ACPI / processor: Add acpi_map_madt_entry()

Follow-on arm64 ACPI/NUMA patches need to map MADT entries very early
(before kmalloc is usable).

Add acpi_map_madt_entry() which, indirectly, uses
early_memremap()/early_memunmap() to access the table and parse out
the mpidr.  The existing implementation of map_madt_entry() is
modified to take a pointer to the MADT as a parameter and the callers
adjusted.
Signed-off-by: David Daney <david.daney@cavium.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/processor_core.c

@@ -108,13 +108,12 @@ static int map_gicc_mpidr(struct acpi_subtable_header *entry,
 	return -EINVAL;
 }
 
-static phys_cpuid_t map_madt_entry(int type, u32 acpi_id)
+static phys_cpuid_t map_madt_entry(struct acpi_table_madt *madt,
+				   int type, u32 acpi_id)
 {
 	unsigned long madt_end, entry;
 	phys_cpuid_t phys_id = PHYS_CPUID_INVALID;	/* CPU hardware ID */
-	struct acpi_table_madt *madt;
 
-	madt = get_madt_table();
 	if (!madt)
 		return phys_id;
 
@@ -145,6 +144,25 @@ static phys_cpuid_t map_madt_entry(int type, u32 acpi_id)
 	return phys_id;
 }
 
+phys_cpuid_t __init acpi_map_madt_entry(u32 acpi_id)
+{
+	struct acpi_table_madt *madt = NULL;
+	acpi_size tbl_size;
+	phys_cpuid_t rv;
+
+	acpi_get_table_with_size(ACPI_SIG_MADT, 0,
+				 (struct acpi_table_header **)&madt,
+				 &tbl_size);
+	if (!madt)
+		return PHYS_CPUID_INVALID;
+
+	rv = map_madt_entry(madt, 1, acpi_id);
+
+	early_acpi_os_unmap_memory(madt, tbl_size);
+
+	return rv;
+}
+
 static phys_cpuid_t map_mat_entry(acpi_handle handle, int type, u32 acpi_id)
 {
 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
@@ -185,7 +203,7 @@ phys_cpuid_t acpi_get_phys_id(acpi_handle handle, int type, u32 acpi_id)
 
 	phys_id = map_mat_entry(handle, type, acpi_id);
 	if (invalid_phys_cpuid(phys_id))
-		phys_id = map_madt_entry(type, acpi_id);
+		phys_id = map_madt_entry(get_madt_table(), type, acpi_id);
 
 	return phys_id;
 }

include/acpi/processor.h

@@ -309,6 +309,7 @@ static inline int acpi_processor_get_bios_limit(int cpu, unsigned int *limit)
 
 /* in processor_core.c */
 phys_cpuid_t acpi_get_phys_id(acpi_handle, int type, u32 acpi_id);
+phys_cpuid_t acpi_map_madt_entry(u32 acpi_id);
 int acpi_map_cpuid(phys_cpuid_t phys_id, u32 acpi_id);
 int acpi_get_cpuid(acpi_handle, int type, u32 acpi_id);