MPC5121e, MBX driver, pvr.ko ...

MPC5121e, MBX driver, pvr.ko ...

[David Jander]

Hi all,

I have a custom board with a MPC5121e (rev 1.5) on it. It is the latest git 
kernel from denx ads5121 head with our BSP mixed in.

I decided to try out Application Note AN3793 from Freescale (3D Graphics on 
the ADS512101 Board Using OpenGL ES).

I started trying to load the provided (binary!) kernel modules into our 
kernel, but I am geeting errors inserting the modules using 
insmod: 'clcdc.ko' complains about not being able to register de device major 
number, and 'dbgdrv.ko' oopses with a BUG() in percpu_modfree()! This 
function should never be called in a non-SMP kernel, so I suspect there are 
some important differences between the kernel I have and the one the 
binary-only drivers where built against :-(

In another approach I managed to load the provided kernel binary (which is 
built for the ADS512101 evaluation board) on our platform, by tweaking our 
device-tree until it booted without crashing. In the end I was able to load 
all the modules and run the OpenGL-ES demo programs.
I can't believe this is the intended way of doing this, so I'd like to know if 
there is someone else who has managed to get the MBX running OpenGL-ES on a 
custom board with a custom build of the kernel.

Note: the kernel version number is still the same: 2.6.24.6, only difference 
AFAIK is some minor unrelated patches to drivers for other MPC5121 SoC 
devices, and probably some different configuration options. Apparently this 
is enough to break binary compatibility for the drivers :-(

Any hint is appreciated...

Best regards,

-- 
David Jander
Protonic Holland.

Re: MPC5121e, MBX driver, pvr.ko ...

[Klaus Pedersen]

[-- Attachment #1: Type: text/plain, Size: 2444 bytes --]

Hi David

I'm also run on a custom board, and using the MBX. 

You need to get the device tree file right. You will see the MBX reserved 
the irq 66 in the boot printout.
Instead of using insmod use modprobe. The are 2 versions of rc.pvr.

Best Regard
Klaus Pedersen

I a early thread about memcpy for G2/G3 cores, you mentioned that you will 
have a look at the init. of the dram controller and the prio-manager, did 
that give you anything??





David Jander <david.jander@protonic.nl> 
Sent by: linuxppc-dev-bounces+kau=bang-olufsen.dk@ozlabs.org
06-02-2009 08:53

To
"Linuxppc-dev" <Linuxppc-dev@ozlabs.org>
cc
John Rigby <jrigby@freescale.com>
Subject
MPC5121e, MBX driver, pvr.ko ...







Hi all,

I have a custom board with a MPC5121e (rev 1.5) on it. It is the latest 
git 
kernel from denx ads5121 head with our BSP mixed in.

I decided to try out Application Note AN3793 from Freescale (3D Graphics 
on 
the ADS512101 Board Using OpenGL ES).

I started trying to load the provided (binary!) kernel modules into our 
kernel, but I am geeting errors inserting the modules using 
insmod: 'clcdc.ko' complains about not being able to register de device 
major 
number, and 'dbgdrv.ko' oopses with a BUG() in percpu_modfree()! This 
function should never be called in a non-SMP kernel, so I suspect there 
are 
some important differences between the kernel I have and the one the 
binary-only drivers where built against :-(

In another approach I managed to load the provided kernel binary (which is 

built for the ADS512101 evaluation board) on our platform, by tweaking our 

device-tree until it booted without crashing. In the end I was able to 
load 
all the modules and run the OpenGL-ES demo programs.
I can't believe this is the intended way of doing this, so I'd like to 
know if 
there is someone else who has managed to get the MBX running OpenGL-ES on 
a 
custom board with a custom build of the kernel.

Note: the kernel version number is still the same: 2.6.24.6, only 
difference 
AFAIK is some minor unrelated patches to drivers for other MPC5121 SoC 
devices, and probably some different configuration options. Apparently 
this 
is enough to break binary compatibility for the drivers :-(

Any hint is appreciated...

