Device Tree directory is empty on Linux Linaro Panda 4430.

[Botao]

On TI Panda 4430 board with Linux Linaro image:

http://snapshots.linaro.org/quantal/pre-built/panda/9/panda-quantal_developer_20121206-9.img.gz

Device Tree directory is empty:

root@linaro-developer:/proc/device-tree# pwd
/proc/device-tree
root@linaro-developer:/proc/device-tree# ls -l
total 0
root@linaro-developer:/proc/device-tree#

However, the device tree related log exists in boot log:

## Flattened Device Tree blob at 815f0000
   Booting using the fdt blob at 0x815f0000
   Loading Kernel Image ... OK
OK
   reserving fdt memory region: addr=9d000000 size=3000000
   Using Device Tree in place at 815f0000, end 815f37e1

Starting kernel ...

###################################################################################
This issue is observed on following images:

http://snapshots.linaro.org/quantal/pre-built/panda/9/panda-quantal_developer_20121206-9.img.gz
http://snapshots.linaro.org/quantal/pre-built/panda/12/panda-quantal_developer_20121209-12.img.gz
http://snapshots.linaro.org/quantal/pre-built/panda/20/panda-quantal_developer_20121217-20.img.gz
http://snapshots.linaro.org/quantal/pre-built/panda/41/panda-quantal_developer_20130107-41.img.gz
http://snapshots.linaro.org/quantal/pre-built/panda/44/panda-quantal_developer_20130114-44.img.gz
http://snapshots.linaro.org/quantal/pre-built/panda/51/panda-quantal_developer_20130121-51.img.gz
http://snapshots.linaro.org/quantal/pre-built/panda/58/panda-quantal_developer_20130128-58.img.gz
http://snapshots.linaro.org/quantal/pre-built/panda/68/panda-quantal_developer_20130204-68.img.gz
http://snapshots.linaro.org/quantal/pre-built/panda/71/panda-quantal_developer_20130207-71.img.gz

[Fathi Boudra (fboudra)]

in linux-linaro-llt-omap-3.4: linaro/configs/ubuntu.conf:732:CONFIG_PROC_DEVICETREE=y

The support for device tree in /proc doesn't seems to work on PandaBoard.

[warmcat (andy-warmcat)]

Can you give us the result of strings on your boot.scr? Or if that doesn't exist let us know.

[Fathi Boudra (fboudra)]

On 7 December 2012 11:50, warmcat <email address hidden> wrote:
> Can you give us the result of strings on your boot.scr? Or if that
> doesn't exist let us know.

setenv initrd_high "0xffffffff"
setenv fdt_high "0xffffffff"
setenv bootcmd "fatload mmc 0:1 0x80200000 uImage; fatload mmc 0:1
0x81600000 uInitrd; fatload mmc 0:1 0x815f0000 board.dtb; bootm
0x80200000 0x81600000 0x815f0000"
setenv bootargs "console=tty0 console=ttyO2,115200n8
root=UUID=55ee1017-ab8c-4398-aa20-43cd767582cf rootwait ro earlyprintk
fixrtc nocompcache vram=48M omapfb.vram=0:24M mem=456M@0x80000000
mem=512M@0xA0000000"

[Jassi Brar (jassisinghbrar)]

DT booting is basically hacked to go OK but we don't really use it. See commits ce0d7256a5 and 140bf624dae4. Most features weren't ready yet on 3.4 to boot via DT.

[warmcat (andy-warmcat)]

This won't get fixed on tilt-3.4... what it does at the minute with no proc content accurately reflects the bodge-up that is DT support in that kernel.

In 3.7+ they have moved to proper device tree support, if / when we update to that basis then /proc will be populated as expected.

[Botao (botao-sun)]

Now on TI Panda 4430 with Linux Linaro ubuntu Quantal image:

http://snapshots.linaro.org/quantal/pre-built/panda/249/panda-quantal_developer_20130217-249.img.gz

Device Tree works well.

root@localhost:~# cat /proc/device-tree/model
TI OMAP4 PandaBoard
root@localhost:~# cd /proc/device-tree/

root@localhost:/proc/device-tree# ls -la
total 0
-r--r--r-- 1 root root 4 Feb 17 07:07 #address-cells
-r--r--r-- 1 root root 4 Feb 17 07:07 #size-cells
dr-xr-xr-x 14 root root 0 Feb 17 07:07 .
dr-xr-xr-x 83 root root 0 Jan 1 1970 ..
dr-xr-xr-x 2 root root 0 Feb 17 07:07 aliases
dr-xr-xr-x 2 root root 0 Feb 17 07:07 chosen
-r--r--r-- 1 root root 36 Feb 17 07:07 compatible
dr-xr-xr-x 4 root root 0 Feb 17 07:07 cpus
dr-xr-xr-x 2 root root 0 Feb 17 07:07 interrupt-controller@48241000
-r--r--r-- 1 root root 4 Feb 17 07:07 interrupt-parent
dr-xr-xr-x 2 root root 0 Feb 17 07:07 l2-cache-controller@48242000
dr-xr-xr-x 4 root root 0 Feb 17 07:07 leds
dr-xr-xr-x 2 root root 0 Feb 17 07:07 local-timer@0x48240600
dr-xr-xr-x 4 root root 0 Feb 17 07:07 lpddr2
dr-xr-xr-x 2 root root 0 Feb 17 07:07 memory
-r--r--r-- 1 root root 20 Feb 17 07:07 model
-r--r--r-- 1 root root 1 Feb 17 07:07 name
dr-xr-xr-x 50 root root 0 Feb 17 07:07 ocp
dr-xr-xr-x 5 root root 0 Feb 17 07:07 soc
dr-xr-xr-x 2 root root 0 Feb 17 07:07 sound