UDELAY_MULT        41 arch/arm/include/asm/delay.h #define UDELAY_MULT	UL(2147 * HZ + 483648 * HZ / 1000000)
UDELAY_MULT        42 arch/riscv/lib/delay.c #define UDELAY_MULT	(2147UL * HZ + 483648UL * HZ / 1000000UL)