Wolfgang Denk wd@denx.de wrote on 2011/01/09 21:44:08:
Dear Joakim Tjernlund,
In message 1292838435-14958-1-git-send-email-Joakim.Tjernlund@transmode.se you wrote:
Remove dependencies on link address. Use GOT and add an new function to calculate the actual address.
Signed-off-by: Joakim Tjernlund Joakim.Tjernlund@transmode.se
arch/powerpc/cpu/mpc83xx/start.S | 35 +++++++++++++++++++++++++++-------- 1 files changed, 27 insertions(+), 8 deletions(-)
It seems this code introduces some subtle changes.
- lis r4, (CONFIG_SYS_MONITOR_BASE)@h
- ori r4, r4, (CONFIG_SYS_MONITOR_BASE)@l
- addi r5, r4, in_flash - _start + EXC_OFF_SYS_RESET
- mtlr r5
The original code references CONFIG_SYS_MONITOR_BASE.
- bl add_flash_base
...
+add_flash_base:
- /* Check if already inside flash address space. */
- /* if so, do not add CONFIG_SYS_FLASH_BASE */
- lis r4, (CONFIG_SYS_FLASH_BASE)@h
- ori r4, r4, (CONFIG_SYS_FLASH_BASE)@l
- cmplw cr0, r3, r4
- ble cr0, 2f /* r3 < r4 ? */
- lis r6, (CONFIG_SYS_FLASH_BASE+(CONFIG_SYS_FLASH_SIZE*1024*1024-1))@h
- ori r6, r6, (CONFIG_SYS_FLASH_BASE+(CONFIG_SYS_FLASH_SIZE*1024*1024-1))@l
- cmplw cr0, r3, r6
- blelr cr0 /* r3 < r6 ? */
+2: add r3,r3,r4
- blr
But your new code does not reference CONFIG_SYS_MONITOR_BASE at all, but uses CONFIG_SYS_FLASH_BASE instead.
You can't assume a fixed address when doing PIC therefore the change.
On which boards has this been tested?
Only on our custom 83xx boards.