xref: /openbmc/linux/drivers/acpi/acpica/exsystem.c (revision 9a29f5fc)
1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2 /******************************************************************************
3  *
4  * Module Name: exsystem - Interface to OS services
5  *
6  * Copyright (C) 2000 - 2022, Intel Corp.
7  *
8  *****************************************************************************/
9 
10 #include <acpi/acpi.h>
11 #include "accommon.h"
12 #include "acinterp.h"
13 
14 #define _COMPONENT          ACPI_EXECUTER
15 ACPI_MODULE_NAME("exsystem")
16 
17 /*******************************************************************************
18  *
19  * FUNCTION:    acpi_ex_system_wait_semaphore
20  *
21  * PARAMETERS:  semaphore       - Semaphore to wait on
22  *              timeout         - Max time to wait
23  *
24  * RETURN:      Status
25  *
26  * DESCRIPTION: Implements a semaphore wait with a check to see if the
27  *              semaphore is available immediately. If it is not, the
28  *              interpreter is released before waiting.
29  *
30  ******************************************************************************/
31 acpi_status acpi_ex_system_wait_semaphore(acpi_semaphore semaphore, u16 timeout)
32 {
33 	acpi_status status;
34 
35 	ACPI_FUNCTION_TRACE(ex_system_wait_semaphore);
36 
37 	status = acpi_os_wait_semaphore(semaphore, 1, ACPI_DO_NOT_WAIT);
38 	if (ACPI_SUCCESS(status)) {
39 		return_ACPI_STATUS(status);
40 	}
41 
42 	if (status == AE_TIME) {
43 
44 		/* We must wait, so unlock the interpreter */
45 
46 		acpi_ex_exit_interpreter();
47 		status = acpi_os_wait_semaphore(semaphore, 1, timeout);
48 
49 		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
50 				  "*** Thread awake after blocking, %s\n",
51 				  acpi_format_exception(status)));
52 
53 		/* Reacquire the interpreter */
54 
55 		acpi_ex_enter_interpreter();
56 	}
57 
58 	return_ACPI_STATUS(status);
59 }
60 
61 /*******************************************************************************
62  *
63  * FUNCTION:    acpi_ex_system_wait_mutex
64  *
65  * PARAMETERS:  mutex           - Mutex to wait on
66  *              timeout         - Max time to wait
67  *
68  * RETURN:      Status
69  *
70  * DESCRIPTION: Implements a mutex wait with a check to see if the
71  *              mutex is available immediately. If it is not, the
72  *              interpreter is released before waiting.
73  *
74  ******************************************************************************/
75 
76 acpi_status acpi_ex_system_wait_mutex(acpi_mutex mutex, u16 timeout)
77 {
78 	acpi_status status;
79 
80 	ACPI_FUNCTION_TRACE(ex_system_wait_mutex);
81 
82 	status = acpi_os_acquire_mutex(mutex, ACPI_DO_NOT_WAIT);
83 	if (ACPI_SUCCESS(status)) {
84 		return_ACPI_STATUS(status);
85 	}
86 
87 	if (status == AE_TIME) {
88 
89 		/* We must wait, so unlock the interpreter */
90 
91 		acpi_ex_exit_interpreter();
92 		status = acpi_os_acquire_mutex(mutex, timeout);
93 
94 		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
95 				  "*** Thread awake after blocking, %s\n",
96 				  acpi_format_exception(status)));
97 
98 		/* Reacquire the interpreter */
99 
100 		acpi_ex_enter_interpreter();
101 	}
102 
103 	return_ACPI_STATUS(status);
104 }
105 
106 /*******************************************************************************
107  *
108  * FUNCTION:    acpi_ex_system_do_stall
109  *
110  * PARAMETERS:  how_long_us     - The amount of time to stall,
111  *                                in microseconds
112  *
113  * RETURN:      Status
114  *
115  * DESCRIPTION: Suspend running thread for specified amount of time.
116  *              Note: ACPI specification requires that Stall() does not
117  *              relinquish the processor, and delays longer than 100 usec
118  *              should use Sleep() instead. We allow stalls up to 255 usec
119  *              for compatibility with other interpreters and existing BIOSs.
