Setting up U-Boot: Difference between revisions

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== LX60 and LX200 U-Boot Installation ==


''('''Note:''' The DC233 isn't currently working and is being actively investigated. We hope to have it working shortly.
[http://www.denx.de/wiki/UBoot U-Boot] is a very popular boot loader; especially within the [http://elinux.org/Bootloader Embedded Linux community]. A preliminary port to the Xtensa architecture is now available at linux-xtensa.org.  See [http://git.linux-xtensa.org/cgi-bin/git.cgi?p=u-boot/u-boot-xtensa.git;a=summary U-Boot Sources (GIT Summary)].  Or, to access this tree using <tt>git</tt> directly, use something like:
  $ '''git clone git://git.linux-xtensa.org/git/u-boot/u-boot-xtensa.git u-boot'''
  $ '''cd u-boot'''
''('''Note:'''  This path is subject to change.)''
The U-Boot git repository has a branch with a HiFi 2 snapshot made for
the LX200 [[SMP HiFi 2 Development Board]]. With this branch you can simply check
out the snapshot_2+SMP branch which includes the binaries which are discussed below:
  $ '''git clone git://git.linux-xtensa.org/git/u-boot/u-boot-xtensa.git u-boot'''
  $ '''cd u-boot'''
  $ '''git branch --track snapshot_2+SMP origin/snapshot_2+SMP'''
  $ '''git checkout snapshot_2+SMP'''
  $ '''ls -l u-boot u-boot.bin tools/mkimage'''
    -rwxr-xr-x 1 piet tensilica  45016 2009-12-07 19:40 tools/mkimage          [This is a small program you need to put in your search path to build kernel U-Boot images]
    -rwxr-xr-x 1 piet tensilica 635339 2009-12-07 19:40 u-boot                  [Started with xt-gdb to bring up the 1st instance of a HiFi 2 U-Boot]
    -rwxr-xr-x 1 piet tensilica 144944 2009-12-07 19:40 u-boot.bin              [Loaded by the 1st instance of U-Boot, it's a HiFi2 version of u-boot that will be put in flash]
  $
Unless you are using a U-Boot snapshot you need to build U-Boot for which you must have built the Buildroot 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., <tt>dc232b</tt> <tt>dc233c</tt>).
To build U-Boot, use the cloned git tree pulled above, you should be at the top level of the tree in the '''u-boot''' directory ,  then configure it for your board and Xtensa core variant as follows:
make distclean
make <cname>'''_<board>_'''config
'dc232b'dc
This should only take a few seconds. For example, to build U-boot for the 'xtav60' board and the older 'dc232b' core with the V2 MMU type:
  $ '''cd u-boot'''
  $ '''make dc232b_xtav60_config'''                                  [NOTE: You can skip this step with the the HiFi-2 snapshot_2+SMP branch; binaries are pre-built]
or for the new 'dc233c' core with the new V3 MMU type:
  $ '''make dc233c_xtav60_config'''                                  [NOTE: You can skip this step with the the HiFi-2 snapshot_2+SMP branch; binaries are pre-built]
or for a 'xtav200' board type with the new 'dc233c' core type:
  $ '''make dc233c_xtav200_config'''                                [NOTE: You can skip this step with the the HiFi-2 snapshot_2+SMP branch; binaries are pre-built] 
or for the snapshot_2+SMP branch you can also build U-Boot for the HiFi 2 core:
  $ make test_mmuhifi_c3_xtav200_config                              [NOTE: You can skip this step with the the HiFi-2 snapshot_2+SMP branch; binaries are pre-built]
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 <tt>include/asm-xtensa/variant-<cname></tt>. The core specific headers are described in the <tt>doc/README.xtensa</tt> 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'''                                                  [NOTE: You can skip this step with the the HiFi-2 snapshot_2+SMP branch; binaries are pre-built]
This will take a quite a few minutes.
Next, start xt-gdb and load u-boot from the top of the git repository:
 
