drm_atomic.h revision 145132 
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 * $FreeBSD: head/sys/dev/drm/drm_atomic.h 145132 2005-04-16 03:44:47Z anholt $
32 */
33
34/* Many of these implementations are rather fake, but good enough. */
35
36typedef u_int32_t atomic_t;
37
38#ifdef __FreeBSD__
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#else /* __FreeBSD__ */
46/* FIXME */
47#define atomic_set(p, v)	(*(p) = (v))
48#define atomic_read(p)		(*(p))
49#define atomic_inc(p)		(*(p) += 1)
50#define atomic_dec(p)		(*(p) -= 1)
51#define atomic_add(n, p)	(*(p) += (n))
52#define atomic_sub(n, p)	(*(p) -= (n))
53/* FIXME */
54#define atomic_add_int(p, v)      *(p) += v
55#define atomic_subtract_int(p, v) *(p) -= v
56#define atomic_set_int(p, bits)   *(p) |= (bits)
57#define atomic_clear_int(p, bits) *(p) &= ~(bits)
58#endif /* !__FreeBSD__ */
59
60#if !defined(__FreeBSD_version) || (__FreeBSD_version < 500000)
61#if defined(__i386__)
62/* The extra atomic functions from 5.0 haven't been merged to 4.x */
63static __inline int
64atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
65{
66	int res = exp;
67
68	__asm __volatile (
69	"	lock ;			"
70	"	cmpxchgl %1,%2 ;	"
71	"       setz	%%al ;		"
72	"	movzbl	%%al,%0 ;	"
73	"1:				"
74	"# atomic_cmpset_int"
75	: "+a" (res)			/* 0 (result) */
76	: "r" (src),			/* 1 */
77	  "m" (*(dst))			/* 2 */
78	: "memory");
79
80	return (res);
81}
82#else /* __i386__ */
83static __inline int
84atomic_cmpset_int(__volatile__ int *dst, int old, int new)
85{
86	int s = splhigh();
87	if (*dst==old) {
88		*dst = new;
89		splx(s);
90		return 1;
91	}
92	splx(s);
93	return 0;
94}
95#endif /* !__i386__ */
96#endif /* !__FreeBSD_version || __FreeBSD_version < 500000 */
97
98static __inline atomic_t
99test_and_set_bit(int b, volatile void *p)
100{
101	int s = splhigh();
102	unsigned int m = 1<<b;
103	unsigned int r = *(volatile int *)p & m;
104	*(volatile int *)p |= m;
105	splx(s);
106	return r;
107}
108
109static __inline void
110clear_bit(int b, volatile void *p)
111{
112	atomic_clear_int(((volatile int *)p) + (b >> 5), 1 << (b & 0x1f));
113}
114
115static __inline void
116set_bit(int b, volatile void *p)
117{
118	atomic_set_int(((volatile int *)p) + (b >> 5), 1 << (b & 0x1f));
119}
120
121static __inline int
122test_bit(int b, volatile void *p)
123{
124	return ((volatile int *)p)[b >> 5] & (1 << (b & 0x1f));
125}
126
127static __inline int
128find_first_zero_bit(volatile void *p, int max)
129{
130	int b;
131	volatile int *ptr = (volatile int *)p;
132
133	for (b = 0; b < max; b += 32) {
134		if (ptr[b >> 5] != ~0) {
135			for (;;) {
136				if ((ptr[b >> 5] & (1 << (b & 0x1f))) == 0)
137					return b;
138				b++;
139			}
140		}
141	}
142	return max;
143}
144