Messages in this thread | | | Date | Fri, 18 Oct 2013 12:32:29 -0700 | From | Michael Bohan <> | Subject | Re: [PATCH] of/lib: Export fdt routines to modules |
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On Fri, Oct 18, 2013 at 09:30:32AM -0700, David Daney wrote: > On 10/18/2013 08:57 AM, Rob Herring wrote: > [...] > > > >Unflattening is definitely the right > >direction to go here. > > > > I wonder if that is really true. > > The device tree in question is very short lived, and used to control > the configuration of some hardware device when loading the driver. > > The use of it is completely contained within a single driver (at > least that is my understanding), it is not information that needs to > be shared system wide.
That's correct.
> Given that it is a driver implementation issue, rather than making > things work nicely system wide, I don't think it really matters what > is done. > > It may be that the overhead of unflattening the tree and then > freeing it, is much greater than just extracting a few things from > the FDT.
Yes, this was my original thought as well. On the other hand, having libfdt in the kernel does add a little extra bloat, and so it seems a tradeoff from one-time runtime overhead to footprint.
> That said, I don't really have a preference for what is done. My > original questions were targeted at understanding this particular > use case.
My preference is probably straight libfdt calls, but if others think that unpacking is a better solution, I'm able to go that route as well. My only concern there is that we provide a means to detect invalid dtb image (ex. handle error codes) and also free the device_node allocations once the device is released.
Thanks, Mike
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