The IGEP X-loader

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Summary

X-Loader, an initial program loader for Embedded boards based on OMAP processors.

Features and Limitations

Improvements & Modifications

  • Malloc/free functionality.
  • Mtd framework and onenand support, removed the old onenand drivers.
  • Jffs2 support using mtd & onenand support (Read Only).
  • Crc32 and zlib.
  • Jffs2 zlib compression support (Read Only).
  • Dual boot mmc & onenand with mmc highest priority.
  • Linux kernel boot directly (Support for 2.6.22 and highest version kernels)
  • Linux kernel supported images: vmlinuz, bzImage and zImage.
  • Support for loading Linux Ram disk (EXPERIMENTAL)
  • "ini" files parser.
  • The configuration resides in a plain txt (ini format file).
  • Support Windows & Linux formating ini files.
  • Boot from mmc, onenand, or mix with mmc highest priority.
  • Codeblocks project and compilation rules.
  • Support for gcc 4.5.1.

Limitations

  • The ini configuration file it's limited to max size: 16 KiB
  • Kernel Command line parameters it's limited to: 4 KiB
  • Malloc it's limited to 32 MiB.
  • Cannot write comments in lines with tag=value

TODO

  • Support for IGEP0030 - Family boards.
  • Support for other OMAP/DM/AM processor boards.
  • Remove compilation warnings.
  • Comments in tag lines

STATUS

  • Support IGEP0020 Revision B & C family boards.
  • Tested with IGEPv2 (DM3730@1Ghz and 512/512 MB Ram/Onenand)
  • Tested with IGEPv2 (AM3703@1Ghz and 512/512 MB Ram/Onenand)
  • Tested with IGEPv2 (OMAP3530@720Mhz and 512/512 MB Ram/Onenand)

Build Procedure

Build with Ubuntu Cross Compiler gcc 4.5.1

EnviromentUbuntu 10.10

Install the cross compiler if you not do it before.

apt-get install cpp-4.5-arm-linux-gnueabi g++-4.5-arm-linux-gnueabi

Setup the board settings

make igep0020-sdcard_config

Build

make

Sign the binary x-loader

You should execute contrib/signGP for sign the xloader. 

contrib/signGP x-load.bin
The signed x-loader it's named: x-load.bin.ift

Build with IGEP SDK

Setup the Enviroment

source /usr/local/poky/eabi-glibc/environment-setup-arm-none-linux-gnueabi

Setup the board settings

make igep0020-sdcard_config

Build

make CROSS_COMPILE=arm-none-linux-gnueabi-

Sign the binary x-loader

You should execute contrib/signGP for sign the xloader. 

contrib/signGP x-load.bin
The signed x-loader it's named: x-load.bin.ift

Build Native

Configure the board settings

make igep0020-sdcard_config

Edit the variable CFLAGS and add the option: -fno-stack-protector
CFLAGS := $(CPPFLAGS) -Wall -Wstrict-prototypes -fno-stack-protector

Build

make CROSS_COMPILE=arm-none-linux-gnueabi-

Sign the binary x-loader

You should execute contrib/signGP for sign the xloader. 

contrib/signGP x-load.bin
The signed x-loader it's named: x-load.bin.ift

BOOT

The IGEP X-Loader must reside in the microSD card or in the OneNand.

MMC Boot

Prepare the microsd card

You can follow this howto about how prepare the microsd card.

Get a new mmc and create two partitions, the first one must be fat and the second one can be formated in any format type supported by linux kernel.

Copy the files in the first (FAT) partition

In the first partition you must copy in this order:

  1. x-loader.bin.ift (you must rename this file to MLO) / This is a signed image using contrib/signGP tool
  2. x-loader configuration file igep.ini also you can change the configuration file name editing the file: igep0020-sdcard.h (#define IGEP_BOOT_CFG_INI_FILE "igep.ini")
  3. Your desired kernel image.

Load Order: 

  48 /* Linux Images */
  49 const char* LinuxImageNames [] = {
  50         "kparam"   /* Use kparam first */
  51         "zImage",   /* jffs2 it's case sensitive */
  52         "zimage",   /* fat name it's not case sentitive */
  53         "vmlinuz",
  54         "bzImage",
  55         "bzimage",
  56         0,
  57 };

or you can set the name for your kernel in the configuration file using the tag: kImageName

Don't use a uImage kernel format (from uboot), only standard kernel formats it's supported.

kernel build command example: 

$make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- zImage modules

Second Partition

Copy all your rootfs in this second partition.

Also you can use the linaro 10.11 minimal image download the image and untar (as root) in your microsd card second partition.

Remember install the kernel modules in this partition.

Example: 

sudo make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- modules_install INSTALL_MOD_PATH=[path to your target rootfs]

OneNand Boot

OneNand Partitions

We suggest use minimum 3 partitions on the OneNand. 

