On 2/19/2014 1:15 PM, Grant Likely wrote: > On Wed, Feb 19, 2014 at 8:16 PM, Frank Rowand <frowand.list@xxxxxxxxx> wrote: >> On 2/19/2014 1:08 AM, Sascha Hauer wrote: >>> On Tue, Feb 18, 2014 at 02:44:15PM -0800, Tim Bird wrote: >>>> I'm not in favor of separating the device tree information from the kernel. >>>> >>>> If we switch, then whatever synchronization issues other projects >>>> are having now with synching with the device tree info from the kernel will >>>> just then become the problem of the kernel developers, who will then >>>> have to sync with the device tree info from another repository. If the >>>> sync issues can't be solved now for them, why or how would it be solved >>>> post-separation for us? (It sounds like a zero-sum game of pain transfer >>>> to me.) >>>> >>>> I'm relatively unfamiliar with the arguments. Can someone provide >>>> a brief list of reasons this is needed, and how the inconvenience to Linux >>>> kernel developers will be minimized, should it proceed? >>> >> >> >>> One of the reasons for doing devicetrees is to separate the hardware >>> description from the code so that: >>> - Other OSes (and bootloaders) can use the same description to start on >>> a given hardware >>> - A generic Kernel can be started on any hardware >>> - A hardware describes itself, makes itself more introspecitve so we can >>> go away from very specialized kernels >> >> Tim knows this ^^^^. He was asking for the arguments for moving dts files >> out of the linux kernel source tree. > > We've made the decision that devicetree bindings need to be treated as > ABI, but as long as the .dts files live in the kernel there will > always be the temptation to just tweak things in lock-step and nobody > will notice. Splitting the files out gives that extra push to think > about whether changes to a binding will backwards compatible with a > tree that doesn't have those changes because the chances are a lot > higher that someone will hit that combination. > > The other argument is shared source between > BSD/U-Boot/Barebox/Linux/etc. Until we have a separate .dts repo there > is no good way to share the database of hardware descriptions. We could provide an easy export (see below). What do you think? -Frank Proof of concept: export devicetree source and header files Not-signed-off-by: Frank Rowand <frank.rowand@xxxxxxxxxxxxxx> --- Makefile | 27 26 + 1 - 0 ! scripts/Makefile.dtsexport | 19 19 + 0 - 0 ! scripts/dts.sh | 11 11 + 0 - 0 ! 3 files changed, 56 insertions(+), 1 deletion(-) Index: b/Makefile =================================================================== --- a/Makefile +++ b/Makefile @@ -234,6 +234,9 @@ endif # Where to locate arch specific headers hdr-arch := $(SRCARCH) +# Where to locate arch specific dts +dts-arch := $(SRCARCH) + KCONFIG_CONFIG ?= .config export KCONFIG_CONFIG @@ -463,7 +466,7 @@ version_h := include/generated/uapi/linu no-dot-config-targets := clean mrproper distclean \ cscope gtags TAGS tags help %docs check% coccicheck \ $(version_h) headers_% archheaders archscripts \ - kernelversion %src-pkg + kernelversion %src-pkg dts_export% config-targets := 0 mixed-targets := 0 @@ -933,6 +936,26 @@ firmware_install: FORCE $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.fwinst obj=firmware __fw_install # --------------------------------------------------------------------------- +# devicetree source and headers export + +#Default location for installed headers +export EXPORT_DTS_PATH = $(KBUILD_OUTPUT)/usr/dts + +PHONY += dts_export_headers +dts_export_headers: scripts_basic + $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.dtsexport obj=include/dt-bindings + @echo $(KERNELRELEASE) >$(EXPORT_DTS_PATH)/linux_version + +PHONY += dts_export_all +dts_export_all: dts_export_headers + $(Q)$(CONFIG_SHELL) $(srctree)/scripts/dts.sh + +PHONY += dts_export +dts_export: + $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.dtsexport obj=arch/$(dts-arch)/boot/dts + + +# --------------------------------------------------------------------------- # Kernel headers #Default location for installed headers @@ -1160,6 +1183,8 @@ help: @echo ' modules_prepare - Set up for building external modules' @echo ' tags/TAGS - Generate tags file for editors' @echo ' cscope - Generate cscope index' + @echo ' dts_export_all - Export devicetree source and headers to EXPORT_DTS_PATH' + @echo ' (default: $(EXPORT_DTS_PATH))' @echo ' gtags - Generate GNU GLOBAL index' @echo ' kernelrelease - Output the release version string' @echo ' kernelversion - Output the version stored in Makefile' Index: b/scripts/Makefile.dtsexport =================================================================== --- /dev/null +++ b/scripts/Makefile.dtsexport @@ -0,0 +1,19 @@ +# ========================================================================== +# Exporting dts source and header files +# +# ========================================================================== + +srcpath := $(srctree)/$(obj)/* +dstpath := $(EXPORT_DTS_PATH)/$(obj) + +include scripts/Kbuild.include + + +quiet_cmd_install = EXPORT $(subst $(srctree)/,,$(srcpath)) + cmd_install = mkdir -p $(dstpath); cp -a $(srcpath) $(dstpath) + + +.PHONY: export +export: + $(call cmd,install) + Index: b/scripts/dts.sh =================================================================== --- /dev/null +++ b/scripts/dts.sh @@ -0,0 +1,11 @@ +#!/bin/sh +# Run dts_export command for all architectures + +# Stop on error +set -e + +for arch in $(ls ${srctree}/arch); do + if [ -d ${srctree}/arch/${arch}/boot/dts ]; then + make ARCH=${arch} dts_export + fi +done -- To unsubscribe from this list: send the line "unsubscribe devicetree-compiler" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html