scripts/dev-needs.sh

   1 #! /bin/sh
   2 # SPDX-License-Identifier: GPL-2.0
   3 # Copyright (c) 2020, Google LLC. All rights reserved.
   4 # Author: Saravana Kannan <saravanak@google.com>
   5
   6 function help() {
   7         cat << EOF
   8 Usage: $(basename $0) [-c|-d|-m|-f] [filter options] <list of devices>
   9
  10 This script needs to be run on the target device once it has booted to a
  11 shell.
  12
  13 The script takes as input a list of one or more device directories under
  14 /sys/devices and then lists the probe dependency chain (suppliers and
  15 parents) of these devices. It does a breadth first search of the dependency
  16 chain, so the last entry in the output is close to the root of the
  17 dependency chain.
  18
  19 By default it lists the full path to the devices under /sys/devices.
  20
  21 It also takes an optional modifier flag as the first parameter to change
  22 what information is listed in the output. If the requested information is
  23 not available, the device name is printed.
  24
  25   -c    lists the compatible string of the dependencies
  26   -d    lists the driver name of the dependencies that have probed
  27   -m    lists the module name of the dependencies that have a module
  28   -f    list the firmware node path of the dependencies
  29   -g    list the dependencies as edges and nodes for graphviz
  30   -t    list the dependencies as edges for tsort
  31
  32 The filter options provide a way to filter out some dependencies:
  33   --allow-no-driver     By default dependencies that don't have a driver
  34                         attached are ignored. This is to avoid following
  35                         device links to "class" devices that are created
  36                         when the consumer probes (as in, not a probe
  37                         dependency). If you want to follow these links
  38                         anyway, use this flag.
  39
  40   --exclude-devlinks    Don't follow device links when tracking probe
  41                         dependencies.
  42
  43   --exclude-parents     Don't follow parent devices when tracking probe
  44                         dependencies.
  45
  46 EOF
  47 }
  48
  49 function dev_to_detail() {
  50         local i=0
  51         while [ $i -lt ${#OUT_LIST[@]} ]
  52         do
  53                 local C=${OUT_LIST[i]}
  54                 local S=${OUT_LIST[i+1]}
  55                 local D="'$(detail_chosen $C $S)'"
  56                 if [ ! -z "$D" ]
  57                 then
  58                         # This weirdness is needed to work with toybox when
  59                         # using the -t option.
  60                         printf '%05u\t%s\n' ${i} "$D" | tr -d \'
  61                 fi
  62                 i=$((i+2))
  63         done
  64 }
  65
  66 function already_seen() {
  67         local i=0
  68         while [ $i -lt ${#OUT_LIST[@]} ]
  69         do
  70                 if [ "$1" = "${OUT_LIST[$i]}" ]
  71                 then
  72                         # if-statement treats 0 (no-error) as true
  73                         return 0
  74                 fi
  75                 i=$(($i+2))
  76         done
  77
  78         # if-statement treats 1 (error) as false
  79         return 1
  80 }
  81
  82 # Return 0 (no-error/true) if parent was added
  83 function add_parent() {
  84
  85         if [ ${ALLOW_PARENTS} -eq 0 ]
  86         then
  87                 return 1
  88         fi
  89
  90         local CON=$1
  91         # $CON could be a symlink path. So, we need to find the real path and
  92         # then go up one level to find the real parent.
  93         local PARENT=$(realpath $CON/..)
  94
  95         while [ ! -e ${PARENT}/driver ]
  96         do
  97                 if [ "$PARENT" = "/sys/devices" ]
  98                 then
  99                         return 1
 100                 fi
 101                 PARENT=$(realpath $PARENT/..)
 102         done
 103
 104         CONSUMERS+=($PARENT)
 105         OUT_LIST+=(${CON} ${PARENT})
 106         return 0
 107 }
 108
 109 # Return 0 (no-error/true) if one or more suppliers were added
 110 function add_suppliers() {
 111         local CON=$1
 112         local RET=1
 113
 114         if [ ${ALLOW_DEVLINKS} -eq 0 ]
 115         then
 116                 return 1
 117         fi
 118
 119         SUPPLIER_LINKS=$(ls -1d $CON/supplier:* 2>/dev/null)
 120         for SL in $SUPPLIER_LINKS;
 121         do
 122                 SYNC_STATE=$(cat $SL/sync_state_only)
 123
 124                 # sync_state_only links are proxy dependencies.
 125                 # They can also have cycles. So, don't follow them.
