| // SPDX-License-Identifier: Apache-2.0 OR MIT |
| // |
| // Copyright (c) 2018-2022 by the author(s) |
| // |
| // Author(s): |
| // - Andre Richter <andre.o.richter@gmail.com> |
| |
| //! Low level access to Cortex-A processors. |
| //! |
| //! ## Currently Supported Execution States |
| //! |
| //! - [x] AArch64 |
| //! - [ ] AArch32 |
| //! |
| //! ## Minimum Supported Rust Version |
| //! |
| //! Requires a recent nightly of Rust. |
| //! |
| //! ## Usage |
| //! |
| //! Please note that for using this crate's [register definitions](src/registers) (as provided by |
| //! `cortex_a::registers::*`), you need to also include |
| //! [`tock-registers`](https://crates.io/crates/tock-registers) in your project. This is because the |
| //! `interface` traits provided by `tock-registers` are implemented by this crate. You should |
| //! include the same version of `tock-registers` as is being used by this crate to ensure sane |
| //! interoperatbility. |
| //! |
| //! For example, in the following snippet, `X.Y.Z` should be the same version of `tock-registers` |
| //! that is mentioned in `cortex-a`'s [`Cargo.toml`](Cargo.toml). |
| //! |
| //! ```toml |
| //! [package] |
| //! name = "Your embedded project" |
| //! |
| //! # Some parts omitted for brevity. |
| //! |
| //! [dependencies] |
| //! tock-registers = "X.Y.Z" |
| //! cortex-a = "A.B.C" # <-- Includes tock-registers itself. |
| //! ``` |
| //! |
| //! ### Example |
| //! |
| //! Check out https://github.com/rust-embedded/rust-raspberrypi-OS-tutorials for usage examples. |
| //! Listed below is a snippet of `rust-raspberrypi-OS-tutorials`'s early boot code. |
| //! |
| //! ```rust |
| //! use cortex_a::{asm, registers::*}; |
| //! use tock_registers::interfaces::Writeable; // <-- Trait needed to use `write()` and `set()`. |
| //! |
| //! // Some parts omitted for brevity. |
| //! |
| //! unsafe fn prepare_el2_to_el1_transition( |
| //! virt_boot_core_stack_end_exclusive_addr: u64, |
| //! virt_kernel_init_addr: u64, |
| //! ) { |
| //! // Enable timer counter registers for EL1. |
| //! CNTHCTL_EL2.write(CNTHCTL_EL2::EL1PCEN::SET + CNTHCTL_EL2::EL1PCTEN::SET); |
| //! |
| //! // No offset for reading the counters. |
| //! CNTVOFF_EL2.set(0); |
| //! |
| //! // Set EL1 execution state to AArch64. |
| //! HCR_EL2.write(HCR_EL2::RW::EL1IsAarch64); |
| //! |
| //! // Set up a simulated exception return. |
| //! SPSR_EL2.write( |
| //! SPSR_EL2::D::Masked |
| //! + SPSR_EL2::A::Masked |
| //! + SPSR_EL2::I::Masked |
| //! + SPSR_EL2::F::Masked |
| //! + SPSR_EL2::M::EL1h, |
| //! ); |
| //! ``` |
| //! |
| //! ## Disclaimer |
| //! |
| //! Descriptive comments in the source files are taken from the [ARM Architecture Reference Manual |
| //! ARMv8, for ARMv8-A architecture |
| //! profile](https://static.docs.arm.com/ddi0487/ca/DDI0487C_a_armv8_arm.pdf?_ga=2.266626254.1122218691.1534883460-1326731866.1530967873). |
| |
| #![feature(core_intrinsics)] |
| #![feature(custom_inner_attributes)] |
| #![no_std] |
| |
| pub mod asm; |
| pub mod registers; |