[Qemu-devel] Qemu and Linux 2.4

[Qemu-devel] Qemu and Linux 2.4

[Vlad Lungu]

I know some of you will laugh, but:

- QEMU malta emulation is not really complete, to put it mildly
- the QEMU target is available only for Linux 2.6
- despite popular opinion, 2.4 ain't dead yet, at least in the embedded 
market


I have a port of the QEMU target for Linux 2.4.34.4 (latest 2.4 kernel 
on linux-mips.org), with NE2000 card working (in both BE and LE modes).
Still rough at the edges, but it works on stock qemu-0.9.0 with -M mips.

If anyone is interested, I can send the patch by e-mail. I have no idea 
if I can post attachments to the list(s), that's why it's not attached.

Vlad

Re: [Qemu-devel] Qemu and Linux 2.4

[Thiemo Seufer]

Vlad Lungu wrote:
> I know some of you will laugh, but:
>
> - QEMU malta emulation is not really complete, to put it mildly

Out of curiosity, what parts did you miss?

> - the QEMU target is available only for Linux 2.6
> - despite popular opinion, 2.4 ain't dead yet, at least in the embedded 
> market
>
>
> I have a port of the QEMU target for Linux 2.4.34.4 (latest 2.4 kernel on 
> linux-mips.org), with NE2000 card working (in both BE and LE modes).
> Still rough at the edges, but it works on stock qemu-0.9.0 with -M mips.

I recommend to improve the Qemu Malta emulation, and make it work with
2.4 Malta kernels. (ISTR it used to work, so it shouldn't need a lot to
get there.)


Thiemo

Re: [Qemu-devel] Qemu and Linux 2.4

[Vlad Lungu]

Thiemo Seufer wrote:
> Vlad Lungu wrote:
>> I know some of you will laugh, but:
>>
>> - QEMU malta emulation is not really complete, to put it mildly
> 
> Out of curiosity, what parts did you miss?

Like, for example, the PCI stuff. So I can use the network card.
And yes, I am aware of YAMON.

>> - the QEMU target is available only for Linux 2.6
>> - despite popular opinion, 2.4 ain't dead yet, at least in the embedded 
>> market
>>
>>
>> I have a port of the QEMU target for Linux 2.4.34.4 (latest 2.4 kernel on 
>> linux-mips.org), with NE2000 card working (in both BE and LE modes).
>> Still rough at the edges, but it works on stock qemu-0.9.0 with -M mips.
> 
> I recommend to improve the Qemu Malta emulation, and make it work with
> 2.4 Malta kernels. (ISTR it used to work, so it shouldn't need a lot to
> get there.)

I'm sure that improving the Qemu Malta emulation is a very noble goal, 
but for people that need a working 2.4 kernel NOW, my patch could be 
useful. Having the QEMU target in 2.6 surely helped me.

Vlad

Re: [Qemu-devel] Qemu and Linux 2.4

[Alexander Voropay]

<vlad@comsys.ro> wrote:

>>> - QEMU malta emulation is not really complete, to put it mildly
>> Out of curiosity, what parts did you miss?
> Like, for example, the PCI stuff. So I can use the network card.

 PCI stuff in the QEMU/Malta works fine, but pseudo-bootrom
does not perform PCI enumeration and leaves uninitialized PCI BARs.

 Linux MIPS/Malta 2.4 can not perform PCI enumeration too.  The LANCE
Ethernet driver *requres* a pre-initialized BARs. The situation even worse,
since current Linux 2.4 can't be even built with NEW_PCI and PCI_AUTO
options at all (due to linkage error).

http://www.linux-mips.org/wiki/PCI_Subsystem

 There is the same PCI problem with NetBSD/evbmips and seems VxWorks/Malta.

> And yes, I am aware of YAMON.

 AFAIK, YAMON may runs on the MIPS hardware only, and may not
be redistribuded in the source or binary form.

 Anyway, YAMON binary does not work on the Qemu/Malta. The Galileo
chip is far more complicated then Qemu emulation. It contains four DMA
channels, four timers e.t.c. e.t.c.