MTD partitions on "omap2-onenand":
(a) 0x000000000000-0x000000080000 : "X-Loader"
(b) 0x000000080000-0x000000c80000 : "Boot"
(c) 0x000000c80000-0x000020000000 : "File System"

X-Loader Partition

  • Not fs formated (onenand raw)
  • Suggested size: 0x80000 (512 KiB)
  • The xloader must be signed before copy it into the flash memory.

You should copy the x-loader in the firsts 4 blocks (first 512 KiB), this is not a formated partition due the ROM not permits boot from a formated partition in flash, you should use flash_eraseall and nandwrite for copy x-loader in the first blocks. 

<u>Suggested procedure:
</u>
Erase and copy the x-loader into the first flash partition:
$nand_eraseall /dev/mtd0
$nandwrite -p /dev/mtd0 <x-loader>

Sign x-loader:
You should execute contrib/signGP for sign the xloader that resides inside the flash memory.
contrib/signGP x-load.bin
The signed x-loader it's named: x-load.bin.ift

Due the Onenand 512 MiB has two dies it's necessary split the x-loader and convert it to a 1 die binary.
This is a know OMAP/DM/AM OneNand/Nand boot limitation.

This is the procedure for create the x-loader OneNand binary:
You should execute: (You can use copy paste in your console)
split -b 2K x-load.bin.ift split-
for file in `ls split-a?`; do cat $file >> x-load-ddp.bin.ift; cat $file >> x-load-ddp.bin.ift; done

This last command generate a file named x-load-ddp.bin.ift this is the x-loader for copy it in the OneNand.

Boot Partition

  • fs used jffs2 zlib compressed filesystem.
  • Suggested size: 0xC00000 (12 MiB).

X-Loader only support jffs2 partitions for boot partition.

Prepare the boot partition for the first use:

You should follow the same procedure used for copy the x-loader in the first partition. 

Suggested procedure:
Erase and copy the x-loader into the first flash partition:
$nand_eraseall /dev/mtd0
$nandwrite -p /dev/mtd0 <your_boot_initial_jffs2_file>


Your initial boot partition can be a empty file the first time.

Next uses:

You can mount the partition over your boot directory in the rootfs 

$mount /dev/mtdblck1 /boot

And you can use the cp command for copy your kernel and igep.ini configuration file. 

$cp igep.ini /boot

Rootfs Partition

  • fs (your prefered fs supported by linux, maybe a good choice it should be ubifs)
  • Size, all or you can create more partitions if you wish ... emoticon

Boot Priority

XLoader first try load from mmc and if it fails then try from OneNand.

MLO (x-loader), igep.ini, zImage from MMC
If all it's present in the mmc it don't try to boot from Onenand.

MLO (x-loader) in MMC, igep.ini and zImage in Onenand.
If only MLO it's provided this one try to load the other information from the Onenand.

It means that XLoader always try to load the information from MMC and if it fails then try to load from OneNand.

Configuration file: igep.ini

This entry in wikipedia can help you how a ini file it's structured.

The actual XLoader can handle two kind tags:

[kernel] Used for internal XLoader setup.

[kparams] Used for pass the linux kernel parameters.

TAG: [kernel] 

   1 [kernel]
   2 kaddress=0x80008000
   3 rdaddress=0x84000000
   4 serial.low=00000001
   5 serial.high=00000000
   6 revision=0001
   7 kImageName=zImage-test
   8 kRdImageName=rdImage-test

TAG: [kparams]

In this tag you can add all kernel parameters that you need, this is only an example: 

  10 [kparams]
  11 console=ttyS2,115200n8
  12 ;earlyprintk=serial,ttyS2,115200
  13 mem=512M
  14 boot_delay=0
  15 ;mpurate=800
  16 ;loglevel=7
  17 omapfb.mode=dvi:1024x768MR-16@60\r
  18 smsc911x.mac=0xb2,0xb0,0x14,0xb5,0xcd,0xde\r
  19 ;ubi.mtd=2
  20 ;root=ubi0:igep0020-rootfs
  21 ;rootfstype=ubifs
  22 root=/dev/mmcblk0p2 rw rootwait

Also remember you can comment any line using ';' or '#' characters.

FAQ

How I can boot from NFS

Yes, you should add this parameters in the kparams tag: 

#smsc911x.mac fix your mac address
smsc911x.mac=0xb2,0xb0,0x14,0xb5,0xcd,0xde
# IP set you IP settings <local_ip>:<server_ip>:<gateway>:<network_mask>::<interface>:
ip=192.168.2.123:192.168.2.105:192.168.2.1:255.255.255.0::eth0:
# Set root as nfs
root=/dev/nfs
# Set your NFS root path as <server_ip>:<rootfs_path>
nfsroot=192.168.2.105:/srv/nfs/linaro_minimal


6 Contribution & Support & Bugs Report

Contributions to this project be welcome and you can send your patches to support@iseebcn.com or you can use the igep forum for it.
You can access to IGEP-x-Loader repository using our git at git.igep.es
IGEP IRC Channel: http://webchat.freenode.net/?channels=igep



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