Re: [PATCH 3/3] net/eth: fix link handling

[Sascha Hauer <s.hauer@pengutronix.de>]

On Wed, Sep 26, 2012 at 03:03:53PM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 14:50 Wed 26 Sep     , Jan Lübbe wrote:
> > On Wed, 2012-09-26 at 14:43 +0200, Sascha Hauer wrote:
> > > The eth->active is for tracking whether a device is opened (thus we have
> > > to call eth->halt). With this patch eth->active == 0 could mean:
> > > 
> > > a) device not opened
> > > b) opened, but no link
> > > 
> > > This is asking for trouble. A bit only has two states, you should not
> > > encode three states in it.
> > 
> > Yes. We should not repeatedly open the device to check link status
> > again. A open (active==1) device with no link is perfectly valid, it
> > just can't be used for TX/RX.
> > 
> > So if we have an open device in TX/RX and
> >   link down: recheck link
> >   link up: recheck link if the last check is "too old"
> > 
> > This way we notice both link going down and up, while not wasting time
> > when we are waiting for link up.
> except this can not work in barebox. In linux you can as you have a schedule
> work that check the phy status. In barebox we do not do so and I do not want
> it (slow down the boot). So we check it at the open only and only once. When
> the phy is up we do not check it again.
> 
> Remember we are in a bootloader not in an os we need to do some concession.

int check_link_status(void)
{
	if (is_timeout(last_link_check, SECOND)) {
		do_link_check();
		last_link_check = get_time_ns();
	}
}

eth_rx(void)
{
	check_link_status();
}

Sascha

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