Altera V-Series Avalon-MM DMA - Manual (Page 91)

Address
Offset
Register Name
Description
0x04 WR_RC_HIGH_SRC_ADDR Upper dword of the write DMA source address.
Specifies the address in the Avalon-MM domain from
which the Write DMA fetches data.
0x08 WR_CTLR_LOW_DEST_ADDR Lower dword of the write DMA destination address.
Specifies the address in Root Complex memory to which
the Write DMA writes data.
0x0C WR_CTRL_HIGH_DEST_ADDR Upper dword of the write DMA destination address.
Specifies the address in Root Complex memory to which
the Write DMA writes data.
0x10
CONTROL
Specifies the following information:
• [31:25]: Reserved must be 0.
• [24:18]:
ID
: Specifies the
Descriptor ID
.
Descriptor
ID
0 is at the beginning of the table.
Descriptor ID
is at the end of the table.
• [17:0] :
SIZE
: The transfer size in dwords. Must be
non-zero. The maximum transfer size in 1 MBytes -
4 bytes.
0x14 -
0x1C
Reserved N/A
Read DMA Example
The following example moves three data blocks from the PCIe address space to the Avalon-MM address
space. Host software running on an embedded CPU allocates the memory and programs creates the
descriptor table in PCIe address space. The following figures illustrate the location and size of the data
blocks in the PCIe and Avalon-MM address spaces and the descriptor table format. In this example, the
value of
RD_TABLE_SIZE
is 127.
Figure 5-10: Data Blocks to Transfer from PCIe to Avalon-MM Address Space Using Read DMA
256 KB
512 KB
1 MB
Addr 0x1_2000_0000
Addr 0x2000_0000
Addr 0x1000_0000
PCIe System Memory
1 MB
256 KB
512 KB
Addr 0x5000_0000
Addr 0x1000_0000
Addr 0x0001_0000
Avalon-MM Memory
5-22 Read DMA Example
UG-01154
2014.12.18
Altera Corporation Registers
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