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.
91 lines
1.8 KiB
Bash
Executable File
91 lines
1.8 KiB
Bash
Executable File
# Shared helpers for the tools/ scripts. Sourced, not executed.
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# shellcheck shell=bash
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PCU_VENDOR_DEVICE=8086:2085
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# Per-channel register offsets in the PCU function's config space.
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REG_CH0_DATA=0x9c
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REG_CH1_DATA=0xa0
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REG_CH0_STAT=0xa8
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REG_CH1_STAT=0xac
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REG_CH0_CTRL=0xb4
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REG_CH1_CTRL=0xb8
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ALL_REGS=(
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"ch0.DATA:$REG_CH0_DATA"
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"ch1.DATA:$REG_CH1_DATA"
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"ch0.STAT:$REG_CH0_STAT"
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"ch1.STAT:$REG_CH1_STAT"
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"ch0.CTRL:$REG_CH0_CTRL"
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"ch1.CTRL:$REG_CH1_CTRL"
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)
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die()
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{
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echo "error: $*" >&2
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exit 1
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}
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require_root()
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{
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((EUID == 0)) || die "run as root"
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}
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require_cmd()
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{
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local cmd
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for cmd in "$@"; do
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command -v "$cmd" >/dev/null || die "missing command: $cmd"
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done
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}
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# Print the domain:bus:dev.fn of the PCU function, or fail.
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find_pcu()
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{
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local bdf
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bdf=$(lspci -Dn -d "$PCU_VENDOR_DEVICE" | awk 'NR == 1 { print $1 }')
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[[ -n "$bdf" ]] || die "PCI function $PCU_VENDOR_DEVICE not found"
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printf '%s\n' "$bdf"
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}
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# read_reg <bdf> <offset> -> 32-bit value as 0x%08x
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read_reg()
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{
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local bdf=$1 off=$2 raw
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raw=$(setpci -s "$bdf" "$off.L") || die "setpci read $off failed"
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printf '0x%08x\n' "$((16#$raw))"
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}
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# Snapshot every engine register into a "name=value" list.
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snapshot_regs()
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{
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local bdf=$1 entry name off
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for entry in "${ALL_REGS[@]}"; do
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name=${entry%%:*}
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off=${entry##*:}
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printf '%s=%s\n' "$name" "$(read_reg "$bdf" "$off")"
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done
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}
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# Sum of MSR_SMI_COUNT (0x34) across all CPUs. Prints -1 if unavailable.
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read_smi_count()
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{
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local cpu total=0 value
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command -v rdmsr >/dev/null || { echo -1; return; }
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for cpu in /dev/cpu/[0-9]*; do
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[[ -e "$cpu/msr" ]] || continue
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value=$(rdmsr -p "${cpu##*/}" -d 0x34 2>/dev/null) || continue
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total=$((total + value))
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done
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printf '%s\n' "$total"
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}
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driver_is_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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