[OE-core] [PATCH] linux-dtb: Use kernel build system to generate the dtb files
Otavio Salvador
otavio at ossystems.com.br
Tue Aug 13 13:35:40 UTC 2013
On Tue, Aug 13, 2013 at 10:06 AM, Bruce Ashfield
<bruce.ashfield at windriver.com> wrote:
> On 13-08-13 08:46 AM, Otavio Salvador wrote:
>>
>> On Tue, Aug 13, 2013 at 12:40 AM, Bruce Ashfield
>> <bruce.ashfield at windriver.com> wrote:
>>>
>>> On 13-08-12 11:37 AM, Otavio Salvador wrote:
>>>>
>>>>
>>>> As the Linux kernel, unconditionally, builds the dtc application and
>>>> it is the compatible version with the DeviceTree files shipped within
>>>> the kernel it is better to use it and the kernel build system to
>>>> generate the dtb files.
>>>
>>>
>>>
>>> From my point of view, I agree with this. I've always pushed for using
>>> all of the artifacts from the kernel built (uImage, dtb, etc) and this
>>> is consistent with that approach.
>>
>>
>> Good.
>>
>>>> Some DeviceTree files rely on CPP and kernel headers to be able to
>>>> generate the dtb binary contents and it is harder to replicate it
>>>> outside of Linux kernel build system so we /use/ it.
>>>>
>>>> Signed-off-by: Otavio Salvador <otavio at ossystems.com.br>
>>>> ---
>>>> NOTE: This depends on 'linux-dtb.inc: Replace /boot/ with
>>>> /${KERNEL_IMAGEDEST}/' patch
>>>>
>>>> meta/recipes-kernel/linux/linux-dtb.inc | 59
>>>> +++++++++++++++------------------
>>>> 1 file changed, 27 insertions(+), 32 deletions(-)
>>>>
>>>> diff --git a/meta/recipes-kernel/linux/linux-dtb.inc
>>>> b/meta/recipes-kernel/linux/linux-dtb.inc
>>>> index 41dd599..a65f8bd 100644
>>>> --- a/meta/recipes-kernel/linux/linux-dtb.inc
>>>> +++ b/meta/recipes-kernel/linux/linux-dtb.inc
>>>> @@ -1,44 +1,39 @@
>>>> # Support for device tree generation
>>>> FILES_kernel-devicetree = "/${KERNEL_IMAGEDEST}/devicetree*"
>>>> -KERNEL_DEVICETREE_FLAGS ?= "-R 8 -p 0x3000"
>>>>
>>>> python __anonymous () {
>>>> - devicetree = d.getVar("KERNEL_DEVICETREE", True) or ''
>>>> - if devicetree:
>>>> - depends = d.getVar("DEPENDS", True)
>>>> - d.setVar("DEPENDS", "%s dtc-native" % depends)
>>>> - packages = d.getVar("PACKAGES", True)
>>>> - d.setVar("PACKAGES", "%s kernel-devicetree" % packages)
>>>> + d.appendVar("PACKAGES", " kernel-devicetree")
>>>
>>>
>>>
>>> What if someone, somewhere needs a custom dtc. Can we still trigger
>>> a dependency on dtc-native is a different flag is set ?
>>
>>
>> The Kernel does not provide a way to 'override' it; it always use it
>> from scripts/dtc and it is the compatible version with the DeviceTree
>> files shipped within the kernel, so it is better to use it and the
>> kernel build system to generate the dtb files.
>
>
> What I meant was not to override the kernel's dtc, but to simply fall
> back to the old dtc-native reaching into the tree and compiling the
> dts. That way we have flexibility as a fall back.
I think it will make the code much harder to follow and I am unsure we
will have it in a flexible enough way; for example if user uses kernel
headers for pins and like, it won't work, and it will be hard to come
up with something which could comply with all this. As this .inc file
is intended for 'in kernel build' it does not seems worth it.
>>>> }
>>>>
>>>> do_install_append() {
>>>> + bbwarn "ARRG"
>>>> if test -n "${KERNEL_DEVICETREE}"; then
>>>> - for DTS_FILE in ${KERNEL_DEVICETREE}; do
>>>> - if [ ! -f ${DTS_FILE} ]; then
>>>> - echo "Warning: ${DTS_FILE} is not
>>>> available!"
>>>> - continue
>>>> + for DTB in ${KERNEL_DEVICETREE}; do
>>>> + if echo ${DTB} | grep -q '/dts/'; then
>>>> + bbwarn "${DTB} points to the full path
>>>> dts
>>>> file while it should have the target for use."
