AXI Bridge for PCI Express v2.4
37
PG055 June 4, 2014
Chapter 2:
Product Specification
Root Port Interrupt FIFO Read Register 2 (Offset 0x15C)
Reads from this location return queued interrupt messages. Data from each read follows the
format shown in
. For MSI interrupts, the message payload is presented in this
register, while the header information is presented in the Root Port Interrupt FIFO Read 1
register. The interrupt-handling flow should be to read the Root Port Interrupt FIFO Read 1
register first, immediately followed by this register. For non-Root Port cores, reads return 0.
For INTx interrupts, reads return zero.
Note:
Reads are non-destructive. Removing the message from the FIFO requires a write to either
this register or the Root Port Interrupt FIFO Read 1 register (write value is ignored).
VSEC Capability Register 2 (Offset 0x200)
The VSEC capability register (described in
) allows the memory space for the core
to appear as though it is a part of the underlying integrated block PCIe configuration space.
The VSEC is inserted immediately following the last enhanced capability structure in the
underlying block. VSEC is defined in §7.18 of the
PCI Express Base Specification, v1.1
(§7.19
.
This register is only included if C_INCLUDE_BAR_OFFSET_REG = 1.
VSEC Header Register 2 (Offset 0x204)
The VSEC Header Register 2 (described in
) provides a unique (within a given
vendor) identifier for the layout and contents of the VSEC structure, as well as its revision
and length.
This register is only included if C_INCLUDE_BAR_OFFSET_REG = 1.
Table 2-21:
Root Port Interrupt FIFO Read Register 2
Bits
Name
Core
Access
Reset
Value
Description
15:0
Message Data
RWC
0
Payload for MSI messages.
31:16 Reserved
RO
0
Reserved
Table 2-22:
VSEC Capability Register 2
Bits
Name
Core
Access
Reset
Value
Description
15:0
VSEC Capability ID
RO
0x000B PCI-SIG defined ID identifying this Enhanced Capability as a
Vendor-Specific capability. Hardcoded to 0x000B.
19:16 Capability Version
RO
0x1
Version of this capability structure. Hardcoded to 0x1.
31:20 Next Capability
Offset
RO
0x000
Offset to next capability.