Re: [PATCH net-next] net: systemport: update UMAC_CMD only when link is detected

[David Miller <davem@davemloft.net>]

From: Florian Fainelli <f.fainelli@gmail.com>
Date: Tue,  2 Sep 2014 11:17:07 -0700

> When we bring the interface down, phy_stop() will schedule the PHY
> state machine to call our link adjustment callback. By the time we do so,
> we may have clock gated off the SYSTEMPORT hardware block, and this will
> cause bus errors to happen in bcm_sysport_adj_link():
> 
> Make sure that we only touch the UMAC_CMD register when there is an
> actual link. This is safe to do for two reasons:
> 
> - updating the Ethernet MAC registers only make sense when a physical
>   link is present
> - the PHY library state machine first set phydev->link = 0 before
>   invoking phydev->adjust_link in the PHY_HALTED case
> 
> This is a similar fix to the GENET one:
> c677ba8b3c47650358572091ed8a6af50bfca877 ("net: bcmgenet: update
> UMAC_CMD only when link is detected").
> 
> Fixes: 80105befdb4b ("net: systemport: add Broadcom SYSTEMPORT Ethernet MAC driver")
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

Applied, thanks Florian.