Date: Wed, 23 Nov 2005 09:50:44 -0700 (MST) From: "M. Warner Losh" <imp@bsdimp.com> To: mayong@mail.com Cc: freebsd-drivers@freebsd.org Subject: Re: timer_list for FreeBSD? Message-ID: <20051123.095044.88000142.imp@bsdimp.com> In-Reply-To: <20051123092444.D826E164293@ws1-4.us4.outblaze.com> References: <20051123092444.D826E164293@ws1-4.us4.outblaze.com>
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In message: <20051123092444.D826E164293@ws1-4.us4.outblaze.com>
"Yong Ma" <mayong@mail.com> writes:
: In my work I send some data to the card and wait for a result in a
: loop.but sometimes it can't get it ,so the driver run and run and
: can't get out of the loop.I need something like timer_list in Linux
: with which I can decide the max time the loop will run.I searched it
: in the source code but found little about that.Anyone can help?
Typically this sort of thing is done in FreeBSD in a more ad-hoc way:
/*
* Wait at most 1ms for the busy bit to flip. Datasheet
* says it will take up to 250us, so add a sane margin of
* error in case they are wrong. Note: GetStatus takes 1us
* to perform the i/o.
*/
limit = 1000;
while ((GetStatus() & BusyBit) && limit-- > 0)
continue;
There's no easy API that will let you limit it to a fixed time. The
above typically is sufficient for 'don't loop forever' so nothing
fancier has been created.
Warner
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