Altera Arria V Hard IP for PCI Express - Manual (Page 236)

17–14 Chapter 17: Testbench and Design Example
Test Driver Module
Arria V Hard IP for PCI Express December 2013 Altera Corporation
User Guide
Each descriptor provides the hardware information on one DMA transfer. Table 17–10
describes each descriptor field.
Test Driver Module
The BFM driver module, altpcietb_bfm_driver_chaining.v is configured to test the
chaining DMA example Endpoint design. The BFM driver module configures the
Endpoint Configuration Space registers and then tests the example Endpoint chaining
DMA channel. This file is stored in the
<working_dir>testbench/<variation_name>/simulation/submodules directory.
The BFM test driver module performs the following steps in sequence:
1. Configures the Root Port and Endpoint Configuration Spaces, which the BFM test
driver module does by calling the procedure ebfm_cfg_rp_ep , which is part of
altpcietb_bfm_configure .
2. Finds a suitable BAR to access the example Endpoint design Control Register
space. Either BARs 2 or 3 must be at least a 256-byte memory BAR to perform the
DMA channel test. The
find_mem_bar procedure in the
altpcietb_bfm_driver_chaining does this.
Table 17–10. Chaining DMA Descriptor Fields
Descriptor Field
Endpoint
Access
RC Access Description
Endpoint Address R R/W
A 32-bit field that specifies the base address of the memory transfer on the
Endpoint site.
RC Address
Upper DWORD
R R/W Specifies the upper base address of the memory transfer on the RC site.
RC Address
Lower DWORD
R R/W Specifies the lower base address of the memory transfer on the RC site.
DMA Length R R/W Specifies the number of DMA DWORDs to transfer.
EPLAST_ENA R R/W
This bit is OR ’d with the EPLAST_ENA bit of the control register. When
EPLAST_ENA is set, the Endpoint DMA module updates the EPLAST field of
the descriptor table with the number of the last completed descriptor, in the
form <0 – n>. (Refer to
Table 17–7 .)
MSI_ENA R R/W
This bit is OR ’d with the MSI bit of the descriptor header. When this bit is set
the Endpoint DMA module sends an interrupt when the descriptor is
completed.