
| 6 | |
| 7 | /* |
| 8 | * Copyright (C) 2000 - 2016, 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 | #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 | |
| 144 | AcpiGbl_GlobalLockPresent = FALSE; |
| 145 | Status = AcpiRemoveFixedEventHandler (ACPI_EVENT_GLOBAL, |
| 146 | AcpiEvGlobalLockHandler); |
| 147 | |
| 148 | AcpiOsDeleteLock (AcpiGbl_GlobalLockPendingLock); |
| 149 | return_ACPI_STATUS (Status); |
| 150 | } |
| 151 | |
| 152 | |
| 153 | /******************************************************************************* |
| 154 | * |
| 155 | * FUNCTION: AcpiEvGlobalLockHandler |
| 156 | * |
| 157 | * PARAMETERS: Context - From thread interface, not used |
| 158 | * |
| 159 | * RETURN: ACPI_INTERRUPT_HANDLED |
| 160 | * |
| 161 | * DESCRIPTION: Invoked directly from the SCI handler when a global lock |
| 162 | * release interrupt occurs. If there is actually a pending |
| 163 | * request for the lock, signal the waiting thread. |
| 164 | * |
| 165 | ******************************************************************************/ |
| 166 | |
| 167 | static UINT32 |
| 168 | AcpiEvGlobalLockHandler ( |
| 169 | void *Context) |
| 170 | { |
| 171 | ACPI_STATUS Status; |
| 172 | ACPI_CPU_FLAGS Flags; |
| 173 | |
| 174 | |
| 175 | Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock); |
| 176 | |
| 177 | /* |
| 178 | * If a request for the global lock is not actually pending, |
| 179 | * we are done. This handles "spurious" global lock interrupts |
| 180 | * which are possible (and have been seen) with bad BIOSs. |
| 181 | */ |
| 182 | if (!AcpiGbl_GlobalLockPending) |
| 183 | { |
| 184 | goto CleanupAndExit; |
| 185 | } |
| 186 | |
| 187 | /* |
| 188 | * Send a unit to the global lock semaphore. The actual acquisition |
| 189 | * of the global lock will be performed by the waiting thread. |
| 190 | */ |
| 191 | Status = AcpiOsSignalSemaphore (AcpiGbl_GlobalLockSemaphore, 1); |
| 192 | if (ACPI_FAILURE (Status)) |
| 193 | { |
| 194 | ACPI_ERROR ((AE_INFO, "Could not signal Global Lock semaphore" )); |
| 195 | } |
| 196 | |
| 197 | AcpiGbl_GlobalLockPending = FALSE; |
| 198 | |
| 199 | |
| 200 | CleanupAndExit: |
| 201 | |
| 202 | AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags); |
| 203 | return (ACPI_INTERRUPT_HANDLED); |
| 204 | } |
| 205 | |
| 206 | |
| 207 | /****************************************************************************** |
| 208 | * |
| 209 | * FUNCTION: AcpiEvAcquireGlobalLock |
| 210 | * |
| 211 | * PARAMETERS: Timeout - Max time to wait for the lock, in millisec. |
| 212 | * |
| 213 | * RETURN: Status |
| 214 | * |
| 215 | * DESCRIPTION: Attempt to gain ownership of the Global Lock. |
| 216 | * |
| 217 | * MUTEX: Interpreter must be locked |
| 218 | * |
| 219 | * Note: The original implementation allowed multiple threads to "acquire" the |
| 220 | * Global Lock, and the OS would hold the lock until the last thread had |
| 221 | * released it. However, this could potentially starve the BIOS out of the |
| 222 | * lock, especially in the case where there is a tight handshake between the |
| 223 | * Embedded Controller driver and the BIOS. Therefore, this implementation |
| 224 | * allows only one thread to acquire the HW Global Lock at a time, and makes |
| 225 | * the global lock appear as a standard mutex on the OS side. |
| 226 | * |
| 227 | *****************************************************************************/ |
| 228 | |
| 229 | ACPI_STATUS |
| 230 | AcpiEvAcquireGlobalLock ( |
| 231 | UINT16 Timeout) |
| 232 | { |
| 233 | ACPI_CPU_FLAGS Flags; |
| 234 | ACPI_STATUS Status; |
| 235 | BOOLEAN Acquired = FALSE; |
| 236 | |
| 237 | |
| 238 | ACPI_FUNCTION_TRACE (EvAcquireGlobalLock); |
| 239 | |
| 240 | |
| 241 | /* |
| 242 | * Only one thread can acquire the GL at a time, the GlobalLockMutex |
| 243 | * enforces this. This interface releases the interpreter if we must wait. |
| 244 | */ |
| 245 | Status = AcpiExSystemWaitMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex, |
| 246 | Timeout); |
| 247 | if (ACPI_FAILURE (Status)) |
| 248 | { |
| 249 | return_ACPI_STATUS (Status); |
| 250 | } |
| 251 | |
| 252 | /* |
| 253 | * Update the global lock handle and check for wraparound. The handle is |
