[PATCH V4 01/22] Documentation: LoongArch: Add basic documentations
From: Huacai Chen
Date: Mon Sep 27 2021 - 02:45:26 EST
Add some basic documentation for LoongArch. LoongArch is a new RISC ISA,
which is a bit like MIPS or RISC-V. LoongArch includes a reduced 32-bit
version (LA32R), a standard 32-bit version (LA32S) and a 64-bit version
(LA64).
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
---
Documentation/arch.rst | 1 +
Documentation/loongarch/features.rst | 3 +
Documentation/loongarch/index.rst | 21 ++
Documentation/loongarch/introduction.rst | 342 +++++++++++++++++++++
Documentation/loongarch/irq-chip-model.rst | 158 ++++++++++
5 files changed, 525 insertions(+)
create mode 100644 Documentation/loongarch/features.rst
create mode 100644 Documentation/loongarch/index.rst
create mode 100644 Documentation/loongarch/introduction.rst
create mode 100644 Documentation/loongarch/irq-chip-model.rst
diff --git a/Documentation/arch.rst b/Documentation/arch.rst
index f10bd32a5972..ed6956289e4d 100644
--- a/Documentation/arch.rst
+++ b/Documentation/arch.rst
@@ -12,6 +12,7 @@ implementation.
arm/index
arm64/index
ia64/index
+ loongarch/index
m68k/index
mips/index
nios2/index
diff --git a/Documentation/loongarch/features.rst b/Documentation/loongarch/features.rst
new file mode 100644
index 000000000000..ebacade3ea45
--- /dev/null
+++ b/Documentation/loongarch/features.rst
@@ -0,0 +1,3 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+.. kernel-feat:: $srctree/Documentation/features loongarch
diff --git a/Documentation/loongarch/index.rst b/Documentation/loongarch/index.rst
new file mode 100644
index 000000000000..d127e07a7ed3
--- /dev/null
+++ b/Documentation/loongarch/index.rst
@@ -0,0 +1,21 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+================================
+LoongArch-specific Documentation
+================================
+
+.. toctree::
+ :maxdepth: 2
+ :numbered:
+
+ introduction
+ irq-chip-model
+
+ features
+
+.. only:: subproject and html
+
+ Indices
+ =======
+
+ * :ref:`genindex`
diff --git a/Documentation/loongarch/introduction.rst b/Documentation/loongarch/introduction.rst
new file mode 100644
index 000000000000..888ba67fcc1b
--- /dev/null
+++ b/Documentation/loongarch/introduction.rst
@@ -0,0 +1,342 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=========================
+Introduction of LoongArch
+=========================
+
+LoongArch is a new RISC ISA, which is a bit like MIPS or RISC-V. LoongArch
+includes a reduced 32-bit version (LA32R), a standard 32-bit version (LA32S)
+and a 64-bit version (LA64). LoongArch has 4 privilege levels (PLV0~PLV3),
+PLV0 is the highest level which used by kernel, and PLV3 is the lowest level
+which used by applications. This document introduces the registers, basic
+instruction set, virtual memory and some other topics of LoongArch.
+
+Registers
+=========
+
+LoongArch registers include general purpose registers (GPRs), floating point
+registers (FPRs), vector registers (VRs) and control status registers (CSRs)
+used in privileged mode (PLV0).
+
+GPRs
+----
+
+LoongArch has 32 GPRs ($r0 - $r31), each one is 32bit wide in LA32 and 64bit
+wide in LA64. $r0 is always zero, and other registers has no special feature,
+but we actually have an ABI register convention as below.
+
+================= =============== =================== ============
+Name Alias Usage Preserved
+ across calls
+================= =============== =================== ============
+``$r0`` ``$zero`` Constant zero Unused
+``$r1`` ``$ra`` Return address No
+``$r2`` ``$tp`` TLS Unused
+``$r3`` ``$sp`` Stack pointer Yes
+``$r4``-``$r11`` ``$a0``-``$a7`` Argument registers No
+``$r4``-``$r5`` ``$v0``-``$v1`` Return value No
+``$r12``-``$r20`` ``$t0``-``$t8`` Temp registers No
+``$r21`` ``$x`` Reserved Unused
+``$r22`` ``$fp`` Frame pointer Yes
+``$r23``-``$r31`` ``$s0``-``$s8`` Static registers Yes
+================= =============== =================== ============
+
+FPRs
+----
+
+LoongArch has 32 FPRs ($f0 - $f31), each one is 64bit wide. We also have an
+ABI register conversion as below.
