02:45 <mescobar> somlo yeah I would like the compiled app to be loaded over serial

02:46 <mescobar> I'm assuming that including object file within the file system is the only way to go

02:46 <mescobar> I don't think gcc is included with the linux kernel, right?

05:44 <keesj> wow.. it won't take long before the rootfs will be mounted over NFS

07:12 <daveshah> I did actually have an NFS rootfs working with litex linux

07:12 <daveshah> Was very useful for userspace debugging, although liteeth is pretty slow

07:13 <daveshah> In any case the place to put new userspace programs is in buildroot, which is where rootfs.cpio comes from

08:05 <keesj> I done such setup many times but every time it is a bit of work (again) also (when having a u-boot bootloader) Downloading linux/rootfs over tftp can also be nice

10:53 <somlo> mescobar: ok, so there are a number of steps on the path between CSRs and linux userspace (i.e. stuff running from a linux rootfs)

10:54 <somlo> first, you probably want to build a full litex SoC including the bios (bare-metal software included in the bitstream that runs as soon as the soft CPU "wakes up")

10:54 <somlo> a description of the CSRs MMIO addresses is typically generated under "build/<boardname>/software/include/generated/csr.h"

10:55 <somlo> and used to compile the bios binary, which is then added as "rom" to the gateware/bitstream

10:56 <somlo> mescobar: this stuff runs when you program the bitstream to your board, and it's smart enough to load a bunch of other things via either tftp or from an sdcard

10:56 <somlo> that's where you want things like a DTB blob, linux kernel, initrd, etc.

10:57 <somlo> you use the DT blob to tell e.g. linux what CSRs live at what addresses (more or less mirroring the generated csr.h)

10:58 <somlo> and it's linux (or whatever kernel) that's expected to have drivers for the hardware, and tickle the CSRs, not so much userspace code

10:59 <somlo> check out https://github.com/litex-hub/linux/tree/litex-rocket-rebase for a few examples of linux device drivers interacting with LiteX CSRs

10:59 <tpb> Title: GitHub - litex-hub/linux at litex-rocket-rebase (at github.com)