| 254 | * only used for the external global lock interfaces, but it is updated |
| 255 | * here to properly handle the case where a single thread may acquire the |
| 256 | * lock via both the AML and the AcpiAcquireGlobalLock interfaces. The |
| 257 | * handle is therefore updated on the first acquire from a given thread |
| 258 | * regardless of where the acquisition request originated. |
| 259 | */ |
| 260 | AcpiGbl_GlobalLockHandle++; |
| 261 | if (AcpiGbl_GlobalLockHandle == 0) |
| 262 | { |
| 263 | AcpiGbl_GlobalLockHandle = 1; |
| 264 | } |
| 265 | |
| 266 | /* |
| 267 | * Make sure that a global lock actually exists. If not, just |
| 268 | * treat the lock as a standard mutex. |
| 269 | */ |
| 270 | if (!AcpiGbl_GlobalLockPresent) |
| 271 | { |
| 272 | AcpiGbl_GlobalLockAcquired = TRUE; |
| 273 | return_ACPI_STATUS (AE_OK); |
| 274 | } |
| 275 | |
| 276 | Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock); |
| 277 | |
| 278 | do |
| 279 | { |
| 280 | /* Attempt to acquire the actual hardware lock */ |
| 281 | |
| 282 | ACPI_ACQUIRE_GLOBAL_LOCK (AcpiGbl_FACS, Acquired); |
| 283 | if (Acquired) |
| 284 | { |
| 285 | AcpiGbl_GlobalLockAcquired = TRUE; |
| 286 | ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, |
| 287 | "Acquired hardware Global Lock\n" )); |
| 288 | break; |
| 289 | } |
| 290 | |
| 291 | /* |
| 292 | * Did not get the lock. The pending bit was set above, and |
| 293 | * we must now wait until we receive the global lock |
| 294 | * released interrupt. |
| 295 | */ |
| 296 | AcpiGbl_GlobalLockPending = TRUE; |
| 297 | AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags); |
| 298 | |
| 299 | ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, |
| 300 | "Waiting for hardware Global Lock\n" )); |
| 301 | |
| 302 | /* |
| 303 | * Wait for handshake with the global lock interrupt handler. |
| 304 | * This interface releases the interpreter if we must wait. |
| 305 | */ |
| 306 | Status = AcpiExSystemWaitSemaphore ( |
| 307 | AcpiGbl_GlobalLockSemaphore, ACPI_WAIT_FOREVER); |
| 308 | |
| 309 | Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock); |
| 310 | |
| 311 | } while (ACPI_SUCCESS (Status)); |
| 312 | |
| 313 | AcpiGbl_GlobalLockPending = FALSE; |
| 314 | AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags); |
| 315 | |
| 316 | return_ACPI_STATUS (Status); |
| 317 | } |
| 318 | |
| 319 | |
| 320 | /******************************************************************************* |
| 321 | * |
| 322 | * FUNCTION: AcpiEvReleaseGlobalLock |
| 323 | * |
| 324 | * PARAMETERS: None |
| 325 | * |
| 326 | * RETURN: Status |
| 327 | * |
| 328 | * DESCRIPTION: Releases ownership of the Global Lock. |
| 329 | * |
| 330 | ******************************************************************************/ |
| 331 | |
| 332 | ACPI_STATUS |
| 333 | AcpiEvReleaseGlobalLock ( |
| 334 | void) |
| 335 | { |
| 336 | BOOLEAN Pending = FALSE; |
| 337 | ACPI_STATUS Status = AE_OK; |
| 338 | |
| 339 | |
| 340 | ACPI_FUNCTION_TRACE (EvReleaseGlobalLock); |
| 341 | |
| 342 | |
| 343 | /* Lock must be already acquired */ |
| 344 | |
| 345 | if (!AcpiGbl_GlobalLockAcquired) |
| 346 | { |
| 347 | ACPI_WARNING ((AE_INFO, |
| 348 | "Cannot release the ACPI Global Lock, it has not been acquired" )); |
| 349 | return_ACPI_STATUS (AE_NOT_ACQUIRED); |
| 350 | } |
| 351 | |
| 352 | if (AcpiGbl_GlobalLockPresent) |
| 353 | { |
| 354 | /* Allow any thread to release the lock */ |
| 355 | |
| 356 | ACPI_RELEASE_GLOBAL_LOCK (AcpiGbl_FACS, Pending); |
| 357 | |
| 358 | /* |
| 359 | * If the pending bit was set, we must write GBL_RLS to the control |
| 360 | * register |
| 361 | */ |
| 362 | if (Pending) |
| 363 | { |
| 364 | Status = AcpiWriteBitRegister ( |
| 365 | ACPI_BITREG_GLOBAL_LOCK_RELEASE, ACPI_ENABLE_EVENT); |
| 366 | } |
| 367 | |
| 368 | ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Released hardware Global Lock\n" )); |
| 369 | } |
| 370 | |
| 371 | AcpiGbl_GlobalLockAcquired = FALSE; |
| 372 | |
| 373 | /* Release the local GL mutex */ |
| 374 | |
| 375 | AcpiOsReleaseMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex); |
| 376 | return_ACPI_STATUS (Status); |
| 377 | } |
| 378 | |
| 379 | #endif /* !ACPI_REDUCED_HARDWARE */ |
| 380 | |