linux-kernel - [PATCH] drivers: base: cacheinfo: support DT overrides for cache type

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Date:   Thu, 16 Nov 2017 20:58:09 +0800
From:   Tan Xiaojun <tanxiaojun@...wei.com>
To:     <gregkh@...uxfoundation.org>, <sudeep.holla@....com>
CC:     <linux-kernel@...r.kernel.org>
Subject: [PATCH] drivers: base: cacheinfo: support DT overrides for cache type

Since commit dfea747d2aba ("drivers: base: cacheinfo: support DT
overrides for cache properties"), we can set the correct cacheinfo
via DT. But the cache type can't be set in the same way.

I found this may be a problem in recent tests. I tested L3 cache
node setting in DT in Hisilicon D03/D05 board. And I got cacheinfo
via sysfs below:

$ cat /sys/devices/system/cpu/cpu*/cache/index3/
allocation_policy      level                  power/
shared_cpu_map         uevent                 write_policy
coherency_line_size    number_of_sets         shared_cpu_list
size                   ways_of_associativity

This is incomplete, no type file to display type info. Because L3
cache is uncore, we can't get correct type info from system
register, and will get a default type "CACHE_TYPE_NOCACHE". Then
use "lscpu" will print an error like below:

$ lscpu
lscpu: cannot open /sys/devices/system/cpu/cpu0/cache/index3/type:
No such file or directory

So I think maybe we can set correct cache type via DT too.

Signed-off-by: Tan Xiaojun <tanxiaojun@...wei.com>
---
 drivers/base/cacheinfo.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index eb3af27..3e650dc 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -122,6 +122,15 @@ static inline int get_cacheinfo_idx(enum cache_type type)
 	return type;
 }
 
+static void cache_type(struct cacheinfo *this_leaf)
+{
+	const __be32 *cache_type;
+
+	cache_type = of_get_property(this_leaf->of_node, "type", NULL);
+	if (cache_type)
+		this_leaf->type = of_read_number(cache_type, 1);
+}
+
 static void cache_size(struct cacheinfo *this_leaf)
 {
 	const char *propname;
@@ -194,6 +203,7 @@ static void cache_of_override_properties(unsigned int cpu)
 
 	for (index = 0; index < cache_leaves(cpu); index++) {
 		this_leaf = this_cpu_ci->info_list + index;
+		cache_type(this_leaf);
 		cache_size(this_leaf);
 		cache_get_line_size(this_leaf);
 		cache_nr_sets(this_leaf);
-- 
2.7.4