Re: [PATCH V12 03/24] Documentation: LoongArch: Add basic documentations

From: Jiaxun Yang
Date: Wed Jun 01 2022 - 08:16:37 EST

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在2022年6月1日六月上午10:59，Huacai Chen写道：
> 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).
>
> Co-developed-by: WANG Xuerui <git@xxxxxxxxxx>
> Signed-off-by: WANG Xuerui <git@xxxxxxxxxx>
> Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>

Reviewed-by: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>

Did proofread, perfect!
Thanks.

> ---
> Documentation/arch.rst | 1 +
> Documentation/loongarch/features.rst | 3 +
> Documentation/loongarch/index.rst | 21 ++
> Documentation/loongarch/introduction.rst | 387 +++++++++++++++++++++
> Documentation/loongarch/irq-chip-model.rst | 168 +++++++++
> 5 files changed, 580 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 14bcd8294b93..41a66a8b38e4 100644
> --- a/Documentation/arch.rst
> +++ b/Documentation/arch.rst
> @@ -13,6 +13,7 @@ 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:: $srctree/Documentation/features loongarch
> diff --git a/Documentation/loongarch/index.rst
> b/Documentation/loongarch/index.rst
> new file mode 100644
> index 000000000000..aaba648db907
> --- /dev/null
> +++ b/Documentation/loongarch/index.rst
> @@ -0,0 +1,21 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +======================
> +LoongArch Architecture
> +======================
> +
> +.. toctree::
> + :maxdepth: 2
> + :numbered:
> +
> + introduction
> + irq-chip-model
> +
> + features
> +
> +.. only:: subproject and html
> +
> + Indices
> + =======
> +
> + * :ref:`genindex`
> diff --git a/Documentation/loongarch/introduction.rst
> b/Documentation/loongarch/introduction.rst
> new file mode 100644
> index 000000000000..b4df5b459677
> --- /dev/null
> +++ b/Documentation/loongarch/introduction.rst
> @@ -0,0 +1,387 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +=========================
> +Introduction to LoongArch
> +=========================
> +
> +LoongArch is a new RISC ISA, which is a bit like MIPS or RISC-V. There
> are
> +currently 3 variants: a reduced 32-bit version (LA32R), a standard
> 32-bit
> +version (LA32S) and a 64-bit version (LA64). There are 4 privilege
> levels
> +(PLVs) defined in LoongArch: PLV0~PLV3, from high to low. Kernel runs
> at PLV0
> +while applications run at PLV3. This document introduces the
> registers, basic
> +instruction set, virtual memory and some other topics of LoongArch.
> +
> +Registers
> +=========
> +
> +LoongArch registers include general purpose registers (GPRs), floating
> point
> +registers (FPRs), vector registers (VRs) and control status registers
> (CSRs)
> +used in privileged mode (PLV0).
> +
> +GPRs
> +----
> +
> +LoongArch has 32 GPRs ( ``$r0`` ~ ``$r31`` ); each one is 32-bit wide
> in LA32
> +and 64-bit wide in LA64. ``$r0`` is hard-wired to zero, and the other
> registers
> +are not architecturally special. (Except ``$r1``, which is hard-wired
> as the
> +link register of the BL instruction.)
> +
> +The kernel uses a variant of the LoongArch register convention, as
> described in
> +the LoongArch ELF psABI spec, in :ref:`References
> <loongarch-references>`:
> +
> +================= =============== =================== ============
> +Name Alias Usage Preserved
> + across calls
> +================= =============== =================== ============
> +``$r0`` ``$zero`` Constant zero Unused
> +``$r1`` ``$ra`` Return address No
> +``$r2`` ``$tp`` TLS/Thread pointer Unused
> +``$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`` ``$u0`` Percpu base address Unused
> +``$r22`` ``$fp`` Frame pointer Yes
> +``$r23``-``$r31`` ``$s0``-``$s8`` Static registers Yes
> +================= =============== =================== ============
> +
> +Note: The register ``$r21`` is reserved in the ELF psABI, but used by
> the Linux
> +kernel for storing the percpu base address. It normally has no ABI
