[U-Boot] __FILE__ usage and and SPL limits for SRAM

[Masahiro Yamada]

2017-03-28 20:47 GMT+09:00 Felipe Balbi <felipe.balbi at linux.intel.com>:
>
> Hi,
>
> Nishanth Menon <nm at ti.com> writes:
>> Hi Masahiro-san,
>>
>> On Tue, Mar 28, 2017 at 1:29 AM, Masahiro Yamada
>> <yamada.masahiro at socionext.com> wrote:
>> [...]
>>>
>>> When O= is given, the build system runs in the object tree,
>>> not in the source tree.
>>> (This is the same as Linux.)
>>>
>>> If you see the top Makefile:
>>>
>>> ifeq ($(KBUILD_SRC),)
>>>         # building in the source tree
>>>         srctree := .
>>> else
>>>         ifeq ($(KBUILD_SRC)/,$(dir $(CURDIR)))
>>>                 # building in a subdirectory of the source tree
>>>                 srctree := ..
>>>         else
>>>                 srctree := $(KBUILD_SRC)
>>>         endif
>>> endif
>>>
>>>
>>>
>>>
>>> If O=  points to a sub-directory of the source tree,
>>> the relative path "srctree := .." is used.
>>>
>>> Otherwise, the absolute path srctree := $(KBUILD_SRC) is used.
>>> In your case, "O=../b" means the source tree and the obj tree
>>> are siblings.  So, absolute path.
>>
>> I did simplify this a bit with O=../b to highlight exactly what you
>> mentioned above. in our case, the O=path points to a completely
>> different directory path.
>>
>>> If you want to see a short relative path for __FILE__,
>>> I'd recommend to use a sub-directory for O=.
>>>
>>> For example, your source tree is located at
>>> ~/aaaaaaaaa/bbbbbbb/cccccccc/u-boot,
>>> create a directory  ~/aaaaaaaaa/bbbbbbb/cccccccc/u-boot/foo,
>>> then give  O=foo
>>
>> Typical product build such as OE recipes used (in our case) does not
>> build into the source folder, instead, all binary builds are pointed
>> to either a temporary location or a package build location. So, while
>> O=source_path/build would aliviate the problem, it still does'nt
>> really solve the root of the issue.
>
> have you tried using __BASE_FILE__ instead of __FILE__? You could also
> redefine __FILE__ or __BASE_FILE__ while building SPL.


__BASE_FILE__ and __FILE__ are the same
in the sense that both of them points to the
path to the file, right?
In Nishanth's case, both are abs path.


We see difference when they are used in a header file.

For example, in foo.h

static inline void foo(void)
{
        printf("this header file is %s\n", __FILE__);
        printf("this header is included from %s\n", __BASE_FILE__);
}


__FILE__ is a path to foo.h

On the other hand, __BASE_FILE__ is a path
to a C file that includes foo.h




-- 
Best Regards
Masahiro Yamada