Commit-ID:  cf45268eceac09ff4af677f6e876b4d0397e1d3f
Gitweb:     http://git.kernel.org/tip/cf45268eceac09ff4af677f6e876b4d0397e1d3f
Author:     Jiang Liu <[email protected]>
AuthorDate: Mon, 27 Oct 2014 13:21:47 +0800
Committer:  Thomas Gleixner <[email protected]>
CommitDate: Mon, 3 Nov 2014 11:56:08 +0100

x86, irq: Introduce helper to check whether an IOAPIC has been registered

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 <[email protected]>
Acked-by: Pavel Machek <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Joerg Roedel <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Yinghai Lu <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Grant Likely <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Link: 
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
---
 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 7c04b8e..ca742d5 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 77107a9..1ae52e0 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -824,6 +824,28 @@ 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
+       mutex_lock(&acpi_ioapic_lock);
+       ret  = mp_ioapic_registered(gsi_base);
+       mutex_unlock(&acpi_ioapic_lock);
+#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 011ebca..ff2709e 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -4026,6 +4026,17 @@ 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 77cecd0..be6be0f 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;
--
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