network configuration was: [PATCH 4/4] RTEMS_USE_LWIP option to use lwip in RTEMS

[Gedare Bloom]

On Tue, Apr 20, 2021 at 11:09 AM Sebastian Huber
<sebastian.huber at embedded-brains.de> wrote:
>
> On 12/04/2021 11:56, Robin.Mueller wrote:
>
> > This adds a configuration option if lwIP is used instead of libbsd.
> > It works by specifying RTEMS_USE_LWIP in the config.ini file.
> The RTEMS_* namespace is reserved for RTEMS API parts. Since this is
> BSP-specific, I suggest to rename this option to
> STM32H7_ENABLE_LWIP_SUPPORT.
>

There is still an open question about how/when to configure a specific
networking stack for RTEMS. While we first thought pulling the legacy
stack out of RTEMS will allow configuration after building/installing
RTEMS, it becomes a little challenging maybe to manage the selection
of the networking stack, and there could be advantages (such as this
BSP specific driver alteration) to configure a networking stack at
RTEMS build-time.

To me, it doesn't make any sense that someone will build and install
RTEMS with multiple networking stacks for the same application. The
only exception I might think is some middleware like EPICS. But even
if they do, probably they need some way to partition the stacks, and
we currently don't have a clean separation of the stacks, i.e., there
can be header file name clashes if you tried to install two different
stacks to the same prefix.

I think it makes sense to only allow one networking stack installed to
a prefix. If making that selection is easier/consistent to do at RTEMS
configuration time, then I think we should consider it. Then the
networking stack repo(s) can pluck the configuration variable from the
installed RTEMS, and complain if RTEMS was not configured for that
network stack.

This will obviate any need for BSP-specific configuration variables
for networking stacks, they can just inherit from the top-level config
option.

Gedare