Simone
3cd1d6e0a6
The driver reached the PCU function's config space by walking the ACPI MCFG
table and mapping the ECAM page itself. That is one leaf driver deciding
config-space policy, and no other driver in mainline does it, so it was the
single most likely reason for a NAK.
Move that decision where it belongs: the upstream series is now two patches,
a PCI/x86 accessor that forces the memory-mapped path with the core's
locking, and this driver on top of it. Reviewers on each side now get
something they can act on, and get_maintainer.pl selects the PCI and x86
people by itself.
Correctness work in the same pass:
- the completion bits are latched, so a command the engine never accepted
was indistinguishable from a completed one and returned the previous
transaction's data as valid. Require a positive sign that the engine
acted on the command;
- compare the command registers after every transfer against what the
driver left in them and fail with -EAGAIN on a mismatch. The original
iMC driver had this check and it is what makes an unarbitrated system
detectable instead of silently wrong;
- use the i2c core's suspended-adapter mechanism rather than a private
flag and -EHOSTDOWN;
- use devm_mutex_init(), drop the unnecessary pci_enable_device(), and
return -ENODEV rather than -EPERM from the default-off gate, which was
printing a driver-core error on every boot;
- mask GO when restoring a saved command word.
Stop attributing the dropped CF8/CFC write to System Management Mode. The
only evidence was a boot log line naming the access method, which says
nothing about who filters the write. tools/probe-cf8-write.sh is there to
settle it with an MSR_SMI_COUNT measurement.
Add Documentation/i2c/busses/i2c-imc-skylake.rst, which every other PC SMBus
driver has and which was explicitly asked for on the 2020 iMC thread, the
tools/ scripts for the hardware measurements the submission still owes, and
compat/pci-mmcfg-compat.h so the driver still builds out-of-tree against a
kernel without the new accessor while the source stays byte-identical to the
submitted patch.
253 lines
6.3 KiB
Bash
Executable File
253 lines
6.3 KiB
Bash
Executable File
#!/usr/bin/env bash
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# Read-only smoke test for i2c-imc-skylake.
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set -euo pipefail
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PASS=0
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FAIL=0
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CH0=""
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CH1=""
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CH0_ADDR=""
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CH1_ADDR=""
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if ((EUID == 0)); then
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SUDO=()
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else
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SUDO=(sudo -n)
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if ! "${SUDO[@]}" true 2>/dev/null; then
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echo "Run as root or configure non-interactive sudo." >&2
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exit 2
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fi
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fi
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MODULE_PATH=${MODULE_PATH:-$(modinfo -n i2c-imc-skylake)}
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if [[ ! -r "$MODULE_PATH" ]]; then
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echo "Module not found: $MODULE_PATH" >&2
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exit 2
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fi
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_ok()
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{
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echo "PASS: $*"
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((PASS++)) || true
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}
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_fail()
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{
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echo "FAIL: $*"
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((FAIL++)) || true
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}
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_module_loaded()
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{
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lsmod | awk '$1 == "i2c_imc_skylake" { found = 1 } END { exit !found }'
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}
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_bus()
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{
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local channel=$1
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i2cdetect -l 2>/dev/null | awk -v channel="$channel" '
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tolower($0) ~ /imc.*channel/ && $0 ~ "channel " channel {
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sub(/^i2c-/, "", $1)
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print $1
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exit
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}'
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}
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_find_pci_device()
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{
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local device path vendor
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for path in /sys/bus/pci/devices/*; do
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[[ -r "$path/vendor" && -r "$path/device" ]] || continue
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read -r vendor < "$path/vendor"
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read -r device < "$path/device"
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if [[ "$vendor" == "0x8086" && "$device" == "0x2085" ]]; then
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printf '%s\n' "$path"
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return 0
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fi
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done
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return 1
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}
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_refresh_buses()
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{
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CH0=$(_bus 0)
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CH1=$(_bus 1)
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}
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_scan_spd()
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{
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local bus=$1 result_var=$2
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local address address_hex device readable="" value
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local found=false
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echo "--- SPD scan bus $bus (read-only BYTE_DATA) ---"
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for address in {80..87}; do
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printf -v address_hex '0x%02x' "$address"
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printf -v device '%d-%04x' "$bus" "$address"
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if [[ -L "/sys/bus/i2c/devices/$device/driver" ]]; then
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echo " $address_hex present (bound to $(basename "$(readlink "/sys/bus/i2c/devices/$device/driver")"))"
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found=true
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continue
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fi
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if value=$("${SUDO[@]}" i2cget -y "$bus" "$address_hex" 0x00 2>/dev/null); then
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echo " $address_hex present (reg0=$value)"
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found=true
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readable=${readable:-$address_hex}
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fi
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done
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printf -v "$result_var" '%s' "$readable"
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$found
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}
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_word_test()
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{
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local bus=$1 address=$2
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local byte0 byte1 expected word
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if ! byte0=$("${SUDO[@]}" i2cget -y "$bus" "$address" 0x00 2>/dev/null) ||
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! byte1=$("${SUDO[@]}" i2cget -y "$bus" "$address" 0x01 2>/dev/null) ||
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! word=$("${SUDO[@]}" i2cget -y "$bus" "$address" 0x00 w 2>/dev/null); then
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return 1
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fi
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expected=$((byte0 | (byte1 << 8)))
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((word == expected))
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}
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_nack_test()
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{
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local bus=$1
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local trace
