selftests/powerpc: Hoist helper code out of eeh-basic

Hoist some of the useful test environment checking and prep code into
eeh-functions.sh so they can be reused in other tests.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201103044503.917128-1-oohall@gmail.com

tools/testing/selftests/powerpc/eeh/eeh-basic.sh

 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0-only
 
-KSELFTESTS_SKIP=4
-
 . ./eeh-functions.sh
 
-if ! eeh_supported ; then
-	echo "EEH not supported on this system, skipping"
-	exit $KSELFTESTS_SKIP;
-fi
-
-if [ ! -e "/sys/kernel/debug/powerpc/eeh_dev_check" ] && \
-   [ ! -e "/sys/kernel/debug/powerpc/eeh_dev_break" ] ; then
-	echo "debugfs EEH testing files are missing. Is debugfs mounted?"
-	exit $KSELFTESTS_SKIP;
-fi
+eeh_test_prep # NB: may exit
 
 pre_lspci=`mktemp`
 lspci > $pre_lspci
 
-# Bump the max freeze count to something absurd so we don't
-# trip over it while breaking things.
-echo 5000 > /sys/kernel/debug/powerpc/eeh_max_freezes
-
 # record the devices that we break in here. Assuming everything
 # goes to plan we should get them back once the recover process
 # is finished.
@@ -30,34 +15,16 @@ devices=""
 
 # Build up a list of candidate devices.
 for dev in `ls -1 /sys/bus/pci/devices/ | grep '\.0$'` ; do
-	# skip bridges since we can't recover them (yet...)
-	if [ -e "/sys/bus/pci/devices/$dev/pci_bus" ] ; then
-		echo "$dev, Skipped: bridge"
+	if ! eeh_can_break $dev ; then
 		continue;
 	fi
 
-	# Skip VFs for now since we don't have a reliable way
-	# to break them.
+	# Skip VFs for now since we don't have a reliable way to break them.
 	if [ -e "/sys/bus/pci/devices/$dev/physfn" ] ; then
 		echo "$dev, Skipped: virtfn"
 		continue;
 	fi
 
-	if [ "ahci" = "$(basename $(realpath /sys/bus/pci/devices/$dev/driver))" ] ; then
-		echo "$dev, Skipped: ahci doesn't support recovery"
-		continue
-	fi
-
-	# Don't inject errosr into an already-frozen PE. This happens with
-	# PEs that contain multiple PCI devices (e.g. multi-function cards)
-	# and injecting new errors during the recovery process will probably
-	# result in the recovery failing and the device being marked as
-	# failed.
-	if ! pe_ok $dev ; then
-		echo "$dev, Skipped: Bad initial PE state"
-		continue;
-	fi
-
 	echo "$dev, Added"
 
 	# Add to this list of device to check

tools/testing/selftests/powerpc/eeh/eeh-functions.sh

 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0-only
 
+export KSELFTESTS_SKIP=4
+
 pe_ok() {
 	local dev="$1"
 	local path="/sys/bus/pci/devices/$dev/eeh_pe_state"
@@ -39,6 +41,52 @@ eeh_supported() {
 	grep -q 'EEH Subsystem is enabled' /proc/powerpc/eeh
 }
 
+eeh_test_prep() {
+	if ! eeh_supported ; then
+		echo "EEH not supported on this system, skipping"
+		exit $KSELFTESTS_SKIP;
+	fi
+
+	if [ ! -e "/sys/kernel/debug/powerpc/eeh_dev_check" ] && \
+	   [ ! -e "/sys/kernel/debug/powerpc/eeh_dev_break" ] ; then
+		echo "debugfs EEH testing files are missing. Is debugfs mounted?"
+		exit $KSELFTESTS_SKIP;
+	fi
+
+	# Bump the max freeze count to something absurd so we don't
+	# trip over it while breaking things.
+	echo 5000 > /sys/kernel/debug/powerpc/eeh_max_freezes
+}
+
+eeh_can_break() {
+	# skip bridges since we can't recover them (yet...)
+	if [ -e "/sys/bus/pci/devices/$dev/pci_bus" ] ; then
+		echo "$dev, Skipped: bridge"
+		return 1;
+	fi
+
+	# The ahci driver doesn't support error recovery. If the ahci device
+	# happens to be hosting the root filesystem, and then we go and break
+	# it the system will generally go down. We should probably fix that
+	# at some point
+	if [ "ahci" = "$(basename $(realpath /sys/bus/pci/devices/$dev/driver))" ] ; then
+		echo "$dev, Skipped: ahci doesn't support recovery"
+		return 1;
+	fi
+
+	# Don't inject errosr into an already-frozen PE. This happens with
+	# PEs that contain multiple PCI devices (e.g. multi-function cards)
+	# and injecting new errors during the recovery process will probably
+	# result in the recovery failing and the device being marked as
+	# failed.
+	if ! pe_ok $dev ; then
+		echo "$dev, Skipped: Bad initial PE state"
+		return 1;
+	fi
+
+	return 0
+}
+
 eeh_one_dev() {
 	local dev="$1"