Building for BeagleBone

Arm Compiler

Setting up cross-compile environment is the first and necessary step.

Distro provided

The easier way is install the default compiler provided by your distribution.

Ubuntu : gcc-arm-linux-gnueabi

Arch Linux : arm-linux-gnueabi-gcc

Debian : ??

Fedora : ??

Linux Mint : ??

• Tip: Do a alias in your environment, where N is the number of processors cores plus one:

$ alias armmake='make -jN ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- '

crosstool-NG

crosstool-NG aims at building toolchains. So, by this way you will build your own cross-compiler, but this requires that you choose an operation system and LibC. Therefore we will build a cross-compiler for Linux/gLibc.

U-Boot

Mainline U-boot

You can use the mainline u-boot for beaglebone.

Get:

$ git clone git://git.denx.de/u-boot.git

Clean:

$ armmake distclean

Configure for BeagleBone:

$ armmake am335x_evm_config

Build:

$ armmake

Test your new U-Boot

You need a microSd card with 2Gb or more. In order to make U-Boot work you will need to create the first partion as FAT32 LBA, bootable, with something like 64 Megabytes.
This command wipes everything from your sdcard and creates that partition.

$ echo -e "o\nn\np\n1\n\n+64M\na\n1\nt\nc\nw\n" | sudo fdisk /dev/MYDISK ; sudo fdisk /dev/MYDISK -l

This comand should print something like:

Disk /dev/sdb: 7948 MB, 7948206080 bytes
16 heads, 4 sectors/track, 242560 cylinders, total 15523840 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x1c524301
    Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *        2048      133119       65536    c  W95 FAT32 (LBA)

The U-Boot compilation generated two files, MLO and uboot.img. Mount the partition that you just created and copy FIRST the MLO file to partition. Then copy the u-boot.img.

$ sudo mount /dev/MYDISK /mnt
$ sudo cp MLO /mnt
$ sudo cp u-boot.img
$ sudo sync
$ sudo umount  /mnt

Now with that sdcard in BeagleBone the output from serial should be:

U-Boot SPL 2014.07-rc4-00264-g23f23f2-dirty (Jul 05 2014 - 21:56:58)
reading u-boot.img
reading u-boot.img


U-Boot 2014.07-rc4-00264-g23f23f2-dirty (Jul 05 2014 - 21:56:58)

I2C:   ready
DRAM:  512 MiB
NAND:  0 MiB
MMC:   OMAP SD/MMC: 0, OMAP SD/MMC: 1
*** Warning - readenv() failed, using default environment

Net:   <ethaddr> not set. Validating first E-fuse MAC
cpsw, usb_ether
Hit any key to stop autoboot:  0 
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
reading uEnv.txt
** Unable to read file uEnv.txt **
** Invalid partition 2 **
switch to partitions #0, OK
mmc1(part 0) is current device
SD/MMC found on device 1
reading uEnv.txt
26 bytes read in 3 ms (7.8 KiB/s)
Loaded environment from uEnv.txt
Importing environment from mmc ...
** File not found /boot/zImage **
Booting from nand ...

no devices available

no devices available
Bad Linux ARM zImage magic!
U-Boot# 

There are two problems in this output. First, you don't have a uEnv.txt, which configure the U-Boot and secondly you don't have a linux image.

Kernel

Mainline Kernel

You can use the mainline linux for beaglebone.

Get:

$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

Clean:

$ armmake distclean

Configure for BeagleBone:

$ armmake multi_v7_defconfig

Check if two remaining configs are set:

│ Symbol: MFD_TPS65217 [=n]
│ Type  : tristate
│ Prompt: TI TPS65217 Power Management / White LED chips
│   Location:
│     -> Device Drivers
│ (1)   -> Multifunction device drivers
│   Defined at drivers/mfd/Kconfig:877
│   Depends on: HAS_IOMEM [=y] && I2C [=y]
│   Selects: MFD_CORE [=y] && REGMAP_I2C [=y]

Build:

$ armmake

TODO

Test your new Kernel

TODO