Commit 795e92ec authored by Rob Herring's avatar Rob Herring
Browse files

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



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: default avatarRob Herring <robh@kernel.org>
Tested-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: default avatarSudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20211006164332.1981454-2-robh@kernel.org
parent 378be0cc

drivers/of/base.c

+22 −0
Original line number Diff line number Diff line
@@ -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

 *

include/linux/of.h

+1 −0
Original line number Diff line number Diff line
@@ -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)