Re: [PATCH v3 09/10] xen: arm: update multiboot device tree bindings.

[Julien Grall <julien.grall@linaro.org>]

On 07/21/2014 01:18 PM, Ian Campbell wrote:
> On Mon, 2014-07-21 at 12:53 +0100, Julien Grall wrote:
>> On 07/21/2014 12:45 PM, Ian Campbell wrote:
>>> On Fri, 2014-07-18 at 22:03 +0100, Julien Grall wrote:
>>>> Hi Ian,
>>>>
>>>> On 18/07/14 14:08, Ian Campbell wrote:
>>>>> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
>>>>
>>>> Acked-by: Julien Grall <julien.grall@linaro.org>
>>>
>>> Thanks. I've applied patches 1..9 of this series. I'll resend 10 ASAP
>>> with the change you've suggested.
>>>
>>> On my potential backports list I've got:
>>> xen: arm: implement generic multiboot compatibility strings
>>> xen: arm: /chosen/module@N/bootargs bootprotcol node is not deprecated
>>>
>>> I don't think anything else here is suitable for backport. Let me know
>>> if you think something is (or isn't)
>>
>> I would also update the document bindings in
>> docs/misc/arm/device-tree/booting.txt.
>>
>> The patch #9 looks the good one for this purpose. Minus the unspecified
>> type example.
> 
> I think it is acceptable to point people to the latest version of the
> doc in the dev branch as the canonical copy.
> 
> The latest version already needs to properly describe the mechanisms for
> backwards compatibility anyway and trying to backport only the docs
> updates which match backported bits of code is liable to get fiddly
> quite fast and/or require new patches etc, I'd rather not do this.
> 
>> BTW, I don't find anything in the documentation talking about bootmodule
>> type detection by ordering. Is this intended?
> 
> No, I should have done this and forgot, thanks for the reminder. See
> below.
> 
> Ian.
> 
> 8<--------------------------
> 
> From f9e80ead57b9f739c3041fe5abc4b23c8f0eb18f Mon Sep 17 00:00:00 2001
> From: Ian Campbell <ian.campbell@citrix.com>
> Date: Mon, 21 Jul 2014 13:16:31 +0100
> Subject: [PATCH] xen: arm: document boot module compatibility based on
>  ordering
> 
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> ---
>  docs/misc/arm/device-tree/booting.txt |    8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/docs/misc/arm/device-tree/booting.txt b/docs/misc/arm/device-tree/booting.txt
> index d967061..ad98bf3 100644
> --- a/docs/misc/arm/device-tree/booting.txt
> +++ b/docs/misc/arm/device-tree/booting.txt
> @@ -23,7 +23,13 @@ Each node contains the following properties:
>  	compatible string (if one applies) in addition to the generic
>  	string (which must always be present).
>  
> -        Xen 4.4 supported a different set of legacy compatible strings
> +	Xen will assume that the first module which lacks a more

With this change, it's not clear that Xen 4.4 doesn't support boot
module ordering. I would precise Xen 4.5 and onwards.

With that:

Acked-by: Julien Grall <julien.grall@linaro.org>

> +	specific compatible string is a "multiboot,kernel" and that
> +	the second such is a "multiboot,ramdisk". Any subsequent
> +	modules which lack a specific compatiblity string will not
> +	receive any special treatment.
> +
> +	Xen 4.4 supported a different set of legacy compatible strings
>  	which remain supported such that systems supporting both 4.4
>  	and later can use a single DTB.
>  
> 

Regards,


-- 
Julien Grall