[PATCH v1] ACPI / PPTT: Populate cache-id from rev3 of PPTT in ACPIv6.4

[Joey Gouly <joey.gouly@xxxxxxx>]

From: James Morse <james.morse@xxxxxxx>

ACPIv6.4 adds a 'cache id' to the PPTT Cache Type Structure.
Copy this property accross into the cacheinfo leaf when it was
provided by firmware.

This value getes exposed to userspace as:
/sys/devices/system/cpu/cpu*/cache/index*/id.
See the "Cache IDs" section of Documentation/x86/resctrl.rst.

Co-authored-by: Joey Gouly <joey.gouly@xxxxxxx>
Signed-off-by: James Morse <james.morse@xxxxxxx>
Signed-off-by: Joey Gouly <joey.gouly@xxxxxxx>
---
 drivers/acpi/pptt.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
index 4ae93350b70d..c18a30154db5 100644
--- a/drivers/acpi/pptt.c
+++ b/drivers/acpi/pptt.c
@@ -344,6 +344,7 @@ static struct acpi_pptt_cache *acpi_find_cache_node(struct acpi_table_header *ta
 
 /**
  * update_cache_properties() - Update cacheinfo for the given processor
+ * @table: The PPTT table - for testing the revision
  * @this_leaf: Kernel cache info structure being updated
  * @found_cache: The PPTT node describing this cache instance
  * @cpu_node: A unique reference to describe this cache instance
@@ -354,10 +355,13 @@ static struct acpi_pptt_cache *acpi_find_cache_node(struct acpi_table_header *ta
  *
  * Return: nothing. Side effect of updating the global cacheinfo
  */
-static void update_cache_properties(struct cacheinfo *this_leaf,
+static void update_cache_properties(struct acpi_table_header *table,
+				    struct cacheinfo *this_leaf,
 				    struct acpi_pptt_cache *found_cache,
 				    struct acpi_pptt_processor *cpu_node)
 {
+	struct acpi_pptt_cache_v1* found_cache_v1;
+
 	this_leaf->fw_token = cpu_node;
 	if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
 		this_leaf->size = found_cache->size;
@@ -405,6 +409,14 @@ static void update_cache_properties(struct cacheinfo *this_leaf,
 	if (this_leaf->type == CACHE_TYPE_NOCACHE &&
 	    found_cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)
 		this_leaf->type = CACHE_TYPE_UNIFIED;
+
+	if (table->revision >= 3 &&
+	    (found_cache->flags & ACPI_PPTT_CACHE_ID_VALID)) {
+		found_cache_v1 = ACPI_ADD_PTR(struct acpi_pptt_cache_v1,
+	                                      found_cache, sizeof(struct acpi_pptt_cache));
+		this_leaf->id = found_cache_v1->cache_id;
+		this_leaf->attributes |= CACHE_ID;
+	}
 }
 
 static void cache_setup_acpi_cpu(struct acpi_table_header *table,
@@ -425,7 +437,7 @@ static void cache_setup_acpi_cpu(struct acpi_table_header *table,
 						   &cpu_node);
 		pr_debug("found = %p %p\n", found_cache, cpu_node);
 		if (found_cache)
-			update_cache_properties(this_leaf,
+			update_cache_properties(table, this_leaf,
 						found_cache,
 						cpu_node);
 
-- 
2.17.1