>> I recommend to improve the Qemu Malta emulation, and make it work with
>> 2.4 Malta kernels. (ISTR it used to work, so it shouldn't need a lot to
>> get there.)
> 
> I'm sure that improving the Qemu Malta emulation is a very noble goal, 
> but for people that need a working 2.4 kernel NOW, my patch could be 
> useful. Having the QEMU target in 2.6 surely helped me.

 The only thing we need is a good bootrom (BIOS) for the MIPS/Malta
(Free-YAMON ;)

 As a quick'n'disty solution you could initialize PCI BARs of the
device number 12 (0x0b, LANCE) with GDB:

(gdb) set variable {int}0xbbe00cf8=0x80005810   <--- I/O address
(gdb) set variable {int}0xbbe00cfc=0x00002001
(gdb) set variable {int}0xbbe00cf8=0x80005814  <--- Mem address
(gdb) set variable {int}0xbbe00cfc=0xfc200000
(gdb) set variable {int}0xbbe00cf8=0x80005804  <--- Enable Mem and I/O
(gdb) set variable {int}0xbbe00cfc=0x00000003
(gdb) set variable {int}0xbbe00cf8=0x8000583c   <---- IRQ=10 tied to Pin A
(gdb) set variable {int}0xbbe00cfc=0xff06010a
(gdb) cont
Continuing.

...
Linux version 2.4.35.3 (alec@ilias.nwpi.ru) (gcc version 3.3.6) #2 Tue Sep 25 18:59:10 MSD 2007
...
pcnet32.c:v1.30h 06.24.2004 tsbogend@alpha.franken.de
pcnet32: PCnet/PCI II 79C970A at 0x2000, 52 54 00 12 34 56 assigned IRQ 10.
eth0: registered as PCnet/PCI II 79C970A
pcnet32: 1 cards_found.
...

# lspci -v
....
00:0b.0 Class 0200: 1022:2000 (rev 10)
        Flags: bus master, fast devsel, latency 64, IRQ 10
        I/O ports at 2000 [size=32]
        Memory at fc200000 (32-bit, non-prefetchable) [size=32]


# ifconfig eth0 192.168.1.1 netmask 255.255.255.0 up
#
# ping 192.168.1.1
PING 192.168.1.1 (192.168.1.1): 56 data bytes
64 bytes from 192.168.1.1: icmp_seq=0 ttl=64 time=4.2 ms



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Re: [Qemu-devel] Qemu and Linux 2.4

[Ralf Baechle]

On Wed, Sep 26, 2007 at 08:25:18PM +0400, Alexander Voropay wrote:

> >>>- QEMU malta emulation is not really complete, to put it mildly
> >>Out of curiosity, what parts did you miss?
> >Like, for example, the PCI stuff. So I can use the network card.
> 
> PCI stuff in the QEMU/Malta works fine, but pseudo-bootrom
> does not perform PCI enumeration and leaves uninitialized PCI BARs.
> 
> Linux MIPS/Malta 2.4 can not perform PCI enumeration too.  The LANCE
> Ethernet driver *requres* a pre-initialized BARs. The situation even worse,
> since current Linux 2.4 can't be even built with NEW_PCI and PCI_AUTO
> options at all (due to linkage error).
> 
> http://www.linux-mips.org/wiki/PCI_Subsystem
> 
> There is the same PCI problem with NetBSD/evbmips and seems VxWorks/Malta.

Both CONFIG_PCI_NEW and PCI_AUTO were amazingly broken in both concept
and implementation.  It is possible to get them to work well for particular
configurations but for the general case nothing else nothing but rewrite
can rescue things.

> >And yes, I am aware of YAMON.
> 
> AFAIK, YAMON may runs on the MIPS hardware only, and may not
> be redistribuded in the source or binary form.

Alchemy boards run YAMON, too.

