[U-Boot] Problem converting da850evm to generic board and use libfdt

[Peter Howard]

I'm trying to make two changes to building u-boot for the da850evm.
      * Use the generic board code to get rid of the warning, and
      * Enable libfdt to allow booting of linux with a standalone dtb
        image.

The first part appears to be simple.  Just adding 

        #define CONFIG_SYS_GENERIC_BOARD

in include/configs/da850evm.h works with no obvious side-effects.

However, adding

        #define CONFIG_OF_LIBFDT

is a different story.  It appears to introduce memory corruption when
loading the environment.  On first boot it gives the "bad CRC!" warning
and uses the default environment.  If you *don't* save the environment
you can boot fine (including manual editing of the environment). However
if you save the environment via saveenv bad things happen on the next
boot.  An example log:

U-Boot SPL 2015.01-rc1 (Nov 27 2014 - 14:30:26)                                 
                                                                                
                                                                                
U-Boot 2015.01-rc1 (Nov 27 2014 - 14:30:26)                                     
                                                                                
I2C:   ready                                                                    
DRAM:  64 MiB                                                                   
WARNING: Caches not enabled                                                     
MMC:   davinci: 0                                                               
SF: Detected M25P64 with page size 256 Bytes, erase size 64 KiB, total 8 MiB    
In:    serial                                                                   
Out:   serial                                                                   
Err:   serial                                                                   
SF: Detected M25P64 with page size 256 Bytes, erase size 64 KiB, total 8 MiB    
Warning: Invalid MAC address read from SPI flash                                
Net:   DaVinci-EMAC                                                             
Error: DaVinci-EMAC address not set.                                            
                                                                                
U-Boot > help                                                                   
data abort                                                                      
pc : [<c108ffd8>]          lr : [<c10900b4>]                                    
sp : c3e5f838  ip : 00000000     fp : c3e5fda4                                  
r10: c10b1f28  r9 : c3e5ff08     r8 : 0000000e                                  
r7 : c10b22c4  r6 : c10aa2a0     r5 : 00000000  r4 : 0000001b                   
r3 : c10b8f70  r2 : 00000001     r1 : c3e5f840  r0 : ffffffff                   
Flags: Nzcv  IRQs off  FIQs off  Mode SVC_32                                    
Resetting CPU ...     

If I rebuild  with CONFIG_OF_LIBFDT removed again from da850evm.h the
problem disappears.  And you can see that the saveenv worked (i.e. the
environment is what was saved before the reboot and data abort).

I've traced the problem as far as the inline version of console_puts()
in common/console.c.  The table dispatch there and the fact that the
problem appears only when you load the environment makes me think it's
memory corruption.

Note: if you do *not* specify CONFIG_SYS_GENERIC_BOARD you still get the
data abort, however it takes a bit more effort to trigger (like actually
looking at the environment :-)  )

(Note: This is building against the u-boot-2015.01-rc1 tree)

Suggestions?
                                         
-- 
Peter Howard <pjh at northern-ridge.com.au>