[RFC PATCH v3 16/27] hw/loongarch: Add LoongArch cpu interrupt support(CPUINTC)

[Xiaojuan Yang <yangxiaojuan@loongson.cn>]

Loongson-3A5000 support 14 interrupts from 64 - 77(Timer->75 IPI->76)
Loongson-3A5000 and ls7a form a legacy model and extended model irq
hierarchy.Tcg mode emulate a simplified extended model which
has no Legacy I/O Interrupt Controller(LIOINTC) and LPC.
e.g:

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

The following series patch will realize the interrupt
controller in this model.

More detailed info can be found at the kernel doc or manual
1.https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/
linux-loongson.git/tree/Documentation/loongarch?h=loongarch-next
2.https://github.com/loongson/LoongArch-Documentation

Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>
---
 target/loongarch/cpu.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/target/loongarch/cpu.c b/target/loongarch/cpu.c
index 62c2a4d813..afa550c950 100644
--- a/target/loongarch/cpu.c
+++ b/target/loongarch/cpu.c
@@ -504,11 +504,39 @@ static void loongarch_cpu_realizefn(DeviceState *dev, Error **errp)
     lacc->parent_realize(dev, errp);
 }
 
+#ifndef CONFIG_USER_ONLY
+static void loongarch_cpu_set_irq(void *opaque, int irq, int level)
+{
+    LoongArchCPU *cpu = opaque;
+    CPULoongArchState *env = &cpu->env;
+    CPUState *cs = CPU(cpu);
+
+    if (irq < 0 || irq > N_IRQS) {
+        return;
+    }
+
+    if (level) {
+        env->CSR_ESTAT |= 1 << irq;
+    } else {
+        env->CSR_ESTAT &= ~(1 << irq);
+    }
+
+    if (FIELD_EX64(env->CSR_ESTAT, CSR_ESTAT, IS)) {
+        cpu_interrupt(cs, CPU_INTERRUPT_HARD);
+    } else {
+        cpu_reset_interrupt(cs, CPU_INTERRUPT_HARD);
+    }
+}
+#endif
+
 static void loongarch_cpu_initfn(Object *obj)
 {
     LoongArchCPU *cpu = LOONGARCH_CPU(obj);
 
     cpu_set_cpustate_pointers(cpu);
+#ifndef CONFIG_USER_ONLY
+    qdev_init_gpio_in(DEVICE(cpu), loongarch_cpu_set_irq, N_IRQS);
+#endif
 }
 
 static ObjectClass *loongarch_cpu_class_by_name(const char *cpu_model)
-- 
2.27.0