[gPXE-devel] [PATCH] [jme] Adding JMicron Ethernet driver

[Marty Connor]

On 5/31/10 9:08 AM, Guo-Fu Tseng wrote:
> On Sat, 29 May 2010 16:27:55 +0100, Michael Brown wrote
>> Yes.  Take a look at something like drivers/net/b44.c, and the 
>> b44_rx_refill() function.

> In summary, it gPXE will never call poll depend on interrupt.
> I belived it would help on extreme low memory status to modify
> it to the behavior Michael Brown suggested. :)

The driver structure above is common to many gPXE device drivers and is
recommended for the reasons that Michael mentioned and that you have
verified.

One nice feature of the gPXE driver API is its simplicity.  Once you
understand the reasons for some of its design decisions, those decisions
make more sense.

An exercise that I sometimes assign to GSoC students is to do a call
tree by hand for a few gPXE network drivers.

Here are two such call trees done by a GSoC student from last year:

   http://etherboot.org/wiki/soc/2009/asdlkf/notes/rtl8169.c
   http://etherboot.org/wiki/soc/2009/asdlkf/notes/3c90x.c

In particular, please note that in both cases a call to
_refill_rx_ring() occurs in the open() routine and later via _poll().

While one could certainly do such a tree using a software tool ( for an
example see: http://etherboot.org/wiki/doc/codeviz ), I find that doing
them by hand is often more beneficial for new gPXE driver writers.

You have made excellent progress with the JMicron driver, and with this
modification and associated testing we look forward to merging your code
into gPXE soon.

Many thanks for your fine work!

/ Marty /