[PATCH v2 7/8] of: base: add support to get the device node for the CPU's last level cache
From: Sudeep Holla <hidden>
Date: 2022-05-18 09:34:40
Also in:
linux-riscv, lkml
Subsystem:
open firmware and flattened device tree, the rest · Maintainers:
Rob Herring, Saravana Kannan, Linus Torvalds
It is useful to have helper function just to get the pointer to the device node of the last level cache for a given logical cpu. It can be used as unique firmware identifier for the last level cache. This is useful to obtain the cpumask/cpumap of all the CPUs sharing the last level cache using the device node pointer as unique identifier for the last level cache. Cc: Rob Herring <robh+dt@kernel.org> Signed-off-by: Sudeep Holla <redacted> --- drivers/of/base.c | 33 +++++++++++++++++++++++++-------- include/linux/of.h | 1 + 2 files changed, 26 insertions(+), 8 deletions(-)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index d4f98c8469ed..0b6a8c3f9a85 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c@@ -2072,17 +2072,17 @@ struct device_node *of_find_next_cache_node(const struct device_node *np) } /** - * of_find_last_cache_level - Find the level at which the last cache is - * present for the given logical cpu + * of_find_last_level_cache_node - Find the device node at which the last + * cache is present for the given logical cpu * - * @cpu: cpu number(logical index) for which the last cache level is needed + * @cpu: cpu number(logical index) for which the last cache level's device + * node is needed * - * Return: The the level at which the last cache is present. It is exactly - * same as the total number of cache levels for the given logical cpu. + * Return: The device node corresponding to the last cache for the given + * logical cpu */ -int of_find_last_cache_level(unsigned int cpu) +struct device_node *of_find_last_level_cache_node(unsigned int cpu) { - u32 cache_level = 0; struct device_node *prev = NULL, *np = of_cpu_device_node_get(cpu); while (np) {
@@ -2091,7 +2091,24 @@ int of_find_last_cache_level(unsigned int cpu) np = of_find_next_cache_node(np); } - of_property_read_u32(prev, "cache-level", &cache_level); + return prev; +} + +/** + * of_find_last_cache_level - Find the level at which the last cache is + * present for the given logical cpu + * + * @cpu: cpu number(logical index) for which the last cache level is needed + * + * Return: The level at which the last cache is present. It is exactly + * same as the total number of cache levels for the given logical cpu. + */ +int of_find_last_cache_level(unsigned int cpu) +{ + u32 cache_level = 0; + struct device_node *np = of_find_last_level_cache_node(cpu); + + of_property_read_u32(np, "cache-level", &cache_level); return cache_level; }
diff --git a/include/linux/of.h b/include/linux/of.h
index 04971e85fbc9..ca0384cf08a3 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h@@ -297,6 +297,7 @@ 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 struct device_node *of_find_last_level_cache_node(unsigned int cpu); extern int of_find_last_cache_level(unsigned int cpu); extern struct device_node *of_find_node_with_property( struct device_node *from, const char *prop_name);
--
2.36.1
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