Erik Schmauss | 9585763 | 2018-03-14 16:13:07 -0700 | [diff] [blame] | 1 | // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 |
Bob Moore | 0f6896f | 2011-04-13 11:33:17 +0800 | [diff] [blame] | 2 | /****************************************************************************** |
| 3 | * |
| 4 | * Module Name: evglock - Global Lock support |
| 5 | * |
Bob Moore | da6f832 | 2018-01-04 10:06:38 -0800 | [diff] [blame] | 6 | * Copyright (C) 2000 - 2018, Intel Corp. |
Bob Moore | 0f6896f | 2011-04-13 11:33:17 +0800 | [diff] [blame] | 7 | * |
Erik Schmauss | 9585763 | 2018-03-14 16:13:07 -0700 | [diff] [blame] | 8 | *****************************************************************************/ |
Bob Moore | 0f6896f | 2011-04-13 11:33:17 +0800 | [diff] [blame] | 9 | |
| 10 | #include <acpi/acpi.h> |
| 11 | #include "accommon.h" |
| 12 | #include "acevents.h" |
| 13 | #include "acinterp.h" |
| 14 | |
| 15 | #define _COMPONENT ACPI_EVENTS |
| 16 | ACPI_MODULE_NAME("evglock") |
Bob Moore | 33620c5 | 2012-02-14 18:14:27 +0800 | [diff] [blame] | 17 | #if (!ACPI_REDUCED_HARDWARE) /* Entire module */ |
Bob Moore | 0f6896f | 2011-04-13 11:33:17 +0800 | [diff] [blame] | 18 | /* Local prototypes */ |
| 19 | static u32 acpi_ev_global_lock_handler(void *context); |
| 20 | |
| 21 | /******************************************************************************* |
| 22 | * |
| 23 | * FUNCTION: acpi_ev_init_global_lock_handler |
| 24 | * |
| 25 | * PARAMETERS: None |
| 26 | * |
| 27 | * RETURN: Status |
| 28 | * |
| 29 | * DESCRIPTION: Install a handler for the global lock release event |
| 30 | * |
| 31 | ******************************************************************************/ |
| 32 | |
| 33 | acpi_status acpi_ev_init_global_lock_handler(void) |
| 34 | { |
| 35 | acpi_status status; |
| 36 | |
| 37 | ACPI_FUNCTION_TRACE(ev_init_global_lock_handler); |
| 38 | |
Bob Moore | 22e5b40 | 2011-11-16 10:57:28 +0800 | [diff] [blame] | 39 | /* If Hardware Reduced flag is set, there is no global lock */ |
| 40 | |
| 41 | if (acpi_gbl_reduced_hardware) { |
| 42 | return_ACPI_STATUS(AE_OK); |
| 43 | } |
| 44 | |
Bob Moore | 0f6896f | 2011-04-13 11:33:17 +0800 | [diff] [blame] | 45 | /* Attempt installation of the global lock handler */ |
| 46 | |
| 47 | status = acpi_install_fixed_event_handler(ACPI_EVENT_GLOBAL, |
| 48 | acpi_ev_global_lock_handler, |
| 49 | NULL); |
| 50 | |
| 51 | /* |
| 52 | * If the global lock does not exist on this platform, the attempt to |
| 53 | * enable GBL_STATUS will fail (the GBL_ENABLE bit will not stick). |
| 54 | * Map to AE_OK, but mark global lock as not present. Any attempt to |
| 55 | * actually use the global lock will be flagged with an error. |
| 56 | */ |
| 57 | acpi_gbl_global_lock_present = FALSE; |
| 58 | if (status == AE_NO_HARDWARE_RESPONSE) { |
| 59 | ACPI_ERROR((AE_INFO, |
| 60 | "No response from Global Lock hardware, disabling lock")); |
| 61 | |
| 62 | return_ACPI_STATUS(AE_OK); |
| 63 | } |
| 64 | |
| 65 | status = acpi_os_create_lock(&acpi_gbl_global_lock_pending_lock); |
| 66 | if (ACPI_FAILURE(status)) { |
| 67 | return_ACPI_STATUS(status); |
| 68 | } |
| 69 | |
