[Patch v4 22/23] ACPI: Add interfaces to parse IOAPIC ID for IOAPIC hotplug

Jiang Liu
2015-02-05T05:44:12Z

From: Yinghai Lu <yinghai@kernel.org>

We need to parse APIC ID for IOAPIC registration for IOAPIC hotplug.
ACPI _MAT method and MADT table are used to figure out IOAPIC ID, just
like parsing CPU APIC ID for CPU hotplug.

[ tglx: Fixed docbook comment ]

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/1414387308-27148-8-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
drivers/acpi/processor_core.c | 123 ++++++++++++++++++++++++++++++++++++++---
include/linux/acpi.h | 4 ++
2 files changed, 118 insertions(+), 9 deletions(-)

diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index 02e48394276c..7962651cdbd4 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -4,6 +4,10 @@
*
* Alex Chiang <achiang@hp.com>
* - Unified x86/ia64 implementations
+ *
+ * I/O APIC hotplug support
+ * Yinghai Lu <yinghai@kernel.org>
+ * Jiang Liu <jiang.liu@intel.com>
*/
#include <linux/export.h>
#include <linux/acpi.h>
@@ -12,6 +16,21 @@
#define _COMPONENT ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_core");

+static struct acpi_table_madt *get_madt_table(void)
+{
+ static struct acpi_table_madt *madt;
+ static int read_madt;
+
+ if (!read_madt) {
+ if (ACPI_FAILURE(acpi_get_table(ACPI_SIG_MADT, 0,
+ (struct acpi_table_header **)&madt)))
+ madt = NULL;
+ read_madt++;
+ }
+
+ return madt;
+}
+
static int map_lapic_id(struct acpi_subtable_header *entry,
u32 acpi_id, int *apic_id)
{
@@ -67,17 +86,10 @@ static int map_lsapic_id(struct acpi_subtable_header *entry,
static int map_madt_entry(int type, u32 acpi_id)
{
unsigned long madt_end, entry;
- static struct acpi_table_madt *madt;
- static int read_madt;
int phys_id = -1; /* CPU hardware ID */
+ struct acpi_table_madt *madt;

- if (!read_madt) {
- if (ACPI_FAILURE(acpi_get_table(ACPI_SIG_MADT, 0,
- (struct acpi_table_header **)&madt)))
- madt = NULL;
- read_madt++;
- }
-
+ madt = get_madt_table();
if (!madt)
return phys_id;

@@ -203,3 +215,96 @@ int acpi_get_cpuid(acpi_handle handle, int type, u32 acpi_id)
return acpi_map_cpuid(phys_id, acpi_id);
}
EXPORT_SYMBOL_GPL(acpi_get_cpuid);
+
+#ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
+static int get_ioapic_id(struct acpi_subtable_header *entry, u32 gsi_base,
+ u64 *phys_addr, int *ioapic_id)
+{
+ struct acpi_madt_io_apic *ioapic = (struct acpi_madt_io_apic *)entry;
+
+ if (ioapic->global_irq_base != gsi_base)
+ return 0;
+
+ *phys_addr = ioapic->address;
+ *ioapic_id = ioapic->id;
+ return 1;
+}
+
+static int parse_madt_ioapic_entry(u32 gsi_base, u64 *phys_addr)
+{
+ struct acpi_subtable_header *hdr;
+ unsigned long madt_end, entry;
+ struct acpi_table_madt *madt;
+ int apic_id = -1;
+
+ madt = get_madt_table();
+ if (!madt)
+ return apic_id;
+
+ entry = (unsigned long)madt;
+ madt_end = entry + madt->header.length;
+
+ /* Parse all entries looking for a match. */
+ entry += sizeof(struct acpi_table_madt);
+ while (entry + sizeof(struct acpi_subtable_header) < madt_end) {
+ hdr = (struct acpi_subtable_header *)entry;
+ if (hdr->type == ACPI_MADT_TYPE_IO_APIC &&
+ get_ioapic_id(hdr, gsi_base, phys_addr, &apic_id))
+ break;
+ else
+ entry += hdr->length;
+ }
+
+ return apic_id;
+}
+
+static int parse_mat_ioapic_entry(acpi_handle handle, u32 gsi_base,
+ u64 *phys_addr)
+{
+ struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+ struct acpi_subtable_header *header;
+ union acpi_object *obj;
+ int apic_id = -1;
+
+ if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer)))
+ goto exit;
+
+ if (!buffer.length || !buffer.pointer)
+ goto exit;
+
+ obj = buffer.pointer;
+ if (obj->type != ACPI_TYPE_BUFFER ||
+ obj->buffer.length < sizeof(struct acpi_subtable_header))
+ goto exit;
+
+ header = (struct acpi_subtable_header *)obj->buffer.pointer;
+ if (header->type == ACPI_MADT_TYPE_IO_APIC)
+ get_ioapic_id(header, gsi_base, phys_addr, &apic_id);
+
+exit:
+ kfree(buffer.pointer);
+ return apic_id;
+}
+
+/**
+ * acpi_get_ioapic_id - Get IOAPIC ID and physical address matching @gsi_base
+ * @handle: ACPI object for IOAPIC device
+ * @gsi_base: GSI base to match with
+ * @phys_addr: Pointer to store physical address of matching IOAPIC record
+ *
+ * Walk resources returned by ACPI_MAT method, then ACPI MADT table, to search
+ * for an ACPI IOAPIC record matching @gsi_base.
+ * Return IOAPIC id and store physical address in @phys_addr if found a match,
+ * otherwise return <0.
+ */
+int acpi_get_ioapic_id(acpi_handle handle, u32 gsi_base, u64 *phys_addr)
+{
+ int apic_id;
+
+ apic_id = parse_mat_ioapic_entry(handle, gsi_base, phys_addr);
+ if (apic_id == -1)
+ apic_id = parse_madt_ioapic_entry(gsi_base, phys_addr);
+
+ return apic_id;
+}
+#endif /* CONFIG_ACPI_HOTPLUG_IOAPIC */
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index e53822148b6a..24c7aa8b1d20 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -152,6 +152,10 @@ int acpi_map_cpu(acpi_handle handle, int physid, int *pcpu);
int acpi_unmap_cpu(int cpu);
#endif /* CONFIG_ACPI_HOTPLUG_CPU */

+#ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
+int acpi_get_ioapic_id(acpi_handle handle, u32 gsi_base, u64 *phys_addr);
+#endif
+
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);
--
1.7.10.4