June 16, 2004

Curt Brune <curt@cucy.com>
http://www.cucy.com/

The 4510B product adds support for the ARM7tdmi-based Samsung S3C4510B
CPU and the EVB4510 evaluation board from ESPD Inc., which is based on
the Samsung part.  A description of the board is available from ESPD's
web site:

http://www.espd-inc.com/prod01-arm-samsung4510.htm

The makefile generates two binary files:

  image/romfs.img   -- the ROMFS binary image
  image/image.bin   -- the Linux binary image

I use the u-boot boot loader to load these images and to provide the
default command line.  The u-boot installation provides the "mkimage"
utility for packaging the binary images.  I run mkimage as follows to
package linux.bin and romfs.img -- note that I'm specifying to load
the romfs.img just after the BSS, rounded to an 8KB boundary:

     BSS_ADDR=`tail -1 linux-2.6.x/System.map`
     RD_ADDR=`set -- ${BSS_ADDR} ; echo 0x${1}`
     # align to 8KB
     RD_ADDR=`printf 0x%08x $(( RD_ADDR + (8*1024) - (RD_ADDR % (8*1024)) ))`
     
     mkimage -A arm -O linux -T kernel -C none \
         -a 0x8000 -e 0x8000 -n "Linux 2.6.6-hcs0 Kernel Image" \
         -d linux.bin uImage.bin
     
     mkimage -A arm -O linux -T ramdisk -C none \
        -a ${RD_ADDR} -n "ROMFS Image" \
        -d romfs.img uImage.romfs

U-Boot is nice because it figures out the appropriate Linux command
line arguments to load the initrd correctly.  Set the u-boot
"bootargs" environment variable to "root=/dev/ram0 keepinitrd" and you
are in business.  Below I load the uImage files using TFTP and boot:

>>  evb4510 # tftp 100000 uImage.bin
>>  TFTP from server 10.0.0.1; our IP address is 10.0.0.11
>>  Filename 'uImage.bin'.
>>  Load address: 0x100000
>>  Loading: #################################################################
>>  	 #################################################################
>>  	 #################################################################
>>  	 ##############################################
>>  done
>>  Bytes transferred = 1232252 (12cd7c hex)
>>  evb4510 # tftp 600000 uImage.romfs
>>  TFTP from server 10.0.0.1; our IP address is 10.0.0.11
>>  Filename 'uImage.romfs'.
>>  Load address: 0x600000
>>  Loading: #################################################################
>>  	 #################################################################
>>  	 ###################################
>>  done
>>  Bytes transferred = 841792 (cd840 hex)
>>  evb4510 # bootm 100000 600000
>>  ## Booting image at 00100000 ...
>>     Image Name:   Linux 2.6.6-hcs0 Kernel Image
>>     Image Type:   ARM Linux Kernel Image (uncompressed)
>>     Data Size:    1232188 Bytes =  1.2 MB
>>     Load Address: 00008000
>>     Entry Point:  00008000
>>     Verifying Checksum ... OK
>>  OK
>>  ## Loading Ramdisk Image at 00600000 ...
>>     Image Name:   ROMFS Image
>>     Image Type:   ARM Linux RAMDisk Image (uncompressed)
>>     Data Size:    841728 Bytes = 822 kB
>>     Load Address: 00144000
>>     Entry Point:  00144000
>>     Verifying Checksum ... OK
>>  
>>  Starting kernel ...
>>  
>>  Linux version 2.6.6-hsc0 (curt@hongkong) (gcc version 2.95.3 20010315 (release)(ColdFire patches - 20010318 from http://fiddes.net/coldfire/)(uClinux XIP and shared lib patches from http://www.snapgear.com/)) #2 Thu Jun 17 13:30:57 PDT 2004
>>  CPU: Samsung-S3C4510B [36807001] revision 1 (ARMv4T)
>>  Machine: ESPD 4510B(S3C4510B)
>>  

If you do not use u-boot you will need to compile a default command
line into your linux image.  A suitable command line would be:

root=/dev/ram0 initrd=0x00200000,900K keepinitrd

By default the kernel uses 1024KB ramdisks -- if your romfs.img is
larger than that you need to increase the size of your ramdisks.

Happy hacking!