vesper/src/platform/uart.rs

241 lines
7.0 KiB
Rust

use arch::*;
use core::{fmt, ops};
use platform::{gpio, rpi3::PERIPHERAL_BASE};
use register::mmio::*;
// The base address for UART.
const UART0_BASE: u32 = PERIPHERAL_BASE + 0x20_1000;
// The offsets for reach register for the UART.
const UART0_DR: u32 = UART0_BASE + 0x00;
const UART0_RSRECR: u32 = UART0_BASE + 0x04;
const UART0_FR: u32 = UART0_BASE + 0x18;
const UART0_ILPR: u32 = UART0_BASE + 0x20;
const UART0_IBRD: u32 = UART0_BASE + 0x24;
const UART0_FBRD: u32 = UART0_BASE + 0x28;
const UART0_LCRH: u32 = UART0_BASE + 0x2C;
const UART0_CR: u32 = UART0_BASE + 0x30;
const UART0_IFLS: u32 = UART0_BASE + 0x34;
const UART0_IMSC: u32 = UART0_BASE + 0x38;
const UART0_RIS: u32 = UART0_BASE + 0x3C;
const UART0_MIS: u32 = UART0_BASE + 0x40;
const UART0_ICR: u32 = UART0_BASE + 0x44;
const UART0_DMACR: u32 = UART0_BASE + 0x48;
const UART0_ITCR: u32 = UART0_BASE + 0x80;
const UART0_ITIP: u32 = UART0_BASE + 0x84;
const UART0_ITOP: u32 = UART0_BASE + 0x88;
const UART0_TDR: u32 = UART0_BASE + 0x8C;
// Mini UART
const UART1_BASE: u32 = PERIPHERAL_BASE + 0x21_5000;
#[allow(non_snake_case)]
#[repr(C)]
pub struct RegisterBlock {
__reserved_0: u32, // 0x00 - AUX_IRQ
AUX_ENABLES: ReadWrite<u32, AUX_ENABLES::Register>, // 0x04
__reserved_1: [u32; 14], // 0x08
AUX_MU_IO: ReadWrite<u32>, // 0x40 - Mini Uart I/O Data
AUX_MU_IER: WriteOnly<u32>, // 0x44 - Mini Uart Interrupt Enable
AUX_MU_IIR: WriteOnly<u32, AUX_MU_IIR::Register>, // 0x48
AUX_MU_LCR: WriteOnly<u32, AUX_MU_LCR::Register>, // 0x4C
AUX_MU_MCR: WriteOnly<u32>, // 0x50
AUX_MU_LSR: ReadOnly<u32, AUX_MU_LSR::Register>, // 0x54
__reserved_2: [u32; 2], // 0x58 - AUX_MU_MSR, AUX_MU_SCRATCH
AUX_MU_CNTL: WriteOnly<u32, AUX_MU_CNTL::Register>, // 0x60
__reserved_3: u32, // 0x64 - AUX_MU_STAT
AUX_MU_BAUD: WriteOnly<u32, AUX_MU_BAUD::Register>, // 0x68
}
// Auxiliary mini UART registers
//
// Descriptions taken from
// https://github.com/raspberrypi/documentation/files/1888662/BCM2837-ARM-Peripherals.-.Revised.-.V2-1.pdf
register_bitfields! {
u32,
/// Auxiliary enables
AUX_ENABLES [
/// If set the mini UART is enabled. The UART will immediately
/// start receiving data, especially if the UART1_RX line is
/// low.
/// If clear the mini UART is disabled. That also disables any
/// mini UART register access
MINI_UART_ENABLE OFFSET(0) NUMBITS(1) []
],
/// Mini Uart Interrupt Identify
AUX_MU_IIR [
/// Writing with bit 1 set will clear the receive FIFO
/// Writing with bit 2 set will clear the transmit FIFO
FIFO_CLEAR OFFSET(1) NUMBITS(2) [
Rx = 0b01,
Tx = 0b10,
All = 0b11
]
],
/// Mini Uart Line Control
AUX_MU_LCR [
/// Mode the UART works in
DATA_SIZE OFFSET(0) NUMBITS(2) [
SevenBit = 0b00,
EightBit = 0b11
]
],
/// Mini Uart Line Status
AUX_MU_LSR [
/// This bit is set if the transmit FIFO can accept at least
/// one byte.
