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| author | Simon Horman <horms+renesas@verge.net.au> | 2019-03-25 19:35:53 +0300 |
|---|---|---|
| committer | Geert Uytterhoeven <geert+renesas@glider.be> | 2019-04-02 10:50:48 +0300 |
| commit | cb8be119d21d8a0affc3598a928dd0baf5da238f (patch) | |
| tree | a9cad79fb039220cd64061c02f34afc3eecb5a84 /include/linux/math64.h | |
| parent | e0836e36384321ab1b4af05ab441c0c59a972596 (diff) | |
| download | linux-cb8be119d21d8a0affc3598a928dd0baf5da238f.tar.xz | |
math64: New DIV64_U64_ROUND_CLOSEST helper
Provide DIV64_U64_ROUND_CLOSEST helper which performs division rounded to
the closest integer using an unsigned 64bit dividend and divisor.
This will be used in a follow-up patch to allow calculation of clock
divisors with high frequency parents in the R-Car Gen3 CPG MSSR driver
where overflow occurs if either the dividend or divisor is 32bit.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Diffstat (limited to 'include/linux/math64.h')
| -rw-r--r-- | include/linux/math64.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/math64.h b/include/linux/math64.h index bb2c84afb80c..65bef21cdddb 100644 --- a/include/linux/math64.h +++ b/include/linux/math64.h @@ -284,4 +284,17 @@ static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor) #define DIV64_U64_ROUND_UP(ll, d) \ ({ u64 _tmp = (d); div64_u64((ll) + _tmp - 1, _tmp); }) +/** + * DIV64_U64_ROUND_CLOSEST - unsigned 64bit divide with 64bit divisor rounded to nearest integer + * @dividend: unsigned 64bit dividend + * @divisor: unsigned 64bit divisor + * + * Divide unsigned 64bit dividend by unsigned 64bit divisor + * and round to closest integer. + * + * Return: dividend / divisor rounded to nearest integer + */ +#define DIV64_U64_ROUND_CLOSEST(dividend, divisor) \ + ({ u64 _tmp = (divisor); div64_u64((dividend) + _tmp / 2, _tmp); }) + #endif /* _LINUX_MATH64_H */ |