+
+================= ================== =================== ============
+Name Alias Usage Preserved
+ across calls
+================= ================== =================== ============
+``$f0``-``$f7`` ``$fa0``-``$fa7`` Argument registers No
+``$f0``-``$f1`` ``$fv0``-``$fv1`` Return value No
+``$f8``-``$f23`` ``$ft0``-``$ft15`` Temp registers No
+``$f24``-``$f31`` ``$fs0``-``$fs7`` Static registers Yes
+================= ================== =================== ============
+
+VRs
+----
+
+LoongArch has 128bit vector extension (LSX, short for Loongson SIMD eXtention)
+and 256bit vector extension (LASX, short for Loongson Advanced SIMD eXtension).
+There are also 32 vector registers, for LSX is $v0 - $v31, and for LASX is $x0
+- $x31. FPRs and VRs are reused, e.g. the lower 128bits of $x0 is $v0, and the
+lower 64bits of $v0 is $f0, etc.
+
+CSRs
+----
+
+CSRs can only be used in privileged mode (PLV0):
+
+================= ===================================== ==============
+Address Full Name Abbrev Name
+================= ===================================== ==============
+0x0 Current Mode information CRMD
+0x1 Pre-exception Mode information PRMD
+0x2 Extended Unit Enable EUEN
+0x3 Miscellaneous controller MISC
+0x4 Exception Configuration ECFG
+0x5 Exception Status ESTAT
+0x6 Exception Return Address ERA
+0x7 Bad Virtual Address BADV
+0x8 Bad Instruction BADI
+0xC Exception Entry Base address EENTRY
+0x10 TLB Index TLBIDX
+0x11 TLB Entry High-order bits TLBEHI
+0x12 TLB Entry Low-order bits 0 TLBELO0
+0x13 TLB Entry Low-order bits 1 TLBELO1
+0x18 Address Space Identifier ASID
+0x19 Page Global Directory address for PGDL
+ Lower half address space
+0x1A Page Global Directory address for PGDH
+ Higher half address space
+0x1B Page Global Directory address PGD
+0x1C Page Walk Controller for Lower PWCL
+ half address space
+0x1D Page Walk Controller for Higher PWCH
+ half address space
+0x1E STLB Page Size STLBPS
+0x1F Reduced Virtual Address Configuration RVACFG
+0x20 CPU Identifier CPUID
+0x21 Privileged Resource Configuration 1 PRCFG1
+0x22 Privileged Resource Configuration 2 PRCFG2
+0x23 Privileged Resource Configuration 3 PRCFG3
+0x30+n (0≤n≤15) Data Save register SAVEn
+0x40 Timer Identifier TID
+0x41 Timer Configuration TCFG
+0x42 Timer Value TVAL
+0x43 Compensation of Timer Count CNTC
+0x44 Timer Interrupt Clearing TICLR
+0x60 LLBit Controller LLBCTL
+0x80 Implementation-specific Controller 1 IMPCTL1
+0x81 Implementation-specific Controller 2 IMPCTL2
+0x88 TLB Refill Exception Entry Base TLBRENTRY
+ address
+0x89 TLB Refill Exception BAD Virtual TLBRBADV
+ address
+0x8A TLB Refill Exception Return Address TLBRERA
+0x8B TLB Refill Exception data SAVE TLBRSAVE
+ register
+0x8C TLB Refill Exception Entry Low-order TLBRELO0
+ bits 0
+0x8D TLB Refill Exception Entry Low-order TLBRELO1
+ bits 1
+0x8E TLB Refill Exception Entry High-order TLBEHI
+ bits
+0x8F TLB Refill Exception Pre-exception TLBRPRMD
+ Mode information
+0x90 Machine Error Controller MERRCTL
+0x91 Machine Error Information 1 MERRINFO1
+0x92 Machine Error Information 2 MERRINFO2
+0x93 Machine Error Exception Entry Base MERRENTRY
+ address
+0x94 Machine Error Exception Return MERRERA
+ address
+0x95 Machine Error Exception data SAVE MERRSAVE
