Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * include/asm-xtensa/bitops.h
3 *
4 * Atomic operations that C can't guarantee us.Useful for resource counting etc.
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 *
10 * Copyright (C) 2001 - 2007 Tensilica Inc.
11 */
12
13#ifndef _XTENSA_BITOPS_H
14#define _XTENSA_BITOPS_H
15
16#ifdef __KERNEL__
17
18#include <asm/processor.h>
19#include <asm/byteorder.h>
20#include <asm/system.h>
21
22#ifdef CONFIG_SMP
23# error SMP not supported on this architecture
24#endif
25
26#define smp_mb__before_clear_bit() barrier()
27#define smp_mb__after_clear_bit() barrier()
28
29#include <asm-generic/bitops/atomic.h>
30#include <asm-generic/bitops/non-atomic.h>
31
32#if XCHAL_HAVE_NSA
33
34static inline unsigned long __cntlz (unsigned long x)
35{
36 int lz;
37 asm ("nsau %0, %1" : "=r" (lz) : "r" (x));
38 return lz;
39}
40
41/*
42 * ffz: Find first zero in word. Undefined if no zero exists.
43 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
44 */
45
46static inline int ffz(unsigned long x)
47{
48 return 31 - __cntlz(~x & -~x);
49}
50
51/*
52 * __ffs: Find first bit set in word. Return 0 for bit 0
53 */
54
55static inline int __ffs(unsigned long x)
56{
57 return 31 - __cntlz(x & -x);
58}
59
60/*
61 * ffs: Find first bit set in word. This is defined the same way as
62 * the libc and compiler builtin ffs routines, therefore
63 * differs in spirit from the above ffz (man ffs).
64 */
65
66static inline int ffs(unsigned long x)
67{
68 return 32 - __cntlz(x & -x);
69}
70
71/*
72 * fls: Find last (most-significant) bit set in word.
73 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
74 */
75
76static inline int fls (unsigned int x)
77{
78 return 32 - __cntlz(x);
79}
80
81#else
82
83/* Use the generic implementation if we don't have the nsa/nsau instructions. */
84
85# include <asm-generic/bitops/ffs.h>
86# include <asm-generic/bitops/__ffs.h>
87# include <asm-generic/bitops/ffz.h>
88# include <asm-generic/bitops/fls.h>
89
90#endif
91
92#include <asm-generic/bitops/fls64.h>
93#include <asm-generic/bitops/find.h>
94#include <asm-generic/bitops/ext2-non-atomic.h>
95
96#ifdef __XTENSA_EL__
97# define ext2_set_bit_atomic(lock,nr,addr) \
98 test_and_set_bit((nr), (unsigned long*)(addr))
99# define ext2_clear_bit_atomic(lock,nr,addr) \
100 test_and_clear_bit((nr), (unsigned long*)(addr))
101#elif defined(__XTENSA_EB__)
102# define ext2_set_bit_atomic(lock,nr,addr) \
103 test_and_set_bit((nr) ^ 0x18, (unsigned long*)(addr))
104# define ext2_clear_bit_atomic(lock,nr,addr) \
105 test_and_clear_bit((nr) ^ 0x18, (unsigned long*)(addr))
106#else
107# error processor byte order undefined!
108#endif
109
110#include <asm-generic/bitops/hweight.h>
111#include <asm-generic/bitops/sched.h>
112#include <asm-generic/bitops/minix.h>
113
114#endif /* __KERNEL__ */
115
116#endif /* _XTENSA_BITOPS_H */