[PATCH 2/3] cacheinfo: Check cache properties are present in DT

Pierre Gondois
2023-03-27T12:01:44Z

If a Device Tree (DT) is used, the presence of cache properties is
assumed. Not finding any is not considered. For arm64 platforms,
cache information can be fetched from the clidr_el1 register.
Checking whether cache information is available in the DT
allows to switch to using clidr_el1.

init_of_cache_level()
\-of_count_cache_leaves()
will assume there a 2 cache leaves (L1 data/instruction caches), which
can be different from clidr_el1 information.

cache_setup_of_node() tries to read cache properties in the DT.
If there are none, this is considered a success. Knowing no
information was available would allow to switch to using clidr_el1.

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
---
drivers/base/cacheinfo.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index 4ca117574af1..5b0edf2d5da8 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -78,6 +78,9 @@ bool last_level_cache_is_shared(unsigned int cpu_x, unsigned int cpu_y)
}

#ifdef CONFIG_OF
+
+static bool of_check_cache_nodes(struct device_node *np);
+
/* OF properties to query for a given cache type */
struct cache_type_info {
const char *size_prop;
@@ -205,6 +208,11 @@ static int cache_setup_of_node(unsigned int cpu)
return -ENOENT;
}

+ if (!of_check_cache_nodes(np)) {
+ of_node_put(np);
+ return -ENOENT;
+ }
+
prev = np;

while (index < cache_leaves(cpu)) {
@@ -229,6 +237,25 @@ static int cache_setup_of_node(unsigned int cpu)
return 0;
}

+static bool of_check_cache_nodes(struct device_node *np)
+{
+ struct device_node *next;
+
+ if (of_property_read_bool(np, "cache-size") ||
+ of_property_read_bool(np, "i-cache-size") ||
+ of_property_read_bool(np, "d-cache-size") ||
+ of_property_read_bool(np, "cache-unified"))
+ return true;
+
+ next = of_find_next_cache_node(np);
+ if (next) {
+ of_node_put(next);
+ return true;
+ }
+
+ return false;
+}
+
static int of_count_cache_leaves(struct device_node *np)
{
unsigned int leaves = 0;
@@ -260,6 +287,9 @@ int init_of_cache_level(unsigned int cpu)
struct device_node *prev = NULL;
unsigned int levels = 0, leaves, level;

+ if (!of_check_cache_nodes(np))
+ goto err_out;
+
leaves = of_count_cache_leaves(np);
if (leaves > 0)
levels = 1;
--
2.25.1