AFAIK xtensa linux port is currently in bad shape: it doesn't work in theI wouldn't say it's in bad shape, I just built an vmlinux image from the latest tree (3.6.0-rc1), but it might not be very stable. One of the major issues is not really the kernel but there's actually no way to build a fairly recent version of the toolchain. I have been using a somewhat more recent buildroot version than what is on xtensa-linux.org, but even that version of buildroot is rather old now and needed a few patches.
mainline, it fails to build in the linux-next. The latest working kernels for
xtensa are 2.6.29...31 trees hosted at the git.linux-xtensa.org.
I have a goal to make xtensa arch in the linux mainline usable.Awesome!! Every help is very much appreciated.
Currently I have a number of patches on top of Linus' tree that allow to buildYou might expect that I'm more than curious to see those changes :-)
working allnoconfig, defconfig and allmodconfig kernels for ISS machine with
dc232b and fsf core variants [1]. For the next several weeks I'm planning to
forward-port patches accumulated in linux-xtensa.org git trees and make theThat would be great. Might I also add that we'd need to have a working toolchain and bootable image. For me, buildroot seems to be the quickest route here. That would also require possibly adding patches to the toolchain and uClibc that are currently missing. There's also the bootloader, etc.
resulting kernels rock-solid. I'd like to restore xtensa participation in the
linux-next. Further (currently undetailed) plans are to bring modern Linux
features to the xtensa port, e.g. device trees.
I have a couple of questions regarding the path of xtensa-specific patchesYes, Andrew has been very helpful stepping in and adding those patches. Most if not all of those patches were fixes because of generic kernel changes and not major fixes or changes to the core of the Xtensa port.
upstream:
- which git tree should they be targeted for? Should I set up a tree for
pull requests, or will patches be picked up into some existing tree?
(Looks like Linus' tree is the right target. AFAIK previously xtensa
patches went mostly through akpm tree).
- which mailing lists should they go to?For now, I would really appreciate if you could hold off sending any major patch to the linux-kernel mailing list until we had a chance to look over them unless it's some generic patch (fixing an issue because of an API change to the kernel, etc.)
(I guess that besides linux-xtensa@xxxxxxxxxxxxxxxx list they should go
to linux-kernel@xxxxxxxxxxxxxxx for general review. Anything else?)
Should you wonder what I am:That's so great!! I didn't know there was a QEMU port for Xtensa.
I am a member of St.Petersburg Open Source and Linux Lab [2].
My previous contributions to Linux are related to p54spi wireless driver.
I'm also a developer and maintainer of the target-xtensa QEMU port [3].