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<p class=MsoNormal>Hello<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span lang=EN-US>When I started the implementation of my new
hardware platform AT91SAM9263, I wondered about the distinction of these to
symbols. The naming suggest that <i>platform</i> is the name by which the
target is referenced in the command line <b>tools/build.py MACHINE=<platform>
…</b> while <i>platform_dir</i> is the location where the
platform-specific files should reside. However, the observation was that in given
examples the values were the same.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Since I foresee that we will have another
ATMEL platform which is quite similar to the current one, I plan to draw it
from the same platform directory. The few differences can well be controlled by
a preprocessor directive. For this purpose I could either create my own one by
adding it to <i>cpp_defines,</i> or make use of <i>MACHINE_<platform></i>
which is automatically created.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>However, an attempt to change the name of
the platform directory and adapt <i>platform_dir</i> accordingly made the build
fail. It turned out that the value of <i>platform_dir </i>is nowhere considered
in the build scripts, effectively rendering it useless. The main reason for
this behaviour is found in <i>pistachio/SConscript</i> around line 76:<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:35.4pt'><span lang=EN-US
style='color:#1F497D'>platform = env.machine.platform<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:35.4pt'><span lang=EN-US
style='color:#1F497D'>platform_dir = "#" +
os.path.join("platform", src_platform, args["package"])<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>These two statements establish the platform
path from the value of the symbol <i>platform</i> while the value of <i>platform_dir</i>
is ignored. Since changing the first line to ‘platform =
env.machine.platform_dir’ would not work, because ‘platform’
is used several times further on in <i>pistachio/SConscript</i> where it must
deliver the platform name and not the directory, I made the following change:<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:35.4pt'><span lang=EN-US
style='color:#1F497D'>platform = env.machine.platform<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:35.4pt'><span lang=EN-US
style='color:#1F497D'># FK: make the platform file location distinct from the
platform name<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:35.4pt'><span style='color:#1F497D'>src_platform
= env.machine.platform_dir<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:35.4pt'><span lang=EN-US
style='color:#1F497D'>platform_dir = "#" + os.path.join("platform",
src_platform, args["package"])<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>This works as expected, and I would
appreciate is this could go into the next version of OKL4.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>There is another concept to support
multiple platforms from the same sources: that is introducing subplatforms.
However, this approach requires their introduction into the generic build
scripts of PISTACHIO and IGUANA (as can be seen with the s3c2410 platform), that
is why I dismissed this solution.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Regards<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Frank<o:p></o:p></span></p>
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