[U-Boot] coding style question: when to use __weak function attributes?

[U-Boot] coding style question: when to use __weak function attributes?

[Robert P. J. Day]

  pardon yet another question on coding style and pedantry, but i'm
curious about the following. i'm crawling through the code in
common/image-fdt.c, specifically in image_setup_libfdt(), and first i
see the following:

  __weak int arch_fixup_fdt(void *blob)
  {
          return 0;
  }

  ... snip ...

        if (arch_fixup_fdt(blob) < 0) {
                printf("ERROR: arch-specific fdt fixup failed\n");
                goto err;
        }

which is perfectly understandable -- use the weak function attribute,
and let each architecture decide if it wants to override that. same
thing here in that same file:

  __weak int ft_verify_fdt(void *fdt)
  {
          return 1;
  }

  ... snip ...

        if (!ft_verify_fdt(blob))
                goto err;

which then makes me wonder why the same approach wasn't used for these
routines as well:

        if (IMAGE_OF_BOARD_SETUP) {
                fdt_ret = ft_board_setup(blob, gd->bd);
                if (fdt_ret) {
                        printf("ERROR: board-specific fdt fixup failed: %s\n",
                               fdt_strerror(fdt_ret));
                        goto err;
                }
        }
        if (IMAGE_OF_SYSTEM_SETUP) {
                fdt_ret = ft_system_setup(blob, gd->bd);
                if (fdt_ret) {
                        printf("ERROR: system-specific fdt fixup failed: %s\n",
                               fdt_strerror(fdt_ret));
                        goto err;
                }
        }

couldn't ft_board_setup() and ft_system_setup() have been defined the
same way? or is there something different about those two routines
that wouldn't allow the weak function attribute and do away with all
the OF_BOARD_SETUP and OF_SYSTEM_SETUP usage?

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
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