Add cache maintenance regs and simple API for inner cache maintenance

cortex-ar/CHANGELOG.md

@@ -10,6 +10,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Added
 
 - `dmb` data memory barrier in ASM module.
+- API for inner cache maintenance as part of the new `cache` module. This includes functions to
+  completely clean, invalidate or clean & invalidate the L1 data cache or perform data cache
+  maintenance by MVA (specific address).
 
 ## [v0.2.0]
 

cortex-ar/src/cache.rs

@@ -0,0 +1,108 @@
+use arbitrary_int::u3;
+
+use crate::register::{Dccimvac, Dccisw, Dccmvac, Dccsw, Dcimvac, Dcisw, SysRegWrite};
+
+/// Invalidate the full L1 data cache.
+///
+/// ## Generics
+///
+/// - A: log2(ASSOCIATIVITY) rounded up to the next integer if necessary. For example, a 4-way
+///   associative cache will have a value of 2 and a 8-way associative cache will have a value of
+///   3.
+/// - N: log2(LINE LENGTH). For example, a 32-byte line length (4 words) will have a value of
+///   5.
+/// - S: log2(NUM OF SETS). For systems with a fixed cache size, the number of sets can be
+///   calculated using `CACHE SIZE / (LINE LENGTH * ASSOCIATIVITY)`.
+///   For example, a 4-way associative 32kB L1 cache with a 32-byte line length (4 words) will
+///   have 32768 / (32 * 4) == 256 sets and S will have a value of 8.
+#[inline]
+pub fn invalidate_l1_data_cache<const A: usize, const N: usize, const S: usize>() {
+    let ways = 1 << A;
+    let sets = 1 << S;
+
+    for set in 0..sets {
+        for way in 0..ways {
+            unsafe { Dcisw::write(Dcisw::new::<A, N>(way, set, u3::new(0))) };
+        }
+    }
+}
+
+/// Clean the full L1 data cache.
+///
+/// ## Generics
+///
+/// - A: log2(ASSOCIATIVITY) rounded up to the next integer if necessary. For example, a 4-way
+///   associative cache will have a value of 2 and a 8-way associative cache will have a value of
+///   3.
+/// - N: log2(LINE LENGTH). For example, a 32-byte line length (4 words) will have a value of
+///   5.
+/// - S: log2(NUM OF SETS). For systems with a fixed cache size, the number of sets can be
+///   calculated using `CACHE SIZE / (LINE LENGTH * ASSOCIATIVITY)`.
+///   For example, a 4-way associative 32kB L1 cache with a 32-byte line length (4 words) will
+///   have 32768 / (32 * 4) == 256 sets and S will have a value of 8.
+#[inline]
+pub fn clean_l1_data_cache<const A: usize, const N: usize, const S: usize>() {
+    let ways = 1 << A;
+    let sets = 1 << S;
+
+    for set in 0..sets {
+        for way in 0..ways {
+            unsafe { Dccsw::write(Dccsw::new::<A, N>(way, set, u3::new(0))) };
+        }
+    }
+}
+
+/// Clean and Invalidate the full L1 data cache.
+///
+/// ## Generics
+///
+/// - A: log2(ASSOCIATIVITY) rounded up to the next integer if necessary. For example, a 4-way
+///   associative cache will have a value of 2 and a 8-way associative cache will have a value of
+///   3.
+/// - N: log2(LINE LENGTH). For example, a 32-byte line length (4 words) will have a value of
+///   5.
+/// - S: log2(NUM OF SETS). For systems with a fixed cache size, the number of sets can be
+///   calculated using `CACHE SIZE / (LINE LENGTH * ASSOCIATIVITY)`.
+///   For example, a 4-way associative 32kB L1 cache with a 32-byte line length (4 words) will
+///   have 32768 / (32 * 4) == 256 sets and S will have a value of 8.
+#[inline]
+pub fn clean_and_invalidate_l1_data_cache<const A: usize, const N: usize, const S: usize>() {
+    let ways = 1 << A;
+    let sets = 1 << S;
+
+    for set in 0..sets {
+        for way in 0..ways {
+            unsafe { Dccisw::write(Dccisw::new::<A, N>(way, set, u3::new(0))) };
+        }
+    }
+}
+
+/// Invalidates a data cache line to the point of coherence.
+///
+/// See p.1735 of the ARMv7-A Architecture Reference Manual for more information.
+#[inline]
+pub fn invalidate_data_cache_line_to_poc(addr: u32) {
+    unsafe {
+        Dcimvac::write_raw(addr);
+    }
+}
+
+/// Cleans a data cache line to the point of coherence.
+///
+/// See p.1735 of the ARMv7-A Architecture Reference Manual for more information.
+#[inline]
+pub fn clean_data_cache_line_to_poc(addr: u32) {
+    unsafe {
+        Dccmvac::write_raw(addr);
+    }
+}
+
+/// Cleans and invalidates a data cache line to the point of coherence.
+///
+/// See p.1735 of the ARMv7-A Architecture Reference Manual for more information.
+#[inline]
+pub fn clean_and_invalidate_data_cache_line_to_poc(addr: u32) {
+    unsafe {
+        Dccimvac::write_raw(addr);
+    }
+}

cortex-ar/src/lib.rs

@@ -7,6 +7,7 @@ mod critical_section;
 #[cfg(target_arch = "arm")]
 pub mod asm;
 
