linux-kernel - Re: [PATCH v9 3/7] ata: libahci: allow to use multiple PHYs

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Date:	Tue, 8 Jul 2014 17:40:10 -0400
From:	Tejun Heo <tj@...nel.org>
To:	Antoine Ténart 
	<antoine.tenart@...e-electrons.com>
Cc:	sebastian.hesselbarth@...il.com, kishon@...com,
	alexandre.belloni@...e-electrons.com,
	thomas.petazzoni@...e-electrons.com, zmxu@...vell.com,
	jszhang@...vell.com, linux-arm-kernel@...ts.infradead.org,
	linux-ide@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, Hans de Goede <hdegoede@...hat.com>
Subject: Re: [PATCH v9 3/7] ata: libahci: allow to use multiple PHYs

Hey,

On Tue, Jul 08, 2014 at 07:49:00PM +0200, Antoine Ténart wrote:
> > So, yeah, it's being used both as input and output and we also have
> > the arguments which affect port_map, right?  It does seem confusing.
> 
> I do see priv->port_map as being automatically set and then restricted
> if needed by the port_map input here. I don't see how that's confusing.
> The only modification is we restrict the port_map parameter to the set
> of available ports. The port_map argument affected priv->port_map before
> this patch.

It is confusing.  If you wanna pass around available ports in hpriv,
please add a separate field and replace the arguments to
save_initial_config().

> > Well, so does clk.  Let's say clk is more restricted and phy can be
> > one or more per port and thus needs to be dynamic.  If so, shouldn't
> > we at least have some correlation between phys and ports?  It bothers
> > me that now libahci is carrying random number of resources that it has
> > no idea how to associate with the ports it manages.  What if later we
> > want to involve phy driver in power managing unoccupied ports?
> 
> I see. This is a first (working) attempt to have a one node per port. I
> agree that would be nice to have a correlation between ports and PHYs.
> This can definitively be added when needed without changing the dt
> bindings as only the internal representation changes. This would also
> require to get all phys from the port nodes, which is again internal
> stuff.
> 
> Don't you think we can go by steps, and have a following up series for
> this when needed (like in a power managing series for unoccupied ports)?

I don't know.  It isn't exactly difficult to make it per-port, is it?
We already have ahci_port_priv and wouldn't the code actually be
simpler that way?

Thanks.

-- 
tejun
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