Hello,

I have the TimeSys Linux distribution running on the AT91SAM9260-EK. It uses udev, which creates 643 device special files under /dev. Obviously, most of those do not represent actual devices, but it appears to work.

I also have uClibc Buildroot created Linux/BusyBox running on the same board. It does not use udev. The minimal RFS generated by Buildroot includes 109 files under /dev. However, those files are not device special files, they are just regular files that do not operate as an interface to the device drivers. After I discovered that, I used mknod to create /dev/ttyS0 and a couple of other device special files so I could get the board to boot.

I don't like the udev overkill (643 files for mostly non-existent devices, which also slows the boot process), and I don't like the idea of having to individually discover the required mknod command for each actual device if I don't use udev. Does anyone (Atmel?) publish a list of actual device special files with major and minor numbers that are complete and correct for the AT91SAM9260-EK? It seems like every uClibc Buildroot developer would need such a list for their specific target board.

Alternatively, is there something I don't know about uClibc Buildroot such that I could have created a correct set of device special files by configuring something in make menuconfig for the AT91SAM9260-EK?

Thanks.

Jim

Jim,
take a look at MAKEDEV package, it may well enlight you

BTW I wonder why you are using uClinux with a MMU-able cpu

Marco,

Thanks, I will explore MAKEDEV.

I am using uClibc, but that is not the same as uClinux without MMU support, correct?

I use uClibc/Buildroot to build Linux and the RFS for the AT91SAM9260DFC.

If I then use the generated cross-tools to build a simple test program that dereferences a NULL pointer, I get the expected 'Segmentation fault'. That confirms the MMU is operating, right?

Please let me know if I have misunderstood the capabilities of uClibc/Buildroot generated Linux for the AT91SAM9260, and it only supports MMU-less operation. My assumption is that I can use uClibc and BusyBox for small footprint and still benefit from the protection of the MMU on the AT91SAM9260.

Thanks.

Jim

yep

uCLibc s a C library for developing embedded Linux systems. It is much smaller than the GNU C Library, but nearly all applications supported by glibc also work perfectly with uClibc.