On Thu, Sep 06, 2012 at 10:14:06AM +0100, Will Deacon wrote: > On Thu, Sep 06, 2012 at 10:09:14AM +0100, Simon Horman wrote: > > Hi Will, > > > > On Thu, Sep 06, 2012 at 10:01:28AM +0100, Will Deacon wrote: > > > Hi guys, > > > > > > On Thu, Sep 06, 2012 at 04:29:02AM +0100, Simon Horman wrote: > > > > On Wed, Sep 05, 2012 at 03:34:09PM +0100, Matthew Leach wrote: > > > > > Also, I use a > > > > > different segment for the dtb rather than appending it to the > > > > > zImage; I think this approach would be better as it is less > > > > > restrictive, however a kernel patch is required to set r2 to the > > > > > appropriate address on entry to the new kernel. What are your > > > > > thoughts? > > > > > > > > I would prefer to avoid requiring kernel changes unless necessary - > > > > the kernels some of the boards I work with require DT since 3.5. > > > > However, I am happy to discuss this further, there certainly is > > > > merit to a clean implementation. > > > > > > I had a quick look at both the approaches and it looks like Matthew requires > > > changes to the host kernel (to load the dtb correctly) and Simon requires > > > changes to the target kernel (to pick up the dtb correctly). > > > > Could you explain a little why you feel my patch requires a change to > > the target kernel? > > Sure, I may be misunderstanding something, so please shout if that's the > case! Anyway, I was under the impression that you required > CONFIG_ARM_APPENDED_DTB to be enabled in the target so that it can pick up > the new DT. If that's not the case, then you'll need to change the host > kernel to fix up r2 (rather than point it at the KEXEC_ARM_ATAGS_OFFSET, > which is too small for a dtb). Thanks. It was not my intention that CONFIG_ARM_APPENDED_DTB is required, though due to limitations of the bootloader on the board I was using I did have that option enabled for the host kernel. Thanks for pointing out the size issue with using KEXEC_ARM_ATAGS_OFFSET, I had overlooked that. I think the best way forward, as both you and Matt suggested earlier, is to modify the host kernel.
