[Buildroot] [PATCH 2/4] Add support for appended device tree blobs for arm

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Le Tue,  3 Jul 2012 12:01:14 +0200,
Maxime Ripard <maxime.ripard@free-electrons.com> a ?crit :

> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> ---
>  linux/Config.in |    8 ++++++++
>  linux/linux.mk  |   38 +++++++++++++++++++++++++++++++++++++-
>  2 files changed, 45 insertions(+), 1 deletion(-)
> 
> diff --git a/linux/Config.in b/linux/Config.in
> index 6f704b0..46b9756 100644
> --- a/linux/Config.in
> +++ b/linux/Config.in
> @@ -132,6 +132,14 @@ config BR2_LINUX_KERNEL_DTS_SUPPORT
>  
>  if BR2_LINUX_KERNEL_DTS_SUPPORT
>  
> +config BR2_LINUX_KERNEL_APPENDED_DTB
> +	bool "Append the Device Tree binary to the kernel"

				Blob

> +	depends on BR2_arm || BR2_armeb
> +	help
> +	  After building the device tree blob, append it to the
> +	  kernel image. If necessary generates a uImage from that
> +	  new kernel image afterward.

This should rather be *after* the Device Tree Source choice and
selection, in my opinion. It would be more logical: (1) what I include,
(2) how I include it.

>  choice
>  	prompt "Device tree source"
>  	default BR2_LINUX_KERNEL_USE_DEFAULT_DTS
> diff --git a/linux/linux.mk b/linux/linux.mk
> index 0540aeb..483974c 100644
> --- a/linux/linux.mk
> +++ b/linux/linux.mk
> @@ -52,6 +52,13 @@ else ifeq ($(BR2_LINUX_KERNEL_USE_CUSTOM_DTS),y)
>  KERNEL_DTS_NAME = $(basename $(notdir $(BR2_LINUX_KERNEL_CUSTOM_DTS_FILE)))
>  endif
>  
> +ifeq ($(BR2_LINUX_KERNEL_APPENDED_DTB),y)
> +ifneq ($(words $(KERNEL_DTS_NAME)),1)
> +$(error Kernel with appended device tree needs exactly one DTS source.\
> +  Check BR2_LINUX_KERNEL_DTS_FILE or BR2_LINUX_KERNEL_CUSTOM_DTS_FILE.)
> +endif
> +endif
> +
>  ifeq ($(BR2_LINUX_KERNEL_IMAGE_TARGET_CUSTOM),y)
>  LINUX_IMAGE_NAME=$(call qstrip,$(BR2_LINUX_KERNEL_IMAGE_TARGET_NAME))
>  else
> @@ -76,6 +83,12 @@ LINUX_IMAGE_NAME=vmlinuz
>  endif
>  endif
>  
> +ifeq ($(BR2_LINUX_KERNEL_APPENDED_DTB),y)
> +LINUX_IMAGE_TARGET=zImage
> +else
> +LINUX_IMAGE_TARGET=$(LINUX_IMAGE_NAME)
> +endif
> +
>  # Compute the arch path, since i386 and x86_64 are in arch/x86 and not
>  # in arch/$(KERNEL_ARCH). Even if the kernel creates symbolic links
>  # for bzImage, arch/i386 and arch/x86_64 do not exist when copying the
> @@ -155,6 +168,8 @@ define LINUX_CONFIGURE_CMDS
>  		$(call KCONFIG_SET_OPT,CONFIG_UEVENT_HELPER_PATH,\"/sbin/mdev\",$(@D)/.config))
>  	$(if $(BR2_PACKAGE_SYSTEMD),
>  		$(call KCONFIG_ENABLE_OPT,CONFIG_CGROUPS,$(@D)/.config))
> +	$(if $(BR2_LINUX_KERNEL_APPENDED_DTB),
> +		$(call KCONFIG_ENABLE_OPT,CONFIG_ARM_APPENDED_DTB,$(@D)/.config))
>  	yes '' | $(TARGET_MAKE_ENV) $(MAKE1) $(LINUX_MAKE_FLAGS) -C $(@D) oldconfig
>  endef
>  
> @@ -164,17 +179,38 @@ define LINUX_BUILD_DTB
>  endef
>  endif
>  
> +ifeq ($(BR2_LINUX_KERNEL_APPENDED_DTB),y)
> +ifeq ($(BR2_LINUX_KERNEL_UBOOT_IMAGE),y)
> +define LINUX_APPEND_DTB
> +	cat $(KERNEL_ARCH_PATH)/boot/zImage $(KERNEL_ARCH_PATH)/boot/$(KERNEL_DTS_NAME).dtb > $(KERNEL_ARCH_PATH)/boot/zImage_dtb
> +	mv $(KERNEL_ARCH_PATH)/boot/zImage_dtb $(KERNEL_ARCH_PATH)/boot/zImage
> +	LOAD=`$(MKIMAGE) -l $(LINUX_IMAGE_PATH) | sed -n 's/Load Address: \([0-9]*\)/\1/p'`; \
> +	ENTRY=`$(MKIMAGE) -l $(LINUX_IMAGE_PATH) | sed -n 's/Entry Point: \([0-9]*\)/\1/p'`; \
> +	$(MKIMAGE) -A $(KERNEL_ARCH) -O linux -T kernel -C none -a $${LOAD} -e $${ENTRY} -n 'Linux Buildroot' \
> +		-d $(KERNEL_ARCH_PATH)/boot/zImage $(KERNEL_ARCH_PATH)/boot/$(LINUX_IMAGE_NAME)
> +endef
> +else ifeq ($(BR2_LINUX_KERNEL_ZIMAGE),y)
> +define LINUX_APPEND_DTB
> +	cat $(KERNEL_ARCH_PATH)/boot/zImage $(KERNEL_ARCH_PATH)/boot/$(KERNEL_DTS_NAME).dtb > $(KERNEL_ARCH_PATH)/boot/zImage_dtb
> +	mv $(KERNEL_ARCH_PATH)/boot/zImage_dtb $(KERNEL_ARCH_PATH)/boot/zImage
> +endef
> +else
> +$(error Appending DTB to the kernel image is only possible for u-boot images and zImage.)

Can't this be verified at the Kconfig level instead.

> +endif
> +endif

A big comment on top of this mkimage magic would be necessary.

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com