Struct AdvancedTxDescriptor 

#[repr(C)]
pub struct AdvancedTxDescriptor {
    pub packet_buffer_address: Volatile<u64>,
    pub data_len: Volatile<u16>,
    pub dtyp_mac_rsv: Volatile<u8>,
    pub dcmd: Volatile<u8>,
    pub paylen_popts_cc_idx_sta: Volatile<u32>,
}

Advanced Transmit Descriptor used by the ixgbe NIC driver.

Two usage modes

It has 2 modes: Read and Write Back, both of which use the whole 128 bits. There is one transmit descriptor per transmit buffer; it can be converted between these 2 modes.

Read contains the addresses that the driver writes. Write Back contains information the hardware writes on receiving a packet.

More information can be found in the 82599 datasheet.

Fields

packet_buffer_address: Volatile<u64>

Starting physical address of the receive buffer for the packet.

data_len: Volatile<u16>

Length of data buffer

dtyp_mac_rsv: Volatile<u8>

A multi-part field:

• dtyp: Descriptor Type, occupies bits [7:4],
• mac: options to apply LinkSec and time stamp, occupies bits [3:2].

dcmd: Volatile<u8>

Command bits

paylen_popts_cc_idx_sta: Volatile<u32>

A multi-part field:

• paylen: the size in bytes of the data buffer in host memory. not including the fields that the hardware adds), occupies bits [31:14].
• popts: options to offload checksum calculation, occupies bits [13:8].
• sta: status of the descriptor (whether it’s in use or not), occupies bits [3:0].

Implementations

impl AdvancedTxDescriptor

pub fn init(&mut self)

Initializes a transmit descriptor by clearing all of its values.

pub fn send(&mut self, transmit_buffer_addr: u64, transmit_buffer_length: u16)

Updates the transmit descriptor to send the packet. We assume that one transmit descriptor will be used to send one packet.

Arguments

• transmit_buffer_addr: physical address of the transmit buffer.
• transmit_buffer_length: length of packet we want to send.

pub fn wait_for_packet_tx(&self)

Polls the Descriptor Done bit until the packet has been sent.