| /** |
| * \file drm_atomic.h |
| * Atomic operations used in the DRM which may or may not be provided by the OS. |
| * |
| * \author Eric Anholt <anholt@FreeBSD.org> |
| */ |
| |
| /*- |
| * Copyright 2004 Eric Anholt |
| * All Rights Reserved. |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the "Software"), |
| * to deal in the Software without restriction, including without limitation |
| * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| * and/or sell copies of the Software, and to permit persons to whom the |
| * Software is furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice (including the next |
| * paragraph) shall be included in all copies or substantial portions of the |
| * Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR |
| * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, |
| * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR |
| * OTHER DEALINGS IN THE SOFTWARE. |
| */ |
| |
| /* Many of these implementations are rather fake, but good enough. */ |
| |
| typedef u_int32_t atomic_t; |
| |
| #ifdef __FreeBSD__ |
| #define atomic_set(p, v) (*(p) = (v)) |
| #define atomic_read(p) (*(p)) |
| #define atomic_inc(p) atomic_add_int(p, 1) |
| #define atomic_dec(p) atomic_subtract_int(p, 1) |
| #define atomic_add(n, p) atomic_add_int(p, n) |
| #define atomic_sub(n, p) atomic_subtract_int(p, n) |
| #else /* __FreeBSD__ */ |
| /* FIXME */ |
| #define atomic_set(p, v) (*(p) = (v)) |
| #define atomic_read(p) (*(p)) |
| #define atomic_inc(p) (*(p) += 1) |
| #define atomic_dec(p) (*(p) -= 1) |
| #define atomic_add(n, p) (*(p) += (n)) |
| #define atomic_sub(n, p) (*(p) -= (n)) |
| /* FIXME */ |
| #define atomic_add_int(p, v) *(p) += v |
| #define atomic_subtract_int(p, v) *(p) -= v |
| #define atomic_set_int(p, bits) *(p) |= (bits) |
| #define atomic_clear_int(p, bits) *(p) &= ~(bits) |
| #endif /* !__FreeBSD__ */ |
| |
| #if !defined(__FreeBSD_version) || (__FreeBSD_version < 500000) |
| #if defined(__i386__) |
| /* The extra atomic functions from 5.0 haven't been merged to 4.x */ |
| static __inline int |
| atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) |
| { |
| int res = exp; |
| |
| __asm __volatile ( |
| " lock ; " |
| " cmpxchgl %1,%2 ; " |
| " setz %%al ; " |
| " movzbl %%al,%0 ; " |
| "1: " |
| "# atomic_cmpset_int" |
| : "+a" (res) /* 0 (result) */ |
| : "r" (src), /* 1 */ |
| "m" (*(dst)) /* 2 */ |
| : "memory"); |
| |
| return (res); |
| } |
| #else /* __i386__ */ |
| static __inline int |
| atomic_cmpset_int(__volatile__ int *dst, int old, int new) |
| { |
| int s = splhigh(); |
| if (*dst==old) { |
| *dst = new; |
| splx(s); |
| return 1; |
| } |
| splx(s); |
| return 0; |
| } |
| #endif /* !__i386__ */ |
| #endif /* !__FreeBSD_version || __FreeBSD_version < 500000 */ |
| |
| static __inline atomic_t |
| test_and_set_bit(int b, volatile void *p) |
| { |
| int s = splhigh(); |
| unsigned int m = 1<<b; |
| unsigned int r = *(volatile int *)p & m; |
| *(volatile int *)p |= m; |
| splx(s); |
| return r; |
| } |
| |
| static __inline void |
| clear_bit(int b, volatile void *p) |
| { |
| atomic_clear_int(((volatile int *)p) + (b >> 5), 1 << (b & 0x1f)); |
| } |
| |
| static __inline void |
| set_bit(int b, volatile void *p) |
| { |
| atomic_set_int(((volatile int *)p) + (b >> 5), 1 << (b & 0x1f)); |
| } |
| |
| static __inline int |
| test_bit(int b, volatile void *p) |
| { |
| return ((volatile int *)p)[b >> 5] & (1 << (b & 0x1f)); |
| } |
| |
| static __inline int |
| find_first_zero_bit(volatile void *p, int max) |
| { |
| int b; |
| volatile int *ptr = (volatile int *)p; |
| |
| for (b = 0; b < max; b += 32) { |
| if (ptr[b >> 5] != ~0) { |
| for (;;) { |
| if ((ptr[b >> 5] & (1 << (b & 0x1f))) == 0) |
| return b; |
| b++; |
| } |
| } |
| } |
| return max; |
| } |