From: Russell King Date: Mon, 10 Jan 2011 23:55:59 +0000 (+0000) Subject: ARM: udelay: prevent math rounding resulting in short udelays X-Git-Tag: MMI-PSA29.97-13-9~21009^2~16 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=56949d414acd30353fdba4b64876a0a7953a7b77;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git ARM: udelay: prevent math rounding resulting in short udelays We perform the microseconds to loops calculation using a number of multiplies and shift rights. Each shift right rounds down the resulting value, which can result in delays shorter than requested. Ensure that we always round up. Signed-off-by: Russell King --- diff --git a/arch/arm/lib/delay.S b/arch/arm/lib/delay.S index 8d6a8762ab88..3c9a05c8d20b 100644 --- a/arch/arm/lib/delay.S +++ b/arch/arm/lib/delay.S @@ -25,11 +25,15 @@ ENTRY(__udelay) ldr r2, .LC1 mul r0, r2, r0 ENTRY(__const_udelay) @ 0 <= r0 <= 0x7fffff06 + mov r1, #-1 ldr r2, .LC0 ldr r2, [r2] @ max = 0x01ffffff + add r0, r0, r1, lsr #32-14 mov r0, r0, lsr #14 @ max = 0x0001ffff + add r2, r2, r1, lsr #32-10 mov r2, r2, lsr #10 @ max = 0x00007fff mul r0, r2, r0 @ max = 2^32-1 + add r0, r0, r1, lsr #32-6 movs r0, r0, lsr #6 moveq pc, lr