sys/external/bsd/drm/dist/bsd-core/drm_atomic.h

   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 /* Many of these implementations are rather fake, but good enough. */
  33
  34 typedef u_int32_t atomic_t;
  35
  36 #if defined(__FreeBSD__)
  37 #define atomic_set(p, v)        (*(p) = (v))
  38 #define atomic_read(p)          (*(p))
  39 #define atomic_inc(p)           atomic_add_int(p, 1)
  40 #define atomic_dec(p)           atomic_subtract_int(p, 1)
  41 #define atomic_add(n, p)        atomic_add_int(p, n)
  42 #define atomic_sub(n, p)        atomic_subtract_int(p, n)
  43
  44 static __inline atomic_t
  45 test_and_set_bit(int b, volatile void *p)
  46 {
  47         int s = splhigh();
  48         unsigned int m = 1<<b;
  49         unsigned int r = *(volatile int *)p & m;
  50         *(volatile int *)p |= m;
  51         splx(s);
  52         return r;
  53 }
  54
  55 static __inline void
  56 clear_bit(int b, volatile void *p)
  57 {
  58         atomic_clear_int(((volatile int *)p) + (b >> 5), 1 << (b & 0x1f));
  59 }
  60
  61 static __inline void
  62 set_bit(int b, volatile void *p)
  63 {
  64         atomic_set_int(((volatile int *)p) + (b >> 5), 1 << (b & 0x1f));
  65 }
  66
  67 static __inline int
  68 test_bit(int b, volatile void *p)
  69 {
  70         return ((volatile int *)p)[b >> 5] & (1 << (b & 0x1f));
  71 }
  72
  73 #elif   defined(__NetBSD__)
  74
  75 #include <sys/atomic.h>
  76
  77 #define atomic_set(p, v)                (*((volatile uint32_t *)p) = (v))
  78 #define atomic_read(p)          (*(p))
  79 #define atomic_inc(p)           atomic_inc_uint(p)
  80 #define atomic_dec(p)           atomic_dec_uint(p)
  81 #define atomic_add(n, p)        atomic_add_int(p, n)
  82 #define atomic_sub(n, p)        atomic_add_int(p, -(n))
  83
  84 #define atomic_add_acq_int(p, v)        atomic_add(v, p)
  85 #define atomic_subtract_acq_int(p, v)   atomic_sub(v, p)
  86 #define atomic_set_int(p, bits)         atomic_or_uint(p, bits)
  87 #define atomic_clear_int(p, bits)       atomic_and_uint(p, ~(bits))
  88
  89 #define atomic_cmpset_int(p, o, n)                                      \
  90                         ((old == atomic_cas_uint(p, o, n)) ? 1 : 0)
  91
  92 #define set_bit(b, p)                                                   \
  93         atomic_set_int(((volatile uint32_t *)(volatile void *)p) + (b >> 5),\
  94                         (1 << (b & 0x1f)))
  95
  96 #define clear_bit(b, p)                                                 \
  97         atomic_clear_int(((volatile uint32_t *)(volatile void *)p) + (b >> 5), \
  98                         (1 << (b & 0x1f)))
  99
 100 #define test_bit(b, p)                                                  \
 101         (((volatile uint32_t *)(volatile void *)p)[b >> 5] & (1 << (b & 0x1f)))
 102
 103 static __inline uint32_t
 104 test_and_set_bit(int b, volatile void *p)
 105 {
 106         volatile uint32_t *val;
 107         uint32_t mask, old;
 108
 109         val = (volatile uint32_t *)p;
 110         mask = 1 << b;
 111
 112         do {
 113                 old = *val;
 114                 if ((old & mask) != 0)
 115                         break;
 116         } while (atomic_cas_uint(val, old, old | mask) != old);
 117
 118         return old & mask;
 119 }
 120
 121 #endif
 122 static __inline int
 123 find_first_zero_bit(volatile void *p, int max_)
 124 {
 125         int b;
 126         volatile int *ptr = (volatile int *)p;
 127
 128         for (b = 0; b < max_; b += 32) {
 129                 if (ptr[b >> 5] != ~0) {
 130                         for (;;) {
 131                                 if ((ptr[b >> 5] & (1 << (b & 0x1f))) == 0)
 132                                         return b;
 133                                 b++;
 134                         }
 135                 }
 136         }
 137         return max_;
 138 }