Best regards,

-- 
David Jander
Protonic Holland.
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@ozlabs.org
https://ozlabs.org/mailman/listinfo/linuxppc-dev



[-- Attachment #2: Type: text/html, Size: 3740 bytes --]

Re: MPC5121e, MBX driver, pvr.ko ...

[David Jander]

On Friday 06 February 2009 10:03:55 Klaus Pedersen wrote:
> Hi David
>
> I'm also run on a custom board, and using the MBX.
>
> You need to get the device tree file right. You will see the MBX reserved
> the irq 66 in the boot printout.
> Instead of using insmod use modprobe. The are 2 versions of rc.pvr.

Thanks. I'll try that.
Two versions of rc.pvr? Why's that, and where is the other one?

> I a early thread about memcpy for G2/G3 cores, you mentioned that you will
> have a look at the init. of the dram controller and the prio-manager, did
> that give you anything??

Yes it did, and it's a long story, I havn't had persmission to talk about, 
sorry. I believe I can now say that there should be a new errata from 
Freescale explaining it all. As of now it's not on their web-site, but it 
should have been there since last week at least *grrr*.
Btw, it has nothing to do with the prio-manager or the DRAM controller 
whatsoever.

Best regards,

-- 
David Jander
Protonic Holland.

Re: MPC5121e, MBX driver, pvr.ko ...

[Wolfgang Denk]

Dear David,

In message <200902060824.06851.david.jander@protonic.nl> you wrote:
> 
> I decided to try out Application Note AN3793 from Freescale (3D Graphics on 
> the ADS512101 Board Using OpenGL ES).
> 
> I started trying to load the provided (binary!) kernel modules into our 
> kernel, but I am geeting errors inserting the modules using 

The binary kernel modules are a mess. Not  only  they  are  a  pretty
clear  GPL license violation (and I wonder what Freescale is going to
do to sort this out), but it effectively always locks you down to the
specific LTIB kernel version (and probably even to  a  specific  DTS)
they were built against. Open source? Forget it.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de
"Send lawyers, guns and money..."  - Lyrics from a Warren Zevon song

Re: MPC5121e, MBX driver, pvr.ko ...

[David Jander]

On Friday 06 February 2009 20:17:10 Wolfgang Denk wrote:
> Dear David,
>
> In message <200902060824.06851.david.jander@protonic.nl> you wrote:
> > I decided to try out Application Note AN3793 from Freescale (3D Graphics
> > on the ADS512101 Board Using OpenGL ES).
> >
> > I started trying to load the provided (binary!) kernel modules into our
> > kernel, but I am geeting errors inserting the modules using
>
> The binary kernel modules are a mess. Not  only  they  are  a  pretty
> clear  GPL license violation (and I wonder what Freescale is going to
> do to sort this out), but it effectively always locks you down to the

Sorry if this starts to get a little off-topic to this list...
IANAL, so I won't argue about a binary-driver being by definition a 
GPL-violation or not, or if those "gray areas" that Linus mentioned in the 
past, apply in this case.
Besides that, do you have another reason why this is a clear GPL-violation?

> specific LTIB kernel version (and probably even to  a  specific  DTS)
> they were built against. Open source? Forget it.

I never expected this driver to be Open-Source. I always supposed that we'd 
never be able to use the MBX because of this, and use the AXE instead (One of 
our applications needs some form of hardware accelerated image-scaling). But 
since I saw that application note, I couldn't resist trying it out, just to 
see how hard it is to actually use it. The point is made: Leaving aside the 
possible legal implications of the driver's existance, it still is an 
undoable job to get this working in a maintainable fashion.
What could Freescale possibly do about this?... beats me. I don't know about 
the legal implications (again, IANAL), but what if there was a driver like 
NVidia's video drivers (i.e. binary object with a re-compileable shell around 
it to adapt it to other kernels)? Otherwise, I guess Freescale can just as 
well stop making the MPC5121e and just make MPC5123's instead (which 
continues to be an awesome chip nevertheless) :-)

Best regards,

-- 
David Jander
Protonic Holland.