U-Boot

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2016, NVIDIA CORPORATION.
 */

#define LOG_CATEGORY UCLASS_POWER_DOMAIN

#include <dm.h>
#include <log.h>
#include <malloc.h>
#include <power-domain.h>
#include <power-domain-uclass.h>
#include <dm/device-internal.h>

struct power_domain_priv {
	int *on_count;
};

static inline struct power_domain_ops *power_domain_dev_ops(struct udevice *dev)
{
	return (struct power_domain_ops *)dev->driver->ops;
}

static int power_domain_of_xlate_default(struct power_domain *power_domain,
					 struct ofnode_phandle_args *args)
{
	debug("%s(power_domain=%p)\n", __func__, power_domain);

	if (args->args_count != 1) {
		debug("Invalid args_count: %d\n", args->args_count);
		return -EINVAL;
	}

	power_domain->id = args->args[0];

	return 0;
}

int power_domain_get_by_index(struct udevice *dev,
			      struct power_domain *power_domain, int index)
{
	struct ofnode_phandle_args args;
	int ret;
	struct udevice *dev_power_domain;
	struct power_domain_ops *ops;

	debug("%s(dev=%p, power_domain=%p)\n", __func__, dev, power_domain);

	ret = dev_read_phandle_with_args(dev, "power-domains",
					 "#power-domain-cells", 0, index,
					 &args);
	if (ret) {
		debug("%s: dev_read_phandle_with_args failed: %d\n",
		      __func__, ret);
		return ret;
	}

	ret = uclass_get_device_by_ofnode(UCLASS_POWER_DOMAIN, args.node,
					  &dev_power_domain);
	if (ret) {
		debug("%s: uclass_get_device_by_ofnode failed: %d\n",
		      __func__, ret);
		return ret;
	}
	ops = power_domain_dev_ops(dev_power_domain);

	power_domain->dev = dev_power_domain;
	if (ops->of_xlate)
		ret = ops->of_xlate(power_domain, &args);
	else
		ret = power_domain_of_xlate_default(power_domain, &args);
	if (ret) {
		debug("of_xlate() failed: %d\n", ret);
		return ret;
	}

	ret = ops->request ? ops->request(power_domain) : 0;
	if (ret) {
		debug("ops->request() failed: %d\n", ret);
		return ret;
	}

	return 0;
}

int power_domain_get_by_name(struct udevice *dev,
			     struct power_domain *power_domain, const char *name)
{
	int index;

	index = dev_read_stringlist_search(dev, "power-domain-names", name);
	if (index < 0) {
		debug("fdt_stringlist_search() failed: %d\n", index);
		return index;
	}

	return power_domain_get_by_index(dev, power_domain, index);
}

int power_domain_get(struct udevice *dev, struct power_domain *power_domain)
{
	return power_domain_get_by_index(dev, power_domain, 0);
}

int power_domain_free(struct power_domain *power_domain)
{
	struct power_domain_ops *ops = power_domain_dev_ops(power_domain->dev);

	debug("%s(power_domain=%p)\n", __func__, power_domain);

	return ops->rfree ? ops->rfree(power_domain) : 0;
}

int power_domain_on_lowlevel(struct power_domain *power_domain)
{
	struct power_domain_priv *priv = dev_get_uclass_priv(power_domain->dev);
	struct power_domain_plat *plat = dev_get_uclass_plat(power_domain->dev);
	struct power_domain_ops *ops = power_domain_dev_ops(power_domain->dev);
	int *on_count = plat->subdomains ? &priv->on_count[power_domain->id] : NULL;
	int ret;

	/* Refcounting is not enabled on all drivers by default */
	if (on_count) {
		debug("Enable power domain %s.%ld: %d -> %d (%s)\n",
		      power_domain->dev->name, power_domain->id, *on_count, *on_count + 1,
		      (((*on_count + 1) > 1) ? "EALREADY" : "todo"));

