#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/slab.h>

static LIST_HEAD(irq_domain_list);
static DEFINE_MUTEX(irq_domain_mutex);

/**
 * irq_domain_add() - Register an irq_domain
 * @domain: ptr to initialized irq_domain structure
 *
 * Adds a irq_domain structure.  The irq_domain must at a minimum be
 * initialized with an ops structure pointer, and either a ->to_irq hook or
 * a valid irq_base value.  The irq range must be mutually exclusive with
 * domains already registered. Everything else is optional.
 */
int irq_domain_add(struct irq_domain *domain)
{
	struct irq_domain *curr;
	uint32_t d_highirq = domain->irq_base + domain->nr_irq - 1;

	if (!domain->nr_irq)
		return -EINVAL;

	mutex_lock(&irq_domain_mutex);
	/* insert in ascending order of domain->irq_base */
	list_for_each_entry(curr, &irq_domain_list, list) {
		uint32_t c_highirq = curr->irq_base + curr->nr_irq - 1;
		if (domain->irq_base < curr->irq_base &&
		    d_highirq < curr->irq_base) {
			break;
		}
		if (d_highirq <= c_highirq) {
			mutex_unlock(&irq_domain_mutex);
			return -EINVAL;
		}
	}
	list_add_tail(&domain->list, &curr->list);
	mutex_unlock(&irq_domain_mutex);

	return 0;
}

/**
 * irq_domain_register() - Register an entire irq_domain
 * @domain: ptr to initialized irq_domain structure
 *
 * Registers the entire irq_domain.  The irq_domain must at a minimum be
 * initialized with an ops structure pointer, and either a ->to_irq hook or
 * a valid irq_base value.  Everything else is optional.
 */
void irq_domain_register(struct irq_domain *domain)
{
	struct irq_data *d;
	int hwirq, irq;

	irq_domain_for_each_irq(domain, hwirq, irq) {
		d = irq_get_irq_data(irq);
		if (!d) {
			WARN(1, "error: assigning domain to non existant irq_desc");
			return;
		}
		if (d->domain) {
			/* things are broken; just report, don't clean up */
			WARN(1, "error: irq_desc already assigned to a domain");
			return;
		}
		d->domain = domain;
		d->hwirq = hwirq;
	}
}

/**
 * irq_domain_register_irq() - Register an irq_domain
 * @domain: ptr to initialized irq_domain structure
 * @hwirq: irq_domain hwirq to register
 *
 * Registers a specific hwirq within the irq_domain.  The irq_domain
 * must at a minimum be initialized with an ops structure pointer, and
 * either a ->to_irq hook or a valid irq_base value.  Everything else is
 * optional.
 */
void irq_domain_register_irq(struct irq_domain *domain, int hwirq)
{
	struct irq_data *d;

	d = irq_get_irq_data(irq_domain_to_irq(domain, hwirq));
	if (!d) {
		WARN(1, "error: assigning domain to non existant irq_desc");
		return;
	}
	if (d->domain) {
		/* things are broken; just report, don't clean up */
		WARN(1, "error: irq_desc already assigned to a domain");
		return;
	}
	d->domain = domain;
	d->hwirq = hwirq;
}

/**
 * irq_domain_del() - Removes a irq_domain from the system
 * @domain: ptr to registered irq_domain.
 */
void irq_domain_del(struct irq_domain *domain)
{
	mutex_lock(&irq_domain_mutex);
	list_del(&domain->list);
	mutex_unlock(&irq_domain_mutex);
}

/**
 * irq_domain_unregister() - Unregister an irq_domain
 * @domain: ptr to registered irq_domain.
 */
void irq_domain_unregister(struct irq_domain *domain)
{
	struct irq_data *d;
	int hwirq, irq;

	/* Clear the irq_domain assignments */
	irq_domain_for_each_irq(domain, hwirq, irq) {
		d = irq_get_irq_data(irq);
		d->domain = NULL;
	}
}

/**
 * irq_domain_unregister_irq() - Unregister a hwirq within a irq_domain
 * @domain: ptr to registered irq_domain.
 * @hwirq: irq_domain hwirq to unregister.
 */
void irq_domain_unregister_irq(struct irq_domain *domain, int hwirq)
{
	struct irq_data *d;

	/* Clear the irq_domain assignment */
	d = irq_get_irq_data(irq_domain_to_irq(domain, hwirq));
	d->domain = NULL;
}