| 70 | acpi_gbl_global_lock_pending = FALSE; |
| 71 | acpi_gbl_global_lock_present = TRUE; |
| 72 | return_ACPI_STATUS(status); |
| 73 | } |
| 74 | |
| 75 | /******************************************************************************* |
| 76 | * |
| 77 | * FUNCTION: acpi_ev_remove_global_lock_handler |
| 78 | * |
| 79 | * PARAMETERS: None |
| 80 | * |
| 81 | * RETURN: Status |
| 82 | * |
| 83 | * DESCRIPTION: Remove the handler for the Global Lock |
| 84 | * |
| 85 | ******************************************************************************/ |
| 86 | |
| 87 | acpi_status acpi_ev_remove_global_lock_handler(void) |
| 88 | { |
| 89 | acpi_status status; |
| 90 | |
| 91 | ACPI_FUNCTION_TRACE(ev_remove_global_lock_handler); |
| 92 | |
| 93 | acpi_gbl_global_lock_present = FALSE; |
| 94 | status = acpi_remove_fixed_event_handler(ACPI_EVENT_GLOBAL, |
| 95 | acpi_ev_global_lock_handler); |
| 96 | |
Tomasz Nowicki | 9dae7bb | 2013-06-08 00:59:55 +0000 | [diff] [blame] | 97 | acpi_os_delete_lock(acpi_gbl_global_lock_pending_lock); |
Bob Moore | 0f6896f | 2011-04-13 11:33:17 +0800 | [diff] [blame] | 98 | return_ACPI_STATUS(status); |
| 99 | } |
| 100 | |
| 101 | /******************************************************************************* |
| 102 | * |
| 103 | * FUNCTION: acpi_ev_global_lock_handler |
| 104 | * |
Bob Moore | ba494be | 2012-07-12 09:40:10 +0800 | [diff] [blame] | 105 | * PARAMETERS: context - From thread interface, not used |
Bob Moore | 0f6896f | 2011-04-13 11:33:17 +0800 | [diff] [blame] | 106 | * |
| 107 | * RETURN: ACPI_INTERRUPT_HANDLED |
| 108 | * |
| 109 | * DESCRIPTION: Invoked directly from the SCI handler when a global lock |
| 110 | * release interrupt occurs. If there is actually a pending |
| 111 | * request for the lock, signal the waiting thread. |
| 112 | * |
| 113 | ******************************************************************************/ |
| 114 | |
| 115 | static u32 acpi_ev_global_lock_handler(void *context) |
| 116 | { |
| 117 | acpi_status status; |
| 118 | acpi_cpu_flags flags; |
| 119 | |
| 120 | flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock); |
| 121 | |
| 122 | /* |
| 123 | * If a request for the global lock is not actually pending, |
| 124 | * we are done. This handles "spurious" global lock interrupts |
| 125 | * which are possible (and have been seen) with bad BIOSs. |
| 126 | */ |
| 127 | if (!acpi_gbl_global_lock_pending) { |
| 128 | goto cleanup_and_exit; |
| 129 | } |
| 130 | |
| 131 | /* |
| 132 | * Send a unit to the global lock semaphore. The actual acquisition |
| 133 | * of the global lock will be performed by the waiting thread. |
| 134 | */ |
| 135 | status = acpi_os_signal_semaphore(acpi_gbl_global_lock_semaphore, 1); |
| 136 | if (ACPI_FAILURE(status)) { |
| 137 | ACPI_ERROR((AE_INFO, "Could not signal Global Lock semaphore")); |
| 138 | } |
| 139 | |
| 140 | acpi_gbl_global_lock_pending = FALSE; |
| 141 | |
Lv Zheng | 10622bf | 2013-10-29 09:30:02 +0800 | [diff] [blame] | 142 | cleanup_and_exit: |
Bob Moore | 0f6896f | 2011-04-13 11:33:17 +0800 | [diff] [blame] | 143 | |
| 144 | acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags); |
