From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alessandro Rubini <rubini-list@gnudd.com>
Date: Thu, 6 Aug 2009 12:12:41 +0200
Subject: [U-Boot] PATCH mtd CFI flash: timeout calculation underflow
	if	imprecise 1kHz timer: fix
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References: <4A7AA72C.8010704@imagos.it> 
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> With old configuration it could happen tout=0 if CONFIG_SYS_HZ<1000
> solved using an unsigned long long

I had the same problem with an ancient version of a vendor-ported u-boot. There
my CFG_HZ was 100, so the timeout was 0.

I used this, which avoids the preprocessor conditional. Since the HZ value
is a compile-time constant, the compiler chooses the if or else branch and doesn't
spit a run-time conditional.2

        if (CFG_HZ > 100000)
                tout *= CFG_HZ/1000;  /* for a big HZ, avoid overflow */
        else
                tout = tout * CFG_HZ / 1000 + 1;


/alessandro