[PATCH] irqchip/loongson-eiointc: Use early_cpu_to_node() instead of cpu_to_node()

[Huacai Chen <chenhuacai@xxxxxxxxxx>]

Multi-bridge machines required that all eiointc controllers in the system
are initialized, otherwise the system does not boot.

The initialization happens on the boot CPU during early boot and relies on
cpu_to_node() for identifying the individual nodes.

That works when the number of possible CPUs is large enough, but with a
command line limit, e.g. "nr_cpus=$N" for kdump, but fails when the CPUs
of the secondary nodes are not covered.

During early ACPI enumeration all CPU to node mappings are recorded up to
CONFIG_NR_CPUS. These are accessible via early_cpu_to_node() even in the
case that "nr_cpus=N" truncates the number of possible CPUs and only
provides the possible CPUs via cpu_to_node() translation.

Change the node lookup in the driver to use early_cpu_to_node() so that
even with a limitation on the number of possible CPUs all eointc instances
are initialized.

This can't obviously cure the case where CONFIG_NR_CPUS is too small.

[ tglx: Massaged changelog ]

Fixes: 64cc451e45e1 ("irqchip/loongson-eiointc: Fix incorrect use of acpi_get_vec_parent")
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20240623034113.1808727-1-chenhuacai@xxxxxxxxxxx

diff --git a/drivers/irqchip/irq-loongson-eiointc.c b/drivers/irqchip/irq-loongson-eiointc.c
index c7ddebf312ad..b1f2080be2be 100644
--- a/drivers/irqchip/irq-loongson-eiointc.c
+++ b/drivers/irqchip/irq-loongson-eiointc.c
@@ -15,6 +15,7 @@
 #include <linux/irqchip/chained_irq.h>
 #include <linux/kernel.h>
 #include <linux/syscore_ops.h>
+#include <asm/numa.h>
 
 #define EIOINTC_REG_NODEMAP	0x14a0
 #define EIOINTC_REG_IPMAP	0x14c0
@@ -339,7 +340,7 @@ static int __init pch_msi_parse_madt(union acpi_subtable_headers *header,
 	int node;
 
 	if (cpu_has_flatmode)
-		node = cpu_to_node(eiointc_priv[nr_pics - 1]->node * CORES_PER_EIO_NODE);
+		node = early_cpu_to_node(eiointc_priv[nr_pics - 1]->node * CORES_PER_EIO_NODE);
 	else
 		node = eiointc_priv[nr_pics - 1]->node;
 
@@ -431,7 +432,7 @@ int __init eiointc_acpi_init(struct irq_domain *parent,
 		goto out_free_handle;
 
 	if (cpu_has_flatmode)
-		node = cpu_to_node(acpi_eiointc->node * CORES_PER_EIO_NODE);
+		node = early_cpu_to_node(acpi_eiointc->node * CORES_PER_EIO_NODE);
 	else
 		node = acpi_eiointc->node;
 	acpi_set_vec_parent(node, priv->eiointc_domain, pch_group);