A lot of code could be shared between the current ACPI init flow with
the possible OF init flow.

Extract it to a dedicated function.

The re-ordering of parent interrupt acquisition requires the
architecture code to reserve legacy interrupts from the dynamic
allocation by overriding arch_dynirq_lower_bound(), otherwise the parent
of LPC irqchip will be allocated to the intended static range of LPC
interrupts, which leads to allocation failure of LPC interrupts.

Co-developed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Icenowy Zheng <zhengxingda@iscas.ac.cn>
Tested-by: Yao Zi <me@ziyao.cc>
---
 drivers/irqchip/irq-loongson-pch-lpc.c | 52 ++++++++++++++++----------
 1 file changed, 32 insertions(+), 20 deletions(-)

diff --git a/drivers/irqchip/irq-loongson-pch-lpc.c b/drivers/irqchip/irq-loongson-pch-lpc.c
index 3ad46ec94e3c0..38d05135d2a7c 100644
--- a/drivers/irqchip/irq-loongson-pch-lpc.c
+++ b/drivers/irqchip/irq-loongson-pch-lpc.c
@@ -175,13 +175,10 @@ static struct syscore pch_lpc_syscore = {
 	.ops = &pch_lpc_syscore_ops,
 };
 
-int __init pch_lpc_acpi_init(struct irq_domain *parent,
-					struct acpi_madt_lpc_pic *acpi_pchlpc)
+static int __init pch_lpc_init(phys_addr_t addr, unsigned long size,
+			       struct fwnode_handle *irq_handle, int parent_irq)
 {
-	int parent_irq;
 	struct pch_lpc *priv;
-	struct irq_fwspec fwspec;
-	struct fwnode_handle *irq_handle;
 
 	priv = kzalloc_obj(*priv);
 	if (!priv)
@@ -189,7 +186,7 @@ int __init pch_lpc_acpi_init(struct irq_domain *parent,
 
 	raw_spin_lock_init(&priv->lpc_lock);
 
-	priv->base = ioremap(acpi_pchlpc->address, acpi_pchlpc->size);
+	priv->base = ioremap(addr, size);
 	if (!priv->base)
 		goto free_priv;
 
@@ -198,12 +195,6 @@ int __init pch_lpc_acpi_init(struct irq_domain *parent,
 		goto iounmap_base;
 	}
 
-	irq_handle = irq_domain_alloc_named_fwnode("lpcintc");
-	if (!irq_handle) {
-		pr_err("Unable to allocate domain handle\n");
-		goto iounmap_base;
-	}
-
 	/*
 	 * The LPC interrupt controller is a legacy i8259-compatible device,
 	 * which requires a static 1:1 mapping for IRQs 0-15.
@@ -213,15 +204,10 @@ int __init pch_lpc_acpi_init(struct irq_domain *parent,
 						    &pch_lpc_domain_ops, priv);
 	if (!priv->lpc_domain) {
 		pr_err("Failed to create IRQ domain\n");
-		goto free_irq_handle;
+		goto iounmap_base;
 	}
 	pch_lpc_reset(priv);
 
-	fwspec.fwnode = parent->fwnode;
-	fwspec.param[0] = acpi_pchlpc->cascade + GSI_MIN_PCH_IRQ;
-	fwspec.param[1] = IRQ_TYPE_LEVEL_HIGH;
-	fwspec.param_count = 2;
-	parent_irq = irq_create_fwspec_mapping(&fwspec);
 	irq_set_chained_handler_and_data(parent_irq, lpc_irq_dispatch, priv);
 
 	pch_lpc_priv = priv;
@@ -230,8 +216,6 @@ int __init pch_lpc_acpi_init(struct irq_domain *parent,
 
 	return 0;
 
-free_irq_handle:
-	irq_domain_free_fwnode(irq_handle);
 iounmap_base:
 	iounmap(priv->base);
 free_priv:
@@ -239,3 +223,31 @@ int __init pch_lpc_acpi_init(struct irq_domain *parent,
 
 	return -ENOMEM;
 }
+
+int __init pch_lpc_acpi_init(struct irq_domain *parent, struct acpi_madt_lpc_pic *acpi_pchlpc)
+{
+	struct fwnode_handle *irq_handle;
+	struct irq_fwspec fwspec;
+	int parent_irq, ret;
+
+	irq_handle = irq_domain_alloc_named_fwnode("lpcintc");
+	if (!irq_handle) {
+		pr_err("Unable to allocate domain handle\n");
+		return -ENOMEM;
+	}
+
+	fwspec.fwnode = parent->fwnode;
+	fwspec.param[0] = acpi_pchlpc->cascade + GSI_MIN_PCH_IRQ;
+	fwspec.param[1] = IRQ_TYPE_LEVEL_HIGH;
+	fwspec.param_count = 2;
+	parent_irq = irq_create_fwspec_mapping(&fwspec);
+
+	ret = pch_lpc_init(acpi_pchlpc->address, acpi_pchlpc->size,
+			   irq_handle, parent_irq);
+	if (ret) {
+		irq_domain_free_fwnode(irq_handle);
+		return ret;
+	}
+
+	return 0;
+}
-- 
2.52.0

On Sun, Mar 15 2026 at 00:28, Icenowy Zheng wrote:

> A lot of code could be shared between the current ACPI init flow with

s/could/can/    s/current/existing/

> the possible OF init flow.

s/possible/upcoming/

> Extract it to a dedicated function.

s/to/into/

> +
> +int __init pch_lpc_acpi_init(struct irq_domain *parent, struct acpi_madt_lpc_pic *acpi_pchlpc)
> +{
> +	struct fwnode_handle *irq_handle;
> +	struct irq_fwspec fwspec;
> +	int parent_irq, ret;
> +
> +	irq_handle = irq_domain_alloc_named_fwnode("lpcintc");
> +	if (!irq_handle) {
> +		pr_err("Unable to allocate domain handle\n");
> +		return -ENOMEM;
> +	}
> +
> +	fwspec.fwnode = parent->fwnode;
> +	fwspec.param[0] = acpi_pchlpc->cascade + GSI_MIN_PCH_IRQ;
> +	fwspec.param[1] = IRQ_TYPE_LEVEL_HIGH;
> +	fwspec.param_count = 2;
> +	parent_irq = irq_create_fwspec_mapping(&fwspec);
> +
> +	ret = pch_lpc_init(acpi_pchlpc->address, acpi_pchlpc->size,
> +			   irq_handle, parent_irq);

No line break required. You have 100 characters per line.

Thanks,

        tglx