linux/drivers/of/cpu.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/cpu.h>
#include <linux/kernel.h>
#include <linux/of.h>

/**
 * 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)
{ … }

/*
 * arch_match_cpu_phys_id - Match the given logical CPU and physical id
 *
 * @cpu: logical cpu index of a core/thread
 * @phys_id: physical identifier of a core/thread
 *
 * CPU logical to physical index mapping is architecture specific.
 * However this __weak function provides a default match of physical
 * id to logical cpu index. phys_id provided here is usually values read
 * from the device tree which must match the hardware internal registers.
 *
 * Returns true if the physical identifier and the logical cpu index
 * correspond to the same core/thread, false otherwise.
 */
bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id)
{ … }

/*
 * Checks if the given "prop_name" property holds the physical id of the
 * core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not
 * NULL, local thread number within the core is returned in it.
 */
static bool __of_find_n_match_cpu_property(struct device_node *cpun,
			const char *prop_name, int cpu, unsigned int *thread)
{ … }

/*
 * arch_find_n_match_cpu_physical_id - See if the given device node is
 * for the cpu corresponding to logical cpu 'cpu'.  Return true if so,
 * else false.  If 'thread' is non-NULL, the local thread number within the
 * core is returned in it.
 */
bool __weak arch_find_n_match_cpu_physical_id(struct device_node *cpun,
					      int cpu, unsigned int *thread)
{ … }

/**
 * of_get_cpu_node - Get device node associated with the given logical CPU
 *
 * @cpu: CPU number(logical index) for which device node is required
 * @thread: if not NULL, local thread number within the physical core is
 *          returned
 *
 * The main purpose of this function is to retrieve the device node for the
 * given logical CPU index. It should be used to initialize the of_node in
 * cpu device. Once of_node in cpu device is populated, all the further
 * references can use that instead.
 *
 * CPU logical to physical index mapping is architecture specific and is built
 * before booting secondary cores. This function uses arch_match_cpu_phys_id
 * which can be overridden by architecture specific implementation.
 *
 * Return: A node pointer for the logical cpu with refcount incremented, use
 * of_node_put() on it when done. Returns NULL if not found.
 */
struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
{ … }
EXPORT_SYMBOL(…);

/**
 * of_cpu_device_node_get: Get the CPU device_node for a given logical CPU number
 *
 * @cpu: The logical CPU number
 *
 * Return: Pointer to the device_node for CPU with its reference count
 * incremented of the given logical CPU number or NULL if the CPU device_node
 * is not found.
 */
struct device_node *of_cpu_device_node_get(int cpu)
{ … }
EXPORT_SYMBOL(…);

/**
 * of_cpu_node_to_id: Get the logical CPU number for a given device_node
 *
 * @cpu_node: Pointer to the device_node for CPU.
 *
 * Return: The logical CPU number of the given CPU device_node or -ENODEV if the
 * CPU is not found.
 */
int of_cpu_node_to_id(struct device_node *cpu_node)
{ … }
EXPORT_SYMBOL(…);

/**
 * of_get_cpu_state_node - Get CPU's idle state node at the given index
 *
 * @cpu_node: The device node for the CPU
 * @index: The index in the list of the idle states
 *
 * Two generic methods can be used to describe a CPU's idle states, either via
 * a flattened description through the "cpu-idle-states" binding or via the
 * hierarchical layout, using the "power-domains" and the "domain-idle-states"
 * bindings. This function check for both and returns the idle state node for
 * the requested index.
 *
 * Return: An idle state node if found at @index. The refcount is incremented
 * for it, so call of_node_put() on it when done. Returns NULL if not found.
 */
struct device_node *of_get_cpu_state_node(struct device_node *cpu_node,
					  int index)
{ … }
EXPORT_SYMBOL(…);