+ register
+0x98 Cache TAGs CTAG
+0x180+n (0≤n≤3) Direct Mapping configuration Window n DMWn
+0x200+2n (0≤n≤31) Performance Monitor Configuration n PMCFGn
+0x201+2n (0≤n≤31) Performance Monitor overall Counter n PMCNTn
+0x300 Memory load/store WatchPoint MWPC
+ overall Controller
+0x301 Memory load/store WatchPoint MWPS
+ overall Status
+0x310+8n (0≤n≤7) Memory load/store WatchPoint n MWPnCFG1
+ Configuration 1
+0x311+8n (0≤n≤7) Memory load/store WatchPoint n MWPnCFG2
+ Configuration 2
+0x312+8n (0≤n≤7) Memory load/store WatchPoint n MWPnCFG3
+ Configuration 3
+0x313+8n (0≤n≤7) Memory load/store WatchPoint n MWPnCFG4
+ Configuration 4
+0x380 Fetch WatchPoint overall Controller FWPC
+0x381 Fetch WatchPoint overall Status FWPS
+0x390+8n (0≤n≤7) Fetch WatchPoint n Configuration 1 FWPnCFG1
+0x391+8n (0≤n≤7) Fetch WatchPoint n Configuration 2 FWPnCFG2
+0x392+8n (0≤n≤7) Fetch WatchPoint n Configuration 3 FWPnCFG3
+0x393+8n (0≤n≤7) Fetch WatchPoint n Configuration 4 FWPnCFG4
+0x500 Debug register DBG
+0x501 Debug Exception Return address DERA
+0x502 Debug data SAVE register DSAVE
+================= ===================================== ==============
+
+Basic Instruction Set
+=====================
+
+Instruction formats
+-------------------
+
+LoongArch has 32-bit wide instructions, and there are 9 instruction formats::
+
+ 2R-type: Opcode + Rj + Rd
+ 3R-type: Opcode + Rk + Rj + Rd
+ 4R-type: Opcode + Ra + Rk + Rj + Rd
+ 2RI8-type: Opcode + I8 + Rj + Rd
+ 2RI12-type: Opcode + I12 + Rj + Rd
+ 2RI14-type: Opcode + I14 + Rj + Rd
+ 2RI16-type: Opcode + I16 + Rj + Rd
+ 1RI21-type: Opcode + I21L + Rj + I21H
+ I26-type: Opcode + I26L + I26H
+
+Rj and Rk are source operands (register), Rd is destination operand (register),
+and Ra is the additional operand (register) in 4R-type. I8/I12/I16/I21/I26 are
+8-bits/12-bits/16-bits/21-bits/26bits immediate data. 21bits/26bits immediate
+data are split into higher bits and lower bits in an instruction word, so you
+can see I21L/I21H and I26L/I26H here.
+
+Instruction names (Mnemonics)
+-----------------------------
+
+We only list the instruction names here, for details please read the references.
+
+Arithmetic Operation Instructions::
+
+ ADD.W SUB.W ADDI.W ADD.D SUB.D ADDI.D
+ SLT SLTU SLTI SLTUI
+ AND OR NOR XOR ANDN ORN ANDI ORI XORI
+ MUL.W MULH.W MULH.WU DIV.W DIV.WU MOD.W MOD.WU
+ MUL.D MULH.D MULH.DU DIV.D DIV.DU MOD.D MOD.DU
+ PCADDI PCADDU12I PCADDU18I
+ LU12I.W LU32I.D LU52I.D ADDU16I.D
+
+Bit-shift Instructions::
+
+ SLL.W SRL.W SRA.W ROTR.W SLLI.W SRLI.W SRAI.W ROTRI.W
+ SLL.D SRL.D SRA.D ROTR.D SLLI.D SRLI.D SRAI.D ROTRI.D
+
+Bit-manipulation Instructions::
+
+ EXT.W.B EXT.W.H CLO.W CLO.D SLZ.W CLZ.D CTO.W CTO.D CTZ.W CTZ.D
+ BYTEPICK.W BYTEPICK.D BSTRINS.W BSTRINS.D BSTRPICK.W BSTRPICK.D
+ REVB.2H REVB.4H REVB.2W REVB.D REVH.2W REVH.D BITREV.4B BITREV.8B BITREV.W BITREV.D
+ MASKEQZ MASKNEZ
+
+Branch Instructions::
+
+ BEQ BNE BLT BGE BLTU BGEU BEQZ BNEZ B BL JIRL
+
+Load/Store Instructions::
+
+ LD.B LD.BU LD.H LD.HU LD.W LD.WU LD.D ST.B ST.H ST.W ST.D
+ LDX.B LDX.BU LDX.H LDX.HU LDX.W LDX.WU LDX.D STX.B STX.H STX.W STX.D
+ LDPTR.W LDPTR.D STPTR.W STPTR.D
+ PRELD PRELDX
+
+Atomic Operation Instructions::
+
+ LL.W SC.W LL.D SC.D
