diff --git a/drivers/src/io/mmio.rs b/drivers/src/io/mmio.rs
index 32bc81f5..dde61f0b 100644
--- a/drivers/src/io/mmio.rs
+++ b/drivers/src/io/mmio.rs
@@ -1,12 +1,10 @@
-use core::mem::MaybeUninit;
+use super::Io;
 use core::ops::{BitAnd, BitOr, Not};
 
-use super::Io;
-
+// 主存映射 I/O。
+/// Memory-mapped I/O.
 #[repr(transparent)]
-pub struct Mmio<T> {
-    value: MaybeUninit<T>,
-}
+pub struct Mmio<T>(T);
 
 impl<T> Mmio<T> {
     /// # Safety
@@ -25,9 +23,7 @@ impl<T> Mmio<T> {
     }
 
     pub fn add<'a>(&self, offset: usize) -> &'a mut Self {
-        unsafe {
-            Self::from_base(self.value.as_ptr() as usize + offset * core::mem::size_of::<T>())
-        }
+        unsafe { Self::from_base((&self.0 as *const T).add(offset) as _) }
     }
 }
 
@@ -38,10 +34,19 @@ where
     type Value = T;
 
     fn read(&self) -> T {
-        unsafe { core::ptr::read_volatile(self.value.as_ptr()) }
+        unsafe {
+            let val = core::ptr::read_volatile(&self.0 as *const _);
+            #[cfg(any(target_arch = "riscv32", target_arch = "riscv64"))]
+            core::arch::asm!("fence i,r");
+            val
+        }
     }
 
     fn write(&mut self, value: T) {
-        unsafe { core::ptr::write_volatile(self.value.as_mut_ptr(), value) };
+        unsafe {
+            #[cfg(any(target_arch = "riscv32", target_arch = "riscv64"))]
+            core::arch::asm!("fence w,o");
+            core::ptr::write_volatile(&mut self.0 as *mut _, value)
+        };
     }
 }
diff --git a/drivers/src/io/mod.rs b/drivers/src/io/mod.rs
index 99a5ff31..4afcc0fe 100644
--- a/drivers/src/io/mod.rs
+++ b/drivers/src/io/mod.rs
@@ -1,57 +1,79 @@
-//! General MMIO and PIO device driver.
+// 封装对外设地址空间的访问，包括内存映射 IO 和端口映射 IO。
+//
+// 要了解这两种访问外设的方式，查看[维基百科](https://en.wikipedia.org/wiki/Memory-mapped_I/O)。
+//! Peripheral address space access, including memory-mapped IO and port-mapped IO.
+//!
+//! About these two methods of performing I/O, see [wikipedia](https://en.wikipedia.org/wiki/Memory-mapped_I/O).
 
 use core::ops::{BitAnd, BitOr, Not};
 
 mod mmio;
 #[cfg(target_arch = "x86_64")]
-mod pio;
+mod pmio;
 
 pub use mmio::Mmio;
 #[cfg(target_arch = "x86_64")]
-pub use pio::Pio;
+pub use pmio::Pmio;
 
+// 用于处理外设地址空间访问的接口。
+/// An interface for dealing with device address space access.
 pub trait Io {
+    // 可访问的对象的类型。
+    /// The type of object to access.
     type Value: Copy
         + BitAnd<Output = Self::Value>
         + BitOr<Output = Self::Value>
         + Not<Output = Self::Value>;
 
+    // 从外设读取值。
+    /// Reads value from device.
     fn read(&self) -> Self::Value;
+
+    // 向外设写入值。
+    /// Writes `value` to device.
     fn write(&mut self, value: Self::Value);
 }
 
+// 外设地址空间的一个只读单元。
+/// A readonly unit in device address space.
 #[repr(transparent)]
-pub struct ReadOnly<I> {
-    inner: I,
-}
+pub struct ReadOnly<I>(I);
 
 impl<I> ReadOnly<I> {
-    pub const fn new(inner: I) -> ReadOnly<I> {
-        ReadOnly { inner }
+    // 构造外设地址空间的一个只读单元。
+    /// Constructs a readonly unit in device address space.
+    pub const fn new(inner: I) -> Self {
+        Self(inner)
     }
 }
 
 impl<I: Io> ReadOnly<I> {
+    // 从外设读取值。
+    /// Reads value from device.
     #[inline(always)]
     pub fn read(&self) -> I::Value {
-        self.inner.read()
+        self.0.read()
     }
 }
 
