Arm PrimeCell UART (PL011) driver

Driver implementation for the PL011 UART peripheral.

The driver is designed to function regardless of whether a Memory Management Unit (MMU) is present. The primary role of the OwnedMmioPointer is to manage the lifetime of the peripheral, ensuring proper resource handling. In a system that includes an MMU, the peripheral's lifetime is dynamic because it is mapped into memory rather than having a fixed address. In a system without an MMU, the OwnedMmioPointer can be instantiated directly from the physical address of the register block, providing access to the peripheral without requiring memory mapping.

Implemented features

• Enabling/disabling UART peripheral which includes configuring the data bit number, parity settings, stop bit count and baudrate
• Checking various status flags
• Non-blocking read/write functions
• Handling UART errors
• Reading UART identification structure
• 98% unit test coverage
• Implementing various traits
  • embedded_hal_nb::serial::{Write, Read}
  • embedded_io::{Write, Read}
  • core::fmt::Write

Future plans

• Implementing interrupt enablement
• Handling modem control and status signals
• Adding peripheral testing

License

The project is MIT and Apache-2.0 dual licensed, see LICENSE-APACHE and LICENSE-MIT.

Maintainers

arm-pl011-uart is a trustedfirmware.org maintained project. All contributions are ultimately merged by the maintainers listed below.

• Bálint Dobszay balint.dobszay@arm.com balint-dobszay-arm
• Imre Kis imre.kis@arm.com imre-kis-arm
• Sandrine Afsa sandrine.afsa@arm.com sandrine-bailleux-arm

Contributing

Please follow the directions of the Trusted Firmware Processes

Reporting Security Issues

Please follow the directions of the Trusted Firmware Security Center

Copyright 2024 Arm Limited and/or its affiliates open-source-office@arm.com