+ AMSWAP.W AMSWAP.D AMADD.W AMADD.D AMAND.W AMAND.D AMOR.W AMOR.D AMXOR.W AMXOR.D
+ AMMAX.W AMMAX.D AMMIN.W AMMIN.D
+
+Barrier Instructions::
+
+ IBAR DBAR
+
+Special Instructions::
+
+ SYSCALL BREAK CPUCFG NOP IDLE ERTN DBCL RDTIMEL.W RDTIMEH.W RDTIME.D ASRTLE.D ASRTGT.D
+
+Privileged Instructions::
+
+ CSRRD CSRWR CSRXCHG
+ IOCSRRD.B IOCSRRD.H IOCSRRD.W IOCSRRD.D IOCSRWR.B IOCSRWR.H IOCSRWR.W IOCSRWR.D
+ CACOP TLBP(TLBSRCH) TLBRD TLBWR TLBFILL TLBCLR TLBFLUSH INVTLB LDDIR LDPTE
+
+Virtual Memory
+==============
+
+LoongArch can use direct-mapped virtual memory and page-mapped virtual memory.
+
+Direct-mapped virtual memory is configured by CSR.DMWn (n=0~3), it has a simple
+relationship between virtual address (VA) and physical address (PA)::
+
+ VA = PA + FixedOffset
+
+Page-mapped virtual memory has arbitrary relationship between VA and PA, which
+is recorded in TLB and page tables. LoongArch's TLB includes a fully-associative
+MTLB (Multiple Page Size TLB) and set-associative STLB (Single Page Size TLB).
+
+By default, the whole virtual address space of LA32 is configured like this:
+
+============ =========================== =============================
+Name Address Range Attributes
+============ =========================== =============================
+``UVRANGE`` ``0x00000000 - 0x7FFFFFFF`` Page-mapped, Cached, PLV0~3
+``KPRANGE0`` ``0x80000000 - 0x9FFFFFFF`` Direct-mapped, Uncached, PLV0
+``KPRANGE1`` ``0xA0000000 - 0xBFFFFFFF`` Direct-mapped, Cached, PLV0
+``KVRANGE`` ``0xC0000000 - 0xFFFFFFFF`` Page-mapped, Cached, PLV0
+============ =========================== =============================
+
+User mode (PLV3) can only access UVRANGE. For direct-mapped KPRANGE0 and
+KPRANGE1, PA is equal to VA with bit30~31 cleared. For example, the uncached
+direct-mapped VA of 0x00001000 is 0x80001000, and the cached direct-mapped
+VA of 0x00001000 is 0xA0001000.
+
+By default, the whole virtual address space of LA64 is configured like this:
+
+============ ====================== ======================================
+Name Address Range Attributes
+============ ====================== ======================================
+``XUVRANGE`` ``0x0000000000000000 - Page-mapped, Cached, PLV0~3
+ 0x3FFFFFFFFFFFFFFF``
+``XSPRANGE`` ``0x4000000000000000 - Direct-mapped, Cached / Uncached, PLV0
+ 0x7FFFFFFFFFFFFFFF``
+``XKPRANGE`` ``0x8000000000000000 - Direct-mapped, Cached / Uncached, PLV0
+ 0xBFFFFFFFFFFFFFFF``
+``XKVRANGE`` ``0xC000000000000000 - Page-mapped, Cached, PLV0
+ 0xFFFFFFFFFFFFFFFF``
+============ ====================== ======================================
+
+User mode (PLV3) can only access XUVRANGE. For direct-mapped XSPRANGE and XKPRANGE,
+PA is equal to VA with bit60~63 cleared, and the cache attributes is configured by
+bit60~61 (0 is strongly-ordered uncached, 1 is coherent cached, and 2 is weakly-
+ordered uncached) in VA. Currently we only use XKPRANGE for direct mapping and
+XSPRANGE is reserved. As an example, the strongly-ordered uncached direct-mapped VA
+(in XKPRANGE) of 0x00000000 00001000 is 0x80000000 00001000, the coherent cached
+direct-mapped VA (in XKPRANGE) of 0x00000000 00001000 is 0x90000000 00001000, and
+the weakly-ordered uncached direct-mapped VA (in XKPRANGE) of 0x00000000 00001000
+is 0xA0000000 00001000.
+
+Relationship of Loongson and LoongArch
+======================================
+
+LoongArch is a RISC ISA which is different from any other existing ones, while
+Loongson is a family of processors. Loongson includes 3 series: Loongson-1 is
+the 32-bit processor series, Loongson-2 is the low-end 64-bit processor series,
+and Loongson-3 is the high-end 64-bit processor series. Old Loongson is based on
+MIPS, while New Loongson is based on LoongArch. Take Loongson-3 as an example:
+Loongson-3A1000/3B1500/3A2000/3A3000/3A4000 are MIPS-compatible, while Loongson-
+3A5000 (and future revisions) are all based on LoongArch.
+
+References
+==========
+
+Official web site of Loongson and LoongArch (Loongson Technology Corp. Ltd.):
+
+ http://www.loongson.cn/index.html
+
+Developer web site of Loongson and LoongArch (Software and Documentation):
+
+ http://www.loongnix.cn/index.php
+
+ https://github.com/loongson
+
+Documentation of LoongArch ISA:
+
+ https://github.com/loongson/LoongArch-Documentation/releases/latest/download/LoongArch-Vol1-v1.00-CN.pdf (in Chinese)
+
+ https://github.com/loongson/LoongArch-Documentation/releases/latest/download/LoongArch-Vol1-v1.00-EN.pdf (in English)
+
+Documentation of LoongArch ELF ABI:
+
+ https://github.com/loongson/LoongArch-Documentation/releases/latest/download/LoongArch-ELF-ABI-v1.00-CN.pdf (in Chinese)
+
+ https://github.com/loongson/LoongArch-Documentation/releases/latest/download/LoongArch-ELF-ABI-v1.00-EN.pdf (in English)
+
+Linux kernel repository of Loongson and LoongArch:
+
+ https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson.git
diff --git a/Documentation/loongarch/irq-chip-model.rst b/Documentation/loongarch/irq-chip-model.rst
new file mode 100644
index 000000000000..67dec56b84f2
--- /dev/null
+++ b/Documentation/loongarch/irq-chip-model.rst
@@ -0,0 +1,158 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=======================================
+IRQ chip model (hierarchy) of LoongArch
+=======================================
+
+Currently, LoongArch based processors (e.g. Loongson-3A5000) can only work together
+with LS7A chipsets. The irq chips in LoongArch computers include CPUINTC (CPU Core
+Interrupt Controller), LIOINTC (Legacy I/O Interrupt Controller), EIOINTC (Extended
+I/O Interrupt Controller), HTVECINTC (Hyper-Transport Vector Interrupt Controller),
+PCH-PIC (Main Interrupt Controller in LS7A chipset), PCH-LPC (LPC Interrupt Controller
+in LS7A chipset) and PCH-MSI (MSI Interrupt Controller).
+
+CPUINTC is a per-core controller (in CPU), LIOINTC/EIOINTC/HTVECINTC are per-package
+controllers (in CPU), while PCH-PIC/PCH-LPC/PCH-MSI are controllers out of CPU (i.e.,
+in chipsets). These controllers (in other words, irqchips) are linked in a hierarchy,
+and there are two models of hierarchy (legacy model and extended model).
+
+Legacy IRQ model
+================
+
+In this model, IPI (Inter-Processor Interrupt) and CPU Local Timer interrupt go
+to CPUINTC directly, CPU UARTS interrupts go to LIOINTC, while all other devices
+interrupts go to PCH-PIC/PCH-LPC/PCH-MSI and gathered by HTVECINTC, and then go
+to LIOINTC, and then CPUINTC.
