tools/gpio/gpio-sloppy-logic-analyzer.sh

   1 #!/bin/sh -eu
   2 # SPDX-License-Identifier: GPL-2.0
   3 #
   4 # Helper script for the Linux Kernel GPIO sloppy logic analyzer
   5 #
   6 # Copyright (C) Wolfram Sang <wsa@sang-engineering.com>
   7 # Copyright (C) Renesas Electronics Corporation
   8
   9 samplefreq=1000000
  10 numsamples=250000
  11 cpusetdefaultdir='/sys/fs/cgroup'
  12 cpusetprefix='cpuset.'
  13 debugdir='/sys/kernel/debug'
  14 ladirname='gpio-sloppy-logic-analyzer'
  15 outputdir="$PWD"
  16 neededcmds='taskset zip'
  17 max_chans=8
  18 duration=
  19 initcpu=
  20 listinstances=0
  21 lainstance=
  22 lasysfsdir=
  23 triggerdat=
  24 trigger_bindat=
  25 progname="${0##*/}"
  26 print_help()
  27 {
  28         cat << EOF
  29 $progname - helper script for the Linux Kernel Sloppy GPIO Logic Analyzer
  30 Available options:
  31         -c|--cpu <n>: which CPU to isolate for sampling. Only needed once. Default <1>.
  32                       Remember that a more powerful CPU gives you higher sampling speeds.
  33                       Also CPU0 is not recommended as it usually does extra bookkeeping.
  34         -d|--duration-us <SI-n>: number of microseconds to sample. Overrides -n, no default value.
  35         -h|--help: print this help
  36         -i|--instance <str>: name of the logic analyzer in case you have multiple instances. Default
  37                              to first instance found
  38         -k|--kernel-debug-dir <str>: path to the kernel debugfs mountpoint. Default: <$debugdir>
  39         -l|--list-instances: list all available instances
  40         -n|--num_samples <SI-n>: number of samples to acquire. Default <$numsamples>
  41         -o|--output-dir <str>: directory to put the result files. Default: current dir
  42         -s|--sample_freq <SI-n>: desired sampling frequency. Might be capped if too large.
  43                                  Default: <1000000>
  44         -t|--trigger <str>: pattern to use as trigger. <str> consists of two-char pairs. First
  45                             char is channel number starting at "1". Second char is trigger level:
  46                             "L" - low; "H" - high; "R" - rising; "F" - falling
  47                             These pairs can be combined with "+", so "1H+2F" triggers when probe 1
  48                             is high while probe 2 has a falling edge. You can have multiple triggers
  49                             combined with ",". So, "1H+2F,1H+2R" is like the example before but it
  50                             waits for a rising edge on probe 2 while probe 1 is still high after the
  51                             first trigger has been met.
  52                             Trigger data will only be used for the next capture and then be erased.
  53
  54 <SI-n> is an integer value where SI units "T", "G", "M", "K" are recognized, e.g. '1M500K' is 1500000.
  55
  56 Examples:
  57 Samples $numsamples values at 1MHz with an already prepared CPU or automatically prepares CPU1 if needed,
  58 use the first logic analyzer instance found:
  59         '$progname'
  60 Samples 50us at 2MHz waiting for a falling edge on channel 2. CPU and instance as above:
  61         '$progname -d 50 -s 2M -t "2F"'
  62
  63 Note that the process exits after checking all parameters but a sub-process still works in
  64 the background. The result is only available once the sub-process finishes.
  65
  66 Result is a .sr file to be consumed with PulseView from the free Sigrok project. It is
  67 a zip file which also contains the binary sample data which may be consumed by others.
  68 The filename is the logic analyzer instance name plus a since-epoch timestamp.
  69 EOF
  70 }
  71
  72 fail()
  73 {
  74         echo "$1"
  75         exit 1
  76 }
  77
  78 parse_si()
  79 {
  80         conv_si="$(printf $1 | sed 's/[tT]+\?/*1000G+/g; s/[gG]+\?/*1000M+/g; s/[mM]+\?/*1000K+/g; s/[kK]+\?/*1000+/g; s/+$//')"
  81         si_val="$((conv_si))"
  82 }
  83 set_newmask()
  84 {
  85         for f in $(find "$1" -iname "$2"); do echo "$newmask" > "$f" 2>/dev/null || true; done
  86 }
  87
  88 init_cpu()
  89 {
  90         isol_cpu="$1"
  91
  92         [ -d "$lacpusetdir" ] || mkdir "$lacpusetdir"
  93
  94         cur_cpu=$(cat "${lacpusetfile}cpus")
  95         [ "$cur_cpu" = "$isol_cpu" ] && return
  96         [ -z "$cur_cpu" ] || fail "CPU$isol_cpu requested but CPU$cur_cpu already isolated"
  97
  98         echo "$isol_cpu" > "${lacpusetfile}cpus" || fail "Could not isolate CPU$isol_cpu. Does it exist?"