  $ '''xt-gdb -n'''                                                  [NOTE: Even with the HiFi 2 snapshot_2+SMP branch you still may have to put U-Boot on the board]           
  (xt-gdb) '''file u-boot'''
  (xt-gdb) '''target remote localhost:20000 0'''
  (xt-gdb) '''reset'''
  (xt-gdb) '''load'''
  (xt-gdb) '''break panic'''
  (xt-gdb) '''continue'''
Hopefully U-Boot will start, and display on the LCD in the case of a LX60.
  U-Boot 50.00 Mhz
Often you will be starting with the boards 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 preliminary U-Boot environment variables to point to your TFTP server so we can download yet another copy of U-Boot. At Tensilica we use a machine in the RTOS group called rtos-lab2. Folks using the [[SMP HiFi 2 Development Board]] likely have set up their workstation with a TFTP server.     
    U-Boot> '''setenv serverip 192.168.11.78'''          rtos-lab2
or
    U-Boot> '''setenv serverip 192.168.11.55'''          pdelaney_fc9
    U-Boot> '''setenv ipaddr 192.168.11.95'''            I/P address of RTOS5, Piet's LX60; MAC: 00:05:C2:13:6f:0a
    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 using the info we just entered into U-Boot's enviroment variables.
Here for example is the case for a LX60 running the HiFi-2 Bitstream with the older V2 MMU. Note that it starts up
in the D-gazillion (0XD0000000) region:
    U-Boot> '''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)
For the V3 MMU U-Boot is loaded from host pdelaney_fc9 into memory with virtual == physical. Here is a DC233L, with V3 MMU, example:
    U-Boot> tftpboot
    Using open_ethernet device
    TFTP from server 192.168.11.55; our IP address is 192.168.11.95
    Filename 'u-boot.bin'.
    Load address: 0x2000000
    Loading: T ########
    done
    Bytes transferred = 109964 (1ad8c hex)
    U-Boot>
Now things get a bit tricky here for the LX60. The FLASG has '''Two sizes of Flash Sectors'''.
The first 8 sectors are small 0x2000 (8KB) and apparently intended for parameters. The rest
of the 4MB flash is composed of larger 0x10000 (64KB) sectors.  Our code doesn't differentiate
between the sectors and the LX60 hardware is going to map 0XF800,0000 to 0XFE00,0000 so this
makes us use of all 8 of the 8KB sectors and the 1st 64KB sector at F8010000. So we are going
to flash up to F801FFFF below.
On a LX200 we have much more space and can easily fit a version of U-boot that has been compiled without optimization, make debugging much easier.
So in this case the image is a bit larger, but relatively similar to the LX60 (2 sectors):
    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 size, '''(3241c hex)''' in this case, is a bit less than 0x40000 or 10 sectors,
so turn off protection on the 1st 11 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 '''(F8000000)''' is the same as with the LX60 but the last addesss '''(F803FFFF)''' 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>
Now copy the the image of u-boot.bin in memory to the flash. For the XL60 with the '''OLD''' V2 MMU you copy 0x20000
bytes from 0xd2000000 to 0XF8000000:
  U-Boot> '''cp.b d2000000 F8000000 20000'''
  Copy to Flash... done
For the LX60 with the '''NEW''' V3 MMU you copy 0x24000 bytes from 0x2000000 to F8000000:
  U-Boot> '''cp.b 2000000 F8000000 20000'''
  Copy to Flash... done
For the LX200 you copy 0x40000 bytes from 0xd2000000 to 0XF8000000...0XF803FFFF:
  U-Boot> '''cp.b d2000000 F8000000 40000'''
  Copy to Flash... done
Finally we protect these sectors so that U-Boot isn't easily erased by accident.
Below is what it looks like on a LX60 with the New V3 MMU with a subsequent display of the flash info:
    U-Boot> cp.b 2000000 F8000000 2000
    Copy to Flash... done
    U-Boot> flinfo
    Bank # 1: CFI conformant FLASH (16 x 16)  Size: 4 MB in 71 Sectors
      AMD Standard command set, Manufacturer ID: 0x20, Device ID: 0x2257
      Erase timeout: 8192 ms, write timeout: 1 ms
      Sector Start Addresses:
      F8000000        F8002000        F8004000        F8006000        F8008000
      F800A000        F800C000        F800E000        F8010000        F8020000 E
      F8030000 E      F8040000 E      F8050000 E      F8060000 E      F8070000 E
