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| -rw-r--r-- | MAINTAINERS | 6 | ||||
| -rwxr-xr-x | scripts/dev-needs.sh | 315 |
2 files changed, 321 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index f0068bceeb61..4e4d9e3f9986 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -4994,6 +4994,12 @@ S: Maintained F: drivers/base/devcoredump.c F: include/linux/devcoredump.h +DEVICE DEPENDENCY HELPER SCRIPT +M: Saravana Kannan <saravanak@google.com> +L: linux-kernel@vger.kernel.org +S: Maintained +F: scripts/dev-needs.sh + DEVICE DIRECT ACCESS (DAX) M: Dan Williams <dan.j.williams@intel.com> M: Vishal Verma <vishal.l.verma@intel.com> diff --git a/scripts/dev-needs.sh b/scripts/dev-needs.sh new file mode 100755 index 000000000000..454cc304fb44 --- /dev/null +++ b/scripts/dev-needs.sh @@ -0,0 +1,315 @@ +#! /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 |