netdev/fec: fix ifconfig eth0 down hang issue (v4)

BugLink: http://bugs.launchpad.net/bugs/559065

v4:
 - don't touch suspend/resume functions in this patch
 - set fep->phy_dev = NULL in the fec_enet_mii_probe() entry

v3:
if fec_enet_mii_probe() fails, we should exit the open and resume functions
properly and give up further operations without a proper PHY connected.

v2:
Check fec_enet_mii_probe() return value directly, instead of fep->phy_dev

v1:
In ethernet connection open/close function, we need to use phy_connect
and phy_disconnect operation before we start/stop phy. Otherwise it will
cause system hang. Also suspend/resume needs the same fix.

Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
---
 drivers/net/fec.c |   14 +++++++++++++-
 1 files changed, 13 insertions(+), 1 deletions(-)

Bryan Wu wrote:
> BugLink: http://bugs.launchpad.net/bugs/559065
>
> v4:
>  - don't touch suspend/resume functions in this patch
>  - set fep->phy_dev = NULL in the fec_enet_mii_probe() entry
>
> v3:
> if fec_enet_mii_probe() fails, we should exit the open and resume functions
> properly and give up further operations without a proper PHY connected.
>
> v2:
> Check fec_enet_mii_probe() return value directly, instead of fep->phy_dev
>
> v1:
> In ethernet connection open/close function, we need to use phy_connect
> and phy_disconnect operation before we start/stop phy. Otherwise it will
> cause system hang. Also suspend/resume needs the same fix.
>
> Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
> ---
>  drivers/net/fec.c |   14 +++++++++++++-
>  1 files changed, 13 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/net/fec.c b/drivers/net/fec.c
> index 2280373..8f0237b 100644
> --- a/drivers/net/fec.c
> +++ b/drivers/net/fec.c
> @@ -691,6 +691,8 @@ static int fec_enet_mii_probe(struct net_device *dev)
>  	struct phy_device *phy_dev = NULL;
>  	int phy_addr;
>  
> +	fep->phy_dev = NULL;
> +
>  	/* find the first phy */
>  	for (phy_addr = 0; phy_addr < PHY_MAX_ADDR; phy_addr++) {
>  		if (fep->mii_bus->phy_map[phy_addr]) {
> @@ -929,7 +931,13 @@ fec_enet_open(struct net_device *dev)
>  		return ret;
>  
>  	/* schedule a link state check */
> +	ret = fec_enet_mii_probe(dev);
> +	if (!ret) {
> +		fec_enet_free_buffers(dev);
> +		return ret;
> +	}
>  	phy_start(fep->phy_dev);
> +
>  	netif_start_queue(dev);
>  	fep->opened = 1;
>  	return 0;
> @@ -942,10 +950,13 @@ fec_enet_close(struct net_device *dev)
>  
>  	/* Don't know what to do yet. */
>  	fep->opened = 0;
> -	phy_stop(fep->phy_dev);
>  	netif_stop_queue(dev);
> +
>  	fec_stop(dev);
>  
> +	if (fep->phy_dev)
> +		phy_disconnect(fep->phy_dev);
> +
>          fec_enet_free_buffers(dev);
>  	clk_disable(fep->clk);
>  
> @@ -1409,6 +1420,7 @@ fec_resume(struct platform_device *dev)
>  {
>  	struct net_device *ndev = platform_get_drvdata(dev);
>  	struct fec_enet_private *fep;
> +	int ret;
>  
>   

What'a a mess. Sorry, please ignore this one. I will send out a new one 
soon.

-Bryan

>  	if (ndev) {
>  		fep = netdev_priv(ndev);
>