gsc: gsc_direct_mem.sh

#!/bin/bash

[ "$#" -ne 2 ] && {
        echo "This script acts as a wrapper around I2C commands in order to do direct memory reads of the GSC."
        echo "It will output the i2c response in an i2cdump type format."
        echo
        echo "Usage: $0 <offset> <length>"
        echo
        echo "Example usage to read all 2000(0x7d0) peripheral register values:"
        echo "  $0 0x100 0x7d0"
        exit 1
}

# Store inputs
BUS=0
ADDR=0x5e
OFFSET=$1
LENGTH=$2

# Misc variables
COUNT=0
PAGE=0
PRINTVAL=0x0000
REMAINDER=0
HIGH=
RETURN=

# Calculate initial page number based on passed in offset
PAGE=$((OFFSET / 0x100))
OFFSET=$((OFFSET % 0x100))

echo "      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f     0123456789abcdef"
while [[ $COUNT -ne $LENGTH ]]; do
        # Set the page number accordingly
        i2cset -f -y 0 0x20 0x16 $PAGE

        # Do either a full i2cdump or specify a range if bytes aren't a 0x100 aligned block
        if [[ $(($LENGTH - $COUNT)) -lt 0x100 || $OFFSET -ne 0 ]]; then
                HIGH=$(($LENGTH - $COUNT - 1 + $OFFSET))
                # Record remainder for i2c 0x100 upper range limit
                if [[ $HIGH -gt 0x100 ]]; then
                        REMAINDER=$(($HIGH + 1 - 0x100))
                else
                        REMAINDER=0
                fi

                RETURN=$(i2cdump -f -y -r ${OFFSET}-$(($HIGH - $REMAINDER)) 0 $ADDR b | grep ':')
                COUNT=$(($HIGH - $REMAINDER - $OFFSET + 1 + $COUNT))
                OFFSET=0
        else
                RETURN=$(i2cdump -f -y 0 $ADDR b | grep ':')
                COUNT=$(($COUNT + 0x100))
        fi

        if [[ "$RETURN" ]]; then # Only print reads
                # Format output to be continuous and account for page increase
                echo "$RETURN" | while read x; do
                        printf "%04x" "$((0x$(echo $x | cut -d':' -f1) + $((PAGE * 0x100))))"
                        echo ":${x##*:}"
                done
        fi

        # Increase the page count
        ((++PAGE))
done