netdev - Re: [PATCH 1/2] [v4] net: emac: emac gigabit ethernet controller driver

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Date:	Tue, 10 May 2016 18:18:28 -0500
From:	Timur Tabi <timur@...eaurora.org>
To:	Florian Fainelli <f.fainelli@...il.com>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	linux-arm-msm@...r.kernel.org, sdharia@...eaurora.org,
	Shanker Donthineni <shankerd@...eaurora.org>,
	Greg Kroah-Hartman <greg@...ah.com>, vikrams@...eaurora.org,
	cov@...eaurora.org, gavidov@...eaurora.org,
	Rob Herring <robh+dt@...nel.org>, andrew@...n.ch,
	bjorn.andersson@...aro.org, Mark Langsdorf <mlangsdo@...hat.com>,
	Jon Masters <jcm@...hat.com>,
	Andy Gross <agross@...eaurora.org>,
	"David S. Miller" <davem@...emloft.net>
Subject: Re: [PATCH 1/2] [v4] net: emac: emac gigabit ethernet controller
 driver

Florian Fainelli wrote:
> Are you utilizing the PHYLIB APIs properly? You need at least a
> phy_start() to start the PHY state machine, and an adjust_link callback
> to be provided to phy_connect() (or of_phy_connect()) to manage link
> state changes. And that's the very basic minimum here, there could be
> additional APIs that you may end up using.
>
> There are tons of example in tree of drivers doing this, bcmgenet,
> bcmsysport, tg3 etc.

Thank you.  I think I finally got phylib working, more or less.

Unfortunately, it seems I have some kind of race condition.  The driver 
has a lot that's wrong with it, and I'm trying to fix it all.  One crazy 
the driver does is it create a workqueue to handle a lot of the tasks 
that would normally be handled in the interrupt handler itself.

With phylib support, I know my driver can call phy_mac_interrupt() when 
it gets a link status change interrupt.  I then have an .adjust_link 
callback which starts or stops the mac accordingly.

My problem is that I'm not really sure what adjust_link is supposed to 
be doing.  In addition, it seems that I need to keep the workqueue 
running, otherwise the interface will not function.  I bring the 
interface up, and the driver reports success, but pings do not work.

I'm getting really frustrated.  The sample code isn't really helping a 
whole lot, because I lack a fundamental understanding of what needs to 
be done.  None of the documentation I've read is helpful, and I don't 
know how to debug it.

Can you give me some advice on how to debug this?

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