 126                 if [ "$SYNC_STATE" != '0' ]
 127                 then
 128                         continue
 129                 fi
 130
 131                 SUPPLIER=$(realpath $SL/supplier)
 132
 133                 if [ ! -e $SUPPLIER/driver -a ${ALLOW_NO_DRIVER} -eq 0 ]
 134                 then
 135                         continue
 136                 fi
 137
 138                 CONSUMERS+=($SUPPLIER)
 139                 OUT_LIST+=(${CON} ${SUPPLIER})
 140                 RET=0
 141         done
 142
 143         return $RET
 144 }
 145
 146 function detail_compat() {
 147         f=$1/of_node/compatible
 148         if [ -e $f ]
 149         then
 150                 echo -n $(cat $f)
 151         else
 152                 echo -n $1
 153         fi
 154 }
 155
 156 function detail_module() {
 157         f=$1/driver/module
 158         if [ -e $f ]
 159         then
 160                 echo -n $(basename $(realpath $f))
 161         else
 162                 echo -n $1
 163         fi
 164 }
 165
 166 function detail_driver() {
 167         f=$1/driver
 168         if [ -e $f ]
 169         then
 170                 echo -n $(basename $(realpath $f))
 171         else
 172                 echo -n $1
 173         fi
 174 }
 175
 176 function detail_fwnode() {
 177         f=$1/firmware_node
 178         if [ ! -e $f ]
 179         then
 180                 f=$1/of_node
 181         fi
 182
 183         if [ -e $f ]
 184         then
 185                 echo -n $(realpath $f)
 186         else
 187                 echo -n $1
 188         fi
 189 }
 190
 191 function detail_graphviz() {
 192         if [ "$2" != "ROOT" ]
 193         then
 194                 echo -n "\"$(basename $2)\"->\"$(basename $1)\""
 195         else
 196                 echo -n "\"$(basename $1)\""
 197         fi
 198 }
 199
 200 function detail_tsort() {
 201         echo -n "\"$2\" \"$1\""
 202 }
 203
 204 function detail_device() { echo -n $1; }
 205
 206 alias detail=detail_device
 207 ALLOW_NO_DRIVER=0
 208 ALLOW_DEVLINKS=1
 209 ALLOW_PARENTS=1
 210
 211 while [ $# -gt 0 ]
 212 do
 213         ARG=$1
 214         case $ARG in
 215                 --help)
 216                         help
 217                         exit 0
 218                         ;;
 219                 -c)
 220                         alias detail=detail_compat
 221                         ;;
 222                 -m)
 223                         alias detail=detail_module
 224                         ;;
 225                 -d)
 226                         alias detail=detail_driver
 227                         ;;
 228                 -f)
 229                         alias detail=detail_fwnode
 230                         ;;
 231                 -g)
 232                         alias detail=detail_graphviz
 233                         ;;
 234                 -t)
 235                         alias detail=detail_tsort
 236                         ;;
 237                 --allow-no-driver)
 238                         ALLOW_NO_DRIVER=1
 239                         ;;
 240                 --exclude-devlinks)
 241                         ALLOW_DEVLINKS=0
 242                         ;;
 243                 --exclude-parents)
 244                         ALLOW_PARENTS=0
 245                         ;;
 246                 *)
 247                         # Stop at the first argument that's not an option.
 248                         break
 249                         ;;
 250         esac
 251         shift
 252 done
 253
 254 function detail_chosen() {
 255         detail $1 $2
 256 }
 257
 258 if [ $# -eq 0 ]
 259 then
 260         help
 261         exit 1
 262 fi
 263
 264 CONSUMERS=($@)
 265 OUT_LIST=()
 266
 267 # Do a breadth first, non-recursive tracking of suppliers. The parent is also
 268 # considered a "supplier" as a device can't probe without its parent.
 269 i=0
 270 while [ $i -lt ${#CONSUMERS[@]} ]
 271 do
 272         CONSUMER=$(realpath ${CONSUMERS[$i]})
 273         i=$(($i+1))
 274
 275         if already_seen ${CONSUMER}
 276         then
 277                 continue
 278         fi
 279
 280         # If this is not a device with a driver, we don't care about its
 281         # suppliers.
 282         if [ ! -e ${CONSUMER}/driver -a ${ALLOW_NO_DRIVER} -eq 0 ]
 283         then
 284                 continue
 285         fi
 286
 287         ROOT=1
 288
 289         # Add suppliers to CONSUMERS list and output the consumer details.
 290         #
 291         # We don't need to worry about a cycle in the dependency chain causing
 292         # infinite loops. That's because the kernel doesn't allow cycles in
 293         # device links unless it's a sync_state_only device link. And we ignore
 294         # sync_state_only device links inside add_suppliers.
 295         if add_suppliers ${CONSUMER}
 296         then
 297                 ROOT=0
 298         fi
 299
 300         if add_parent ${CONSUMER}
 301         then
 302                 ROOT=0
 303         fi
 304
 305         if [ $ROOT -eq 1 ]
 306         then
 307                 OUT_LIST+=(${CONSUMER} "ROOT")
 308         fi
 309 done
 310
 311 # Can NOT combine sort and uniq using sort -suk2 because stable sort in toybox
 312 # isn't really stable.
 313 dev_to_detail | sort -k2 -k1 | uniq -f 1 | sort | cut -f2-
 314
 315 exit 0