[ECOS] RedBoot and interrupts

Mark Salter msalter@redhat.com
Wed Feb 12 21:41:00 GMT 2003


>>>>> Grant Edwards writes:

> I've got an Intel IXP425 eval board that runs RedBoot.  The 425
> has two built-in Ethernet interfaces, but RedBoot will only use
> a third EEPRO-100 PCI board. Upon investigating the use of the
> two onboard Ethernet interfaces, it seems it is not practical
> to operate the built-in Ethernet controlelrs in polled mode.

> What sort of problems are to be expected if an Ethernet driver
> uses interrupts under RedBoot?

There will be problems with the gdb stub. The stub relies on
interrupts being turned off by the master enable in the CPSR.
If you needed interrupts for the stub comm channel, then that
enable in the CPSR would need to allow interrupts. This would
also allow interrupts used by the program being debugged. This
could complicate the debugging because gdb assumes that the
program being debug is completely stopped when say a breakpoint
is hit. It would also prevent you from being able to debug
interrupt handlers.

I think it best to use the eepro board or to use polling with
the builtin ports.

--Mark

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