On Mon, Nov 16, 2015 at 11:01:10AM -0600, Rob Herring wrote:

On Thu, Oct 29, 2015 at 09:21:25AM +0100, Jens Wiklander wrote:

quoted

Introduces optee prefix and adds bindings for ARM TrustZone based OP-TEE
implementation.

Signed-off-by: Jens Wiklander <redacted>
---
 .../bindings/arm/firmware/optee,optee-tz.txt       | 29 ++++++++++++++++++++++
 .../devicetree/bindings/vendor-prefixes.txt        |  1 +
 2 files changed, 30 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/firmware/optee,optee-tz.txt

diff --git a/Documentation/devicetree/bindings/arm/firmware/optee,optee-tz.txt b/Documentation/devicetree/bindings/arm/firmware/optee,optee-tz.txt
new file mode 100644
index 0000000..0a8ed0d
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/firmware/optee,optee-tz.txt

@@ -0,0 +1,29 @@
+OP-TEE Device Tree Bindings
+
+OP-TEE is a piece of software using hardware features to provide a Trusted
+Execution Environment. The security can be provided with ARM TrustZone, but
+also by virtualization or a separate chip. As there's no single OP-TEE
+vendor we're using "optee" as the first part of compatible property,
+indicating the OP-TEE protocol is used when communicating with the secure
+world.
+
+* OP-TEE based on ARM TrustZone required properties:
+
+- compatible     : should contain "optee,optee-tz"

I would leave off optee as a vendor. Different implementations by 
vendors should then add their vendor prefix as they all have the chance 
to screw-up something. I suppose we could do "linaro" as the reference 
implementation.

OK, I'll use "linaro" then.

quoted

+
+- method         : The method of calling the OP-TEE Trusted OS. Permitted
+                   values are:
+
+                   "smc" : SMC #0, with the register assignments specified
+		           in drivers/tee/optee/optee_smc.h
+
+                   "hvc" : HVC #0, with the register assignments specified
+		           in drivers/tee/optee/optee_smc.h

The use here would be a guest VM calling thru to hypervisor and then 
hypervisor calling optee?

Yes, the hypervisor needs to be involved (translating IPA to PA etc)
when invoking secure world.

quoted

+
+
+
+Example:
+	optee {

This should go under a /firmware node similar to 
Documentation/devicetree/bindings/arm/firmware/tlm,trusted-foundations.txt.

I tried that and discovered that a
compatible = "simple-bus";
is needed for the firmware node for optee to get probed. Is it OK to write
the example as:

firmware {
        compatible = "simple-bus";

        optee {
...

Thanks,
Jens
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