[PATCH] powernv: Search for new flash DT node location

Michael Ellerman mpe at ellerman.id.au
Thu Aug 4 13:28:04 AEST 2016

Jack Miller <jack at codezen.org> writes:

> On Wed, Aug 03, 2016 at 05:16:34PM +1000, Michael Ellerman wrote:
>> We could instead just search for all nodes that are compatible with
>> "ibm,opal-flash". We do that for i2c, see opal_i2c_create_devs().
>> Is there a particular reason not to do that?
> I'm actually surprised that this is preferred. Jeremy mentioned something
> similar, but I guess I just don't like the idea of finding devices in weird
> places in the tree.

But where is "weird". Arguably "/opal/flash" is weird. What does it
mean? There's a bus called "opal" and a device on it called "flash"? No.

Point being the structure is fairly arbitrary, or at least debatable, so
tying the code 100% to the structure is inflexible. As we have discovered.

Our other option is to tell skiboot to get stuffed, and leave the flash
node where it was on P8.

> Then again, if we can't trust the DT we're in bigger
> trouble than erroneous flash nodes =).

Quite :)

> If we really just want to find compatible nodes anywhere, let's simplify i2c
> and pdev_init into one function and make that behavior consistent with this
> new patch.

That seems OK to me.

We should get an ack from Stewart though for the other node types.


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