re(4) (was: Re: playing with qemu's 8139 nic and FreeBSD (loopback mode missing?))

[Cc'ing glebius_at_ because he did most of the recent re(4) commits, and
-current in case possible other driver developers didn't see this thread
in -emulation]

On Wed, May 03, 2006 at 07:46:07AM +0400, Igor Kovalenko wrote:
> Juergen Lock wrote:
> > On Sat, Apr 29, 2006 at 10:48:48AM +0400, Igor Kovalenko wrote:
> >> Juergen Lock wrote:
> >>> On Fri, Apr 28, 2006 at 08:25:02PM +0400, Igor Kovalenko wrote:
> >>>> Juergen Lock wrote:
> >>>>> I played with
> >>>>> 	qemu -monitor stdio -m 256 -cdrom 6.1-RC1-i386-disc1.iso -usb -soundhw es1370 -kernel-kqemu -net nic,model=rtl8139 -net user
> >>>>> and got it as far as
> >>>>> 	re0: diagnostic failed, failed to receive packet in loopback mode
> >>>>> (followed by a panic :) with the (experimental) patches below.
> >>>>>
> >>>>>  Anyone in the mood to implement loopback mode for this nic?
> >>>>>
> >>>>>  Hmm actually...  I just found the original posting in the archive,
> >>>>> is C+ mode implemented now?  If not re is probably not what I want,
> >>>> The rtl8139 is set up with PCI rev ID 0x20 which should be enough for OS driver
> >>>> to detect C+ mode features. C+ mode is OK, tested with Linux driver.
> >>> Cool, so I want FreeBSD's re driver.  That one checks TxConfig
> >>> tho, as changed in my patch (inside #if 0).  And when changed,
> >>> it still doesn't work as mentioned above because the driver expects
> >>> loopback mode to be working.
> >>>>> but the rl driver that it attaches without that #if 0'd (now) hunk
> >>>>> below doesnt seem to be able to get data thru either and I get
> >>>>> 	rl0: watchdog timeout
> >>>>> in dmesg, which usually means the driver doesnt receive interrupts.
> >>>>>
> >>>>>  What the heck, I'll append a log of a run just doing in fixit->cdrom:
> >>>>> 	ifconfig rl0 10.0.2.15
> >>>>> and then exiting (which is enough to trigger the watchdog timeout...)
> >>>>>
> >>>> I'm too lasy to test with fresh freebsd installation :)
> >>>  No need to install FreeBSD, you can get away by just using
> >>> fixit mode of an install iso, i.e. disc1.  (which actually is
> >>> what I did above. :)
> >>>
> >>>  You can look at 6.1RC's re driver here:
> >>> http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/dev/re/if_re.c?annotate=1.46.2.14
> >>>  which includes:
> >>> http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/pci/if_rlreg.h?annotate=1.51.2.3
> >>>
> >>>  And 6.1RC disc1 iso is e.g. here:
> >>> ftp://ftp.ru.freebsd.org:/pub/FreeBSD/ISO-IMAGES-i386/6.1/6.1-RC1-i386-disc1.iso
> >>>
> >>>
> >> Thanks, that iso pointer made it.
> >>
> >  :)
> > 
> >> Please try the following on top of your patch, at least ping should now work:
> > 
> >  Thanks, that seems to get the rl driver going.  Now to fix C+ mode
> > (re driver) change the #if 0 in my patch to #if 1...
> > 
> > 
> 
> I believe freebsd re driver is somewhat broken, e.g. it does not follow documented
> procedure to detect hardware features (e.g. 8139 c+ mode)

Hmm, a bit of googling didn't reveal docs about this, do you have
a pointer?  (I only found the data sheet at
	http://people.freebsd.org/~wpaul/RealTek/spec-8139cp(150).pdf
which doesnt seem to mention detecting c+ hardware specifically)

>  and in tries to use 8169
> registers (e.g. 0xda) on 8139 hardware etc.

 Oh, then it must have mis-detected the nic as a 8169 because
the code in question reads:

        if (sc->rl_type == RL_8169)
                CSR_WRITE_2(sc, RL_MAXRXPKTLEN, 16383);
> 
> Therefore some action from driver people is needed; I can provide a patch which
> enables board timer in rtl8139 emulation (and thus enables hardware timeout
> events) if you need it.

 Yeah I guess that would be useful...