Re: [PATCH 2/3] [POWERPC] fsl_soc: add support for gianfar forfixed-link property

[Joakim Tjernlund]

On Tue, 2007-11-27 at 14:39 +0300, Anton Vorontsov wrote:
> On Mon, Nov 26, 2007 at 04:04:08PM +0100, Joakim Tjernlund wrote:
> > On Mon, 2007-11-26 at 17:29 +0300, Vitaly Bordug wrote:
> > > fixed-link says: register new "Fixed/emulated PHY", i.e. PHY that
> > > not connected to the real MDIO bus.
> > > 
> > > Signed-off-by: Vitaly Bordug <vitb@xxxxxxxxxxxxxxxxxxx>
> > > Signed-off-by: Anton Vorontsov <avorontsov@xxxxxxxxxxxxx>
> > > 
> > > ---
> > > 
> > >  Documentation/powerpc/booting-without-of.txt |    3 +
> > >  arch/powerpc/sysdev/fsl_soc.c                |   56 ++++++++++++++++++--------
> > >  2 files changed, 42 insertions(+), 17 deletions(-)
> > > 
> > > 
> > > diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt
> > > index e9a3cb1..cf25070 100644
> > > --- a/Documentation/powerpc/booting-without-of.txt
> > > +++ b/Documentation/powerpc/booting-without-of.txt
> > > @@ -1254,6 +1254,9 @@ platforms are moved over to use the flattened-device-tree model.
> > >        services interrupts for this device.
> > >      - phy-handle : The phandle for the PHY connected to this ethernet
> > >        controller.
> > > +    - fixed-link : <a b c> where a is emulated phy id - choose any,
> > > +      but unique to the all specified fixed-links, b is duplex - 0 half,
> > > +      1 full, c is link speed - d#10/d#100/d#1000.
> > 
> > Good work!
> > May I suggest adding a "d" to <a b c> where d is flow control - 0 no, 1 yes
> 
> Well, I see no reference of the "flow" neither in the include/linux/mii.h
> nor in the drivers/net/phy/*. :-/ Thus today there is no such register
> bit we can emulate?..

Well, as good as I can recall, flow control(pause) is something that the
PHY negotiates, just like FDX/HDX and should be dealt with in the
adjust_link callback but not many do currently.

If you seach for pause in phy_device.c you will find it.

> 
> > flow control or not just popped up here today so I got a use for it.
> 
> ..and I looked into few drivers (gianfar, ucc), and they seem to use
> hard-coded flow control values, thus they don't speak to the PHYs
> about that.

Yes, but they should.

> 
> Can you give any reference to the driver that needs that parameter?
> Does it use PHY subsystem to obtain flow-control on/off information?
> 
> Thanks,
> 
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