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Altera_Forum's avatar
Altera_Forum
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21 years ago

Hpw do I change the startup adr of an app

Hi

I tried writing about this before. Hope someone can help me.

I have a simple program. I want to change the startup adr of my program from 0x1000000(SDRAM base adr) to for an exsample 0x1100000. I have tried to define my own custom linker script in the system library.

Here below I have copied in the changes I made to the default linker script

-----------------------------------------------------------------------------------------------------

MEMORY

{

reset : ORIGIN = 0x00000000, LENGTH = 32

ext_flash : ORIGIN = 0x00000020, LENGTH = 8388576

ext_ram : ORIGIN = 0x00800000, LENGTH = 1048576

epcs_controller : ORIGIN = 0x00900000, LENGTH = 2048

sdram_UNUSED : ORIGIN = 0x01100000, LENGTH = 32

sdram : ORIGIN = 0x01100020, LENGTH = 15728640

}

/* Define symbols for each memory base-address */

__alt_mem_ext_flash = 0x00000000 ;

__alt_mem_ext_ram = 0x00800000 ;

__alt_mem_epcs_controller = 0x00900000 ;

__alt_mem_sdram = 0x01100000 ;

-----------------------------------------------------------------------------------------------------

But when I use this script nothing really happens when I starte up the program.

What am I missing???

Can this be done with this script or must it be done with the ELF tools???? If yes how with the ELF tools????

Hope someone can help me since the documentation for this is none existing

Best regards

GreateWhite.DK

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  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    21 years ago

    The bootm command is now implemented. You'll also

    need to get the mkimage utility to create the u-boot

    image file. Pre-builts, sources, etc updated at:

    http://www.psyent.com/download (http://www.psyent.com/download)

    I tested by booting a gzipped Microtronix linux kernel

    on the Altera 1C20 devkit board. Result were pretty

    good:

    vmlinux.bin: 1.6 MB (original binary)

    vmlinux.img: 678 KB (gzipped u-boot image).

    BTW: see the README in the mkimage zip file

    for instructions.

    Regards,

    --Scott
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    21 years ago

    Hi Scott

    Really nice that you have finished it.

    Have gotten my own loader up and running now and it runs super http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/smile.gif

    Tried using your u-boot because you get a better compression from your GZip that I get from using my alogoritme.(I only get the 1.6MB to about 900k)

    But when I try starting up the u-boot as instructed in the readme file I get

    U-Boot 1.1.2 (Sep 17 2004 - 16:15:21)

    CPU : Nios-II

    SYSID : 948685d8, Wed Apr 28 05:53:44 2004

    BOARD : Psyent PK-1C20

    *** Warning - bad CRC, using default environment

    ==>

    So when I get some spare time I will take a more close look at it.

    Thx again for all your help Scott you have many buddy points in my book http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/biggrin.gif

    Regards

    GreateWhite.DK
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    21 years ago

    > *** Warning - bad CRC, using default environment

    This is normal behavior when the environment has not been saved to flash.

    u-boot supports environment variables. These variables are simply name-value pairs.

    If you execute the &#39;printenv&#39; command, you should see something like:

    stdin=serial

    stdout=serial

    ipaddr=192.168.2.21

    You can add variables to the u-boot environment using the &#39;setenv&#39; command.

    For example, to set the environment variable &#39;netmask&#39; to &#39;255.255.255.0&#39;:

    ==> setenv netmask 255.255.255.0

    When u-boot starts up, it trys to read saved environment variables from

    a configured address. In the case of the PK1C20 configuration, it uses the

    flash sector at 0x0000_3000. The environment is stored as a 32-bit CRC,

    followed by strings formatted as "name=value\0". If the CRC is good,

    u-boot uses the variables from flash, otherwise it uses a set of default

    variables that are created at compile time.

    To save your environment to flash (and prevent subsequent warnings at

    startup), just use the &#39;saveenv&#39; command. Provided that you flash programming

    implementation is correct, u-boot will copy the variables to flash and write

    the 32-bit CRC.

    The enviroment variables are quite handy for storing things such as serial

    numbers, default ip addresses, etc. They may also be used in commands

    and u-boot scripts. For example:

    ==> setenv serverip 10.0.41.40

    ==> ping $serverip

    A more complicated example would be to set the bootcmd variable to load a

    kernel image via tftp, then boot the kernel. The bootcmd variable can be

    configured to automatically run at startup after a configured delay (in this

    case 5 seconds):

    ==> setenv bootcmd "tftpboot 800000 linux.img; bootm 800000"

    ==> setenv bootdelay 5

    ==> saveenv

    Anyway, there&#39;s a long-winded description ;-) of some things you can do with

    the environment.

    Regards,

    --Scott