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- #! /bin/sh
- # SPDX-License-Identifier: GPL-2.0
- # Copyright (c) 2020, Google LLC. All rights reserved.
- # Author: Saravana Kannan <saravanak@google.com>
- function help() {
- cat << EOF
- Usage: $(basename $0) [-c|-d|-m|-f] [filter options] <list of devices>
- This script needs to be run on the target device once it has booted to a
- shell.
- The script takes as input a list of one or more device directories under
- /sys/devices and then lists the probe dependency chain (suppliers and
- parents) of these devices. It does a breadth first search of the dependency
- chain, so the last entry in the output is close to the root of the
- dependency chain.
- By default it lists the full path to the devices under /sys/devices.
- It also takes an optional modifier flag as the first parameter to change
- what information is listed in the output. If the requested information is
- not available, the device name is printed.
- -c lists the compatible string of the dependencies
- -d lists the driver name of the dependencies that have probed
- -m lists the module name of the dependencies that have a module
- -f list the firmware node path of the dependencies
- -g list the dependencies as edges and nodes for graphviz
- -t list the dependencies as edges for tsort
- The filter options provide a way to filter out some dependencies:
- --allow-no-driver By default dependencies that don't have a driver
- attached are ignored. This is to avoid following
- device links to "class" devices that are created
- when the consumer probes (as in, not a probe
- dependency). If you want to follow these links
- anyway, use this flag.
- --exclude-devlinks Don't follow device links when tracking probe
- dependencies.
- --exclude-parents Don't follow parent devices when tracking probe
- dependencies.
- EOF
- }
- function dev_to_detail() {
- local i=0
- while [ $i -lt ${#OUT_LIST[@]} ]
- do
- local C=${OUT_LIST[i]}
- local S=${OUT_LIST[i+1]}
- local D="'$(detail_chosen $C $S)'"
- if [ ! -z "$D" ]
- then
- # This weirdness is needed to work with toybox when
- # using the -t option.
- printf '%05u\t%s\n' ${i} "$D" | tr -d \'
- fi
- i=$((i+2))
- done
- }
- function already_seen() {
- local i=0
- while [ $i -lt ${#OUT_LIST[@]} ]
- do
- if [ "$1" = "${OUT_LIST[$i]}" ]
- then
- # if-statement treats 0 (no-error) as true
- return 0
- fi
- i=$(($i+2))
- done
- # if-statement treats 1 (error) as false
- return 1
- }
- # Return 0 (no-error/true) if parent was added
- function add_parent() {
- if [ ${ALLOW_PARENTS} -eq 0 ]
- then
- return 1
- fi
- local CON=$1
- # $CON could be a symlink path. So, we need to find the real path and
- # then go up one level to find the real parent.
- local PARENT=$(realpath $CON/..)
- while [ ! -e ${PARENT}/driver ]
- do
- if [ "$PARENT" = "/sys/devices" ]
- then
- return 1
- fi
- PARENT=$(realpath $PARENT/..)
- done
- CONSUMERS+=($PARENT)
- OUT_LIST+=(${CON} ${PARENT})
- return 0
- }
- # Return 0 (no-error/true) if one or more suppliers were added
- function add_suppliers() {
- local CON=$1
- local RET=1
- if [ ${ALLOW_DEVLINKS} -eq 0 ]
- then
- return 1
- fi
- SUPPLIER_LINKS=$(ls -1d $CON/supplier:* 2>/dev/null)
- for SL in $SUPPLIER_LINKS;
- do
- SYNC_STATE=$(cat $SL/sync_state_only)
- # sync_state_only links are proxy dependencies.
- # They can also have cycles. So, don't follow them.
