/*
 * Freescale Management Complex (MC) bus driver MSI support
 *
 * Copyright (C) 2015-2016 Freescale Semiconductor, Inc.
 * Author: German Rivera <German.Rivera@freescale.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/of_device.h>
#include <linux/of_address.h>
#include <linux/irqchip/arm-gic-v3.h>
#include <linux/of_irq.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/msi.h>
#include "../include/mc-bus.h"

/*
 * Generate a unique ID identifying the interrupt (only used within the MSI
 * irqdomain.  Combine the icid with the interrupt index.
 */
static irq_hw_number_t fsl_mc_domain_calc_hwirq(struct fsl_mc_device *dev,
						struct msi_desc *desc)
{
	/*
	 * Make the base hwirq value for ICID*10000 so it is readable
	 * as a decimal value in /proc/interrupts.
	 */
	return (irq_hw_number_t)(desc->fsl_mc.msi_index + (dev->icid * 10000));
}

static void fsl_mc_msi_set_desc(msi_alloc_info_t *arg,
				struct msi_desc *desc)
{
	arg->desc = desc;
	arg->hwirq = fsl_mc_domain_calc_hwirq(to_fsl_mc_device(desc->dev),
					      desc);
}

static void fsl_mc_msi_update_dom_ops(struct msi_domain_info *info)
{
	struct msi_domain_ops *ops = info->ops;

	if (WARN_ON(!ops))
		return;

	/*
	 * set_desc should not be set by the caller
	 */
	if (!ops->set_desc)
		ops->set_desc = fsl_mc_msi_set_desc;
}

static void __fsl_mc_msi_write_msg(struct fsl_mc_device *mc_bus_dev,
				   struct fsl_mc_device_irq *mc_dev_irq)
{
	int error;
	struct fsl_mc_device *owner_mc_dev = mc_dev_irq->mc_dev;
	struct msi_desc *msi_desc = mc_dev_irq->msi_desc;
	struct dprc_irq_cfg irq_cfg;

	/*
	 * msi_desc->msg.address is 0x0 when this function is invoked in
	 * the free_irq() code path. In this case, for the MC, we don't
	 * really need to "unprogram" the MSI, so we just return.
	 */
	if (msi_desc->msg.address_lo == 0x0 && msi_desc->msg.address_hi == 0x0)
		return;

	if (WARN_ON(!owner_mc_dev))
		return;

	irq_cfg.paddr = ((u64)msi_desc->msg.address_hi << 32) |
			msi_desc->msg.address_lo;
	irq_cfg.val = msi_desc->msg.data;
	irq_cfg.irq_num = msi_desc->irq;

	if (owner_mc_dev == mc_bus_dev) {
		/*
		 * IRQ is for the mc_bus_dev's DPRC itself
		 */
		error = dprc_set_irq(mc_bus_dev->mc_io,
				     MC_CMD_FLAG_INTR_DIS | MC_CMD_FLAG_PRI,
				     mc_bus_dev->mc_handle,
				     mc_dev_irq->dev_irq_index,
				     &irq_cfg);
		if (error < 0) {
			dev_err(&owner_mc_dev->dev,
				"dprc_set_irq() failed: %d\n", error);
		}
	} else {
		/*
		 * IRQ is for for a child device of mc_bus_dev
		 */
		error = dprc_set_obj_irq(mc_bus_dev->mc_io,
					 MC_CMD_FLAG_INTR_DIS | MC_CMD_FLAG_PRI,
					 mc_bus_dev->mc_handle,
					 owner_mc_dev->obj_desc.type,
					 owner_mc_dev->obj_desc.id,
					 mc_dev_irq->dev_irq_index,
					 &irq_cfg);
		if (error < 0) {
			dev_err(&owner_mc_dev->dev,
				"dprc_obj_set_irq() failed: %d\n", error);
		}
	}
}

/*
 * NOTE: This function is invoked with interrupts disabled
 */
static void fsl_mc_msi_write_msg(struct irq_data *irq_data,
				 struct msi_msg *msg)
{
	struct msi_desc *msi_desc = irq_data_get_msi_desc(irq_data);
	struct fsl_mc_device *mc_bus_dev = to_fsl_mc_device(msi_desc->dev);
	struct fsl_mc_bus *mc_bus = to_fsl_mc_bus(mc_bus_dev);
	struct fsl_mc_device_irq *mc_dev_irq =
		&mc_bus->irq_resources[msi_desc->fsl_mc.msi_index];

	WARN_ON(mc_dev_irq->msi_desc != msi_desc);
	msi_desc->msg = *msg;