+// 外设地址空间的一个只写单元。
+/// A write-only unit in device address space.
 #[repr(transparent)]
-pub struct WriteOnly<I> {
-    inner: I,
-}
+pub struct WriteOnly<I>(I);
 
 impl<I> WriteOnly<I> {
-    pub const fn new(inner: I) -> WriteOnly<I> {
-        WriteOnly { inner }
+    // 构造外设地址空间的一个只写单元。
+    /// Constructs a write-only unit in device address space.
+    pub const fn new(inner: I) -> Self {
+        Self(inner)
     }
 }
 
 impl<I: Io> WriteOnly<I> {
+    // 向外设写入值。
+    /// Writes `value` to device.
     #[inline(always)]
     pub fn write(&mut self, value: I::Value) {
-        self.inner.write(value)
+        self.0.write(value);
     }
 }
diff --git a/drivers/src/io/pio.rs b/drivers/src/io/pmio.rs
similarity index 68%
rename from drivers/src/io/pio.rs
rename to drivers/src/io/pmio.rs
index 47fa8f86..e3e9a0cf 100644
--- a/drivers/src/io/pio.rs
+++ b/drivers/src/io/pmio.rs
@@ -1,30 +1,35 @@
-use core::arch::asm;
-use core::marker::PhantomData;
+// 端口映射 I/O。
+//! Port-mapped I/O.
 
 use super::Io;
+use core::{arch::asm, marker::PhantomData};
 
-/// Generic PIO
+// 端口映射 I/O。
+/// Port-mapped I/O.
 #[derive(Copy, Clone)]
-pub struct Pio<T> {
+pub struct Pmio<T> {
     port: u16,
     _phantom: PhantomData<T>,
 }
 
-impl<T> Pio<T> {
-    /// Create a PIO from a given port
+impl<T> Pmio<T> {
+    // 映射指定端口进行外设访问。
+    /// Maps a given port to assess device.
     pub const fn new(port: u16) -> Self {
-        Pio::<T> {
+        Self {
             port,
             _phantom: PhantomData,
         }
     }
 }
 
-/// Read/Write for byte PIO
-impl Io for Pio<u8> {
+// 逐字节端口映射读写。
+/// Read/Write for byte PMIO.
+impl Io for Pmio<u8> {
     type Value = u8;
 
-    /// Read
+    // 读。
+    /// Read.
     #[inline(always)]
     fn read(&self) -> u8 {
         let value: u8;
@@ -34,7 +39,8 @@ impl Io for Pio<u8> {
         value
     }
 
-    /// Write
+    // 写。
+    /// Write.
     #[inline(always)]
     fn write(&mut self, value: u8) {
         unsafe {
@@ -43,11 +49,13 @@ impl Io for Pio<u8> {
     }
 }
 
-/// Read/Write for word PIO
-impl Io for Pio<u16> {
+// 逐字端口映射读写。
+/// Read/Write for word PMIO.
+impl Io for Pmio<u16> {
     type Value = u16;
 
-    /// Read
+    // 读。
+    /// Read.
     #[inline(always)]
     fn read(&self) -> u16 {
         let value: u16;
@@ -57,7 +65,8 @@ impl Io for Pio<u16> {
         value
     }
 
-    /// Write
+    // 写。
+    /// Write.
     #[inline(always)]
     fn write(&mut self, value: u16) {
         unsafe {
@@ -66,11 +75,13 @@ impl Io for Pio<u16> {
     }
 }
 
-/// Read/Write for doubleword PIO
-impl Io for Pio<u32> {
+// 逐双字端口映射读写。
+/// Read/Write for double-word PMIO.
+impl Io for Pmio<u32> {
     type Value = u32;
 
-    /// Read
+    // 读。
+    /// Read.
     #[inline(always)]
     fn read(&self) -> u32 {
         let value: u32;
@@ -80,7 +91,8 @@ impl Io for Pio<u32> {
         value
     }
 
