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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Develepor’s Manual
Order Number: 306262-004US
575
PCI Controller—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
10.5.3.28 PCI-to-AHB DMA Length Register 1
10.6
Error/Abnormal Conditions
This section describes the behavior of the PCI Controller under various error conditions
that can occur on the PCI and AHB busses.
10.6.1
Error Handling as a PCI Target
10.6.1.0.1
A PCI Target Read Received an Error Response During the AHB Read
Operation and the PCI Transfer is Not Complete
This case occurs when the Target Interface is delivering data to the PCI Initiator and an
abort indication is received from the AHB Master Interface due to an ERROR response
received during the AHB read transfer.
1. The AHB Master terminates the read transfer and stops delivering data to the PCI
Core.
2. The PCI Target delivers all remaining data in the Target Read FIFO to the PCI
Initiator then terminates the cycle with a Target Abort response. With the ECC/
parity implementation of the DDRI and Expansion bus controller on the IXP45X/
IXP46X network processors, if an ECC or parity error exists on any word within an
8-word line (even if the PCI Initiator does not ask for this word), the PCI will
respond with Target Abort on the first word of the read transfer.
3. The PCI Configuration Register pci_srcr.STA bit is set to indicate that this device
signalled a Target Abort.
4. The pci_isr.AHBE CSR bit is set to a 1 to indicate that an AHB error has occurred.
Register Name:
pci_ptadma1_length
Block
Base Address:
0xC00000
Offset Address
0x6c
Reset Value
0x00000000
Register Description:
Provides word count and control for PCI-to-AHB DMA transfers.
Paired with pci_ptadma0_length 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
EN (Rsvd) BE
(Reserved)
wordcount
Register
pci_ptadma1_length
Bits
Name
Description
Reset
Value
PCI
Access
AHB
Access
31
EN
Channel enable. When set to a 1, executes a DMA transfer if wordcount is
nonzero. When 0, the channel is disabled. Hardware clears this bit when
the DMA transfer is complete.
0
RO
RW
30:2
9
reserved
Reserved. Read as 0.
00
RO
RO
28
DS
Data Swap indicator. When set to a 1, data from the PCI bus is byte
swapped before being sent to the AHB bus. When 0, no swapping is done.
0
RO
RW
27:1
6
reserved
Reserved. Read as 0.
0x000
RO
RO
15:0
wordcount
Number of words to transfer.
0x0000
RO
RW