On Tue, Jan 21, 2020 at 09:59:44AM -0600, Rob Herring wrote: > On Sun, Jan 19, 2020 at 12:41 AM David Gibson > wrote: > > > > On Fri, Jan 17, 2020 at 08:43:23AM -0600, Rob Herring wrote: > > > On Fri, Jan 17, 2020 at 6:26 AM David Gibson > > > wrote: > > > > > > > > On Thu, Jan 16, 2020 at 09:58:23AM +0100, Alexandre Torgue wrote: > > > > > Hi David > > > > > > > > > > On 1/16/20 1:57 AM, David Gibson wrote: > > > > > > On Mon, Jan 13, 2020 at 07:16:23PM +0100, Alexandre Torgue wrote: > > > > > > > This commit adds the possibility to add build information for a DTB. > > > > > > > Build information can be: build date, DTS version, "who built the DTB" > > > > > > > (same kind of information that we get in Linux with the Linux banner). > > > > > > > > > > > > > > To do this, an extra option "-B" using an information file as argument > > > > > > > has been added. If this option is used, input device tree is appended with > > > > > > > a new string property "Build-info". This property is built with information > > > > > > > found in information file given as argument. This file has to be generated > > > > > > > by user and shouldn't exceed 256 bytes. > > > > > > > > > > > > > > Signed-off-by: Alexandre Torgue > > > > > > > > > > > > At the very least, this patch of the series will need to be sent to > > > > > > upstream dtc first. > > > > > > > > > > Ok sorry. I thought that sending all the series would give more > > > > > information. > > > > > > > > That's fair enough, but in order to merge, you'll need to post against > > > > upstream dtc. > > > > > > > > > > I'm also not terribly clear on what you're trying to accomplish here, > > > > > > and why it's useful. > > > > > > > > > > Let's take Kernel boot at example (but could be extend to other DTB "users" > > > > > like U-Boot). When Linux kernel booting we get a log that gives useful > > > > > information about kernel image: source version, build date, people who built > > > > > the kernel image, compiler version. This information is useful for debug and > > > > > support. The aim is to get same kind of information but for the DTB. > > > > > > > > > > > Since you're doing this specifically for use with dtbs built in the > > > > > > kernel build, could you just use a: > > > > > > Build-info = /incbin/ "build-info.txt"; > > > > > > in each of the in-kernel .dts files? > > > > > > > > > > My first idea was to not modify all existing .dts files. Adding an extra > > > > > option in dtc is (for me) the softer way to do it. I mean, compile > > > > > information should come through compiler without modify .dts files outside > > > > > from dtc. In this way it will be easy to everybody using dtc (inside our > > > > > outside Linux tree) to add dtb build info (even if they don't how to write a > > > > > dts file). > > > > > > > > But you're not really having this information coming from the > > > > compiler. Instead you're adding a compiler option that just force > > > > includes another file into the generated tree, and it's up to your > > > > build scripts to put something useful into that file. > > > > > > > > I don't really see that as preferable to modifying the .dts files. > > > > > > > > I also dislike the fact that the option as proposed is much more > > > > general than the name suggests, but also very similar too, but much > > > > more specific than the existing /incbin/ option. > > > > > > > > What might be better would be to have a dtc option which force appends > > > > an extra .dts to the mail .dts compiled. You can then put an overlay > > > > template in that file, something like: > > > > > > > > &{/} { > > > > linux,build-info = /incbin/ "build-info.txt; > > > > } > > > > > > I like this suggestion either as an include another dts file or an > > > overlay. > > > > Sorry, to be clear what I'm talking about here is just including > > another dts file, and using the compile-type overlay syntax. This is > > not the same as .dtbo style runtime overlays (though the final result > > is about the same in this case). > > Ah, okay. That's probably easier to implement. > > > > The latter could be useful as a way to maintain current dtb > > > files while splitting the source files into base and overlay dts > > > files. > > > > > > But no, let's not prepend this with 'linux'. It's not a property > > > specific for Linux to consume. > > > > It's not really about who consumes it. It's about defining a > > namespace for the new property to exist in, since it's not part of a > > relevant standard (if we wanted to make it such, we should pin down > > what goes in there with much more precision). > > I can't think of any cases of the 'linux' prefix not being about who > consumes it. And we often end up dropping 'linux' because it turns out > to not be Linux specific. I don't care to see u-boot,build-info, > freebsd,build-info, etc. when a given dtb can only have 1 of those. But all other vendor prefixes are about who generated or specified the information, not who consumes it, e.g. "ibm,XXX", "fsl,YYY", etc. > My intent is this property name is added to the DT spec, but I don't > agree we should define what's in it beyond a string. It is information > that is useful for humans identifying what the dtb was built from. > > Rob > -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson