
4/29/2020
Godson 3A2000 / 3B2000 Processor User Manual
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HT1 controller
7
0xE00_0000_0000
0xFFF_FFFF_FFFF
Unlike the mapping relationship of direction ports, Loongson 3A2000 can decide to share based on the actual application access behavior
Cache cross-addressing mode. The 4 shared Cache modules in the node correspond to a total of 43 bits of address space, and each module
The address space corresponding to the block is determined according to one of the two selection bits of the address bit, and can be dynamically configured and repaired by software
change. The configuration register named SCID_SEL is set in the system to determine the address selection bits, as shown in the following table. By default
In the case of [7: 6] status hash distribution, that is, the two addresses [7: 6] determine the corresponding shared cache number.
The register address is 0x3FF00400.
Table 2-4 Address distribution in nodes
SCID_SEL
Address bit selection
SCID_SEL
Address bit selection
4'h0
7: 6
4'h8
23:22
4'h1
9: 8
4'h9
25:24
4'h2
11:10
4'ha
27:26
4'h3
13:12
4'hb
29:28
4'h4
15:14
4'hc
31:30
4'h5
17:16
4'hd
33:32
4'h6
19:18
4'he
35:34
4'h7
21:20
4'hf
37:36
2.5 Address Routing Distribution and Configuration
The routing of Loongson 3A2000 is mainly realized through the two-stage crossbar of the system. One-level crossbar can
The master port receives requests for routing configuration. Each master port has 8 address windows, which can be completed
Target routing in 8 address windows. Each address window consists of three 64-bit registers BASE, MASK and MMAP,
BASE is aligned in K bytes; MASK adopts a format similar to the high bit of the netmask; the lower three bits of MMAP indicate the corresponding target
Slave port number, MMAP [4] means to allow instruction fetch, MMAP [5] means to allow block read, MMAP [6] means to allow pair
Scache's interleaved access is enabled, MMAP [7] indicates that the window is enabled.
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Godson 3A2000 / 3B2000 Processor User Manual Part 1
Table 2-5 The space access attributes corresponding to the MMAP field
[7]
[6]
[5]
[4]
Window enable allows interleaved access to SCACHE. It is valid when the slave number is 0, according to the above
A section of SCID_SEL configuration routes requests that hit window addresses
Allow block read, allow instruction fetch
Window hit formula: (IN_ADDR & MASK) == BASE
Since Loongson 3 uses fixed routing by default, the configuration window is closed when the power is turned on.
System software is required to enable and configure it.
The address window conversion register is shown in the table below.
Table 2-6 First-level crossbar address window register table
address
register
address
register
0x3ff0_2000 CORE0_WIN0_BASE 0x3ff0_2100 CORE1_WIN0_BASE
0x3ff0_2008 CORE0_WIN1_BASE 0x3ff0_2108 CORE1_WIN1_BASE
0x3ff0_2010 CORE0_WIN2_BASE 0x3ff0_2110 CORE1_WIN2_BASE
0x3ff0_2018 CORE0_WIN3_BASE 0x3ff0_2118 CORE1_WIN3_BASE
0x3ff0_2020 CORE0_WIN4_BASE 0x3ff0_2120 CORE1_WIN4_BASE
0x3ff0_2028 CORE0_WIN5_BASE 0x3ff0_2128 CORE1_WIN5_BASE