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UART FIFO-buffered driver and Rust bindings
Allows wrapping the raw UART API with software RX and TX FIFOs that can be accessed from user space. Interrupt handlers move data between the hardware fifos and memory. This way, interrupt handlers do not need to be specifically written to deal with application-specific UART use cases from kernel mode. Signals are provided for a thread to be woken on read or write readiness. Behaves similarly to a UNIX file, supporting blocking and non-blocking reads and writes. Update serial example to use this and remove bindings for uart_pipe.
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‎.clang-format‎

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# SPDX-License-Identifier: GPL-2.0
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#
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# clang-format configuration file. Intended for clang-format >= 4.
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#
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# For more information, see:
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#
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# Documentation/process/clang-format.rst
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# https://clang.llvm.org/docs/ClangFormat.html
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# https://clang.llvm.org/docs/ClangFormatStyleOptions.html
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#
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---
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AccessModifierOffset: -4
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#AlignEscapedNewlines: Left # Unknown to clang-format-4.0
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# Taken from:
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# git grep -h '^#define [^[:space:]]*for_each[^[:space:]]*(' include/ \
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# | sed "s,^#define \([^[:space:]]*for_each[^[:space:]]*\)(.*$, - '\1'," \
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# | sort | uniq
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- 'FOR_EACH'
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- 'for_each_linux_bus'
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- 'for_each_linux_driver'
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- 'metal_bitmap_for_each_clear_bit'
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- 'SYS_SLIST_FOR_EACH_NODE'
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- 'SYS_SLIST_FOR_EACH_NODE_SAFE'
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- '_WAIT_Q_FOR_EACH'
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- 'Z_GENLIST_FOR_EACH_CONTAINER'
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- 'Z_GENLIST_FOR_EACH_CONTAINER_SAFE'
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- 'Z_GENLIST_FOR_EACH_NODE'
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- 'Z_GENLIST_FOR_EACH_NODE_SAFE'
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IncludeCategories:
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- Regex: '.*'
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ObjCSpaceAfterProperty: true
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#PenaltyBreakAssignment: 10 # Unknown to clang-format-4.0
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‎CMakeLists.txt‎

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cmake_minimum_required(VERSION 3.13.1)
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add_subdirectory(uart-buffered)
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# Use a clang_target known to clang so headers will be processed correctly with
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# bindgen. rust_target may point to a custom json target.
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if(${ARCH} STREQUAL "posix" OR ${ARCH} STREQUAL "x86")

‎Kconfig‎

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of the entire pool.
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endif
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endif
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config UART_BUFFERED
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bool "UART fifo buffered driver"
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depends on SERIAL && UART_INTERRUPT_DRIVEN
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select POLL
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help
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Allows wrapping the raw UART API with software RX and TX FIFOs that
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can be accessed from user space. Interrupt handlers move data between
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the hardware fifos and memory. This way, interrupt handlers do not
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need to be specifically written to deal with application-specific
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UART use cases from kernel mode. Signals are provided for a thread to
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be woken on read or write readiness. Behaves similarly to a UNIX
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file, supporting blocking and non-blocking reads and writes.

‎rust/sysroot-stage2/Cargo.lock‎

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Some generated files are not rendered by default. Learn more about customizing how changed files appear on GitHub.

‎rust/sysroot-stage2/Cargo.toml‎

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[dependencies.zephyr-logger]
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path = "../zephyr-logger"
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[dependencies.zephyr-uart-buffered]
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path = "../zephyr-uart-buffered"
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[profile.release]
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lto = true
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panic = "abort"

‎rust/zephyr-sys/wrapper.h‎

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#include <misc/mempool.h>
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#include <device.h>
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#include <uart.h>
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#include <drivers/console/uart_pipe.h>
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#include <uart_buffered.h>
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// Create a constant we can use from Rust in all cases
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#ifdef CONFIG_USERSPACE

‎rust/zephyr-uart-buffered/Cargo.toml‎

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[package]
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name = "zephyr-uart-buffered"
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version = "0.1.0"
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authors = ["Tyler Hall <tylerwhall@gmail.com>"]
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edition = "2018"
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[dependencies]

‎rust/zephyr-uart-buffered/src/lib.rs‎

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extern crate zephyr_core;
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extern crate zephyr_sys;
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use zephyr_core::poll::KPollSignal;
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use zephyr_core::NegErr;
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use zephyr_sys::raw::{uart_buffered_rx_handle, uart_buffered_tx_handle};
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pub struct UartBufferedRx {
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handle: uart_buffered_rx_handle,
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}
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impl UartBufferedRx {
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pub unsafe fn new(handle: uart_buffered_rx_handle) -> Self {
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UartBufferedRx { handle }
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}
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/// Infallible read (lower level than `std::io::Read`)
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pub fn read(&mut self, buf: &mut [u8]) -> usize {
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unsafe {
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zephyr_sys::raw::uart_buffered_read(
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&self.handle as *const _ as *mut _,
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buf.as_mut_ptr(),
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buf.len(),
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)
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}
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}
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/// Non blocking read. Returns None if nothing read, else returns number of bytes read.
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pub fn read_nb(&mut self, buf: &mut [u8]) -> Option<usize> {
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unsafe {
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zephyr_sys::raw::uart_buffered_read_nb(
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&self.handle as *const _ as *mut _,
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buf.as_mut_ptr(),
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buf.len(),
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)
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}
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.neg_err()
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.ok()
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.map(|len| len as usize)
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}
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/// Get reference to signal to wait on for non-blocking readiness. Static
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/// lifetime because uart buffered can only be declared statically.
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pub fn get_signal(&self) -> &'static KPollSignal {
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unsafe { &*self.handle.fifo.signal }
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}
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}
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pub struct UartBufferedTx {
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handle: uart_buffered_tx_handle,
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}
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impl UartBufferedTx {
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pub unsafe fn new(handle: uart_buffered_tx_handle) -> Self {
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UartBufferedTx { handle }
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}
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/// Infallible write (lower level than `std::io::Write`)
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pub fn write(&mut self, buf: &[u8]) {
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unsafe {
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zephyr_sys::raw::uart_buffered_write(
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&self.handle as *const _ as *mut _,
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buf.as_ptr(),
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buf.len(),
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)
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}
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}
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/// Non blocking write. Returns None if nothing written, else returns number of bytes written.
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pub fn write_nb(&mut self, buf: &[u8]) -> Option<usize> {
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unsafe {
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zephyr_sys::raw::uart_buffered_write_nb(
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&self.handle as *const _ as *mut _,
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buf.as_ptr(),
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buf.len(),
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)
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}
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.neg_err()
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.ok()
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.map(|len| len as usize)
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}
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/// Get reference to signal to wait on for non-blocking readiness. Static
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/// lifetime because uart buffered can only be declared statically.
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pub fn get_signal(&self) -> &'static KPollSignal {
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unsafe { &*self.handle.fifo.signal }
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}
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}

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