Messages in this thread | | | Date | Thu, 07 Nov 2013 10:45:58 +0100 | From | Alexander Sverdlin <> | Subject | Re: [PATCH 0/3 - V2] Introducing Device Tree Overlays |
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Hi!
On 06/11/13 20:08, ext Pantelis Antoniou wrote: >>> The following patchset introduces Device Tree overlays, a method >>> of dynamically altering the kernel's live Device Tree, along with >>> a generic interface to use it in a board agnostic manner. >> >> In case this has been discussed and I missed it: Why are we doing this? >> Isn't it possible to d o the overlay thingy in u-boot and pass a >> complete device tree to the kernel? >> Are you trying to do something like hotplug-PCI where the PCI card can >> be replaced at runtime? >> > > It has been discussed. > > We are doing it because > > a) We tried to do it in u-boot and it has been a complete disaster. > Regular users just can't handle bootloader updates.
There are buses we simply do not want to deal with in uboot, like SRIO, PCIe, everything-over-ethernet. All of them are hot-pluggable. And yeah, device-tree processing in uboot is possible, but in Linux it's way easier...
> b) It is similar to that. It was originally created for the beaglebone, > which has a concept of capes (similar to Arduino shields). > http://circuitco.com/support/index.php?title=BeagleBone_Capes > Turns out it's really useful to anyone doing reconfigurable hardware too, > so that's why FPGA people are thinking of using it. > > c) There are people that want to tinker with Linux based hardware boards > but are not kernel developers. This gives them a way to do so without > having to recompile the kernel and/or reboot while tinkering. > >> Sebastian > > Regards > > -- Pantelis > > >
-- Best regards, Alexander Sverdlin.
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