211 lines
6.2 KiB
C
211 lines
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/cpu.h>
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#include <linux/kernel.h>
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#include <linux/of.h>
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/**
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* of_get_cpu_hwid - Get the hardware ID from a CPU device node
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*
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* @cpun: CPU number(logical index) for which device node is required
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* @thread: The local thread number to get the hardware ID for.
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*
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* Return: The hardware ID for the CPU node or ~0ULL if not found.
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*/
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u64 of_get_cpu_hwid(struct device_node *cpun, unsigned int thread)
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{
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const __be32 *cell;
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int ac, len;
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ac = of_n_addr_cells(cpun);
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cell = of_get_property(cpun, "reg", &len);
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if (!cell || !ac || ((sizeof(*cell) * ac * (thread + 1)) > len))
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return ~0ULL;
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cell += ac * thread;
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return of_read_number(cell, ac);
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}
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/*
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* arch_match_cpu_phys_id - Match the given logical CPU and physical id
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*
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* @cpu: logical cpu index of a core/thread
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* @phys_id: physical identifier of a core/thread
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*
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* CPU logical to physical index mapping is architecture specific.
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* However this __weak function provides a default match of physical
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* id to logical cpu index. phys_id provided here is usually values read
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* from the device tree which must match the hardware internal registers.
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*
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* Returns true if the physical identifier and the logical cpu index
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* correspond to the same core/thread, false otherwise.
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*/
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bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id)
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{
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return (u32)phys_id == cpu;
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}
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/*
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* Checks if the given "prop_name" property holds the physical id of the
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* core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not
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* NULL, local thread number within the core is returned in it.
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*/
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static bool __of_find_n_match_cpu_property(struct device_node *cpun,
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const char *prop_name, int cpu, unsigned int *thread)
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{
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const __be32 *cell;
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int ac, prop_len, tid;
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u64 hwid;
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ac = of_n_addr_cells(cpun);
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cell = of_get_property(cpun, prop_name, &prop_len);
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if (!cell && !ac && arch_match_cpu_phys_id(cpu, 0))
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return true;
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if (!cell || !ac)
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return false;
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prop_len /= sizeof(*cell) * ac;
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for (tid = 0; tid < prop_len; tid++) {
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hwid = of_read_number(cell, ac);
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if (arch_match_cpu_phys_id(cpu, hwid)) {
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if (thread)
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*thread = tid;
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return true;
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}
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cell += ac;
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}
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return false;
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}
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/*
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* arch_find_n_match_cpu_physical_id - See if the given device node is
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* for the cpu corresponding to logical cpu 'cpu'. Return true if so,
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* else false. If 'thread' is non-NULL, the local thread number within the
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* core is returned in it.
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*/
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bool __weak arch_find_n_match_cpu_physical_id(struct device_node *cpun,
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int cpu, unsigned int *thread)
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{
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/* Check for non-standard "ibm,ppc-interrupt-server#s" property
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* for thread ids on PowerPC. If it doesn't exist fallback to
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* standard "reg" property.
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*/
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if (IS_ENABLED(CONFIG_PPC) &&
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__of_find_n_match_cpu_property(cpun,
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"ibm,ppc-interrupt-server#s",
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cpu, thread))
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return true;
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return __of_find_n_match_cpu_property(cpun, "reg", cpu, thread);
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}
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/**
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* of_get_cpu_node - Get device node associated with the given logical CPU
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*
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* @cpu: CPU number(logical index) for which device node is required
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* @thread: if not NULL, local thread number within the physical core is
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* returned
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*
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* The main purpose of this function is to retrieve the device node for the
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* given logical CPU index. It should be used to initialize the of_node in
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* cpu device. Once of_node in cpu device is populated, all the further
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* references can use that instead.
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*
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* CPU logical to physical index mapping is architecture specific and is built
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* before booting secondary cores. This function uses arch_match_cpu_phys_id
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* which can be overridden by architecture specific implementation.
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*
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* Return: A node pointer for the logical cpu with refcount incremented, use
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* of_node_put() on it when done. Returns NULL if not found.
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*/
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struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
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{
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struct device_node *cpun;
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for_each_of_cpu_node(cpun) {
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if (arch_find_n_match_cpu_physical_id(cpun, cpu, thread))
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return cpun;
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}
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return NULL;
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}
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EXPORT_SYMBOL(of_get_cpu_node);
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/**
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* of_cpu_device_node_get: Get the CPU device_node for a given logical CPU number
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*
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* @cpu: The logical CPU number
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*
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* Return: Pointer to the device_node for CPU with its reference count
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* incremented of the given logical CPU number or NULL if the CPU device_node
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* is not found.
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*/
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struct device_node *of_cpu_device_node_get(int cpu)
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{
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struct device *cpu_dev;
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cpu_dev = get_cpu_device(cpu);
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if (!cpu_dev)
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return of_get_cpu_node(cpu, NULL);
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return of_node_get(cpu_dev->of_node);
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}
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EXPORT_SYMBOL(of_cpu_device_node_get);
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/**
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* of_cpu_node_to_id: Get the logical CPU number for a given device_node
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*
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* @cpu_node: Pointer to the device_node for CPU.
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*
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* Return: The logical CPU number of the given CPU device_node or -ENODEV if the
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* CPU is not found.
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*/
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int of_cpu_node_to_id(struct device_node *cpu_node)
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{
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int cpu;
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bool found = false;
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struct device_node *np;
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for_each_possible_cpu(cpu) {
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np = of_cpu_device_node_get(cpu);
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found = (cpu_node == np);
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of_node_put(np);
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if (found)
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return cpu;
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}
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return -ENODEV;
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}
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EXPORT_SYMBOL(of_cpu_node_to_id);
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/**
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* of_get_cpu_state_node - Get CPU's idle state node at the given index
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*
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* @cpu_node: The device node for the CPU
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* @index: The index in the list of the idle states
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*
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* Two generic methods can be used to describe a CPU's idle states, either via
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* a flattened description through the "cpu-idle-states" binding or via the
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* hierarchical layout, using the "power-domains" and the "domain-idle-states"
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* bindings. This function check for both and returns the idle state node for
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* the requested index.
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*
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* Return: An idle state node if found at @index. The refcount is incremented
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* for it, so call of_node_put() on it when done. Returns NULL if not found.
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*/
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struct device_node *of_get_cpu_state_node(struct device_node *cpu_node,
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int index)
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{
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struct of_phandle_args args;
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int err;
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err = of_parse_phandle_with_args(cpu_node, "power-domains",
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"#power-domain-cells", 0, &args);
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if (!err) {
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struct device_node *state_node =
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of_parse_phandle(args.np, "domain-idle-states", index);
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of_node_put(args.np);
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if (state_node)
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return state_node;
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}
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return of_parse_phandle(cpu_node, "cpu-idle-states", index);
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}
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EXPORT_SYMBOL(of_get_cpu_state_node);
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