lib: div64: Add support for round up of div64_u64

Most of the frequencies are not rounded up to a proper number.
When we need to devide these frequencies to get a number for example
frequency in Mhz, we see it as one less than the actual intended value.
Ex: If we want to get Mhz from frequency 199999994hz, we will calculate
it using div64_u64(199999994, 1000000) and we will get 199Mhz in place
of 200Mhz.

Add a macro DIV64_U64_ROUND_UP for rounding up div64_u64. This is taken
from linux 'commit 68600f623d69("mm: don't miss the last page because of
round-off error")'.

Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/f9fdcba76cd692ae436b1d7883b490e3dc207231.1645626962.git.michal.simek@xilinx.com

diff --git a/include/linux/math64.h b/include/linux/math64.h
index 08584c8f237f39640650c9b93ee794f6ba8f5b2d..eaa9fd5b9685faee28a240c032ead689f8e4e1cc 100644 (file)
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -48,6 +48,9 @@ static inline u64 div64_u64(u64 dividend, u64 divisor)
        return dividend / divisor;
 }
 
+#define DIV64_U64_ROUND_UP(ll, d)      \
+       ({ u64 _tmp = (d); div64_u64((ll) + _tmp - 1, _tmp); })
+
 /**
  * div64_s64 - signed 64bit divide with 64bit divisor
  */