of: Move CPU node related functions to their own file

drivers/of/base.c is quite long and we've accumulated a number of CPU
node functions. Let's move them to a new file, cpu.c, along with the
lone of_cpu_device_node_get() in of_device.h. Moving the declaration has
no effect yet as of.h is included by of_device.h. This serves as
preparation to disentangle the includes in of_device.h and
of_platform.h.

Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20230329-dt-cpu-header-cleanups-v1-4-581e2605fe47@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>

3 files changed, 211 insertions, 188 deletions

diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index e0360a44306e..10f704592561 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
-obj-y = base.o device.o platform.o property.o
+obj-y = base.o cpu.o device.o platform.o property.o
 obj-$(CONFIG_OF_KOBJ) += kobj.o
 obj-$(CONFIG_OF_DYNAMIC) += dynamic.o
 obj-$(CONFIG_OF_FLATTREE) += fdt.o
diff --git a/drivers/of/base.c b/drivers/of/base.c
index ac6fde53342f..7f1720af813c 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -287,193 +287,6 @@ 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
- *
- * @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_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);
-
-/**
  * __of_device_is_compatible() - Check if the node matches given constraints
  * @device: pointer to node
  * @compat: required compatible string, NULL or "" for any match
diff --git a/drivers/of/cpu.c b/drivers/of/cpu.c
new file mode 100644
index 000000000000..d17b2f851082
--- /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);