xref: /openbmc/linux/include/drm/drm_util.h (revision 04b3c795)
1 /*
2  * Internal Header for the Direct Rendering Manager
3  *
4  * Copyright 2018 Intel Corporation
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the "Software"),
8  * to deal in the Software without restriction, including without limitation
9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10  * and/or sell copies of the Software, and to permit persons to whom the
11  * Software is furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice (including the next
14  * paragraph) shall be included in all copies or substantial portions of the
15  * Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
20  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23  * OTHER DEALINGS IN THE SOFTWARE.
24  */
25 
26 #ifndef _DRM_UTIL_H_
27 #define _DRM_UTIL_H_
28 
29 /**
30  * DOC: drm utils
31  *
32  * Macros and inline functions that does not naturally belong in other places
33  */
34 
35 #include <linux/interrupt.h>
36 #include <linux/kgdb.h>
37 #include <linux/preempt.h>
38 #include <linux/smp.h>
39 
40 /*
41  * Use EXPORT_SYMBOL_FOR_TESTS_ONLY() for functions that shall
42  * only be visible for drmselftests.
43  */
44 #if defined(CONFIG_DRM_EXPORT_FOR_TESTS)
45 #define EXPORT_SYMBOL_FOR_TESTS_ONLY(x) EXPORT_SYMBOL(x)
46 #else
47 #define EXPORT_SYMBOL_FOR_TESTS_ONLY(x)
48 #endif
49 
50 /**
51  * for_each_if - helper for handling conditionals in various for_each macros
52  * @condition: The condition to check
53  *
54  * Typical use::
55  *
56  *	#define for_each_foo_bar(x, y) \'
57  *		list_for_each_entry(x, y->list, head) \'
58  *			for_each_if(x->something == SOMETHING)
59  *
60  * The for_each_if() macro makes the use of for_each_foo_bar() less error
61  * prone.
62  */
63 #define for_each_if(condition) if (!(condition)) {} else
64 
65 /**
66  * drm_can_sleep - returns true if currently okay to sleep
67  *
68  * This function shall not be used in new code.
69  * The check for running in atomic context may not work - see linux/preempt.h.
70  *
71  * FIXME: All users of drm_can_sleep should be removed (see todo.rst)
72  *
73  * Returns:
74  * False if kgdb is active, we are in atomic context or irqs are disabled.
75  */
76 static inline bool drm_can_sleep(void)
77 {
78 	if (in_atomic() || in_dbg_master() || irqs_disabled())
79 		return false;
80 	return true;
81 }
82 
83 #endif
84