[U-Boot-Users] [PATCH v2] [new uImage] ppc: Re-order ramdisk/fdt handling sequence

[Marian Balakowicz <m8@semihalf.com>]

Kumar Gala wrote:
> On Feb 18, 2008, at 1:46 PM, Jerry Van Baren wrote:
> 
>> Kumar Gala wrote:
>>> On Feb 18, 2008, at 1:15 PM, Jerry Van Baren wrote:
>>>> Kumar Gala wrote:
>>>>> On Feb 18, 2008, at 11:51 AM, Jerry Van Baren wrote:
>>>>>> Kumar Gala wrote:
>> [[[[snip]]]]
>>
>>>> The patch is creating dummy initrd entries in the reserved map and  
>>>> in /chosen, only to work hard to delete and re-create the reserved  
>>>> map entries and rewrite the /chosen entries.
>>>>
>>>> My counter-proposal is to not bother with dummy values.  Simply  
>>>> pass in 0,0 which will prevent the creation of the initrd entries  
>>>> by fdt_chosen().  By not creating dummy entries, you can simply  
>>>> create the proper entries once you know what the the correct  
>>>> values are, rather than the more complicated rsvmap search &  
>>>> delete + rsvmap creation + /chosen modifications.
>>> Ahh, the reason I wanted them created was to ensure we have enough  
>>> size for them up front rather than figuring that out later.  By  
>>> creating them and replacing them I will not being changing the size  
>>> at all.
>>> - k
>> OK, I see.
>>
>> Currently this isn't an issue because our blob has a fixed size that  
>> has free space inside it, so creating the rsvmap and /chosen entries  
>> eat at the internal free space and don't change the total blob size.
>>
>> People are advocating dynamically increasing the blob size, which  
>> simplifies things for blob generation (don't have to guess how big  
>> to make the blob when running the dtc to create it), but that would  
>> cause problems with my counter-proposal.
> 
> And the whole point of my patch was to enable the ability to  
> dynamically grow the blob before we do anything w/the ramdisk.

But we don't really grow the blob, we are just allocating the space for
the initrd properties - *if* the blob already has enough free space. If
the blob does not have enough free space we'll hit the bottom anyway,
whether in fdt_chosen() or ft_board_setup(), so it seem that it doesn't
matter whether we pre-allocate space for initrd or not. Or am I missing
something?

I was rather thinking of increasing the total blob size when relocating
it. Currently relocation happens only when the blob is not within
BOOTMAPSZ region, so we would need to always relocate the blob and
figure out the size delta: (1) get it from env variable, if set (2) or
use some default delta. What do you think?

Cheers,
m.