Extend the RPMsg structs to accommodate for the introduction of new
backends and contextually fix the ipc_rpmsg_static_vrings_mi backend
(the only user).
Rework also some comments and ipc_service glue code.
Signed-off-by: Carlo Caione <ccaione@baylibre.com>
As know, an instance is the representation of a physical communication
channel between two domains / CPUs.
This communication channel must be usually known and initialized (that
is "opened") by both parties in the communication before a proper
communication can be instaurated using endpoints.
Depending on the backend and on the library / protocol used by the
backend, this "opening" can go through some handshaking or
synchronization procedure run by the parties that sometimes can be
blocking or time-consuming.
For example in the simplest case of a backend using OpenAMP, the remote
side of the communication is waiting for the local part to be up and
running by loop-waiting on some flag set in the shared memory by the
local party.
This is a blocking process so a particular attention must be paid to
where this is going to be placed in the backend code.
Currently it is only possible to have this synchronization procedure in
two points: (1) the init function of the instance, (2) during
ipc_service_register_endpoint().
It should be highly discouraged to put any blocking routine in the init
code, so (1) must be excluded. It is also frowned upon using the
endpoint registration function (2) because the synchronization is
something concerning the instance, not the single endpoints.
This patch is adding a new optional ipc_service_open_instance() function
that can be used to host the handshaking or synchronization code between
the two parties of the instance.
Signed-off-by: Carlo Caione <ccaione@baylibre.com>
The IPC service code is currently assuming that only one IPC instance
does exist and the user can use the IPC service API to interface with
that singleton instance.
This is a huge limitation and this patch is trying to fix this
assumption introducing three major changes to the IPC service API:
- All the IPC instances are now supposed to be instantiated as a struct
device. A new test is introduced to be used as skeleton for all the
other backends.
- ipc_service_register_backend() is now removed (because multiple
backends are now supported at the same time).
- All the other ipc_service_*() functions are now taking a struct device
pointer as parameter to specify on which instance the user is going to
act and operate.
In this patch the documentation is also extended to better clarify the
terminology used.
Signed-off-by: Carlo Caione <ccaione@baylibre.com>
IPC Service allow plugging in different transport backends.
Specifies a generic API that is implemented by the backend.
Signed-off-by: Marcin Jeliński <marcin.jelinski@nordicsemi.no>
