[SLOF] [PATCH slof] fdt: Fix creating new nodes at H_CAS

[Greg Kurz]

On Wed, 29 Jan 2020 18:46:03 -0600
Segher Boessenkool <segher at kernel.crashing.org> wrote:

> On Thu, Jan 30, 2020 at 10:09:56AM +1100, Alexey Kardashevskiy wrote:
> > On 29/01/2020 22:33, Greg Kurz wrote:
> > >> Instead, this changes new nodes creation. At pass#0 when we copy phandles
> > >> from the FDT update blob to SLOF, we create new nodes with all
> > >> new properties and call "finish-device" only after all properties are
> > >> copied to the new nodes. At this point we particularly care about "reg"
> > >> as this is the unit address which SLOF parses for us and sets the unit
> > >> address in "finish-device"; we could skip other properties for later
> > > 
> > > "finish-device" only sets the first entry of the "reg" property as a
> > > fallback. This will be an issue when we start seeing new nodes with
> > > bigger unit values (eg, a new PHB).
> 
> finish-device should never change (or create or delete or whatever) any
> property.  It should finish up the device node, and that's that.
> 

Sorry I mis-phrased. "finish-device" sets the unit name according to
the only the first entry of  "reg". It doesn't changes any property.

> > > The setting of the unit from "reg" is actually handled by
> > > "fdt-unflatten-node" which calls "fdt-reg-unit":
> > > 
> > >       2dup s" reg" str= IF
> > >           2swap 2dup fdt-reg-unit 2swap
> > >       THEN
> > > 
> > > Something similar could be done...
> > 
> > Huh. Should not we then fix "finish-device"?
> 
> This whole unit-address setting thing is an implementation detail in SLOF,
> it's an optimisation.  It should be kept pretty much invisible.
> 

Is this a suggestion to consolidate most if not all of the unit address
setting in one place instead of adding _yet_ another guy that does it ?

> > > This doesn't address the case of a hotplug-over-hotplug since the
> > > new parent node doesn't have a "decode-unit" method, but at least
> > > it covers all cases where the parent node was created at boot time.
> 
> If a bus node has no decode-unit, you get problems.  Big problems.
> 

Yeah I saw that when I tried to hotplug a PCI device on a hotplugged PHB.

> 
> Segher