Re: [RFC PATCH 0/3] Add device tree build information

Frank Rowand
2020-01-20T16:14:25Z

On 1/20/20 4:56 AM, Alexandre Torgue wrote:
> Hi Franck
>
> On 1/17/20 8:13 PM, Frank Rowand wrote:
>>
>> On 1/16/20 2:19 AM, Alexandre Torgue wrote:
>>> Hi Franck,
>>>
>>> On 1/16/20 3:28 AM, Frank Rowand wrote:
>>>> On 1/13/20 12:16 PM, Alexandre Torgue wrote:
>>>>> Hi,
>>>>>
>>>>> The goal of this series is to add device tree build information in dtb.
>>>>> This information can be dtb build date, where devicetree files come from,
>>>>> who built the dtb ... Actually, same kind of information that you can find
>>>>> in the Linux banner which is printout during kernel boot. Having the same
>>>>> kind of information for device tree is useful for debugging and maintenance.
>>>>>
>>>>> To achieve that a new option "-B" (using an argument) is added to dtc.
>>>>> The argument is a file containing a string with build information
>>>>> (e.g., From Linux 5.5.0-rc1 by alex the Mon Jan 13 18:25:38 CET 2020).
>>>>> DTC use it to append dts file with a new string property "Build-info".
>>>>>
>>>>> of/fdt.c is modified to printout "Build-info" property during Kernel boot and
>>>>> scripts/Makefile.lib is modified to use dtc -B option during kernel make (this
>>>>> last part could be improved for sure).
>>>>
>>>> Please read through the thread at:
>>>>
>>>>     https://lore.kernel.org/linux-arm-kernel/550A42AC.8060104@gmail.com/
>>>>
>>>> which was my attempt to do something similar.
>>>
>>> Yes the idea is the same: get build DTB information like build date,
>>> "who built the DTB" ... The difference seems to be the way to do it.
>>> In my case, I don't want to modify existing dts source files., but I
>>> "just" append them by creating a new property with a string
>>> containing this build information.>
>>> Why your proposition has not been accepted ?
>>
>> Since you are asking this question, I am presuming that you did not
>> read the replies in the thread I referenced.  Please read through
>> the entire thread.  Most of the review comments were objecting to
>> the concept of my proposal.
>
> Sorry I have been lazy :$. This series is a tiny one compare to
> yours, and adds less dtb information (only git used, who built dtb

> and the date). There are no "dtb versions", and "absolute/relative"
> path which created concerns. One remaining concern is "reproducible

Here is an example of the info from one of my builds:

From Linux 5.5.0-rc2-dirty by frowand the Mon Jan 20 09:50:58 CST 2020.

The information 'Linux 5.5.0-rc2-dirty' is precisely what was most objected
to in my proposal.

-Frank

> build" but making dtb info optional could respond to it. I continue
> to think that it's useful to get those information (even if it's only
> a string) But before continuing (and find a better technical way to
> do it), I need to know if there are no other obstacles.
>
> Regards
> Alex
>
>
>>
>> -Frank
>>
>>>
>>> Regards
>>> Alex
>>>
>>>>
>>>> -Frank
>>>>
>>>>>
>>>>> Regards
>>>>> Alex
>>>>>
>>>>> Alexandre Torgue (3):
>>>>>     dtc: Add dtb build information option
>>>>>     of: fdt: print dtb build information
>>>>>     scripts: Use -B dtc option to generate dtb build information.
>>>>>
>>>>>    drivers/of/fdt.c           |  9 +++++++
>>>>>    scripts/Makefile.lib       | 11 +++++---
>>>>>    scripts/dtc/dtc.c          | 55 +++++++++++++++++++++++++++++++++-----
>>>>>    scripts/gen_dtb_build_info | 11 ++++++++
>>>>>    4 files changed, 76 insertions(+), 10 deletions(-)
>>>>>    create mode 100755 scripts/gen_dtb_build_info
>>>>>
>>>>
>>>
>>
>