On 08/15/2013 05:52 AM, Dave Martin wrote:

On Tue, Aug 13, 2013 at 11:29:48AM +0900, Alexandre Courbot wrote:

quoted

Trusted Foundations is a TrustZone-based secure monitor for ARM that
can be invoked  using a consistent smc-based API on all supported
platforms. This patch adds initial basic support for Trusted
Foundations using the ARM firmware API. Current features are limited
to the ability to boot secondary processors.

quoted

diff --git a/Documentation/devicetree/bindings/arm/firmware/tl,trusted-foundations.txt b/Documentation/devicetree/bindings/arm/firmware/tl,trusted-foundations.txt

quoted

+Required properties:
+- compatible : "tl,trusted-foundations"
+- version : Must contain the version number string of the Trusted Foundation
+	firmware.

Are you sure there is no low-level way to probe vendor and version info?
If there is, then the DT should describe nothing except the fact that
the probe interface exists.

I also worry that two integrations on different SoCs might have the
same version number, yet still be different due to vendor-specific
features and options.

I would expect HW-specific compatible values also to be present in a DT.
For example, perhaps:

compatible = "tl,trusted-foundations-nvidia-shield",
"tl,trusted-foundations";

(nvidia vendor, shield board/implementation)

This would allow matching on the specific value
"tl,trusted-foundations-nvidia-shield" in the future if some quirking
was needed, but if this wasn't needed, drivers could just bind to the
generic "tl,trusted-foundations".

quoted

+- version : Must contain the version number string of the Trusted Foundation
+	firmware.

Are you sure there is no low-level way to probe vendor and version info?
If there is, then the DT should describe nothing except the fact that
the probe interface exists.

I also worry that two integrations on different SoCs might have the
same version number, yet still be different due to vendor-specific
features and options.

Talking of the version - if we do need to represent this in the DT, how
about 2 separate cells for major/minor version rather than encoding it
into a string? Then, no parsing would be required.