> *******************************************************************************************************
> This message and any attachments (the "message") are confidential and 
> intended solely for the addressees. Any unauthorised use or dissemination 

Soley for all the billion internet users, I assume ;-)

  Ralf

Re: [Qemu-devel] Qemu and Linux 2.4

[Vlad Lungu]

Ralf Baechle wrote:
> 
> Both CONFIG_PCI_NEW and PCI_AUTO were amazingly broken in both concept
> and implementation.  It is possible to get them to work well for particular
> configurations but for the general case nothing else nothing but rewrite
> can rescue things.
> 

Hi Ralf,

I found this the hard way :-(

BTW, what's the status on the latest 2.4 patch I sent you?

Vlad

Re: [Qemu-devel] Qemu and Linux 2.4

[Blue Swirl]

On 9/26/07, Alexander Voropay <alec@nwpi.ru> wrote:
> <vlad@comsys.ro> wrote:
>
> >>> - QEMU malta emulation is not really complete, to put it mildly
> >> Out of curiosity, what parts did you miss?
> > Like, for example, the PCI stuff. So I can use the network card.
>
>  PCI stuff in the QEMU/Malta works fine, but pseudo-bootrom
> does not perform PCI enumeration and leaves uninitialized PCI BARs.
>
>  Linux MIPS/Malta 2.4 can not perform PCI enumeration too.  The LANCE
> Ethernet driver *requres* a pre-initialized BARs. The situation even worse,
> since current Linux 2.4 can't be even built with NEW_PCI and PCI_AUTO
> options at all (due to linkage error).
>
> http://www.linux-mips.org/wiki/PCI_Subsystem
>
>  There is the same PCI problem with NetBSD/evbmips and seems VxWorks/Malta.
>
> > And yes, I am aware of YAMON.
>
>  AFAIK, YAMON may runs on the MIPS hardware only, and may not
> be redistribuded in the source or binary form.
>
>  Anyway, YAMON binary does not work on the Qemu/Malta. The Galileo
> chip is far more complicated then Qemu emulation. It contains four DMA
> channels, four timers e.t.c. e.t.c.
>
> >> I recommend to improve the Qemu Malta emulation, and make it work with
> >> 2.4 Malta kernels. (ISTR it used to work, so it shouldn't need a lot to
> >> get there.)
> >
> > I'm sure that improving the Qemu Malta emulation is a very noble goal,
> > but for people that need a working 2.4 kernel NOW, my patch could be
> > useful. Having the QEMU target in 2.6 surely helped me.
>
>  The only thing we need is a good bootrom (BIOS) for the MIPS/Malta
> (Free-YAMON ;)

Someone could port OpenBIOS or LinuxBIOS to MIPS.

Re: [Qemu-devel] Qemu and Linux 2.4

[Vlad Lungu]

Blue Swirl wrote:
> 
> Someone could port OpenBIOS or LinuxBIOS to MIPS.
> 

Well, just FYI:

I sort-of-ported U-Boot to Qemu (-M mips). Network performance sucks for 
some reason (hard enough that tftp-booting a kernel is impossible) and I 
didn't have time to investigate this yet. But I guess that porting to 
(-M malta) should not be that hard, and I think there is some PCI 
support already in U-boot.

Vlad

[Qemu-devel] U-Boot

[Vlad Lungu]

Vlad Lungu wrote:

lol, replying to myself

> Blue Swirl wrote:
> 
>>
>> Someone could port OpenBIOS or LinuxBIOS to MIPS.
>>
> 
> Well, just FYI:
> 
> I sort-of-ported U-Boot to Qemu (-M mips). Network performance sucks for 
> some reason (hard enough that tftp-booting a kernel is impossible) and I 
> didn't have time to investigate this yet. But I guess that porting to 
> (-M malta) should not be that hard, and I think there is some PCI 
> support already in U-boot.
> 

Reports of poor network performance have been greatly exagerated. 
Apparently, what it happens is :

- qemu doesn't respond with a next-server or server-name in DHCP, apparently
- U-Boot uses broadcast in this case as the server address
- things don't quite work

Setting IP by hand or using tap for networking and configuring DHCP on 
the host correctly allows loading bt TFTP (or even nfs-booting with 
tap). I can boot a vmlinux with embedded ramdisk (a couple of Megs) in 
maybe 10 seconds. Still getting RX timeouts, but it's no big deal.