> name, but is
> +called ``$u0`` in the kernel. You may also see ``$v0`` or ``$v1`` in
> some old code,
> +they are deprecated aliases of ``$a0`` and ``$a1`` respectively.
> +
> +FPRs
> +----
> +
> +LoongArch has 32 FPRs ( ``$f0`` ~ ``$f31`` ) when FPU is present. Each
> one is
> +64-bit wide on the LA64 cores.
> +
> +The floating-point register convention is the same as described in the
> +LoongArch ELF psABI spec:
> +
> +================= ================== =================== ============
> +Name Alias Usage Preserved
> + across calls
> +================= ================== =================== ============
> +``$f0``-``$f7`` ``$fa0``-``$fa7`` Argument registers No
> +``$f0``-``$f1`` ``$fv0``-``$fv1`` Return value No
> +``$f8``-``$f23`` ``$ft0``-``$ft15`` Temp registers No
> +``$f24``-``$f31`` ``$fs0``-``$fs7`` Static registers Yes
> +================= ================== =================== ============
> +
> +Note: You may see ``$fv0`` or ``$fv1`` in some old code, they are
> deprecated
> +aliases of ``$fa0`` and ``$fa1`` respectively.
> +
> +VRs
> +----
> +
> +There are currently 2 vector extensions to LoongArch:
> +
> +- LSX (Loongson SIMD eXtension) with 128-bit vectors,
> +- LASX (Loongson Advanced SIMD eXtension) with 256-bit vectors.
> +
> +LSX brings ``$v0`` ~ ``$v31`` while LASX brings ``$x0`` ~ ``$x31`` as
> the vector
> +registers.
> +
> +The VRs overlap with FPRs: for example, on a core implementing LSX and
> LASX,
> +the lower 128 bits of ``$x0`` is shared with ``$v0``, and the lower 64
> bits of
> +``$v0`` is shared with ``$f0``; same with all other VRs.
> +
> +CSRs
> +----
> +
> +CSRs can only be accessed from privileged mode (PLV0):
> +
> +================= ===================================== ==============
> +Address Full Name Abbrev Name
> +================= ===================================== ==============
> +0x0 Current Mode Information CRMD
> +0x1 Pre-exception Mode Information PRMD
> +0x2 Extension Unit Enable EUEN
> +0x3 Miscellaneous Control MISC
> +0x4 Exception Configuration ECFG
> +0x5 Exception Status ESTAT
> +0x6 Exception Return Address ERA
> +0x7 Bad (Faulting) Virtual Address BADV
> +0x8 Bad (Faulting) Instruction Word BADI
> +0xC Exception Entrypoint 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 Control for Lower- PWCL
> + half Address Space
> +0x1D Page Walk Control 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) Saved Data 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 Control LLBCTL
> +0x80 Implementation-specific Control 1 IMPCTL1
> +0x81 Implementation-specific Control 2 IMPCTL2
> +0x88 TLB Refill Exception Entrypoint TLBRENTRY
> + Address
> +0x89 TLB Refill Exception BAD (Faulting) TLBRBADV
> + Virtual Address
> +0x8A TLB Refill Exception Return Address TLBRERA
> +0x8B TLB Refill Exception Saved Data 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 Control MERRCTL
> +0x91 Machine Error Information 1 MERRINFO1
> +0x92 Machine Error Information 2 MERRINFO2
> +0x93 Machine Error Exception Entrypoint MERRENTRY
> + Address
> +0x94 Machine Error Exception Return MERRERA
> + Address
> +0x95 Machine Error Exception Saved Data 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 Control
> +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 Instruction Fetch WatchPoint FWPC
> + Overall Control
> +0x381 Instruction Fetch WatchPoint FWPS
> + Overall Status
> +0x390+8n (0≤n≤7) Instruction Fetch WatchPoint n FWPnCFG1
> + Configuration 1
> +0x391+8n (0≤n≤7) Instruction Fetch WatchPoint n FWPnCFG2
> + Configuration 2
> +0x392+8n (0≤n≤7) Instruction Fetch WatchPoint n FWPnCFG3
> + Configuration 3
> +0x393+8n (0≤n≤7) Instruction Fetch WatchPoint n FWPnCFG4
> + Configuration 4
> +0x500 Debug Register DBG
> +0x501 Debug Exception Return Address DERA
> +0x502 Debug Exception Saved Data Register DSAVE
> +================= ===================================== ==============
