4 files changed, 367 insertions, 1 deletions

diff --git a/docs/pages/imxrt.adoc b/docs/pages/imxrt.adoc
index adf5218e8..a84fbae03 100644
--- a/docs/pages/imxrt.adoc
+++ b/docs/pages/imxrt.adoc
@@ -9,5 +9,5 @@ The link: link:https://github.com/embassy-rs/embassy/tree/main/embassy-imxrt[Emb
 
 The following peripherals have a HAL implementation at present
 
+* CRC
 * GPIO
-
diff --git a/embassy-imxrt/src/crc.rs b/embassy-imxrt/src/crc.rs
new file mode 100644
index 000000000..24d6ba5bd
--- /dev/null
+++ b/embassy-imxrt/src/crc.rs
@@ -0,0 +1,190 @@
+//! Cyclic Redundancy Check (CRC)
+
+use core::marker::PhantomData;
+
+use crate::clocks::{enable_and_reset, SysconPeripheral};
+pub use crate::pac::crc_engine::mode::CrcPolynomial as Polynomial;
+use crate::{peripherals, Peri, PeripheralType};
+
+/// CRC driver.
+pub struct Crc<'d> {
+    info: Info,
+    _config: Config,
+    _lifetime: PhantomData<&'d ()>,
+}
+
+/// CRC configuration
+pub struct Config {
+    /// Polynomial to be used
+    pub polynomial: Polynomial,
+
+    /// Reverse bit order of input?
+    pub reverse_in: bool,
+
+    /// 1's complement input?
+    pub complement_in: bool,
+
+    /// Reverse CRC bit order?
+    pub reverse_out: bool,
+
+    /// 1's complement CRC?
+    pub complement_out: bool,
+
+    /// CRC Seed
+    pub seed: u32,
+}
+
+impl Config {
+    /// Create a new CRC config.
+    #[must_use]
+    pub fn new(
+        polynomial: Polynomial,
+        reverse_in: bool,
+        complement_in: bool,
+        reverse_out: bool,
+        complement_out: bool,
+        seed: u32,
+    ) -> Self {
+        Config {
+            polynomial,
+            reverse_in,
+            complement_in,
+            reverse_out,
+            complement_out,
+            seed,
+        }
+    }
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self {
+            polynomial: Polynomial::CrcCcitt,
+            reverse_in: false,
+            complement_in: false,
+            reverse_out: false,
+            complement_out: false,
+            seed: 0xffff,
+        }
+    }
+}
+
+impl<'d> Crc<'d> {
+    /// Instantiates new CRC peripheral and initializes to default values.
+    pub fn new<T: Instance>(_peripheral: Peri<'d, T>, config: Config) -> Self {
+        // enable CRC clock
+        enable_and_reset::<T>();
+
+        let mut instance = Self {
+            info: T::info(),
+            _config: config,
+            _lifetime: PhantomData,
+        };
+
+        instance.reconfigure();
+        instance
+    }
+
+    /// Reconfigured the CRC peripheral.
+    fn reconfigure(&mut self) {
+        self.info.regs.mode().write(|w| {
+            w.crc_poly()
+                .variant(self._config.polynomial)
+                .bit_rvs_wr()
+                .variant(self._config.reverse_in)
+                .cmpl_wr()
+                .variant(self._config.complement_in)
+                .bit_rvs_sum()
+                .variant(self._config.reverse_out)
+                .cmpl_sum()
