[PATCH] dtc: Use quotes to include header files

[PATCH] dtc: Use quotes to include header files

[Chris Packham]

Currently in arch and driver code that needs early access to the
flattened device tree it is necessary to add specific CFLAGS so that
when scripts/dtc/libfdt/libfdt.h is included the C preprocessor is able
to locate the libfdt versions of libfdt_env.h and fdt.h without
generating an error.

We already provide an alternative linux-specific
version of libfdt_env.h and directly include scripts/dtc/libfdt/fdt.h
so the inclusion by scripts/dtc/libfdt/libfdt.h is a no-op thanks to the
inclusion guards.

By using quotes in scripts/dtc/libfdt/libfdt.h it picks up fdt.h and
libfdt_env.h from the source directory without needing to add CFLAGS for
the sources that happen to include linux/libfdt.h.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---
Hi,

This probably should come via git://git.jdl.com/software/dtc.git however
this appears to be inaccessible at the moment. Is this still the
canonical source for the device tree compiler and libfdt or has it been
moved? How much deviation from the canonical source are we prepared to
live with in the kernel?

This came up on the arm-LKML[1]. Basically in the name of backwards
compatibility I need to add a .dt_fixup to add some required nodes to
the flattened device tree prior to the tree being un-flattened and
processed. This is a trick powerpc makes use of fairly extensively and
there are a few other instances of this.

For the files that include linux/libfdt.h we currently also have to
specify additional CFLAGS to satisfy the CPP.
    
  $ git grep '<linux/libfdt.h>'
  arch/mips/cavium-octeon/octeon-platform.c:#include <linux/libfdt.h>
  arch/mips/cavium-octeon/setup.c:#include <linux/libfdt.h>
  arch/mips/mti-sead3/sead3-setup.c:#include <linux/libfdt.h>
  arch/powerpc/kernel/prom.c:#include <linux/libfdt.h>
  drivers/firmware/efi/libstub/fdt.c:#include <linux/libfdt.h>
  drivers/of/fdt.c:#include <linux/libfdt.h>
  drivers/of/fdt_address.c:#include <linux/libfdt.h>

  $ git grep -e '-I.*dtc/libfdt'
  arch/mips/cavium-octeon/Makefile:CFLAGS_octeon-platform.o = -I$(src)/../../../scripts/dtc/libfdt
  arch/mips/cavium-octeon/Makefile:CFLAGS_setup.o = -I$(src)/../../../scripts/dtc/libfdt
  arch/mips/mti-sead3/Makefile:CFLAGS_sead3-setup.o = -I$(src)/../../../scripts/dtc/libfdt
  arch/powerpc/kernel/Makefile:CFLAGS_prom.o              = -I$(src)/../../../scripts/dtc/libfdt
  drivers/firmware/efi/libstub/Makefile:CFLAGS_fdt.o += -I$(srctree)/scripts/dtc/libfdt/
  drivers/of/Makefile:CFLAGS_fdt.o = -I$(src)/../../scripts/dtc/libfdt
  drivers/of/Makefile:CFLAGS_fdt_address.o = -I$(src)/../../scripts/dtc/libfdt
  lib/Makefile:   $(eval CFLAGS_$(file) = -I$(src)/../scripts/dtc/libfdt))
    
Simply by switching to using quotes we can avoid having this extra step.

Assuming that this patch is acceptable a follow on clean up would be to
remove the instances of CFLAGS_... listed above.

Regards,
Chris
--
[1] - http://lists.infradead.org/pipermail/linux-arm-kernel/2014-December/310840.html

 scripts/dtc/libfdt/libfdt.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/dtc/libfdt/libfdt.h b/scripts/dtc/libfdt/libfdt.h
index 73f4975..ea1ddcd 100644
--- a/scripts/dtc/libfdt/libfdt.h
+++ b/scripts/dtc/libfdt/libfdt.h
@@ -51,8 +51,8 @@
  *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <libfdt_env.h>
-#include <fdt.h>
+#include "libfdt_env.h"
+#include "fdt.h"
 
 #define FDT_FIRST_SUPPORTED_VERSION	0x10
 #define FDT_LAST_SUPPORTED_VERSION	0x11
-- 
2.2.0.rc0

Re: [PATCH] dtc: Use quotes to include header files

[Jon Loeliger]

So, like, Chris Packham said:
> Hi,
> 
> This probably should come via git://git.jdl.com/software/dtc.git however
> this appears to be inaccessible at the moment. Is this still the
> canonical source for the device tree compiler and libfdt or has it been
> moved? How much deviation from the canonical source are we prepared to
> live with in the kernel?

