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" "$p" || continue
114 done 2>/dev/null >/dev/null
115
116 # Big hammer! Working with 'rcu_momentary_dyntick_idle()' for a more fine-grained solution
117 # still printed warnings. Same for re-enabling the stall detector after sampling.
118 echo 1 > /sys/module/rcupdate/parameters/rcu_cpu_stall_suppress
119
120 cpufreqgov="/sys/devices/system/cpu/cpu$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" &
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