diff mbox

[V2,1/7] kbuild: create an "include chroot" for DT bindings

Message ID 1365032098-22825-1-git-send-email-swarren@wwwdotorg.org (mailing list archive)
State New, archived
Headers show

Commit Message

Stephen Warren April 3, 2013, 11:34 p.m. UTC
From: Stephen Warren <swarren@nvidia.com>

The recent dtc+cpp support allows header files and C pre-processor
defines/macros to be used when compiling device tree files. These
headers will typically define various constants that are part of the
device tree bindings.

The original patch which set up the dtc+cpp include path only considered
using those headers from device tree files. However, most are also
useful for kernel code which needs to interpret the device tree.

In both the DT files and the kernel, I'd like to include the DT-related
headers in the same way, for example, <dt-bindings/gpio/tegra-gpio.h>.
That will simplify any text which discusses the DT header locations.

Creating a <dt-bindings/> for kernel source to use is as simple as
placing files into include/dt-bindings/.

However, when compiling DT files, the include path should be restricted
so that only the dt-bindings path is available; arbitrary kernel headers
shouldn't be exposed. For this reason, create a specific include
directory for use by dtc+cpp, and symlink dt-bindings from there to the
actual location of include/dt-bindings/. For want of a better location,
place this "include chroot" into the existing dts/ directory.

arch/*/boot/dts/include/dt-bindings -> ../../../../../include/dt-bindings

Some headers used by device tree files may not be useful to the kernel;
they may be used simply to aid in constructing the DT file (e.g. macros
to create a node), but not define any information that the kernel needs
to share. These may be placed directly into arch/*/boot/dts/ along with
the DT files themselves.

Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Hiroshi Doyu <hdoyu@nvidia.com>
Acked-by: Michal Marek <mmarek@suse.cz>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
Grant, Rob, Michal, I'm hoping for acks or comments from you so this
series can be placed into a topic branch in the arm-soc repo, for others
to build on during the 3.10 kernel cycle. Thanks.

This first patch was previously posted separately as V2. I'm including
it here to keep it with the whole series. I hope this series can be
applied as a topic branch in arm-soc.
---
 arch/arm/boot/dts/include/dt-bindings |    1 +
 scripts/Makefile.lib                  |    2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)
 create mode 120000 arch/arm/boot/dts/include/dt-bindings

Comments

Rob Herring April 4, 2013, 11:17 p.m. UTC | #1
On 04/03/2013 06:34 PM, Stephen Warren wrote:
> From: Stephen Warren <swarren@nvidia.com>
> 
> The recent dtc+cpp support allows header files and C pre-processor
> defines/macros to be used when compiling device tree files. These
> headers will typically define various constants that are part of the
> device tree bindings.
> 
> The original patch which set up the dtc+cpp include path only considered
> using those headers from device tree files. However, most are also
> useful for kernel code which needs to interpret the device tree.
> 
> In both the DT files and the kernel, I'd like to include the DT-related
> headers in the same way, for example, <dt-bindings/gpio/tegra-gpio.h>.
> That will simplify any text which discusses the DT header locations.
> 
> Creating a <dt-bindings/> for kernel source to use is as simple as
> placing files into include/dt-bindings/.
> 
> However, when compiling DT files, the include path should be restricted
> so that only the dt-bindings path is available; arbitrary kernel headers
> shouldn't be exposed. For this reason, create a specific include
> directory for use by dtc+cpp, and symlink dt-bindings from there to the
> actual location of include/dt-bindings/. For want of a better location,
> place this "include chroot" into the existing dts/ directory.
> 
> arch/*/boot/dts/include/dt-bindings -> ../../../../../include/dt-bindings
> 
> Some headers used by device tree files may not be useful to the kernel;
> they may be used simply to aid in constructing the DT file (e.g. macros
> to create a node), but not define any information that the kernel needs
> to share. These may be placed directly into arch/*/boot/dts/ along with
> the DT files themselves.
> 
> Cc: Shawn Guo <shawn.guo@linaro.org>
> Cc: Hiroshi Doyu <hdoyu@nvidia.com>
> Acked-by: Michal Marek <mmarek@suse.cz>
> Acked-by: Shawn Guo <shawn.guo@linaro.org>
> Acked-by: Rob Herring <rob.herring@calxeda.com>
> Signed-off-by: Stephen Warren <swarren@nvidia.com>
> ---
> Grant, Rob, Michal, I'm hoping for acks or comments from you so this
> series can be placed into a topic branch in the arm-soc repo, for others
> to build on during the 3.10 kernel cycle. Thanks.

