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drm/i915/reg: make masked field helpers constexpr

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Make it possible to use _MASKED_FIELD(), _MASKED_BIT_ENABLE() and
_MASKED_BIT_DISABLE() in contexts that require integer constant
expressions. This increases their usefulness at the small cost of making
the warnings from build time checks less helpful.

Reviewed-by: Michał Grzelak <michal.grzelak@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patch.msgid.link/788f538cc71dec0db25e0c768e8945bef6f9701c.1772042022.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
This commit is contained in:
Jani Nikula 2026-02-25 19:57:03 +02:00
parent f5c8f824a4
commit b6d558af2d
1 changed files with 11 additions and 11 deletions
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22
drivers/gpu/drm/i915/i915_reg_defs.h
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@ -106,17 +106,17 @@
BUILD_BUG_ON_ZERO(__builtin_choose_expr(__is_constexpr(__val), (~((__mask) >> __bf_shf(__mask)) & (__val)), 0))))
#define __MASKED_FIELD(mask, value) ((mask) << 16 | (value))
#define _MASKED_FIELD(mask, value) ({ \
if (__builtin_constant_p(mask)) \
BUILD_BUG_ON_MSG(((mask) & 0xffff0000), "Incorrect mask"); \
if (__builtin_constant_p(value)) \
BUILD_BUG_ON_MSG((value) & 0xffff0000, "Incorrect value"); \
if (__builtin_constant_p(mask) && __builtin_constant_p(value)) \
BUILD_BUG_ON_MSG((value) & ~(mask), \
"Incorrect value for mask"); \
__MASKED_FIELD(mask, value); })
#define _MASKED_BIT_ENABLE(a) ({ typeof(a) _a = (a); _MASKED_FIELD(_a, _a); })
#define _MASKED_BIT_DISABLE(a) (_MASKED_FIELD((a), 0))
#define _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)) + \
__MASKED_FIELD(mask, value))
#define _MASKED_BIT_ENABLE(a) \
(__builtin_choose_expr(__builtin_constant_p(a), _MASKED_FIELD((a), (a)), ({ typeof(a) _a = (a); _MASKED_FIELD(_a, _a); })))
#define _MASKED_BIT_DISABLE(a) \
(_MASKED_FIELD((a), 0))
/*
* Given the first two numbers __a and __b of arbitrarily many evenly spaced