> +
> +ERA, TLBRERA, MERRERA and DERA are sometimes also known as EPC,
> TLBREPC, MERREPC
> +and DEPC respectively.
> +
> +Basic Instruction Set
> +=====================
> +
> +Instruction formats
> +-------------------
> +
> +LoongArch instructions are 32 bits wide, belonging to 9 basic
> instruction
> +formats (and variants of them):
> +
> +=========== ==========================
> +Format name Composition
> +=========== ==========================
> +2R Opcode + Rj + Rd
> +3R Opcode + Rk + Rj + Rd
> +4R Opcode + Ra + Rk + Rj + Rd
> +2RI8 Opcode + I8 + Rj + Rd
> +2RI12 Opcode + I12 + Rj + Rd
> +2RI14 Opcode + I14 + Rj + Rd
> +2RI16 Opcode + I16 + Rj + Rd
> +1RI21 Opcode + I21L + Rj + I21H
> +I26 Opcode + I26L + I26H
> +=========== ==========================
> +
> +Rd is the destination register operand, while Rj, Rk and Ra ("a"
> stands for
> +"additional") are the source register operands. I8/I12/I16/I21/I26 are
> +immediate operands of respective width. The longer I21 and I26 are
> stored
> +in separate higher and lower parts in the instruction word, denoted by
> the "L"
> +and "H" suffixes.
> +
> +List of Instructions
> +--------------------
> +
> +For brevity, only instruction names (mnemonics) are listed here;
> please see the
> +:ref:`References <loongarch-references>` for details.
> +
> +
> +1. Arithmetic 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
> +
> +2. 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
> +
> +3. 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
> +
> +4. Branch Instructions::
> +
> + BEQ BNE BLT BGE BLTU BGEU BEQZ BNEZ B BL JIRL
> +
> +5. 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
> +
> +6. 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
> +
> +7. Barrier Instructions::
> +
> + IBAR DBAR
> +
> +8. Special Instructions::
> +
> + SYSCALL BREAK CPUCFG NOP IDLE ERTN(ERET) DBCL(DBGCALL) RDTIMEL.W
> RDTIMEH.W RDTIME.D
> + ASRTLE.D ASRTGT.D
> +
> +9. 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 supports 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 bits 60~63 cleared, and the cache
> attribute
> +is configured by bits 60~61 in VA: 0 is for strongly-ordered uncached,
> 1 is
> +for coherent cached, and 2 is for weakly-ordered uncached.
> +
> +Currently we only use XKPRANGE for direct mapping and XSPRANGE is
> reserved.
> +
> +To put this in action: 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.
> +
> +.. _loongarch-references:
> +
> +References
> +==========
> +
> +Official web site of Loongson Technology Corp. Ltd.:
> +
> + http://www.loongson.cn/
> +
> +Developer web site of Loongson and LoongArch (Software and
> Documentation):
> +
> + http://www.loongnix.cn/
> +
> + https://github.com/loongson/
> +
> + https://loongson.github.io/LoongArch-Documentation/
> +
> +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 psABI:
> +
> +
> 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..35c962991283
> --- /dev/null
> +++ b/Documentation/loongarch/irq-chip-model.rst
> @@ -0,0 +1,168 @@
> +.. 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)
> +
> +Note: CPUINTC is CSR.ECFG/CSR.ESTAT and its interrupt controller
> described
> +in Section 7.4 of "LoongArch Reference Manual, Vol 1"; LIOINTC is
> "Legacy I/O
> +Interrupts" described in Section 11.1 of "Loongson 3A5000 Processor
> Reference
> +Manual"; EIOINTC is "Extended I/O Interrupts" described in Section
> 11.2 of
> +"Loongson 3A5000 Processor Reference Manual"; HTVECINTC is
> "HyperTransport
> +Interrupts" described in Section 14.3 of "Loongson 3A5000 Processor
> Reference
> +Manual"; PCH-PIC/PCH-MSI is "Interrupt Controller" described in
> Section 5 of
> +"Loongson 7A1000 Bridge User Manual"; PCH-LPC is "LPC Interrupts"
> described in
> +Section 24.3 of "Loongson 7A1000 Bridge User Manual".
> --
> 2.27.0

--
- Jiaxun

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