Well, you have mine here and the rest looks fine, so add it to the others.

Rob

> 
> This first patch was previously posted separately as V2. I'm including
> it here to keep it with the whole series. I hope this series can be
> applied as a topic branch in arm-soc.
> ---
>  arch/arm/boot/dts/include/dt-bindings |    1 +
>  scripts/Makefile.lib                  |    2 +-
>  2 files changed, 2 insertions(+), 1 deletion(-)
>  create mode 120000 arch/arm/boot/dts/include/dt-bindings
> 
> diff --git a/arch/arm/boot/dts/include/dt-bindings b/arch/arm/boot/dts/include/dt-bindings
> new file mode 120000
> index 0000000..08c00e4
> --- /dev/null
> +++ b/arch/arm/boot/dts/include/dt-bindings
> @@ -0,0 +1 @@
> +../../../../../include/dt-bindings
> \ No newline at end of file
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index 07125e6..af35521 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -158,7 +158,7 @@ ld_flags       = $(LDFLAGS) $(ldflags-y)
>  
>  dtc_cpp_flags  = -Wp,-MD,$(depfile) -nostdinc                            \
>  		 -I$(srctree)/arch/$(SRCARCH)/boot/dts                   \
> -		 -I$(srctree)/arch/$(SRCARCH)/include/dts                \
> +		 -I$(srctree)/arch/$(SRCARCH)/boot/dts/include           \
>  		 -undef -D__DTS__
>  
>  # Finds the multi-part object the current object will be linked into
> 

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Stephen Warren April 5, 2013, 1:01 a.m. UTC | #2
On 04/04/2013 05:17 PM, Rob Herring wrote:
> On 04/03/2013 06:34 PM, Stephen Warren wrote:
>> From: Stephen Warren <swarren@nvidia.com>
>>
>> The recent dtc+cpp support allows header files and C pre-processor
>> defines/macros to be used when compiling device tree files. These
>> headers will typically define various constants that are part of the
>> device tree bindings.
>>
>> The original patch which set up the dtc+cpp include path only considered
>> using those headers from device tree files. However, most are also
>> useful for kernel code which needs to interpret the device tree.
>>
>> In both the DT files and the kernel, I'd like to include the DT-related
>> headers in the same way, for example, <dt-bindings/gpio/tegra-gpio.h>.
>> That will simplify any text which discusses the DT header locations.
>>
>> Creating a <dt-bindings/> for kernel source to use is as simple as
>> placing files into include/dt-bindings/.
>>
>> However, when compiling DT files, the include path should be restricted
>> so that only the dt-bindings path is available; arbitrary kernel headers
>> shouldn't be exposed. For this reason, create a specific include
>> directory for use by dtc+cpp, and symlink dt-bindings from there to the
>> actual location of include/dt-bindings/. For want of a better location,
>> place this "include chroot" into the existing dts/ directory.
>>
>> arch/*/boot/dts/include/dt-bindings -> ../../../../../include/dt-bindings
>>
>> Some headers used by device tree files may not be useful to the kernel;
>> they may be used simply to aid in constructing the DT file (e.g. macros
>> to create a node), but not define any information that the kernel needs
>> to share. These may be placed directly into arch/*/boot/dts/ along with
>> the DT files themselves.
>>
>> Cc: Shawn Guo <shawn.guo@linaro.org>
>> Cc: Hiroshi Doyu <hdoyu@nvidia.com>
>> Acked-by: Michal Marek <mmarek@suse.cz>
>> Acked-by: Shawn Guo <shawn.guo@linaro.org>
>> Acked-by: Rob Herring <rob.herring@calxeda.com>
>> Signed-off-by: Stephen Warren <swarren@nvidia.com>
>> ---
>> Grant, Rob, Michal, I'm hoping for acks or comments from you so this
>> series can be placed into a topic branch in the arm-soc repo, for others
>> to build on during the 3.10 kernel cycle. Thanks.
> 
> Well, you have mine here and the rest looks fine, so add it to the others.

Rob,

I had originally hoped for this to go into an arm-soc branch so that a
number of SoCs could convert to use the feature in the same release,
hence I was looking for acks to let that happen.