120  *
121  ******************************************************************************/
122 
123 acpi_status acpi_ex_system_do_stall(u32 how_long_us)
124 {
125 	acpi_status status = AE_OK;
126 
127 	ACPI_FUNCTION_ENTRY();
128 
129 	if (how_long_us > 255) {
130 		/*
131 		 * Longer than 255 microseconds, this is an error
132 		 *
133 		 * (ACPI specifies 100 usec as max, but this gives some slack in
134 		 * order to support existing BIOSs)
135 		 */
136 		ACPI_ERROR((AE_INFO,
137 			    "Time parameter is too large (%u)", how_long_us));
138 		status = AE_AML_OPERAND_VALUE;
139 	} else {
140 		if (how_long_us > 100) {
141 			ACPI_WARNING((AE_INFO,
142 				      "Time parameter %u us > 100 us violating ACPI spec, please fix the firmware.",
143 				      how_long_us));
144 		}
145 		acpi_os_stall(how_long_us);
146 	}
147 
148 	return (status);
149 }
150 
151 /*******************************************************************************
152  *
153  * FUNCTION:    acpi_ex_system_do_sleep
154  *
155  * PARAMETERS:  how_long_ms     - The amount of time to sleep,
156  *                                in milliseconds
157  *
158  * RETURN:      None
159  *
160  * DESCRIPTION: Sleep the running thread for specified amount of time.
161  *
162  ******************************************************************************/
163 
164 acpi_status acpi_ex_system_do_sleep(u64 how_long_ms)
165 {
166 	ACPI_FUNCTION_ENTRY();
167 
168 	/* Since this thread will sleep, we must release the interpreter */
169 
170 	acpi_ex_exit_interpreter();
171 
172 	/*
173 	 * For compatibility with other ACPI implementations and to prevent
174 	 * accidental deep sleeps, limit the sleep time to something reasonable.
175 	 */
176 	if (how_long_ms > ACPI_MAX_SLEEP) {
177 		how_long_ms = ACPI_MAX_SLEEP;
178 	}
179 
180 	acpi_os_sleep(how_long_ms);
181 
182 	/* And now we must get the interpreter again */
183 
184 	acpi_ex_enter_interpreter();
185 	return (AE_OK);
186 }
187 
188 /*******************************************************************************
189  *
190  * FUNCTION:    acpi_ex_system_signal_event
191  *
192  * PARAMETERS:  obj_desc        - The object descriptor for this op
193  *
194  * RETURN:      Status
195  *
196  * DESCRIPTION: Provides an access point to perform synchronization operations
197  *              within the AML.
198  *
199  ******************************************************************************/
200 
201 acpi_status acpi_ex_system_signal_event(union acpi_operand_object * obj_desc)
202 {
203 	acpi_status status = AE_OK;
204 
205 	ACPI_FUNCTION_TRACE(ex_system_signal_event);
206 
207 	if (obj_desc) {
208 		status =
209 		    acpi_os_signal_semaphore(obj_desc->event.os_semaphore, 1);
210 	}
211 
212 	return_ACPI_STATUS(status);
213 }
214 
215 /*******************************************************************************
216  *
217  * FUNCTION:    acpi_ex_system_wait_event
218  *
219  * PARAMETERS:  time_desc       - The 'time to delay' object descriptor
220  *              obj_desc        - The object descriptor for this op
221  *
222  * RETURN:      Status
223  *
224  * DESCRIPTION: Provides an access point to perform synchronization operations
225  *              within the AML. This operation is a request to wait for an
226  *              event.
227  *
228  ******************************************************************************/
229 
230 acpi_status
231 acpi_ex_system_wait_event(union acpi_operand_object *time_desc,
232 			  union acpi_operand_object *obj_desc)
233 {
234 	acpi_status status = AE_OK;
235 
236 	ACPI_FUNCTION_TRACE(ex_system_wait_event);
237 
238 	if (obj_desc) {
239 		status =
240 		    acpi_ex_system_wait_semaphore(obj_desc->event.os_semaphore,
241 						  (u16) time_desc->integer.
242 						  value);
243 	}
244 
245 	return_ACPI_STATUS(status);
246 }
247 
248 /*******************************************************************************
249  *
250  * FUNCTION:    acpi_ex_system_reset_event
251  *
252  * PARAMETERS:  obj_desc        - The object descriptor for this op
253  *
254  * RETURN:      Status
255  *
256  * DESCRIPTION: Reset an event to a known state.
257  *
258  ******************************************************************************/
259 
260 acpi_status acpi_ex_system_reset_event(union acpi_operand_object *obj_desc)
261 {
262 	acpi_status status = AE_OK;
263 	acpi_semaphore temp_semaphore;
264 
265 	ACPI_FUNCTION_ENTRY();
266 
267 	/*
268 	 * We are going to simply delete the existing semaphore and
269 	 * create a new one!
270 	 */
271 	status =
272 	    acpi_os_create_semaphore(ACPI_NO_UNIT_LIMIT, 0, &temp_semaphore);
273 	if (ACPI_SUCCESS(status)) {
274 		(void)acpi_os_delete_semaphore(obj_desc->event.os_semaphore);
275 		obj_desc->event.os_semaphore = temp_semaphore;
276 	}
277 
278 	return (status);
279 }
280