Devicetree state of U-Boot vs kernel

[Bill Mills]

All,

On the Devicetree evolution call Wednesday I promised to finish my 
comparison of u-boot DT vs kernel DT.
The script is not perfect but the results are still interesting.

For each dts and dtsi file in the tip of the u-boot tree, it tries to 
correlate it to the kernel tip.
It compares git SHA1 signatures or falls back to filenames.
The results were surprising to me but perhaps they should not have been.

I have checked in the script[1] and the full results here [2]

The full file lists (with some diff stats) are in the root dir.
Example [3]

I also looked at the line count of the u-boot override files.
Even though we don't expect these to correlate, we do expect reasonable 
usage to result in small files.  Big files are an indication of possible 
abuse of the system.  (I don't think the idea was to have wholesale new 
versions of the DTS as an override.)

I plan to redo the script in python.  It will be much easier to be more 
precise and to look deeper.  (For example figure out how old the u-boot 
version is in number of change sets and number of days.  Or if no 
content sync now were they ever synced?)

Here is the scripts output: (from summary.txt)

Devicetree sync status for u-boot v2021.01-rc5-7-gb8c725e736
Compared to kernel v5.11-rc2-156-g71c061d24438
14% (255) are completely synced
      253 arm
        2 riscv
        0 mips
        0 powerpc
        0 x86
        0 68k
        0 microblaze
        0 sh
        0 arc
23% (416) content has appeared in the kernel but is not up to date
      411 arm
        0 riscv
        1 mips
        0 powerpc
        1 x86
        0 68k
        0 microblaze
        0 sh
        1 arc
33% (584) filename appears in kernel but content never has
      467 arm
        1 riscv
       12 mips
       91 powerpc
        0 x86
        0 68k
        0 microblaze
        0 sh
        8 arc
28% (510) neither filename nor content appears in kernel
      305 arm
        4 riscv
       48 mips
       35 powerpc
       44 x86
        0 68k
        1 microblaze
        1 sh
        6 arc
n/a (510) U-Boot specific, no correlation expected
        7 sandbox
      358 override
      211 test
histogram of override size (in raw lines)
    10  61
    20  53
    30  38
    40  33
    50  23
    60  14
    70  12
    80   7
    90   5
   100   4
   110   4
   120   5
   130   6
   140   4
   150   0
   160   2
   170   0
   180   0
   190   4
   200   0
   210   2
   220   2
   230   1
   240   2
   250   1
   260   1
   270   1
   280   0
   290   0
   300   0
   310   0
   320   1


[1] 
https://github.com/wmamills/devicetree-source/blob/master/scripts/correlate-dts
[2] https://github.com/wmamills/devicetree-source
[3] 
https://github.com/wmamills/devicetree-source/blob/master/dts-somewhere.txt

-- 
Bill Mills
Principal Technical Consultant, Linaro
+1-240-643-0836
TZ: US Eastern
Work Schedule:  Tues/Wed/Thur