-    /// Write
+    // 写。
+    /// Write.
     #[inline(always)]
     fn write(&mut self, value: u32) {
         unsafe {
diff --git a/drivers/src/irq/riscv_plic.rs b/drivers/src/irq/riscv_plic.rs
index 42f3999e..8933de4f 100644
--- a/drivers/src/irq/riscv_plic.rs
+++ b/drivers/src/irq/riscv_plic.rs
@@ -38,8 +38,7 @@ impl PlicUnlocked {
         let hart_id = cpu_id() as usize;
         let mmio = self
             .enable_base
-            .add(PLIC_ENABLE_HART_OFFSET * hart_id)
-            .add(irq_num / 32);
+            .add(PLIC_ENABLE_HART_OFFSET * hart_id + irq_num / 32);
 
         let mask = 1 << (irq_num % 32);
         if enable {
@@ -54,8 +53,7 @@ impl PlicUnlocked {
         let hart_id = cpu_id() as usize;
         let irq_num = self
             .context_base
-            .add(PLIC_CONTEXT_CLAIM_HART_OFFSET * hart_id)
-            .add(PLIC_CONTEXT_CLAIM)
+            .add(PLIC_CONTEXT_CLAIM_HART_OFFSET * hart_id + PLIC_CONTEXT_CLAIM)
             .read() as usize;
         if irq_num == 0 {
             None
@@ -69,8 +67,7 @@ impl PlicUnlocked {
         debug_assert!(IRQ_RANGE.contains(&irq_num));
         let hart_id = cpu_id() as usize;
         self.context_base
-            .add(PLIC_CONTEXT_CLAIM)
-            .add(PLIC_CONTEXT_CLAIM_HART_OFFSET * hart_id)
+            .add(PLIC_CONTEXT_CLAIM + PLIC_CONTEXT_CLAIM_HART_OFFSET * hart_id)
             .write(irq_num as _);
     }
 
@@ -84,8 +81,7 @@ impl PlicUnlocked {
     fn set_threshold(&mut self, threshold: u8) {
         let hart_id = cpu_id() as usize;
         self.context_base
-            .add(PLIC_PRIORITY_HART_OFFSET * hart_id)
-            .add(PLIC_CONTEXT_THRESHOLD)
+            .add(PLIC_PRIORITY_HART_OFFSET * hart_id + PLIC_CONTEXT_THRESHOLD)
             .write(threshold as _);
     }
 
diff --git a/drivers/src/uart/mod.rs b/drivers/src/uart/mod.rs
index 52f8cb94..a805b0d3 100644
--- a/drivers/src/uart/mod.rs
+++ b/drivers/src/uart/mod.rs
@@ -7,4 +7,4 @@ pub use buffered::BufferedUart;
 pub use uart_16550::Uart16550Mmio;
 
 #[cfg(target_arch = "x86_64")]
-pub use uart_16550::Uart16550Pio;
+pub use uart_16550::Uart16550Pmio;
diff --git a/drivers/src/uart/uart_16550.rs b/drivers/src/uart/uart_16550.rs
index 9061d9d5..2662715e 100644
--- a/drivers/src/uart/uart_16550.rs
+++ b/drivers/src/uart/uart_16550.rs
@@ -201,21 +201,21 @@ impl Uart16550Mmio<u32> {
 }
 
 #[cfg(target_arch = "x86_64")]
-mod pio {
+mod pmio {
     use super::*;
-    use crate::io::Pio;
+    use crate::io::Pmio;
 
-    /// PIO driver for UART 16550
-    pub struct Uart16550Pio {
-        inner: Mutex<Uart16550Inner<Pio<u8>>>,
+    /// Pmio driver for UART 16550
+    pub struct Uart16550Pmio {
+        inner: Mutex<Uart16550Inner<Pmio<u8>>>,
         listener: EventListener,
     }
 
-    impl_event_scheme!(Uart16550Pio);
+    impl_event_scheme!(Uart16550Pmio);
 