+                .variant(self._config.complement_out)
+        });
+
+        // Init CRC value
+        self.info
+            .regs
+            .seed()
+            .write(|w| unsafe { w.crc_seed().bits(self._config.seed) });
+    }
+
+    /// Feeds a byte into the CRC peripheral. Returns the computed checksum.
+    pub fn feed_byte(&mut self, byte: u8) -> u32 {
+        self.info.regs.wr_data8().write(|w| unsafe { w.bits(byte) });
+
+        self.info.regs.sum().read().bits()
+    }
+
+    /// Feeds an slice of bytes into the CRC peripheral. Returns the computed checksum.
+    pub fn feed_bytes(&mut self, bytes: &[u8]) -> u32 {
+        let (prefix, data, suffix) = unsafe { bytes.align_to::<u32>() };
+
+        for b in prefix {
+            self.info.regs.wr_data8().write(|w| unsafe { w.bits(*b) });
+        }
+
+        for d in data {
+            self.info.regs.wr_data32().write(|w| unsafe { w.bits(*d) });
+        }
+
+        for b in suffix {
+            self.info.regs.wr_data8().write(|w| unsafe { w.bits(*b) });
+        }
+
+        self.info.regs.sum().read().bits()
+    }
+
+    /// Feeds a halfword into the CRC peripheral. Returns the computed checksum.
+    pub fn feed_halfword(&mut self, halfword: u16) -> u32 {
+        self.info.regs.wr_data16().write(|w| unsafe { w.bits(halfword) });
+
+        self.info.regs.sum().read().bits()
+    }
+
+    /// Feeds an slice of halfwords into the CRC peripheral. Returns the computed checksum.
+    pub fn feed_halfwords(&mut self, halfwords: &[u16]) -> u32 {
+        for halfword in halfwords {
+            self.info.regs.wr_data16().write(|w| unsafe { w.bits(*halfword) });
+        }
+
+        self.info.regs.sum().read().bits()
+    }
+
+    /// Feeds a words into the CRC peripheral. Returns the computed checksum.
+    pub fn feed_word(&mut self, word: u32) -> u32 {
+        self.info.regs.wr_data32().write(|w| unsafe { w.bits(word) });
+
+        self.info.regs.sum().read().bits()
+    }
+
+    /// Feeds an slice of words into the CRC peripheral. Returns the computed checksum.
+    pub fn feed_words(&mut self, words: &[u32]) -> u32 {
+        for word in words {
+            self.info.regs.wr_data32().write(|w| unsafe { w.bits(*word) });
+        }
+
+        self.info.regs.sum().read().bits()
+    }
+}
+
+struct Info {
+    regs: crate::pac::CrcEngine,
+}
+
+trait SealedInstance {
+    fn info() -> Info;
+}
+
+/// CRC instance trait.
+#[allow(private_bounds)]
+pub trait Instance: SealedInstance + PeripheralType + SysconPeripheral + 'static + Send {}
+
+impl Instance for peripherals::CRC {}
+
+impl SealedInstance for peripherals::CRC {
+    fn info() -> Info {
+        // SAFETY: safe from single executor
+        Info {
+            regs: unsafe { crate::pac::CrcEngine::steal() },
+        }
+    }
+}
diff --git a/embassy-imxrt/src/lib.rs b/embassy-imxrt/src/lib.rs
index ad9f81e88..d8ce97f76 100644
--- a/embassy-imxrt/src/lib.rs
+++ b/embassy-imxrt/src/lib.rs
@@ -18,6 +18,7 @@ compile_error!(
 pub(crate) mod fmt;
 
