RE: [ECOS] gdb over ethernet network support for ECOS RAMapplication

[Gary Thomas <gary at chez-thomas dot org>]

On Tue, 2002-06-18 at 11:52, George Sosnowski wrote:
> I was using a target based on powerpc mbx and viper boards which has an
> 860T.
> 
> The thing I'm not clear about is that my ECOS 1.3.1 application is using
> the NET package which is a fuller version IP stack than what Redboot
> has. Do these stacks run concurrently somehow? Or are the ethernet (fec)
> driver and IP stack in the ecos application inheriting the Redboot
> driver and stack?
> 

Actually neither.

The network stacks are split into a logical and physical driver.  Which
logical driver is in use depends on the mode; there is a separate driver
for RedBoot than from an eCos application.  However, the physical driver
is the same for both environments (or at least equivalent).  What happens
is the physical driver in RedBoot is used until the eCos application takes
over.  Once that happens, only the physical driver in the eCos application
is used, but it gets shared by both the eCos stack (xxxBSD based) and the
RedBoot stack.  When there is network activity (incoming packets primarily),
both logical stacks get a chance to process the data/packet.  In this way,
both the eCos stack and the RedBoot stack can run, more or less in tandem.

It's all rather complicated, but it does work, because of how the drivers
are structured.

BTW - I assume you mean by 1.3.1 that you are using anonymous CVS, possibly
before the 2.0 alpha was announced.  I would suggest that you update to the
latest code base since there have been significant changes since 1.3.1 was
officially relased *in March of 2000*!

> -----Original Message-----
> From: Gary Thomas [mailto:gary@chez-thomas.org] 
> Sent: Tuesday, June 18, 2002 10:40 AM
> To: George Sosnowski
> Cc: eCos Discussion
> Subject: Re: [ECOS] gdb over ethernet network support for ECOS
> RAMapplication
> 
> 
> On Tue, 2002-06-18 at 11:20, George Sosnowski wrote:
> > I'm running RedBoot on my target (powerpc 860T based) from flash, 
> > which has both serial and network (TCP 9000) support for GDB. When 
> > RedBoot loads an ECOS
> > (v1.3) RAM
> > application, what's the best way to configure the ecos ram application
> 
> > to have support/ maintain support for GDB over the network/ethernet 
> > (fec) , as well as serial?
> >  
> > >From what I understand it looks like RAM applications are only 
> > >supposed
> > to inherit
> > serial gdb functionality?  Although the Redboot documentation says
> "ecos
> > contains
> > special network sharing code to allow for this situation". I didn't
> > notice anything at the
> > ethernet (fec) or IP stack level. Have I overlooked this? 
> >  
> > One thought I had on doing this was to merge in the Redboot RAM 
> > functionality into
> > my application.  This wouldn't maintain a gdb session over the network
> > from the ROM
> > Redboot, but would give gdb support over the network in RAM
> application
> > at least. 
> 
> If you're running RedBoot from ROM, any network GDB connection will
> remain, even after the eCos application starts up.  One caveat is that
> RedBoot and your eCos application have to use unique IP addresses.  This
> is normally done by giving RedBoot a static address and then letting the
> eCos application either use a different static address or get an address
> dynamically via DHCP.
> 
> Also note that once you start debugging via the network, the serial is
> no longer part of the GDB "path".  Your application can do things with 
> it directly, e.g. by accessing it via the serial device drivers, but 
> only the network will be used for GDB control and/or output.
> 
> What platform are you using (just for my information)?
> 
> 
> -- 
> Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
> and search the list archive: http://sources.redhat.com/ml/ecos-discuss



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