-    impl Scheme for Uart16550Pio {
+    impl Scheme for Uart16550Pmio {
         fn name(&self) -> &str {
-            "uart16550-pio"
+            "uart16550-Pmio"
         }
 
         fn handle_irq(&self, _irq_num: usize) {
@@ -223,7 +223,7 @@ mod pio {
         }
     }
 
-    impl UartScheme for Uart16550Pio {
+    impl UartScheme for Uart16550Pmio {
         fn try_recv(&self) -> DeviceResult<Option<u8>> {
             self.inner.lock().try_recv()
         }
@@ -237,17 +237,17 @@ mod pio {
         }
     }
 
-    impl Uart16550Pio {
-        /// Construct a `Uart16550Pio` whose address starts at `base`.
+    impl Uart16550Pmio {
+        /// Construct a `Uart16550Pmio` whose address starts at `base`.
         pub fn new(base: u16) -> Self {
-            let mut uart = Uart16550Inner::<Pio<u8>> {
-                data: Pio::new(base),
-                int_en: Pio::new(base + 1),
-                fifo_ctrl: Pio::new(base + 2),
-                line_ctrl: Pio::new(base + 3),
-                modem_ctrl: Pio::new(base + 4),
-                line_sts: ReadOnly::new(Pio::new(base + 5)),
-                modem_sts: ReadOnly::new(Pio::new(base + 6)),
+            let mut uart = Uart16550Inner::<Pmio<u8>> {
+                data: Pmio::new(base),
+                int_en: Pmio::new(base + 1),
+                fifo_ctrl: Pmio::new(base + 2),
+                line_ctrl: Pmio::new(base + 3),
+                modem_ctrl: Pmio::new(base + 4),
+                line_sts: ReadOnly::new(Pmio::new(base + 5)),
+                modem_sts: ReadOnly::new(Pmio::new(base + 6)),
             };
             uart.init();
             Self {
@@ -259,4 +259,4 @@ mod pio {
 }
 
 #[cfg(target_arch = "x86_64")]
-pub use pio::Uart16550Pio;
+pub use pmio::Uart16550Pmio;
diff --git a/kernel-hal/src/bare/arch/x86_64/cpu.rs b/kernel-hal/src/bare/arch/x86_64/cpu.rs
index 2ccd3abd..5d802d96 100644
--- a/kernel-hal/src/bare/arch/x86_64/cpu.rs
+++ b/kernel-hal/src/bare/arch/x86_64/cpu.rs
@@ -26,8 +26,8 @@ hal_fn_impl! {
         fn reset() -> ! {
             info!("shutdown...");
             loop {
-                use zcore_drivers::io::{Io, Pio};
-                Pio::<u16>::new(0x604).write(0x2000);
+                use zcore_drivers::io::{Io, Pmio};
+                Pmio::<u16>::new(0x604).write(0x2000);
                 super::interrupt::wait_for_interrupt();
             }
         }
diff --git a/kernel-hal/src/bare/arch/x86_64/drivers.rs b/kernel-hal/src/bare/arch/x86_64/drivers.rs
index aefcd7bc..e8b1834a 100644
--- a/kernel-hal/src/bare/arch/x86_64/drivers.rs
+++ b/kernel-hal/src/bare/arch/x86_64/drivers.rs
@@ -3,16 +3,16 @@ use alloc::{boxed::Box, sync::Arc};
 use zcore_drivers::bus::pci;
 use zcore_drivers::irq::x86::Apic;
 use zcore_drivers::scheme::IrqScheme;
-use zcore_drivers::uart::{BufferedUart, Uart16550Pio};
+use zcore_drivers::uart::{BufferedUart, Uart16550Pmio};
 use zcore_drivers::{Device, DeviceResult};
 
 use super::trap;
 use crate::drivers;
 
 pub(super) fn init_early() -> DeviceResult {
-    let uart = Arc::new(Uart16550Pio::new(0x3F8));
+    let uart = Arc::new(Uart16550Pmio::new(0x3F8));
     drivers::add_device(Device::Uart(BufferedUart::new(uart)));
-    let uart = Arc::new(Uart16550Pio::new(0x2F8));
+    let uart = Arc::new(Uart16550Pmio::new(0x2F8));
     drivers::add_device(Device::Uart(BufferedUart::new(uart)));
     Ok(())
 }
diff --git a/kernel-hal/src/bare/arch/x86_64/special.rs b/kernel-hal/src/bare/arch/x86_64/special.rs
index c472fb8e..d41faf1f 100644
--- a/kernel-hal/src/bare/arch/x86_64/special.rs
+++ b/kernel-hal/src/bare/arch/x86_64/special.rs
@@ -1,6 +1,6 @@
 //! Functions only available on x86 platforms.
 
