4/29/2020
Godson 3A1000 Processor User Manual
90
BIST
Header Type
Latency Timer
CacheLine Size
0C
Base Address Register 0
10
Base Address Register 1
14
Base Address Register 2
18
Base Address Register 3
1C
Base Address Register 4
20
Base Address Register 5
twenty four
28
Subsystem ID
Subsystem Vendor ID
2C
30
Capabilities Pointer
34
38
Maximum Latency
Minimum Grant
Interrupt Pin
Interrupt Line
3C
Implementation Specific Register (ISR40)
40
Implementation Specific Register (ISR44)
44
Implementation Specific Register (ISR48)
48
Implementation Specific Register (ISR4C)
4C
Implementation Specific Register (ISR50)
50
Implementation Specific Register (ISR54)
54
Implementation Specific Register (ISR58)
58
...
PCIX Command Register
E0
PCIX Status Register
E4
99
Page 112
Godson 3A1000 Processor User Manual Part 1
The PCIX controller of Loongson 3A1000 supports three 64-bit windows, composed of {BAR1, BAR0}, {BAR3, BAR2},
{BAR5, BAR4} The base address of three pairs of register configuration windows 0, 1, 2. The size, enable, and other details of the
The three corresponding registers PCI_Hit0_Sel, PCI_Hit1_Sel, PCI_Hit2_Sel control, please refer to Table 2 for specific bit fields.
Table 10-2 PCI Control Register
Bit field
Field name
access
Reset
value
Explanation
REG_40
31 tar_read_io
Read and write
(Write 1
clear)
0
Target end receives access to IO or non-prefetchable area
30 tar_read_discard
Read and write
(Write 1
clear)
0
The delay request on the target side is discarded
29 tar_resp_delay
Read and write
0
When target access is given delay / split
0: After timeout
1: right away
28 tar_delay_retry
Read and write
0
target access retry strategy
0: According to internal logic (see bit 29)
1: Retry now
27 tar_read_abort_en
Read and write
0
If the target times out for internal read requests, whether to let target-abort respond
26:25 Reserved
-
0
24 tar_write_abort_en
Read and write
0
If the target's internal write request times out, whether to respond with target-abort
23 tar_master_abort
Read and write
0
Whether to allow master-abort
22:20 tar_subseq_timeout
Read and write
000
target subsequent delay timeout
000: 8 cycles
Other: Not supported
target initial delay timeout
In PCI mode
0: 16 cycles