[U-Boot-Users] [PATCH 3/7 v6] ARM: Add arm1176 core with S3C6400 SoC

Jens Gehrlein sew_s at tqs.de
Thu Aug 7 12:00:59 CEST 2008


Hi Guennadi,

Guennadi Liakhovetski schrieb:

> diff --git a/cpu/arm1176/s3c64xx/interrupts.c b/cpu/arm1176/s3c64xx/interrupts.c
[snip]
> +void udelay(unsigned long usec)
> +{
> +	unsigned long long tmp;
> +	ulong tmo;
> +
> +	tmo = (usec + 9) / 10;
> +	tmp = get_ticks() + tmo;	/* get current timestamp */
> +
> +	while (get_ticks() < tmp)/* loop till event */
> +		 /*NOP*/;
> +}

I tried to follow the interrupt init function, but it's difficult.
What is the least possible delay with the udelay function?
I remember that i.mx31 udelay cannot currently be below 30 microsseconds 
due to the low input clock. If someone uses udelay(1) in polling loops 
with timeout, the actual duration is much more longer than assumed.

Kind regards,
Jens




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