Hi Karim,

Worked really fine Thank you!

I can use "open" to open the device. However I get a page fault whenever I attempt to write to the device. The device works properly on my ubuntu machine so I can't guess what can be the problem. Would really help if you have any suggestions.

Thank you again
BR,
Nourhan

On Wed, Feb 3, 2016 at 12:00 PM, karim.allah.ahmed@gmail.com <karim.allah.ahmed@gmail.com> wrote:
Hello Nourhan,

On Wed, Feb 3, 2016 at 11:47 AM, Nourhan Mohamed
<nourhan.abdeltawab@gmail.com> wrote:
> Dear all,
>
> I wanted to create a simple character device on L4Linux. I managed to
> cross-compile the module and run it on L4Linux on Versatile Express Realview
> Cortex-A15 ARM machine using the following command:
>
> make -C ~/l4re/obj/l4linux/arm-mp/ M=$PWD
> CROSS_COMPILE=/usr/bin/arm-linux-gnueabi- L4ARCH=arm CONFIG_TCG_TPM=m
> modules V=1
>
> When I try to insert the module using the insmod command I get the following
> printed out from the module:
> chardev: registered correctly with major number 254
> chardev: device class registered correctly
> chardev: device class created correctly
>
> With no failures in initializing the device printed at all. Also lsmod
> displays the device in the module list with status live.
>
> However, the device doesn't appear in the /dev/ directory and hence I can
> not access it using the file operations. Any ideas where is the device
> located or how can it be accessed on L4Linux?

In linux systems, device nodes are not necessarily automatically
generated under /dev/.

Use 'mknod' command-line to create a device node in user space that's
connected to this character device.

Regards.

>
>
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>



--
Karim Allah Ahmed.