blob: df202e167ce487122e4440962eacb2e44817ad9f (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
|
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (C) 2025, Collabora Ltd.
*/
#ifndef _LINUX_HW_BITFIELD_H
#define _LINUX_HW_BITFIELD_H
#include <linux/bitfield.h>
#include <linux/build_bug.h>
#include <linux/limits.h>
/**
* FIELD_PREP_WM16() - prepare a bitfield element with a mask in the upper half
* @_mask: shifted mask defining the field's length and position
* @_val: value to put in the field
*
* FIELD_PREP_WM16() masks and shifts up the value, as well as bitwise ORs the
* result with the mask shifted up by 16.
*
* This is useful for a common design of hardware registers where the upper
* 16-bit half of a 32-bit register is used as a write-enable mask. In such a
* register, a bit in the lower half is only updated if the corresponding bit
* in the upper half is high.
*/
#define FIELD_PREP_WM16(_mask, _val) \
({ \
typeof(_val) __val = _val; \
typeof(_mask) __mask = _mask; \
__BF_FIELD_CHECK(__mask, ((u16)0U), __val, \
"HWORD_UPDATE: "); \
(((typeof(__mask))(__val) << __bf_shf(__mask)) & (__mask)) | \
((__mask) << 16); \
})
/**
* FIELD_PREP_WM16_CONST() - prepare a constant bitfield element with a mask in
* the upper half
* @_mask: shifted mask defining the field's length and position
* @_val: value to put in the field
*
* FIELD_PREP_WM16_CONST() masks and shifts up the value, as well as bitwise ORs
* the result with the mask shifted up by 16.
*
* This is useful for a common design of hardware registers where the upper
* 16-bit half of a 32-bit register is used as a write-enable mask. In such a
* register, a bit in the lower half is only updated if the corresponding bit
* in the upper half is high.
*
* Unlike FIELD_PREP_WM16(), this is a constant expression and can therefore
* be used in initializers. Error checking is less comfortable for this
* version.
*/
#define FIELD_PREP_WM16_CONST(_mask, _val) \
( \
FIELD_PREP_CONST(_mask, _val) | \
(BUILD_BUG_ON_ZERO(const_true((u64)(_mask) > U16_MAX)) + \
((_mask) << 16)) \
)
#endif /* _LINUX_HW_BITFIELD_H */
|