      F8080000 E      F8090000 E      F80A0000 E      F80B0000 E      F80C0000 E
      F80D0000 E      F80E0000 E      F80F0000 E      F8100000 E      F8110000 E
      F8120000 E      F8130000 E      F8140000 E      F8150000 E      F8160000 E
      F8170000 E      F8180000 E      F8190000 E      F81A0000 E      F81B0000 E
      F81C0000 E      F81D0000 E      F81E0000 E      F81F0000 E      F8200000 E
      F8210000 E      F8220000 E      F8230000 E      F8240000 E      F8250000 E
      F8260000 E      F8270000 E      F8280000 E      F8290000 E      F82A0000 E
      F82B0000 E      F82C0000 E      F82D0000 E      F82E0000 E      F82F0000 E
      F8300000 E      F8310000 E      F8320000 E      F8330000 E      F8340000 E
      F8350000 E      F8360000 E      F8370000 E      F8380000 E      F8390000 E
      F83A0000 E      F83B0000 E      F83C0000 E      F83D0000 E      F83E0000
      F83F0000  RO
    U-Boot> protect on F8000000 F802FFFF
    .......... done
    Protected 10 sectors
    U-Boot>
    U-Boot> flinfo
    Bank # 1: CFI conformant FLASH (16 x 16)  Size: 4 MB in 71 Sectors
      AMD Standard command set, Manufacturer ID: 0x20, Device ID: 0x2257
      Erase timeout: 8192 ms, write timeout: 1 ms
      Sector Start Addresses:
      F8000000  RO  F8002000  RO  F8004000  RO  F8006000  RO  F8008000  RO
      F800A000  RO  F800C000  RO  F800E000  RO  F8010000  RO  F8020000 E
      F8030000 E      F8040000 E      F8050000 E      F8060000 E      F8070000 E
      F8080000 E      F8090000 E      F80A0000 E      F80B0000 E      F80C0000 E
      F80D0000 E      F80E0000 E      F80F0000 E      F8100000 E      F8110000 E
      F8120000 E      F8130000 E      F8140000 E      F8150000 E      F8160000 E
      F8170000 E      F8180000 E      F8190000 E      F81A0000 E      F81B0000 E
      F81C0000 E      F81D0000 E      F81E0000 E      F81F0000 E      F8200000 E
      F8210000 E      F8220000 E      F8230000 E      F8240000 E      F8250000 E
      F8260000 E      F8270000 E      F8280000 E      F8290000 E      F82A0000 E
      F82B0000 E      F82C0000 E      F82D0000 E      F82E0000 E      F82F0000 E
      F8300000 E      F8310000 E      F8320000 E      F8330000 E      F8340000 E
      F8350000 E      F8360000 E      F8370000 E      F8380000 E      F8390000 E
      F83A0000 E      F83B0000 E      F83C0000 E      F83D0000 E      F83E0000 
      F83F0000  RO
    U-Boot>
Below is what it looks like on a LX200 with the V2 MMU with a subsequent display of the flash info.
Notice that the Flash Sectors are 10X as large on the LX200:
  U-Boot> '''protect on F8000000 F802FFFF'''
    .. 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 Erased and protected the last four sectors
of this LX200.
On both the LX60 and the LX200 now move DIP switch 8 to the ON position, power cycle the board. On the LX60 you should see U-boot in the LCD display.
The '''LX60''' with the V3 MMU currently fails and is being investigated.
On the '''LX60''' with the V2 MMU the serial console should print something like the following:
 
  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>
On the '''LX200''' you should see something like the following. In this case we also show the flash info command, '''flinfo''', being envoked just after booting U-Boot:
  CPU:    Xtensa test_mmuhifi_c3 at 41.6777 MHz
    Board:  XT-AV200: Avnet board + Xilinx LX200 FPGA + Tensilica bitstream
    SysRAM: 96 MB
    Flash: 16 MB
    In:    serial
    Out:  serial
    Err:  serial
    MAC:
    IP:    192.168.11.95
    U-Boot>
    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  RO'''
    U-Boot>
Note that the 1st two sectors with U-Boot saved in them came up as not being erased ('''E''') but that all sectors came up Read Only ('''RO''').
Same with the last four sectors that the U-Boot '''saveenv''' command Erased. 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 <tt>README</tt> at the top of the U-Boot tree. Details specific to the Xtensa architecture are in <tt>doc/README.xtensa</tt>. Details specific to a board are in <tt>board[/<family>]/<board>/README</tt> (for example <tt>board/avnet/xtav60/README</tt>).

Latest revision as of 23:31, 2 March 2018

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