projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| c869f77d JK |
1 | /* |
| 2 | * Copyright (C) 2014 Felix Fietkau <nbd@openwrt.org> | |
| 3 | * Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com> | |
| 4 | * | |
| 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 | |
| 8 | * | |
| 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. | |
| 13 | */ | |
| 14 | ||
| 15 | #ifndef __MT76_UTIL_H | |
| 16 | #define __MT76_UTIL_H | |
| 17 | ||
| 18 | /* | |
| 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. | |
| 23 | */ | |
| 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)) | |
| 27 | ||
| 28 | /* | |
| 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. | |
| 33 | */ | |
| 34 | #define compile_ffs2(__x) \ | |
| 35 | __builtin_choose_expr(((__x) & 0x1), 0, 1) | |
| 36 | ||
| 37 | #define compile_ffs4(__x) \ | |
| 38 | __builtin_choose_expr(((__x) & 0x3), \ | |
| 39 | (compile_ffs2((__x))), \ | |
| 40 | (compile_ffs2((__x) >> 2) + 2)) | |
| 41 | ||
| 42 | #define compile_ffs8(__x) \ | |
| 43 | __builtin_choose_expr(((__x) & 0xf), \ | |
| 44 | (compile_ffs4((__x))), \ | |
| 45 | (compile_ffs4((__x) >> 4) + 4)) | |
| 46 | ||
| 47 | #define compile_ffs16(__x) \ | |
| 48 | __builtin_choose_expr(((__x) & 0xff), \ | |
| 49 | (compile_ffs8((__x))), \ | |
| 50 | (compile_ffs8((__x) >> 8) + 8)) | |
| 51 | ||
| 52 | #define compile_ffs32(__x) \ | |
| 53 | __builtin_choose_expr(((__x) & 0xffff), \ | |
| 54 | (compile_ffs16((__x))), \ | |
| 55 | (compile_ffs16((__x) >> 16) + 16)) | |
| 56 | ||
| 57 | /* | |
| 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. | |
| 61 | */ | |
| 62 | #define FIELD_CHECK(__mask) \ | |
| 63 | BUILD_BUG_ON(!(__mask) || !is_valid_mask(__mask)) | |
| 64 | ||
| 65 | #define MT76_SET(_mask, _val) \ | |
| 66 | ({ \ | |
| 67 | FIELD_CHECK(_mask); \ | |
| 68 | (((u32) (_val)) << compile_ffs32(_mask)) & _mask; \ | |
| 69 | }) | |
| 70 | ||
| 71 | #define MT76_GET(_mask, _val) \ | |
| 72 | ({ \ | |
| 73 | FIELD_CHECK(_mask); \ | |
| 74 | (u32) (((_val) & _mask) >> compile_ffs32(_mask)); \ | |
| 75 | }) | |
| 76 | ||
| 77 | #endif |