defaults: Improve reliability of bluetooth-brcmfmac against system suspend

hciattach isn't aware that the card gets reset at system suspend, requiring
full reinitialization, so it needs to be restarted. Unfortunately,
I haven't found a way to describe such relation using systemd unit
relations alone that wouldn't break things, so a system-sleep hook
is added to stop the service before going into suspend.

The service itself is also tweaked to better handle errors and to make
it restartable (previously it would require the card to be reset before
hciattach could work again).

Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>

debian/librem5-base-defaults.bluetooth-brcmfmac.service

@@ -3,10 +3,12 @@ Description=Bluetooth attachment for brcmfmac driver
 After=sys-bus-sdio-drivers-brcmfmac-mmc1:0001:1.device
 BindsTo=sys-bus-sdio-drivers-brcmfmac-mmc1:0001:1.device
 ConditionPathExists=/etc/firmware/brcm/BCM4362A2.hcd
+StopWhenUnneeded=true
 
 [Install]
-WantedBy=sys-bus-sdio-drivers-brcmfmac-mmc1:0001:1.device
+RequiredBy=sys-bus-sdio-drivers-brcmfmac-mmc1:0001:1.device
 
 [Service]
 Type=forking
-ExecStart=/usr/bin/hciattach -s 115200 /dev/ttymxc3 bcm43xx 1500000
+ExecStart=sh -c '/usr/bin/hciattach -s 115200 /dev/ttymxc3 bcm43xx 1500000 || /usr/bin/hciattach -s 1500000 /dev/ttymxc3 bcm43xx 1500000'
+Restart=on-abort

debian/librem5-base-defaults.install

@@ -56,6 +56,9 @@ default/systemd/systemd-localed.service.d/*	lib/systemd/system/systemd-localed.s
 # enable zram
 default/systemd/zram-generator.conf.d/*	lib/systemd/zram-generator.conf.d/
 
+# suspend hooks
+default/systemd/system-sleep/*		lib/systemd/system-sleep/
+
 # initramfs modules
 default/initramfs-tools/modules.d/*	usr/share/initramfs-tools/modules.d/
 

default/systemd/system-sleep/bluetooth-brcmfmac

+#!/bin/sh
+# Stop hciattach before system suspend to not interfere with
+# freshly reset card after resume.
+#
+# No need to start it back here as it gets restarted automatically
+# because of RequiredBy relation in its systemd unit.
+case "${1}/${2}" in
+        hibernate|suspend|pre*)
+                systemctl stop bluetooth-brcmfmac.service
+                ;;
+esac