forked from M-Labs/zynq-rs
115 lines
3.2 KiB
Rust
115 lines
3.2 KiB
Rust
use core::ops::{Deref, DerefMut};
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use crate::{register, register_bit, register_bits, register_bits_typed, regs::*};
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use super::{MTU, regs};
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/// Descriptor entry
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pub struct DescEntry {
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word0: DescWord0,
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word1: DescWord1,
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}
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register!(desc_word0, DescWord0, RW, u32);
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register_bits!(desc_word0, address, u32, 0, 31);
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register!(desc_word1, DescWord1, RW, u32);
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register_bits!(desc_word1, length, u16, 0, 13);
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register_bit!(desc_word1, last_buffer, 15);
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register_bit!(desc_word1, no_crc_append, 16);
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register_bits!(desc_word1, csum_offload_errors, u8, 20, 22);
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register_bit!(desc_word1, late_collision_tx_error, 26);
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register_bit!(desc_word1, ahb_frame_corruption, 27);
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register_bit!(desc_word1, retry_limit_exceeded, 29);
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/// marks last descriptor in list
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register_bit!(desc_word1, wrap, 30);
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/// true if owned by software, false if owned by hardware
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register_bit!(desc_word1, used, 31);
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/// Number of descriptors
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pub const DESCS: usize = 8;
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#[repr(C)]
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pub struct DescList<'a> {
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list: &'a mut [DescEntry],
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buffers: &'a mut [[u8; MTU]],
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next: usize,
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}
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impl<'a> DescList<'a> {
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pub fn new(list: &'a mut [DescEntry], buffers: &'a mut [[u8; MTU]]) -> Self {
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let last = list.len().min(buffers.len()) - 1;
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for (i, (entry, buffer)) in list.iter_mut().zip(buffers.iter_mut()).enumerate() {
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let is_last = i == last;
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let buffer_addr = &mut buffer[0] as *mut _ as u32;
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assert!(buffer_addr & 0b11 == 0);
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entry.word0.write(
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DescWord0::zeroed()
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.address(buffer_addr)
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);
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entry.word1.write(
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DescWord1::zeroed()
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.used(true)
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.wrap(is_last)
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);
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}
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DescList {
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list,
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buffers,
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next: 0,
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}
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}
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pub fn list_addr(&self) -> u32 {
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&self.list[0] as *const _ as u32
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}
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pub fn send<'s: 'p, 'p>(&'s mut self, regs: &'p mut regs::RegisterBlock, length: usize) -> Option<PktRef<'p>> {
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let list_len = self.list.len();
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let entry = &mut self.list[self.next];
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if entry.word1.read().used() {
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entry.word1.modify(|_, w| w.length(length as u16));
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let buffer = &mut self.buffers[self.next][0..length];
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self.next += 1;
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if self.next >= list_len {
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self.next = 0;
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}
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Some(PktRef { entry, buffer, regs })
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} else {
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// Still in use by HW (sending too fast, ring exceeded)
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None
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}
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}
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}
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/// Releases a buffer back to the HW upon Drop, and start the TX
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/// engine
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pub struct PktRef<'a> {
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entry: &'a mut DescEntry,
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buffer: &'a mut [u8],
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regs: &'a mut regs::RegisterBlock,
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}
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impl<'a> Drop for PktRef<'a> {
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fn drop(&mut self) {
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self.entry.word1.modify(|_, w| w.used(false));
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self.regs.net_ctrl.modify(|_, w|
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w.tx_en(true)
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);
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}
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}
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impl<'a> Deref for PktRef<'a> {
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type Target = [u8];
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fn deref(&self) -> &Self::Target {
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self.buffer
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}
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}
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impl<'a> DerefMut for PktRef<'a> {
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fn deref_mut(&mut self) -> &mut <Self as Deref>::Target {
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self.buffer
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}
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}
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