// SPDX-License-Identifier: GPL-2.0
/*
 * Freescale Management Complex (MC) bus driver MSI support
 *
 * Copyright (C) 2015-2016 Freescale Semiconductor, Inc.
 * Author: German Rivera <German.Rivera@freescale.com>
 *
 */

#include <linux/of_device.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/msi.h>
#include <linux/acpi_iort.h>

#include "fsl-mc-private.h"

#ifdef GENERIC_MSI_DOMAIN_OPS
/*
 * 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);
}
#else
#define fsl_mc_msi_set_desc NULL
#endif

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

        if (!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 (!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];

        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 (!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
 * @fwnode:     Optional firmware 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 (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE)))
                info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
        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)
                irq_domain_update_bus_token(domain, DOMAIN_BUS_FSL_MC_MSI);

        return domain;
}

struct irq_domain *fsl_mc_find_msi_domain(struct device *dev)
{
        struct device *root_dprc_dev;
        struct device *bus_dev;
        struct irq_domain *msi_domain;
        struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);

        fsl_mc_get_root_dprc(dev, &root_dprc_dev);
        bus_dev = root_dprc_dev->parent;

        if (bus_dev->of_node) {
                msi_domain = of_msi_map_get_device_domain(dev,
                                                  mc_dev->icid,
                                                  DOMAIN_BUS_FSL_MC_MSI);

                /*
                 * if the msi-map property is missing assume that all the
                 * child containers inherit the domain from the parent
                 */
                if (!msi_domain)

                        msi_domain = of_msi_get_domain(bus_dev,
                                                bus_dev->of_node,
                                                DOMAIN_BUS_FSL_MC_MSI);
        } else {
                msi_domain = iort_get_device_domain(dev, mc_dev->icid,
                                                    DOMAIN_BUS_FSL_MC_MSI);
        }

        return msi_domain;
}

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 (!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 (!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 (!msi_domain)
                return;

        msi_domain_free_irqs(msi_domain, dev);

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

        fsl_mc_msi_free_descs(dev);
}