Hello everyone! I'm trying to get the usb_host_msc example to run on the Beaglebone Black. The example works fine until I try to issue the ls, cat or cd commands. Any of those end up triggering a Data Abort exception somewhere inside the disk_status function. Since StarterWare simply places an endless loop as a Data Abort handler, I wrote a small function which examines the instructions around the one pointed at by LR and prints their opcodes using ConsoleUtilsPrintf. The results were surprising: the instruction pointed at by LR, as well as the 3 instructions that preceeded it showed junk opcodes, and so did the 7 or so that followed it.
I'm compiling with the Linaro gcc-arm-none-eabi-4_7-2012q4 recommended by the Wiki and the project Makefiles. I'm recording the app binaries into an SD card and booting using U-Boot. Here's the script I'm using for preparing the SD card (it was originally written by Ben Gras to record RTEMS executables):
# we store all generated files here.
TMP_BASE_NAME=tmp_sdcard_dir
TMPDIR=$TMP_BASE_NAME.$$
FATIMG=$TMPDIR/bbxm_boot_fat.img
OFFSET=2048
FATSIZE_KB=2880
FATSIZE=`expr $FATSIZE_KB \* 2`
SIZE=`expr $FATSIZE + $OFFSET`
UENV=uEnv.txt
rm -rf $TMPDIR
mkdir -p $TMPDIR
if [ $# -ne 2 ]
then echo "Usage: $0 <executable> <image name>"
exit 1
fi
executable=$1
app=app.img
if [ ! -f "$executable" ]
then echo "Expecting executable as arg; $executable not found."
exit 1
fi
set -e
IMG=$2
# Make an empty image
dd if=/dev/zero of=$IMG bs=512 seek=$SIZE count=1
# Make an ms-dos FS image
rm -f $FATIMG
export MTOOLSRC=$TMPDIR/mtools-conf
echo "drive a:
file=\"$FATIMG\"
fat_bits=16
" >$MTOOLSRC
mformat -C -f $FATSIZE_KB a:
# Prepare the executable.
base=`basename $executable`
arm-none-eabi-objcopy $executable -O binary $TMPDIR/$base.bin
gzip -9 $TMPDIR/$base.bin
mkimage -A arm -T standalone -a 0x80000000 -e 0x80000000 -n APP -d $TMPDIR/$base.bin.gz $TMPDIR/$app
echo "setenv bootdelay 5
uenvcmd=run boot
boot=fatload mmc 0 0x80800000 $app ; bootm 0x80800000" >$TMPDIR/$UENV
# Copy the uboot and app image onto the FAT image
mcopy -bsp -i $FATIMG $MLO_PATH/MLO ::MLO
mcopy -bsp -i $FATIMG $UBOOT_PATH/u-boot.img ::u-boot.img
mcopy -bsp -i $FATIMG $TMPDIR/$app ::$app
mcopy -bsp -i $FATIMG $TMPDIR/$UENV ::$UENV
# Just a single FAT partition (type C) that uses all of the image
partition $IMG $OFFSET 'c:0*+'
# Put the FAT image into the SD image
dd if=$FATIMG of=$IMG seek=$OFFSET
# cleanup
rm -rf $TMP_BASE_NAME.*
echo "Result is in $IMG."
I finish by recording the resulting image to the SD card using dd.
Now, the weird thing is that this only happens with Rev. C boards. I tried doing this on a Rev A5C and got a Prefetch Abort inside U-Boot.
Any help would be appreciated. Thanks a lot!
