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Re: RFC: PHY Abstraction Layer II

To: Jeff Garzik <jgarzik@xxxxxxxxx>
Subject: Re: RFC: PHY Abstraction Layer II
From: Kumar Gala <kumar.gala@xxxxxxxxxxxxx>
Date: Wed, 25 May 2005 18:00:33 -0500
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>, ML linuxppc-embedded <linuxppc-embedded@xxxxxxxxxx>, Fleming Andy-afleming <afleming@xxxxxxxxxxxxx>, Netdev <netdev@xxxxxxxxxxx>, James Chapman <jchapman@xxxxxxxxxxx>
In-reply-to: <30d87aabd768216ef8bee800f3e09b9e@freescale.com>
References: <1107b64b01fb8e9a6c84359bb56881a6@freescale.com> <1110334456.32556.21.camel@gaston> <20050308194229.41c23707.davem@davemloft.net> <1110340214.32524.32.camel@gaston> <57a429f8eb807987d88b06129861d507@freescale.com> <4230D1AC.5070506@katalix.com> <ba5d844255b5ba76b2685f9397faf689@freescale.com> <423734FB.40101@katalix.com> <96c50184a02557c88dee0e6d17f3a539@freescale.com> <42625DDB.4090600@katalix.com> <30d87aabd768216ef8bee800f3e09b9e@freescale.com>
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Jeff,

Where do we stand on this. Are there changes you feel need to be made? Some other issue? It would like to know what we need to do to get this in post 2.6.12.

thanks

- kumar

On May 10, 2005, at 12:04 PM, Fleming Andy-afleming wrote:



On Apr 17, 2005, at 08:00, James Chapman wrote:

> Andy Fleming wrote:
>> Ok, here's the new patch with changes suggested by James Chapman:
>
> I guess I still have questions about the way interrupts are used.
>
> Using an interrupt to schedule a work queue which then sets a variable
> that is used by a timer seems odd. Why not do all the work in the work
> queue and schedule it from the interrupt handler or timer?


Ok, I've set up a new system for handling interrupts.  There are now
 two "special" interrupt values, PHY_POLL, and PHY_IGNORE_INTERRUPT. 
 The first one is used to indicate that the PHY layer will poll the PHY
for state changes, and won't enable interrupts.  The second indicates
that the PHY layer will neither poll, nor enable interrupts, and thus
will allow the driver to handle interrupts.  The PHY layer will still
operate its state machine, though.

The driver must insure a couple things:

1) It must set phydev->state to PHY_CHANGELINK
2) It must do that in a work queue (or other non-interrupt time)

The first one tells the PHY layer that the link state changed (it has
to grab a lock to do this).  The second one is required in order to
properly take the lock.

>
 > Also, did you mean to leave the #if 0 code in davicom.c?

For now.  It worked around a problem some people were reporting, so I'd
like to see if they report it again now that the code's out.  If so,
they have a fairly easy fix, and I can reinsert it (or at least
reevaluate it) in the future.

>
 > /james

Andy
<phy_05_09_2005.patch><ATT191442.txt>


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