ACPI: PPTT: Update acpi_find_last_cache_level() to acpi_get_cache_info()

acpi_find_last_cache_level() allows to find the last level of cache
for a given CPU. The function is only called on arm64 ACPI based
platforms to check for cache information that would be missing in
the CLIDR_EL1 register.
To allow populating (struct cpu_cacheinfo).num_leaves by only parsing
a PPTT, update acpi_find_last_cache_level() to get the 'split_levels',
i.e. the number of cache levels being split in data/instruction
caches.

It is assumed that there will not be data/instruction caches above a
unified cache.
If a split level consist of one data cache and no instruction cache
(or opposite), then the missing cache will still be populated
by default with minimal cache information, and maximal cpumask
(all non-existing caches have the same fw_token).

Suggested-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
Acked-by: Rafael J. Wysocki  <rafael.j.wysocki@intel.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230104183033.755668-6-pierre.gondois@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h
index ff0328f3fbb0..00d8e7f9d1c6 100644
--- a/include/linux/cacheinfo.h
+++ b/include/linux/cacheinfo.h
@@ -88,19 +88,22 @@ bool last_level_cache_is_shared(unsigned int cpu_x, unsigned int cpu_y);
 int detect_cache_attributes(unsigned int cpu);
 #ifndef CONFIG_ACPI_PPTT
 /*
- * acpi_find_last_cache_level is only called on ACPI enabled
+ * acpi_get_cache_info() is only called on ACPI enabled
  * platforms using the PPTT for topology. This means that if
  * the platform supports other firmware configuration methods
  * we need to stub out the call when ACPI is disabled.
  * ACPI enabled platforms not using PPTT won't be making calls
  * to this function so we need not worry about them.
  */
-static inline int acpi_find_last_cache_level(unsigned int cpu)
+static inline
+int acpi_get_cache_info(unsigned int cpu,
+			unsigned int *levels, unsigned int *split_levels)
 {
 	return 0;
 }
 #else
-int acpi_find_last_cache_level(unsigned int cpu);
+int acpi_get_cache_info(unsigned int cpu,
+			unsigned int *levels, unsigned int *split_levels);
 #endif
 
 const struct attribute_group *cache_get_priv_group(struct cacheinfo *this_leaf);