[Patch v7 17/18] x86, irq: Introduce helper to check whether an IOAPIC has been registered

Jiang Liu
2014-10-27T05:21:59Z

Introduce acpi_ioapic_registered() to check whether an IOAPIC has already
been registered, it will be used when enabling IOAPIC hotplug.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
arch/x86/include/asm/io_apic.h | 1 +
arch/x86/kernel/acpi/boot.c | 22 ++++++++++++++++++++++
arch/x86/kernel/apic/io_apic.c | 11 +++++++++++
include/linux/acpi.h | 1 +
4 files changed, 35 insertions(+)

diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h
index 7c04b8ec22a4..ca742d5249db 100644
--- a/arch/x86/include/asm/io_apic.h
+++ b/arch/x86/include/asm/io_apic.h
@@ -191,6 +191,7 @@ extern void mp_unmap_irq(int irq);
extern int mp_register_ioapic(int id, u32 address, u32 gsi_base,
struct ioapic_domain_cfg *cfg);
extern int mp_unregister_ioapic(u32 gsi_base);
+extern int mp_ioapic_registered(u32 gsi_base);
extern int mp_irqdomain_map(struct irq_domain *domain, unsigned int virq,
irq_hw_number_t hwirq);
extern void mp_irqdomain_unmap(struct irq_domain *domain, unsigned int virq);
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index bc61a5c0e7b6..f27b33194e06 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -825,6 +825,28 @@ int acpi_unregister_ioapic(acpi_handle handle, u32 gsi_base)
}
EXPORT_SYMBOL(acpi_unregister_ioapic);

+/**
+ * acpi_ioapic_registered - Check whether IOAPIC assoicatied with @gsi_base
+ * has been registered
+ * @handle: ACPI handle of the IOAPIC deivce
+ * @gsi_base: GSI base associated with the IOAPIC
+ *
+ * Assume caller holds some type of lock to serialize acpi_ioapic_registered()
+ * with acpi_register_ioapic()/acpi_unregister_ioapic().
+ */
+int acpi_ioapic_registered(acpi_handle handle, u32 gsi_base)
+{
+ int ret = 0;
+
+#ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
+ down_read(&acpi_ioapic_rwsem);
+ ret = mp_ioapic_registered(gsi_base);
+ up_read(&acpi_ioapic_rwsem);
+#endif
+
+ return ret;
+}
+
static int __init acpi_parse_sbf(struct acpi_table_header *table)
{
struct acpi_table_boot *sb;
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 9e5432ee2070..df3858de3031 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -4018,6 +4018,17 @@ int mp_unregister_ioapic(u32 gsi_base)
return 0;
}

+int mp_ioapic_registered(u32 gsi_base)
+{
+ int ioapic;
+
+ for_each_ioapic(ioapic)
+ if (ioapics[ioapic].gsi_config.gsi_base == gsi_base)
+ return 1;
+
+ return 0;
+}
+
int mp_irqdomain_map(struct irq_domain *domain, unsigned int virq,
irq_hw_number_t hwirq)
{
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 77cecd0350e7..be6be0f91337 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -152,6 +152,7 @@ int acpi_get_ioapic_id(acpi_handle handle, u32 gsi_base, u64 *phys_addr);

int acpi_register_ioapic(acpi_handle handle, u64 phys_addr, u32 gsi_base);
int acpi_unregister_ioapic(acpi_handle handle, u32 gsi_base);
+int acpi_ioapic_registered(acpi_handle handle, u32 gsi_base);
void acpi_irq_stats_init(void);
extern u32 acpi_irq_handled;
extern u32 acpi_irq_not_handled;
--
1.7.10.4