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

Hi Juergen,

Juergen Lock wrote:
> On Sun, May 07, 2006 at 12:38:06AM +0400, Igor Kovalenko wrote:
>> Hi Juergen,
>>
>> Juergen Lock wrote:
>>> [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)
>> Well, I might have misread some docs; please do not consider this as an 
>> assault :)
>> I remember PCI rev id >= 0x20 is C+ mode for realtek 8139.
> 
> I don't.  It may well be the doc you saw this in just is no longer
> online, or I didn't came up with the right search terms...
>>>> 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);
> 
>  And with your patch i get
> 	RTL8139: not implemented write(b) addr=0xda val=0x00
> but that can't be this line anyway because it seems to be a byte access...
> Any of the re(4) experts have an idea where this comes from?
> (log generated by defining DEBUG_RTL8139 in the patched hw/rtl8139.c)
> 

I see the re driver actually is doing 2 byte write at RL_TXSTART so the second
byte goes to RL_MAXRXPKTLEN. Comment in if_rlreg.h says RL_TXSTART is 8bit
so this is a bug in if_re.c line 2063

This is not affecting qemu's card emulation (the extra byte write is ignored)
so I think the problem is somewhere else.

-- 
Kind regards,
Igor V. Kovalenko