From: Jani Nikula Date: Wed, 25 Feb 2026 17:57:03 +0000 (+0200) Subject: drm/i915/reg: make masked field helpers constexpr X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=b6d558af2d6362f9fed704302071bc765f395e0d;p=thirdparty%2Flinux.git drm/i915/reg: make masked field helpers constexpr 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 Acked-by: Rodrigo Vivi Link: https://patch.msgid.link/788f538cc71dec0db25e0c768e8945bef6f9701c.1772042022.git.jani.nikula@intel.com Signed-off-by: Jani Nikula --- diff --git a/drivers/gpu/drm/i915/i915_reg_defs.h b/drivers/gpu/drm/i915/i915_reg_defs.h index e81fac8ab51b5..c39b3a5dafe69 100644 --- a/drivers/gpu/drm/i915/i915_reg_defs.h +++ b/drivers/gpu/drm/i915/i915_reg_defs.h @@ -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