1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
4  * Module Name: evglock - Global Lock support
6  * Copyright (C) 2000 - 2023, Intel Corp.
27  * RETURN:      Status
29  * DESCRIPTION: Install a handler for the global lock release event
35 	acpi_status status;  in acpi_ev_init_global_lock_handler()  local
39 	/* If Hardware Reduced flag is set, there is no global lock */  in acpi_ev_init_global_lock_handler()
45 	/* Attempt installation of the global lock handler */  in acpi_ev_init_global_lock_handler()
47 	status = acpi_install_fixed_event_handler(ACPI_EVENT_GLOBAL,  in acpi_ev_init_global_lock_handler()
52 	 * If the global lock does not exist on this platform, the attempt to  in acpi_ev_init_global_lock_handler()
54 	 * Map to AE_OK, but mark global lock as not present. Any attempt to  in acpi_ev_init_global_lock_handler()
55 	 * actually use the global lock will be flagged with an error.  in acpi_ev_init_global_lock_handler()
58 	if (status == AE_NO_HARDWARE_RESPONSE) {  in acpi_ev_init_global_lock_handler()
60 			    "No response from Global Lock hardware, disabling lock"));  in acpi_ev_init_global_lock_handler()
65 	status = acpi_os_create_lock(&acpi_gbl_global_lock_pending_lock);  in acpi_ev_init_global_lock_handler()
66 	if (ACPI_FAILURE(status)) {  in acpi_ev_init_global_lock_handler()
67 		return_ACPI_STATUS(status);  in acpi_ev_init_global_lock_handler()
72 	return_ACPI_STATUS(status);  in acpi_ev_init_global_lock_handler()
81  * RETURN:      Status
83  * DESCRIPTION: Remove the handler for the Global Lock
89 	acpi_status status;  in acpi_ev_remove_global_lock_handler()  local
94 	status = acpi_remove_fixed_event_handler(ACPI_EVENT_GLOBAL,  in acpi_ev_remove_global_lock_handler()
98 	return_ACPI_STATUS(status);  in acpi_ev_remove_global_lock_handler()
105  * PARAMETERS:  context         - From thread interface, not used
109  * DESCRIPTION: Invoked directly from the SCI handler when a global lock
111  *              request for the lock, signal the waiting thread.
117 	acpi_status status;  in acpi_ev_global_lock_handler()  local
123 	 * If a request for the global lock is not actually pending,  in acpi_ev_global_lock_handler()
124 	 * we are done. This handles "spurious" global lock interrupts  in acpi_ev_global_lock_handler()
132 	 * Send a unit to the global lock semaphore. The actual acquisition  in acpi_ev_global_lock_handler()
133 	 * of the global lock will be performed by the waiting thread.  in acpi_ev_global_lock_handler()
135 	status = acpi_os_signal_semaphore(acpi_gbl_global_lock_semaphore, 1);  in acpi_ev_global_lock_handler()
136 	if (ACPI_FAILURE(status)) {  in acpi_ev_global_lock_handler()
137 		ACPI_ERROR((AE_INFO, "Could not signal Global Lock semaphore"));  in acpi_ev_global_lock_handler()
152  * PARAMETERS:  timeout         - Max time to wait for the lock, in millisec.
154  * RETURN:      Status
156  * DESCRIPTION: Attempt to gain ownership of the Global Lock.
161  * Global Lock, and the OS would hold the lock until the last thread had
163  * lock, especially in the case where there is a tight handshake between the
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.
173 	acpi_status status;  in acpi_ev_acquire_global_lock()  local
182 	status =  in acpi_ev_acquire_global_lock()
183 	    acpi_ex_system_wait_mutex(acpi_gbl_global_lock_mutex->mutex.  in acpi_ev_acquire_global_lock()
185 	if (ACPI_FAILURE(status)) {  in acpi_ev_acquire_global_lock()
186 		return_ACPI_STATUS(status);  in acpi_ev_acquire_global_lock()
190 	 * Update the global lock handle and check for wraparound. The handle is  in acpi_ev_acquire_global_lock()
191 	 * only used for the external global lock interfaces, but it is updated  in acpi_ev_acquire_global_lock()
193 	 * lock via both the AML and the acpi_acquire_global_lock interfaces. The  in acpi_ev_acquire_global_lock()
203 	 * Make sure that a global lock actually exists. If not, just  in acpi_ev_acquire_global_lock()
204 	 * treat the lock as a standard mutex.  in acpi_ev_acquire_global_lock()
215 		/* Attempt to acquire the actual hardware lock */  in acpi_ev_acquire_global_lock()
221 					  "Acquired hardware Global Lock\n"));  in acpi_ev_acquire_global_lock()
226 		 * Did not get the lock. The pending bit was set above, and  in acpi_ev_acquire_global_lock()
227 		 * we must now wait until we receive the global lock  in acpi_ev_acquire_global_lock()
234 				  "Waiting for hardware Global Lock\n"));  in acpi_ev_acquire_global_lock()
237 		 * Wait for handshake with the global lock interrupt handler.  in acpi_ev_acquire_global_lock()
240 		status =  in acpi_ev_acquire_global_lock()
246 	} while (ACPI_SUCCESS(status));  in acpi_ev_acquire_global_lock()
251 	return_ACPI_STATUS(status);  in acpi_ev_acquire_global_lock()
260  * RETURN:      Status
262  * DESCRIPTION: Releases ownership of the Global Lock.
269 	acpi_status status = AE_OK;  in acpi_ev_release_global_lock()  local
273 	/* Lock must be already acquired */  in acpi_ev_release_global_lock()
277 			      "Cannot release the ACPI Global Lock, it has not been acquired"));  in acpi_ev_release_global_lock()
283 		/* Allow any thread to release the lock */  in acpi_ev_release_global_lock()
292 			status =  in acpi_ev_release_global_lock()
299 				  "Released hardware Global Lock\n"));  in acpi_ev_release_global_lock()
306 	acpi_os_release_mutex(acpi_gbl_global_lock_mutex->mutex.os_mutex);  in acpi_ev_release_global_lock()
307 	return_ACPI_STATUS(status);  in acpi_ev_release_global_lock()