I will polish the thing a little and post an update in 1-2 weeks max.
Maybe we can have a bootrom for MIPS shipping with Qemu, after all. Even 
for malta.

Vlad

Re: [Qemu-devel] Qemu and Linux 2.4

[Vlad Lungu]

Alexander Voropay wrote:
> <vlad@comsys.ro> wrote:
> 
>>>> - QEMU malta emulation is not really complete, to put it mildly
>>> Out of curiosity, what parts did you miss?
>> Like, for example, the PCI stuff. So I can use the network card.
> 
> PCI stuff in the QEMU/Malta works fine, but pseudo-bootrom
> does not perform PCI enumeration and leaves uninitialized PCI BARs.
> 
> Linux MIPS/Malta 2.4 can not perform PCI enumeration too.  The LANCE
> Ethernet driver *requres* a pre-initialized BARs. The situation even worse,
> since current Linux 2.4 can't be even built with NEW_PCI and PCI_AUTO
> options at all (due to linkage error).
> 
> http://www.linux-mips.org/wiki/PCI_Subsystem
> 
> There is the same PCI problem with NetBSD/evbmips and seems VxWorks/Malta.

Well, that's a pretty big showstopper, don't you think?

[snip]
> The only thing we need is a good bootrom (BIOS) for the MIPS/Malta
> (Free-YAMON ;)
> 
> As a quick'n'disty solution you could initialize PCI BARs of the
> device number 12 (0x0b, LANCE) with GDB:
> 
> (gdb) set variable {int}0xbbe00cf8=0x80005810   <--- I/O address
> (gdb) set variable {int}0xbbe00cfc=0x00002001
> (gdb) set variable {int}0xbbe00cf8=0x80005814  <--- Mem address
> (gdb) set variable {int}0xbbe00cfc=0xfc200000
> (gdb) set variable {int}0xbbe00cf8=0x80005804  <--- Enable Mem and I/O
> (gdb) set variable {int}0xbbe00cfc=0x00000003
> (gdb) set variable {int}0xbbe00cf8=0x8000583c   <---- IRQ=10 tied to Pin A
> (gdb) set variable {int}0xbbe00cfc=0xff06010a
> (gdb) cont
> Continuing.

That's dirty alright, but not exactly quick. You kind of need gdb :-)

Vlad

[Qemu-devel] Re: Qemu and Linux 2.4

[ralf]

On Tue, Sep 11, 2007 at 03:31:31PM +0300, Vlad Lungu wrote:

> I know some of you will laugh, but:
> 
> - QEMU malta emulation is not really complete, to put it mildly
> - the QEMU target is available only for Linux 2.6
> - despite popular opinion, 2.4 ain't dead yet, at least in the embedded 
> market

It very much is for new product development.  It's a long time that I've
seen any 2.4-based development being started for new MIPS platforms.  I
basically get zero feedback for 2.4.

The last patch submitted for 2.4 was on 2006-06-15 by Chris Dearman btw.
Everything else since was just backported fixes from newer kernels and I've
given up on that give the overwhelming feedback I keep receiving for 2.4.

> I have a port of the QEMU target for Linux 2.4.34.4 (latest 2.4 kernel 
> on linux-mips.org), with NE2000 card working (in both BE and LE modes).
> Still rough at the edges, but it works on stock qemu-0.9.0 with -M mips.

Actually 2.4.35.2 / 2.4.36-pre1 are the latest.

> If anyone is interested, I can send the patch by e-mail. I have no idea 
> if I can post attachments to the list(s), that's why it's not attached.

I do take Linux 2.4 patches provided they don't destabilize the 2.4 branch.
The few remaining user expect stability, not a Penguin action movie ;-)
But aside of that, same submission guidelines as for 2.6.

Cheers,

  Ralf