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

Lothar Waßmann
2011-12-07T10:49:09Z

Hi,

Shawn Guo writes:
> On Wed, Dec 07, 2011 at 11:42:28AM +0100, Lothar Wa?mann wrote:
> > 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.
> >
> So you need to check it's actually running on ENET before accessing
> the bit.
>
That's done in the place where the register is being written:
| if (id_entry->driver_data & FEC_QUIRK_ENET_MAC) {
| writel(2, fep->hwp + FEC_ECNTRL);
| writel(rmii_mode, fep->hwp + FEC_R_CNTRL);
| }

We could save one register read by doing the check also for the read,
but that would further complicate the code.

Lothar Wa?mann
--
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