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Diffstat (limited to 'Documentation/staging/tee.rst')
| -rw-r--r-- | Documentation/staging/tee.rst | 34 |
1 files changed, 32 insertions, 2 deletions
diff --git a/Documentation/staging/tee.rst b/Documentation/staging/tee.rst index 4d4b5f889603..498343c7ab08 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 ============== @@ -225,7 +255,7 @@ The following picture shows a high level overview of AMD-TEE:: +--------------------------+ +---------+--------------------+ At the lowest level (in x86), the AMD Secure Processor (ASP) driver uses the -CPU to PSP mailbox regsister to submit commands to the PSP. The format of the +CPU to PSP mailbox register to submit commands to the PSP. The format of the command buffer is opaque to the ASP driver. It's role is to submit commands to the secure processor and return results to AMD-TEE driver. The interface between AMD-TEE driver and AMD Secure Processor driver can be found in [6]. @@ -260,7 +290,7 @@ cancel_req driver callback is not supported by AMD-TEE. The GlobalPlatform TEE Client API [5] can be used by the user space (client) to talk to AMD's TEE. AMD's TEE provides a secure environment for loading, opening -a session, invoking commands and clossing session with TA. +a session, invoking commands and closing session with TA. References ========== |