/**
 * irq_domain_find_free_range() - Find an available irq range
 * @from: lowest logical irq number to request from
 * @cnt: number of interrupts to search for
 *
 * Finds an available logical irq range from the domains specified
 * on the system. The from parameter can be used to allocate a range
 * at least as great as the specified irq number.
 */
int irq_domain_find_free_range(unsigned int from, unsigned int cnt)
{
	struct irq_domain *curr, *prev = NULL;

	if (list_empty(&irq_domain_list))
		return from;

	list_for_each_entry(curr, &irq_domain_list, list) {
		if (prev == NULL) {
			if ((from + cnt - 1) < curr->irq_base)
				return from;
		} else {
			uint32_t p_next_irq = prev->irq_base + prev->nr_irq;
			uint32_t start_irq;
			if (from >= curr->irq_base)
				continue;
			if (from < p_next_irq)
				start_irq = p_next_irq;
			else
				start_irq = from;
			if ((curr->irq_base - start_irq) >= cnt)
				return p_next_irq;
		}
		prev = curr;
	}
	curr = list_entry(curr->list.prev, struct irq_domain, list);

	return from > curr->irq_base + curr->nr_irq ?
	       from : curr->irq_base + curr->nr_irq;
}

#if defined(CONFIG_OF_IRQ)
/**
 * irq_create_of_mapping() - Map a linux irq number from a DT interrupt spec
 *
 * Used by the device tree interrupt mapping code to translate a device tree
 * interrupt specifier to a valid linux irq number.  Returns either a valid
 * linux IRQ number or 0.
 *
 * When the caller no longer need the irq number returned by this function it
 * should arrange to call irq_dispose_mapping().
 */
unsigned int irq_create_of_mapping(struct device_node *controller,
				   const u32 *intspec, unsigned int intsize)
{
	struct irq_domain *domain;
	unsigned long hwirq;
	unsigned int irq, type;
	int rc = -EINVAL;

	/* Find a domain which can translate the irq spec */
	mutex_lock(&irq_domain_mutex);
	list_for_each_entry(domain, &irq_domain_list, list) {
		if (!domain->ops->dt_translate)
			continue;

		rc = domain->ops->dt_translate(domain, controller,
					intspec, intsize, &hwirq, &type);
		if (rc == 0)
			break;
	}
	mutex_unlock(&irq_domain_mutex);

	if (rc != 0)
		return 0;

	irq = irq_domain_to_irq(domain, hwirq);
	if (type != IRQ_TYPE_NONE)
		irq_set_irq_type(irq, type);
	pr_debug("%s: mapped hwirq=%i to irq=%i, flags=%x\n",
		 controller->full_name, (int)hwirq, irq, type);
	return irq;
}
EXPORT_SYMBOL_GPL(irq_create_of_mapping);

/**
 * irq_dispose_mapping() - Discard a mapping created by irq_create_of_mapping()
 * @irq: linux irq number to be discarded
 *
 * Calling this function indicates the caller no longer needs a reference to
 * the linux irq number returned by a prior call to irq_create_of_mapping().
 */
void irq_dispose_mapping(unsigned int irq)
{
	/*
	 * nothing yet; will be filled when support for dynamic allocation of
	 * irq_descs is added to irq_domain
	 */
}
EXPORT_SYMBOL_GPL(irq_dispose_mapping);

int irq_domain_simple_dt_translate(struct irq_domain *d,
			    struct device_node *controller,
			    const u32 *intspec, unsigned int intsize,
			    unsigned long *out_hwirq, unsigned int *out_type)
{
	if (d->of_node != controller)
		return -EINVAL;
	if (intsize < 1)
		return -EINVAL;

	*out_hwirq = intspec[0];
	*out_type = IRQ_TYPE_NONE;
	if (intsize > 1)
		*out_type = intspec[1] & IRQ_TYPE_SENSE_MASK;
	return 0;
}

struct irq_domain_ops irq_domain_simple_ops = {
	.dt_translate = irq_domain_simple_dt_translate,
};
EXPORT_SYMBOL_GPL(irq_domain_simple_ops);

/**
 * irq_domain_create_simple() - Set up a 'simple' translation range
 */
void irq_domain_add_simple(struct device_node *controller, int irq_base)
{
	struct irq_domain *domain;
	int rc;

	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
	if (!domain) {
		WARN_ON(1);
		return;
	}

	domain->irq_base = irq_base;
	domain->of_node = of_node_get(controller);
	domain->ops = &irq_domain_simple_ops;
	rc = irq_domain_add(domain);
	if (rc) {
		WARN(1, "Unable to create irq domain\n");
		return;
	}
	irq_domain_register(domain);
}
EXPORT_SYMBOL_GPL(irq_domain_add_simple);

void irq_domain_generate_simple(const struct of_device_id *match,
				u64 phys_base, unsigned int irq_start)
{
	struct device_node *node;
	pr_info("looking for phys_base=%llx, irq_start=%i\n",
		(unsigned long long) phys_base, (int) irq_start);
	node = of_find_matching_node_by_address(NULL, match, phys_base);
	if (node)
		irq_domain_add_simple(node, irq_start);
	else
		pr_info("no node found\n");
}
EXPORT_SYMBOL_GPL(irq_domain_generate_simple);
#endif /* CONFIG_OF_IRQ */