[WATCHDOG] bfin: fix max timeout calculation

Relying on overflow/wrap around isn't exact because if you wrap far
enough, you get back to "valid" values.

Reported-by: Thorsten Pohlmann <pohlmann@tetronik.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: stable <stable@kernel.org>
This commit is contained in:
Mike Frysinger 2010-02-15 19:32:25 -05:00 committed by Wim Van Sebroeck
parent aea187c46f
commit 3dae93ec3e

View file

@ -1,9 +1,8 @@
/*
* Blackfin On-Chip Watchdog Driver
* Supports BF53[123]/BF53[467]/BF54[2489]/BF561
*
* Originally based on softdog.c
* Copyright 2006-2007 Analog Devices Inc.
* Copyright 2006-2010 Analog Devices Inc.
* Copyright 2006-2007 Michele d'Amico
* Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>
*
@ -137,13 +136,15 @@ static int bfin_wdt_running(void)
*/
static int bfin_wdt_set_timeout(unsigned long t)
{
u32 cnt;
u32 cnt, max_t, sclk;
unsigned long flags;
stampit();
sclk = get_sclk();
max_t = -1 / sclk;
cnt = t * sclk;
stamp("maxtimeout=%us newtimeout=%lus (cnt=%#x)", max_t, t, cnt);
cnt = t * get_sclk();
if (cnt < get_sclk()) {
if (t > max_t) {
printk(KERN_WARNING PFX "timeout value is too large\n");
return -EINVAL;
}