Using partitions in (Arcnet) device drivers?

[Bill Butler]

Thanks Ian I was just surprised to see you show concern {:-0

Another way to get your memory is to get a region from a large region
pool. I'm not sure this has much of an advantage unless you delete and
create the partitions often. Actually I'm considering creating 1 or 2
large regions and then use the Region Manager to handle the majority of
my memory. Maybe I'm just too much from the old school which says
embedded and allocs don't mix. Currently I use these 2 constructs to
create a very efficient Buffer pool for passing messages in queues.

Bill Butler
Project Lead
Sr Software Engineer
AIPCOM Inc
(972) 644-2328 (x16)

> -----Original Message-----
> From: Ian Caddy [mailto:ianc at microsol.iinet.net.au]
> Sent: Wednesday, June 26, 2002 9:28 PM
> To: Bill Butler
> Cc: 'rtems list'; JOHNSON, Mac -Syntegra UK
> Subject: Re: Using partitions in (Arcnet) device drivers?
> 
> Hi Bill,
> 
> Sorry, I didn't mean to scare you...;-)
> 
> I wasn't trying to bring into question the reliability of partitions,
I
> was just wondering why I didn't see their use in the RTEMS core.  Joel
> has explained that for me.
> 
> I was also a bit worried about how I was going to set aside memory for
> the partition and that I wanted to be able to change it size
(possibly)
> on startup of the unit from a previously downloaded configuration.
> 
> I got my answer for this from Mac Johnson, that we just need to work
out
> the size, then alloc the block off the heap, I don't know why but I
> hadn't even thought of using the heap in this way.  It is so
simple....
> I thought I was going to have to set aside a chunk of memory before I
> created the heap or any other region for my partition and then I was
> concerned about being able to change it at a later startup.
> 
> Now I can just create the heap as now with the max size and get all my
> partitions from it.  It is so much simpler.
> 
> Thanks for the offer of the BSP Bill, but ours is also looking in
pretty
> good shape at this stage, I just need to get this last driver
completed
> and then we will be ready to port over our old SOS based 68000
> application environment into this lovely open source system.
> 
> Talk to you soon,
> 
> Ian Caddy
> 
> 
> Bill Butler wrote:
> 
> >Ian,
> >
> >EEK!.. I'm currently writing code that I rely on Partitions heavily
-- I
> >am using the SPxx test code as examples and trust that it works.
> >
> >Also, Ian, I have a pretty good BSP for the 5307 if you want it. It
is
> >not 100% complete but it's close. One thing that might be a
limitation
> >is it does not initialize SDRam, because my code runs in SDram and
that
> >would kind of be a trick to initial what I'm already relying on :).
> >
> >If you want it let me know.
> >
> >
> >
> >Bill Butler
> >Project Lead
> >Sr Software Engineer
> >AIPCOM Inc
> >(972) 644-2328 (x16)
> >
> >
> >
> >>-----Original Message-----
> >>From: Ian Caddy [mailto:ianc at microsol.iinet.net.au]
> >>Sent: Wednesday, June 26, 2002 12:56 AM
> >>To: rtems list
> >>Subject: Using partitions in (Arcnet) device drivers?
> >>
> >>Hi All,
> >>
> >>We are in the process of putting an arcnet device driver into our
> >>
> >>
> >RTEMS
> >
> >
> >>BSP for the Coldfire 5307.
> >>
> >>By the end of it, we hope to have the Arcnet device driver
supporting
> >>both the legacy packet interface of an existing product but at the
> >>
> >>
> >same
> >
> >
> >>time putting a layer in so we can use IP over the Arcnet also.
> >>
> >>Our Arcnet is configured to only have 256 byte packets, and we need
> >>somewhere to put them when they are received.
> >>
> >>We have two options available to us, the first is to get the number
of
> >>buffers required off the heap and then manage them ourselves.
> >>
> >>The second option is to create partition for the buffers and then
let
> >>RTEMs manage the buffers for us.
> >>
> >>We are working on the 4.5.0 release of RTEMs and I did a quick
search
> >>through the tree and no-one in the RTEMs system seems to use any
> >>partitions.  There are some used in the tests.
> >>
> >>Is there some reason why partitions have not been used, as it looks
> >>
> >>
> >like
> >
> >
> >>exactly what we need for this device driver?
> >>
> >>Also, just a note on the SMC91C111 Ethernet port we were doing.  It
is
> >>complete now with DMA and working well, but I have been dragged off
it
> >>for some time.  I still haven't managed to move it into the libchip
> >>
> >>
> >area
> >
> >
> >>but it is still on my list of things to do.  I just need to make
sure
> >>the Arcnet is running also and then I will get back to it.
> >>
> >>regards,
> >>
> >>
> >>Ian Caddy
> >>
> >>--
> >>
> >>ianc at microsol.iinet.net.au
> >>Microsol (Aust) Pty Ltd
> >>
> >>Phone: (+61) 08 9473 6600
> >>Fax:   (+61) 08 9473 6699
> >>
> >>
> >
> >
> >
> >
> >
> >
> 
> --
> 
> ianc at microsol.iinet.net.au
> Microsol (Aust) Pty Ltd
> 
> Phone: (+61) 08 9473 6600
> Fax:   (+61) 08 9473 6699
>