[PATCH v10 2/8] of: Add helper for mapping device node to logical CPU number
From: Suzuki K Poulose <suzuki.poulose@arm.com>
Date: 2017-11-03 17:53:35
Also in:
linux-arm-kernel, lkml
Subsystem:
open firmware and flattened device tree, the rest · Maintainers:
Rob Herring, Saravana Kannan, Linus Torvalds
Add a helper to map a device node to a logical CPU number to avoid duplication. Currently this is open coded in different places (e.g gic-v3, coresight). The helper tries to map device node to a "possible" logical CPU id, which may not be online yet. It is the responsibility of the user to make sure that the CPU is online. The helper uses of_cpu_device_node_get() to retrieve the device node for a given CPU (which uses per_cpu data if available else falls back to slower of_get_cpu_node()). Cc: devicetree@vger.kernel.org Cc: Frank Rowand <redacted> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Sudeep Holla <redacted> Reviewed-by: Marc Zyngier <redacted> Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> --- Changes since V6: - Use faster of_cpu_device_node_get instead of of_get_cpu_node(), which now falls back to latter if called in early. Changes since V3: - Renamed the helper to of_cpu_node_to_id(), suggested by Rob - Return -ENODEV on failure than nr_cpus_id --- drivers/of/base.c | 26 ++++++++++++++++++++++++++ include/linux/of.h | 7 +++++++ 2 files changed, 33 insertions(+)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 63897531cd75..753c8160a092 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c@@ -418,6 +418,32 @@ struct device_node *of_get_cpu_node(int cpu, unsigned int *thread) EXPORT_SYMBOL(of_get_cpu_node); /** + * of_cpu_node_to_id: Get the logical CPU number for a given device_node + * + * @cpu_node: Pointer to the device_node for CPU. + * + * Returns the logical CPU number of the given CPU device_node. + * Returns -ENODEV if the CPU is not found. + */ +int of_cpu_node_to_id(struct device_node *cpu_node) +{ + int cpu; + bool found = false; + struct device_node *np; + + for_each_possible_cpu(cpu) { + np = of_cpu_device_node_get(cpu); + found = (cpu_node == np); + of_node_put(np); + if (found) + return cpu; + } + + return -ENODEV; +} +EXPORT_SYMBOL(of_cpu_node_to_id); + +/** * __of_device_is_compatible() - Check if the node matches given constraints * @device: pointer to node * @compat: required compatible string, NULL or "" for any match
diff --git a/include/linux/of.h b/include/linux/of.h
index b240ed69dc96..13eb8bc92c10 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h@@ -538,6 +538,8 @@ const char *of_prop_next_string(struct property *prop, const char *cur); bool of_console_check(struct device_node *dn, char *name, int index); +extern int of_cpu_node_to_id(struct device_node *np); + #else /* CONFIG_OF */ static inline void of_core_init(void)
@@ -872,6 +874,11 @@ static inline void of_property_clear_flag(struct property *p, unsigned long flag { } +static inline int of_cpu_node_to_id(struct device_node *np) +{ + return -ENODEV; +} + #define of_match_ptr(_ptr) NULL #define of_match_node(_matches, _node) NULL #endif /* CONFIG_OF */
--
2.13.6