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command -v strace >/dev/null || return 1
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trace=$("${SUDO[@]}" strace -qq -f -e trace=ioctl \
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i2cget -y "$bus" 0x77 0x00 2>&1 || true)
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grep -q '= -1 ENXIO' <<< "$trace"
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}
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_stress_reader()
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{
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local bus=$1 address=$2
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local iteration
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for iteration in {1..100}; do
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"${SUDO[@]}" i2cget -y "$bus" "$address" 0x02 >/dev/null 2>&1 || return 1
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done
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}
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_load_unsafe()
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{
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"${SUDO[@]}" insmod "$MODULE_PATH" allow_unsafe_access=1
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}
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DMESG_START=$("${SUDO[@]}" dmesg | wc -l)
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"${SUDO[@]}" modprobe i2c-dev
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_module_loaded && "${SUDO[@]}" rmmod i2c-imc-skylake
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_load_unsafe
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echo "=== adapter discovery ==="
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_refresh_buses
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[[ -n "$CH0" ]] && _ok "ch0 adapter at i2c-$CH0" || _fail "ch0 adapter not found"
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[[ -n "$CH1" ]] && _ok "ch1 adapter at i2c-$CH1" || _fail "ch1 adapter not found"
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if [[ -n "$CH0" ]]; then
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_scan_spd "$CH0" CH0_ADDR && _ok "SPD device present on ch0" || _fail "no SPD device on ch0"
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fi
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if [[ -n "$CH1" ]]; then
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_scan_spd "$CH1" CH1_ADDR && _ok "SPD device present on ch1" || _fail "no SPD device on ch1"
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fi
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echo "=== transfer semantics ==="
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if [[ -n "$CH0_ADDR" ]]; then
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_word_test "$CH0" "$CH0_ADDR" && _ok "WORD_DATA byte order on ch0" || _fail "WORD_DATA test on ch0"
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fi
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if [[ -n "$CH1_ADDR" ]]; then
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_word_test "$CH1" "$CH1_ADDR" && _ok "WORD_DATA byte order on ch1" || _fail "WORD_DATA test on ch1"
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fi
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if [[ -n "$CH0" ]]; then
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_nack_test "$CH0" && _ok "absent-device ENXIO on ch0" || _fail "expected ENXIO at address 0x77 on ch0"
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fi
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if [[ -n "$CH1" ]]; then
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_nack_test "$CH1" && _ok "absent-device ENXIO on ch1" || _fail "expected ENXIO at address 0x77 on ch1"
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fi
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if [[ -n "$CH0_ADDR" && -n "$CH1_ADDR" ]]; then
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_stress_reader "$CH0" "$CH0_ADDR" &
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pid0=$!
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_stress_reader "$CH1" "$CH1_ADDR" &
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pid1=$!
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stress_ok=true
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wait "$pid0" || stress_ok=false
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wait "$pid1" || stress_ok=false
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$stress_ok && _ok "concurrent 100-read stress on both channels" || _fail "concurrent read stress"
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fi
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echo "=== safe default and targeted udev event ==="
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PCI_DEVICE=$(_find_pci_device) || {
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_fail "PCI device 8086:2085 not found"
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PCI_DEVICE=""
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}
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if [[ -n "$PCI_DEVICE" ]]; then
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"${SUDO[@]}" rmmod i2c-imc-skylake
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"${SUDO[@]}" insmod "$MODULE_PATH"
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_refresh_buses
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if [[ -z "$CH0" && -z "$CH1" ]]; then
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_ok "default-off gate rejected bind without opt-in"
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else
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_fail "driver bound without allow_unsafe_access=1"
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fi
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_module_loaded && "${SUDO[@]}" rmmod i2c-imc-skylake
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if "${SUDO[@]}" udevadm trigger --action=add "$PCI_DEVICE" &&
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"${SUDO[@]}" udevadm settle --timeout=5; then
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_ok "targeted PCI udev event completed"
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else
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_fail "targeted PCI udev event failed"
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fi
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_module_loaded && "${SUDO[@]}" rmmod i2c-imc-skylake
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_load_unsafe
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fi
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echo "=== load/unload x20 ==="
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for iteration in {1..20}; do
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"${SUDO[@]}" rmmod i2c-imc-skylake
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_load_unsafe
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echo " cycle $iteration OK"
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done
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_ok "20 load/unload cycles completed"
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echo "=== kernel messages produced by this test ==="
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NEW_DMESG=$("${SUDO[@]}" dmesg | tail -n "+$((DMESG_START + 1))")
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RELEVANT_DMESG=$(grep -Ei 'i2c-imc-skylake [0-9a-f]{4}:|BUG:|WARNING:|Oops:|KASAN:|lockdep' <<< "$NEW_DMESG" || true)
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printf '%s\n' "$RELEVANT_DMESG"
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if grep -Eiq 'BUG:|WARNING:|Oops:|KASAN:|lockdep' <<< "$NEW_DMESG"; then
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_fail "kernel warning/oops detected"
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else
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_ok "no kernel warning/oops detected"
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fi
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# The driver compares the command registers before and after every transfer.
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# A hit here means firmware, a BMC or CLTT is driving the same engine, which
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# invalidates every other result in this run.
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if grep -q 'another master is using the engine' <<< "$NEW_DMESG"; then
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_fail "foreign master detected on the engine; do not use this system"
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else
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_ok "no foreign master detected during the test"
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fi
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# Likewise for a command the engine never accepted: that path exists because
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# the done bits are latched and must not be mistaken for a fresh completion.
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if grep -q 'command not accepted' <<< "$NEW_DMESG"; then
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_fail "engine did not accept a command; config access path is unreliable"
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else
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_ok "every command was accepted by the engine"
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fi
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echo "=== result: $PASS passed, $FAIL failed ==="
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((FAIL == 0))
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