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