Re: [RFC PATCH 0/9] dt: dependencies (for deterministic driver initialization order based on the DT)

From: Alexander Holler
Date: Wed Aug 27 2014 - 12:31:45 EST


Am 27.08.2014 18:22, schrieb Stephen Warren:
On 08/27/2014 08:44 AM, Catalin Marinas wrote:

It's not just optimisation but an important feature for new arm64 SoCs.
Given some Tegra discussions recently, in many cases the machine_desc
use on arm is primarily to initialise devices in the right order. If we
can solve this in a more deterministic way (other than deferred
probing), we avoid the need for a dedicated SoC platform driver (or
machine_desc) or workarounds like different initcall levels and explicit
DT parsing.

A lot of the ordering is SW driver dependencies. I'm not sure how much
of that can accurately be claimed as HW dependencies. As such, I'm not
sure that putting dependencies into DT would be a good idea; it doesn't
feel like HW data, and might well change if we restructure SW. It'd need
some detailed research though.

Almost every phandle is a dependency, so the DT is already full with them.
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