buildroot_ido-som2d01

Buildroot for ido-som2d01 based boards.

Wha?

This is a buildroot setup for the various ido-som2d01 based boards.

• The som2d01 with an SSD201 or SSD202D
• The sbc2d06
• The sbc2d70

This is not a all singing all dancing OS image for these things. This is meant to be something that builds a complete working set of binaries that you can work from.

Flashing a blank module

• You need to flash at least the CIS blob, the IPL blob and the u-boot SPL. Right now you need to do this with the vendor ISP tool. Flashrom can drive the i2c interface to write SPI NOR but it cannot do SPI NAND yet so there is no alternative right now.

  • See here for information on this.
  • Note that the u-boot SPL is currently called idosom2d01-ipl. At some point the u-boot SPL will replace the vendor IPL blob.

• The main u-boot binary here lives in a UBI partition so that bad block recovery etc actually works. Loading the UBI partition data with the ISP tool is very very slow so you don't to do that. The u-boot SPL is capable of loading the main u-boot binary over serial. The first time you boot you need to send u-boot with ymodem. This should be a lot faster than trying to flash the UBI partition via the ISP tool.

• Now we need to format the part of the flash we'll use for the UBI partitions. idosom2d01-kernel-rescue.fit is a micro system with a kernel and just enough userland to setup the flash.

• If you board has ethernet you can put idosom2d01-kernel-rescue.fit onto a TFTP server somewhere and load it via ethernet.

  setenv loadaddr 0x22000000; dhcp 192.168.3.235:idosom2d01-kernel-rescue.fit; bootm
  

• If you don't have ethernet you can load over serial with ymodem. This will be insanely slow though so only do this as last resort.

  setenv loadaddr 0x22000000; loady; bootm
  

  Depending on your serial interface you might be able to increase the baud rate used during the transfer.

  If you are really lucky something like this might work:

  setenv loadaddr 0x22000000; loady ${loadaddr} 230400; bootm
  

  or

  setenv loadaddr 0x22000000; loady ${loadaddr} 460800; bootm
  

  Eitherway, you should now be booted in a Linux environment where you can finish off flashing the required images.

  Note for SSD202D modules you must use bootm ${loadaddr}#ssd202d-som2d01 to use the SSD202D device tree otherwise the kernel locks up at boot.

Notes for SBC2D06

To write the GCIS, IPL and u-boot SPL on the module on the SBC2D06 you need to move the jumpers.

This is the position for using the usb port for serial:

This is the position for using the ISP connector for flashing.

You need to move the jumpers into the flashing position when using the the ISP tool and back again when you need to access the serial console.

Using the rescue image to complete flashing

• First we need to create the UBI partitions

  ubiformat /dev/mtd1
  ubiattach -m 1
  ubimkvol /dev/ubi0 -N uboot -s 1MiB -t static
  ubimkvol /dev/ubi0 -N env -s 256KiB
  ubimkvol /dev/ubi0 -N kernel -s 16MiB
  ubimkvol /dev/ubi0 -N rescue -s 16MiB
  ubimkvol /dev/ubi0 -N rootfs -m
  

• Now we should pull the rescue image and load it into the rescue partition. If something goes wrong once we have the rescue image in the flash it's a lot easier to progress. Especially if you are using serial.

  ** tftp instructions here **

  • For serial run rz and then send idosom2d01-kernel-rescue.fit.
  • Now run:

  ubiupdatevol /dev/ubi0_3 idosom2d01-kernel-rescue.fit
  

• Next we should pull the u-boot image and flash it.

  • For serial run rz and then send idosom2d01-u-boot.img.
  • Now run:

  ubiupdatevol /dev/ubi0_0 idosom2d01-u-boot.img
  

• At this point your module should be able to boot into u-boot directly without needing serial and you should be able to boot back into the rescue setup by running:

  setenv loadaddr 0x22000000; ubi readvol ${loadaddr} rescue 0x800000; bootm
  

• Now lets get the kernel and rootfs images

  • For serial run rz and then send idosom2d01-kernel.fit and idosom2d01-rootfs.squashfs
  • For tftp something like:

  tftp -b 4096 -g -r idosom2d01-kernel.fit 192.168.3.235
  tftp -b 4096 -g -r idosom2d01-rootfs.squashfs 192.168.3.235
  

  • Now run:

  ubiupdatevol /dev/ubi0_2 idosom2d01-kernel.fit
  ubiupdatevol /dev/ubi0_4 idosom2d01-rootfs.squashfs
  

• Now everything is flashed, you should be able to boot the normal kernel with a more feature rich rootfs. The supplied rootfs is a read only squashfs. If you want to use ubifs for a read/write filesystem you can do that but it won't be detailed here.

  setenv bootargs console=ttyS0,115200 ubi.mtd=1 ubi.block=0,4 root=/dev/ubiblock0_4 clk_ignore_unused
  setenv bootcmd 'setenv loadaddr 0x22000000; ubi readvol ${loadaddr} kernel 0x800000; bootm ${loadaddr}#<your board type>'
  

• Have fun!

Appendix: Creating ubi layout in u-boot

ubi createvol uboot 0x100000 static
ubi createvol env 0x40000
ubi createvol kernel 0x1000000
ubi createvol rescue 0x1000000
ubi createvol rootfs -