| 145 | return (ACPI_INTERRUPT_HANDLED); |
| 146 | } |
| 147 | |
| 148 | /****************************************************************************** |
| 149 | * |
| 150 | * FUNCTION: acpi_ev_acquire_global_lock |
| 151 | * |
Bob Moore | ba494be | 2012-07-12 09:40:10 +0800 | [diff] [blame] | 152 | * PARAMETERS: timeout - Max time to wait for the lock, in millisec. |
Bob Moore | 0f6896f | 2011-04-13 11:33:17 +0800 | [diff] [blame] | 153 | * |
| 154 | * RETURN: Status |
| 155 | * |
| 156 | * DESCRIPTION: Attempt to gain ownership of the Global Lock. |
| 157 | * |
| 158 | * MUTEX: Interpreter must be locked |
| 159 | * |
| 160 | * Note: The original implementation allowed multiple threads to "acquire" the |
| 161 | * Global Lock, and the OS would hold the lock until the last thread had |
| 162 | * released it. However, this could potentially starve the BIOS out of the |
| 163 | * lock, especially in the case where there is a tight handshake between the |
| 164 | * Embedded Controller driver and the BIOS. Therefore, this implementation |
| 165 | * allows only one thread to acquire the HW Global Lock at a time, and makes |
| 166 | * the global lock appear as a standard mutex on the OS side. |
| 167 | * |
| 168 | *****************************************************************************/ |
| 169 | |
| 170 | acpi_status acpi_ev_acquire_global_lock(u16 timeout) |
| 171 | { |
| 172 | acpi_cpu_flags flags; |
| 173 | acpi_status status; |
| 174 | u8 acquired = FALSE; |
| 175 | |
| 176 | ACPI_FUNCTION_TRACE(ev_acquire_global_lock); |
| 177 | |
| 178 | /* |
| 179 | * Only one thread can acquire the GL at a time, the global_lock_mutex |
| 180 | * enforces this. This interface releases the interpreter if we must wait. |
| 181 | */ |
| 182 | status = |
| 183 | acpi_ex_system_wait_mutex(acpi_gbl_global_lock_mutex->mutex. |
| 184 | os_mutex, timeout); |
| 185 | if (ACPI_FAILURE(status)) { |
| 186 | return_ACPI_STATUS(status); |
| 187 | } |
| 188 | |
| 189 | /* |
| 190 | * Update the global lock handle and check for wraparound. The handle is |
| 191 | * only used for the external global lock interfaces, but it is updated |
| 192 | * here to properly handle the case where a single thread may acquire the |
| 193 | * lock via both the AML and the acpi_acquire_global_lock interfaces. The |
| 194 | * handle is therefore updated on the first acquire from a given thread |
| 195 | * regardless of where the acquisition request originated. |
| 196 | */ |
| 197 | acpi_gbl_global_lock_handle++; |
| 198 | if (acpi_gbl_global_lock_handle == 0) { |
| 199 | acpi_gbl_global_lock_handle = 1; |
| 200 | } |
| 201 | |
| 202 | /* |
| 203 | * Make sure that a global lock actually exists. If not, just |
| 204 | * treat the lock as a standard mutex. |
| 205 | */ |
| 206 | if (!acpi_gbl_global_lock_present) { |
| 207 | acpi_gbl_global_lock_acquired = TRUE; |
| 208 | return_ACPI_STATUS(AE_OK); |
| 209 | } |
| 210 | |
| 211 | flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock); |
| 212 | |
| 213 | do { |
| 214 | |
| 215 | /* Attempt to acquire the actual hardware lock */ |
| 216 | |
