Greg Kroah-Hartman
598cf27219
Link: https://lore.kernel.org/r/20260217200002.683975158@linuxfoundation.org Tested-by: Florian Fainelli <florian.fainelli@broadcom.com> Tested-by: Takeshi Ogasawara <takeshi.ogasawara@futuring-girl.com> Tested-by: Peter Schneider <pschneider1968@googlemail.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Salvatore Bonaccorso <carnil@debian.org> Tested-by: Brett A C Sheffield <bacs@librecast.net> Tested-by: Mark Brown <broonie@kernel.org> Tested-by: Luna Jernberg <droidbittin@gmail.com> Tested-by: Ronald Warsow <rwarsow@gmx.de> Tested-by: Justin M. Forbes <jforbes@fedoraproject.org> Tested-by: Ron Economos <re@w6rz.net> Tested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
63 lines
2.1 KiB
C
63 lines
2.1 KiB
C
/* 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 */
|