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Diffstat (limited to 'include/linux/byteorder/bitfields.h')
| -rw-r--r-- | include/linux/byteorder/bitfields.h | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/include/linux/byteorder/bitfields.h b/include/linux/byteorder/bitfields.h new file mode 100644 index 000000000000..5a8c2f8a46b1 --- /dev/null +++ b/include/linux/byteorder/bitfields.h @@ -0,0 +1,114 @@ +/* + * Helpers for defining little-endian bitfields + * + * Copyright (C) 2007 Intel Corporation + * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.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. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#ifndef __LINUX__BYTEORDER__BITFIELDS_H__ +#define __LINUX__BYTEORDER__BITFIELDS_H__ + +#include <asm/byteorder.h> + +/* + * Declare Little Endian bitfields + * + * These macros are used to switch the order of the bitfields when + * packing with Little Endian in mind (ie: for mapping to a hw type + * that you have to send or read from a device). + * + * NOTE: When using multibyte bitfields, you need to convert the data + * from Little Endian to CPU before you can access the bitfield + * (to make it simpler): + * + * union something { + * le16 value; + * DECL_BF_LE3( + * u16 bf0:3, + * u16 bf1:10, + * u16 bf2:3 + * ) __attribute__((packed)); + * }; + * + * ... + * + * union something s; + * + * s.value = le16_to_cpu(something LE read from hw); + * frame_count = s.bf1; + * + */ +#ifdef __LITTLE_ENDIAN_BITFIELD +#define DECL_BF_LE2(a, b) struct { a; b; } +#define DECL_BF_LE3(a, b, c) struct { a; b; c; } +#define DECL_BF_LE4(a, b, c, d) struct { a; b; c; d ; } +#define DECL_BF_LE5(a, b, c, d, e) struct { a; b; c; d; e; } +#define DECL_BF_LE6(a, b, c, d, e, f) struct { a; b; c; d; e; f; } +#define DECL_BF_LE7(a, b, c, d, e, f, g) struct { a; b; c; d; e; f; g; } +#define DECL_BF_LE8(a, b, c, d, e, f, g, h) struct { a; b; c; d; e; f; g; h; } +#define DECL_BF_LE9(a, b, c, d, e, f, g, h, i) \ + struct { a; b; c; d; e; f; g; h; i; } +#define DECL_BF_LE10(a, b, c, d, e, f, g, h, i, j) \ + struct { a; b; c; d; e; f; g; h; i; j; } +#define DECL_BF_LE11(a, b, c, d, e, f, g, h, i, j, k) \ + struct { a; b; c; d; e; f; g; h; i; j; k; } +#define DECL_BF_LE12(a, b, c, d, e, f, g, h, i, j, k, l) \ + struct { a; b; c; d; e; f; g; h; i; j; k; l; } +#define DECL_BF_LE13(a, b, c, d, e, f, g, h, i, j, k, l, m) \ + struct { a; b; c; d; e; f; g; h; i; j; k; l; m; } +#define DECL_BF_LE14(a, b, c, d, e, f, g, h, i, j, k, l, m, n) \ + struct { a; b; c; d; e; f; g; h; i; j; k; l; m; n; } +#define DECL_BF_LE15(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) \ + struct { a; b; c; d; e; f; g; h; i; j; k; l; m; n; o; } +#define DECL_BF_LE16(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p) \ + struct { a; b; c; d; e; f; g; h; i; j; k; l; m; n; o; p; } + +#else +#ifdef __BIG_ENDIAN_BITFIELD + +#define DECL_BF_LE2(a, b) struct { b; a; } +#define DECL_BF_LE3(a, b, c) struct { c; b; a; } +#define DECL_BF_LE4(a, b, c, d) struct { d; c; b; a; } +#define DECL_BF_LE5(a, b, c, d, e) struct { e; d; c; b; a; } +#define DECL_BF_LE6(a, b, c, d, e, f) struct { f; e; d; c; b; a; } +#define DECL_BF_LE7(a, b, c, d, e, f, g) struct { g; f; e; d; c; b; a; } +#define DECL_BF_LE8(a, b, c, d, e, f, g, h) struct { h; g; f; e; d; c; b; a; } +#define DECL_BF_LE9(a, b, c, d, e, f, g, h, i) \ + struct { i; h; g; f; e; d; c; b; a; } +#define DECL_BF_LE10(a, b, c, d, e, f, g, h, i, j) \ + struct { j; i; h; g; f; e; d; c; b; a; } +#define DECL_BF_LE11(a, b, c, d, e, f, g, h, i, j, k) \ + struct { k; j; i; h; g; f; e; d; c; b; a; } +#define DECL_BF_LE12(a, b, c, d, e, f, g, h, i, j, k, l) \ + struct { l; k; j; i; h; g; f; e; d; c; b; a; } +#define DECL_BF_LE13(a, b, c, d, e, f, g, h, i, j, k, l, m) \ + struct { m; l; k; j; i; h; g; f; e; d; c; b; a; } +#define DECL_BF_LE14(a, b, c, d, e, f, g, h, i, j, k, l, m, n) \ + struct { n; m; l; k; j; i; h; g; f; e; d; c; b; a; } +#define DECL_BF_LE15(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) \ + struct { o; n; m; l; k; j; i; h; g; f; e; d; c; b; a; } +#define DECL_BF_LE16(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p) \ + struct { p; o; n; m; l; k; j; i; h; g; f; e; d; c; b; a; } + +#else + +#error Unknown endianess for Little Endian bitfield definition + +#endif +#endif + +#endif /* #ifndef __LINUX__BYTEORDER__BITFIELDS_H__ */ |