path: root/drivers/opp/of.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Generic OPP OF helpers
 *
 * Copyright (C) 2009-2010 Texas Instruments Incorporated.
 *	Nishanth Menon
 *	Romit Dasgupta
 *	Kevin Hilman
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/pm_domain.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/energy_model.h>

#include "opp.h"

/* OPP tables with uninitialized required OPPs, protected by opp_table_lock */
static LIST_HEAD(lazy_opp_tables);

/*
 * Returns opp descriptor node for a device node, caller must
 * do of_node_put().
 */
static struct device_node *_opp_of_get_opp_desc_node(struct device_node *np,
						     int index)
{
	/* "operating-points-v2" can be an array for power domain providers */
	return of_parse_phandle(np, "operating-points-v2", index);
}

/* Returns opp descriptor node for a device, caller must do of_node_put() */
struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev)
{
	return _opp_of_get_opp_desc_node(dev->of_node, 0);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_opp_desc_node);

struct opp_table *_managed_opp(struct device *dev, int index)
{
	struct opp_table *opp_table, *managed_table = NULL;
	struct device_node *np __free(device_node);

	np = _opp_of_get_opp_desc_node(dev->of_node, index);
	if (!np)
		return NULL;

	list_for_each_entry(opp_table, &opp_tables, node) {
		if (opp_table->np == np) {
			/*
			 * Multiple devices can point to the same OPP table and
			 * so will have same node-pointer, np.
			 *
			 * But the OPPs will be considered as shared only if the
			 * OPP table contains a "opp-shared" property.
			 */
			if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED)
				managed_table = dev_pm_opp_get_opp_table_ref(opp_table);

			break;
		}
	}

	return managed_table;
}

/* The caller must call dev_pm_opp_put() after the OPP is used */
static struct dev_pm_opp *_find_opp_of_np(struct opp_table *opp_table,
					  struct device_node *opp_np)
{
	struct dev_pm_opp *opp;

	guard(mutex)(&opp_table->lock);

	list_for_each_entry(opp, &opp_table->opp_list, node) {
		if (opp->np == opp_np)
			return dev_pm_opp_get(opp);
	}

	return NULL;
}

static struct device_node *of_parse_required_opp(struct device_node *np,
						 int index)
{
	return of_parse_phandle(np, "required-opps", index);
}

/* The caller must call dev_pm_opp_put_opp_table() after the table is used */
static struct opp_table *_find_table_of_opp_np(struct device_node *opp_np)
{
	struct device_node *opp_table_np __free(device_node);
	struct opp_table *opp_table;

	opp_table_np = of_get_parent(opp_np);
	if (!opp_table_np)
		return ERR_PTR(-ENODEV);

	guard(mutex)(&opp_table_lock);

	list_for_each_entry(opp_table, &opp_tables, node) {
		if (opp_table_np == opp_table->np)
			return dev_pm_opp_get_opp_table_ref(opp_table);
	}

	return ERR_PTR(-ENODEV);
}

/* Free resources previously acquired by _opp_table_alloc_required_tables() */
static void _opp_table_free_required_tables(struct opp_table *opp_table)
{
	struct opp_table **required_opp_tables = opp_table->required_opp_tables;
	int i;

	if (!required_opp_tables)
		return;

	for (i = 0; i < opp_table->required_opp_count; i++) {
		if (IS_ERR_OR_NULL(required_opp_tables[i]))
			continue;

		dev_pm_opp_put_opp_table(required_opp_tables[i]);
	}

	kfree(required_opp_tables);

	opp_table->required_opp_count = 0;
	opp_table->required_opp_tables = NULL;

	guard(mutex)(&opp_table_lock);
	list_del(&opp_table->lazy);
}

/*
 * Populate all devices and opp tables which are part of "required-opps" list.
 * Checking only the first OPP node should be enough.
 */
static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
					     struct device *dev,
					     struct device_node *opp_np)
{
	struct opp_table **required_opp_tables;
	struct device_node *np __free(device_node);
	bool lazy = false;
	int count, i, size;

	/* Traversing the first OPP node is all we need */
	np = of_get_next_available_child(opp_np, NULL);
	if (!np) {
		dev_warn(dev, "Empty OPP table\n");
		return;
	}

	count = of_count_phandle_with_args(np, "required-opps", NULL);
	if (count <= 0)
		return;

	size = sizeof(*required_opp_tables) + sizeof(*opp_table->required_devs);
	required_opp_tables = kcalloc(count, size, GFP_KERNEL);
	if (!required_opp_tables)
		return;

	opp_table->required_opp_tables = required_opp_tables;
	opp_table->required_devs = (void *)(required_opp_tables + count);
	opp_table->required_opp_count = count;

	for (i = 0; i < count; i++) {
		struct device_node *required_np __free(device_node);

		required_np = of_parse_required_opp(np, i);
		if (!required_np) {
			_opp_table_free_required_tables(opp_table);
			return;
		}

		required_opp_tables[i] = _find_table_of_opp_np(required_np);

		if (IS_ERR(required_opp_tables[i]))
			lazy = true;
	}

	/* Let's do the linking later on */
	if (lazy) {
		/*
		 * The OPP table is not held while allocating the table, take it
		 * now to avoid corruption to the lazy_opp_tables list.
		 */
		guard(mutex)(&opp_table_lock);
		list_add(&opp_table->lazy, &lazy_opp_tables);
	}
}

void _of_init_opp_table(struct opp_table *opp_table, struct device *dev,
			int index)
{
	struct device_node *np __free(device_node), *opp_np;
	u32 val;

	/*
	 * Only required for backward compatibility with v1 bindings, but isn't
	 * harmful for other cases. And so we do it unconditionally.
	 */
	np = of_node_get(dev->of_node);
	if (!np)
		return;

	if (!of_property_read_u32(np, "clock-latency", &val))
		opp_table->clock_latency_ns_max = val;
	of_property_read_u32(np, "voltage-tolerance",
			     &opp_table->voltage_tolerance_v1);

	if (of_property_present(np, "#power-domain-cells"))
		opp_table->is_genpd = true;

	/* Get OPP table node */
	opp_np = _opp_of_get_opp_desc_node(np, index);
	if (!opp_np)
		return;

	if