Add ARM System Profiler example usage script

The ARM System Profiler driver exposes System Profiler registers via.
debugfs files. The user space can program and later capture metrics from
System Profiler by accessing these files.

This script stands as an example for the System Profiler's usage.

diff --git a/scripts/arm-system-profiler-example.sh b/scripts/arm-system-profiler-example.sh
new file mode 100644 (file)
index 0000000..8c972f6
--- /dev/null
+++ b/scripts/arm-system-profiler-example.sh
@@ -0,0 +1,171 @@
+#!/bin/bash
+#
+# ARM System Profiler usage example
+#
+# Copyright (C) 2014 ARM Limited
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+#
+# This program is distributed "as is" WITHOUT ANY WARRANTY of any
+# kind, whether express or implied; without even the implied warranty
+# of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+#
+# This script demonstrates the usage of ARM System Profiler platform to capture
+# and extract various performance-related events from the System Profiler
+# hardware.
+#
+# The ARM System Profiler driver exposes System Profiler registers as debugfs
+# files through which user space can access them. The user programs necessary
+# filters, and configure counters, and later triggers capture event.  Upon a
+# capture event, System Profiler exposes the collected metrics though its shadow
+# registers
+#
+# This script collects some unfiltered events from AXI bus monitors connected to
+# A57 and A53 clusters, and operates the Profiler in software stream mode. This
+# however is only a example and doesn't of capabilities of System Profiler. For
+# more information, see ARM DDI0520 System Profiler Technical Reference Manual
+#
+# ARM System Profiler driver is located at drivers/bus/arm-system-profiler.c
+#
+
+# System Profiler root under debugfs
+sp_root="/sys/kernel/debug/arm-system-profiler"
+
+# The command to execute, after which we capture metrics. The command itself has
+# no significance, except that it exercises a decent number of data transactions
+# through the system
+command="tar cz /usr/bin 2>/dev/null | md5sum &>/dev/null"
+
+# Check if debugfs is mounted
+if [ ! -d "/sys/kernel/debug" ]; then
+       echo "Debugfs not mounted"
+       exit 1
+fi
+
+# Check if System Profiler driver is enabled
+if [ ! -d "$sp_root" ]; then
+       echo "Unable to locate System Profiler root dir '$sp_root'"
+       echo "Is ARM System Profiler driver enabled?"
+       exit 1
+fi
+
+# Obtain System Profiler device root. We pick the first device listed.
+pushd "$sp_root" &>/dev/null
+if [ -z "$sp_device" ]; then
+       sp_device="$(find -maxdepth 1 -type d | sed -n '2{s/^\.\///;p;q}')"
+       if [ -z "$sp_device" ]; then
+               echo "No System Profiler instance found under '$sp_root'"
+               exit 1
+       fi
+elif [ ! -d "$sp_device" ]; then
+       echo "No System Profiler instance '$sp_device' found under '$sp_root'"
+       exit 1
+fi
+popd &>/dev/null
+
+# System Profiler directory
+system_profiler="$sp_root/$sp_device"
+
+# Verify the monitors what we need have been implemented
+im="$(cat "$system_profiler/MTR_IM")"
+for p in 0 1; do
+       let "imp = im & (1 << $p)"
+       if [ "$imp" == 0 ]; then
+               echo "$sp_device: Monitor $p not implemented"
+               exit 1
+       fi
+
+       if [ ! -d "$system_profiler/port$p" ]; then
+               echo "$sp_device: No port $p"
+               exit 1
+       fi
+done
+
+#
+# Now programm actual registers
+#
+function regw() {
+       [ "$debug" ] && printf " write %-20s <- %s\n" $1 $2
+       echo "$2" > "$1"
+}
+
+cd "$system_profiler"
+
+# Disable System Profiler
+regw CTRL 0x0
+
+# Configure in software stream mode
+regw CFG 0x0
+
+# Enable Monitors 0 and 1
+regw MTR_EN 0x3
+
+# Disable interrupts
+regw INT_EN 0x0
+
+# Program both AXI monitors to accumulation mode
+regw port0/ABM_MODE 0x0
+regw port1/ABM_MODE 0x0
+
+# Disable all filters
+regw port0/FLTEN 0x0
+regw port1/FLTEN 0x0
+
+# Since we aren't using any filters, configure counters to count unfiltered
+# transactions
+c_cfg=(0 1 2 3)
+for p in 0 1; do
+       for c in 1 2 3 4; do
+               for rw in R W; do
+                       regw "port$p/C${rw}${c}SEL" "${c_cfg[$c - 1]}"
+               done
+       done
+done
+
+# Enable System Profiler
+regw CTRL 0x5
+
+# Run 6 different instances of our command which hopefully will spawn on all
+# different cores, and wait for them finish
+echo "Spawning commands:"
+for i in {1..6}; do
+       eval "{ $command; } &"
+       echo "  command: [$!] $command"
+done
+
+echo "Waiting for commands to finish..."
+wait
+
+# Commands have finished running. Generate a capture event so that the metrics
+# will be transferred to shadow registers
+regw CTRL 0x2
+
+# Wait until System Profiler has finished capturing from all its monitors. This
+# will be reflected in SP_STATUS.CAP_ACK
+while :; do
+       ack=$(cat SP_STATUS)
+       let "ack &= 1"
+       [ "$ack" == 1 ] && break
+done
+
+# Now that System Profiler has captured the metrics, all data must be available
+# in the shadow registers to collect. Print it out
+echo
+echo "Shadow registers post capture:"
+for p in 0 1; do
+       echo "  Port $p:"
+       for i in {0..11}; do
+               printf "    %-4s: %s\n" "SR$i" "$(cat port$p/SR$i)"
+       done
+       echo
+done
+
+# Disable System Profiler (flip bit 0)
+regw CTRL 0x4
+
+exit 0
+