-pub use zcore_drivers::io::{Io, Pio};
+pub use zcore_drivers::io::{Io, Pmio};
 
 /// Get physical address of `acpi_rsdp` and `smbios` on x86_64.
 pub fn pc_firmware_tables() -> (u64, u64) {
diff --git a/zircon-object/src/dev/pci/bus.rs b/zircon-object/src/dev/pci/bus.rs
index f7239ebc..56054ef4 100644
--- a/zircon-object/src/dev/pci/bus.rs
+++ b/zircon-object/src/dev/pci/bus.rs
@@ -3,7 +3,7 @@ use super::nodes::{
     SharedLegacyIrqHandler,
 };
 use super::{
-    config::PciConfig, constants::*, pci_init_args::PciIrqSwizzleLut, pio::pci_bdf_raw_addr,
+    config::PciConfig, constants::*, pci_init_args::PciIrqSwizzleLut, pmio::pci_bdf_raw_addr,
     MappedEcamRegion, PciAddrSpace, PciEcamRegion,
 };
 use crate::dev::Interrupt;
@@ -447,9 +447,9 @@ impl PCIeAddressProvider for MmioPcieAddressProvider {
 
 /// Systems that have PIO mapped Config Spaces.
 #[derive(Default)]
-pub struct PioPcieAddressProvider;
+pub struct PmioPcieAddressProvider;
 
-impl PCIeAddressProvider for PioPcieAddressProvider {
+impl PCIeAddressProvider for PmioPcieAddressProvider {
     fn create_config(&self, addr: u64) -> Arc<PciConfig> {
         Arc::new(PciConfig {
             addr_space: PciAddrSpace::PIO,
diff --git a/zircon-object/src/dev/pci/config.rs b/zircon-object/src/dev/pci/config.rs
index af08a9d3..7f70ad1b 100644
--- a/zircon-object/src/dev/pci/config.rs
+++ b/zircon-object/src/dev/pci/config.rs
@@ -1,4 +1,4 @@
-use super::pio::{pio_config_read_addr, pio_config_write_addr};
+use super::pmio::{pmio_config_read_addr, pmio_config_write_addr};
 use super::PciAddrSpace;
 use numeric_enum_macro::numeric_enum;
 
