Developing with RTEMS on the host

[Russell Haley]

On Fri, Jun 2, 2017 at 4:37 PM, Russell Haley <russ.haley at gmail.com> wrote:
> On Fri, Jun 2, 2017 at 3:12 PM, Denis Obrezkov <denisobrezkov at gmail.com> wrote:
>> 2017-06-03 0:55 GMT+03:00 Steven Grunza <steven.grunza at gmail.com>:
>>>
>>> Why avoid frequent ROM writing?  Most of the systems on which I have
>>> worked that would be suitable for RTEMS saved the code in Flash memory -
>>> most of them used on-board Flash.  Can you describe the hardware a little?
>>> CPU, memory, etc?
>>>
>>> To run from NFS it seems like there would need to be some code on-board to
>>> get a bootloader started so that networking was available to access the NFS
>>> shared file and download it to RAM, then jump to it.
>
> In FreeBSD I have used u-boot to achieve this for an ARM board (imx53
> and imx6). I used TFTP to load the kernel and execute it at a specific
> memory address, and then NFS to mount the root file system. If memory
> serves I created a partition table with 1MB at the front and then a
> fat32 partition. I dd u-boot to the SD Card (leaving a couple of
> sectors at the front for the partition table) and then wrote the
> env.txt file to the MSDOS partition. Possibly you could use TFTP to
> grab the executables and run them. If u-boot can't load RTEMS, perhaps
> you could write a small second/third stage boot loader? In FreeBSD
> they have something called ubldr that works as a shim between uboot
> and the kernel that understands UFS and ZFS.
>
> However, Barebox would be a FAR better choice for this. Looking at the
> documentation it supports NFS out of the gate. I have used it in
> simple configurations and it is superior to u-boot because it uses
> shell like scripts and has a single point for all board support
> packages (as compared to u-boot that has been forked all over the
> place). It also supports multiple architectures and is super duper
> easy to build if you're running GNU/Linux (has some Linux dependencies
> in the build system).
>
> http://www.barebox.org/
>
Oh, also the primary developer is a great guy and always looking at
ways to improve the software. He offered to support me porting it over
to FreeBSD.

Russ