Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 <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>
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drivers/gpu/drm/i915/i915_reg_defs.h
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drivers/gpu/drm/i915/i915_reg_defs.h
···
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BUILD_BUG_ON_ZERO(__builtin_choose_expr(__is_constexpr(__val), (~((__mask) >> __bf_shf(__mask)) & (__val)), 0))))
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#define __MASKED_FIELD(mask, value) ((mask) << 16 | (value))
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-
#define _MASKED_FIELD(mask, value) ({ \
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if (__builtin_constant_p(mask)) \
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BUILD_BUG_ON_MSG(((mask) & 0xffff0000), "Incorrect mask"); \
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if (__builtin_constant_p(value)) \
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BUILD_BUG_ON_MSG((value) & 0xffff0000, "Incorrect value"); \
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if (__builtin_constant_p(mask) && __builtin_constant_p(value)) \
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BUILD_BUG_ON_MSG((value) & ~(mask), \
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"Incorrect value for mask"); \
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__MASKED_FIELD(mask, value); })
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#define _MASKED_BIT_ENABLE(a) ({ typeof(a) _a = (a); _MASKED_FIELD(_a, _a); })
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#define _MASKED_BIT_DISABLE(a) (_MASKED_FIELD((a), 0))
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+
#define _MASKED_FIELD(mask, value) \
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(BUILD_BUG_ON_ZERO(__builtin_choose_expr(__builtin_constant_p(mask), (mask) & 0xffff0000, 0)) + \
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BUILD_BUG_ON_ZERO(__builtin_choose_expr(__builtin_constant_p(value), (value) & 0xffff0000, 0)) + \
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BUILD_BUG_ON_ZERO(__builtin_choose_expr(__builtin_constant_p(mask) && __builtin_constant_p(value), (value) & ~(mask), 0)) + \
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__MASKED_FIELD(mask, value))
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+
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+
#define _MASKED_BIT_ENABLE(a) \
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(__builtin_choose_expr(__builtin_constant_p(a), _MASKED_FIELD((a), (a)), ({ typeof(a) _a = (a); _MASKED_FIELD(_a, _a); })))
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+
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#define _MASKED_BIT_DISABLE(a) \
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(_MASKED_FIELD((a), 0))
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/*
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* Given the first two numbers __a and __b of arbitrarily many evenly spaced