utils: introduce find_usbdebug.sh to help find USB debug ports

Carl-Daniel made this script a long time ago but it never was picked up
in the tree. Now that USB debugging is way more common it makes
sense to include it.

I have made a number of changes to the original version:
* -h help text
* check for running as root
* enhanced readability (test -> if)
* new execution flow and refined output that better shows the device(s)
  attached to the debug port(s)
* handling of Intel rate-matching hubs
* hiding of (bogus) error messages from lspci and lsusb

Signed-off-by: Stefan Tauner <stefan.tauner@gmx.at>
Change-Id: Iadf775e990f5c5f91a28d57e3331d1f59acee305
Reviewed-on: https://review.coreboot.org/c/9305
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

3 files changed, 171 insertions, 0 deletions

diff --git a/util/README.md b/util/README.md
index bd1398bafb..470013ed25 100644
--- a/util/README.md
+++ b/util/README.md
@@ -38,6 +38,7 @@ _coreboot.org-status_ and _docs.coreboot.org_
 Controller (EC). `C`
 * __exynos__ - Computes and fills Exynos ROM checksum (for BL1 or BL2).
 `Python2`
+* __find_usbdebug__ - Help find USB debug ports
 * __futility__ - Firmware utility for signing ChromeOS images `Make`
 * __fuzz-tests__ - Create test cases that crash the jpeg code. `C`
 * __genbuild_h__ - Generate build system definitions `Shell`
diff --git a/util/find_usbdebug/description.md b/util/find_usbdebug/description.md
new file mode 100644
index 0000000000..1497603314
--- /dev/null
+++ b/util/find_usbdebug/description.md
@@ -0,0 +1 @@
+Help find USB debug ports
diff --git a/util/find_usbdebug/find_usbdebug.sh b/util/find_usbdebug/find_usbdebug.sh
new file mode 100755
index 0000000000..c7b2e7e8da
--- /dev/null
+++ b/util/find_usbdebug/find_usbdebug.sh
@@ -0,0 +1,169 @@
+#!/bin/bash
+
+# Copyright 2008 Carl-Daniel Hailfinger
+# Copyright 2015 Stefan Tauner
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+LANG=C
+# Some tools emit errors that don't matter (bugs in lspci/PCI firmware and lsusb).
+# To shown them anyway (e.g. for debugging) comment next line.
+exec 2>/dev/null
+
+if [ "$1" = "-h" ]; then
+	printf "Usage: $0 [-h | path to dmesg log]
+
+This script tries to find USB ports compatible with USB2/EHCI debug devices and
+helps you to find their physical locations. To that end, attach at least one
+uniquely identifiable device to a USB port and run this script. The device needs
+to be visible in the output of \"lsusb -t\" (debug devices are often *not*!).
+
+After determining compatibility of the USB controllers the script will print the
+devices attached to the debug port as shown by lsusb. If nothing shows up simply
+switch ports and repeat the process.
+
+Note: usually only one port is supported for debugging.\n"
+	exit 0
+fi
+uid=`id -u`
+if [ "$uid" -ne 0 ]; then
+	echo "Must be run as root. Exiting."
+	exit 1
+fi
+dmesgfile=$1
+
+find_devs_in_tree () {
+	bus=$1
+	port=$2
+	busstr=`printf "Bus %02d" "$bus"`
+	portstr="Port $port"
+
+	hubs_to_ignore="8087:0020 8087:0024"
+	reqlvl=1
+
+	found=
+	# Iterate over the output of lsusb -t because it contains the physical port numbers
+	while IFS='' read -r line; do
