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

[Hans de Goede]

Hi,

On 11/20/2014 08:41 PM, Suriyan Ramasami wrote:
> Hello Simon,
> 
> On Nov 20, 2014 8:38 AM, "Simon Glass" <sjg at chromium.org> wrote:
>>
>> Hi,
>>
>> On 20 November 2014 16:04, Hans de Goede <hdegoede at redhat.com> wrote:
>>> 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.
>>
>> Just to be clear, I didn't add FDT support, this predates my
>> involvement in U-Boot. I added CONFIG_OF_CONTROL etc. though. Han's
>> solution sounds good to me.
>>
> 
> Sorry about that. In no way was I accusing you :-) I stand corrected though.
> 
>>>>
>>>>       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.
>>>
> 
> Hello Hans/Simon,
>    I have been tracing the code paths and see that function
> bootm_find_fdt() is the final fdt prep function.
>    To retain all its previous functionality, but introducing a warning
> condition if no third argument is present, but go ahead and boot without
> fdt should keep the peace.
>     The easiest way to achieve this is: (takes care of 2 and 3 above)
> 
> diff --git a/common/image-fdt.c b/common/image-fdt.c
> index a39ae1b..1a02166 100644
> --- a/common/image-fdt.c
> +++ b/common/image-fdt.c
> @@ -430,6 +430,10 @@ int boot_get_fdt(int flag, int argc, char * const
> argv[], u
>  error:
>         *of_flat_tree = NULL;
>         *of_size = 0;
> +       if (argc <= 2) {
> +               debug("Continuing to boot without FDT\n");
> +               return 0;
> +       }
>         return 1;
>  }
> 
> For case 1, is this already handled in the code?

Yes it is, so your above patch should do the trick nicely, thanks for working on
this.

Can you re-send as a proper patch, with commit message, rather then inline in
a mail ? (Please use git send-email if possible).

Regards,

Hans