drm_atomic.h revision 302408 
1/**
2 * \file drm_atomic.h
3 * Atomic operations used in the DRM which may or may not be provided by the OS.
4 *
5 * \author Eric Anholt <anholt@FreeBSD.org>
6 */
7
8/*-
9 * Copyright 2004 Eric Anholt
10 * All Rights Reserved.
11 *
12 * Permission is hereby granted, free of charge, to any person obtaining a
13 * copy of this software and associated documentation files (the "Software"),
14 * to deal in the Software without restriction, including without limitation
15 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
16 * and/or sell copies of the Software, and to permit persons to whom the
17 * Software is furnished to do so, subject to the following conditions:
18 *
19 * The above copyright notice and this permission notice (including the next
20 * paragraph) shall be included in all copies or substantial portions of the
21 * Software.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
24 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
25 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
26 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
27 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
28 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
29 * OTHER DEALINGS IN THE SOFTWARE.
30 */
31
32#include <sys/cdefs.h>
33__FBSDID("$FreeBSD: stable/11/sys/dev/drm/drm_atomic.h 183573 2008-10-03 16:59:11Z rnoland $");
34
35/* Many of these implementations are rather fake, but good enough. */
36
37typedef u_int32_t atomic_t;
38
39#define atomic_set(p, v)	(*(p) = (v))
40#define atomic_read(p)		(*(p))
41#define atomic_inc(p)		atomic_add_int(p, 1)
42#define atomic_dec(p)		atomic_subtract_int(p, 1)
43#define atomic_add(n, p)	atomic_add_int(p, n)
44#define atomic_sub(n, p)	atomic_subtract_int(p, n)
45
46static __inline atomic_t
47test_and_set_bit(int b, volatile void *p)
48{
49	int s = splhigh();
50	unsigned int m = 1<<b;
51	unsigned int r = *(volatile int *)p & m;
52	*(volatile int *)p |= m;
53	splx(s);
54	return r;
55}
56
57static __inline void
58clear_bit(int b, volatile void *p)
59{
60	atomic_clear_int(((volatile int *)p) + (b >> 5), 1 << (b & 0x1f));
61}
62
63static __inline void
64set_bit(int b, volatile void *p)
65{
66	atomic_set_int(((volatile int *)p) + (b >> 5), 1 << (b & 0x1f));
67}
68
69static __inline int
70test_bit(int b, volatile void *p)
71{
72	return ((volatile int *)p)[b >> 5] & (1 << (b & 0x1f));
73}
74
75static __inline int
76find_first_zero_bit(volatile void *p, int max)
77{
78	int b;
79	volatile int *ptr = (volatile int *)p;
80
81	for (b = 0; b < max; b += 32) {
82		if (ptr[b >> 5] != ~0) {
83			for (;;) {
84				if ((ptr[b >> 5] & (1 << (b & 0x1f))) == 0)
85					return b;
86				b++;
87			}
88		}
89	}
90	return max;
91}
92