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

[Simon Glass]

Hi Peter,

On 2 December 2014 at 14:59, Peter Howard <pjh at northern-ridge.com.au> wrote:
>
> 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?

In case it helps, I got the same symptom (help crashes) and it was due
to BSS not being cleared. Stefan (on cc) found this problem - he said
something to do with GDT calculation or handling. However it is just a
guess and probably has nothing to do with your issue.

Regards,
Simon