adding device driver kernel module for xen/linux

adding device driver kernel module for xen/linux

[Fajar A. Nugraha]

Hi,

I wanted to add a kernel module (bcm5700, device driver for Broadcom 
network adapter) to linux 2.6, xen-3.0.0. Is it possible to use the 
kernel module (source) as-is, without modifications, or do I need to 
edit the module source code to be Xen-specific?

I noticed that the files tg3.c and tg3.h on linux-2.6.12-xen is the same 
as the one on pristine-linux-2.6.12, so presumably, no change is needed. 
However, using bcm5700 module on linux-2.6.12-xen kernel doesn't work, 
while using bcm5700 on native linux (on the same machine) works.

Regards,

Fajar

RE: adding device driver kernel module for xen/linux

[Ian Pratt]

> I wanted to add a kernel module (bcm5700, device driver for 
> Broadcom network adapter) to linux 2.6, xen-3.0.0. Is it 
> possible to use the kernel module (source) as-is, without 
> modifications, or do I need to edit the module source code to 
> be Xen-specific?

The code should not need to be modified.
 
> I noticed that the files tg3.c and tg3.h on linux-2.6.12-xen 
> is the same as the one on pristine-linux-2.6.12, so 
> presumably, no change is needed. 
> However, using bcm5700 module on linux-2.6.12-xen kernel 
> doesn't work, while using bcm5700 on native linux (on the 
> same machine) works.

The tg3 driver certainly works for me. When you say native, do you mean
2.6.12 native? Perhaps you have a very new version of the chip that
needs a more recent driver?

Perhaps more likely, you may have an interrupt routeing issue. Does the
NIC appear to be using the same interrupt number in both the native and
xen cases?

Ian 

Re: adding device driver kernel module for xen/linux

[Fajar A. Nugraha]

Ian Pratt wrote:

>>I wanted to add a kernel module (bcm5700, device driver for 
>>Broadcom network adapter) to linux 2.6, xen-3.0.0. Is it 
>>possible to use the kernel module (source) as-is, without 
>>modifications, or do I need to edit the module source code to 
>>be Xen-specific?
>>    
>>
>
>The code should not need to be modified.
> 
>  
>
>>I noticed that the files tg3.c and tg3.h on linux-2.6.12-xen 
>>is the same as the one on pristine-linux-2.6.12, so 
>>presumably, no change is needed. 
>>However, using bcm5700 module on linux-2.6.12-xen kernel 
>>doesn't work, while using bcm5700 on native linux (on the 
>>same machine) works.
>>    
>>
>
>The tg3 driver certainly works for me. When you say native, do you mean
>2.6.12 native? 
>
My native linux uses redhat's official kernel (2.6.9).

>Perhaps you have a very new version of the chip that
>needs a more recent driver?
>
>  
>
It is possible. I used xen-2.0.7 on hardware with revision number 2, and 
it works. However, broadcom hardware with revision number 10 (bought 
mid-2005) doesn't work with xen-2.0.7 nor xen-3.0.0. Or to be more 
specific :

-   using bcm5700 (broadcom's official driver, until 1-16-2006) : 
doesn't work, even when xend is not running
-   using tg3 (from Xen's stock 2.6.12 kernel and broadcom's current 
official driver) : works without xend, but doesn't work if I use xend in 
the default bridge configuration.

>Perhaps more likely, you may have an interrupt routeing issue. Does the
>NIC appear to be using the same interrupt number in both the native and
>xen cases?
>
>  
>
No, they're using different interrupt numbers.

On native Linux, they use interrupts 209 and 217 (I have two network cards).
On Xen (with both tg3 and bcm5700 driver), they use interrupts 77 and 78.

Should the different interrupt numbers make a difference?

Regards,

Fajar

Re: adding device driver kernel module for xen/linux

[Jon Mason]

On Tue, Jan 17, 2006 at 12:54:39PM +0700, Fajar A. Nugraha wrote:
> Hi,
> 
> I wanted to add a kernel module (bcm5700, device driver for Broadcom 
> network adapter) to linux 2.6, xen-3.0.0. Is it possible to use the 
> kernel module (source) as-is, without modifications, or do I need to 
> edit the module source code to be Xen-specific?

It should be possible to compile the bcm5700 source in the Xen linux
tree, but using a binary module isn't a good idea.  Also, bcm5700 has
been abandoned in favor of tg3, and the Broadcom developers working on
bcm5700 have migrated most of their changes from this driver into tg3.

Thanks,
Jon

> 
> I noticed that the files tg3.c and tg3.h on linux-2.6.12-xen is the same 
> as the one on pristine-linux-2.6.12, so presumably, no change is needed. 
> However, using bcm5700 module on linux-2.6.12-xen kernel doesn't work, 
> while using bcm5700 on native linux (on the same machine) works.
> 
> Regards,
> 
> Fajar
> 
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