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of: Add helper for mapping device node to logical CPU number 

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 <frowand.list@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
hifive-unleashed-5.1
Suzuki K Poulose 2018-01-02 11:25:27 +00:00 committed by Will Deacon
parent 82975c46da
commit a0e71cd9b1
2 changed files with 33 additions and 0 deletions
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26
drivers/of/base.c
View File

@ -315,6 +315,32 @@ 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

7
include/linux/of.h
View File

@ -544,6 +544,8 @@ 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)
@ -916,6 +918,11 @@ 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 */