However, it's too late in the 3.10 cycle now for that to happen. Can the
series be applied to the DT tree instead; people can convert during the
3.11 cycle.
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Rob Herring April 5, 2013, 4:06 p.m. UTC | #3
On 04/04/2013 08:01 PM, Stephen Warren wrote:
> On 04/04/2013 05:17 PM, Rob Herring wrote:
>> On 04/03/2013 06:34 PM, Stephen Warren wrote:
>>> From: Stephen Warren <swarren@nvidia.com>
>>>
>>> The recent dtc+cpp support allows header files and C pre-processor
>>> defines/macros to be used when compiling device tree files. These
>>> headers will typically define various constants that are part of the
>>> device tree bindings.
>>>
>>> The original patch which set up the dtc+cpp include path only considered
>>> using those headers from device tree files. However, most are also
>>> useful for kernel code which needs to interpret the device tree.
>>>
>>> In both the DT files and the kernel, I'd like to include the DT-related
>>> headers in the same way, for example, <dt-bindings/gpio/tegra-gpio.h>.
>>> That will simplify any text which discusses the DT header locations.
>>>
>>> Creating a <dt-bindings/> for kernel source to use is as simple as
>>> placing files into include/dt-bindings/.
>>>
>>> However, when compiling DT files, the include path should be restricted
>>> so that only the dt-bindings path is available; arbitrary kernel headers
>>> shouldn't be exposed. For this reason, create a specific include
>>> directory for use by dtc+cpp, and symlink dt-bindings from there to the
>>> actual location of include/dt-bindings/. For want of a better location,
>>> place this "include chroot" into the existing dts/ directory.
>>>
>>> arch/*/boot/dts/include/dt-bindings -> ../../../../../include/dt-bindings
>>>
>>> Some headers used by device tree files may not be useful to the kernel;
>>> they may be used simply to aid in constructing the DT file (e.g. macros
>>> to create a node), but not define any information that the kernel needs
>>> to share. These may be placed directly into arch/*/boot/dts/ along with
>>> the DT files themselves.
>>>
>>> Cc: Shawn Guo <shawn.guo@linaro.org>
>>> Cc: Hiroshi Doyu <hdoyu@nvidia.com>
>>> Acked-by: Michal Marek <mmarek@suse.cz>
>>> Acked-by: Shawn Guo <shawn.guo@linaro.org>
>>> Acked-by: Rob Herring <rob.herring@calxeda.com>
>>> Signed-off-by: Stephen Warren <swarren@nvidia.com>
>>> ---
>>> Grant, Rob, Michal, I'm hoping for acks or comments from you so this
>>> series can be placed into a topic branch in the arm-soc repo, for others
>>> to build on during the 3.10 kernel cycle. Thanks.
>>
>> Well, you have mine here and the rest looks fine, so add it to the others.
> 
> Rob,
> 
> I had originally hoped for this to go into an arm-soc branch so that a
> number of SoCs could convert to use the feature in the same release,
> hence I was looking for acks to let that happen.
> 
> However, it's too late in the 3.10 cycle now for that to happen. Can the
> series be applied to the DT tree instead; people can convert during the
> 3.11 cycle.

That is fine. Can you send me a pull request.

Rob


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Grant Likely April 19, 2013, 10:01 a.m. UTC | #4
On Wed,  3 Apr 2013 17:34:52 -0600, Stephen Warren <swarren@wwwdotorg.org> wrote:
> Grant, Rob, Michal, I'm hoping for acks or comments from you so this
> series can be placed into a topic branch in the arm-soc repo, for others
> to build on during the 3.10 kernel cycle. Thanks.

Thanks for doing all this work Stephen. It looks really good.

g.
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diff mbox

Patch

diff --git a/arch/arm/boot/dts/include/dt-bindings b/arch/arm/boot/dts/include/dt-bindings
new file mode 120000
index 0000000..08c00e4
--- /dev/null
+++ b/arch/arm/boot/dts/include/dt-bindings
@@ -0,0 +1 @@ 
+../../../../../include/dt-bindings
\ No newline at end of file
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 07125e6..af35521 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -158,7 +158,7 @@  ld_flags       = $(LDFLAGS) $(ldflags-y)
 
 dtc_cpp_flags  = -Wp,-MD,$(depfile) -nostdinc                            \
 		 -I$(srctree)/arch/$(SRCARCH)/boot/dts                   \
-		 -I$(srctree)/arch/$(SRCARCH)/include/dts                \
+		 -I$(srctree)/arch/$(SRCARCH)/boot/dts/include           \
 		 -undef -D__DTS__
 
 # Finds the multi-part object the current object will be linked into