- if [ "$SYNC_STATE" != '0' ]
- then
- continue
- fi
- SUPPLIER=$(realpath $SL/supplier)
- if [ ! -e $SUPPLIER/driver -a ${ALLOW_NO_DRIVER} -eq 0 ]
- then
- continue
- fi
- CONSUMERS+=($SUPPLIER)
- OUT_LIST+=(${CON} ${SUPPLIER})
- RET=0
- done
- return $RET
- }
- function detail_compat() {
- f=$1/of_node/compatible
- if [ -e $f ]
- then
- echo -n $(cat $f)
- else
- echo -n $1
- fi
- }
- function detail_module() {
- f=$1/driver/module
- if [ -e $f ]
- then
- echo -n $(basename $(realpath $f))
- else
- echo -n $1
- fi
- }
- function detail_driver() {
- f=$1/driver
- if [ -e $f ]
- then
- echo -n $(basename $(realpath $f))
- else
- echo -n $1
- fi
- }
- function detail_fwnode() {
- f=$1/firmware_node
- if [ ! -e $f ]
- then
- f=$1/of_node
- fi
- if [ -e $f ]
- then
- echo -n $(realpath $f)
- else
- echo -n $1
- fi
- }
- function detail_graphviz() {
- if [ "$2" != "ROOT" ]
- then
- echo -n "\"$(basename $2)\"->\"$(basename $1)\""
- else
- echo -n "\"$(basename $1)\""
- fi
- }
- function detail_tsort() {
- echo -n "\"$2\" \"$1\""
- }
- function detail_device() { echo -n $1; }
- alias detail=detail_device
- ALLOW_NO_DRIVER=0
- ALLOW_DEVLINKS=1
- ALLOW_PARENTS=1
- while [ $# -gt 0 ]
- do
- ARG=$1
- case $ARG in
- --help)
- help
- exit 0
- ;;
- -c)
- alias detail=detail_compat
- ;;
- -m)
- alias detail=detail_module
- ;;
- -d)
- alias detail=detail_driver
- ;;
- -f)
- alias detail=detail_fwnode
- ;;
- -g)
- alias detail=detail_graphviz
- ;;
- -t)
- alias detail=detail_tsort
- ;;
- --allow-no-driver)
- ALLOW_NO_DRIVER=1
- ;;
- --exclude-devlinks)
- ALLOW_DEVLINKS=0
- ;;
- --exclude-parents)
- ALLOW_PARENTS=0
- ;;
- *)
- # Stop at the first argument that's not an option.
- break
- ;;
- esac
- shift
- done
- function detail_chosen() {
- detail $1 $2
- }
- if [ $# -eq 0 ]
- then
- help
- exit 1
- fi
- CONSUMERS=($@)
- OUT_LIST=()
- # Do a breadth first, non-recursive tracking of suppliers. The parent is also
- # considered a "supplier" as a device can't probe without its parent.
- i=0
- while [ $i -lt ${#CONSUMERS[@]} ]
- do
- CONSUMER=$(realpath ${CONSUMERS[$i]})
- i=$(($i+1))
- if already_seen ${CONSUMER}
- then
- continue
- fi
- # If this is not a device with a driver, we don't care about its
- # suppliers.
- if [ ! -e ${CONSUMER}/driver -a ${ALLOW_NO_DRIVER} -eq 0 ]
- then
- continue
- fi
- ROOT=1
- # Add suppliers to CONSUMERS list and output the consumer details.
- #
- # We don't need to worry about a cycle in the dependency chain causing
- # infinite loops. That's because the kernel doesn't allow cycles in
- # device links unless it's a sync_state_only device link. And we ignore
- # sync_state_only device links inside add_suppliers.
- if add_suppliers ${CONSUMER}
- then
- ROOT=0
- fi
- if add_parent ${CONSUMER}
- then
- ROOT=0
- fi
- if [ $ROOT -eq 1 ]
- then
- OUT_LIST+=(${CONSUMER} "ROOT")
- fi
- done
- # Can NOT combine sort and uniq using sort -suk2 because stable sort in toybox
- # isn't really stable.
- dev_to_detail | sort -k2 -k1 | uniq -f 1 | sort | cut -f2-
- exit 0
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