From 63d5bc420f460162cc5318136c2bddba87cfbb29 Mon Sep 17 00:00:00 2001 From: Jens Wiklander Date: Tue, 15 Jun 2021 22:23:44 +0200 Subject: docs: staging/tee.rst: add a section on OP-TEE notifications Adds a section on notifications used by OP-TEE, synchronous and asynchronous. Reviewed-by: Sumit Garg Acked-by: Marc Zyngier Signed-off-by: Jens Wiklander --- Documentation/staging/tee.rst | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) (limited to 'Documentation') diff --git a/Documentation/staging/tee.rst b/Documentation/staging/tee.rst index 4d4b5f889603..3c63d8dcd61e 100644 --- a/Documentation/staging/tee.rst +++ b/Documentation/staging/tee.rst @@ -184,6 +184,36 @@ order to support device enumeration. In other words, OP-TEE driver invokes this application to retrieve a list of Trusted Applications which can be registered as devices on the TEE bus. +OP-TEE notifications +-------------------- + +There are two kinds of notifications that secure world can use to make +normal world aware of some event. + +1. Synchronous notifications delivered with ``OPTEE_RPC_CMD_NOTIFICATION`` + using the ``OPTEE_RPC_NOTIFICATION_SEND`` parameter. +2. Asynchronous notifications delivered with a combination of a non-secure + edge-triggered interrupt and a fast call from the non-secure interrupt + handler. + +Synchronous notifications are limited by depending on RPC for delivery, +this is only usable when secure world is entered with a yielding call via +``OPTEE_SMC_CALL_WITH_ARG``. This excludes such notifications from secure +world interrupt handlers. + +An asynchronous notification is delivered via a non-secure edge-triggered +interrupt to an interrupt handler registered in the OP-TEE driver. The +actual notification value are retrieved with the fast call +``OPTEE_SMC_GET_ASYNC_NOTIF_VALUE``. Note that one interrupt can represent +multiple notifications. + +One notification value ``OPTEE_SMC_ASYNC_NOTIF_VALUE_DO_BOTTOM_HALF`` has a +special meaning. When this value is received it means that normal world is +supposed to make a yielding call ``OPTEE_MSG_CMD_DO_BOTTOM_HALF``. This +call is done from the thread assisting the interrupt handler. This is a +building block for OP-TEE OS in secure world to implement the top half and +bottom half style of device drivers. + AMD-TEE driver ============== -- cgit v1.3-18-gd494 From ff5fdc34d0aed9931c01e6d50f7f873ecf8df8d3 Mon Sep 17 00:00:00 2001 From: Jens Wiklander Date: Tue, 15 Jun 2021 22:23:48 +0200 Subject: dt-bindings: arm: optee: add interrupt property Adds an optional interrupt property to the optee binding. Reviewed-by: Sumit Garg Reviewed-by: Rob Herring Acked-by: Marc Zyngier Signed-off-by: Jens Wiklander --- .../devicetree/bindings/arm/firmware/linaro,optee-tz.yaml | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.yaml b/Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.yaml index c24047c1fdd5..9a426110a14a 100644 --- a/Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.yaml +++ b/Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.yaml @@ -24,6 +24,12 @@ properties: compatible: const: linaro,optee-tz + interrupts: + maxItems: 1 + description: | + This interrupt which is used to signal an event by the secure world + software is expected to be edge-triggered. + method: enum: [smc, hvc] description: | @@ -42,10 +48,12 @@ additionalProperties: false examples: - | + #include firmware { optee { compatible = "linaro,optee-tz"; method = "smc"; + interrupts = ; }; }; -- cgit v1.3-18-gd494