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

[Anselm M. H. <an...@ho...>]

Hello Timothy,

TL> So far I have been merely brave enough download some of the USB Specs.
TL> Any thoughts on what would be required, the practicality of porting the
TL> Linux code, etc.  With the limited number of usb NICS (most are Pegasus
TL> based I believe)

There seem to be several wireless USB models out there. Having kind of
"usb stack" could simplify implementation of those.

TL> would implementing a full usb subsystem make sense, or
TL> would implementing the required code within the driver itself be more
TL> desirable.

I'm no pro on usb implementations, but I remember there are two or
three different drivers for USB chipsets in the linux kernel. Just for
this fact, hardware abstraction could make sense.

Another idea: For some time, there has been (never tested, only read
about it) support to have multiple-driver-etherboot-files, especially
useful for floppy-boot. Imagine the case there are four or five
USB-drivers on it, that made a lot of reinitializations necessary. Not
quite senseful, IMHO.

My line of thought:
Make a switch "WITHUSB" for initialization of USB mainboard
ressources. This one should be as hardware independant as possible,
having in best cast support for UHCI and OHCI (what was EHCI the
acronym for?), so ALI and INTEL.... chipsets.
Then read in a list of (I believe this is somehow possible) USB-IDs
hanging on the bus. Store this list somewhere in RAM. That should have
been done when initializing etherboot.
When a USB driver is loaded (which lies within 3 seconds mostly, so no
too great risk someone would unplug the network device just in that
moment), it just checks for any USB-IDs it is capable of handling.

Important step: When exiting etherboot (no matter where and to where
it is exited), the USB device probably MUST be uninitialized. That's a
task, to find all that exit points :-) (probably Ken and Eric did a
well job there as everywhere and doc'ed it in the source, Luke)

Would be quite interesting. Keep us posted.

TL> Any comments would be most welcome.

TL> Tim Legge

Best regards,
 Anselm                            mailto:an...@ho...


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