17–16 Chapter 17: Testbench and Design Example
Test Driver Module
Cyclone V Hard IP for PCI Express December 2013 Altera Corporation
User Guide
2. Sets up the chaining DMA descriptor header and starts the transfer data from the
Endpoint memory to the BFM shared memory. The transfer calls the procedure
dma_set_header
which writes four dwords, DW0:DW3 (Table 17–14), into the
DMA write register module.
After writing the last dword, DW3, of the descriptor header, the DMA write starts
the three subsequent data transfers.
3. Waits for the DMA write completion by polling the BFM share memory location
0x80c, where the DMA write engine is updating the value of the number of
completed descriptor. Calls the procedures
rcmem_poll
and
msi_poll
to determine
when the DMA write transfers have completed.
Table 17–12. Write Descriptor 1
Offset in BFM
Shared Memory
Value Description
DW0 0x820 1,024
Transfer length in dwords and control bits as described in on
page 17–14
DW1 0x824 0 Endpoint address
DW2 0x828 0 BFM shared memory data buffer 1 upper address value
DW3 0x82c 0x2800 BFM shared memory data buffer 1 lower address value
Data
Buffer 1
0x02800
Increment by 1 from
0x2525_0001
Data content in the BFM shared memory from address: 0x02800
Table 17–13. Write Descriptor 2
Offset in BFM
Shared Memory
Value Description
DW0 0x830 644
Transfer length in dwords and control bits as described in
Table 17–3 on page 17–10
DW1 0x834 0 Endpoint address
DW2 0x838 0 BFM shared memory data buffer 2 upper address value
DW3 0x83c 0x057A0 BFM shared memory data buffer 2 lower address value
Data
Buffer 2
0x057A0
Increment by 1 from
0x3535_0001
Data content in the BFM shared memory from address: 0x057A0
Table 17–14. DMA Control Register Setup for DMA Write
Offset in DMA
Control Register
(BAR2)
Value Description
DW0 0x0 3
Number of descriptors and control bits as described in Table 17–2 on
page 17–10
DW1 0x4 0 BFM shared memory descriptor table upper address value
DW2 0x8 0x800 BFM shared memory descriptor table lower address value
DW3 0xc 2 Last valid descriptor
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