That is because the official DTC repository has moved to git.kernel.org!



> Currently in arch and driver code that needs early access to the
> flattened device tree it is necessary to add specific CFLAGS so that
> when scripts/dtc/libfdt/libfdt.h is included the C preprocessor is able
> to locate the libfdt versions of libfdt_env.h and fdt.h without
> generating an error.
> 
> We already provide an alternative linux-specific
> version of libfdt_env.h and directly include scripts/dtc/libfdt/fdt.h
> so the inclusion by scripts/dtc/libfdt/libfdt.h is a no-op thanks to the
> inclusion guards.
> 
> By using quotes in scripts/dtc/libfdt/libfdt.h it picks up fdt.h and
> libfdt_env.h from the source directory without needing to add CFLAGS for
> the sources that happen to include linux/libfdt.h.
> 
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> ---

and:

> diff --git a/scripts/dtc/libfdt/libfdt.h b/scripts/dtc/libfdt/libfdt.h
> index 73f4975..ea1ddcd 100644
> --- a/scripts/dtc/libfdt/libfdt.h
> +++ b/scripts/dtc/libfdt/libfdt.h
> @@ -51,8 +51,8 @@
>   *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
>   */
>  
> -#include <libfdt_env.h>
> -#include <fdt.h>
> +#include "libfdt_env.h"
> +#include "fdt.h"
>  
>  #define FDT_FIRST_SUPPORTED_VERSION	0x10
>  #define FDT_LAST_SUPPORTED_VERSION	0x11


Hmm.  I seem to recall that the use of angle brackets was intentional.
I believe that was predicated on installing the FDT library on some
target machine and needing it to be able to find the other header
files in an installation, not source, directory.

Minor repository spelunking suggests that the angle brackets have
been around since Day Zero:

    commit 3da0f9a10dfa9b615d06c350c7b9fe29f360a6e0

David?

HTH?,
jdl

Re: [PATCH] dtc: Use quotes to include header files

[Grant Likely]

On Tue, 16 Dec 2014 15:13:24 +1300
, Chris Packham <chris.packham@alliedtelesis.co.nz>
 wrote:
> Currently in arch and driver code that needs early access to the
> flattened device tree it is necessary to add specific CFLAGS so that
> when scripts/dtc/libfdt/libfdt.h is included the C preprocessor is able
> to locate the libfdt versions of libfdt_env.h and fdt.h without
> generating an error.
> 
> We already provide an alternative linux-specific
> version of libfdt_env.h and directly include scripts/dtc/libfdt/fdt.h
> so the inclusion by scripts/dtc/libfdt/libfdt.h is a no-op thanks to the
> inclusion guards.
> 
> By using quotes in scripts/dtc/libfdt/libfdt.h it picks up fdt.h and
> libfdt_env.h from the source directory without needing to add CFLAGS for
> the sources that happen to include linux/libfdt.h.
> 
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> ---
> Hi,
> 
> This probably should come via git://git.jdl.com/software/dtc.git however
> this appears to be inaccessible at the moment. Is this still the
> canonical source for the device tree compiler and libfdt or has it been
> moved? How much deviation from the canonical source are we prepared to
> live with in the kernel?
> 
> This came up on the arm-LKML[1]. Basically in the name of backwards
> compatibility I need to add a .dt_fixup to add some required nodes to
> the flattened device tree prior to the tree being un-flattened and
> processed. This is a trick powerpc makes use of fairly extensively and
> there are a few other instances of this.
> 
> For the files that include linux/libfdt.h we currently also have to
> specify additional CFLAGS to satisfy the CPP.
>     
>   $ git grep '<linux/libfdt.h>'
>   arch/mips/cavium-octeon/octeon-platform.c:#include <linux/libfdt.h>
>   arch/mips/cavium-octeon/setup.c:#include <linux/libfdt.h>
>   arch/mips/mti-sead3/sead3-setup.c:#include <linux/libfdt.h>
>   arch/powerpc/kernel/prom.c:#include <linux/libfdt.h>
>   drivers/firmware/efi/libstub/fdt.c:#include <linux/libfdt.h>
>   drivers/of/fdt.c:#include <linux/libfdt.h>
>   drivers/of/fdt_address.c:#include <linux/libfdt.h>
> 
>   $ git grep -e '-I.*dtc/libfdt'
>   arch/mips/cavium-octeon/Makefile:CFLAGS_octeon-platform.o = -I$(src)/../../../scripts/dtc/libfdt
>   arch/mips/cavium-octeon/Makefile:CFLAGS_setup.o = -I$(src)/../../../scripts/dtc/libfdt
>   arch/mips/mti-sead3/Makefile:CFLAGS_sead3-setup.o = -I$(src)/../../../scripts/dtc/libfdt
>   arch/powerpc/kernel/Makefile:CFLAGS_prom.o              = -I$(src)/../../../scripts/dtc/libfdt
>   drivers/firmware/efi/libstub/Makefile:CFLAGS_fdt.o += -I$(srctree)/scripts/dtc/libfdt/
>   drivers/of/Makefile:CFLAGS_fdt.o = -I$(src)/../../scripts/dtc/libfdt
>   drivers/of/Makefile:CFLAGS_fdt_address.o = -I$(src)/../../scripts/dtc/libfdt
>   lib/Makefile:   $(eval CFLAGS_$(file) = -I$(src)/../scripts/dtc/libfdt))
>     
> Simply by switching to using quotes we can avoid having this extra step.
> 
> Assuming that this patch is acceptable a follow on clean up would be to
> remove the instances of CFLAGS_... listed above.
> 
> Regards,
> Chris
> --
> [1] - http://lists.infradead.org/pipermail/linux-arm-kernel/2014-December/310840.html
> 
>  scripts/dtc/libfdt/libfdt.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/scripts/dtc/libfdt/libfdt.h b/scripts/dtc/libfdt/libfdt.h
> index 73f4975..ea1ddcd 100644
> --- a/scripts/dtc/libfdt/libfdt.h
> +++ b/scripts/dtc/libfdt/libfdt.h
> @@ -51,8 +51,8 @@
>   *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
>   */
>  
> -#include <libfdt_env.h>
> -#include <fdt.h>
> +#include "libfdt_env.h"
> +#include "fdt.h"

