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linux/Documentation/arch/loongarch/irq-chip-model.rst
Huacai Chen f339bd3b51 Docs/LoongArch: Add advanced extended IRQ model description
Introduce the advanced extended interrupt controllers (AVECINTC). This
feature will allow each core to have 256 independent interrupt vectors
and MSI interrupts can be independently routed to any vector on any CPU.

The whole topology of irqchips in LoongArch machines looks like this if
AVECINTC is supported:

  +-----+     +-----------------------+     +-------+
  | IPI | --> |        CPUINTC        | <-- | Timer |
  +-----+     +-----------------------+     +-------+
               ^          ^          ^
               |          |          |
        +---------+ +----------+ +---------+     +-------+
        | EIOINTC | | AVECINTC | | LIOINTC | <-- | UARTs |
        +---------+ +----------+ +---------+     +-------+
             ^            ^
             |            |
        +---------+  +---------+
        | PCH-PIC |  | PCH-MSI |
        +---------+  +---------+
          ^     ^           ^
          |     |           |
  +---------+ +---------+ +---------+
  | Devices | | PCH-LPC | | Devices |
  +---------+ +---------+ +---------+
                   ^
                   |
              +---------+
              | Devices |
              +---------+

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Tianyang Zhang <zhangtianyang@loongson.cn>
2024-09-24 15:32:20 +08:00

193 lines
6.4 KiB
ReStructuredText

.. 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 |
+---------+
Advanced 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, PCH-MSI interrupts go
to AVECINTC, and then go to CPUINTC directly, while all other devices interrupts
go to PCH-PIC/PCH-LPC and gathered by EIOINTC, and then go to CPUINTC directly::
+-----+ +-----------------------+ +-------+
| IPI | --> | CPUINTC | <-- | Timer |
+-----+ +-----------------------+ +-------+
^ ^ ^
| | |
+---------+ +----------+ +---------+ +-------+
| EIOINTC | | AVECINTC | | LIOINTC | <-- | UARTs |
+---------+ +----------+ +---------+ +-------+
^ ^
| |
+---------+ +---------+
| PCH-PIC | | PCH-MSI |
+---------+ +---------+
^ ^ ^
| | |
+---------+ +---------+ +---------+
| Devices | | PCH-LPC | | 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/OInterrupts" 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".