From d4c378e059443dbaaaece02a0f5148db62bd4484 Mon Sep 17 00:00:00 2001
From: Felipe Balbi <febalbi@microsoft.com>
Date: Fri, 11 Apr 2025 14:28:59 -0700
Subject: Add embassy-imxrt CRC driver

---
 embassy-imxrt/src/crc.rs | 190 +++++++++++++++++++++++++++++++++++++++++++++++
 embassy-imxrt/src/lib.rs |   1 +
 2 files changed, 191 insertions(+)
 create mode 100644 embassy-imxrt/src/crc.rs

(limited to 'embassy-imxrt')

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;
 
-- 
cgit