Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752440AbdHPW53 (ORCPT ); Wed, 16 Aug 2017 18:57:29 -0400 Received: from mail-pg0-f66.google.com ([74.125.83.66]:34463 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752339AbdHPW51 (ORCPT ); Wed, 16 Aug 2017 18:57:27 -0400 Subject: Re: [PATCH] ARM: dts: TI: Enable __symbols__ in dtb files for some platforms To: Tom Rini , devicetree@vger.kernel.org References: <1502920751-11121-1-git-send-email-trini@konsulko.com> <5994C81C.609@gmail.com> Cc: Tero Kristo , Nishanth Menon , Tomi Valkeinen , Sekhar Nori , Jason Kridner , Drew Fustini , Robert Nelson , Lokesh Vutla , Rob Herring , Mark Rutland , Russell King , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org From: Frank Rowand Message-ID: <5994CDD1.9050708@gmail.com> Date: Wed, 16 Aug 2017 15:57:21 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: <5994C81C.609@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3291 Lines: 80 On 08/16/17 15:33, Frank Rowand wrote: > On 08/16/17 14:59, Tom Rini wrote: >> Build the dtb file for these platfroms with __symbol__ information >> included. This will reduce the size of the dtb (and resident memory > > typo: reduce the size should be increase the size > > >> usage) in exchange for allowing more types of overlays to be applied to >> the dtb file prior to passing it to Linux and additional functionality >> within the kernel when OF_OVERLAY is enabled. >> >> Cc: Jason Kridner >> Cc: Drew Fustini >> Cc: Robert Nelson >> Cc: Lokesh Vutla >> Cc: Frank Rowand >> Cc: Rob Herring >> Cc: Mark Rutland >> Cc: Russell King >> Cc: devicetree@vger.kernel.org >> Cc: linux-arm-kernel@lists.infradead.org >> Cc: linux-kernel@vger.kernel.org >> Signed-off-by: Tom Rini >> --- >> This patch takes the path that Rob encouraged in my previous patch of >> enabling __symbols__ in some platforms now (that can use it) and see if >> a critical mass evolves that pushes towards -@ being default for all >> dtbs. I would suggest that the dra76 series be respun to include a hunk >> like this at least as well, and if there's another Beagle X15 patch, >> that too. Russell, per some of our conversations, something like would >> also be needed as part of using overlays to solve some of the problems >> with Hummingboard, etc. >> --- >> arch/arm/boot/dts/Makefile | 14 ++++++++++++++ >> 1 file changed, 14 insertions(+) >> >> diff --git a/arch/arm/boot/dts/Makefile b/arch/arm/boot/dts/Makefile >> index 4b17f35dc9a7..6f98422ca00e 100644 >> --- a/arch/arm/boot/dts/Makefile >> +++ b/arch/arm/boot/dts/Makefile >> @@ -1063,3 +1063,17 @@ dtb-$(CONFIG_OF_ALL_DTBS) := $(patsubst $(dtstree)/%.dts,%.dtb, $(wildcard $(dts >> >> always := $(dtb-y) >> clean-files := *.dtb >> + >> +# enable creation of __symbols__ node >> +DTC_FLAGS_am335x-bone += -@ >> +DTC_FLAGS_am335x-boneblack += -@ >> +DTC_FLAGS_am335x-boneblack-wireless += -@ >> +DTC_FLAGS_am335x-boneblue += -@ >> +DTC_FLAGS_am335x-bonegreen += -@ >> +DTC_FLAGS_am335x-bonegreen-wireless += -@ >> +DTC_FLAGS_am57xx-beagle-x15 += -@ >> +DTC_FLAGS_am57xx-beagle-x15-revb1 += -@ >> +DTC_FLAGS_dra7-evm += -@ >> +DTC_FLAGS_dra72-evm += -@ >> +DTC_FLAGS_dra72-evm-revc += -@ >> +DTC_FLAGS_dra71-evm += -@ >> > > I would prefer that instead of "-@", a configurable value be used. I stated that poorly. It was intended conceptually, not literally. One possible concrete implementation would be to use something other than DTC_FLAGS, for example DTC_FLAGS_EXTRA, then have the build system choose whether to fold DTC_FLAGS_EXTRA into DTC_FLAGS, based on some sort of configurable value. > The current form of the patch imposes the extra overhead even > for those who do not want to use any overlay. > > Using a kernel CONFIG_ value for the "configurable value" is not > desired because it adds a kernel configuration dependency to what > is contained in a dtb. I do not know if we can find another > better way to make this configurable. AMaybe Rob's suggestion > of a shell variable used in the make command. >