[PATCH][NET] several cleanups and bugfixes for fec.c: preserve MII/RMII setting in fec_stop()

Lothar Waßmann
2011-12-07T10:42:28Z

Hi,

Shawn Guo writes:
> On Tue, Dec 06, 2011 at 11:27:14AM +0100, Lothar Wa?mann wrote:
> > Additionally to setting the ETHER_EN bit in FEC_ECNTRL the MII/RMII
> > setting in FEC_R_CNTRL needs to be preserved to keep the MII interface
>
> s/MII/RMII? From what I see from imx28 and imx6q RM, the reset state
> for this setting is MII mode.
>
> > functional.
> >
> > Signed-off-by: Lothar Wa?mann <LW@KARO-electronics.de>
> > ---
> > drivers/net/ethernet/freescale/fec.c | 5 ++++-
> > 1 files changed, 4 insertions(+), 1 deletions(-)
>
> I assume this is fixing a problem you are seeing on imx28 only.
> Do you see the problem on imx53/51?
>
No. i.MX53 uses the RMII gasket which is not affected by resetting the
controller. And imMX51 does not support RMII at all.

> >
> > diff --git a/drivers/net/ethernet/freescale/fec.c b/drivers/net/ethernet/freescale/fec.c
> > index 11534b9..ab0afb5 100644
> > --- a/drivers/net/ethernet/freescale/fec.c
> > +++ b/drivers/net/ethernet/freescale/fec.c
> > @@ -515,6 +515,7 @@ fec_stop(struct net_device *ndev)
> > struct fec_enet_private *fep = netdev_priv(ndev);
> > const struct platform_device_id *id_entry =
> > platform_get_device_id(fep->pdev);
> > + u32 rmii_mode = readl(fep->hwp + FEC_R_CNTRL) & (1 << 8);
>
> This bit is only available on ENET (imx28 and imx6q). Do we want to
> do the same thing for FEC (imx25/27/35/51/53)?
>
No. AFAICT that's not necessary there.

> > /* We cannot expect a graceful transmit stop without link !!! */
> > if (fep->link) {
> > @@ -531,8 +532,10 @@ fec_stop(struct net_device *ndev)
> > writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
> >
> > /* We have to keep ENET enabled to have MII interrupt stay working */
> > - if (id_entry->driver_data & FEC_QUIRK_ENET_MAC)
> > + if (id_entry->driver_data & FEC_QUIRK_ENET_MAC) {
> > writel(2, fep->hwp + FEC_ECNTRL);
> > + writel(rmii_mode, fep->hwp + FEC_R_CNTRL);
> > + }
> > }
>
> On imx6q, we have two bits, bit 6 and 8 of FEC_R_CNTRL, to select MII
> interface among MII, RMII and RGMII modes. I'm not sure if we will
> run into the same problem for RGMII mode. What's your test setup?
> I would try to reproduce it here.
>
I'm using a TX28 which has the Ethernet PHY connected in RMII
mode. You should see the problem, if you unplug the ethernet cable on
a configured link. Without this patch the kernel will not detect when
the cable is plugged back in.

Lothar Wa?mann
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