On Tue, Jan 12, 2021 at 1:13 AM Rob Herring [off-list ref] wrote:

+David Gibson

On Mon, Jan 11, 2021 at 9:40 AM Masahiro Yamada [off-list ref] wrote:

quoted

On Mon, Jan 11, 2021 at 8:17 PM Viresh Kumar [off-list ref] wrote:

quoted

On 07-01-21, 14:28, Masahiro Yamada wrote:

quoted

Viresh's patch is not enough.

We will need to change .gitignore
and scripts/Makefile.dtbinst as well.

In my understanding, the build rule is completely the same
between .dtb and .dtbo
As Rob mentioned, I am not sure if we really need/want
a separate extension.

A counter approach is to use an extension like '.ovl.dtb'
It clarifies it is an overlay fragment without changing
anything in our build system or the upstream DTC project.

By the time you gave feedback, I have already sent the dtbo change for
DTC to the device-tree-compiler list (based on Rob's suggestion).

And it got merged today by David:

https://github.com/dgibson/dtc/commit/163f0469bf2ed8b2fe5aa15bc796b93c70243ddc

Can we please finalize what we need to do with naming here and be done
with it, so I can rework my patches and get going ?

Thanks.

--
viresh

It is unfortunate to see such a patch merged
before getting agreement about how it should work
as a whole.

Given the feedback that dtbo is already a standard, I'd suggest we
just stick with dts->dtbo.

OK.
dtbo seems a stanrdard already...

quoted

quoted

+# enable creation of __symbols__ node
+ifneq ($(dtbo-y),)
+DTC_FLAGS += -@
+endif

I am not convinced with this code.

A single user of the dtbo-y syntax gives -@ to all
device trees in the same directory.

This is not a solution since Rob already stated -@ should be
given per board (or per platform, at least).

Agreed.

quoted

I still do not understand why adding the new syntax dtbo-y
is helpful.

I think we should stick with 'dtb-y' here.

quoted

Have we already decided to use separate ".dtb" and ".dtbo" for blobs?

Will we use ".dts" for all source files?
Or, will we use ".dtso" for overlay source files?

How should the build system determine the targets
that should have -@ option?

The way it does already. Either:

DTC_FLAGS += -@

in a directory of dts files. Or on a per file basis like:

DTC_FLAGS_foo_base += -@

Ah yes.  I like this.




We do not need the dtbo-y syntax.


We can simply use dtb-y for
base boards and overlay fragments:



dtb-$(CONFIG_ARCH_FOO) += \
     foo-base.dtb \
     foo-overlay1.dtbo \
     foo-overlay2.dtbo

DTB_FLAGS_foo-base += -@

quoted

For consistency, will we need a patch like follows?

diff --git a/dtc.c b/dtc.c
index bdb3f59..474401e 100644
--- a/dtc.c
+++ b/dtc.c

@@ -120,6 +120,8 @@ static const char *guess_type_by_name(const char

*fname, const char *fallback)
                return fallback;
        if (!strcasecmp(s, ".dts"))
                return "dts";
+       if (!strcasecmp(s, ".dtso"))
+               return "dts";
        if (!strcasecmp(s, ".yaml"))
                return "yaml";
        if (!strcasecmp(s, ".dtb"))

@@ -349,6 +351,8 @@ int main(int argc, char *argv[])

        if (streq(outform, "dts")) {
                dt_to_source(outf, dti);
+       else if (streq(outform, "dtso")) {
+               dt_to_source(outf, dti);
 #ifndef NO_YAML
        } else if (streq(outform, "yaml")) {
                if (!streq(inform, "dts"))

Overall solution looks unclear to me.


Again, it is unfortunate that we did not take enough time
(in spite of the RFC prefix) before proceeding.

I should have added David here from the start. Honestly, I expected
some discussion there.

Rob

-- 
Best Regards
Masahiro Yamada