| /* | |
| * Copyright (C) 2014 Felix Fietkau <nbd@openwrt.org> | |
| * Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com> | |
| * | |
| * This program is free software; you can redistribute it and/or modify | |
| * it under the terms of the GNU General Public License version 2 | |
| * as published by the Free Software Foundation | |
| * | |
| * This program is distributed in the hope that it will be useful, | |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| * GNU General Public License for more details. | |
| */ | |
| #ifndef __MT76_UTIL_H | |
| #define __MT76_UTIL_H | |
| /* | |
| * Power of two check, this will check | |
| * if the mask that has been given contains and contiguous set of bits. | |
| * Note that we cannot use the is_power_of_2() function since this | |
| * check must be done at compile-time. | |
| */ | |
| #define is_power_of_two(x) ( !((x) & ((x)-1)) ) | |
| #define low_bit_mask(x) ( ((x)-1) & ~(x) ) | |
| #define is_valid_mask(x) is_power_of_two(1LU + (x) + low_bit_mask(x)) | |
| /* | |
| * Macros to find first set bit in a variable. | |
| * These macros behave the same as the __ffs() functions but | |
| * the most important difference that this is done during | |
| * compile-time rather then run-time. | |
| */ | |
| #define compile_ffs2(__x) \ | |
| __builtin_choose_expr(((__x) & 0x1), 0, 1) | |
| #define compile_ffs4(__x) \ | |
| __builtin_choose_expr(((__x) & 0x3), \ | |
| (compile_ffs2((__x))), \ | |
| (compile_ffs2((__x) >> 2) + 2)) | |
| #define compile_ffs8(__x) \ | |
| __builtin_choose_expr(((__x) & 0xf), \ | |
| (compile_ffs4((__x))), \ | |
| (compile_ffs4((__x) >> 4) + 4)) | |
| #define compile_ffs16(__x) \ | |
| __builtin_choose_expr(((__x) & 0xff), \ | |
| (compile_ffs8((__x))), \ | |
| (compile_ffs8((__x) >> 8) + 8)) | |
| #define compile_ffs32(__x) \ | |
| __builtin_choose_expr(((__x) & 0xffff), \ | |
| (compile_ffs16((__x))), \ | |
| (compile_ffs16((__x) >> 16) + 16)) | |
| /* | |
| * This macro will check the requirements for the FIELD{8,16,32} macros | |
| * The mask should be a constant non-zero contiguous set of bits which | |
| * does not exceed the given typelimit. | |
| */ | |
| #define FIELD_CHECK(__mask) \ | |
| BUILD_BUG_ON(!(__mask) || !is_valid_mask(__mask)) | |
| #define MT76_SET(_mask, _val) \ | |
| ({ \ | |
| FIELD_CHECK(_mask); \ | |
| (((u32) (_val)) << compile_ffs32(_mask)) & _mask; \ | |
| }) | |
| #define MT76_GET(_mask, _val) \ | |
| ({ \ | |
| FIELD_CHECK(_mask); \ | |
| (u32) (((_val) & _mask) >> compile_ffs32(_mask)); \ | |
| }) | |
| #endif |