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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/sdei.rst | 33 |
1 files changed, 28 insertions, 5 deletions
diff --git a/docs/sdei.rst b/docs/sdei.rst index b81e21a9a..ed6a85abe 100644 --- a/docs/sdei.rst +++ b/docs/sdei.rst @@ -48,8 +48,10 @@ execute the registered handler [10]. The client terminates its execution with original EL2 execution [13]. Note that the SDEI interrupt remains active until the client handler completes, at which point EL3 does EOI [12]. -SDEI events can be explicitly dispatched in response to other asynchronous -exceptions. See `Explicit dispatch of events`_. +Other than events bound to interrupts (as depicted in the sequence above, SDEI +events can be explicitly dispatched in response to other exceptions, for +example, upon receiving an *SError* or *Synchronous External Abort*. See +`Explicit dispatch of events`_. The remainder of this document only discusses the design and implementation of SDEI dispatcher in TF-A, and assumes that the reader is familiar with the SDEI @@ -71,7 +73,8 @@ event descriptors. Both macros take 3 arguments: - The event number: this must be a positive 32-bit integer. -- The interrupt number the event is bound to: +- For an event that has a backing interrupt, the interrupt number the event is + bound to: - If it's not applicable to an event, this shall be left as ``0``. @@ -82,6 +85,17 @@ event descriptors. Both macros take 3 arguments: To define event 0, the macro ``SDEI_DEFINE_EVENT_0()`` should be used. This macro takes only one parameter: an SGI number to signal other PEs. +To define an event that's meant to be `explicitly dispatched`__ (i.e., not as a +result of receiving an SDEI interrupt), the macro ``SDEI_EXPLICIT_EVENT()`` +should be used. It accepts two parameters: + +.. __: `Explicit dispatch of events`_ + +- The event number (as above); + +- Event priority: ``SDEI_MAPF_CRITICAL`` or ``SDEI_MAPF_NORMAL``, as described + below. + Once the event descriptor arrays are defined, they should be exported to the SDEI dispatcher using the ``REGISTER_SDEI_MAP()`` macro, passing it the pointers to the private and shared event descriptor arrays, respectively. Note that the @@ -99,6 +113,8 @@ Regarding event descriptors: - Must be bound to a Secure SGI on the platform. +- Explicit events should only be used in the private array. + - Statically bound shared and private interrupts must be bound to shared and private interrupts on the platform, respectively. See the section on `interrupt configuration`__. @@ -132,8 +148,10 @@ Event flags describe the properties of the event. They are bit maps that can be - ``SDEI_MAPF_BOUND``: Marks the event as statically bound to an interrupt. These events cannot be re-bound at runtime. +- ``SDEI_MAPF_NORMAL``: Marks the event as having *Normal* priority. This is + the default priority. + - ``SDEI_MAPF_CRITICAL``: Marks the event as having *Critical* priority. - Without this flag, the event is assumed to have *Normal* priority. Event definition example ------------------------ @@ -150,6 +168,10 @@ Event definition example /* Dynamic private events */ SDEI_PRIVATE_EVENT(100, SDEI_DYN_IRQ, SDEI_MAPF_DYNAMIC), SDEI_PRIVATE_EVENT(101, SDEI_DYN_IRQ, SDEI_MAPF_DYNAMIC) + + /* Events for explicit dispatch */ + SDEI_EXPLICIT_EVENT(2000, SDEI_MAPF_NORMAL); + SDEI_EXPLICIT_EVENT(2000, SDEI_MAPF_CRITICAL); }; /* Shared event mappings */ @@ -258,7 +280,8 @@ event to be dispatched: - Event 0 can't be dispatched. -- The event must neither be a dynamic event nor be bound to an interrupt. +- The event must be declared using the ``SDEI_EXPLICIT_EVENT()`` macro + described above. - The event must be private to the PE. |