Setting up U-Boot

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U-Boot

U-Boot is another popular boot loader. A preliminary port to the Xtensa architecture is now available. See U-Boot Sources (GIT Summary). Or, to access this tree using git directly, use something like: 

$ git clone git://git.linux-xtensa.org/git/u-boot/u-boot-xtensa.git u-boot

(Note: This path is subject to change.)

Before you can build U-Boot you must have built the toolchain for XTensa core. Set your PATH to point to the toolchain built using buildroot. For example: 

   $ export PATH="<workdir>/buildroot/build_xtensa_<cname>/staging_dir/usr/bin:$PATH"

where <cname> is the name of the Xtensa core variant you wish to build for (e.g., dc232b).

To build U-Boot, use the cloned git tree pulled above, change to the top level of the tree, u-boot', then configure it for your board and Xtensa core variant as follows: 

cd u-boot
make <cname>_<board>_config

This should only take a few seconds. For example, to build U-boot for the 'xtav60' board and 'dc232b' core, type: 

$ cd u-boot
$ make dc232b_xtav60_config

or for a 'xtav200' board type 

 $ make dc232b_xtav200_config

Only boards and core variants currently supported in the tree can be built out of the box. Headers for supported cores can be found in the tree under include/asm-xtensa/variant-<cname>. The core specific headers are described in the doc/README.xtensa file. To support a new core, these headers must be copied from the overlay in the same way as for the linux kernel.

After the configuration step, to actually build U-Boot, simply: 

$ make all

This will take a quite a few minutes.

Next, start xt-gdb and load u-boot from the top of the git repository: 

 $ cd u-boot-xtensa
 $ xt-gdb -n
 $ file u-boot
 $ target remote localhost:20000 0
 $ reset
 $ load
 $ break panic
 $ continue

Hopefully u-boot will start and display on the LCD 

 U-Boot 50.00 Mhz

Often you will be starting with a flash in an unknown state and it's best to unprotect and erase the entire flash. Just type protect off all followed by erase all: 

   U-Boot> protect off all
   Un-Protect Flash Bank # 1
   ................................................................................................................................... done
   U-Boot>  erase all
   Erase Flash Bank # 1 
   ..........................................................................................................
   Flash erase timeout at address f8d40000 da0
   Flash erase error at address f8d40000
   ........................ done
   U-Boot>

The timeout and error messages are likley just warning messages and you board has been errased. You can see that with the flash info command flinfo. Below is an example with a LX200 board, which has a much larger flash than the smaller LX60: 

  U-Boot> flinfo

   Bank # 1: CFI conformant FLASH (16 x 16)  Size: 16 MB in 131 Sectors
     Intel Extended command set, Manufacturer ID: 0x89, Device ID: 0x18
     Erase timeout: 4096 ms, write timeout: 1 ms
     Buffer write timeout: 2 ms, buffer size: 64 bytes

