tests: Bluetooth: add minimal coverage for BT_RECV_WORKQ_SYS

Run the l2cap stress test so we have some minimal runtime coverage of that
config.

Signed-off-by: Jonathan Rico <jonathan.rico@nordicsemi.no>

tests/bsim/bluetooth/host/l2cap/compile.sh

@@ -22,6 +22,7 @@ source ${ZEPHYR_BASE}/tests/bsim/compile.source
 app=tests/bsim/bluetooth/host/l2cap/general compile
 app=tests/bsim/bluetooth/host/l2cap/userdata compile
 app=tests/bsim/bluetooth/host/l2cap/stress compile
+app=tests/bsim/bluetooth/host/l2cap/stress conf_file=prj_syswq.conf compile
 app=tests/bsim/bluetooth/host/l2cap/split/dut compile
 app=tests/bsim/bluetooth/host/l2cap/split/tester compile
 app=tests/bsim/bluetooth/host/l2cap/credits compile

tests/bsim/bluetooth/host/l2cap/stress/prj_syswq.conf

@@ -0,0 +1,57 @@
+CONFIG_BT=y
+CONFIG_BT_CENTRAL=y
+CONFIG_BT_PERIPHERAL=y
+CONFIG_BT_DEVICE_NAME="L2CAP stress test"
+
+CONFIG_BT_EATT=n
+CONFIG_BT_L2CAP_ECRED=n
+
+CONFIG_BT_SMP=y # Next config depends on it
+CONFIG_BT_L2CAP_DYNAMIC_CHANNEL=y
+
+# Disable auto-initiated procedures so they don't
+# mess with the test's execution.
+CONFIG_BT_AUTO_PHY_UPDATE=n
+CONFIG_BT_AUTO_DATA_LEN_UPDATE=n
+CONFIG_BT_GAP_AUTO_UPDATE_CONN_PARAMS=n
+
+# L2CAP MPS
+# 23+27+27=77 makes exactly three full packets
+CONFIG_BT_L2CAP_TX_MTU=77
+
+# Use this to send L2CAP PDUs without any fragmentation.
+# In this particular case, we prefer fragmenting to test that code path.
+# CONFIG_BT_BUF_ACL_TX_SIZE=81
+
+# L2CAP PDUs will be fragmented in 3 ACL packets.
+CONFIG_BT_BUF_ACL_TX_SIZE=27
+
+CONFIG_BT_BUF_ACL_TX_COUNT=4
+
+# The minimum value for this is
+# L2AP MPS + L2CAP header (4)
+CONFIG_BT_BUF_ACL_RX_SIZE=81
+
+# Governs BT_CONN_TX_MAX, and so must be >= than the max number of
+# peers, since we attempt to send one SDU per peer. The test execution
+# is a bit slowed down by having this at the very minimum, but we want
+# to keep it that way as to stress the stack as much as possible.
+CONFIG_BT_L2CAP_TX_BUF_COUNT=6
+
+CONFIG_BT_CTLR_DATA_LENGTH_MAX=27
+CONFIG_BT_CTLR_RX_BUFFERS=10
+
+CONFIG_BT_MAX_CONN=10
+
+CONFIG_LOG=y
+CONFIG_ASSERT=y
+CONFIG_NET_BUF_POOL_USAGE=y
+
+CONFIG_BT_L2CAP_LOG_LEVEL_DBG=y
+# CONFIG_BT_CONN_LOG_LEVEL_DBG=y
+CONFIG_LOG_THREAD_ID_PREFIX=y
+CONFIG_THREAD_NAME=y
+
+CONFIG_ARCH_POSIX_TRAP_ON_FATAL=y
+
+CONFIG_BT_RECV_WORKQ_SYS=y

tests/bsim/bluetooth/host/l2cap/stress/tests_scripts/l2cap_syswq.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+# Copyright (c) 2022 Nordic Semiconductor
+# SPDX-License-Identifier: Apache-2.0
+
+source ${ZEPHYR_BASE}/tests/bsim/sh_common.source
+
+# EATT test
+simulation_id="l2cap_stress_syswq"
+verbosity_level=2
+EXECUTE_TIMEOUT=120
+
+cd ${BSIM_OUT_PATH}/bin
+
+bsim_exe=./bs_${BOARD}_tests_bsim_bluetooth_host_l2cap_stress_prj_syswq_conf
+
+Execute "${bsim_exe}" -v=${verbosity_level} -s=${simulation_id} -d=0 -testid=central -rs=43
+
+Execute "${bsim_exe}" -v=${verbosity_level} -s=${simulation_id} -d=1 -testid=peripheral -rs=42
+Execute "${bsim_exe}" -v=${verbosity_level} -s=${simulation_id} -d=2 -testid=peripheral -rs=10
+Execute "${bsim_exe}" -v=${verbosity_level} -s=${simulation_id} -d=3 -testid=peripheral -rs=23
+Execute "${bsim_exe}" -v=${verbosity_level} -s=${simulation_id} -d=4 -testid=peripheral -rs=7884
+Execute "${bsim_exe}" -v=${verbosity_level} -s=${simulation_id} -d=5 -testid=peripheral -rs=230
+Execute "${bsim_exe}" -v=${verbosity_level} -s=${simulation_id} -d=6 -testid=peripheral -rs=9
+
+Execute ./bs_2G4_phy_v1 -v=${verbosity_level} -s=${simulation_id} -D=7 -sim_length=400e6 $@
+
+wait_for_background_jobs