Chapter 7: Register Descriptions
7–21
PCI Express Avalon-MM Bridge Control Register Access Content
November 2012
Altera Corporation
Arria V GZ Hard IP for PCI Express
describes the Interrupt Status register when you configure the core as an
Endpoint. It records the status of all conditions that can cause an Avalon-MM
interrupt to be asserted. Refer to
Table 7–33
for the definition of the Interrupt Status
register when you configure the core as a Root Port.
An Avalon-MM interrupt can be asserted for any of the conditions noted in the
Avalon-MM Interrupt Status
register by setting the corresponding bits in the PCI
Express to Avalon-MM Interrupt Enable
register (
Table 7–36
).
PCI Express interrupts can also be enabled for all of the error conditions described.
However, it is likely that only one of the Avalon-MM or PCI Express interrupts can be
enabled for any given bit because typically a single process in either the PCI Express
or Avalon-MM domain is responsible for handling the condition reported by the
interrupt.
Avalon-MM Mailbox Registers
A processor local to the interconnect fabric typically requires write access to a set of
Avalon-MM-to-PCI Express Mailbox
registers and read-only access to a set of
PCI
Express-to-Avalon-MM Mailbox
registers. Eight mailbox registers are available.
Table 7–35. PCI Express to Avalon-MM Interrupt Status Register for Endpoints
0x3060
Bits
Name
Access Description
0
ERR_PCI_WRITE_
FAILURE
RW1C
When set to 1, indicates a PCI Express write failure. This bit can
also be cleared by writing a 1 to the same bit in the
Avalon-MM to
PCI Express Interrupt Status
register.
1
ERR_PCI_READ_
FAILURE
RW1C
When set to 1, indicates the failure of a PCI Express read. This bit
can also be cleared by writing a 1 to the same bit in the
Avalon-MM
to PCI Express Interrupt Status
register.
[15:2]
Reserved
—
—
[16]
P2A_MAILBOX_INT0
RW1C
1 when the P2A_MAILBOX0 is written
[17]
P2A_MAILBOX_INT1
RW1C
1 when the P2A_MAILBOX1 is written
[18]
P2A_MAILBOX_INT2
RW1C
1 when the P2A_MAILBOX2 is written
[19]
P2A_MAILBOX_INT3
RW1C
1 when the P2A_MAILBOX3 is written
[20]
P2A_MAILBOX_INT4
RW1C
1 when the P2A_MAILBOX4 is written
[21]
P2A_MAILBOX_INT5
RW1C
1 when the P2A_MAILBOX5 is written
[22]
P2A_MAILBOX_INT6
RW1C
1 when the P2A_MAILBOX6 is written
[23]
P2A_MAILBOX_INT7
RW1C
1 when the P2A_MAILBOX7 is written
[31:24]
Reserved
—
—
Table 7–36. INT-X Interrupt Enable Register for Endpoints
0x3070
Bits
Name
Access Description
[31:0]
PCI Express to
Avalon-MM
Interrupt Enable
RW
When set to 1, enables the interrupt for the corresponding bit in
the
PCI Express to Avalon-MM Interrupt Status
register
to cause the Avalon Interrupt signal (
cra_Irq_o
) to be asserted.
Only bits implemented in the
PCI Express to Avalon-MM
Interrupt Status
register are implemented in the Enable
register. Reserved bits cannot be set to a 1.