[PATCH v5 4/9] drivers: base cacheinfo: Add support for ACPI based firmware tables

[Jeremy Linton]

Add a entry to to struct cacheinfo to maintain a reference to the PPTT
node which can be used to match identical caches across cores. Also
stub out cache_setup_acpi() so that individual architectures can
enable ACPI topology parsing.

Signed-off-by: Jeremy Linton <jeremy.linton at arm.com>
---
 drivers/acpi/pptt.c       |  1 +
 drivers/base/cacheinfo.c  | 20 ++++++++++++++------
 include/linux/cacheinfo.h | 13 ++++++++++++-
 3 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
index 0f8a1631af33..a35e457cefb7 100644
--- a/drivers/acpi/pptt.c
+++ b/drivers/acpi/pptt.c
@@ -329,6 +329,7 @@ static void update_cache_properties(struct cacheinfo *this_leaf,
 {
 	int valid_flags = 0;
 
+	this_leaf->firmware_node = cpu_node;
 	if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID) {
 		this_leaf->size = found_cache->size;
 		valid_flags++;
diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index eb3af2739537..ba89f9310e6f 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -86,7 +86,10 @@ static int cache_setup_of_node(unsigned int cpu)
 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
 					   struct cacheinfo *sib_leaf)
 {
-	return sib_leaf->of_node == this_leaf->of_node;
+	if (acpi_disabled)
+		return sib_leaf->of_node == this_leaf->of_node;
+	else
+		return sib_leaf->firmware_node == this_leaf->firmware_node;
 }
 
 /* OF properties to query for a given cache type */
@@ -215,6 +218,11 @@ static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
 }
 #endif
 
+int __weak cache_setup_acpi(unsigned int cpu)
+{
+	return -ENOTSUPP;
+}
+
 static int cache_shared_cpu_map_setup(unsigned int cpu)
 {
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
@@ -225,11 +233,11 @@ static int cache_shared_cpu_map_setup(unsigned int cpu)
 	if (this_cpu_ci->cpu_map_populated)
 		return 0;
 
-	if (of_have_populated_dt())
+	if (!acpi_disabled)
+		ret = cache_setup_acpi(cpu);
+	else if (of_have_populated_dt())
 		ret = cache_setup_of_node(cpu);
-	else if (!acpi_disabled)
-		/* No cache property/hierarchy support yet in ACPI */
-		ret = -ENOTSUPP;
+
 	if (ret)
 		return ret;
 
@@ -286,7 +294,7 @@ static void cache_shared_cpu_map_remove(unsigned int cpu)
 
 static void cache_override_properties(unsigned int cpu)
 {
-	if (of_have_populated_dt())
+	if (acpi_disabled && of_have_populated_dt())
 		return cache_of_override_properties(cpu);
 }
 
diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h
index 3d9805297cda..7ebff157ae6c 100644
--- a/include/linux/cacheinfo.h
+++ b/include/linux/cacheinfo.h
@@ -37,6 +37,8 @@ enum cache_type {
  * @of_node: if devicetree is used, this represents either the cpu node in
  *	case there's no explicit cache node or the cache node itself in the
  *	device tree
+ * @firmware_node: When not using DT, this may contain pointers to other
+ *	firmware based values. Particularly ACPI/PPTT unique values.
  * @disable_sysfs: indicates whether this node is visible to the user via
  *	sysfs or not
  * @priv: pointer to any private data structure specific to particular
@@ -65,8 +67,8 @@ struct cacheinfo {
 #define CACHE_ALLOCATE_POLICY_MASK	\
 	(CACHE_READ_ALLOCATE | CACHE_WRITE_ALLOCATE)
 #define CACHE_ID		BIT(4)
-
 	struct device_node *of_node;
+	void *firmware_node;
 	bool disable_sysfs;
 	void *priv;
 };
@@ -99,6 +101,15 @@ int func(unsigned int cpu)					\
 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu);
 int init_cache_level(unsigned int cpu);
 int populate_cache_leaves(unsigned int cpu);
+int cache_setup_acpi(unsigned int cpu);
+int acpi_find_last_cache_level(unsigned int cpu);
+#ifndef CONFIG_ACPI
+int acpi_find_last_cache_level(unsigned int cpu)
+{
+	/*ACPI kernels should be built with PPTT support*/
+	return 0;
+}
+#endif
 
 const struct attribute_group *cache_get_priv_group(struct cacheinfo *this_leaf);
 
-- 
2.13.5