     Sector Start Addresses:
     F8000000 E      F8020000 E      F8040000 E      F8060000 E      F8080000 E
     F80A0000 E      F80C0000 E      F80E0000 E      F8100000 E      F8120000 E
     F8140000 E      F8160000 E      F8180000 E      F81A0000 E      F81C0000 E
     F81E0000 E      F8200000 E      F8220000 E      F8240000 E      F8260000 E
     F8280000 E      F82A0000 E      F82C0000 E      F82E0000 E      F8300000 E
     F8320000 E      F8340000 E      F8360000 E      F8380000 E      F83A0000 E
     F83C0000 E      F83E0000 E      F8400000 E      F8420000 E      F8440000 E
     F8460000 E      F8480000 E      F84A0000 E      F84C0000 E      F84E0000 E
     F8500000 E      F8520000 E      F8540000 E      F8560000 E      F8580000 E
     F85A0000 E      F85C0000 E      F85E0000 E      F8600000 E      F8620000 E
     F8640000 E      F8660000 E      F8680000 E      F86A0000 E      F86C0000 E
     F86E0000 E      F8700000 E      F8720000 E      F8740000 E      F8760000 E
     F8780000 E      F87A0000 E      F87C0000 E      F87E0000 E      F8800000 E
     F8820000 E      F8840000 E      F8860000 E      F8880000 E      F88A0000 E
     F88C0000 E      F88E0000 E      F8900000 E      F8920000 E      F8940000 E
     F8960000 E      F8980000 E      F89A0000 E      F89C0000 E      F89E0000 E
     F8A00000 E      F8A20000 E      F8A40000 E      F8A60000 E      F8A80000 E
     F8AA0000 E      F8AC0000 E      F8AE0000 E      F8B00000 E      F8B20000 E
     F8B40000 E      F8B60000 E      F8B80000 E      F8BA0000 E      F8BC0000 E
     F8BE0000 E      F8C00000 E      F8C20000 E      F8C40000 E      F8C60000 E
     F8C80000 E      F8CA0000 E      F8CC0000 E      F8CE0000 E      F8D00000 E
     F8D20000 E      F8D40000 E      F8D60000 E      F8D80000 E      F8DA0000 E
     F8DC0000 E      F8DE0000 E      F8E00000 E      F8E20000 E      F8E40000 E
     F8E60000 E      F8E80000 E      F8EA0000 E      F8EC0000 E      F8EE0000 E
     F8F00000 E      F8F20000 E      F8F40000 E      F8F60000 E      F8F80000 E
     F8FA0000 E      F8FC0000 E      F8FE0000 E      F8FE8000 E      F8FF0000 E
     F8FF8000 E
   U-Boot>

Now set your U-Boot environment variables to point to your DHCP and TFTP server. At Tensilica we use a machine in the RTOS group called rtos-lab2: 

   U-Boot> setenv serverip 192.168.11.78           rtos-lab2
   U-Boot> setenv ipaddr 192.168.11.95             I/P address of host running on the LX60/LX200
   U-Boot> setenv bootfile u-boot.bin
   U-Boot> saveenv
   Saving Environment to Flash...
   .... done
   Un-Protected 4 sectors
   Erasing Flash...
   .... done
   Erased 4 sectors
   Writing to Flash... done
   .... done
   Protected 4 sectors
   U-Boot>


Next, download 'u-boot.bin' from the tftp server: 

 tftpboot
   TFTP from server 192.168.11.78; our IP address is 192.168.11.95
   Filename 'u-boot.bin'.
   Load address: 0xd2000000
   Loading: T ########
   done
   Bytes transferred = 107592 (1a448 hex)

on a LX200 we have much more space and can easily fit a version of U-boot that has been compiled without optimization to make debugging much easier, So in this case the image is a bit larger: 

   U-Boot> tftpboot
   Using open_ethernet device
   TFTP from server 192.168.11.78; our IP address is 192.168.11.95
   Filename 'u-boot.bin'.
   Load address: 0xd2000000
   Loading: ###############
   done
   Bytes transferred = 205852 (3241c hex)
   U-Boot>


Note that for both the LX200 and the LX60 that the image is a bit less than 2 sectors, so turn off protection on the 1st two sectors and erase the current contents. For the LX60 you do this: 

 U-Boot> protect off F8000000 F801FFFF
 ... done
 Un-Protected 2 sectors
 
 U-Boot> erase F8000000 F801FFFF
       erase F8000000 F801FFFF
       ... done

For the LX200 the starting address is the same as with the LX60 but the last addesss is twice as high: 

 U-Boot> protect off F8000000 F803FFFF
 ... done
 Un-Protected 2 sectors
 
 U-Boot> erase F8000000 F803FFFF
 Erased 2 sectors
 U-Boot>

Finally we protect these first two sectors so that U-Boot isn't easily errased by accident. Below is what it looks like on a LX200 with a subsequent display of the flash info: 

  U-Boot> protect on F8000000 F803FFFF
   .. done
   Protected 2 sectors
   U-Boot> flinfo