+
+ +---------------------------------------------+
+ |:: |
+ | |
+ | +-----+ +---------+ +-------+ |
+ | | IPI | --> | CPUINTC | <-- | Timer | |
+ | +-----+ +---------+ +-------+ |
+ | ^ |
+ | | |
+ | +---------+ +-------+ |
+ | | LIOINTC | <-- | UARTs | |
+ | +---------+ +-------+ |
+ | ^ |
+ | | |
+ | +-----------+ |
+ | | HTVECINTC | |
+ | +-----------+ |
+ | ^ ^ |
+ | | | |
+ | +---------+ +---------+ |
+ | | PCH-PIC | | PCH-MSI | |
+ | +---------+ +---------+ |
+ | ^ ^ ^ |
+ | | | | |
+ | +---------+ +---------+ +---------+ |
+ | | PCH-LPC | | Devices | | Devices | |
+ | +---------+ +---------+ +---------+ |
+ | ^ |
+ | | |
+ | +---------+ |
+ | | Devices | |
+ | +---------+ |
+ | |
+ | |
+ +---------------------------------------------+
+
+Extended IRQ model
+==================
+
+In this model, IPI (Inter-Processor Interrupt) and CPU Local Timer interrupt go
+to CPUINTC directly, CPU UARTS interrupts go to LIOINTC, while all other devices
+interrupts go to PCH-PIC/PCH-LPC/PCH-MSI and gathered by EIOINTC, and then go to
+to CPUINTC directly.
+
+ +--------------------------------------------------------+
+ |:: |
+ | |
+ | +-----+ +---------+ +-------+ |
+ | | IPI | --> | CPUINTC | <-- | Timer | |
+ | +-----+ +---------+ +-------+ |
+ | ^ ^ |
+ | | | |
+ | +---------+ +---------+ +-------+ |
+ | | EIOINTC | | LIOINTC | <-- | UARTs | |
+ | +---------+ +---------+ +-------+ |
+ | ^ ^ |
+ | | | |
+ | +---------+ +---------+ |
+ | | PCH-PIC | | PCH-MSI | |
+ | +---------+ +---------+ |
+ | ^ ^ ^ |
+ | | | | |
+ | +---------+ +---------+ +---------+ |
+ | | PCH-LPC | | Devices | | Devices | |
+ | +---------+ +---------+ +---------+ |
+ | ^ |
+ | | |
+ | +---------+ |
+ | | Devices | |
+ | +---------+ |
+ | |
+ | |
+ +--------------------------------------------------------+
+
+ACPI-related definitions
+========================
+
+CPUINTC::
+
+ ACPI_MADT_TYPE_CORE_PIC;
+ struct acpi_madt_core_pic;
+ enum acpi_madt_core_pic_version;
+
+LIOINTC::
+
+ ACPI_MADT_TYPE_LIO_PIC;
+ struct acpi_madt_lio_pic;
+ enum acpi_madt_lio_pic_version;
+
+EIOINTC::
+
+ ACPI_MADT_TYPE_EIO_PIC;
+ struct acpi_madt_eio_pic;
+ enum acpi_madt_eio_pic_version;
+
+HTVECINTC::
+
+ ACPI_MADT_TYPE_HT_PIC;
+ struct acpi_madt_ht_pic;
+ enum acpi_madt_ht_pic_version;
+
+PCH-PIC::
+
+ ACPI_MADT_TYPE_BIO_PIC;
+ struct acpi_madt_bio_pic;
+ enum acpi_madt_bio_pic_version;
+
+PCH-MSI::
+
+ ACPI_MADT_TYPE_MSI_PIC;
+ struct acpi_madt_msi_pic;
+ enum acpi_madt_msi_pic_version;
+
+PCH-LPC::
+
+ ACPI_MADT_TYPE_LPC_PIC;
+ struct acpi_madt_lpc_pic;
+ enum acpi_madt_lpc_pic_version;
+
+References
+==========
+
+Documentation of Loongson-3A5000:
+
+ https://github.com/loongson/LoongArch-Documentation/releases/latest/download/Loongson-3A5000-usermanual-1.02-CN.pdf (in Chinese)
+
+ https://github.com/loongson/LoongArch-Documentation/releases/latest/download/Loongson-3A5000-usermanual-1.02-EN.pdf (in English)
+
+Documentation of Loongson's LS7A chipset:
+
+ https://github.com/loongson/LoongArch-Documentation/releases/latest/download/Loongson-7A1000-usermanual-2.00-CN.pdf (in Chinese)
+
+ https://github.com/loongson/LoongArch-Documentation/releases/latest/download/Loongson-7A1000-usermanual-2.00-EN.pdf (in English)
--
2.27.0