	/*
	 * Program the MSI (paddr, value) pair in the device:
	 */
	__fsl_mc_msi_write_msg(mc_bus_dev, mc_dev_irq);
}

static void fsl_mc_msi_update_chip_ops(struct msi_domain_info *info)
{
	struct irq_chip *chip = info->chip;

	if (WARN_ON((!chip)))
		return;

	/*
	 * irq_write_msi_msg should not be set by the caller
	 */
	if (!chip->irq_write_msi_msg)
		chip->irq_write_msi_msg = fsl_mc_msi_write_msg;
}

/**
 * fsl_mc_msi_create_irq_domain - Create a fsl-mc MSI interrupt domain
 * @np:		Optional device-tree node of the interrupt controller
 * @info:	MSI domain info
 * @parent:	Parent irq domain
 *
 * Updates the domain and chip ops and creates a fsl-mc MSI
 * interrupt domain.
 *
 * Returns:
 * A domain pointer or NULL in case of failure.
 */
struct irq_domain *fsl_mc_msi_create_irq_domain(struct fwnode_handle *fwnode,
						struct msi_domain_info *info,
						struct irq_domain *parent)
{
	struct irq_domain *domain;

	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
		fsl_mc_msi_update_dom_ops(info);
	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
		fsl_mc_msi_update_chip_ops(info);

	domain = msi_create_irq_domain(fwnode, info, parent);
	if (domain)
		domain->bus_token = DOMAIN_BUS_FSL_MC_MSI;

	return domain;
}

int fsl_mc_find_msi_domain(struct device *mc_platform_dev,
			   struct irq_domain **mc_msi_domain)
{
	struct irq_domain *msi_domain;
	struct device_node *mc_of_node = mc_platform_dev->of_node;

	msi_domain = of_msi_get_domain(mc_platform_dev, mc_of_node,
				       DOMAIN_BUS_FSL_MC_MSI);
	if (!msi_domain) {
		pr_err("Unable to find fsl-mc MSI domain for %s\n",
		       mc_of_node->full_name);

		return -ENOENT;
	}

	*mc_msi_domain = msi_domain;
	return 0;
}

static void fsl_mc_msi_free_descs(struct device *dev)
{
	struct msi_desc *desc, *tmp;

	list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) {
		list_del(&desc->list);
		free_msi_entry(desc);
	}
}

static int fsl_mc_msi_alloc_descs(struct device *dev, unsigned int irq_count)

{
	unsigned int i;
	int error;
	struct msi_desc *msi_desc;

	for (i = 0; i < irq_count; i++) {
		msi_desc = alloc_msi_entry(dev, 1, NULL);
		if (!msi_desc) {
			dev_err(dev, "Failed to allocate msi entry\n");
			error = -ENOMEM;
			goto cleanup_msi_descs;
		}

		msi_desc->fsl_mc.msi_index = i;
		INIT_LIST_HEAD(&msi_desc->list);
		list_add_tail(&msi_desc->list, dev_to_msi_list(dev));
	}

	return 0;

cleanup_msi_descs:
	fsl_mc_msi_free_descs(dev);
	return error;
}

int fsl_mc_msi_domain_alloc_irqs(struct device *dev,
				 unsigned int irq_count)
{
	struct irq_domain *msi_domain;
	int error;

	if (WARN_ON(!list_empty(dev_to_msi_list(dev))))
		return -EINVAL;

	error = fsl_mc_msi_alloc_descs(dev, irq_count);
	if (error < 0)
		return error;

	msi_domain = dev_get_msi_domain(dev);
	if (WARN_ON(!msi_domain)) {
		error = -EINVAL;
		goto cleanup_msi_descs;
	}

	/*
	 * NOTE: Calling this function will trigger the invocation of the
	 * its_fsl_mc_msi_prepare() callback
	 */
	error = msi_domain_alloc_irqs(msi_domain, dev, irq_count);

	if (error) {
		dev_err(dev, "Failed to allocate IRQs\n");
		goto cleanup_msi_descs;
	}

	return 0;

cleanup_msi_descs:
	fsl_mc_msi_free_descs(dev);
	return error;
}

void fsl_mc_msi_domain_free_irqs(struct device *dev)
{
	struct irq_domain *msi_domain;

	msi_domain = dev_get_msi_domain(dev);
	if (WARN_ON(!msi_domain))
		return;

	msi_domain_free_irqs(msi_domain, dev);

	if (WARN_ON(list_empty(dev_to_msi_list(dev))))
		return;

	fsl_mc_msi_free_descs(dev);
}