Hello
The Reference Hardware/Software config: EP8260 M 1.3, 32Mb SDRAM, 8 Mb Flash Reset exception vector at FFF0 0100 WireTAP JTAG connected to my computer's parallel port Serial Terminal and HyperTerminal used for monitor/console.
Baud rate: 115200 u-boot 1.1.1 ELDK "Flash Programmer" in CodeWarrior on Windows used for burning u-boot.srec into the FLASH.
debug build of u-boot HRCW = 0x10400245
The Problem: On power-up, u-boot starts executing, displays a few messages, and stops. No command prompt. The last message printed is: "New Stack Pointer is: 0x1F3 6F48"
In the source code, that message appears just before the call to relocate_code(). relocate_code is implemented in assembly (in cpu/mpc8260/start.S).
Since I could not figure out how to debug/single-step through the code using WireTAP, I used printfs and debug()s for debugging. And since printfs are not possible in start.S, I used the on-board LEDs to figure out that the code halts _at_ the branch to in_ram
That is where I am stuck. Where does the execution control branch to? How do I figure out where the code is going? I know it does not reach in_ram because the first statements there is my code to glow the LEDs.
How do I debug u-boot? Should I use CodeWarrior or gdb? I have never used either of them before.
If I have to use CodeWarrior, how do I go about it? Do I have to import the u-boot source tree into the CodeWarrior IDE? Do I have to compile u-boot using CW? If yes, then that's another problem altogether.
If I have to use gdb, what commands do I give? I have tried both 'gdb' and 'ppc_82xx-gdb'.
(gdb) target remote /dev/lp0 gives errors saying set_tty_state failed: Invalid argument
(gdb) target jtag /dev/lp0 and (gdb) target jtag jtag://localhost:9999 give errors saying Undefined target command: "jtag /dev/lp0". Try "help target".
Observations / attempts: u-boot 1.1.1 was meant for EP8260 rev. 1.1 (64Mb RAM, 16 Mb Flash)
I made the changes necessary for rev. 1.3 in board/ep8260/ep8260.h and include/configs/ep8260.h
Kept Flash as 16 Mb (If I change it to 8, no messages appear on the screen) Changed the 60x RAM size to 32 Mb Local bus SDRAM was already 0, no change required.
Debug build gives messages: Top of usable RAM found at 0x0200 0000 And other values till it prints: New Stack Pointer at: 01F3 6F48
Any help, pointers, reference, tutorials, etc. would be a great help. I need some help desperately.
Warm regards, Nishant