Re: [PATCH 4/8] arm: link a device tree blob into the xen image

[David Vrabel <david.vrabel@citrix.com>]

On 10/02/12 16:50, Tim Deegan wrote:
> At 13:52 +0000 on 10 Feb (1328881958), Ian Campbell wrote:
>> On Fri, 2012-02-10 at 13:40 +0000, David Vrabel wrote:
>>> On 10/02/12 13:35, Ian Campbell wrote:
>>>> On Fri, 2012-02-10 at 13:03 +0000, David Vrabel wrote:
>>>>> From: David Vrabel <david.vrabel@citrix.com>
>>>>>
>>>>> Link a device tree blob (DTB) into the xen image.  This is loaded
>>>>> immediately after Xen and xen_start() is called with the correct
>>>>> address in atag_paddr.
>>>>
>>>> Is platform.dtb supposed to be included in this patch/series or is it
>>>> intended that I should supply it from somewhere? (in which case, how and
>>>> where etc).
>>>
>>> I make a symlink to vexpress-v2p-aem-v7a.dtb built in my Linux tree.
>>>
>>> Would it be better build the DTB from source included in Xen?
>>
>> I guess that's what Linux has done but I don't know if we want to
>> replicate all that and keep syncing etc. On the flip side I suppose it's
>> currently only a single platform.
> 
> I think we should take it into our tree in some form, unless there's a
> way to automatically extract it from the dom0 kernel at boot.  It should
> be possible to recompile Xen without needing to configure and build a
> linux kernel.

I'm going to take the device trees out of the kernel and put them in a
separate repository.  The DTB can be built independantly of Xen and
Linux and easily hacked on for local changes (e.g., to change the
Xen/Linux command lines).

You will be able to specify the DTB to include in Xen by setting the DTB
make variable (either on the command line or in .config).

This sound ok?

> In theory this will eventually be provided by the bootloader or
> firmware, right?

Yes.

David