   Bank # 1: CFI conformant FLASH (16 x 16)  Size: 16 MB in 131 Sectors
     Intel Extended command set, Manufacturer ID: 0x89, Device ID: 0x18
     Erase timeout: 4096 ms, write timeout: 1 ms
     Buffer write timeout: 2 ms, buffer size: 64 bytes

     Sector Start Addresses:
     F8000000   RO   F8020000   RO   F8040000 E      F8060000 E      F8080000 E
     F80A0000 E      F80C0000 E      F80E0000 E      F8100000 E      F8120000 E
     F8140000 E      F8160000 E      F8180000 E      F81A0000 E      F81C0000 E
     F81E0000 E      F8200000 E      F8220000 E      F8240000 E      F8260000 E
     F8280000 E      F82A0000 E      F82C0000 E      F82E0000 E      F8300000 E
     F8320000 E      F8340000 E      F8360000 E      F8380000 E      F83A0000 E
     F83C0000 E      F83E0000 E      F8400000 E      F8420000 E      F8440000 E
     F8460000 E      F8480000 E      F84A0000 E      F84C0000 E      F84E0000 E
     F8500000 E      F8520000 E      F8540000 E      F8560000 E      F8580000 E
     F85A0000 E      F85C0000 E      F85E0000 E      F8600000 E      F8620000 E
     F8640000 E      F8660000 E      F8680000 E      F86A0000 E      F86C0000 E
     F86E0000 E      F8700000 E      F8720000 E      F8740000 E      F8760000 E
     F8780000 E      F87A0000 E      F87C0000 E      F87E0000 E      F8800000 E
     F8820000 E      F8840000 E      F8860000 E      F8880000 E      F88A0000 E
     F88C0000 E      F88E0000 E      F8900000 E      F8920000 E      F8940000 E
     F8960000 E      F8980000 E      F89A0000 E      F89C0000 E      F89E0000 E
     F8A00000 E      F8A20000 E      F8A40000 E      F8A60000 E      F8A80000 E
     F8AA0000 E      F8AC0000 E      F8AE0000 E      F8B00000 E      F8B20000 E
     F8B40000 E      F8B60000 E      F8B80000 E      F8BA0000 E      F8BC0000 E
     F8BE0000 E      F8C00000 E      F8C20000 E      F8C40000 E      F8C60000 E
     F8C80000 E      F8CA0000 E      F8CC0000 E      F8CE0000 E      F8D00000 E
     F8D20000 E      F8D40000 E      F8D60000 E      F8D80000 E      F8DA0000 E
     F8DC0000 E      F8DE0000 E      F8E00000 E      F8E20000 E      F8E40000 E
     F8E60000 E      F8E80000 E      F8EA0000 E      F8EC0000 E      F8EE0000 E
     F8F00000 E      F8F20000 E      F8F40000 E      F8F60000 E      F8F80000 E
     F8FA0000 E      F8FC0000 E      F8FE0000  RO    F8FE8000  RO    F8FF0000   RO
     F8FF8000  RO
   U-Boot>

Note that the U-Boot saveenv command Erassed and protected the last to sectors of this LX200.


Now copy the the image of u-boot.bin in memory to the flash. For the XL60 you copy 0x20000 bytes from 0xd2000000 to 0XF8000000: 

 cp.b d2000000 F8000000 20000
 Copy to Flash... done

For the LX200 you copy 0x40000 bytes from 0xd2000000 to 0XF8000000: 

 cp.b d2000000 F8000000 40000
 Copy to Flash... done

Now U-boot has been saved at the beginning of the flash and can be easy seen with the flash info command. On the LX200 it should look like this: 

   U-Boot> flinfo

   Bank # 1: CFI conformant FLASH (16 x 16)  Size: 16 MB in 131 Sectors
     Intel Extended command set, Manufacturer ID: 0x89, Device ID: 0x18
     Erase timeout: 4096 ms, write timeout: 1 ms
     Buffer write timeout: 2 ms, buffer size: 64 bytes

