Altera IP Compiler for PCI Express - Manual (Page 244)

15–12 Chapter 15: Testbench and Design Example
Chaining DMA Design Example
IP Compiler for PCI Express User Guide August 2014 Altera Corporation
as well as other miscellaneous status registers.
■ altpcierd_dma_dt —This module arbitrates PCI Express packets issued by the
submodules altpcierd_dma_prg_reg, altpcierd_read_dma_requester,
altpcierd_write_dma_requester
and altpcierd_dma_descriptor.
■ altpcierd_dma_prg_reg —This module contains the chaining DMA control
registers which get programmed by the software application or BFM driver.
■ altpcierd_dma_descriptor —This module retrieves the DMA read or write
descriptor from the BFM shared memory, and stores it in a descriptor FIFO.
This module issues upstream PCI Express TLPs of type Mrd.
■ altpcierd_read_dma_requester , altpcierd_read_dma_requester_128—For each
descriptor located in the altpcierd_descriptor FIFO, this module transfers data
from the BFM shared memory to the endpoint memory by issuing MRd PCI
Express transaction layer packets. altpcierd_read_dma_requester is used with
the 64-bit Avalon-ST IP core. altpcierd_read_dma_requester_128 is used with
the 128-bit Avalon-ST IP core.
■ altpcierd_write_dma_requester, altpcierd_write_dma_requester_128 —For
each descriptor located in the altpcierd_descriptor FIFO, this module transfers
data from the endpoint memory to the BFM shared memory by issuing MWr
PCI Express transaction layer packets. altpcierd_write_dma_requester is used
with the 64-bit Avalon-ST IP core. altpcierd_write_dma_requester_128 is used
with the 128-bit Avalon-ST IP core.
■ altpcierd_cpld_rx_buffer —This modules monitors the available space of the
RX Buffer; It prevents RX Buffer overflow by arbitrating memory read request
issued by the application.
■ altpcierd_cdma_ecrc_check_64 , altpcierd_cdma_ecrc_check_128—This
module checks for and flags PCI Express ECRC errors on TLPs as they are
received on the Avalon-ST interface of the chaining DMA.
altpcierd_cdma_ecrc_check_64
is used with the 64-bit Avalon-ST IP core.
altpcierd_cdma_ecrc_check_128 is used with the 128-bit Avalon-ST IP core.
■ altpcierd_cdma_rx_ecrc_64.v , altpcierd_cdma_rx_ecrc_64_altcrc.v,
altpcierd_cdma_rx_ecrc_64.vo —These modules contain the CRC32 checking
Megafunction used in the altpcierd_ecrc_check_64 module. The .v files are
used for synthesis. The .vo file is used for simulation.
■ altpcierd_cdma_ecrc_gen —This module generates PCI Express ECRC and
appends it to the end of the TLPs transmitted on the Avalon-ST TX interface of
the chaining DMA. This module instantiates the altpcierd_cdma_gen_ctl_64,
altpcierd_cdma_gen_ctl_128
, and altpcierd_cdma_gen_datapath modules.
■ altpcierd_cdma_ecrc_gen_ctl_64 , altpcierd_cdma_ecrc_gen_ctl_128—This
module controls the data stream going to the altpcierd_cdma_tx_ecrc module
for ECRC calculation, and generates controls for the main datapath
(altpcierd_cdma_ecrc_gen_datapath).
■ altpcierd_cdma_ecrc gen_datapath—This module routes the Avalon-ST data
through a delay pipe before sending it across the Avalon-ST interface to the IP
core to ensure the ECRC is available when the end of the TLP is transmitted
across the Avalon-ST interface.
■ altpcierd_cdma_ecrc_gen_calc —This module instantiates the TX ECRC core.