| 217 | ACPI_ACQUIRE_GLOBAL_LOCK(acpi_gbl_FACS, acquired); |
| 218 | if (acquired) { |
| 219 | acpi_gbl_global_lock_acquired = TRUE; |
| 220 | ACPI_DEBUG_PRINT((ACPI_DB_EXEC, |
| 221 | "Acquired hardware Global Lock\n")); |
| 222 | break; |
| 223 | } |
| 224 | |
| 225 | /* |
| 226 | * Did not get the lock. The pending bit was set above, and |
| 227 | * we must now wait until we receive the global lock |
| 228 | * released interrupt. |
| 229 | */ |
| 230 | acpi_gbl_global_lock_pending = TRUE; |
| 231 | acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags); |
| 232 | |
| 233 | ACPI_DEBUG_PRINT((ACPI_DB_EXEC, |
| 234 | "Waiting for hardware Global Lock\n")); |
| 235 | |
| 236 | /* |
| 237 | * Wait for handshake with the global lock interrupt handler. |
| 238 | * This interface releases the interpreter if we must wait. |
| 239 | */ |
| 240 | status = |
| 241 | acpi_ex_system_wait_semaphore |
| 242 | (acpi_gbl_global_lock_semaphore, ACPI_WAIT_FOREVER); |
| 243 | |
| 244 | flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock); |
| 245 | |
| 246 | } while (ACPI_SUCCESS(status)); |
| 247 | |
| 248 | acpi_gbl_global_lock_pending = FALSE; |
| 249 | acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags); |
| 250 | |
| 251 | return_ACPI_STATUS(status); |
| 252 | } |
| 253 | |
| 254 | /******************************************************************************* |
| 255 | * |
| 256 | * FUNCTION: acpi_ev_release_global_lock |
| 257 | * |
| 258 | * PARAMETERS: None |
| 259 | * |
| 260 | * RETURN: Status |
| 261 | * |
| 262 | * DESCRIPTION: Releases ownership of the Global Lock. |
| 263 | * |
| 264 | ******************************************************************************/ |
| 265 | |
| 266 | acpi_status acpi_ev_release_global_lock(void) |
| 267 | { |
| 268 | u8 pending = FALSE; |
| 269 | acpi_status status = AE_OK; |
| 270 | |
| 271 | ACPI_FUNCTION_TRACE(ev_release_global_lock); |
| 272 | |
| 273 | /* Lock must be already acquired */ |
| 274 | |
| 275 | if (!acpi_gbl_global_lock_acquired) { |
| 276 | ACPI_WARNING((AE_INFO, |
| 277 | "Cannot release the ACPI Global Lock, it has not been acquired")); |
| 278 | return_ACPI_STATUS(AE_NOT_ACQUIRED); |
| 279 | } |
| 280 | |
| 281 | if (acpi_gbl_global_lock_present) { |
| 282 | |
| 283 | /* Allow any thread to release the lock */ |
| 284 | |
| 285 | ACPI_RELEASE_GLOBAL_LOCK(acpi_gbl_FACS, pending); |
| 286 | |
| 287 | /* |
| 288 | * If the pending bit was set, we must write GBL_RLS to the control |
| 289 | * register |
| 290 | */ |
| 291 | if (pending) { |
| 292 | status = |
| 293 | acpi_write_bit_register |
| 294 | (ACPI_BITREG_GLOBAL_LOCK_RELEASE, |
| 295 | ACPI_ENABLE_EVENT); |
| 296 | } |
| 297 | |
| 298 | ACPI_DEBUG_PRINT((ACPI_DB_EXEC, |
| 299 | "Released hardware Global Lock\n")); |
| 300 | } |
| 301 | |
| 302 | acpi_gbl_global_lock_acquired = FALSE; |
| 303 | |
| 304 | /* Release the local GL mutex */ |
| 305 | |
| 306 | acpi_os_release_mutex(acpi_gbl_global_lock_mutex->mutex.os_mutex); |
| 307 | return_ACPI_STATUS(status); |
| 308 | } |
Bob Moore | 33620c5 | 2012-02-14 18:14:27 +0800 | [diff] [blame] | 309 | |
| 310 | #endif /* !ACPI_REDUCED_HARDWARE */ |