     Sector Start Addresses:
     F8000000        F8020000        F8040000 E      F8060000 E      F8080000 E
     F80A0000 E      F80C0000 E      F80E0000 E      F8100000 E      F8120000 E
     F8140000 E      F8160000 E      F8180000 E      F81A0000 E      F81C0000 E
     F81E0000 E      F8200000 E      F8220000 E      F8240000 E      F8260000 E
     F8280000 E      F82A0000 E      F82C0000 E      F82E0000 E      F8300000 E
     F8320000 E      F8340000 E      F8360000 E      F8380000 E      F83A0000 E
     F83C0000 E      F83E0000 E      F8400000 E      F8420000 E      F8440000 E
     F8460000 E      F8480000 E      F84A0000 E      F84C0000 E      F84E0000 E
     F8500000 E      F8520000 E      F8540000 E      F8560000 E      F8580000 E
     F85A0000 E      F85C0000 E      F85E0000 E      F8600000 E      F8620000 E
     F8640000 E      F8660000 E      F8680000 E      F86A0000 E      F86C0000 E
     F86E0000 E      F8700000 E      F8720000 E      F8740000 E      F8760000 E
     F8780000 E      F87A0000 E      F87C0000 E      F87E0000 E      F8800000 E
     F8820000 E      F8840000 E      F8860000 E      F8880000 E      F88A0000 E
     F88C0000 E      F88E0000 E      F8900000 E      F8920000 E      F8940000 E
     F8960000 E      F8980000 E      F89A0000 E      F89C0000 E      F89E0000 E
     F8A00000 E      F8A20000 E      F8A40000 E      F8A60000 E      F8A80000 E
     F8AA0000 E      F8AC0000 E      F8AE0000 E      F8B00000 E      F8B20000 E
     F8B40000 E      F8B60000 E      F8B80000 E      F8BA0000 E      F8BC0000 E
     F8BE0000 E      F8C00000 E      F8C20000 E      F8C40000 E      F8C60000 E
     F8C80000 E      F8CA0000 E      F8CC0000 E      F8CE0000 E      F8D00000 E
     F8D20000 E      F8D40000 E      F8D60000 E      F8D80000 E      F8DA0000 E
     F8DC0000 E      F8DE0000 E      F8E00000 E      F8E20000 E      F8E40000 E
     F8E60000 E      F8E80000 E      F8EA0000 E      F8EC0000 E      F8EE0000 E
     F8F00000 E      F8F20000 E      F8F40000 E      F8F60000 E      F8F80000 E
     F8FA0000 E      F8FC0000 E      F8FE0000 E      F8FE8000 E      F8FF0000   RO
     F8FF8000   RO
   U-Boot>

On both the LX60 and the LX200 now move DIP switch 8 to the ON position, power cycle the LX60, and you should see U-boot in the LCD display and the serial console should print something like the following on the LX60: 

 U-Boot 1.3.2 (Aug 27 2009 - 18:23:04)
 
 CPU:    Xtensa dc232b at 50.00 MHz
 Board:  XT-AV60: Avnet board + Xilinx LX60 FPGA + Tensilica bitstream
 SysRAM: 64 MB
 Flash:  4 MB
 In:    serial
 Out:   serial
 Err:   serial
 MAC:
 U-Boot>

For the LX200 you should see something like the following. 

  U-Boot 2009.08-00060-g3aa8b68-dirty (Sep 10 2009 - 01:19:31)

   CPU:    Xtensa test_mmuhifi_c3 at 41.6777 MHz
   Board:  XT-AV200: Avnet board + Xilinx LX200 FPGA + Tensilica bitstream
   SysRAM: 96 MB
   *** Warning - bad CRC, using default environment

   Flash: 16 MB
   In:    serial
   Out:   serial
   Err:   serial
   MAC:
   U-Boot>
   Timed out waiting for command

   U-Boot> flinfo

   Bank # 1: CFI conformant FLASH (16 x 16)  Size: 16 MB in 131 Sectors
     Intel Extended command set, Manufacturer ID: 0x89, Device ID: 0x18
     Erase timeout: 4096 ms, write timeout: 1 ms
     Buffer write timeout: 2 ms, buffer size: 64 bytes

