ACPI/PPTT: Add function to return ACPI 6.3 Identical tokens

ACPI 6.3 adds a flag to indicate that child nodes are all
identical cores. This is useful to authoritatively determine
if a set of (possibly offline) cores are identical or not.

Since the flag doesn't give us a unique id we can generate
one and use it to create bitmaps of sibling nodes, or simply
in a loop to determine if a subset of cores are identical.

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index d315d86844e4..5bcd23e5ccd6 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1303,6 +1303,7 @@ static inline int lpit_read_residency_count_address(u64 *address)
 #ifdef CONFIG_ACPI_PPTT
 int find_acpi_cpu_topology(unsigned int cpu, int level);
 int find_acpi_cpu_topology_package(unsigned int cpu);
+int find_acpi_cpu_topology_hetero_id(unsigned int cpu);
 int find_acpi_cpu_cache_topology(unsigned int cpu, int level);
 #else
 static inline int find_acpi_cpu_topology(unsigned int cpu, int level)
@@ -1313,6 +1314,10 @@ static inline int find_acpi_cpu_topology_package(unsigned int cpu)
 {
         return -EINVAL;
 }
+static inline int find_acpi_cpu_topology_hetero_id(unsigned int cpu)
+{
+        return -EINVAL;
+}
 static inline int find_acpi_cpu_cache_topology(unsigned int cpu, int level)
 {
         return -EINVAL;