Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932578AbbKMDWv (ORCPT ); Thu, 12 Nov 2015 22:22:51 -0500 Received: from mail.kernel.org ([198.145.29.136]:40740 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932404AbbKMDWt (ORCPT ); Thu, 12 Nov 2015 22:22:49 -0500 MIME-Version: 1.0 In-Reply-To: References: <1447345490-29671-1-git-send-email-peter.maydell@linaro.org> <20151112213343.GA28588@rob-hp-laptop> From: Rob Herring Date: Thu, 12 Nov 2015 21:22:27 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2] Documentation: dt: Add bindings for Secure-only devices To: Peter Maydell Cc: Mark Rutland , "devicetree@vger.kernel.org" , Pawel Moll , Ian Campbell , lkml - Kernel Mailing List , Roy Franz , arm-mail-list , Kumar Gala , Jens Wiklander , Christoffer Dall , Grant Likely Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3087 Lines: 62 On Thu, Nov 12, 2015 at 3:42 PM, Peter Maydell wrote: > On 12 November 2015 at 21:33, Rob Herring wrote: >> On Thu, Nov 12, 2015 at 04:24:50PM +0000, Peter Maydell wrote: >>> The existing device tree bindings assume that we are only trying to >>> describe a single address space with a device tree (for ARM, either >>> the Normal or the Secure world). Some uses for device tree need to >>> describe both Normal and Secure worlds in a single device tree. Add >>> documentation of how to do this, by adding extra properties which >>> describe when a device appears differently in the two worlds or when >>> it only appears in one of them. >>> >>> The binding describes the general principles for adding new >>> properties describing the secure world, but for now we only need a >>> single new property, "secure-status", which can be used to annotate >>> devices to indicate that they are only visible in one of the two >>> worlds. >>> >>> The primary expected use of this binding is for a virtual machine >>> like QEMU to describe the VM layout to a TrustZone aware firmware >>> (which would then use the secure-only devices itself, and pass the DT >>> on to a kernel running in the non-secure world, which ignores the >>> secure-only devices and uses the rest). >>> >>> Signed-off-by: Peter Maydell >> >> I'd specifically like Mark's ack on this one. >>> +The general principle of the naming scheme for Secure world bindings >>> +is that any property that needs a different value in the Secure world >>> +can be supported by prefixing the property name with "secure-". So for >>> +instance "secure-reg" would override "reg". If there is no "secure-" >> >> I'd prefer this be "secure-foo" and "foo", rather than reg given I >> specifically have a differing opinion on how to support reg. >> >> Also, would it be secure-vendor,foo or vendor,secure-foo for properties >> with vendor prefix? The latter looks more correct to me, but the former >> would be easier to search for both variants of the property. I'd lean >> towards the latter. > > OK, so how about making that para read: > > + The general principle of the naming scheme for Secure world bindings > + is that any property that needs a different value in the Secure world > + can be supported by prefixing the property name with "secure-". So for > + instance "secure-foo" would override "foo". For property names with > + a vendor prefix, the Secure variant of "vendor,foo" would be > + "vendor,secure-foo". If there is no "secure-" property then the Secure > + world value is the same as specified for the Normal world by the > + non-prefixed property. However, only the properties listed below may > + validly have "secure-" versions; this list will be enlarged on a > + case-by-case basis. Looks good. Rob -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/