libbsd - BSP Bus Hook Up Help Please! :)

Sebastian Huber sebastian.huber at embedded-brains.de
Tue Jul 3 18:56:30 UTC 2012


Hi,

On 03/07/12 20:10, Joel Sherrill wrote:
> Hi
>
> Jennifer and I have tracked the current problem down
> to when the fxp driver attempts to alloc a bus resource.
> It (correctly) gets to legacy_pcib_alloc_resource()
> in pci_bus.c around line 541. That calls
> bus_generic_alloc_resource() which (I think) fails because
> there is no BSP Bus code hooked.

this is due to the kobj(9) objects:

http://www.freebsd.org/cgi/man.cgi?query=kobj

The resource management is very generic in FreeBSD.  I don't know if we 
really need this in RTEMS.

>
> In the libbsdport code, the entire bus code was replaced
> with code that only knew PCI. I think this code is sufficient
> for now as our "generic BSP bus" code. But I can't seem
> to figure out how the FreeBSD PC code set this up.
>
> On top of that, we currently have the bus routines inlined
> as memory access operations. That is wrong for x86.

Yes, we can do this similar to FreeBSD:

http://svnweb.freebsd.org/base/head/sys/x86/include/bus.h?revision=216592&view=markup

The key point is that compile time constant tags are optimized.

>
> I am sure we need a bus driver hooked in and we are missing
> the link and magic.
>
> Help appreciated.
>


-- 
Sebastian Huber, embedded brains GmbH

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