Subject: Re: Trivial cleanup in ocp_uart.c

From: Scott Anderson <[email-masked]>
Date: Wed, 26 Jun 2002 10:27:01 -0700

David Gibson wrote:
> Basically there are two quite distinct approaches either of which
> would make sense (for any given peripheral/bus type):
>         a) Register each device as it is discovered.  Register each
> driver as the appropriate module loads.  Whenever either event happens
> the common code calls init or probe callbacks in a driver to connect
> it to any devices of appropriate type.
>         b) No registration.  When a driver loads, it searches for all
> devices of appropriate type, and initializes each of them in turn.
>
> Examples of (a) include the new PCI interface, PCMCIA, and the 2.5
> unified device model.  Examples of (b) include the old PCI interface
> (pci_find_device()) and (some?/all?) non-PCI devices on OF machines
> (e.g. Airport).
>
> Approach (a) is clearly needed to handle hotplug.  But that's not an
> issue for OCPs (indeed device (not driver) registration will always be
> degenerate) so either approach would do.  Frankly (a) seems overkill
> for OCPs, but it does have the advantage of being easily integrated
> into the unified device model.

I wouldn't be quite so quick to dismiss the issue of hotplug from OCP.
I have heard rumblings of people having FPGAs with on-chip processors
wanting to reprogram the FPGAs on the fly with different sets of
peripherals.

    Scott Anderson
    [email-masked]   MontaVista Software Inc.
    (408)328-9214               1237 East Arques Ave.
    http://www.mvista.com       Sunnyvale, CA  94085

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