It is useful to have helper function just to get the number of cache
levels for a given logical cpu. This patch adds the support for the
same.
It will be used on ARM64 platform where the device tree provides the
information for the additional non-architected/transparent/external
last level caches that are not integrated with the processors.
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
---
drivers/of/base.c | 22 ++++++++++++++++++++++
include/linux/of.h | 1 +
2 files changed, 23 insertions(+)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index d4bea3c797d6..f7a2b47b3c77 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2268,6 +2268,28 @@ struct device_node *of_find_next_cache_node(const struct device_node *np)
}
/**
+ * of_count_cache_levels - Find the total number of cache levels for the
+ * given logical cpu
+ *
+ * @cpu: cpu number(logical index) for which cache levels is being counted
+ *
+ * Returns the total number of cache levels for the given logical cpu
+ */
+int of_count_cache_levels(unsigned int cpu)
+{
+ int level = 0;
+ struct device_node *np = of_cpu_device_node_get(cpu);
+
+ while (np) {
+ level++;
+ of_node_put(np);
+ np = of_find_next_cache_node(np);
+ }
+
+ return level;
+}
+
+/**
* of_graph_parse_endpoint() - parse common endpoint node properties
* @node: pointer to endpoint device_node
* @endpoint: pointer to the OF endpoint data structure
diff --git a/include/linux/of.h b/include/linux/of.h
index d72f01009297..c8597ae71ff3 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -280,6 +280,7 @@ extern struct device_node *of_get_child_by_name(const struct device_node *node,
/* cache lookup */
extern struct device_node *of_find_next_cache_node(const struct device_node *);
+extern int of_count_cache_levels(unsigned int cpu);
extern struct device_node *of_find_node_with_property(
struct device_node *from, const char *prop_name);
--
2.7.4
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