// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2013 - Virtual Open Systems
 * Author: Antonios Motakis <a.motakis@virtualopensystems.com>
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/vfio.h>
#include <linux/pm_runtime.h>
#include <linux/amba/bus.h>

#include "vfio_platform_private.h"

#define DRIVER_VERSION  "0.10"
#define DRIVER_AUTHOR   "Antonios Motakis <a.motakis@virtualopensystems.com>"
#define DRIVER_DESC     "VFIO for AMBA devices - User Level meta-driver"

/* probing devices from the AMBA bus */

static struct resource *get_amba_resource(struct vfio_platform_device *vdev,
                                          int i)
{
        struct amba_device *adev = (struct amba_device *) vdev->opaque;

        if (i == 0)
                return &adev->res;

        return NULL;
}

static int get_amba_irq(struct vfio_platform_device *vdev, int i)
{
        struct amba_device *adev = (struct amba_device *) vdev->opaque;
        int ret = 0;

        if (i < AMBA_NR_IRQS)
                ret = adev->irq[i];

        /* zero is an unset IRQ for AMBA devices */
        return ret ? ret : -ENXIO;
}

static int vfio_amba_init_dev(struct vfio_device *core_vdev)
{
        struct vfio_platform_device *vdev =
                container_of(core_vdev, struct vfio_platform_device, vdev);
        struct amba_device *adev = to_amba_device(core_vdev->dev);
        int ret;

        vdev->name = kasprintf(GFP_KERNEL, "vfio-amba-%08x", adev->periphid);
        if (!vdev->name)
                return -ENOMEM;

        vdev->opaque = (void *) adev;
        vdev->flags = VFIO_DEVICE_FLAGS_AMBA;
        vdev->get_resource = get_amba_resource;
        vdev->get_irq = get_amba_irq;
        vdev->reset_required = false;

        ret = vfio_platform_init_common(vdev);
        if (ret)
                kfree(vdev->name);
        return ret;
}

static const struct vfio_device_ops vfio_amba_ops;
static int vfio_amba_probe(struct amba_device *adev, const struct amba_id *id)
{
        struct vfio_platform_device *vdev;
        int ret;

        dev_err_once(&adev->dev, "DEPRECATION: vfio-amba is deprecated and will be removed in a future kernel release\n");

        vdev = vfio_alloc_device(vfio_platform_device, vdev, &adev->dev,
                                 &vfio_amba_ops);
        if (IS_ERR(vdev))
                return PTR_ERR(vdev);

        ret = vfio_register_group_dev(&vdev->vdev);
        if (ret)
                goto out_put_vdev;

        pm_runtime_enable(&adev->dev);
        dev_set_drvdata(&adev->dev, vdev);
        return 0;

out_put_vdev:
        vfio_put_device(&vdev->vdev);
        return ret;
}

static void vfio_amba_release_dev(struct vfio_device *core_vdev)
{
        struct vfio_platform_device *vdev =
                container_of(core_vdev, struct vfio_platform_device, vdev);

        vfio_platform_release_common(vdev);
        kfree(vdev->name);
}

static void vfio_amba_remove(struct amba_device *adev)
{
        struct vfio_platform_device *vdev = dev_get_drvdata(&adev->dev);

        vfio_unregister_group_dev(&vdev->vdev);
        pm_runtime_disable(vdev->device);
        vfio_put_device(&vdev->vdev);
}

static const struct vfio_device_ops vfio_amba_ops = {
        .name           = "vfio-amba",
        .init           = vfio_amba_init_dev,
        .release        = vfio_amba_release_dev,
        .open_device    = vfio_platform_open_device,
        .close_device   = vfio_platform_close_device,
        .ioctl          = vfio_platform_ioctl,
        .get_region_info_caps = vfio_platform_ioctl_get_region_info,
        .read           = vfio_platform_read,
        .write          = vfio_platform_write,
        .mmap           = vfio_platform_mmap,
        .bind_iommufd   = vfio_iommufd_physical_bind,
        .unbind_iommufd = vfio_iommufd_physical_unbind,
        .attach_ioas    = vfio_iommufd_physical_attach_ioas,
        .detach_ioas    = vfio_iommufd_physical_detach_ioas,
};

static const struct amba_id vfio_amba_ids[] = {
        { 0, 0 },
};

MODULE_DEVICE_TABLE(amba, vfio_amba_ids);

static struct amba_driver vfio_amba_driver = {
        .probe = vfio_amba_probe,
        .remove = vfio_amba_remove,
        .id_table = vfio_amba_ids,
        .drv = {
                .name = "vfio-amba",
        },
        .driver_managed_dma = true,
};

module_amba_driver(vfio_amba_driver);

MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);