irqchip/loongarch-avec: Add AVEC irqchip support

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 |
              +---------+

Co-developed-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Co-developed-by: Liupu Wang <wangliupu@loongson.cn>
Signed-off-by: Liupu Wang <wangliupu@loongson.cn>
Co-developed-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Tianyang Zhang <zhangtianyang@loongson.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240823104337.25577-2-zhangtianyang@loongson.cn

2 files changed, 11 insertions, 0 deletions

diff --git a/arch/loongarch/kernel/paravirt.c b/arch/loongarch/kernel/paravirt.c
index 9c9b75b76f62..4d736a4e488d 100644
--- a/arch/loongarch/kernel/paravirt.c
+++ b/arch/loongarch/kernel/paravirt.c
@@ -134,6 +134,11 @@ static irqreturn_t pv_ipi_interrupt(int irq, void *dev)
 		info->ipi_irqs[IPI_IRQ_WORK]++;
 	}
 
+	if (action & SMP_CLEAR_VECTOR) {
+		complete_irq_moving();
+		info->ipi_irqs[IPI_CLEAR_VECTOR]++;
+	}
+
 	return IRQ_HANDLED;
 }
 
diff --git a/arch/loongarch/kernel/smp.c b/arch/loongarch/kernel/smp.c
index ca405ab86aae..4adbbef3450a 100644
--- a/arch/loongarch/kernel/smp.c
+++ b/arch/loongarch/kernel/smp.c
@@ -72,6 +72,7 @@ static const char *ipi_types[NR_IPI] __tracepoint_string = {
 	[IPI_RESCHEDULE] = "Rescheduling interrupts",
 	[IPI_CALL_FUNCTION] = "Function call interrupts",
 	[IPI_IRQ_WORK] = "IRQ work interrupts",
+	[IPI_CLEAR_VECTOR] = "Clear vector interrupts",
 };
 
 void show_ipi_list(struct seq_file *p, int prec)
@@ -248,6 +249,11 @@ static irqreturn_t loongson_ipi_interrupt(int irq, void *dev)
 		per_cpu(irq_stat, cpu).ipi_irqs[IPI_IRQ_WORK]++;
 	}
 
+	if (action & SMP_CLEAR_VECTOR) {
+		complete_irq_moving();
+		per_cpu(irq_stat, cpu).ipi_irqs[IPI_CLEAR_VECTOR]++;
+	}
+
 	return IRQ_HANDLED;
 }