處理驅動程式庫中的中斷

#include <lib/async/cpp/irq.h>

class MyDriver : public fdf::DriverBase {
 public:
  zx::result<> Start() override {
    // Get the interrupt for a GPIO FIDL service.
    zx::result<fidl::ClientEnd<fuchsia_hardware_gpio::Gpio>> gpio =
      incoming()->Connect<fuchsia_hardware_gpio::Service::Device>(kIrqGpioParentName);
    if (gpio.is_error()) {
      fdf::error("Failed to connect to irq gpio: {}", gpio);
      return gpio.take_error();
    }
    fidl::WireResult interrupt = fidl::WireCall(gpio.value())->GetInterrupt({});
    if (!interrupt.ok()) {
      fdf::error("Failed to send GetInterrupt request: {}", interrupt.status_string());
      return zx::error(interrupt.status());
    }
    if (interrupt->is_error()) {
      fdf::error("Failed to get interrupt: {}", zx_status_get_string(interrupt->error_value()));
      return interrupt->take_error();
    }
    interrupt_ = std::move(interrupt->value()->interrupt);

    // Start listening to `interrupt_`. `interrupt_handler_` will execute its
    // associated callback on dispatcher `dispatcher()` when `interrupt_` is
    // triggered.
    interrupt_handler_.set_object(interrupt_.get());
    zx_status_t status = interrupt_handler_.Begin(dispatcher());
    if (status != ZX_OK) {
      fdf::error("Failed to listen to interrupt: {}",
        zx_status_get_string(status));
      return zx::error(status);
    }

    return zx::ok();
  }

 private:
  // Called by `interrupt_handler_` when `interrupt_` is triggered.
  void HandleInterrupt(
    // Dispatcher that `HandleInterrupt()` was executed on.
    async_dispatcher_t* dispatcher,

    // Object that executed `HandleInterrupt()`.
    async::IrqBase* irq,

    // Status of handling the interrupt.
    zx_status_t status,

    // Information related to the interrupt.
    const zx_packet_interrupt_t* interrupt_packet) {

    if (status != ZX_OK) {
      if (status == ZX_ERR_CANCELED) {
        // Expected behavior as this occurs when `interrupt_handler_` is
        // destructed.
        fdf::debug("Interrupt handler cancelled");
      } else {
        fdf::error("Failed to handle interrupt: {}",
          zx_status_get_string(status));
      }

      // An error status means that the interrupt was not triggered so don't
      // handle it.
      return;
    }

    // Wrap the interrupt ack in a defer to ensure that the interrupt is
    // acknowledged even in the case that an error occurs while trying to
    // handle the interrupt.
    auto ack_interrupt = fit::defer([this] {
      // Acknowledge the interrupt. This "re-arms" the interrupt. If the
      // interrupt is not acknowledged then `interrupt_` cannot be triggered
      // again and `HandleInterrupt()` will not get called again.
      interrupt_.ack();
    });

    // Perform work in response to triggered interrupt.
  }

  // Interrupt to listen to.
  zx::interrupt interrupt_;

  // Calls `this->HandleInterrupt()` every time `interrupt_` is triggered.
  // Destructing `interrupt_handler_` means to no longer listen to `interrupt_`.
  async::IrqMethod<MyDriver, &MyDriver::HandleInterrupt> interrupt_handler_{this};
};

zx::interrupt interrupt;
ASSERT_EQ(
  zx::interrupt::create(zx::resource(), 0, ZX_INTERRUPT_VIRTUAL, &interrupt),
  ZX_OK);

zx::interrupt duplicate;
ASSERT_EQ(interrupt.duplicate(ZX_RIGHT_SAME_RIGHTS, &duplicate), ZX_OK);

// Timestamp of when the interrupt was triggered.
zx::clock::get_boot()),

#include <lib/async/cpp/wait.h>

class MyDriverEnvironment : public fdf_testing::Environment {
 public:
  zx::result<> Serve(fdf::OutgoingDirectory& to_driver_vfs) override {
    // Create a virtual interrupt to be listened to by the driver.
    EXPECT_EQ(
      zx::interrupt::create(zx::resource(), 0, ZX_INTERRUPT_VIRTUAL, &interrupt_),
      ZX_OK);


    zx::interrupt duplicate;
    EXPECT_EQ(interrupt_.duplicate(ZX_RIGHT_SAME_RIGHTS, &duplicate), ZX_OK);
    // Send duplicate interrupt to driver.

    // Dispatcher used to execute `HandleInterruptAck()`. In a driver unit test,
    // it is recommended to use the environment dispatcher so that
    // `HandleInterruptAck()` doesn't block the driver's code execution.
    async_dispatcher_t* dispatcher = fdf::Dispatcher::GetCurrent()->async_dispatcher();

    // Listen for when `interrupt_` is acknowledged.
    interrupt_ack_handler_.set_object(interrupt_.get());
    EXPECT_EQ(interrupt_ack_handler_.Begin(dispatcher), ZX_OK);

    return zx::ok();
  }

 private:
  // Called when `interrupt_` receives an acknowledgement.
  void HandleInterruptAck(
    // Dispatcher that `HandleInterruptAck()` was called on.
    async_dispatcher_t* dispatcher,

    // Object responsible for calling `HandleInterruptAck()`.
    async::WaitBase* wait,

    // Status of waiting for the acknowledgement.
    zx_status_t status,

    // Information related to the acknowledgement.
    const zx_packet_signal_t* signal) {

    if (status != ZX_OK) {
        FAIL() << "Failed to wait for interrupt ack" << zx_status_get_string(status);
    }

    // Do something in response to the acknowledgement.

    // "Re-arm" the listener. Wait for the next time `interrupt_` is
    // acknowledged.
    status = wait->Begin(dispatcher);
    if (status != ZX_OK) {
        fdf::error("Failed to re-arm interrupt ack handler: {}", zx_status_get_string(status));
    }
  }

  // Virtual interrupt that the driver is listening to.
  zx::interrupt interrupt_;

  // Calls `HandleInterruptAck()` whenever `interrupt_` receives an
  // acknowledgement.
  async::WaitMethod<InterruptController, &InterruptController::HandleInterruptAck>
    interrupt_ack_handler_{
      // Class instance to call `HandleInterruptAck()` on.
      this,

      // The object that the signals belong to. The test will provide the
      // interrupt object to `interrupt_ack_handler_` after the interrupt is
      // constructed.
      ZX_HANDLE_INVALID,

      // Call the callback when `interrupt_` is in the "untriggered" state.
      ZX_VIRTUAL_INTERRUPT_UNTRIGGERED,

      // Only call `HandleInterruptAck()` if the
      // ZX_VIRTUAL_INTERRUPT_UNTRIGGERED signal was received after
      // `interrupt_ack_handler_.Begin()` was called. If `interrupt_` is already
      // in the "untriggered" state before `interrupt_ack_handler_.Begin()` is
      // called then don't call `HandleInterruptAck()`.
      ZX_WAIT_ASYNC_EDGE
  };
};

class MyDriverTestConfiguration final {
 public:
  using DriverType = MyDriver;
  using EnvironmentType = MyDriverEnvironment;
};

class MyDriverTest : public testing::Test {
 public:
  void SetUp() override {
    ASSERT_EQ(driver_test_.StartDriver().status_value(), ZX_OK);
  }

 private:
  fdf_testing::BackgroundDriverTest<MyDriverTestConfiguration> driver_test_;
};