Date
1 - 13 of 13
Invitation and RFC: Linux Plumbers Device Tree track proposed
Rowand, Frank <Frank.Rowand@...>
In recent years there have been proposed tools to aid in the creation of valid
device trees and in debugging device tree issues. An example of this is the various approaches proposed (with source code provided) to validate device tree source against valid bindings. As of today, device tree related tools, techniques, and debugging infrastructure have not progressed very far. I have submitted a device tree related proposal for the Linux Plumbers 2015 conference to spur action and innovation in such tools, techniques, and debugging infrastructure. The current title of the track is "Device Tree Tools, Validation, and Troubleshooting". The proposal is located at http://wiki.linuxplumbersconf.org/2015:device_tree_tools_validation_and_trouble_shooting I am looking for several things at the moment: 1) Suggestions of additional topics to be discussed. 2) Emails or other messages expressing an interest in attending the device tree track. 3) Commitments to attend the device tree track (the conference committee is looking at attendee interest and commitments as part of the process of accepting the device tree track). 4) Identifying additional people who should attend the device tree track. The desired outcome of the device tree track is to encourage the future development of tools, process, etc to make device tree related development, test, review and system administration more efficient, faster, easier, more robust, and to improve troubleshooting and debugging facilities. Some examples of areas of interest could include: - make it easier to create correct device tree source files - support for debugging incorrect device tree source files - create a kernel that correctly boots one or more specific device trees (eg a kernel configured to include the proper drivers and subsystems) - create drivers that properly work for a device tree binding definition - create drivers that support detecting errors in the related node(s) in a device tree The wiki page lists additional areas of interest. Thanks, Frank Rowand Sony Mobile Communications
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Rob Landley
On Sat, Apr 11, 2015 at 2:20 PM, Rowand, Frank
<Frank.Rowand@...> wrote: In recent years there have been proposed tools to aid in the creation of validIs there a device tree porting HOWTO anywhere? If I have a board that's using explicit C initialization, and I want to convert it over to device tree, step by step what do I do? If I'm writing a new board support, what device tree bits do I need to get a shell prompt on a serial port running out of initramfs? (Physical memory, interrupt controller, timer to drive the scheduler, serial chip...) There's a bunch of device tree reference material out there, but no tutorial material at all, that I can find... Rob
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Geert Uytterhoeven
Hi Rob,
On Sun, Apr 12, 2015 at 2:05 AM, Rob Landley <rob@...> wrote: Is there a device tree porting HOWTO anywhere? If I have a boardhttp://www.devicetree.org/Device_Tree_Usage Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@... In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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Rob Herring <robherring2@...>
On Sat, Apr 11, 2015 at 2:20 PM, Rowand, Frank
<Frank.Rowand@...> wrote: In recent years there have been proposed tools to aid in the creation of validA few things on my list: - Supported and not supported overlay usecases - Tools for overlays - I think overlays has created new challenges in validation and a need for new tools. How to test an overlay applies? Generating a dtb from dts + overlay dts. Generating an overlay from a diff of old and new dts (overlay as a way to update old dtbs) - Shrinking the binding review fire hose. How to improve binding documentation structure and review. - Standardizing Android dtb handling. Appended DTB for arm64? Not liked by upstream, but already in use. 2) Emails or other messages expressing an interest in attending theI plan to attend. I'm probably attending some of the Android mini conf too, so I'll have to split my time. 4) Identifying additional people who should attend the device tree track.Arnd Bergmann Matt Porter Jon Loeliger Gaurav Minocha Rob The desired outcome of the device tree track is to encourage the future
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Mark Rutland <mark.rutland@...>
On Tue, Apr 14, 2015 at 04:36:15PM +0100, Rob Herring wrote:
On Sat, Apr 11, 2015 at 2:20 PM, Rowand, FrankI guess Kernel-driven overlay application (it's been called "quirks" elsewhere) would fall under this? It's rather scary, and would need fairly strict rules to be feasible and remain maintainable, which is going to limit where it can be used. I think the core guys for that are on the list already? - Standardizing Android dtb handling. Appended DTB for arm64? NotIf people are going to package a kernel and DTB together, it would be nice if they could at least be easily decomposed (using something like FIT). So +1 for that discussion. I'm interested.2) Emails or other messages expressing an interest in attending the If the DT track goes ahead, I'll be there.3) Commitments to attend the device tree track (the conference committee Mark.
