>> 0xbe000000 is in the uncached, unmapped (no TLB) section called KSEG1.
>>  In KSEG1 the physical address is the same as the virtual address with
>> the top 3 bits forced to 0.  The MIPS boot address is in KSEG1 @
>> 0xbfc00000
> Interesting... That means we *can* in fact reprogram the flash whenever the
> bootloader is really, really ruined ?
> I have a box that have this problem: the flash is fully empty, and I can't
> detect it at all.
> I'll try with the above address...

I started to investigate this with an BCM4712 based system (Siemens
SE505) as well. In the meantime I can read the flash area and the
detectflash works as well. Haven't tried flashing itself yet, however.

Commands given:
cable arm-usb-ocd driver=ftdi-mpsse
frequency 1000000

[messages about detecting the bcm4712 and loading the respective file]

register        EJIMPCODE       32
register        EJADDRESS       32
register        EJDATA          32
register        EJCONTROL       32
register        EJALL           96
register        EJFASTDATA      33

instruction     EJTAG_IMPCODE   00000011   EJIMPCODE
instruction     EJTAG_ADDRESS   00001000   EJADDRESS
instruction     EJTAG_DATA      00001001   EJDATA
instruction     EJTAG_CONTROL   00001010   EJCONTROL
instruction     EJTAG_ALL       00001011   EJALL
instruction     EJTAGBOOT       00001100   BR
instruction     NORMALBOOT      00001101   BR
instruction     EJTAG_FASTDATA  00001110   EJFASTDATA

initbus ejtag

detectflash 0x3fc00000
-> base address of flash in 16 bit bus area

readmem 0x3fc00000 0x100 cfe.bin
-> reads first 256 bytes of CFE, compare with reference data ok

readmem 0x3fff8000 0x400 nvram.bin
-> reads the first 1k of NVRAM, reasonable data

If the register and instructions definitions are ok, I'd add them to the
official bcm4712 description file in urjtag trunk. What is your
impression here?

I wasn't able to get anything useful from the ejtag_dma driver yet...


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