  99         echo 1 > "${lacpusetfile}cpu_exclusive"
 100         echo 0 > "${lacpusetfile}mems"
 101
 102         oldmask=$(cat /proc/irq/default_smp_affinity)
 103         newmask=$(printf "%x" $((0x$oldmask & ~(1 << isol_cpu))))
 104
 105         set_newmask '/proc/irq' '*smp_affinity'
 106         set_newmask '/sys/devices/virtual/workqueue/' 'cpumask'
 107
 108         # Move tasks away from isolated CPU
 109         for p in $(ps -o pid | tail -n +2); do
 110                 mask=$(taskset -p "$p") || continue
 111                 # Ignore tasks with a custom mask, i.e. not equal $oldmask
 112                 [ "${mask##*: }" = "$oldmask" ] || continue
 113                 taskset -p "$newmask" "$p" || continue
 114         done 2>/dev/null >/dev/null
 115
 116         # Big hammer! Working with 'rcu_momentary_eqs()' for a more fine-grained solution
 117         # still printed warnings. Same for re-enabling the stall detector after sampling.
 118         echo 1 > /sys/module/rcupdate/parameters/rcu_cpu_stall_suppress
 119
 120         cpufreqgov="/sys/devices/system/cpu/cpu$isol_cpu/cpufreq/scaling_governor"
 121         [ -w "$cpufreqgov" ] && echo 'performance' > "$cpufreqgov" || true
 122 }
 123
 124 parse_triggerdat()
 125 {
 126         oldifs="$IFS"
 127         IFS=','; for trig in $1; do
 128                 mask=0; val1=0; val2=0
 129                 IFS='+'; for elem in $trig; do
 130                         chan=${elem%[lhfrLHFR]}
 131                         mode=${elem#$chan}
 132                         # Check if we could parse something and the channel number fits
 133                         [ "$chan" != "$elem" ] && [ "$chan" -le $max_chans ] || fail "Trigger syntax error: $elem"
 134                         bit=$((1 << (chan - 1)))
 135                         mask=$((mask | bit))
 136                         case $mode in
 137                                 [hH]) val1=$((val1 | bit)); val2=$((val2 | bit));;
 138                                 [fF]) val1=$((val1 | bit));;
 139                                 [rR]) val2=$((val2 | bit));;
 140                         esac
 141                 done
 142                 trigger_bindat="$trigger_bindat$(printf '\\%o\\%o' $mask $val1)"
 143                 [ $val1 -ne $val2 ] && trigger_bindat="$trigger_bindat$(printf '\\%o\\%o' $mask $val2)"
 144         done
 145         IFS="$oldifs"
 146 }
 147
 148 do_capture()
 149 {
 150         taskset "$1" echo 1 > "$lasysfsdir"/capture || fail "Capture error! Check kernel log"
 151
 152         srtmp=$(mktemp -d)
 153         echo 1 > "$srtmp"/version
 154         cp "$lasysfsdir"/sample_data "$srtmp"/logic-1-1
 155         cat > "$srtmp"/metadata << EOF
 156 [global]
 157 sigrok version=0.2.0
 158
 159 [device 1]
 160 capturefile=logic-1
 161 total probes=$(wc -l < "$lasysfsdir"/meta_data)
 162 samplerate=${samplefreq}Hz
 163 unitsize=1
 164 EOF
 165         cat "$lasysfsdir"/meta_data >> "$srtmp"/metadata
 166
 167         zipname="$outputdir/${lasysfsdir##*/}-$(date +%s).sr"
 168         zip -jq "$zipname" "$srtmp"/*
 169         rm -rf "$srtmp"
 170         delay_ack=$(cat "$lasysfsdir"/delay_ns_acquisition)
 171         [ "$delay_ack" -eq 0 ] && delay_ack=1
 172         echo "Logic analyzer done. Saved '$zipname'"
 173         echo "Max sample frequency this time: $((1000000000 / delay_ack))Hz."