>>>
>>>
>>>
>>> This isn't reading right to me. What are you trying to say ? That
>>> KERNEL_DEVICE_TREE should be the name of the dts and not the path
>>> to that dts ? I'd say 'name' versus target.
>>
>>
>> You should name it 'imx6q-sabresd.dtb' for example.
>
>
> right, that's what I always do myself. So I'm really just suggesting that
> the bbwarn message be a bit more clear. i.e.
>
> bbwarn "${DTB} contains the full path to the the dts file, but only the
> dtb name should be used."
Great; changed for v2
>>> What about testing for it's existence ? The old code used to do that.
>>
>>
>> It will fail if you ask it to build an invalid dtb file.
>>
>>>> + DTB=`basename ${DTB} | sed
>>>> 's,\.dts$,.dtb,g'`
>>>
>>>
>>>
>>> From the description of the patch .. this part is unexpected.
>>> You are changing more than what is used to compile the dtb,
>>> but the processing of the options.
>>
>>
>> It is not; I need to call it with the target. This is to support
>> converting from 'current' use to 'new' use and keep backward
>> compatibility.
>
>
> Right, so you are switching to dtb, which the kernel expects, not
> dts. The commit message should make this clear, right now it
> doesn't. You need to understand what the kernel is looking for to
> know why the change is being made.
Ok; Changed for v2.
>>>> fi
>>>> - DTS_BASE_NAME=`basename ${DTS_FILE} | awk -F "."
>>>> '{print $1}'`
>>>> - DTB_NAME=`echo ${KERNEL_IMAGE_BASE_NAME} | sed
>>>> "s/${MACHINE}/${DTS_BASE_NAME}/g"`
>>>> - DTB_SYMLINK_NAME=`echo
>>>> ${KERNEL_IMAGE_SYMLINK_NAME} | sed "s/${MACHINE}/${DTS_BASE_NAME}/g"`
>>>> - dtc -I dts -O dtb ${KERNEL_DEVICETREE_FLAGS} -o
>>>> ${DTS_BASE_NAME} ${DTS_FILE}
>>>> - install -m 0644 ${DTS_BASE_NAME}
>>>> ${D}/${KERNEL_IMAGEDEST}/devicetree-${DTB_SYMLINK_NAME}.dtb
>>>> + DTB_BASE_NAME=`basename ${DTB} .dtb`
>>>> + DTB_NAME=`echo ${KERNEL_IMAGE_BASE_NAME} | sed
>>>> "s/${MACHINE}/${DTB_BASE_NAME}/g"`
>>>> + DTB_SYMLINK_NAME=`echo
>>>> ${KERNEL_IMAGE_SYMLINK_NAME} | sed "s/${MACHINE}/${DTB_BASE_NAME}/g"`
>>>> + oe_runmake ${DTB}
>>>
>>>
>>>
>>> The change log should explain this as well. You are switching the
>>> naming to DTB from the old DTS .. because ? The kernel build
>>> requires it ? something else ? You tell me :)
>>
>>
>> This is to support converting from 'current' use to 'new' use and keep
>> backward compatibility.
>>
>>>> + install -m 0644 ${B}/arch/${ARCH}/boot/${DTB}
>>>> ${D}/${KERNEL_IMAGEDEST}/devicetree-${DTB_SYMLINK_NAME}.dtb
>>>> done
>>>> fi
>>>> }
>>>>
>>>> do_deploy_append() {
>>>> if test -n "${KERNEL_DEVICETREE}"; then
>>>> - for DTS_FILE in ${KERNEL_DEVICETREE}; do
>>>> - if [ ! -f ${DTS_FILE} ]; then
>>>> - echo "Warning: ${DTS_FILE} is not
>>>> available!"
>>>> - continue
>>>> + for DTB in ${KERNEL_DEVICETREE}; do
>>>> + if echo ${DTB} | grep -q '/dts/'; then
>>>> + bbwarn "${DTB} points to the full path
>>>> dts
>>>> file while it should have the target for use. "
>>>> + DTB=`basename ${DTB} | sed
>>>> 's,\.dts$,.dtb,g'`
>>>
>>>
>>>
>>> Given that the old and new code repeats this block .. is there an
>>> opportunity to factor it out into a function ?
>>
>>
>> In a new patch?
>
>
> Could be, or just as part of this one. Either way works.
Ok; I will take a look on that.
--
Otavio Salvador O.S. Systems
http://www.ossystems.com.br http://projetos.ossystems.com.br
Mobile: +55 (53) 9981-7854 Mobile: +1 (347) 903-9750
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