USB Serial: Add fallback rule and script

This rule makes it easier to use CCD devices when the raiden module
can't be installed for some reason.  The rule informs the usbserial
module that it should handle anything that looks like a simple serial
port for any CCD compatible USB devices.

The install script now detects failure when building and installing
the raiden module and offers the --fallback option in that case.

Signed-off-by: Anton Staaf <robotboy@chromium.org>

BRANCH=None
BUG=None
TEST=make buildall -j

Change-Id: I617bbdfb4c5cb9e9803f4088c651f84e3f72bd28
Reviewed-on: https://chromium-review.googlesource.com/351873
Commit-Ready: Anton Staaf <robotboy@chromium.org>
Tested-by: Anton Staaf <robotboy@chromium.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

3 files changed, 114 insertions, 7 deletions

diff --git a/extra/usb_serial/51-google-serial-fallback.rules b/extra/usb_serial/51-google-serial-fallback.rules
new file mode 100644
index 0000000000..5f43e58e30
--- /dev/null
+++ b/extra/usb_serial/51-google-serial-fallback.rules
@@ -0,0 +1,6 @@
+#
+# Add USB VID/PID for usb-serial compatible CCD devices.  This is a fallback
+# rule that can be used if the raiden module can't be built, or used for some
+# reason.
+#
+SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ATTR{idVendor}=="18d1", ENV{ID_USB_INTERFACES}=="*:ff5001:*", RUN+="add_usb_serial_id $attr{idVendor} $attr{idProduct}"
diff --git a/extra/usb_serial/add_usb_serial_id b/extra/usb_serial/add_usb_serial_id
new file mode 100755
index 0000000000..ef8336afdc
--- /dev/null
+++ b/extra/usb_serial/add_usb_serial_id
@@ -0,0 +1,32 @@
+#!/bin/sh -e
+#
+# Copyright 2016 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+#
+# Add a USB VID:PID device ID to the usbserial list of handled devices
+
+if [ $# -ne 2 ]; then
+    echo ""
+    echo "Usage: $0 <VID> <PID>"
+    echo ""
+    echo "Add a USB VID:PID device identification pair to the list of devices"
+    echo "that usbserial will recognize.  This script ensures that a device is"
+    echo "not added more than once."
+    echo ""
+    exit 1
+fi
+
+#
+# Firts ensure that the usbserial module is loaded.  This is required as there
+# may be no other USB serial adaptor connected yet.
+#
+modprobe usbserial
+
+device_id="$1 $2"
+file="/sys/bus/usb-serial/drivers/generic/new_id"
+
+#
+# Only add the device ID pair if it isn't already in the ID list.
+#
+grep -q "$device_id" $file || echo $device_id > $file
diff --git a/extra/usb_serial/install b/extra/usb_serial/install
index f802f10af4..eba1d2ac83 100755
--- a/extra/usb_serial/install
+++ b/extra/usb_serial/install
@@ -1,19 +1,88 @@
-#!/bin/sh
+#!/bin/sh -e
+#
+# Copyright 2016 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+#
+# Build and install raiden module and udev rules
 
-set -e
+bold=$(tput bold)
+normal=$(tput sgr0)
 
-make modules
+error() {
+    echo "${bold}Install failed${normal}"
+}
 
-# Install the new module and update dependency and alias information
-sudo make modules_install
-sudo depmod -a
+trap "error $LINENO" ERR
 
+fallback=false
+
+if [ "$1" = "--fallback" ]; then
+    fallback=true
+    shift
+fi
+
+if [ $# -ne 0 ]; then
+    echo ""
+    echo "Usage: ${bold}$0${normal} [--fallback]"
+    echo ""
+    echo "Install Raiden kernel module and udev rules for working with Case"
+    echo "Closed Debug enabled devices."
+    echo ""
+    echo "${bold}--fallback${normal}"
+    echo "    Install udev rules to use usbserial directly without installing"
+    echo "    the raiden module.  This can be used when the raiden module fails"
+    echo "    to build, or can not be used for other reasons."
+    echo ""
+    echo "    The fallback solution will generate extra /dev/ttyUSB? entries"
+    echo "    for the SPI and possibly other CCD bridges.  These should be"
+    echo "    ignored by you.  Flashrom is smart enough to detach the kernel"
+    echo "    driver from the SPI bridge, so they will not interfere with"
+    echo "    flashing new firmware images over CCD."
+    echo ""
+    exit 1
+fi
+
+if [ "$fallback" = "false" ]; then
+    #
+    # The normal path builds and installs the raiden module
+    #
+    {
+	#
+	# Don't build the module as root so it's easier to clean up after
+	#
+	make modules &&
+
+	#
+	# Install the new module and update dependency and alias information
+	#
+	sudo make modules_install &&
+	sudo depmod -a
+    } || {
+	echo $bold
+	echo "Building and/or installing the raiden module failed, you may"
+	echo "want to use the --fallback option."
+	echo $normal
+	exit 1;
+    }
+else
+    #
+    # The fallback path installs the fallback udev rule and its helper script.
+    #
+    sudo install -m644 51-google-serial-fallback.rules /etc/udev/rules.d
+    sudo install add_usb_serial_id /lib/udev
+fi
+
+#
 # Install the udev rule for creating /dev/google symlinks.
-sudo cp 51-google-serial.rules /etc/udev/rules.d
+#
+sudo install -m644  51-google-serial.rules /etc/udev/rules.d
 
+#
 # Trigger udev to create the symlinks for any attached devices that have the
 # Google Vendor ID.  Limiting triggering like this prevents unwanted resetting
 # of some device state, even with the change action specified.
+#
 for syspath in $(dirname $(grep -rxl --include=idVendor 18d1 /sys/devices)); do
     sudo udevadm trigger --action=change --parent-match=${syspath}
 done