From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jerome Forissier Subject: [PATCH] Documentation: dt: Add binding for /secure-chosen/stdout-path Date: Fri, 3 Mar 2017 10:24:33 +0100 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: devicetree@vger.kernel.org Cc: mark.rutland@arm.com, peter.maydell@linaro.org, Jerome Forissier , robh+dt@kernel.org, linux-arm-kernel@lists.infradead.org, robin.murphy@arm.com, jens.wiklander@linaro.org, christoffer.dall@linaro.org List-Id: devicetree@vger.kernel.org Some platforms may use a single device tree to describe two address spaces, as described in d9f43babb998 ("Documentation: dt: Add bindings for Secure-only devices"). For these platforms it makes sense to define a secure counterpart of /chosen, namely: /secure-chosen. This new node is meant to be used by the secure firmware to pass data to the secure OS. Only the stdout-path property is supported for now. Signed-off-by: Jerome Forissier --- Documentation/devicetree/bindings/arm/secure.txt | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) v2 - Clarify the expected behavior when /secure-chosen/stdout-path is not present (either the property or the node itself), as proposed by Peter and Robin. Note that I have made the fallback to /chosen optional. diff --git a/Documentation/devicetree/bindings/arm/secure.txt b/Documentation/devicetree/bindings/arm/secure.txt index e31303f..c4a818e 100644 --- a/Documentation/devicetree/bindings/arm/secure.txt +++ b/Documentation/devicetree/bindings/arm/secure.txt @@ -32,7 +32,8 @@ describe the view of Secure world using the standard bindings. These secure- bindings only need to be used where both the Secure and Normal world views need to be described in a single device tree. -Valid Secure world properties: +Valid Secure world properties +----------------------------- - secure-status : specifies whether the device is present and usable in the secure world. The combination of this with "status" allows @@ -51,3 +52,19 @@ Valid Secure world properties: status = "disabled"; secure-status = "okay"; /* S-only */ status = "disabled"; /* disabled in both */ status = "disabled"; secure-status = "disabled"; /* disabled in both */ + +The secure-chosen node +---------------------- + +Similar to the /chosen node which serves as a place for passing data +between firmware and the operating system, the /secure-chosen node may +be used to pass data to the Secure OS. Only the properties defined +below may appear in the /secure-chosen node. + +- stdout-path : specifies the device to be used by the Secure OS for + its console output. The syntax is the same as for /chosen/stdout-path. + If the /secure-chosen node exists but the stdout-path property is not + present, the Secure OS should not perform any console output. If + /secure-chosen does not exist, the Secure OS may use the value of + /chosen/stdout-path instead (that is, use the same device as the + Normal world OS). -- 2.7.4