Docs/LoongArch: Add advanced extended IRQ model

Introduce a new advanced extended interrupt model with redirect interrupt
controllers. When the redirect interrupt controller is enabled, the routing
target of MSI interrupts is no longer a specific CPU and vector number, but
a specific redirect entry. The actual CPU and vector number used are
described by the redirect entry.

Signed-off-by: Tianyang Zhang <zhangtianyang@loongson.cn>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Acked-by: Huacai Chen <chenhuacai@loongson.cn>
Link: https://patch.msgid.link/20260513012839.2856463-2-zhangtianyang@loongson.cn

Documentation/arch/loongarch/irq-chip-model.rst

@@ -181,6 +181,41 @@ go to PCH-PIC/PCH-LPC and gathered by EIOINTC, and then go to CPUINTC directly::
              | Devices |
              +---------+
 
+Advanced Extended IRQ model (with redirection)
+==============================================
+
+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 REDIRECT for remapping it 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 |
+ +-----+     +-----------------------+     +-------+
+              ^          ^          ^
+              |          |          |
+              |    +----------+     |
+       +---------+ | AVECINTC | +---------+     +-------+
+       | EIOINTC | +----------+ | LIOINTC | <-- | UARTs |
+       +---------+ | REDIRECT | +---------+     +-------+
+            ^      +----------+
+            |            ^
+            |            |
+       +---------+  +---------+
+       | PCH-PIC |  | PCH-MSI |
+       +---------+  +---------+
+         ^     ^           ^
+         |     |           |
+ +---------+ +---------+ +---------+
+ | Devices | | PCH-LPC | | Devices |
+ +---------+ +---------+ +---------+
+                  ^
+                  |
+             +---------+
+             | Devices |
+             +---------+
+
 ACPI-related definitions
 ========================
 

Documentation/translations/zh_CN/arch/loongarch/irq-chip-model.rst

@@ -174,6 +174,40 @@ CPU串口（UARTs）中断发送到LIOINTC，PCH-MSI中断发送到AVECINTC，
              | Devices |
              +---------+
 
+高级扩展IRQ模型 (带重定向)
+==========================
+
+在这种模型里面，IPI（Inter-Processor Interrupt）和CPU本地时钟中断直接发送到CPUINTC，
+CPU串口（UARTs）中断发送到LIOINTC，PCH-MSI中断首先发送到REDIRECT模块,完成重定向后发
+送到AVECINTC，而后通过AVECINTC直接送达CPUINTC，而其他所有设备的中断则分别发送到所连
+接的PCH-PIC/PCH-LPC，然后由EIOINTC统一收集，再直接到达CPUINTC::
+
+ +-----+     +-----------------------+     +-------+
+ | IPI | --> |        CPUINTC        | <-- | Timer |
+ +-----+     +-----------------------+     +-------+
+              ^          ^          ^
+              |          |          |
+              |    +----------+     |
+       +---------+ | AVECINTC | +---------+     +-------+
+       | EIOINTC | +----------+ | LIOINTC | <-- | UARTs |
+       +---------+ | REDIRECT | +---------+     +-------+
+            ^      +----------+
+            |            ^
+            |            |
+       +---------+  +---------+
+       | PCH-PIC |  | PCH-MSI |
+       +---------+  +---------+
+         ^     ^           ^
+         |     |           |
+ +---------+ +---------+ +---------+
+ | Devices | | PCH-LPC | | Devices |
+ +---------+ +---------+ +---------+
+                  ^
+                  |
+             +---------+
+             | Devices |
+             +---------+
+
 ACPI相关的定义
 ==============