On 11/06/2015 05:19 AM, Stefan Roese wrote:
+Stephan Warren & Thomas Chou
On 06.11.2015 13:08, Simon Glass wrote:
+Stefan
Hi Mugunthan,
On 4 November 2015 at 07:25, Mugunthan V N mugunthanvnm@ti.com wrote:
Based on the OF_TRANSLATE Kconfig description, this is required only on platforms with complex "ranges" in the DT nodes. For simpler platforms using SIMPLE_BUS should be sufficient. Since this a set to default y, simple bus is never used in any platform. So make the default value as "n" and enable OF_TRANSLATE only on required platform.
How do you know it is not used? This is surprising because Stefan presumably added it to fix something.
I assume Mugunthan meant, that simple bus is never used. This is not quite correct, as its at least used per default in the SPL (because of size reasons).
And yes, this translation via fdt_translate_address() is needed. At least for some platforms, like mvebu & nios2 (IIRC). Stephen also made some quite striking comments about this a few weeks ago. And I really think that we should make use of this function per default. Platforms that know for sure that they don't need this functionality can always disable it selectively.
Mugunthan, why do you want to disable this functionality? Does it cause problems on your platform? If yes, which ones?
Processing of ranges is a fundamental part of handling DT in general. It should be enabled by default. If there are well-researched cases where (a) including the code is problematic (e.g. due to code size restrictions) and (b) someone is watching the DTs processed on those platforms like a hawk to ensure no ranges properties are introduced into the DT, *then* we could make a special-case exception to disable the feature in those specific cases. As such, I think enable-by-default, disable-when-chosen is the appropriate default.