Commit 5b572e8a authored by Lucas De Marchi's avatar Lucas De Marchi Committed by Yury Norov
Browse files

bits: introduce fixed-type BIT_U*() 



Implement fixed-type BIT_U*() to help drivers add stricter checks,
like it was done for GENMASK_U*().

Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
Acked-by: default avatarJani Nikula <jani.nikula@intel.com>
Co-developed-by: default avatarVincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: default avatarVincent Mailhol <mailhol.vincent@wanadoo.fr>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarYury Norov <yury.norov@gmail.com>
parent 19408200

include/linux/bits.h

+19 −1
Original line number Diff line number Diff line
@@ -24,7 +24,7 @@ 
/*

 * Missing asm support

 *

 * GENMASK_U*() depend on BITS_PER_TYPE() which relies on sizeof(),

 * GENMASK_U*() and BIT_U*() depend on BITS_PER_TYPE() which relies on sizeof(),

 * something not available in asm. Nevertheless, fixed width integers is a C

 * concept. Assembly code can rely on the long and long long versions instead.

 */
@@ -55,6 +55,24 @@ 
#define GENMASK_U32(h, l)	GENMASK_TYPE(u32, h, l)

#define GENMASK_U64(h, l)	GENMASK_TYPE(u64, h, l)



/*

 * Fixed-type variants of BIT(), with additional checks like GENMASK_TYPE(). The

 * following examples generate compiler warnings due to -Wshift-count-overflow:

 *

 * - BIT_U8(8)

 * - BIT_U32(-1)

 * - BIT_U32(40)

 */

#define BIT_INPUT_CHECK(type, nr) \

	BUILD_BUG_ON_ZERO(const_true((nr) >= BITS_PER_TYPE(type)))



#define BIT_TYPE(type, nr) ((type)(BIT_INPUT_CHECK(type, nr) + BIT_ULL(nr)))



#define BIT_U8(nr)	BIT_TYPE(u8, nr)

#define BIT_U16(nr)	BIT_TYPE(u16, nr)

#define BIT_U32(nr)	BIT_TYPE(u32, nr)

#define BIT_U64(nr)	BIT_TYPE(u64, nr)



#else /* defined(__ASSEMBLY__) */



/*