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of: Add of_get_cpu_hwid() to read hardware ID from CPU nodes

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There are various open coded implementions parsing the CPU node 'reg'
property which contains the CPU's hardware ID. Introduce a new function,
of_get_cpu_hwid(), to read the hardware ID.

All the callers should be DT only code, so no need for an empty
function.

Cc: Frank Rowand <frowand.list@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20211006164332.1981454-2-robh@kernel.org
This commit is contained in:
Rob Herring 2021-10-06 11:43:21 -05:00
parent 378be0cca6
commit 795e92ec5f
2 changed files with 23 additions and 0 deletions
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22
drivers/of/base.c
View file

@ -286,6 +286,28 @@ const void *of_get_property(const struct device_node *np, const char *name,
}
EXPORT_SYMBOL(of_get_property);
/**
* of_get_cpu_hwid - Get the hardware ID from a CPU device node
*
* @cpun: CPU number(logical index) for which device node is required
* @thread: The local thread number to get the hardware ID for.
*
* Return: The hardware ID for the CPU node or ~0ULL if not found.
*/
u64 of_get_cpu_hwid(struct device_node *cpun, unsigned int thread)
{
const __be32 *cell;
int ac, len;
ac = of_n_addr_cells(cpun);
cell = of_get_property(cpun, "reg", &len);
if (!cell || !ac || ((sizeof(*cell) * ac * (thread + 1)) > len))
return ~0ULL;
cell += ac * thread;
return of_read_number(cell, ac);
}
/*
* arch_match_cpu_phys_id - Match the given logical CPU and physical id
*

1
include/linux/of.h
View file

@ -353,6 +353,7 @@ extern struct device_node *of_get_cpu_node(int cpu, unsigned int *thread);
extern struct device_node *of_get_next_cpu_node(struct device_node *prev);
extern struct device_node *of_get_cpu_state_node(struct device_node *cpu_node,
int index);
extern u64 of_get_cpu_hwid(struct device_node *cpun, unsigned int thread);
#define for_each_property_of_node(dn, pp) \
for (pp = dn->properties; pp != NULL; pp = pp->next)