		(*on_count)++;
		if (*on_count > 1)
			return -EALREADY;
	}

	ret = ops->on ? ops->on(power_domain) : 0;
	if (ret) {
		if (on_count)
			(*on_count)--;
		return ret;
	}

	return 0;
}

int power_domain_off_lowlevel(struct power_domain *power_domain)
{
	struct power_domain_priv *priv = dev_get_uclass_priv(power_domain->dev);
	struct power_domain_plat *plat = dev_get_uclass_plat(power_domain->dev);
	struct power_domain_ops *ops = power_domain_dev_ops(power_domain->dev);
	int *on_count = plat->subdomains ? &priv->on_count[power_domain->id] : NULL;
	int ret;

	/* Refcounting is not enabled on all drivers by default */
	if (on_count) {
		debug("Disable power domain %s.%ld: %d -> %d (%s%s)\n",
		      power_domain->dev->name, power_domain->id, *on_count, *on_count - 1,
		      (((*on_count) <= 0) ? "EALREADY" : ""),
		      (((*on_count - 1) > 0) ? "BUSY" : "todo"));

		if (*on_count <= 0)
			return -EALREADY;

		(*on_count)--;
		if (*on_count > 0)
			return -EBUSY;
	}

	ret = ops->off ? ops->off(power_domain) : 0;
	if (ret) {
		if (on_count)
			(*on_count)++;

		return ret;
	}

	return 0;
}

#if CONFIG_IS_ENABLED(OF_REAL)
static int dev_power_domain_ctrl(struct udevice *dev, bool on)
{
	struct power_domain pd;
	int i, count, ret = 0;

	count = dev_count_phandle_with_args(dev, "power-domains",
					    "#power-domain-cells", 0);
	for (i = 0; i < count; i++) {
		ret = power_domain_get_by_index(dev, &pd, i);
		if (ret)
			return ret;
		if (on)
			ret = power_domain_on(&pd);
		else
			ret = power_domain_off(&pd);
	}

	/*
	 * For platforms with parent and child power-domain devices
	 * we may not run device_remove() on the power-domain parent
	 * because it will result in removing its children and switching
	 * off their power-domain parent. So we will get here again and
	 * again and will be stuck in an endless loop.
	 */
	if (count > 0 && !on && dev_get_parent(dev) == pd.dev &&
	    device_get_uclass_id(dev) == UCLASS_POWER_DOMAIN)
		return ret;

	/*
	 * power_domain_get() bound the device, thus
	 * we must remove it again to prevent unbinding
	 * active devices (which would result in unbind
	 * error).
	 */
	if (count > 0 && !on)
		device_remove(pd.dev, DM_REMOVE_NORMAL);

	return ret;
}

int dev_power_domain_on(struct udevice *dev)
{
	return dev_power_domain_ctrl(dev, true);
}

int dev_power_domain_off(struct udevice *dev)
{
	return dev_power_domain_ctrl(dev, false);
}
#endif  /* OF_REAL */

static int power_domain_post_probe(struct udevice *dev)
{
	struct power_domain_priv *priv = dev_get_uclass_priv(dev);
	struct power_domain_plat *plat = dev_get_uclass_plat(dev);

	if (plat->subdomains) {
		priv->on_count = calloc(sizeof(int), plat->subdomains);
		if (!priv->on_count)
			return -ENOMEM;
	}

	return 0;
}

static int power_domain_pre_remove(struct udevice *dev)
{
	struct power_domain_priv *priv = dev_get_uclass_priv(dev);
	struct power_domain_plat *plat = dev_get_uclass_plat(dev);

	if (plat->subdomains)
		free(priv->on_count);

	return 0;
}

UCLASS_DRIVER(power_domain) = {
	.id		= UCLASS_POWER_DOMAIN,
	.name		= "power_domain",
	.post_probe	= power_domain_post_probe,
	.pre_remove	= power_domain_pre_remove,
	.per_device_auto = sizeof(struct power_domain_priv),
	.per_device_plat_auto = sizeof(struct power_domain_plat),
};