2 * Copyright (C) 2014 Felix Fietkau <nbd@openwrt.org>
3 * Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2
7 * as published by the Free Software Foundation
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
19 * Power of two check, this will check
20 * if the mask that has been given contains and contiguous set of bits.
21 * Note that we cannot use the is_power_of_2() function since this
22 * check must be done at compile-time.
24 #define is_power_of_two(x) ( !((x) & ((x)-1)) )
25 #define low_bit_mask(x) ( ((x)-1) & ~(x) )
26 #define is_valid_mask(x) is_power_of_two(1LU + (x) + low_bit_mask(x))
29 * Macros to find first set bit in a variable.
30 * These macros behave the same as the __ffs() functions but
31 * the most important difference that this is done during
32 * compile-time rather then run-time.
34 #define compile_ffs2(__x) \
35 __builtin_choose_expr(((__x) & 0x1), 0, 1)
37 #define compile_ffs4(__x) \
38 __builtin_choose_expr(((__x) & 0x3), \
39 (compile_ffs2((__x))), \
40 (compile_ffs2((__x) >> 2) + 2))
42 #define compile_ffs8(__x) \
43 __builtin_choose_expr(((__x) & 0xf), \
44 (compile_ffs4((__x))), \
45 (compile_ffs4((__x) >> 4) + 4))
47 #define compile_ffs16(__x) \
48 __builtin_choose_expr(((__x) & 0xff), \
49 (compile_ffs8((__x))), \
50 (compile_ffs8((__x) >> 8) + 8))
52 #define compile_ffs32(__x) \
53 __builtin_choose_expr(((__x) & 0xffff), \
54 (compile_ffs16((__x))), \
55 (compile_ffs16((__x) >> 16) + 16))
58 * This macro will check the requirements for the FIELD{8,16,32} macros
59 * The mask should be a constant non-zero contiguous set of bits which
60 * does not exceed the given typelimit.
62 #define FIELD_CHECK(__mask) \
63 BUILD_BUG_ON(!(__mask) || !is_valid_mask(__mask))
65 #define MT76_SET(_mask, _val) \
68 (((u32) (_val)) << compile_ffs32(_mask)) & _mask; \
71 #define MT76_GET(_mask, _val) \
74 (u32) (((_val) & _mask) >> compile_ffs32(_mask)); \