On 07/08/2014 10:05 AM, Helmut Raiger wrote:
I meant, that the SPL is now doing the RAM init and copying of the SPL
code
correctly. RAM is working, the SPL code is at 0x87dc0000 after that
(CRCed it via JTAG).
I could not track it further (I have very limited development time
right now ... repeating myself).
After all I need to debug further. If someone could test the current
state on the
mx31pdk, this still would be great. Just to rule out any other board
specific issues.
Helmut
Ok, I've got some new input and I have no clue what's going on.
1) I fixed the first branch to reset (uses b reset instead of ldr pc,
_reset)
2) The startup does:
b reset
...
reset:
- set the cpu to SVC32 mode
- bl cpu_init_crit (cache and MMU stuff, calls low_level_init)
- bl _main
low_level_init:
unlike in mx31pdk this only does:
ldr r0, =ARM_PPMRR /* start from AIPS 2GB region */
mcr p15, 0, r0, c15, c2, 4
mov pc, lr
_main:
- set up stack pointer to internal SRAM
- bl board_init_f
As I can't break right after reset with peedi, I do:
- reset stop
- set pc 0xb8000000
- go -> system never returns
next:
reset stop
- set pc 0xb8000000
- break add hard 0xb80000c8 // set hardware breakpoint to the
'bl board_init_f' instruction
- go
... it stops at the breakpoint
- go
... I'm at the u-boot command prompt
If I set the breakpoint somewhere after the bl board_init_f it fails, if
I break a few instructions
early and go from there it also fails. Tracking down the location
in-between I end up at:
at the end of cpu_init_crit():
mov ip, lr /* persevere link reg across call */
bl lowlevel_init /* go setup pll,mux,memory */
-> mov lr, ip /* restore link */
mov pc, lr /* back to my caller */
That is, if I set the breakpoint to mov lr, ip it works, if I set it one
instruction later it ends working.
Could be struggling with the debugger here, as the SPL probably ran a
few instruction before it
was stopped. Might this be a cache issue? But it is invalidated in
cpu_init_crit() anyway ...
Feeling a little dumbstruck right now ...
Sorry for the mess, but it's hard to describe.
Any ideas?
Helmut
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