@@ -14,21 +14,21 @@ impl PciConfig {
         trace!("read8 @ {:#x?}", offset);
         match self.addr_space {
             PciAddrSpace::MMIO => unsafe { u8::from_le(*(offset as *const u8)) },
-            PciAddrSpace::PIO => pio_config_read_addr(offset as u32, 8).unwrap() as u8,
+            PciAddrSpace::PIO => pmio_config_read_addr(offset as u32, 8).unwrap() as u8,
         }
     }
     pub fn read16_offset(&self, addr: usize) -> u16 {
         trace!("read16 @ {:#x?}", addr);
         match self.addr_space {
             PciAddrSpace::MMIO => unsafe { u16::from_le(*(addr as *const u16)) },
-            PciAddrSpace::PIO => pio_config_read_addr(addr as u32, 16).unwrap() as u16,
+            PciAddrSpace::PIO => pmio_config_read_addr(addr as u32, 16).unwrap() as u16,
         }
     }
     pub fn read32_offset(&self, addr: usize) -> u32 {
         trace!("read32 @ {:#x?}", addr);
         match self.addr_space {
             PciAddrSpace::MMIO => unsafe { u32::from_le(*(addr as *const u32)) },
-            PciAddrSpace::PIO => pio_config_read_addr(addr as u32, 32).unwrap(),
+            PciAddrSpace::PIO => pmio_config_read_addr(addr as u32, 32).unwrap(),
         }
     }
     pub fn read8(&self, addr: PciReg8) -> u8 {
@@ -56,7 +56,7 @@ impl PciConfig {
     pub fn write8_offset(&self, addr: usize, val: u8) {
         match self.addr_space {
             PciAddrSpace::MMIO => unsafe { *(addr as *mut u8) = val },
-            PciAddrSpace::PIO => pio_config_write_addr(addr as u32, val as u32, 8).unwrap(),
+            PciAddrSpace::PIO => pmio_config_write_addr(addr as u32, val as u32, 8).unwrap(),
         }
     }
     pub fn write16_offset(&self, addr: usize, val: u16) {
@@ -67,13 +67,13 @@ impl PciConfig {
         );
         match self.addr_space {
             PciAddrSpace::MMIO => unsafe { *(addr as *mut u16) = val },
-            PciAddrSpace::PIO => pio_config_write_addr(addr as u32, val as u32, 16).unwrap(),
+            PciAddrSpace::PIO => pmio_config_write_addr(addr as u32, val as u32, 16).unwrap(),
         }
     }
     pub fn write32_offset(&self, addr: usize, val: u32) {
         match self.addr_space {
             PciAddrSpace::MMIO => unsafe { *(addr as *mut u32) = val },
-            PciAddrSpace::PIO => pio_config_write_addr(addr as u32, val as u32, 32).unwrap(),
+            PciAddrSpace::PIO => pmio_config_write_addr(addr as u32, val as u32, 32).unwrap(),
         }
     }
     pub fn write8(&self, addr: PciReg8, val: u8) {
diff --git a/zircon-object/src/dev/pci/mod.rs b/zircon-object/src/dev/pci/mod.rs
index 82ae6641..27c8132c 100644
--- a/zircon-object/src/dev/pci/mod.rs
+++ b/zircon-object/src/dev/pci/mod.rs
@@ -5,14 +5,14 @@ mod caps;
 mod config;
 mod nodes;
 pub mod pci_init_args;
-mod pio;
+mod pmio;
 
 pub use self::bus::{
     MmioPcieAddressProvider, PCIeBusDriver, PcieDeviceInfo, PcieDeviceKObject,
-    PioPcieAddressProvider,
+    PmioPcieAddressProvider,
 };
 pub use self::nodes::{IPciNode, PcieIrqMode};
-pub use self::pio::{pio_config_read, pio_config_write};
+pub use self::pmio::{pio_config_read, pio_config_write};
 
 /// Type of PCI address space.
 #[derive(PartialEq, Debug)]
diff --git a/zircon-object/src/dev/pci/pio.rs b/zircon-object/src/dev/pci/pmio.rs
similarity index 72%
rename from zircon-object/src/dev/pci/pio.rs
rename to zircon-object/src/dev/pci/pmio.rs
index 73d03076..4c023a1f 100644
--- a/zircon-object/src/dev/pci/pio.rs
+++ b/zircon-object/src/dev/pci/pmio.rs
@@ -12,7 +12,7 @@ pub fn pci_bdf_raw_addr(bus: u8, dev: u8, func: u8, offset: u8) -> u32 {
 
 cfg_if::cfg_if! {
 if #[cfg(all(target_arch = "x86_64", target_os = "none"))] {
-    use kernel_hal::x86_64::{Io, Pio};
+    use kernel_hal::x86_64::{Io, Pmio};
     use spin::Mutex;
 
     static PIO_LOCK: Mutex<()> = Mutex::new(());
@@ -20,9 +20,9 @@ if #[cfg(all(target_arch = "x86_64", target_os = "none"))] {
     const PCI_CONFIG_DATA: u16 = 0xcfc;
     const PCI_CONFIG_ENABLE: u32 = 1 << 31;
 