Until this is resolved with upstream DTC, what about adding dummy
libfdt.h, libfdt_env.h and fdt.h to include/linux? That would get this
out of the blocker path for merging this code.

g.

Re: [PATCH] dtc: Use quotes to include header files

[Rob Herring]

On Thu, Jan 29, 2015 at 9:56 AM, Grant Likely <grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
> On Tue, 16 Dec 2014 15:13:24 +1300
> , Chris Packham <chris.packham-6g8wRflRTwXFdCa3tKVlE6U/zSkkHjvu@public.gmane.org>
>  wrote:
>> Currently in arch and driver code that needs early access to the
>> flattened device tree it is necessary to add specific CFLAGS so that
>> when scripts/dtc/libfdt/libfdt.h is included the C preprocessor is able
>> to locate the libfdt versions of libfdt_env.h and fdt.h without
>> generating an error.

[...]

>> diff --git a/scripts/dtc/libfdt/libfdt.h b/scripts/dtc/libfdt/libfdt.h
>> index 73f4975..ea1ddcd 100644
>> --- a/scripts/dtc/libfdt/libfdt.h
>> +++ b/scripts/dtc/libfdt/libfdt.h
>> @@ -51,8 +51,8 @@
>>   *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
>>   */
>>
>> -#include <libfdt_env.h>
>> -#include <fdt.h>
>> +#include "libfdt_env.h"
>> +#include "fdt.h"
>
> Until this is resolved with upstream DTC, what about adding dummy
> libfdt.h, libfdt_env.h and fdt.h to include/linux? That would get this
> out of the blocker path for merging this code.

2 of those already exist. Is it only a matter of adding fdt.h or is
there more to it?

This could also be carried as part of the import script to fix up.

Rob
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Re: [PATCH] dtc: Use quotes to include header files

[Chris Packham]

On Thu, 29 Jan 2015, Grant Likely wrote:

> On Tue, 16 Dec 2014 15:13:24 +1300
> , Chris Packham <chris.packham-6g8wRflRTwXFdCa3tKVlE6U/zSkkHjvu@public.gmane.org>
> wrote:
>> Currently in arch and driver code that needs early access to the
>> flattened device tree it is necessary to add specific CFLAGS so that
>> when scripts/dtc/libfdt/libfdt.h is included the C preprocessor is able
>> to locate the libfdt versions of libfdt_env.h and fdt.h without
>> generating an error.
>>
>> We already provide an alternative linux-specific
>> version of libfdt_env.h and directly include scripts/dtc/libfdt/fdt.h
>> so the inclusion by scripts/dtc/libfdt/libfdt.h is a no-op thanks to the
>> inclusion guards.
>>
>> By using quotes in scripts/dtc/libfdt/libfdt.h it picks up fdt.h and
>> libfdt_env.h from the source directory without needing to add CFLAGS for
>> the sources that happen to include linux/libfdt.h.
>>
>> Signed-off-by: Chris Packham <chris.packham-6g8wRflRTwXFdCa3tKVlE6U/zSkkHjvu@public.gmane.org>
>> ---
>> Hi,
>>
>> This probably should come via git://git.jdl.com/software/dtc.git however
>> this appears to be inaccessible at the moment. Is this still the
>> canonical source for the device tree compiler and libfdt or has it been
>> moved? How much deviation from the canonical source are we prepared to
>> live with in the kernel?
>>
>> This came up on the arm-LKML[1]. Basically in the name of backwards
>> compatibility I need to add a .dt_fixup to add some required nodes to
>> the flattened device tree prior to the tree being un-flattened and
>> processed. This is a trick powerpc makes use of fairly extensively and
>> there are a few other instances of this.
>>
>> For the files that include linux/libfdt.h we currently also have to
>> specify additional CFLAGS to satisfy the CPP.
>>
>>   $ git grep '<linux/libfdt.h>'
>>   arch/mips/cavium-octeon/octeon-platform.c:#include <linux/libfdt.h>
>>   arch/mips/cavium-octeon/setup.c:#include <linux/libfdt.h>
>>   arch/mips/mti-sead3/sead3-setup.c:#include <linux/libfdt.h>
>>   arch/powerpc/kernel/prom.c:#include <linux/libfdt.h>
>>   drivers/firmware/efi/libstub/fdt.c:#include <linux/libfdt.h>
>>   drivers/of/fdt.c:#include <linux/libfdt.h>
>>   drivers/of/fdt_address.c:#include <linux/libfdt.h>
>>
>>   $ git grep -e '-I.*dtc/libfdt'
>>   arch/mips/cavium-octeon/Makefile:CFLAGS_octeon-platform.o = -I$(src)/../../../scripts/dtc/libfdt
>>   arch/mips/cavium-octeon/Makefile:CFLAGS_setup.o = -I$(src)/../../../scripts/dtc/libfdt
>>   arch/mips/mti-sead3/Makefile:CFLAGS_sead3-setup.o = -I$(src)/../../../scripts/dtc/libfdt
>>   arch/powerpc/kernel/Makefile:CFLAGS_prom.o              = -I$(src)/../../../scripts/dtc/libfdt
>>   drivers/firmware/efi/libstub/Makefile:CFLAGS_fdt.o += -I$(srctree)/scripts/dtc/libfdt/
>>   drivers/of/Makefile:CFLAGS_fdt.o = -I$(src)/../../scripts/dtc/libfdt
>>   drivers/of/Makefile:CFLAGS_fdt_address.o = -I$(src)/../../scripts/dtc/libfdt
>>   lib/Makefile:   $(eval CFLAGS_$(file) = -I$(src)/../scripts/dtc/libfdt))
>>
>> Simply by switching to using quotes we can avoid having this extra step.
>>
>> Assuming that this patch is acceptable a follow on clean up would be to
>> remove the instances of CFLAGS_... listed above.
>>
>> Regards,
>> Chris
>> --
>> [1] - http://lists.infradead.org/pipermail/linux-arm-kernel/2014-December/310840.html
>>
>>  scripts/dtc/libfdt/libfdt.h | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/scripts/dtc/libfdt/libfdt.h b/scripts/dtc/libfdt/libfdt.h
>> index 73f4975..ea1ddcd 100644
>> --- a/scripts/dtc/libfdt/libfdt.h
>> +++ b/scripts/dtc/libfdt/libfdt.h
>> @@ -51,8 +51,8 @@
>>   *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
>>   */
>>
>> -#include <libfdt_env.h>
>> -#include <fdt.h>
>> +#include "libfdt_env.h"
>> +#include "fdt.h"
>
> Until this is resolved with upstream DTC, what about adding dummy
> libfdt.h, libfdt_env.h and fdt.h to include/linux? That would get this
> out of the blocker path for merging this code.
>
> g.
>

I'm traveling right now but I could work up an example patch next week.

>From the other discussions I think there are arguments in favor of keeping 
the angle brackets for the userspace libfdt usage. Any change in the 
kernel either adding dummy files in the system include path or performing 
a subsititution in an import script would probably be permanent.
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