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

[Peter Howard]

On Wed, 2014-12-03 at 06:38 -0700, Simon Glass wrote:
> 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.

I may be missing something, but the GDT appears to be x86-specific
whereas I'm building for ARMv5.
-- 
Peter Howard <pjh at northern-ridge.com.au>