+pub mod cache;
 pub mod interrupt;
 pub mod mmu;
 pub mod register;

cortex-ar/src/register/bpiall.rs

@@ -0,0 +1,23 @@
+//! BPIALL: Invalidate all entries from branch predictors
+
+use crate::register::SysReg;
+
+/// BPIALL: Invalidate all entries from branch predictors
+pub struct BpIAll;
+
+impl SysReg for BpIAll {
+    const CP: u32 = 15;
+    const CRN: u32 = 7;
+    const OP1: u32 = 0;
+    const CRM: u32 = 5;
+    const OP2: u32 = 6;
+}
+
+impl crate::register::SysRegWrite for BpIAll {}
+
+impl BpIAll {
+    #[inline]
+    pub fn write() {
+        unsafe { <Self as crate::register::SysRegWrite>::write_raw(0) }
+    }
+}

cortex-ar/src/register/ccsidr.rs

@@ -1,21 +1,42 @@
 //! Code for managing CCSIDR (*Current Cache Size ID Register*)
 
 use crate::register::{SysReg, SysRegRead};
+use arbitrary_int::{u10, u15, u3};
 
 /// CCSIDR (*Current Cache Size ID Register*)
-pub struct Ccsidr(pub u32);
+#[bitbybit::bitfield(u32)]
+#[derive(Debug)]
+pub struct Ccsidr {
+    #[bit(31, rw)]
+    write_through: bool,
+    #[bit(30, rw)]
+    write_back: bool,
+    #[bit(29, rw)]
+    read_alloc: bool,
+    #[bit(28, rw)]
+    write_alloc: bool,
+    #[bits(13..=27, rw)]
+    num_sets: u15,
+    #[bits(3..=12, rw)]
+    associativity: u10,
+    #[bits(0..=2, rw)]
+    line_size: u3,
+}
+
 impl SysReg for Ccsidr {
     const CP: u32 = 15;
     const CRN: u32 = 0;
     const OP1: u32 = 1;
     const CRM: u32 = 0;
     const OP2: u32 = 0;
 }
+
 impl crate::register::SysRegRead for Ccsidr {}
+
 impl Ccsidr {
     #[inline]
     /// Reads CCSIDR (*Current Cache Size ID Register*)
     pub fn read() -> Ccsidr {
-        unsafe { Self(<Self as SysRegRead>::read_raw()) }
+        unsafe { Self::new_with_raw_value(<Self as SysRegRead>::read_raw()) }
     }
 }

cortex-ar/src/register/csselr.rs

@@ -1,9 +1,26 @@
 //! Code for managing CSSELR (*Cache Size Selection Register*)
+use arbitrary_int::u3;
 
 use crate::register::{SysReg, SysRegRead, SysRegWrite};
 
+#[bitbybit::bitenum(u1, exhaustive = true)]
+#[derive(Debug, PartialEq, Eq)]
+pub enum CacheType {
+    DataOrUnified = 0,
+    Instruction = 1,
+}
+
 /// CSSELR (*Cache Size Selection Register*)
-pub struct Csselr(pub u32);
+#[bitbybit::bitfield(u32)]
+#[derive(Debug, PartialEq, Eq)]
+pub struct Csselr {
+    /// 0 for L1 cache, 1 for L2, etc.
+    #[bits(1..=3, rw)]
+    level: u3,
+    #[bit(0, rw)]
+    cache_type: CacheType,
+}
+
 impl SysReg for Csselr {
     const CP: u32 = 15;
     const CRN: u32 = 0;
@@ -16,7 +33,7 @@ impl Csselr {
     #[inline]
     /// Reads CSSELR (*Cache Size Selection Register*)
     pub fn read() -> Csselr {
-        unsafe { Self(<Self as SysRegRead>::read_raw()) }
+        unsafe { Self::new_with_raw_value(<Self as SysRegRead>::read_raw()) }
     }
 }
 impl crate::register::SysRegWrite for Csselr {}
@@ -29,7 +46,7 @@ impl Csselr {
     /// Ensure that this value is appropriate for this register
     pub unsafe fn write(value: Self) {
         unsafe {
-            <Self as SysRegWrite>::write_raw(value.0);
+            <Self as SysRegWrite>::write_raw(value.raw_value());
         }
     }
 }

