Messages in this thread | | | Date | Tue, 28 May 2013 14:02:27 -0400 | From | Jason Cooper <> | Subject | Re: [PATCH 2/2] net: mv643xx_eth: proper initialization for Kirkwood SoCs |
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Jason,
Sorry, I meant to get back to this earlier and it slipped off of my plate. :(
On Fri, May 24, 2013 at 11:33:06AM -0600, Jason Gunthorpe wrote: > On Fri, May 24, 2013 at 12:46:36PM -0400, Jason Cooper wrote: > > > > Why are you not keen on this? It seems like normal device driver > > > practice, that is what the data field of of_device_id is typically > > > used for.. > > > > I'm not keen on it because we don't have a document saying "All kirkwood > > SoCs need PSC1 set to X after reset." We know it, but have we tested > > the 6282? > > I disagree. The manul is very clear how PSC1 must be set for proper > operation. Clk125BypassEn bit is used only for loopback testing, it > should never set for driver operation. Similarly PortReset must be > cleared for driver operation. > > It is always safe for the driver to clear these bits, if it knows they > are available. In fact, I would argue the driver should always clear > these bits so that the bootloader isn't relied on to do it. It doesn't > matter if the SOC errantly sets the bit or not, it can *always* be > safely cleared.
Great!
> Further, I compared my 88F6282/88F6283 manual against the public > 88F6180/88F619x/88F6281 spec and confirmed that the PSC1 layout is the > same.
Even better.
> So all of these SOC's can share a driver compatible string.
Ok, "marvell,kirkwood-eth" works for me then. I think Sebastian already has patches for that.
> AFAICT the only reason the driver doesn't touch PSC1 today is because > the PSC1 was introduced in a later IP revision and its presence isn't > auto-detectable.
Makes sense.
> The last bit of the puzzle to get bootloader independence on kirkwood > is to encode the phy interface type (GMII/RGMII/BASE-X) in the DT so > the entire PSC1 can be set by the driver..
Hmm, let's work on that separately, and later. I've snowballed this attempt enough ;-)
Thanks for digging into this for us,
Jason.
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