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-rw-r--r--drivers/of/cpu.c210
1 files changed, 210 insertions, 0 deletions
diff --git a/drivers/of/cpu.c b/drivers/of/cpu.c
new file mode 100644
index 0000000000..d17b2f8510
--- /dev/null
+++ b/drivers/of/cpu.c
@@ -0,0 +1,210 @@
+// 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)
+{
+ 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
+ *
+ * @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)
+{
+ return (u32)phys_id == cpu;
+}
+
+/*
+ * 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)
+{
+ const __be32 *cell;
+ int ac, prop_len, tid;
+ u64 hwid;
+
+ ac = of_n_addr_cells(cpun);
+ cell = of_get_property(cpun, prop_name, &prop_len);
+ if (!cell && !ac && arch_match_cpu_phys_id(cpu, 0))
+ return true;
+ if (!cell || !ac)
+ return false;
+ prop_len /= sizeof(*cell) * ac;
+ for (tid = 0; tid < prop_len; tid++) {
+ hwid = of_read_number(cell, ac);
+ if (arch_match_cpu_phys_id(cpu, hwid)) {
+ if (thread)
+ *thread = tid;
+ return true;
+ }
+ cell += ac;
+ }
+ return false;
+}
+
+/*
+ * 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)
+{
+ /* Check for non-standard "ibm,ppc-interrupt-server#s" property
+ * for thread ids on PowerPC. If it doesn't exist fallback to
+ * standard "reg" property.
+ */
+ if (IS_ENABLED(CONFIG_PPC) &&
+ __of_find_n_match_cpu_property(cpun,
+ "ibm,ppc-interrupt-server#s",
+ cpu, thread))
+ return true;
+
+ return __of_find_n_match_cpu_property(cpun, "reg", cpu, 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)
+{
+ struct device_node *cpun;
+
+ for_each_of_cpu_node(cpun) {
+ if (arch_find_n_match_cpu_physical_id(cpun, cpu, thread))
+ return cpun;
+ }
+ return NULL;
+}
+EXPORT_SYMBOL(of_get_cpu_node);
+
+/**
+ * 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)
+{
+ struct device *cpu_dev;
+ cpu_dev = get_cpu_device(cpu);
+ if (!cpu_dev)
+ return of_get_cpu_node(cpu, NULL);
+ return of_node_get(cpu_dev->of_node);
+}
+EXPORT_SYMBOL(of_cpu_device_node_get);
+
+/**
+ * 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)
+{
+ 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_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)
+{
+ struct of_phandle_args args;
+ int err;
+
+ err = of_parse_phandle_with_args(cpu_node, "power-domains",
+ "#power-domain-cells", 0, &args);
+ if (!err) {
+ struct device_node *state_node =
+ of_parse_phandle(args.np, "domain-idle-states", index);
+
+ of_node_put(args.np);
+ if (state_node)
+ return state_node;
+ }
+
+ return of_parse_phandle(cpu_node, "cpu-idle-states", index);
+}
+EXPORT_SYMBOL(of_get_cpu_state_node);