+		# We need to keep track of the current bus "branch"
+		# Look out for lines starting with /: (that indicate a bus)
+		if [ "${line#*/:}" != "$line" ]; then
+			if [ "${line#*$busstr}" != "$line" ]; then
+				cur_bus=$busstr
+			else
+				cur_bus=
+			fi
+			continue
+		fi
+
+		# Skip all lines not belonging to the wanted bus number
+		if [ "$cur_bus" != "$busstr" ]; then
+			continue
+		fi
+
+		# Calculate current USB tier/level
+		spaces="${line%%[!' ']*}"
+		curlvl=$((${#spaces} / 4))
+		if [ $curlvl -ne $reqlvl ]; then
+			continue
+		fi
+
+		# Fetch USB IDs of the current device
+		dev=`echo ${line#*Dev } | cut -d ',' -f 1`
+		lsusbline=`lsusb -s "$bus":"$dev"`
+		if [[ ! "$lsusbline" =~ .*([[:xdigit:]]{4}:[[:xdigit:]]{4}) ]]; then
+			printf "Unexpected output from \"%s\": \"%s\"\n" "lsusb -s $bus:$dev" "$usbline"
+			exit 1
+		fi
+		ids=${BASH_REMATCH[1]}
+
+		# Skip over rate matching hubs
+		if [[ "$hubs_to_ignore" == *"$ids"* ]]; then
+			((reqlvl += 1))
+			continue
+		fi
+
+		# Check for matching physical USB port
+		if [ "${line#*$portstr}" != "$line" ]; then
+			echo "$lsusbline"
+			return
+		fi
+	done<< EOF
+$(lsusb -t)
+EOF
+	if [ -z "$found" ]; then
+		echo "none"
+	fi
+}
+
+debug_lspci_devs=`lspci -nvvD |
+	grep -i "^[0-9a-f]\|debug port" |
+	grep -iB1 --no-group-separator "debug port" |
+	grep -vi "debug port" |
+	cut -f 1 -d" " |
+	sort |
+	xargs echo`
+
+if [ -z "$debug_lspci_devs" ]; then
+	printf "No USB controller with debug capability found by lspci.\n
+Possible reasons: lspci too old, USB controller does not support a debug device, ... Exiting.\n"
+	exit 1
+fi
+printf "The following PCI devices support a USB debug port (says lspci): $debug_lspci_devs\n"
+
+debug_dmesg_devs_with_port=`( test -z "$dmesgfile" &&
+	dmesg ||
+	cat "$dmesgfile") |
+	grep -i "ehci.*debug port" |
+	sed "s/.* \([0-9a-f]*:*[0-9a-f]\{2\}:[0-9a-f]\{2\}\.[0-9a-f]\).*ebug port /\1 /" |
+	sort`
+
+debug_dmesg_devs=`echo "$debug_dmesg_devs_with_port" |
+	cut -f 1 -d" " |
+	xargs echo`
+
+if [ -z "$debug_dmesg_devs" ]; then
+	printf "dmesg does not show any supported ports.\n
+Possible reasons: dmesg scrolled off, kernel too old, USB controller does not support a debug device, ... Exiting.\n
+Note: You can specify a file containing kernel messages as an argument to this program (e.g. /var/log/dmesg)."
+	exit 1
+fi
+
+if [ "$debug_lspci_devs" != "$debug_dmesg_devs" ]; then
+	echo "lspci and the kernel do not agree on USB debug device support. Exiting."
+	exit 1
+fi
+
+printf "and the kernel agrees, good.\n\n"
+
+while true; do
+	for dev in $debug_dmesg_devs; do
+		bus=`lsusb -v |
+			grep "^Bus\|iSerial.*" |
+			grep -B1 --no-group-separator "iSerial.*$dev" |
+			grep "^Bus" |
+			sed "s/Bus *0*\([0-9a-f]*\).*/\1/"`
+		port=`echo "$debug_dmesg_devs_with_port" |
+			grep "^$dev" |
+			cut -f 2 -d" "`
+
+		echo "Device(s) currently connected to the debug-capable port $port on PCI device $dev, USB bus $bus:"
+
+		find_devs_in_tree "$bus" "$port"
+		echo
+	done
+
+	echo "Enter 'q' to abort or anything else to repeat"
+	read -r r
+	if [ $? -ne 0 -o "$r" = "q" ]; then
+		break;
+	fi
+done
+
+exit 0