[U-Boot] BUG: bootz/bootm command mandates a fdt blob

[Hans de Goede]

Hi Suriyan,

On 11/20/2014 04:16 PM, Suriyan Ramasami wrote:
> Hello Simon,
>      This mail is addressed to you as the FDT support was added by
> you. I am not sure who else to address it to.
> 
>       I find that if CONFIG_OF_LIBFDT is defined then the user is
> forced to provide a FDT blob. In most of the cases it makes sense.
> However, this removes the ability to boot older linux (non FDT).
>     For example, I was looking at the Hardkernel Odroid kernels for
> the U2/U3, and they are 3.8 based. Of course newer kernels 3.17 work.
> For users to use the same boot loader for 3.8 and for 3.17, they
> cannot use the mainline uboot.

I've hit the same problem myself recently, see the thread titled:

"Booting non devicetree enabled kernels using u-boot build with CONFIG_OF_LIBFDT"

>     I was wondering if teh third argument to bootz/bootm etc could
> also take the route of initrd (optional if - is specified) could be
> implemented.
> 
>    The fix seems to be trivial (or so I think), in file
> common/image-fdt.c, but wanted to know your comments on this. Also the
> command help (for bootz etc) states that if the 3rd argument is not
> passed, then the bd_info struct is passed, and I do not see it being
> passed in the code anywhere. In the absence of the third parameter, it
> just gives a "No fdt found" message.

Thanks for working on a fix, as discussed in the earlier thread, requiring
a third argument which is '-' will break old boot.scr files and the likes,
so a better fix is to:

1) Always try to find an ftd (to keep things like appended ftd-s working)
2) If not found see if there is a third argument, if there is, treat this
as a fatal error, abort the bootm (iow behave as before)
3) If there is not a third argument warn and continue as before.

If you could respin your patch to do this, then that would be great.

Regards,

Hans


> 
> diff --git a/common/image-fdt.c b/common/image-fdt.c
> index a39ae1b..e685700 100644
> --- a/common/image-fdt.c
> +++ b/common/image-fdt.c
> @@ -243,7 +243,10 @@ int boot_get_fdt(int flag, int argc, char * const argv[], u
> 
>         if (argc > 2)
>                 select = argv[2];
> -       if (select || genimg_has_config(images)) {
> +       if (select && strcmp(select, "-") ==  0) {
> +               debug("## Skipping fdt\n");
> +               return 0;
> +       } else if (select || genimg_has_config(images)) {
>  #if defined(CONFIG_FIT)
>                 if (select) {
>                         /*
> 
> Regards
> - Suriyan
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