     Sector Start Addresses:
     F8000000   RO   F8020000   RO   F8040000 E RO   F8060000 E RO   F8080000 E RO
     F80A0000 E RO   F80C0000 E RO   F80E0000 E RO   F8100000 E RO   F8120000 E RO
     F8140000 E RO   F8160000 E RO   F8180000 E RO   F81A0000 E RO   F81C0000 E RO
     F81E0000 E RO   F8200000 E RO   F8220000 E RO   F8240000 E RO   F8260000 E RO
     F8280000 E RO   F82A0000 E RO   F82C0000 E RO   F82E0000 E RO   F8300000 E RO
     F8320000 E RO   F8340000 E RO   F8360000 E RO   F8380000 E RO   F83A0000 E RO
     F83C0000 E RO   F83E0000 E RO   F8400000 E RO   F8420000 E RO   F8440000 E RO
     F8460000 E RO   F8480000 E RO   F84A0000 E RO   F84C0000 E RO   F84E0000 E RO
     F8500000 E RO   F8520000 E RO   F8540000 E RO   F8560000 E RO   F8580000 E RO
     F85A0000 E RO   F85C0000 E RO   F85E0000 E RO   F8600000 E RO   F8620000 E RO
     F8640000 E RO   F8660000 E RO   F8680000 E RO   F86A0000 E RO   F86C0000 E RO
     F86E0000 E RO   F8700000 E RO   F8720000 E RO   F8740000 E RO   F8760000 E RO
     F8780000 E RO   F87A0000 E RO   F87C0000 E RO   F87E0000 E RO   F8800000 E RO
     F8820000 E RO   F8840000 E RO   F8860000 E RO   F8880000 E RO   F88A0000 E RO
     F88C0000 E RO   F88E0000 E RO   F8900000 E RO   F8920000 E RO   F8940000 E RO
     F8960000 E RO   F8980000 E RO   F89A0000 E RO   F89C0000 E RO   F89E0000 E RO
     F8A00000 E RO   F8A20000 E RO   F8A40000 E RO   F8A60000 E RO   F8A80000 E RO
     F8AA0000 E RO   F8AC0000 E RO   F8AE0000 E RO   F8B00000 E RO   F8B20000 E RO
     F8B40000 E RO   F8B60000 E RO   F8B80000 E RO   F8BA0000 E RO   F8BC0000 E RO
     F8BE0000 E RO   F8C00000 E RO   F8C20000 E RO   F8C40000 E RO   F8C60000 E RO
     F8C80000 E RO   F8CA0000 E RO   F8CC0000 E RO   F8CE0000 E RO   F8D00000 E RO
     F8D20000 E RO   F8D40000 E RO   F8D60000 E RO   F8D80000 E RO   F8DA0000 E RO
     F8DC0000 E RO   F8DE0000 E RO   F8E00000 E RO   F8E20000 E RO   F8E40000 E RO
     F8E60000 E RO   F8E80000 E RO   F8EA0000 E RO   F8EC0000 E RO   F8EE0000 E RO
     F8F00000 E RO   F8F20000 E RO   F8F40000 E RO   F8F60000 E RO   F8F80000 E RO
     F8FA0000 E RO   F8FC0000 E RO   F8FE0000   RO   F8FE8000   RO   F8FF0000   RO
     F8FF8000 E RO
   U-Boot>

Note that the 1st two sectors with U-Boot saved in them came up as not being errased ('E') but that all sectors came up Read Only (RO). Same with the last four sectors that the U-Boot saveenv command Errased. This is likely a bug that we have been investigating and will be discussing with the U-Boot developers sometime in the future prior to pushing our U-boot changes upstream.


Further details on U-Boot in general are in the generic README at the top of the U-Boot tree. Details specific to the Xtensa architecture are in doc/README.xtensa. Details specific to a board are in board[/<family>]/<board>/README (for example board/avnet/xtav60/README).

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