fingerprintd/tests/Sensor/main.cpp

// SPDX-License-Identifier: GPL-3.0-only
// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®

// lint-disable-file fixed-width-types
/*
Fingerprintd:Sensor unit tests.

Mostly one thing. gpio8-11 are the fingerprint SPI pads, they are
XPU-protected, and touching one from the normal world is not an error return --
it is an immediate SError and the phone reboots where it stands. Mainline's DTS
reserves the range but a userspace chardev request never consults that, so the
guard is ours and it is worth a test that spells out every pin.
*/
import std;
import Fingerprintd;

using namespace fingerprintd::sensor;

namespace {
    int Failures = 0;
    void Check(bool cond, std::string_view msg) {
        if (!cond) {
            std::println(std::cerr, "FAIL: {}", msg);
            ++Failures;
        }
    }
}

int main() {
    // ---- The XPU-protected range, pin by pin
    Check(IsReserved(8) && IsReserved(9) && IsReserved(10) && IsReserved(11),
          "gpio8-11 are all reserved");
    Check(!IsReserved(7), "gpio7 is below the range");
    Check(!IsReserved(12), "gpio12 is above it");
    Check(ReservedSpiFirst == 8 && ReservedSpiCount == 4,
          "the range matches the DTS gpio-reserved-ranges = <8 4>");

    for (unsigned l = 8; l <= 11; l++)
        Check(!IsSafeLine(l), std::format("gpio{} must never be opened", l));

    // ---- Every line we own is outside it
    for (unsigned l : OwnedLines)
        Check(IsSafeLine(l), std::format("owned line gpio{} is safe", l));
    Check(OwnedLines.size() == 3, "three lines: power, reset, irq");

    // ---- The pins themselves, from the stock device tree
    Check(PowerLine == 29, "vdd-gpio = <&tlmm 29>");
    Check(ResetLine == 74, "reset-gpio = <&tlmm 74>");
    Check(IrqLine == 75, "irq-gpio = <&tlmm 75>");
    Check(PowerLine != ResetLine && ResetLine != IrqLine && PowerLine != IrqLine,
          "the three are distinct");

    // The vendor calls it FPS_INT_N but the DT says edge-rising: it idles low
    // and pulses high. Reading it as active-low sees the finger backwards.
    Check(IrqIsActiveHigh, "the interrupt is active high despite the _N");

    // ---- The chip is found by label
    //
    // The chardev reports the DT unit address, not the binding's name. "tlmm"
    // is what every DT reference calls it and matching on that finds nothing.
    Check(ChipLabel == "f100000.pinctrl", "TLMM advertises its DT unit address");
    Check(ChipLabel != "tlmm", "the binding name is not the chardev label");
    Check(!ChipLabel.empty(), "never an index: /dev/gpiochipN is not stable");

    // The line-count check has to actually exclude the other pinctrl on this
    // SoC, which has 23 lines, while admitting TLMM's 168.
    Check(MinChipLines > IrqLine, "a valid chip can contain every line we open");
    Check(MinChipLines > 23, "excludes the 23-line 3440000.pinctrl");
    Check(MinChipLines <= 168, "admits TLMM");

    // ---- Sequencing
    Check(PowerSettle > ResetSettle, "the rail gets the longer settle");
    Check(PowerSettle.count() == 250 && ResetSettle.count() == 50, "the proven delays");
    Check(AssertResetBeforePower, "a warm restart starts from the cold state");

    // ---- The reason the daemon owns the rail at all
    Check(RcDeviceNotFound == -205,
          "a second init in one power cycle answers -205, so recovery is a power cycle");

    if (Failures == 0) std::println("Sensor: all tests passed");
    return Failures;
}