[U-Boot] 85xx: MPC8536DS board does not build

[Jerry Van Baren <gerald.vanbaren@ge.com>]

Kumar Gala wrote:
> On Aug 10, 2009, at 1:59 PM, Zang Roy-R61911 wrote:
> 
>>
>>> -----Original Message-----
>>> From: Kumar Gala [mailto:galak at kernel.crashing.org]
>>> Sent: Monday, August 10, 2009 13:41 PM
>>> To: Wolfgang Denk
>>> Cc: U-Boot-Users ML; Zang Roy-R61911
>>> Subject: Re: 85xx: MPC8536DS board does not build
>>>
>>>
>>> On Aug 10, 2009, at 1:22 PM, Wolfgang Denk wrote:
>>>
>>>> Dear Kumar Gala,
>>>>
>>>> In message <0EB7516A-2F14-42F7-
>>>> A6ED-555ADFAB3105 at kernel.crashing.org> you wrote:
>>>>>> Allocate more space for U-Boot?
>>>>> I might turn of BEDBUG as its never been properly enabled on
>>>>> e500/85xx
>>>>> platforms.
>>>> Is there any problem with the bigger image which I don't understand
>>>> yet? Normally we just move down the TEXT_BASE by a sector,
>>> and that's
>>>> it.
>>> Not specifically, its just that ever 85xx image to date has been
>>> 512k.  I'm just trying to avoid this being the first one that
>>> changes
>>> that historic fact.  Especially since compilers like gcc-4.3 seem to
>>> be able to fit the size in 512k.
>> We may have more requirements to support graphic in u-boot.
>> Sooner and later, the size will exceed 512K. Should we have some plan
>> for this?
> 
> So if we are going to increase the limit from 512k do we go to 768k or  
> 1M?  (Sector size on the board appears to 128k)
> 
> I would also like to know how big the flashes are on some of the other  
> 85xx boards that u-boot supports.
> 
> - k

Hi Kumar, Roy,

512K is pretty big for u-boot (not unheard of, but still...).  Is it 
really 512K or is it using a full page to hold the boot page (top 4K of 
memory) and one page for the env (unavoidable):

+-------------------------------------------------------- 0x1_0000_0000
| One sector dedicated for the power up page (only using 4K)
+-------------------------------------------------------- 0x0_F800_0000
| One sector dedicated for the env
+-------------------------------------------------------- 0x0_F000_0000
| Two sectors of u-boot
+----                                                     0x0_E800_0000
|
+-------------------------------------------------------- 0x0_E000_0000


If that is the case, you can gain a sector (less 4K) by rearranging your 
memory map:
+-------------------------------------------------------- 0x1_0000_0000
| One page (4K) of power up vector, the rest is u-boot
+----                                                     0x0_F800_0000
|
+----                                                     0x0_F000_0000
| Three sectors (less 4K) of u-boot
+-------------------------------------------------------- 0x0_E800_0000
| One sector dedicated for the env
+-------------------------------------------------------- 0x0_E000_0000

This also makes reprogramming u-boot nicer because your power up vector 
and u-boot itself are contiguous.

Best regards,
gvb