cortex-ar/src/register/dc_sw_ops.rs

@@ -0,0 +1,38 @@
+use arbitrary_int::u3;
+
+/// Create input data register value for cache maintenance operations by set and way.
+///
+/// ## Generics
+///
+/// - A: log2(ASSOCIATIVITY) rounded up to the next integer if necessary. For example, a 4-way
+///   associative cache will have a value of 2 and a 8-way associative cache will have a value of
+///   4.
+/// - N: log2(LINE LENGTH). For example, a 32-byte line length (4 words) will have a value of
+///   5.
+#[inline]
+pub const fn new<const A: usize, const N: usize>(way: u8, set: u16, level: u3) -> u32 {
+    if A == 0 {
+        ((set as u32) << N) | level.value() as u32
+    } else {
+        ((way as u32) << (32 - A)) | ((set as u32) << N) | level.value() as u32
+    }
+}
+
+/// Create input data register value for cache maintenance operations by set and way.
+/// Returns [None] on invalid input.
+///
+/// # Arguments
+///
+/// - a: log2(ASSOCIATIVITY) rounded up to the next integer if necessary. For example, a 4-way
+///   associative cache will have a value of 2 and a 8-way associative cache will have a value of
+///   4.
+/// - n: log2(LINE LENGTH). For example, a 32-byte line length (4 words) will have a value of
+///   5.
+#[inline]
+pub const fn new_with_offsets(a: usize, way: u8, n: usize, set: u16, level: u3) -> u32 {
+    if a == 0 {
+        ((set as u32) << n) | level.value() as u32
+    } else {
+        ((way as u32) << (32 - a)) | ((set as u32) << n) | level.value() as u32
+    }
+}

cortex-ar/src/register/dccimvac.rs

@@ -0,0 +1,36 @@
+//! DCCIMVAC (*Clean And Invalidate Data Cache Or Unified Cache Line by MVA to Point of Coherence.*)
+use crate::register::{SysReg, SysRegWrite};
+
+pub struct Dccimvac(pub u32);
+
+impl Dccimvac {
+    #[inline]
+    pub const fn new(addr: u32) -> Self {
+        Self(addr)
+    }
+}
+
+impl SysReg for Dccimvac {
+    const CP: u32 = 15;
+    const CRN: u32 = 7;
+    const OP1: u32 = 0;
+    const CRM: u32 = 14;
+    const OP2: u32 = 1;
+}
+
+impl crate::register::SysRegWrite for Dccimvac {}
+
+impl Dccimvac {
+    #[inline]
+    /// Writes DCCIMVAC (*Clean And Invalidate Data Cache Or Unified Cache Line by MVA to Point of Coherence.*)
+    ///
+    /// # Safety
+    ///
+    /// Ensure that this value is appropriate for this register. Generally, the address passed
+    /// to the write call should be aligned to the cache line size.
+    pub unsafe fn write(value: Self) {
+        unsafe {
+            <Self as SysRegWrite>::write_raw(value.0);
+        }
+    }
+}

cortex-ar/src/register/dccisw.rs

@@ -0,0 +1,61 @@
+//! DCCISW (*Clean and Invalidate Data or Unified cache line by Set/Way.*)
+
+use arbitrary_int::u3;
+
+use crate::register::{SysReg, SysRegWrite};
+
+pub struct Dccisw(pub u32);
+
+impl Dccisw {
+    /// Create DCCISW value for cache cleaning and invalidation by set and way.
+    ///
+    /// ## Generics
+    ///
+    /// - A: log2(ASSOCIATIVITY) rounded up to the next integer if necessary. For example, a 4-way
+    ///   associative cache will have a value of 2 and a 8-way associative cache will have a value of
+    ///   3.
+    /// - N: log2(LINE LENGTH). For example, a 32-byte line length (4 words) will have a value of
+    ///   5.
+    #[inline]
+    pub const fn new<const A: usize, const N: usize>(way: u8, set: u16, level: u3) -> Self {
+        Self(super::dc_sw_ops::new::<A, N>(way, set, level))
+    }
+
+    /// Create DCCISW value for cache cleaning and invalidation by set and way.
+    /// Returns [None] on invalid input.
+    ///
+    /// # Arguments
+    ///
+    /// - a: log2(ASSOCIATIVITY) rounded up to the next integer if necessary. For example, a 4-way
+    ///   associative cache will have a value of 2 and a 8-way associative cache will have a value of
+    ///   3.
+    /// - n: log2(LINE LENGTH). For example, a 32-byte line length (4 words) will have a value of
+    ///   5.
+    #[inline]
+    pub const fn new_with_offsets(a: usize, way: u8, n: usize, set: u16, level: u3) -> Self {
+        Self(super::dc_sw_ops::new_with_offsets(a, way, n, set, level))
+    }
+}
+impl SysReg for Dccisw {
+    const CP: u32 = 15;
+    const CRN: u32 = 7;
+    const OP1: u32 = 0;
+    const CRM: u32 = 14;
+    const OP2: u32 = 2;
+}
+
+impl crate::register::SysRegWrite for Dccisw {}
+
+impl Dccisw {
+    #[inline]
+    /// Writes DCCISW (*Clean and Invalidate data or unified cache line by set/way.*)
+    ///
+    /// # Safety
+    ///
+    /// Ensure that this value is appropriate for this register
+    pub unsafe fn write(value: Self) {
+        unsafe {
+            <Self as SysRegWrite>::write_raw(value.0);
+        }
+    }
+}