Dear Peter Chen,
In message 1250571462.6548.21.camel@nchen-desktop you wrote:
The "jump table provided by U-Boot exactly for this purpose" is the list of functions exported through the "include/_exports.h" header file.
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If you set up your own list of function pointers (in addition or instead of the jump table provided by the "include/_exports.h" header), then this is a form of linking against the U-Boot code, and your application must be released under GPL.
I am sorry, I can't understand your meaning. For example, at
I'm close to give up. I try to as explicit as possible, and I see no room for interpretation left, yet you still try to argument.
"include/_exports.h" there is an EXPORT_FUNC(printf), do the standalone application must under GPL if it uses printf?
No. As explained several times before, the "jump table [is] provided by U-Boot exactly for this purpose", with "this purpose" being to allow for closed source, proprietary code.
printf() gets exported through the jump table interface, so this is OK to use in proprietary code.
Then, what does "include/_exports.h" use?
It uses a list of functions (resp. function pointers) we consider OK to be used in closed source applications.
In your COPYING, it writes: NOTE! This copyright does *not* cover the so-called "standalone" applications that use U-Boot services by means of the jump table provided by U-Boot exactly for this purpose - this is merely considered normal use of U-Boot, and does *not* fall under the heading of "derived work".
Indeed. And I explained this several times before.
Is it free to license at below situation: The function list which is defined at u-boot/board/myboard/myboard.c, and all functions in this list only uses functions at include/_exports.h and some of user-defined functions.
Your description is really vague; it would be easier if you could give specific code examples or such. If "some of user-defined functions" refers to code that is covered by the GPL, then your application must be released under GPL, too.
My code like belows:
typedef void (*pfn_t) (void); pfn_t sc_gps_pfn[] = { LoadToMemory, SaveData, RFPowerCtrl, MiscConfig, RegisterDspInterruptHandler, GetPowerStatus, IsUserResume, DebugOutput, ReturnToBootLoader };
OK, so you are setting up a table of your own functions. You need this table only if you link the code containing these functions with the U-Boot binary - and you do so most probably because the code calls into other U-Boot provided functions.
We want to open this code, but want to close the code which use this function list in binary pattern.
You probably have no choice here. If your code that provides the list of functions above is linked with U-Boot, you *must* release it under GPL. No matter if you want or not - if you release your code at all, it is GPLed.
And your list of functions above thus accesses GPLed code which is NOT part of include/_exports.h. So the GPL exception does NOT apply to any code that references functions from this list, i. e. your standalone application must be released under GPL, too.
What you implement is some form of static linking.
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The standalone application is compiled by armcc, and this bin file is shared by WinCE and Linux bootloader. The standalone application uses bootloader functions by address not by name.
That does not matter. Accessing a function by address still means you are linking against the code (in a stupid way, btw). Your standalone application has to be released under GPL.
Best regards,
Wolfgang Denk