zynq-rs/src/zynq/flash/transfer.rs

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2019-12-16 02:28:55 +08:00
use crate::regs::{RegisterR, RegisterW, RegisterRW};
use super::regs;
use super::{SpiWord, Flash, Manual};
pub struct Transfer<'a, Args: Iterator<Item = W>, W: Into<SpiWord>> {
flash: &'a mut Flash<Manual>,
args: Args,
sent: usize,
received: usize,
len: usize,
}
impl<'a, Args: Iterator<Item = W>, W: Into<SpiWord>> Transfer<'a, Args, W> {
pub fn new(flash: &'a mut Flash<Manual>, args: Args, len: usize) -> Self {
flash.regs.config.modify(|_, w| w.pcs(false));
flash.regs.enable.write(
regs::Enable::zeroed()
.spi_en(true)
);
let mut xfer = Transfer {
flash,
args,
sent: 0,
received: 0,
len,
};
xfer.fill_tx_fifo();
xfer.flash.regs.config.modify(|_, w| w.man_start_com(true));
xfer
}
fn fill_tx_fifo(&mut self) {
while self.sent < self.len && !self.flash.regs.intr_status.read().tx_fifo_full() {
let arg = self.args.next()
.map(|n| n.into())
.unwrap_or(SpiWord::W32(0));
match arg {
SpiWord::W32(w) => {
// println!("txd0 {:08X}", w);
unsafe {
self.flash.regs.txd0.write(w);
}
self.sent += 4;
}
// Only txd0 can be used without flushing
_ => {
if !self.flash.regs.intr_status.read().tx_fifo_not_full() {
// Flush if necessary
self.flash.regs.config.modify(|_, w| w.man_start_com(true));
self.flash.wait_tx_fifo_flush();
}
match arg {
SpiWord::W8(w) => {
// println!("txd1 {:02X}", w);
unsafe {
self.flash.regs.txd1.write(u32::from(w) << 24);
}
self.sent += 1;
}
SpiWord::W16(w) => {
unsafe {
self.flash.regs.txd2.write(u32::from(w) << 16);
}
self.sent += 2;
}
SpiWord::W24(w) => {
unsafe {
self.flash.regs.txd3.write(w << 8);
}
self.sent += 3;
}
SpiWord::W32(_) => unreachable!(),
}
self.flash.regs.config.modify(|_, w| w.man_start_com(true));
self.flash.wait_tx_fifo_flush();
}
}
}
}
fn can_read(&mut self) -> bool {
self.flash.regs.intr_status.read().rx_fifo_not_empty()
}
fn read(&mut self) -> u32 {
let rx = self.flash.regs.rx_data.read();
self.received += 4;
rx
}
}
impl<'a, Args: Iterator<Item = W>, W: Into<SpiWord>> Drop for Transfer<'a, Args, W> {
fn drop(&mut self) {
// Discard remaining rx_data
while self.can_read() {
self.read();
}
// Stop
self.flash.regs.enable.write(
regs::Enable::zeroed()
.spi_en(false)
);
self.flash.regs.config.modify(|_, w| w
.pcs(true)
.man_start_com(false)
);
}
}
impl<'a, Args: Iterator<Item = W>, W: Into<SpiWord>> Iterator for Transfer<'a, Args, W> {
type Item = u32;
fn next<'s>(&'s mut self) -> Option<u32> {
if self.received >= self.len {
return None;
}
self.fill_tx_fifo();
while !self.can_read() {}
Some(self.read())
}
}