On 9/20/07, Steve Williams steve@parsonscroft.plus.com wrote:
Just one point here my u-boot for our custom MPC8548 board starts at 0xfff80000 not 0xff800000. Unless you changed the linker map won't this mean that the code that is supposed to live at the reset vector is not actually there?
Try looking right at the top of flash (the last 16 bytes) for the jump.
Maybe I have missed something obvious here but I just thought I point it out
Regards
Steve Williams
Hi Steve. What board are you referring to - is it open sourced ? I can't get any signs of life yet so I tried 0xfff80000 (0xfffff01c is _start_e500 in start.S) :
ATUM4>mdh 0xfff80000 0_fff80000 : 2705 1956 552d 426f 6f74 2031 2e33 2e30 '..VU-Boot 1.3.0
ATUM4>bi 0xfffff01c Breakpoint identification is 0 ATUM4>go 0xfff80000 ATUM4>halt Target CPU : MPC85xx (e500v2 rev.2) Target state : halted Debug entry cause : COP halt Current PC : 0xf0000000 Current CR : 0x00000000 Current MSR : 0x00000200 Current LR : 0x00000000 Current CCSRBAR : 0x0_e0000000
In a nutshell I'm trying to figure out what the pc is doing and why - I can't hit breakpoints nor see any signs of code running. The docs do say:
4.4.3.3 Boot ROM Location The MPC8548E defines the default boot ROM address range to be 8 Mbytes at address 0x0_FF80_0000 to 0x0_FFFF_FFFF. However, which peripheral interface handles these boot ROM accesses can be selected at power on.
As I said I could be reading this wrong. The 8548 cds code in 1.3 rc1 has:
#define CFG_BOOT_BLOCK 0xff000000 /* boot TLB block */ #define CFG_FLASH_BASE CFG_BOOT_BLOCK /* start of FLASH 16M */ #define CFG_FLASH_BANKS_LIST {0xff800000, CFG_FLASH_BASE}
Am I reading all this to mean I should load uboot to 0xff800000 - is that wrong ?
Incidently, I'm going thru the docs trying to find exceptions in the registers - these aren't changing for me:
ATUM4>rd spefscr spefscr : 0x00000000 0 ATUM4>rd dear dear : 0x00000000 0 ATUM4>rd esr esr : 0x00000000 0
In fact, I'm seeing the behavior running u-boot and with the flash erased via typing "go uboot address" - I can't see any difference in any registers.
I wrote an email to freescale tech support to see if there is some register I can see to find the error or some other type of help they can offer.
Thanks all! Robert