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Arnd Bergmann <arnd@...>
On Tuesday 14 April 2015 10:36:15 Rob Herring wrote:
Sorry, I won't be there. I should have replied earlier, but I'll be on4) Identifying additional people who should attend the device tree track.Arnd Bergmann parental leave at the time. Arnd
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Matt Porter <mporter@...>
On Tue, Apr 14, 2015 at 10:36:15AM -0500, Rob Herring wrote:
On Sat, Apr 11, 2015 at 2:20 PM, Rowand, Frank- Clean up of existing hardware-specific bindings to conform to the generic bindings, working dts files in the kernel tree, and bring consistency to the documentation style/syntax. I also plan to attend. I have an interest in most of the topics already2) Emails or other messages expressing an interest in attending theI plan to attend. I'm probably attending some of the Android mini conf mentioned as well as the topic I added above. -Matt
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Rob Landley
On 04/11/2015 02:20 PM, Rowand, Frank wrote:
In recent years there have been proposed tools to aid in the creation of validWant I want to do is: 1) Download an archive of device tree files describing a bunch of boards. (Both dts and corresponding dtb files, with maybe a .txt telling me about the board and the -append line qemu needs to give it any board-specific kernel command line stuff like "console=myserialport".) 2) Feed one of the dtb files to qemu to instantiate a bunch of devices. 3) Feed the same file to a generic-ish linux kernel to bind to those devices. (Or have qemu do this for me.) Every year or so I sit down to figure out how to do this, spent fifteen minutes head scratching, and wander away again. The archive in 1) should have subdirectories for architectures, with the same name as the corresponding kernel arch directory. It would be nice if there was some sort of dts_defconfig that built a vmlinux that statically linked in all the drivers with a device tree binding. It would be _really_ nice if qemu's vmlinux loader actually worked on all the hardware targets. In theory, this should be easy. In practice, I've never made it work. Rob
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Geert Uytterhoeven
Hi Rob,
On Fri, May 1, 2015 at 11:22 PM, Rob Landley <rob@...> wrote: The archive in 1) should have subdirectories for architectures, with the"Generating .config from DTS" https://groups.google.com/forum/#!topic/linux.kernel/xYrKolsgr0Y In the mean time, partial mathing (for i2c/spi devices) has been implemented. https://github.com/geertu/linux-scripts/blob/master/linux-config-from-dt It needs more work to generate a full .config, though. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@... In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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Rob Herring <robherring2@...>
On Fri, May 1, 2015 at 4:22 PM, Rob Landley <rob@...> wrote:
On 04/11/2015 02:20 PM, Rowand, Frank wrote:The dts half is here[1]. It is a kernel repository automaticallyIn recent years there have been proposed tools to aid in the creation of validWant I want to do is: stripped of everything but dts files. 2) Feed one of the dtb files to qemu to instantiate a bunch of devices.I'd like this too. The QEMU maintainers don't really agree. I think the ARM virt platform is the wrong way around with QEMU generating the DT. There was a patch series to allow sysbus devices to be created on the command line like you can with PCI. This would have allowed a front end script to generate a QEMU command line from a DT. I'm not sure if it ever got in. It would lower the bar to adding new platforms to just writing models for blocks perhaps. I'm not sure there's enough interest. The number of ARM platforms supported in QEMU is much less than the kernel. Rob [1] https://git.kernel.org/cgit/linux/kernel/git/devicetree/devicetree-rebasing.git/
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Geert Uytterhoeven
Hi Rob
On Tue, May 5, 2015 at 1:20 AM, Rob Herring <robherring2@...> wrote: On Fri, May 1, 2015 at 4:22 PM, Rob Landley <rob@...> wrote:Great!On 04/11/2015 02:20 PM, Rowand, Frank wrote:The dts half is here[1]. It is a kernel repository automaticallyIn recent years there have been proposed tools to aid in the creation of validWant I want to do is: While "git log" has the "--nomerges" option, cgit hasn't, making it hard to see the actual changes through the forest of merges. Any chance merge commits not causing any changes can be stripped out, too? Thanks! Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@... In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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Rob Herring <robherring2@...>
+Ian
On Tue, May 5, 2015 at 2:34 AM, Geert Uytterhoeven <geert@...> wrote: Hi RobThat's a question for Ian. Rob
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David Gibson <david@...>
On Mon, May 04, 2015 at 06:20:35PM -0500, Rob Herring wrote:
On Fri, May 1, 2015 at 4:22 PM, Rob Landley <rob@...> wrote:I suggested something like this several years ago to Anthony LiguoriOn 04/11/2015 02:20 PM, Rowand, Frank wrote:The dts half is here[1]. It is a kernel repository automaticallyIn recent years there have been proposed tools to aid in the creation of validWant I want to do is: who didn't much like it. However qemu has changed a fair bit since then, so it might be worth revisiting. It's a big job though - lots of integration work with qemu's configuration core. In particular allowing this without breaking migrations or the various qapis is not straightforward. It would lower the bar to adding new platforms to just writing modelsI havea presentation proposal for KVM Forum covering some ideas which could be at least first steps towards doing this. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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