// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
 *
 * VirtIO Sandbox transport driver, for testing purpose only
 */

#include <common.h>
#include <dm.h>
#include <virtio_types.h>
#include <virtio.h>
#include <virtio_ring.h>
#include <linux/bug.h>
#include <linux/compat.h>
#include <linux/err.h>
#include <linux/io.h>

struct virtio_sandbox_priv {
        u8 id;
        u8 status;
        u64 device_features;
        u64 driver_features;
        ulong queue_desc;
        ulong queue_available;
        ulong queue_used;
};

static int virtio_sandbox_get_config(struct udevice *udev, unsigned int offset,
                                     void *buf, unsigned int len)
{
        return 0;
}

static int virtio_sandbox_set_config(struct udevice *udev, unsigned int offset,
                                     const void *buf, unsigned int len)
{
        return 0;
}

static int virtio_sandbox_get_status(struct udevice *udev, u8 *status)
{
        struct virtio_sandbox_priv *priv = dev_get_priv(udev);

        *status = priv->status;

        return 0;
}

static int virtio_sandbox_set_status(struct udevice *udev, u8 status)
{
        struct virtio_sandbox_priv *priv = dev_get_priv(udev);

        /* We should never be setting status to 0 */
        WARN_ON(status == 0);

        priv->status = status;

        return 0;
}

static int virtio_sandbox_reset(struct udevice *udev)
{
        struct virtio_sandbox_priv *priv = dev_get_priv(udev);

        /* 0 status means a reset */
        priv->status = 0;

        return 0;
}

static int virtio_sandbox_get_features(struct udevice *udev, u64 *features)
{
        struct virtio_sandbox_priv *priv = dev_get_priv(udev);

        *features = priv->device_features;

        return 0;
}

static int virtio_sandbox_set_features(struct udevice *udev)
{
        struct virtio_sandbox_priv *priv = dev_get_priv(udev);
        struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);

        priv->driver_features = uc_priv->features;

        return 0;
}

static struct virtqueue *virtio_sandbox_setup_vq(struct udevice *udev,
                                                 unsigned int index)
{
        struct virtio_sandbox_priv *priv = dev_get_priv(udev);
        struct virtqueue *vq;
        ulong addr;
        int err;

        /* Create the vring */
        vq = vring_create_virtqueue(index, 4, 4096, udev);
        if (!vq) {
                err = -ENOMEM;
                goto error_new_virtqueue;
        }

        addr = virtqueue_get_desc_addr(vq);
        priv->queue_desc = addr;

        addr = virtqueue_get_avail_addr(vq);
        priv->queue_available = addr;

        addr = virtqueue_get_used_addr(vq);
        priv->queue_used = addr;

        return vq;

error_new_virtqueue:
        return ERR_PTR(err);
}

static void virtio_sandbox_del_vq(struct virtqueue *vq)
{
        vring_del_virtqueue(vq);
}

static int virtio_sandbox_del_vqs(struct udevice *udev)
{
        struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);
        struct virtqueue *vq, *n;

        list_for_each_entry_safe(vq, n, &uc_priv->vqs, list)
                virtio_sandbox_del_vq(vq);

        return 0;
}

static int virtio_sandbox_find_vqs(struct udevice *udev, unsigned int nvqs,
                                   struct virtqueue *vqs[])
{
        int i;

        for (i = 0; i < nvqs; ++i) {
                vqs[i] = virtio_sandbox_setup_vq(udev, i);
                if (IS_ERR(vqs[i])) {
                        virtio_sandbox_del_vqs(udev);
                        return PTR_ERR(vqs[i]);
                }
        }

        return 0;
}

static int virtio_sandbox_notify(struct udevice *udev, struct virtqueue *vq)
{
        return 0;
}

static int virtio_sandbox_probe(struct udevice *udev)
{
        struct virtio_sandbox_priv *priv = dev_get_priv(udev);
        struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);

        /* fake some information for testing */
        priv->device_features = VIRTIO_F_VERSION_1;
        uc_priv->device = VIRTIO_ID_BLOCK;
        uc_priv->vendor = ('u' << 24) | ('b' << 16) | ('o' << 8) | 't';

        return 0;
}

/* check virtio device driver's remove routine was called to reset the device */
static int virtio_sandbox_child_post_remove(struct udevice *vdev)
{
        u8 status;

        virtio_get_status(vdev, &status);
        if (status)
                panic("virtio device was not reset\n");

        return 0;
}

static const struct dm_virtio_ops virtio_sandbox1_ops = {
        .get_config     = virtio_sandbox_get_config,
        .set_config     = virtio_sandbox_set_config,
        .get_status     = virtio_sandbox_get_status,
        .set_status     = virtio_sandbox_set_status,
        .reset          = virtio_sandbox_reset,
        .get_features   = virtio_sandbox_get_features,
        .set_features   = virtio_sandbox_set_features,
        .find_vqs       = virtio_sandbox_find_vqs,
        .del_vqs        = virtio_sandbox_del_vqs,
        .notify         = virtio_sandbox_notify,
};

static const struct udevice_id virtio_sandbox1_ids[] = {
        { .compatible = "sandbox,virtio1" },
        { }
};

U_BOOT_DRIVER(virtio_sandbox1) = {
        .name   = "virtio-sandbox1",
        .id     = UCLASS_VIRTIO,
        .of_match = virtio_sandbox1_ids,
        .ops    = &virtio_sandbox1_ops,
        .probe  = virtio_sandbox_probe,
        .child_post_remove = virtio_sandbox_child_post_remove,
        .priv_auto      = sizeof(struct virtio_sandbox_priv),
};

/* this one without notify op */
static const struct dm_virtio_ops virtio_sandbox2_ops = {
        .get_config     = virtio_sandbox_get_config,
        .set_config     = virtio_sandbox_set_config,
        .get_status     = virtio_sandbox_get_status,
        .set_status     = virtio_sandbox_set_status,
        .reset          = virtio_sandbox_reset,
        .get_features   = virtio_sandbox_get_features,
        .set_features   = virtio_sandbox_set_features,
        .find_vqs       = virtio_sandbox_find_vqs,
        .del_vqs        = virtio_sandbox_del_vqs,
};

static const struct udevice_id virtio_sandbox2_ids[] = {
        { .compatible = "sandbox,virtio2" },
        { }
};

U_BOOT_DRIVER(virtio_sandbox2) = {
        .name   = "virtio-sandbox2",
        .id     = UCLASS_VIRTIO,
        .of_match = virtio_sandbox2_ids,
        .ops    = &virtio_sandbox2_ops,
        .probe  = virtio_sandbox_probe,
        .priv_auto      = sizeof(struct virtio_sandbox_priv),
};