From: Fabio Estevam fabio.estevam@freescale.com
Add support for the order_base_2() macro (and its dependencies) from the Linux kernel.
This is useful for the SPI NOR unlock function.
Signed-off-by: Fabio Estevam fabio.estevam@freescale.com --- Changes since v2: - None. Changes since v1: - None.
arch/arm/include/asm/bitops.h | 56 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+)
diff --git a/arch/arm/include/asm/bitops.h b/arch/arm/include/asm/bitops.h index 9b78043..b9b6d21 100644 --- a/arch/arm/include/asm/bitops.h +++ b/arch/arm/include/asm/bitops.h @@ -108,6 +108,62 @@ static inline int __ilog2(unsigned int x) return generic_fls(x) - 1; }
+static inline int fls64(__u64 x) +{ + if (x == 0) + return 0; + return generic_fls(x) + 1; +} + +static inline unsigned fls_long(unsigned long l) +{ + if (sizeof(l) == 4) + return generic_fls(l); + return fls64(l); +} + +/* + * round up to nearest power of two + */ +static inline __attribute__((const)) +unsigned long __roundup_pow_of_two(unsigned long n) +{ + return 1UL << fls_long(n - 1); +} + +/** + * roundup_pow_of_two - round the given value up to nearest power of two + * @n - parameter + * + * round the given value up to the nearest power of two + * - the result is undefined when n == 0 + * - this can be used to initialise global variables from constant data + */ +#define roundup_pow_of_two(n) \ +( \ + __builtin_constant_p(n) ? ( \ + (n == 1) ? 1 : \ + (1UL << (__ilog2((n) - 1) + 1)) \ + ) : \ + __roundup_pow_of_two(n) \ +) + +/** + * order_base_2 - calculate the (rounded up) base 2 order of the argument + * @n: parameter + * + * The first few values calculated by this routine: + * ob2(0) = 0 + * ob2(1) = 0 + * ob2(2) = 1 + * ob2(3) = 2 + * ob2(4) = 2 + * ob2(5) = 3 + * ... and so on. + */ + +#define order_base_2(n) __ilog2(roundup_pow_of_two(n)) + /* * ffz = Find First Zero in word. Undefined if no zero exists, * so code should check against ~0UL first..