Chris at 09:03, 14 July 2007

2007-07-14T09:03:50Z

RBot: Bot (Edward's framework)

2007-03-07T03:32:33Z

Bot (Edward's framework)

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Skyeye is an open-source ARM emulator with a GDB stub, allowing you to use GDB to debug code running within the emulator.

Skyeye can be obtained at: [http://gro.clinux.org/projects/skyeye/ gro.clinux.org/projects/skyeye/]

All files are at: http://www.bradgoodman.com/skyeye The patch for skyeye-v1 is here: http://www.bradgoodman.com/skyeye/bkg_skyeye.patch (It's a little messy - i.e. adding a bunch of lines that are commented out - but I'll clean it up later.) The patch fixes a few things:

## Allows halfword and word read to 32-bit I/O ports via GDB (instead of 4 individual byte reads - which are not the same thing)
## Fixes in UART FIFO status registers which were not implemented and would break Linux S3C44B0X serial driver.
## Internal Interrupt status bits were not actually updated when things like the interrupt mask registers were modified - breaking interrupt suport.
My skyeye.conf file is here: http://www.bradgoodman.com/skyeye/skyeye.conf Note the memory images:

<pre>
mem_bank: map=M, type=RW, addr=0x00000000, size=0x00400000, file=newboot.rom
mem_bank: map=I, type=RW, addr=0x01c00000, size=0x00400000 mem_bank: map=M, type=RW, addr=0x0c000000, size=0x00400000, file=./linux</pre>

The file "newboot.rom" is a slightly modified version of the [[JuiceBox]] ROM file from emsoft's web site (boot.rom). It is actually importiant to have this loaded, because the ARM boot and (more important) interrupt vectors are down in this area (0x000000) - and point up to your installed kernel - the "./linux" file at 0xc000000.

(My linux and newboot.rom are included)

The Linux kernel I built was also from emsoft's web site - using the arm-elf-tools-20030314.sh toolchain to build it.

Also, the [[RAMdisk]] is in this image too - a ROMFS filesystem at address 0x100000 (0x10000 offset in this ROM file.)

The "slight modification" to the boot.rom is in the /etc/rc file in the [[RAMdisk]]. I added a command here to launch a shell /bin/sh:

<pre>
/bin/sh < /dev/ttyS0 > /dev/ttyS0</pre>

To modify the ROMFS filesystem within the ROM image, you need to do a couple things:

# Get genromfs off of [[Source Forge]]

2. Yank the ROMFS image out of the boot.rom. Remember, this starts at offset 0x100000 from the file - so you can do this with:

<pre>
dd if=boot.rom of=romfs.img bs=1024 skip=1024</pre>

(Note: For all you Dee-Dee-Dee types, 1024*1024=0x100000)

3. Mount the ROMFS filesytem: mount -t romfs romfs.img /mnt

4. Make your modifications to the filesytem, then use genfromfs to re-create it.

'''NOTE'''when you unpackage the ROMFS filesystem, all of the links become "normal" files. Since most of the stuff in the /bin directory (and maybe /sbin?) are links to /bin/busybox - this will make it a whopping 16M ROMFS image. To fix this, you're going to want to copy the old filesystem image (cp -ax /mnt /newdir). Then, find all the files in the /bin directory which as the same size as /bin/busybox, delete them, and make them symlinks to busybox. Then use *this* directory to rom genromfs on.

<pre>
genromfs -a 16 -f newimage.img -d /newdir</pre>

5. Then put this image back into the ROM - copying it back to the 0x100000 offset of the file:

<pre>
dd if=newimage.img of=newboot.rom bs=1024 seek=1024</pre>

{myfirstname}@bradgoodman.com

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JuiceBox Emulator - Revision history

Chris at 09:03, 14 July 2007

RBot: Bot (Edward's framework)