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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Develepor’s Manual
Order Number: 306262-004US
569
PCI Controller—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
10.5.3.16 PCI Doorbell Register
10.5.3.17 AHB-to-PCI DMA AHB Address Register 0
Register Name:
pci_pcidoorbell
Block
Base Address:
0xC00000
Offset Address
0x3c
Reset Value
0x00000000
Register Description:
The Intel XScale processor writes this register to generate an
interrupt to an external PCI device on PCI_INTA_N. Any bit set to a
1 will generate the PCI interrupt if the PCI doorbell interrupt is
enabled (pci_inten.PDBEN = 1). This register is write-1-to-set from
AHB and write-1-to-clear from PCI. The Intel XScale processor
writes a 1 to a bit or pattern of bits to generate the interrupt. The
external PCI device reads the register and writes 1(s) to clear the
bit(s) and deassert the interrupt. If the DBT (Doorbell Test) bit is
set in the pci_csr register, all bits become read/write from the AHB
bus.
Access:
(See below.)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
PDB
Register
pci_pcidoorbell
Bits
Name
Description
Reset
Value
PCI
Access
AHB
Access
31:0
PDB
AHB generated doorbell interrupt to PCI. Normally read/write-1-to-set
from AHB and read/write-1-to-clear from PCI. Read/write from the AHB
side if Doorbell Test mode is enabled by setting pci_csr.DBT to a 1.
0x0000
0000
RW1C
RW1S
(RW if
pci_csr.
DBT=1)
Register Name:
pci_atpdma0_ahbaddr
Block
Base Address:
0xC00000
Offset Address
0x40
Reset Value
0x00000000
Register Description:
Source address on the AHB bus for AHB-to-PCI DMA transfers.
Paired with pci_atpdma1_ahbaddr to allow buffering of DMA
transfer requests.
Access:
(See below.)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
address
0
0
Register
pci_atpdma0_ahbaddr
Bits
Name
Description
Reset
Value
PCI
Access
AHB
Access
31:2
address
AHB word address
0x0000
0000
RO
RW
1:0
Lower AHB address bits hard-wired to zero.
00
RO
RO