 174 }
 175
 176 rep=$(getopt -a -l cpu:,duration-us:,help,instance:,list-instances,kernel-debug-dir:,num_samples:,output-dir:,sample_freq:,trigger: -o c:d:hi:k:ln:o:s:t: -- "$@") || exit 1
 177 eval set -- "$rep"
 178 while true; do
 179         case "$1" in
 180         -c|--cpu) initcpu="$2"; shift;;
 181         -d|--duration-us) parse_si $2; duration=$si_val; shift;;
 182         -h|--help) print_help; exit 0;;
 183         -i|--instance) lainstance="$2"; shift;;
 184         -k|--kernel-debug-dir) debugdir="$2"; shift;;
 185         -l|--list-instances) listinstances=1;;
 186         -n|--num_samples) parse_si $2; numsamples=$si_val; shift;;
 187         -o|--output-dir) outputdir="$2"; shift;;
 188         -s|--sample_freq) parse_si $2; samplefreq=$si_val; shift;;
 189         -t|--trigger) triggerdat="$2"; shift;;
 190         --) break;;
 191         *) fail "error parsing command line: $*";;
 192         esac
 193         shift
 194 done
 195
 196 for f in $neededcmds; do
 197         command -v "$f" >/dev/null || fail "Command '$f' not found"
 198 done
 199
 200 # print cpuset mountpoint if any, errorcode > 0 if noprefix option was found
 201 cpusetdir=$(awk '$3 == "cgroup" && $4 ~ /cpuset/ { print $2; exit (match($4, /noprefix/) > 0) }' /proc/self/mounts) || cpusetprefix=''
 202 if [ -z "$cpusetdir" ]; then
 203         cpusetdir="$cpusetdefaultdir"
 204         [ -d $cpusetdir ] || mkdir $cpusetdir
 205         mount -t cgroup -o cpuset none $cpusetdir || fail "Couldn't mount cpusets. Not in kernel or already in use?"
 206 fi
 207
 208 lacpusetdir="$cpusetdir/$ladirname"
 209 lacpusetfile="$lacpusetdir/$cpusetprefix"
 210 sysfsdir="$debugdir/$ladirname"
 211
 212 [ "$samplefreq" -ne 0 ] || fail "Invalid sample frequency"
 213
 214 [ -d "$sysfsdir" ] || fail "Could not find logic analyzer root dir '$sysfsdir'. Module loaded?"
 215 [ -x "$sysfsdir" ] || fail "Could not access logic analyzer root dir '$sysfsdir'. Need root?"
 216
 217 [ $listinstances -gt 0 ] && find "$sysfsdir" -mindepth 1 -type d | sed 's|.*/||' && exit 0
 218
 219 if [ -n "$lainstance" ]; then
 220         lasysfsdir="$sysfsdir/$lainstance"
 221 else
 222         lasysfsdir=$(find "$sysfsdir" -mindepth 1 -type d -print -quit)
 223 fi
 224 [ -d "$lasysfsdir" ] || fail "Logic analyzer directory '$lasysfsdir' not found!"
 225 [ -d "$outputdir" ] || fail "Output directory '$outputdir' not found!"
 226
 227 [ -n "$initcpu" ] && init_cpu "$initcpu"
 228 [ -d "$lacpusetdir" ] || { echo "Auto-Isolating CPU1"; init_cpu 1; }
 229
 230 ndelay=$((1000000000 / samplefreq))
 231 echo "$ndelay" > "$lasysfsdir"/delay_ns
 232
 233 [ -n "$duration" ] && numsamples=$((samplefreq * duration / 1000000))
 234 echo $numsamples > "$lasysfsdir"/buf_size
 235
 236 if [ -n "$triggerdat" ]; then
 237         parse_triggerdat "$triggerdat"
 238         printf "$trigger_bindat" > "$lasysfsdir"/trigger 2>/dev/null || fail "Trigger data '$triggerdat' rejected"
 239 fi
 240
 241 workcpu=$(cat "${lacpusetfile}effective_cpus")
 242 [ -n "$workcpu" ] || fail "No isolated CPU found"
 243 cpumask=$(printf '%x' $((1 << workcpu)))
 244 instance=${lasysfsdir##*/}
 245 echo "Setting up '$instance': $numsamples samples at ${samplefreq}Hz with ${triggerdat:-no} trigger using CPU$workcpu"
 246 do_capture "$cpumask" &