[U-Boot] a couple questions about CONFIG_SYS_LONGHELP
Albert ARIBAUD
albert.u.boot at aribaud.net
Sat Jan 26 12:45:42 CET 2013
Hi Robert,
On Sat, 26 Jan 2013 06:38:51 -0500 (EST), "Robert P. J. Day"
<rpjday at crashcourse.ca> wrote:
>
> first, is there any need for so many header files to define the
> macro CONFIG_SYS_LONGHELP individually? a quick count of how many
> u-boot source files do just that:
>
> $ grep -r "define.*CONFIG_SYS_LONGHELP" * | wc -l
> 479
> $
>
> is it really necessary for almost 500 source files to each define that
> macro?
Yes, is is, because each target should decide individually if they want
to embed the long help, which costs space and time, two valuable
resources in embedded development.
> and second, i'm not sure how to read this out of cmd_pci.c:
>
> ===== start
>
> #ifdef CONFIG_SYS_LONGHELP
> static char pci_help_text[] =
> "[bus] [long]\n"
> " - short or long list of PCI devices on bus 'bus'\n"
> #ifdef CONFIG_CMD_PCI_ENUM
> "pci enum\n"
> " - re-enumerate PCI buses\n"
> #endif
> "pci header b.d.f\n"
> " - show header of PCI device 'bus.device.function'\n"
> "pci display[.b, .w, .l] b.d.f [address] [# of objects]\n"
> " - display PCI configuration space (CFG)\n"
> "pci next[.b, .w, .l] b.d.f address\n"
> " - modify, read and keep CFG address\n"
> "pci modify[.b, .w, .l] b.d.f address\n"
> " - modify, auto increment CFG address\n"
> "pci write[.b, .w, .l] b.d.f address value\n"
> " - write to CFG address";
> #endif
>
> U_BOOT_CMD(
> pci, 5, 1, do_pci,
> "list and access PCI Configuration Space", pci_help_text
> );
>
> ===== end
>
> note how, if CONFIG_SYS_LONGHELP is defined, the symbol
> "pci_help_text" is created as the text, but its *usage* just below in
> the U_BOOT_CMD macro is *outside* of that preprocessor check. how
> would that work if CONFIG_SYS_LONGHELP is undefined? not at my dev
> host right this minute so i can't test, but it just looks ... weird.
Probably would not work. Submit a fix. :)
> rday
Amicalement,
--
Albert.
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