View source for Apc8750


== Installing Slackware on apc-8750 ==

Mainline linux kernel lacks support for Wondermedia 8750 currently. 
However linux-vtwm kernel available at github has support for Wondermedia 8750 SOC.
Since the kernel failed to load initrd cpio archive the normal way, a special method
was used for loading the setup image. 

* Create three partitions, first bootable vfat, second reiserfs and third Linux swap.
* Download and copy uzImage.bin and initrd-kirkwood.cpio to first vfat partition
* Download and copy Slackware installation files over to second partition
* Boot from the micro sd card prepared, install, and configure Slackware
* Download and replace the boot kernel with new uzImage.bin for booting from 
second partition.

== 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
 
             * uzImage.bin
                   [[Detailed description of how uzImage.bin was prepared.]]

             * initrd-kirkwood.cpio
                   [[Detailed description of how initrd-kirkwood.cpio was prepared.]]

Download and keep these files ready

=== Preparing the micro sd card ===

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

<pre>
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

</pre>

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

==== Detailed description of how Slackware install kernel was prepared. ====

I used linux-vtwm-testing available at https://github.com/linux-wmt/linux-vtwm
Zipfile you download from the site may cause problem when extracting - few files
may be missing!. One option is to use p7zip or other unzip program instead of the
default zip utility in Slackware. You may also get a tar.gz file using
<pre>
wget --no-check-certificate \
    https://github.com/linux-wmt/linux-vtwm/archive/testing.tar.gz
</pre>

Please refer to the link [[config.slackinstall.vga]] for the config file which was used. This method also require a small initramfs image prepared from the boot media available 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:
<pre>
        #!/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
</pre>

Copy the initramfs_data.cpio.gz for to $KERNEL_SRC/usr area.

===== Details of how initramfs_data.cpio.gz was prepared. =====

<pre>
gunzip initrd.gz
mkdir initramfs_data
mount -o loop initrd initramfs_data

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 )

</pre>

Please note that the kernel uses a CONFIG_CMDLINE=
for vga:
<pre>
CONFIG_CMDLINE=" mem=440M console=tty0 mbtotal=52M"
CONFIG_CMDLINE_FORCE=y
</pre>
for serial:
<pre>
CONFIG_CMDLINE=" mem=440M console=ttyWMT0,115200n8 mbtotal=52M"
CONFIG_CMDLINE_FORCE=y
</pre>
kernel is compiled on the host, using arm-2014.05 from arm.

kernel build procedure:
<pre>
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

</pre>
Preparing the cpio archive:

<pre>
        download http://ftp.arm.slackware.com/slackwarearm/slackwarearm-14.1/isolinux/uinitrd-kirkwood.img
        dd if=./uinitrd-kirkwood.img bs=64 skip=1 of=initrd-kirkwood.cpio.gz
        gunzip initrd-kirkwood.cpio.gz
</pre>

== Copying Slackware install files onto second 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, from  http://ftp.arm.slackware.com/slackwarearm/slackwarearm-14.1/

      sdc1:
                /uzImage.bin
                /initrd-kirkwood.cpio
      sdc2:
                /slackware14.1/

== Booting with the installer and installing Slackware ==

Now you are ready to boot the from the new disk just prepared, and install Slackware from the pre mounted directory under /mnt/slackware14.1/slackware ( which is automounted as the selection for target is done ). Put the newly prepared micro sd card in the slot and reboot apc-8750. Once you get the Slackware login prompt, proceed as usual.

=== Configuration ===

For X Windows, use a window manager like fluxbox.

== Post installation preparation ==

After the installation is done, you need to replace the kernel uzImage.bin with a new
one, this time with no initramfs_data.cpio.gz, and CONFIG_CMDLINE= changed for bootin from partition 2. 

<pre>
CONFIG_CMDLINE=" mem=460M root=/dev/mmcblk0p2 rootwait nonitrd ro console=tty0"
CONFIG_CMDLINE_FORCE=y
</pre>

For this, download uzImage.bin from here, and copy over
to the first partition ( bootable vfat one ). Once that is done reboot the machine once again, to get Slackware going!

=== Procedure used for preparing the Slackware boot kernel ===

Please refer to the link [[config.slackboot.vga]] for the config file which was used.
<pre>
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.slackboot.vga $OBJ/.config
rm $KERNEL_SRC/usr/initramfs_data.cpio.g

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

</pre>

Once Slackware is installed, and the  new uzImage.bin is copied over

    sdc1:
              /uzImage.bin
              /initrd-kirkwood.cpio  => not required anymore

    sdc2:

              /bin
              /boot
              /cdrom
              /dev/
              /etc/
              /home/
              /proc/
              /slackware14.1  => not required anymore
              /usr/
              /var/

You may remove files which are not required anymore, and free up some space. Once that is done, reboot apc-8750. 
== links ==

http://apc.io/products/8750a/

http://apc.io/library/

https://github.com/linux-wmt/linux-vtwm

http://arm.slackware.com/getslack/

http://ftp.arm.slackware.com/slackwarearm/

http://sourceforge.net/projects/slackwareonapc8750/files/

http://sourceforge.net/projects/slackwareonapc8750/files/initrd-kirkwood.cpio.gz/download

http://sourceforge.net/projects/slackwareonapc8750/files/install/vga/uzImage.bin/download

http://sourceforge.net/projects/slackwareonapc8750/files/boot/vga/uzImage.bin/download

http://sourceforge.net/projects/slackwareonapc8750/files/configs/config.slackinst.vga/download

http://sourceforge.net/projects/slackwareonapc8750/files/configs/config.slackboot.vga/download

http://sourceforge.net/projects/slackwareonapc8750/files/configs/config.slackinst.ttyWMT0/download

http://sourceforge.net/projects/slackwareonapc8750/files/configs/config.slackboot.ttyWMT0/download

http://sourceforge.net/projects/slackwareonapc8750/files/initramfs_data.cpio.gz/download