Sorry for the delay, been away for a few days. On Mon, Feb 19, 2018 at 12:24 AM, Frank Rowand <frowand.list@xxxxxxxxx> wrote: > > On 02/18/18 17:46, Rob Herring wrote: > > On Sun, Feb 18, 2018 at 6:29 PM, <frowand.list@xxxxxxxxx> wrote: > >> From: Frank Rowand <frank.rowand@xxxxxxxx> > >> > >> kbuild test robot reported a new warning for a recent patch: > >>>> drivers/of/overlay.c:832:2: error: implicit declaration of function 'of_fdt_unflatten_tree' [-Werror=implicit-function-declaration] > >> of_fdt_unflatten_tree(new_fdt, NULL, &overlay_root); > >> > >> The cause is that the prototype for of_fdt_unflatten_tree() in > >> include/linux/of_fdt.c is guarded by OF_EARLY_FLATTREE. Umm, this is not true. of_fdt_unflatten_tree is outside the ifdef for OF_EARLY_FLATTREE. > >> > >> This was a pre-existing problem for any overlay related caller of > >> of_fdt_unflatten_device_tree(), who was then going to pass the > >> unflattened tree to of_overlay_apply(). After the patch that triggered > >> this warning, all other overlay callers of of_fdt_unflatten_device_tree() > >> no longer exist, so adding the select to OF_OVERLAY is a sufficient fix. > >> > >> To reproduce the warning: > >> Use the .config attached to https://lkml.org/lkml/2018/2/17/268 > >> make ARCH=i386 olddefconfig > >> make ARCH=i386 CC=gcc-7 drivers/of/overlay.o > >> > >> Signed-off-by: Frank Rowand <frank.rowand@xxxxxxxx> > >> --- > >> drivers/of/Kconfig | 1 + > >> 1 file changed, 1 insertion(+) > >> > >> diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig > >> index 783e0870bd22..00a6abfaaec7 100644 > >> --- a/drivers/of/Kconfig > >> +++ b/drivers/of/Kconfig > >> @@ -92,6 +92,7 @@ config OF_RESOLVE > >> config OF_OVERLAY > >> bool "Device Tree overlays" > >> select OF_DYNAMIC > >> + select OF_EARLY_FLATTREE This should really have been OF_FLATTREE... > > If we do this, we might as well kill OF_EARLY_FLATTREE. What platform > > really boots from not FDT, but uses DT without overlays? > > Making sure I'm understanding... So you want to remove OF_EARLY_FLATTREE > and convert the current users of it to OF_FLATTREE? Right. OF_EARLY_FLATTREE just controls everything that's in __init section anyway. So the question is it worth a kconfig option to control code that's in the __init section and will get discarded anyway? > I don't see any way to directly configure OF_FLATTREE and I don't see any > Kconfig file selecting it, other than drivers/of/Kconfig which selects > OF_FLATTREE from OF_EARLY_FLATTREE. So as far as I can tell, the two > config options are essentially a single config option. Meaning that > either one could be replaced by the other. > > Changing all to OF_FLATTREE will touch more files and thus will be a > bit more obtrusive. It looks like it would take two releases to avoid > a flag day change. > > Changing all to OF_EARLY_FLATTREE can be done in a single release. I would get rid of OF_EARLY_FLATREE within the DT core code making it do nothing more than select OF_FLATTREE. Then the arches can later just select OF_FLATTREE directly. But this is all orthogonal to your issue. I think we need to keep the overlay dependencies on FDT separate. In theory we could support non-FDT sources or some more complex use that needs to unflatten FDT themselves. I don't really want to add another user visible kconfig option (OF_FDT_OVERLAY), so I think as long as we structure things to support that when needed we're fine. Rob -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
