Including new machine type in the kernel configuration

halturata · 09-19-2007, 12:04 PM

Hello,

I'm trying to build a 2.6.20 kernel for a powerpc arch, and when doing a configure I see that there is no support exactly for my board, but rather for an older one. I have the Board support package for my board and my question is how can I include an option in the linux configuration (showing up when I do a 'make menuconfig' for example). I googled aroud but all I find is HOW-TO's for generla kernel compilations. Can you give me some clues about that?

Thanks in advance!

GrapefruiTgirl · 09-20-2007, 05:11 AM

I just did this the other day, to add a driver to my kernel that wasn't there previously. I haven't got the exact docs handy, but here's the basic idea:

1 - place the C sourcecode file into its appropriate subfolder in the kernel source area;
2 - edit the Kconfig file in that subfolder appropriately, to add the driver to menuconfig as an option. Follow the existing examples of similar items in that area.
3 - edit the Makefile in that subfolder also, and add a new 'obj' line somewhere, following the examples of the existing lines, with the object code filename of your code, and necessary arguments.

I think that's pretty much all that needs to be done. Those are the only things I did to add a driver for a hardware monitor chip I have on my board, and it worked great. The item was in menuconfig as it should have been, and it selected and built just fine

halturata · 09-20-2007, 07:07 AM

OK, thanks, I'll give it a try and I'll come back with some results.

Actually I wanted to add a support for a whole new SBC (or maybe sub-architecture is better to say). However I have support for a similar board, which I think will be good starting point.

GrapefruiTgirl · 09-20-2007, 07:30 AM

I agree. Try something small first, and see how it goes. If it works out well, then go for adding more, and keep us posted of the process/progress.
I wonder, why would your configuration not be included in the kernel by default? Perhaps it is a little-used (sub)architecture, or what do you think?

halturata · 09-21-2007, 11:24 AM

Yes, you are right, it is an embedded board, and support for it doesn't come with a vanilla kernel.

Here is what I've tried till now (with no success I must admit):

Code:

1. Addded the board-specific files under linux/arch/ppc/platforms:
# cp ./BSP/mvme6100.c ./BSP/mvme6100.h /usr1/src/linux/arch/ppc/platforms

2. Added this line to the Makefile under linux/arch/ppc/platforms:
obj-$(CONFIG_MVME6100)    += mvme6100.o

3. Added the following lines in Kconfig under linux/arch/ppc:
config MVME6100
        bool "Motorola-MVME6100"

4. Copied a default configuration for the new board into the kernel source tree:
# cp ./BSP/mvme6100_defconfig /usr1/src/linux/arch/ppc/configs

5. Added some additional drivers for onboard hardware under linux/drivers and linux/drivers/custom:
# cp -pr ./BSP/drivers/custom /usr1/src/linux/drivers/custom
# cp -pr ./BSP/drivers/vme /usr1/src/linux/drivers/vme

6. Added to linux/drivers/Kconfig the following lines:
source "drivers/vme/Kconfig"
source "drivers/custom/mv64360_dma/Kconfig"
source "drivers/custom/nvram/Kconfig"
source "drivers/custom/sdd/Kconfig"
source "drivers/custom/watchdog/Kconfig"

7. Added to linux/drivers/Makefile the following lines:
obj-$(CONFIG_VME_BRIDGE)                   += vme/
obj-$(CONFIG_MVME6100_IDMA)                += vme/
obj-$(CONFIG_MVME6100_NVRAM)               += vme/
obj-$(CONFIG_MVME6100_SDD)                 += vme/
obj-$(CONFIG_MVME6100_WATCHDOG)            += vme/

What still bothers me is that I don't know where to include this "CONFIG_MVME*" options so the Kconfig framework can see them. The same goes for the VME driver specific option "CONFIG_VME_BRIDGE". Are they only defined in the platform specific header files (the ones under linux/arch/ppc/platforms)? I mean they are nothing but pure #define statements, or I'm wrong on that?

Any further help an guidance are welcome

GrapefruiTgirl · 09-21-2007, 11:34 AM

Interesting.. Looks like you are going about it the right way, but already you are getting beyond my knowledge level when it comes to custom kernel configging. Personally, I would have gone as far as your STEP-3 above, and tried it to see what happened.

However, you may do better if you present this issue in the new LINUX - HARDWARE sub-forum for EMBEDDED, or in the LINUX - SERVER forum. Maybe rather than rewriting your question, you could post over there a basic intro, and link to this thread from there.

I'd bet there are more knowledgeable folks in the EMBEDDED/SERVER forums who know about this stuff, and hopefully someone can help you get further.

I wish you the best, and will be following your progress, as I do find it interesting, and stand to learn from your experience.

halturata · 09-24-2007, 06:14 AM

Thanks for the suggestion and for showing such interest in this issue

I'll make a new thread in the suggested forums with link to this one, when I get some more free time later this afternoon.