Re: [microblaze-uclinux] howto add a new kernel driver in the uclinux_distfiletree?

[John Williams <jwilliams@xxxxxxxxxxxxxx>]

Hi Falk,

Brettschneider Falk wrote:

> I wrote a new uclinux kernel driver (irq handler called 'vsint') and
> inserted it in the kernel file-tree in a way that it is compiled when I
> compile the uclinux kernel. But on booting that kernel the new driver is not
> loaded. What is missing? I digged through the docs and archives but haven't
> found a hint.
> 
> Here is what I've done:
> 1.) added directory uclinux_dist/linux-2.4.x/drivers/vsint with the source
> file vsinthandler.c and the Makefile:

It is fairly unconventional to add a new subdir directly under drivers - 
normally they would be added under one of drivers/ subdirectories 
(ne3t/char/misc/block etc).  For example, you can see under drivers/misc 
where I added the FSLFIFO driver.

Anyway, examine the command executed by make in the final stage of 
linking the kernel.  If you do "make linux", it will be the last few 
lines of output.

Make sure that your new subdir is included in that final link.

  > 2.) added stuff in uclinux_dist/linux-2.4.x/drivers/Makefile:
> 	...
> 	mod-subdirs :=	... vsint
> 	...
> 	subdir-$(CONFIG_VSINT)+= vsint
> 	...

This seems the right approach.  You should double check your 
linux-2.4.x/.config file, that your CONFIG_VSINT variable is set.

> 3.) added an entry in uclinux_dist/linux-2.4.x/arch/microblaze/config.in:
> 	...
> 	#added by Baumer Optronic mha/fbr/rae
> 	source drivers/vsint/Config.in
> 	...

Maybe check for a typo in drivers/vsint/Config.in?

> 4.) went again through the 'make xconfig'-procedure and activated the new
> driver in the graphical menu
> 5.) called 'make dep all' and have seen how the new driver successfully
> compiles,

Again, you must make sure it succesfully links into the kernel image. 
If you have it set as a loadable module, then of course you must use 
lsmod at runtime to load the module.

> 6.) but the driver is not loaded on bootup :-(although it works well in my
> PC linux version).

Are you statically linking the module into your PC kernel, or building 
it as a module?

> What else is to do for activating the driver in that modified kernel?

It seems like you have the major parts in place, I would now be looking 
for some subtle error, like a typo in a Makefile or config.in file.

Regards,

John


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