Testing IGEP DT support (was: Device Tree on ARM status report - Mar 20)

[Grant Likely]

Hi Mounir,

Took me a while, but here are the instructions for testing DT support on IGEP:

The current nightly u-boot builds should work out-of-the-box with
device tree support.  You can use the prebuilt binaries

>From what I can tell, the kernel build doesn't yet have DT enabled for
any of the platforms.  I need to follow up with John Rigby about this
to make sure I'm looking in the right place.  You'll need to build the
kernel.  Pull the linaro 2.6.38 kernel tree:

git://git.linaro.org/kernel/linux-linaro-2.6.38.git

then:

$ make omap2plus_defconfig
$ vim .config
/* turn on CONFIG_USE_OF and CONFIG_PROC_DEVICETREE */
$ make oldconfig uImage dtbs

Copy the uImage and igep dtb files to the sdcard

Make sure the old boot method still works

Reboot and modify the boot command to load the dtb into ram about 64k
below the initrd image and to use "bootm <kernel-addr> <initrd-addr>
<dtb-addr>" to boot the kernel.

Make sure stuff shows up in /proc/devicetree/.  Also, send me your boot log.

And that's it!

On Mon, Mar 21, 2011 at 3:25 AM, Grant Likely <grant.likely at secretlab.ca> wrote:
> I had great hopes of doing these status reports once a week; but it
> turns out to take more effort to get together that I estimated.
> Here's the status of ARM device tree support as of today.  As always,
> let me know if you have any corrections or additional information.
>
> 1 - Latest news
> ---------------
> - The last vestiges of of_platform_bus_type are gone from Linus' tree
> as of the 2.6.39 merge window.  Everything should be using
> platform_device now.
> - devicetree/arm on git://git.secretlab.ca/git/linux-2.6 has
> everything needed to turn on basic device tree support for any
> platform.
>  - Support has been added for Versatile and Tegra in devicetree/arm
>  - Support for Samsung s5pv310 and Freescale mx5 are in devicetree/test
> - Similarly, u-boot needs to have the CONFIG_OF_LIBFDT and
> CONFIG_SYS_BOOTMAPSZ defined to turn on device tree support.
>  - I've also got patches that eliminate the need for
> CONFIG_SYS_BOOTMAPSZ which I'll post shortly, but they're not quite
> working yet.
>  - I've also got a trivial patch that should enabled CONFIG_OF_LIBFDT
> on a large set of boards, but it has had pretty much zero testing.
> :-)
> - Jason Hui has been making awesome progress on mx5, and some of their
> patches are in devicetree/test.  Hopefully to move over to
> devicetree/arm soon.
> - Shawn Guo has also been making good progress on adding the clock
> bindings to the mx5 support.  There are still questions up in the air
> about the best way to handle clocks though.  While all the clocks
> /can/ be converted to device tree data, there is also value in sharing
> clock initialization data between DT and non-DT board support.  The
> of_platform_device_prepare() work mentioned below will help with that.
>  It will also be easier to work on the clock support when the common
> struct clk patch series from Jeremy gets merged.  Until then there
> ends up being a lot of duplication of code.
> - Lennert has a series of virq patches for ARM patches completed.  He
> is currently working on cleaning them up to get them posted.
> - Patches posted for of_platform_prepare() which makes it easier for
> static platform_device registrations to co-exist with device tree
> data.  Patches are currently in devicetree/test, and will move to
> devicetree/arm shortly.
> - Basic DT support has been merged into Nicolas' Linaro kernel tree.
> - DT is also working on Versatile Express, OMAP, and the new Xilinx
> platform, but I don't have patches for either of those platforms in my
> tree.
> - Rob Herring's work on the early dtb mmu maping is mainlined and
> makes it much nicer to work with dtbs.
>
> Next steps:
> --------------
> At this point I'm putting on my Linaro hat.  Feel free to tune out
> past this point if you're not interested how DT support will
> materialize in the next release.
>
> There are a number of very specific tasks that need to be completed
> for the 11.05 release.  The goal is to have basic device tree support
> turned on and working on all of the platforms supported in the
> release.  There isn't a lot of time to get this pulled together, but
> all the infrastructure is in places, so most of the work is turning on
> the configuration options and testing the platforms.
>
> For each board, I need an engineer to do the following:
>
> 1) Enable CONFIG_OF_LIBFDT and CONFIG_SYS_BOOTMAPSZ against the Linaro
> u-boot tree.
> 2) Enable CONFIG_OF and CONFIG_PROC_DEVICETREE in the kernel
> 3) Add something like the following to the *existing* machine
> definition.  For initial basic support, you don't need to create a
> separate <soc>-dt.c board support file yet.
>
> +static const char *omap4_panda_dt_match[] __initdata = {
> +       "ti,omap4-panda",
> +       NULL
> +};
> +
>  MACHINE_START(OMAP4_PANDA, "OMAP4 Panda board")
> [...]
> +       .dt_compat      = omap4_panda_dt_match,
>  MACHINE_END
>
>    The string in the match table should be in the form "<vendor>,<board-name>"
>
> 4) Add a template .dts file for the board in
> arch/arm/boot/dts/<board>.dts.  The following should be sufficient:
>
> /dts-v1/;
>
> / {
>        model = "TI OMAP4 PandaBoard";
>        compatible = "ti,omap4-panda";
>        #address-cells = <1>;
>        #size-cells = <1>;
>
>        aliases {
>        };
>
>        memory {
>                device_type = "memory";
>                reg = <0x80000000 0x08000000>;
>        };
>
>        chosen {
>        };
> };
> 5) test it  :-)
> 6) send patches to me for inclusion in the Linaro U-Boot and Kernel
> trees.  I'll collect them to start and ask John and Nicolas to pull
> them into their trees when they're ready.
>
> This is enough for very basic device tree support and I expect it will
> only take a day or so of effort to get completed.  It won't be
> particularly useful, but it ensures that the infrastructure is enabled
> and working.
>
> Bonus points if you're also able to provide patches that add
> of_platform_device_probe() and of_platform_bus_populate() calls to the
> board support so that device nodes get attached to the devices and can
> be used for attaching things like gpios, spi devices, and i2c devices.
>  This is a nice to have for 11.05, but it isn't a requirement to have
> it working on all boards.
>
> Here is the list of hwpacks that should be supported to the best of my
> knowledge.  Please reply with the hwpacks you can take responsibility
> for:
>
> efikamx
> igep
> imx51
> omap3-x11-base
> omap3
> overo
> panda
> s5pv310
> vexpress
>
> There are also some specific cross-platform tasks that need some love.
>  Let me know if you can take responsibility for any of these items.
> - Eliminate CONFIG_SYS_BOOTMAPSZ dependency from U-Boot.  I've got a
> patch series that does this, but it is untested.  I'll post the series
> tomorrow.
> - Add packaging of .dtb files into linux-image-linaro-* packages.
> Loic and I discussed putting them under /lib/dtb/`uname -r`/, but
> thinking about it more, it might make more sense to share the modules
> directory and use /lib/modules/`uname -r`/dtbs.  The dtc tool needed
> to build the .dtbs is included with the kernel tree.
> - Add relevant dtb files to boot partition in linaro-image tools
> - Add boot script which passes dtb as 3rd argument to 'bootm'
>
> For purposes of tracking, I'll register bugs for the above items in
> the Linaro bug tracker tomorrow.
>
> Cheers,
> g.
>
> --
> Grant Likely, B.Sc., P.Eng.
> Secret Lab Technologies Ltd.
>



-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.