Commit b6d558af authored by Jani Nikula's avatar Jani Nikula
Browse files

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: default avatarMichał Grzelak <michal.grzelak@intel.com>
Acked-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patch.msgid.link/788f538cc71dec0db25e0c768e8945bef6f9701c.1772042022.git.jani.nikula@intel.com


Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
parent f5c8f824

drivers/gpu/drm/i915/i915_reg_defs.h

+11 −11
Original line number Diff line number Diff line
@@ -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