-    pub fn pio_config_read_addr(addr: u32, width: usize) -> ZxResult<u32> {
-        let mut port_cfg = Pio::<u32>::new(PCI_CONFIG_ADDR);
-        let port_data = Pio::<u32>::new(PCI_CONFIG_DATA);
+    pub fn pmio_config_read_addr(addr: u32, width: usize) -> ZxResult<u32> {
+        let mut port_cfg = Pmio::<u32>::new(PCI_CONFIG_ADDR);
+        let port_data = Pmio::<u32>::new(PCI_CONFIG_DATA);
 
         let _lock = PIO_LOCK.lock();
         let shift = ((addr & 0x3) << 3) as usize;
@@ -33,9 +33,9 @@ if #[cfg(all(target_arch = "x86_64", target_os = "none"))] {
         let tmp_val = u32::from_le(port_data.read());
         Ok((tmp_val >> shift) & (((1u64 << width) - 1) as u32))
     }
-    pub fn pio_config_write_addr(addr: u32, val: u32, width: usize) -> ZxResult {
-        let mut port_cfg = Pio::<u32>::new(PCI_CONFIG_ADDR);
-        let mut port_data = Pio::<u32>::new(PCI_CONFIG_DATA);
+    pub fn pmio_config_write_addr(addr: u32, val: u32, width: usize) -> ZxResult {
+        let mut port_cfg = Pmio::<u32>::new(PCI_CONFIG_ADDR);
+        let mut port_data = Pmio::<u32>::new(PCI_CONFIG_DATA);
 
         let _lock = PIO_LOCK.lock();
         let shift = ((addr & 0x3) << 3) as usize;
@@ -54,17 +54,17 @@ if #[cfg(all(target_arch = "x86_64", target_os = "none"))] {
         Ok(())
     }
 } else {
-    pub fn pio_config_read_addr(_addr: u32, _width: usize) -> ZxResult<u32> {
+    pub fn pmio_config_read_addr(_addr: u32, _width: usize) -> ZxResult<u32> {
         Err(ZxError::NOT_SUPPORTED)
     }
-    pub fn pio_config_write_addr(_addr: u32, _val: u32, _width: usize) -> ZxResult {
+    pub fn pmio_config_write_addr(_addr: u32, _val: u32, _width: usize) -> ZxResult {
         Err(ZxError::NOT_SUPPORTED)
     }
 }
 } // cfg_if!
 
 pub fn pio_config_read(bus: u8, dev: u8, func: u8, offset: u8, width: usize) -> ZxResult<u32> {
-    pio_config_read_addr(pci_bdf_raw_addr(bus, dev, func, offset), width)
+    pmio_config_read_addr(pci_bdf_raw_addr(bus, dev, func, offset), width)
 }
 
 pub fn pio_config_write(
@@ -75,5 +75,5 @@ pub fn pio_config_write(
     val: u32,
     width: usize,
 ) -> ZxResult {
-    pio_config_write_addr(pci_bdf_raw_addr(bus, dev, func, offset), val, width)
+    pmio_config_write_addr(pci_bdf_raw_addr(bus, dev, func, offset), val, width)
 }
diff --git a/zircon-syscall/src/pci.rs b/zircon-syscall/src/pci.rs
index c11b00d4..3692faff 100644
--- a/zircon-syscall/src/pci.rs
+++ b/zircon-syscall/src/pci.rs
@@ -6,7 +6,7 @@ use zircon_object::{
         constants::*,
         pci_init_args::{PciInitArgsAddrWindows, PciInitArgsHeader, PCI_INIT_ARG_MAX_SIZE},
         MmioPcieAddressProvider, PCIeBusDriver, PciAddrSpace, PciEcamRegion, PcieDeviceInfo,
-        PcieDeviceKObject, PcieIrqMode, PioPcieAddressProvider,
+        PcieDeviceKObject, PcieIrqMode, PmioPcieAddressProvider,
     },
     dev::{Resource, ResourceKind},
     vm::{pages, VmObject},
@@ -143,7 +143,7 @@ impl Syscall<'_> {
             })?;
             PCIeBusDriver::set_address_translation_provider(addr_provider)?;
         } else if addr_win.cfg_space_type == PCI_CFG_SPACE_TYPE_PIO {
-            let addr_provider = Arc::new(PioPcieAddressProvider::default());
+            let addr_provider = Arc::new(PmioPcieAddressProvider::default());
             PCIeBusDriver::set_address_translation_provider(addr_provider)?;
         } else {
             return Err(ZxError::INVALID_ARGS);