// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
 */

#include <linux/vfio.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/eventfd.h>
#include <linux/msi.h>
#include <linux/interrupt.h>

#include "linux/cdx/cdx_bus.h"
#include "private.h"

static irqreturn_t vfio_cdx_msihandler(int irq_no, void *arg)
{
        struct eventfd_ctx *trigger = arg;

        eventfd_signal(trigger);
        return IRQ_HANDLED;
}

static int vfio_cdx_msi_enable(struct vfio_cdx_device *vdev, int nvec)
{
        struct cdx_device *cdx_dev = to_cdx_device(vdev->vdev.dev);
        struct device *dev = vdev->vdev.dev;
        int msi_idx, ret;

        vdev->cdx_irqs = kzalloc_objs(struct vfio_cdx_irq, nvec);
        if (!vdev->cdx_irqs)
                return -ENOMEM;

        ret = cdx_enable_msi(cdx_dev);
        if (ret) {
                kfree(vdev->cdx_irqs);
                return ret;
        }

        /* Allocate cdx MSIs */
        ret = msi_domain_alloc_irqs(dev, MSI_DEFAULT_DOMAIN, nvec);
        if (ret) {
                cdx_disable_msi(cdx_dev);
                kfree(vdev->cdx_irqs);
                return ret;
        }

        for (msi_idx = 0; msi_idx < nvec; msi_idx++)
                vdev->cdx_irqs[msi_idx].irq_no = msi_get_virq(dev, msi_idx);

        vdev->msi_count = nvec;
        vdev->config_msi = 1;

        return 0;
}

static int vfio_cdx_msi_set_vector_signal(struct vfio_cdx_device *vdev,
                                          int vector, int fd)
{
        struct eventfd_ctx *trigger;
        int irq_no, ret;

        if (vector < 0 || vector >= vdev->msi_count)
                return -EINVAL;

        irq_no = vdev->cdx_irqs[vector].irq_no;

        if (vdev->cdx_irqs[vector].trigger) {
                free_irq(irq_no, vdev->cdx_irqs[vector].trigger);
                kfree(vdev->cdx_irqs[vector].name);
                eventfd_ctx_put(vdev->cdx_irqs[vector].trigger);
                vdev->cdx_irqs[vector].trigger = NULL;
        }

        if (fd < 0)
                return 0;

        vdev->cdx_irqs[vector].name = kasprintf(GFP_KERNEL, "vfio-msi[%d](%s)",
                                                vector, dev_name(vdev->vdev.dev));
        if (!vdev->cdx_irqs[vector].name)
                return -ENOMEM;

        trigger = eventfd_ctx_fdget(fd);
        if (IS_ERR(trigger)) {
                kfree(vdev->cdx_irqs[vector].name);
                return PTR_ERR(trigger);
        }

        ret = request_irq(irq_no, vfio_cdx_msihandler, 0,
                          vdev->cdx_irqs[vector].name, trigger);
        if (ret) {
                kfree(vdev->cdx_irqs[vector].name);
                eventfd_ctx_put(trigger);
                return ret;
        }

        vdev->cdx_irqs[vector].trigger = trigger;

        return 0;
}

static int vfio_cdx_msi_set_block(struct vfio_cdx_device *vdev,
                                  unsigned int start, unsigned int count,
                                  int32_t *fds)
{
        int i, j, ret = 0;

        if (start >= vdev->msi_count || start + count > vdev->msi_count)
                return -EINVAL;

        for (i = 0, j = start; i < count && !ret; i++, j++) {
                int fd = fds ? fds[i] : -1;

                ret = vfio_cdx_msi_set_vector_signal(vdev, j, fd);
        }

        if (ret) {
                for (--j; j >= (int)start; j--)
                        vfio_cdx_msi_set_vector_signal(vdev, j, -1);
        }

        return ret;
}

static void vfio_cdx_msi_disable(struct vfio_cdx_device *vdev)
{
        struct cdx_device *cdx_dev = to_cdx_device(vdev->vdev.dev);
        struct device *dev = vdev->vdev.dev;

        vfio_cdx_msi_set_block(vdev, 0, vdev->msi_count, NULL);

        if (!vdev->config_msi)
                return;

        msi_domain_free_irqs_all(dev, MSI_DEFAULT_DOMAIN);
        cdx_disable_msi(cdx_dev);
        kfree(vdev->cdx_irqs);

        vdev->cdx_irqs = NULL;
        vdev->msi_count = 0;
        vdev->config_msi = 0;
}

static int vfio_cdx_set_msi_trigger(struct vfio_cdx_device *vdev,
                                    unsigned int index, unsigned int start,
                                    unsigned int count, u32 flags,
                                    void *data)
{
        struct cdx_device *cdx_dev = to_cdx_device(vdev->vdev.dev);
        int i;

        if (start + count > cdx_dev->num_msi)
                return -EINVAL;

        if (!count && (flags & VFIO_IRQ_SET_DATA_NONE)) {
                vfio_cdx_msi_disable(vdev);
                return 0;
        }

        if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
                s32 *fds = data;
                int ret;

                if (vdev->config_msi)
                        return vfio_cdx_msi_set_block(vdev, start, count,
                                                  fds);
                ret = vfio_cdx_msi_enable(vdev, cdx_dev->num_msi);
                if (ret)
                        return ret;

                ret = vfio_cdx_msi_set_block(vdev, start, count, fds);
                if (ret)
                        vfio_cdx_msi_disable(vdev);

                return ret;
        }

        for (i = start; i < start + count; i++) {
                if (!vdev->cdx_irqs[i].trigger)
                        continue;
                if (flags & VFIO_IRQ_SET_DATA_NONE) {
                        eventfd_signal(vdev->cdx_irqs[i].trigger);
                } else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
                        u8 *bools = data;

                        if (bools[i - start])
                                eventfd_signal(vdev->cdx_irqs[i].trigger);
                }
        }

        return 0;
}

int vfio_cdx_set_irqs_ioctl(struct vfio_cdx_device *vdev,
                            u32 flags, unsigned int index,
                            unsigned int start, unsigned int count,
                            void *data)
{
        if (flags & VFIO_IRQ_SET_ACTION_TRIGGER)
                return vfio_cdx_set_msi_trigger(vdev, index, start,
                          count, flags, data);
        else
                return -EINVAL;
}

/* Free All IRQs for the given device */
void vfio_cdx_irqs_cleanup(struct vfio_cdx_device *vdev)
{
        /*
         * Device does not support any interrupt or the interrupts
         * were not configured
         */
        if (!vdev->cdx_irqs)
                return;

        vfio_cdx_set_msi_trigger(vdev, 0, 0, 0, VFIO_IRQ_SET_DATA_NONE, NULL);
}