Re: [Etherboot-developers] USB NICs and Etherboot RFC

[Michael B. <mb...@fe...>]

On 4 Jan 2003, Eric W. Biederman wrote:
> > Being a sucker for punishment and the owner of an unsupported NIC, the
> > Pegasus based Linksys adapter, I keep giving some thought to what would
> > be required to implement USB support for Etherboot.
> > So far I have been merely brave enough download some of the USB Specs.
> > Any thoughts on what would be required, the practicality of porting the
> > Linux code, etc.  With the limited number of usb NICS (most are Pegasus
> > based I believe) would implementing a full usb subsystem make sense, or
> > would implementing the required code within the driver itself be more
> > desirable.
> > Any comments would be most welcome.
> I think implementing the required code as a usb subsystem is a reasonable
> way to go.  usb is a lot like pci so all of the plug and play goodies
> for detecting which nic to use come into play.  So it should
> be reasonably clean.

Seconded.  Having a multiple-bus infrastructure would also make it easier
to add PCMCIA support in the future.

FWIW, I thought about adding PCMCIA support a few months back.  My
strategy was going to be to start by adding ISAPNP support to the core of
Etherboot (using the code currently in 3c515.c), since 16-bit PCMCIA
devices look pretty much like ISAPNP devices once you have initialised
them.  I'm guessing that the overall structure should be something like:
  a) Scan all known buses for bus adapters.
  b) Initialise any bus adapters found and add new buses to list of known
     buses.
  c) Repeat steps (a) & (b) until no new adapters are found (this is
     necessary to cope with the case of e.g. a PCMCIA USB adapter).
  d) Scan all known buses for network devices - similar to the PCI scan
     that now takes place but more general.

Michael Brown
http://www.fensystems.co.uk