Hi Ahmad, On Mon, 2025-02-03 at 13:08 +0100, Ahmad Fatoum wrote: > Hi, > > On 30.01.25 14:55, Ferenc Fejes wrote: > > Hi, > > > > Is it possible to use the serial port for u-boot networking? For example, > > given > > a restricted environment where the FIT image is available with ethernet > > firmware > > and drivers, so it is not possible to boot it with DHCP boot since there is > > no > > networking. Or simply the ethernet NIC has no u-boot driver at all. For such > > cases, I assume ymodem is recommended to download and boot the FIT image. > > > > However, experimenting with different images and debugging, it would be more > > convenient if serial could be used as both data and console channel. Is this > > possible? > > > > A simple example: > > 1. ppp on the host machine, with IP forward, NAT, etc. > > 2. u-boot establish a ppp connection over serial to the host > > 3. u-boot starts a netconsole session to the host > > 4. user can use netconsole and wget to download images > > > > I was thinking of PPP, but that's probably not supported by u-boot. Anything > > similar with RNDIS and USB CDC ACM? > > > > Thanks in advance for any hint! > > If you are willing to implement it, there's RFC 916 (RATP), which > addresses the use case of establishing a reliable communication link over > serial. We use it in barebox to mount remote file systems via serial.
Thank you for the pointer, good to know barebox have such a feature! I assume the license permit what you suggest here, right? > > If you were to implement the same support in U-Boot, you could reuse > the host-side bits without change (and take inspiration from the barebox > implementation of the target-side bits). > > https://github.com/barebox/barebox/blob/master/fs/ratpfs.c > https://www.barebox.org/doc/latest/user/remote-control.html I'll look into this. This looks like an interesting challenge or even better, add SoC bits to barebox (probably that is more work). BTW I have a MT7986 based router and I wanted to install Debian on it. In the process I encountered even though the ETH PHY supported by upstream, and linux- firmware have the required bits as well, none of them included in the installer. So I facing the same issue on Linux side as well :-) On FOSDEM '25 I noticed usb9pfs contribution from you, I really like that idea as well! > > Hope this helps. > > Cheers, > Ahmad > > Best, Ferenc