TX_EMPTY OFFSET(5) NUMBITS(1) [],
/// This bit is set if the receive FIFO holds at least 1
/// symbol.
DATA_READY OFFSET(0) NUMBITS(1) []
],
/// Mini Uart Extra Control
AUX_MU_CNTL [
/// If this bit is set the mini UART transmitter is enabled.
/// If this bit is clear the mini UART transmitter is disabled.
TX_EN OFFSET(1) NUMBITS(1) [
Disabled = 0,
Enabled = 1
],
/// If this bit is set the mini UART receiver is enabled.
/// If this bit is clear the mini UART receiver is disabled.
RX_EN OFFSET(0) NUMBITS(1) [
Disabled = 0,
Enabled = 1
]
],
/// Mini Uart Baudrate
AUX_MU_BAUD [
/// Mini UART baudrate counter
RATE OFFSET(0) NUMBITS(16) []
]
}
pub struct MiniUart;
/// Deref to RegisterBlock
///
/// Allows writing
/// ```
/// self.MU_IER.read()
/// ```
/// instead of something along the lines of
/// ```
/// unsafe { (*MiniUart::ptr()).MU_IER.read() }
/// ```
impl ops::Deref for MiniUart {
type Target = RegisterBlock;
fn deref(&self) -> &Self::Target {
unsafe { &*Self::ptr() }
}
}
impl MiniUart {
pub fn new() -> MiniUart {
MiniUart
}
/// Returns a pointer to the register block
fn ptr() -> *const RegisterBlock {
UART1_BASE as *const _
}
///Set baud rate and characteristics (115200 8N1) and map to GPIO
#[cfg(not(feature = "noserial"))]
pub fn init(&self) {
// initialize UART
self.AUX_ENABLES.modify(AUX_ENABLES::MINI_UART_ENABLE::SET);
self.AUX_MU_IER.set(0);
self.AUX_MU_CNTL.set(0);
self.AUX_MU_LCR.write(AUX_MU_LCR::DATA_SIZE::EightBit);
self.AUX_MU_MCR.set(0);
self.AUX_MU_IER.set(0);
self.AUX_MU_IIR.write(AUX_MU_IIR::FIFO_CLEAR::All);
self.AUX_MU_BAUD.write(AUX_MU_BAUD::RATE.val(270)); // 115200 baud
// map UART1 to GPIO pins
unsafe {
(*gpio::GPFSEL1).modify(gpio::GPFSEL1::FSEL14::TXD1 + gpio::GPFSEL1::FSEL15::RXD1);
(*gpio::GPPUD).set(0); // enable pins 14 and 15
loop_delay(150);
(*gpio::GPPUDCLK0).write(
gpio::GPPUDCLK0::PUDCLK14::AssertClock + gpio::GPPUDCLK0::PUDCLK15::AssertClock,
);
loop_delay(150);
(*gpio::GPPUDCLK0).set(0);
}
self.AUX_MU_CNTL
.write(AUX_MU_CNTL::RX_EN::Enabled + AUX_MU_CNTL::TX_EN::Enabled);
}
#[cfg(feature = "noserial")]
pub fn init(&self) {}
/// Send a character
#[cfg(not(feature = "noserial"))]
pub fn send(&self, c: char) {
// wait until we can send
loop_until(|| self.AUX_MU_LSR.is_set(AUX_MU_LSR::TX_EMPTY));
// write the character to the buffer
self.AUX_MU_IO.set(c as u32);
}
#[cfg(feature = "noserial")]
pub fn send(&self, _c: char) {}
/// Receive a character
#[cfg(not(feature = "noserial"))]
pub fn getc(&self) -> char {
// wait until something is in the buffer
loop_until(|| self.AUX_MU_LSR.is_set(AUX_MU_LSR::DATA_READY));
// read it and return
let ret = self.AUX_MU_IO.get() as u8 as char;
// convert carriage return to newline
if ret == '\r' {
'\n'
} else {
ret
}
}
#[cfg(feature = "noserial")]
pub fn getc(&self) -> char {
'\n'
}
/// Display a string
pub fn puts(&self, string: &str) {
for c in string.chars() {
// convert newline to carriage return + newline
if c == '\n' {
self.send('\r')
}
self.send(c);
}
}
}
impl fmt::Write for MiniUart {
fn write_str(&mut self, s: &str) -> fmt::Result {
self.puts(s);
Ok(())
}
}