[PATCH 2/9] x86/apic: Add select() method on vector irqdomain

[David Woodhouse <dwmw2@xxxxxxxxxxxxx>]

From: David Woodhouse <dwmw@xxxxxxxxxxxx>

This will be used to select the irqdomain for I/OAPIC and HPET.

Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
---
 arch/x86/include/asm/irqdomain.h |  3 +++
 arch/x86/kernel/apic/vector.c    | 43 ++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/arch/x86/include/asm/irqdomain.h b/arch/x86/include/asm/irqdomain.h
index cd684d45cb5f..125c23b7bad3 100644
--- a/arch/x86/include/asm/irqdomain.h
+++ b/arch/x86/include/asm/irqdomain.h
@@ -12,6 +12,9 @@ enum {
 	X86_IRQ_ALLOC_LEGACY				= 0x2,
 };
 
+extern int x86_fwspec_is_ioapic(struct irq_fwspec *fwspec);
+extern int x86_fwspec_is_hpet(struct irq_fwspec *fwspec);
+
 extern struct irq_domain *x86_vector_domain;
 
 extern void init_irq_alloc_info(struct irq_alloc_info *info,
diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index bb2e2a2488a5..b9b05caa28a4 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -636,7 +636,50 @@ static void x86_vector_debug_show(struct seq_file *m, struct irq_domain *d,
 }
 #endif
 
+int x86_fwspec_is_ioapic(struct irq_fwspec *fwspec)
+{
+	if (fwspec->param_count != 1)
+		return 0;
+
+	if (is_fwnode_irqchip(fwspec->fwnode)) {
+		const char *fwname = fwnode_get_name(fwspec->fwnode);
+		return fwname && !strncmp(fwname, "IO-APIC-", 8) &&
+			simple_strtol(fwname+8, NULL, 10) == fwspec->param[0];
+	}
+	return to_of_node(fwspec->fwnode) &&
+		of_device_is_compatible(to_of_node(fwspec->fwnode),
+					"intel,ce4100-ioapic");
+}
+
+int x86_fwspec_is_hpet(struct irq_fwspec *fwspec)
+{
+	if (fwspec->param_count != 1)
+		return 0;
+
+	if (is_fwnode_irqchip(fwspec->fwnode)) {
+		const char *fwname = fwnode_get_name(fwspec->fwnode);
+		return fwname && !strncmp(fwname, "HPET-MSI-", 9) &&
+			simple_strtol(fwname+9, NULL, 10) == fwspec->param[0];
+	}
+	return 0;
+}
+
+static int x86_vector_select(struct irq_domain *d, struct irq_fwspec *fwspec,
+			     enum irq_domain_bus_token bus_token)
+{
+	/*
+	 * HPET and I/OAPIC cannot be parented in the vector domain
+	 * if IRQ remapping is enabled. APIC IDs above 15 bits are
+	 * only permitted if IRQ remapping is enabled, so check that.
+	 */
+	if (apic->apic_id_valid(32768))
+		return 0;
+
+	return x86_fwspec_is_ioapic(fwspec) || x86_fwspec_is_hpet(fwspec);
+}
+
 static const struct irq_domain_ops x86_vector_domain_ops = {
+	.select		= x86_vector_select,
 	.alloc		= x86_vector_alloc_irqs,
 	.free		= x86_vector_free_irqs,
 	.activate	= x86_vector_activate,
-- 
2.26.2