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Re: Re: RedBoot "set MAC address" API?
Grant Edwards wrote:
In gmane.os.ecos.general, you wrote:
I've never seen an Ethernet chip with a non-volatile MAC.
Many MACs have an interface for a serial EEPROM from which they fetch
the MAC address and other initialization data automatically on
reset. The manufacturer usually installs the MAC address. Admittedly
this is more common for PCI MAC cards that in embedded devices, but
I've seen it on development boards too.
That's often how it's done on things like PCI and development
boards, but I've never seen it done that way on a "real"
embedded product. Maybe we've always been to cheap to spring
for a separate config ROM for the Ethernet MAC.
The response to this is normally - there's already FLASH or EEPROM
available for other things, why add components? That's why 'fconfig'
is used.
In general the MAC address is stored in the fconfig data. All
drivers that need to set the MAC address contain code to query
the flash and fetch the MAC address from there, or call a
platform-specific function than may do that. They usually also
have a fallback to a compiled-in MAC address.
Except for the drivers I've used, apparently. Is there any
documentation available on how fconfig data is formatted/used?
Look at any of the PowerPC drivers.
I'd recommend using the RedBoot support (macros, functions, etc).
It's pretty straight forward to use.
Better yet, is any of the documentation available in a
searchible format (e.g a pdf file or a single html page)?
Searching for info in documents formatted
one-paragraph-per-web-page is hopeless.
You can always generate this yourself:
% cd .../ecos/doc/sgml
% ./makemakefile
% make pdfa4
-or-
% make pdfletter
--
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Gary Thomas | Consulting for the
MLB Associates | Embedded world
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