 pub mod clocks;
+pub mod crc;
 pub mod gpio;
 pub mod iopctl;
 
diff --git a/examples/mimxrt6/src/bin/crc.rs b/examples/mimxrt6/src/bin/crc.rs
new file mode 100644
index 000000000..005a250e5
--- /dev/null
+++ b/examples/mimxrt6/src/bin/crc.rs
@@ -0,0 +1,175 @@
+#![no_std]
+#![no_main]
+
+extern crate embassy_imxrt_examples;
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_imxrt::crc::{Config, Crc, Polynomial};
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let mut p = embassy_imxrt::init(Default::default());
+    let data = b"123456789";
+
+    info!("Initializing CRC");
+
+    // CRC-CCITT
+    let mut crc = Crc::new(p.CRC.reborrow(), Default::default());
+    let output = crc.feed_bytes(data);
+    defmt::assert_eq!(output, 0x29b1);
+
+    // CRC16-ARC
+    let mut crc = Crc::new(
+        p.CRC.reborrow(),
+        Config {
+            polynomial: Polynomial::Crc16,
+            reverse_in: true,
+            reverse_out: true,
+            complement_out: false,
+            seed: 0,
+            ..Default::default()
+        },
+    );
+    let output = crc.feed_bytes(data);
+    defmt::assert_eq!(output, 0xbb3d);
+
+    // CRC16-CMS
+    let mut crc = Crc::new(
+        p.CRC.reborrow(),
+        Config {
+            polynomial: Polynomial::Crc16,
+            reverse_in: false,
+            reverse_out: false,
+            complement_out: false,
+            seed: 0xffff,
+            ..Default::default()
+        },
+    );
+    let output = crc.feed_bytes(data);
+    defmt::assert_eq!(output, 0xaee7);
+
+    // CRC16-DDS-110
+    let mut crc = Crc::new(
+        p.CRC.reborrow(),
+        Config {
+            polynomial: Polynomial::Crc16,
+            reverse_in: false,
+            reverse_out: false,
+            complement_out: false,
+            seed: 0x800d,
+            ..Default::default()
+        },
+    );
+    let output = crc.feed_bytes(data);
+    defmt::assert_eq!(output, 0x9ecf);
+
+    // CRC16-MAXIM-DOW
+    let mut crc = Crc::new(
+        p.CRC.reborrow(),
+        Config {
+            polynomial: Polynomial::Crc16,
+            reverse_in: true,
+            reverse_out: true,
+            complement_out: true,
+            seed: 0,
+            ..Default::default()
+        },
+    );
+    let output = crc.feed_bytes(data);
+    defmt::assert_eq!(output, 0x44c2);
+
+    // CRC16-MODBUS
+    let mut crc = Crc::new(
+        p.CRC.reborrow(),
+        Config {
+            polynomial: Polynomial::Crc16,
+            reverse_in: true,
+            reverse_out: true,
+            complement_out: false,
+            seed: 0xffff,
+            ..Default::default()
+        },
+    );
+    let output = crc.feed_bytes(data);
+    defmt::assert_eq!(output, 0x4b37);
+
+    // CRC32-BZIP2
+    let mut crc = Crc::new(
+        p.CRC.reborrow(),
+        Config {
+            polynomial: Polynomial::Crc32,
+            reverse_in: false,
+            reverse_out: false,
+            complement_out: true,
+            seed: 0xffff_ffff,
+            ..Default::default()
+        },
+    );
+    let output = crc.feed_bytes(data);
+    defmt::assert_eq!(output, 0xfc89_1918);
+
+    // CRC32-CKSUM
+    let mut crc = Crc::new(
+        p.CRC.reborrow(),
+        Config {
+            polynomial: Polynomial::Crc32,
+            reverse_in: false,
+            reverse_out: false,
+            complement_out: true,
+            seed: 0,
+            ..Default::default()
+        },
+    );
+    let output = crc.feed_bytes(data);
+    defmt::assert_eq!(output, 0x765e_7680);
+
+    // CRC32-ISO-HDLC
+    let mut crc = Crc::new(
+        p.CRC.reborrow(),
+        Config {
+            polynomial: Polynomial::Crc32,
+            reverse_in: true,
+            reverse_out: true,
+            complement_out: true,
+            seed: 0xffff_ffff,
+            ..Default::default()
+        },
+    );
+    let output = crc.feed_bytes(data);
+    defmt::assert_eq!(output, 0xcbf4_3926);
+
+    // CRC32-JAMCRC
+    let mut crc = Crc::new(
+        p.CRC.reborrow(),
+        Config {
+            polynomial: Polynomial::Crc32,
+            reverse_in: true,
+            reverse_out: true,
+            complement_out: false,
+            seed: 0xffff_ffff,
+            ..Default::default()
+        },
+    );
+    let output = crc.feed_bytes(data);
+    defmt::assert_eq!(output, 0x340b_c6d9);
+
+    // CRC32-MPEG-2
+    let mut crc = Crc::new(
+        p.CRC.reborrow(),
+        Config {
+            polynomial: Polynomial::Crc32,
+            reverse_in: false,
+            reverse_out: false,
+            complement_out: false,
+            seed: 0xffff_ffff,
+            ..Default::default()
+        },
+    );
+    let output = crc.feed_bytes(data);
+    defmt::assert_eq!(output, 0x0376_e6e7);
+
+    info!("end program");
+    cortex_m::asm::bkpt();
+}