Apc8750

Trial Edition

Installing Slackware on apc-8750

Creating a bootable micro sd card

For this you need a custom built kernel and a initramfs image from slackware for arm distribution - uinitrd-kirkwood.img

Preparing the micro sd card

You need at least three partitions, one vfat, one or more Linux partitions, and a Linux swap partition. Here is how the partitions I used look like under fdisk ran on host.

Disk /dev/sdc: 15.9 GB, 15931539456 bytes
64 heads, 32 sectors/track, 15193 cylinders, total 31116288 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: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1   *        2048      206847      102400    c  W95 FAT32 (LBA)
/dev/sdc2          206848    28878847    14336000   83  Linux
/dev/sdc3        28878848    31116287     1118720   82  Linux swap

Creating filesystem:

1st partition: make it bootable, and create a file system using mkfs.vfat
2nd partition: create a reiserfs ( or other ) file system using mkreiserfs

Now you need to make a custom kernel for booting into. I used linux-vtwm-testing available at https://github.com/linux-wmt/linux-vtwm Please refer to the link: for the config file which was used. also require a small initramfs image prepared from the boot media aviable at apc.io library. download it from here : initramfs_data.cpio.gz or use the following init scrip with the initrd.gz from apc.io library.

init:

        #!/bin/busybox sh
        /bin/busybox mount -t proc /proc
        /bin/busybox mount -t sys /sys
        /bin/busybox echo /sbin/mdev > /proc/sys/kernel/hotplug
        /bin/busybox mdev -s
        /bin/busybox --install
        mkfs.ext2 /dev/ram0
        mkdir /root
        mount /dev/ram0 /root
        cd /root
        mkdir /flash
        mount /dev/mmcblk0p1 /flash
        cpio -id < /flash/initrd-kirkwood.cpio
        exec chroot /root /bin/busybox init
        exec /bin/busybox init

Copy the initramfs_data.cpio.gz for to $KERNEL_SRC/usr area. In case you are building it on your own:

gunzip initrd.gz
mkdir initramfs_dat
mountpoint initramfs_data || mount -o loop initrd fs
create initramfs_data/init as shown above
chmod a+x initramfs_data/init
sync
(cd initramfs_data ; find . | cpio -o -H newc | gzip  > ../initramfs_data.cpio.gz )

Please note that the kernel uses a CONFIG_CMDLINE= for vga:

CONFIG_CMDLINE=" mem=440M console=tty0 mbtotal=52M"

for serial:

CONFIG_CMDLINE=" mem=440M console=ttyWMT0,115200n8 mbtotal=52M"

kernel is compiled on the host, using arm-2014.05 from arm.

Eg:

export OBJ=/src/apc.io/obj.testing
export KERNEL_SRC=/src/apc.io/linux-vtwm-testing
export PATH=~/apc.io/apc-8750-master/u-boot/tools:$PATH
export PATH=/opt/local/arm/arm-2014.05/bin:$PATH
cp config.slackinst.vga $OBJ/.config
cp initramfs_data.cpio.gz $KERNEL_SRC/usr

make -C $KERNEL_SRC O=$OBJ ARCH=arm CROSS_COMPILE=arm-none-eabi- zImage -j 3
mv $OBJ/arch/arm/boot/zImage $1/$2/ ;
make -C $KERNEL_SRC O=$OBJ ARCH=arm CROSS_COMPILE=arm-none-eabi- dtbs
cat $1/$2/zImage $OBJ/arch/arm/boot/dts/wm8750-apc8750.dtb > $1/$2/zImage_w_dtb
mkimage -A arm -O linux -T kernel -C none -a 0x8000 \
     -e 0x8000 -n "My Linux" -d $1/$2/zImage_w_dtb $1/$2/uzImage.bin

Preparing the cpio archive:

        dd if=./uinitrd-kirkwood.img bs=64 skip=1 of=initrd-kirkwood.cpio.gz
        gunzip initrd-kirkwood.cpio.gz

Once both uzImage.bin and initrd-kirkwood.cpio copy them to the bootable vfat partition.

Create a slackware14.1 directory in the reiserfs partition of the micro sd card. Copy slackware for arm distribution to the slackware14.1 directory. Now you are ready to boot the new disk, and install slackware from the pre mounted directory under /mnt/slackware14.1/slackware ( which is automounted as the selection for target is done ).