linux/include/drm/intel/reg_bits.h

140 lines
5.7 KiB
C

/* SPDX-License-Identifier: MIT */
/* Copyright © 2026 Intel Corporation */
#ifndef _REG_BITS_H_
#define _REG_BITS_H_
#include <linux/bitfield.h>
#include <linux/bits.h>
/*
* Wrappers over the generic fixed width BIT_U*() and GENMASK_U*()
* implementations, for compatibility reasons with previous implementation.
*/
#define REG_GENMASK(high, low) GENMASK_U32(high, low)
#define REG_GENMASK64(high, low) GENMASK_U64(high, low)
#define REG_GENMASK16(high, low) GENMASK_U16(high, low)
#define REG_GENMASK8(high, low) GENMASK_U8(high, low)
#define REG_BIT(n) BIT_U32(n)
#define REG_BIT64(n) BIT_U64(n)
#define REG_BIT16(n) BIT_U16(n)
#define REG_BIT8(n) BIT_U8(n)
/*
* Local integer constant expression version of is_power_of_2().
*/
#define IS_POWER_OF_2(__x) ((__x) && (((__x) & ((__x) - 1)) == 0))
/**
* REG_FIELD_PREP8() - Prepare a u8 bitfield value
* @__mask: shifted mask defining the field's length and position
* @__val: value to put in the field
*
* Local copy of FIELD_PREP() to generate an integer constant expression, force
* u8 and for consistency with REG_FIELD_GET8(), REG_BIT8() and REG_GENMASK8().
*
* @return: @__val masked and shifted into the field defined by @__mask.
*/
#define REG_FIELD_PREP8(__mask, __val) \
((u8)((((typeof(__mask))(__val) << __bf_shf(__mask)) & (__mask)) + \
BUILD_BUG_ON_ZERO(!__is_constexpr(__mask)) + \
BUILD_BUG_ON_ZERO((__mask) == 0 || (__mask) > U8_MAX) + \
BUILD_BUG_ON_ZERO(!IS_POWER_OF_2((__mask) + (1ULL << __bf_shf(__mask)))) + \
BUILD_BUG_ON_ZERO(__builtin_choose_expr(__is_constexpr(__val), (~((__mask) >> __bf_shf(__mask)) & (__val)), 0))))
/**
* REG_FIELD_PREP16() - Prepare a u16 bitfield value
* @__mask: shifted mask defining the field's length and position
* @__val: value to put in the field
*
* Local copy of FIELD_PREP16() to generate an integer constant
* expression, force u8 and for consistency with
* REG_FIELD_GET16(), REG_BIT16() and REG_GENMASK16().
*
* @return: @__val masked and shifted into the field defined by @__mask.
*/
#define REG_FIELD_PREP16(__mask, __val) \
((u16)((((typeof(__mask))(__val) << __bf_shf(__mask)) & (__mask)) + \
BUILD_BUG_ON_ZERO(!__is_constexpr(__mask)) + \
BUILD_BUG_ON_ZERO((__mask) == 0 || (__mask) > U16_MAX) + \
BUILD_BUG_ON_ZERO(!IS_POWER_OF_2((__mask) + (1ULL << __bf_shf(__mask)))) + \
BUILD_BUG_ON_ZERO(__builtin_choose_expr(__is_constexpr(__val), (~((__mask) >> __bf_shf(__mask)) & (__val)), 0))))
/**
* REG_FIELD_PREP() - Prepare a u32 bitfield value
* @__mask: shifted mask defining the field's length and position
* @__val: value to put in the field
*
* Local copy of FIELD_PREP() to generate an integer constant expression, force
* u32 and for consistency with REG_FIELD_GET(), REG_BIT() and REG_GENMASK().
*
* @return: @__val masked and shifted into the field defined by @__mask.
*/
#define REG_FIELD_PREP(__mask, __val) \
((u32)((((typeof(__mask))(__val) << __bf_shf(__mask)) & (__mask)) + \
BUILD_BUG_ON_ZERO(!__is_constexpr(__mask)) + \
BUILD_BUG_ON_ZERO((__mask) == 0 || (__mask) > U32_MAX) + \
BUILD_BUG_ON_ZERO(!IS_POWER_OF_2((__mask) + (1ULL << __bf_shf(__mask)))) + \
BUILD_BUG_ON_ZERO(__builtin_choose_expr(__is_constexpr(__val), (~((__mask) >> __bf_shf(__mask)) & (__val)), 0))))
/**
* REG_FIELD_GET8() - Extract a u8 bitfield value
* @__mask: shifted mask defining the field's length and position
* @__val: value to extract the bitfield value from
*
* Local wrapper for FIELD_GET() to force u8 and for consistency with
* REG_FIELD_PREP(), REG_BIT() and REG_GENMASK().
*
* @return: Masked and shifted value of the field defined by @__mask in @__val.
*/
#define REG_FIELD_GET8(__mask, __val) ((u8)FIELD_GET(__mask, __val))
/**
* REG_FIELD_GET() - Extract a u32 bitfield value
* @__mask: shifted mask defining the field's length and position
* @__val: value to extract the bitfield value from
*
* Local wrapper for FIELD_GET() to force u32 and for consistency with
* REG_FIELD_PREP(), REG_BIT() and REG_GENMASK().
*
* @return: Masked and shifted value of the field defined by @__mask in @__val.
*/
#define REG_FIELD_GET(__mask, __val) ((u32)FIELD_GET(__mask, __val))
/**
* REG_FIELD_GET64() - Extract a u64 bitfield value
* @__mask: shifted mask defining the field's length and position
* @__val: value to extract the bitfield value from
*
* Local wrapper for FIELD_GET() to force u64 and for consistency with
* REG_GENMASK64().
*
* @return: Masked and shifted value of the field defined by @__mask in @__val.
*/
#define REG_FIELD_GET64(__mask, __val) ((u64)FIELD_GET(__mask, __val))
/**
* REG_FIELD_MAX() - produce the maximum value representable by a field
* @__mask: shifted mask defining the field's length and position
*
* Local wrapper for FIELD_MAX() to return the maximum bit value that can
* be held in the field specified by @_mask, cast to u32 for consistency
* with other macros.
*/
#define REG_FIELD_MAX(__mask) ((u32)FIELD_MAX(__mask))
#define REG_MASKED_FIELD(mask, value) \
(BUILD_BUG_ON_ZERO(__builtin_choose_expr(__builtin_constant_p(mask), (mask) & 0xffff0000, 0)) + \
BUILD_BUG_ON_ZERO(__builtin_choose_expr(__builtin_constant_p(value), (value) & 0xffff0000, 0)) + \
BUILD_BUG_ON_ZERO(__builtin_choose_expr(__builtin_constant_p(mask) && __builtin_constant_p(value), (value) & ~(mask), 0)) + \
((mask) << 16 | (value)))
#define REG_MASKED_FIELD_ENABLE(a) \
(__builtin_choose_expr(__builtin_constant_p(a), REG_MASKED_FIELD((a), (a)), ({ typeof(a) _a = (a); REG_MASKED_FIELD(_a, _a); })))
#define REG_MASKED_FIELD_DISABLE(a) \
(REG_MASKED_FIELD((a), 0))
#endif