[PATCH V14 14/15] irqchip / ACPI: Introduce ACPI_IRQ_MODEL_LPIC for LoongArch

[Jianmin Lv <lvjianmin@loongson.cn>]

For LoongArch, ACPI_IRQ_MODEL_LPIC is introduced, and then the
callback acpi_get_gsi_domain_id and acpi_gsi_to_irq_fallback are
implemented.

The acpi_get_gsi_domain_id callback returns related fwnode handle
of irqdomain for different GSI range.

The acpi_gsi_to_irq_fallback will create new mapping for gsi when
the mapping of it is not found.

Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
---
 drivers/acpi/bus.c                  |  3 +++
 drivers/irqchip/irq-loongarch-cpu.c | 37 +++++++++++++++++++++++++++++++++++++
 include/linux/acpi.h                |  1 +
 3 files changed, 41 insertions(+)

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 86fa61a..63fbf00 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -1145,6 +1145,9 @@ static int __init acpi_bus_init_irq(void)
 	case ACPI_IRQ_MODEL_PLATFORM:
 		message = "platform specific model";
 		break;
+	case ACPI_IRQ_MODEL_LPIC:
+		message = "LPIC";
+		break;
 	default:
 		pr_info("Unknown interrupt routing model\n");
 		return -ENODEV;
diff --git a/drivers/irqchip/irq-loongarch-cpu.c b/drivers/irqchip/irq-loongarch-cpu.c
index c2f7411..1b241d7 100644
--- a/drivers/irqchip/irq-loongarch-cpu.c
+++ b/drivers/irqchip/irq-loongarch-cpu.c
@@ -15,6 +15,41 @@
 
 static struct irq_domain *irq_domain;
 
+static int lpic_gsi_to_irq(u32 gsi)
+{
+	/* Only pch irqdomain transferring is required for LoongArch. */
+	if (gsi >= GSI_MIN_PCH_IRQ && gsi <= GSI_MAX_PCH_IRQ)
+		return acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_HIGH);
+	return -1;
+}
+
+static struct fwnode_handle *lpic_get_gsi_domain_id(u32 gsi)
+{
+	int id;
+	struct fwnode_handle *domain_handle = NULL;
+
+	switch (gsi) {
+	case GSI_MIN_CPU_IRQ ... GSI_MAX_CPU_IRQ:
+		if (liointc_handle)
+			domain_handle = liointc_handle;
+		break;
+
+	case GSI_MIN_LPC_IRQ ... GSI_MAX_LPC_IRQ:
+		if (pch_lpc_handle)
+			domain_handle = pch_lpc_handle;
+		break;
+
+	case GSI_MIN_PCH_IRQ ... GSI_MAX_PCH_IRQ:
+		id = find_pch_pic(gsi);
+		if (id >= 0 && pch_pic_handle[id])
+			domain_handle = pch_pic_handle[id];
+
+		break;
+	}
+
+	return domain_handle;
+}
+
 static void mask_loongarch_irq(struct irq_data *d)
 {
 	clear_csr_ecfg(ECFGF(d->hwirq));
@@ -87,6 +122,8 @@ static int __init loongarch_cpu_irq_init(void)
 		panic("Failed to add irqdomain for LoongArch CPU");
 
 	set_handle_irq(&handle_cpu_irq);
+	acpi_set_irq_model(ACPI_IRQ_MODEL_LPIC, lpic_get_gsi_domain_id);
+	acpi_set_gsi_to_irq_fallback(lpic_gsi_to_irq);
 
 	return 0;
 }
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 71d3719..1bec0a3 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -105,6 +105,7 @@ enum acpi_irq_model_id {
 	ACPI_IRQ_MODEL_IOSAPIC,
 	ACPI_IRQ_MODEL_PLATFORM,
 	ACPI_IRQ_MODEL_GIC,
+	ACPI_IRQ_MODEL_LPIC,
 	ACPI_IRQ_MODEL_COUNT
 };
 
-- 
1.8.3.1