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("$FreeBSD$"); 34 35 /* Many of these implementations are rather fake, but good enough. */ 36 37 typedef 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 46 static __inline atomic_t 47 test_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 57 static __inline void 58 clear_bit(int b, volatile void *p) 59 { 60 atomic_clear_int(((volatile int *)p) + (b >> 5), 1 << (b & 0x1f)); 61 } 62 63 static __inline void 64 set_bit(int b, volatile void *p) 65 { 66 atomic_set_int(((volatile int *)p) + (b >> 5), 1 << (b & 0x1f)); 67 } 68 69 static __inline int 70 test_bit(int b, volatile void *p) 71 { 72 return ((volatile int *)p)[b >> 5] & (1 << (b & 0x1f)); 73 } 74 75 static __inline int 76 find_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 93 #define BITS_TO_LONGS(x) (howmany((x), NBBY * sizeof(long))) 94