// SPDX-License-Identifier: GPL-2.0-only
/*
 * vDPA bridge driver for Alibaba ENI(Elastic Network Interface)
 *
 * Copyright (c) 2021, Alibaba Inc. All rights reserved.
 * Author: Wu Zongyong <wuzongyong@linux.alibaba.com>
 *
 */

#include "linux/bits.h"
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/vdpa.h>
#include <linux/virtio.h>
#include <linux/virtio_config.h>
#include <linux/virtio_ring.h>
#include <linux/virtio_pci.h>
#include <linux/virtio_pci_legacy.h>
#include <uapi/linux/virtio_net.h>

#define ENI_MSIX_NAME_SIZE 256

#define ENI_ERR(pdev, fmt, ...) \
        dev_err(&pdev->dev, "%s"fmt, "eni_vdpa: ", ##__VA_ARGS__)
#define ENI_DBG(pdev, fmt, ...) \
        dev_dbg(&pdev->dev, "%s"fmt, "eni_vdpa: ", ##__VA_ARGS__)
#define ENI_INFO(pdev, fmt, ...) \
        dev_info(&pdev->dev, "%s"fmt, "eni_vdpa: ", ##__VA_ARGS__)

struct eni_vring {
        void __iomem *notify;
        char msix_name[ENI_MSIX_NAME_SIZE];
        struct vdpa_callback cb;
        int irq;
};

struct eni_vdpa {
        struct vdpa_device vdpa;
        struct virtio_pci_legacy_device ldev;
        struct eni_vring *vring;
        struct vdpa_callback config_cb;
        char msix_name[ENI_MSIX_NAME_SIZE];
        int config_irq;
        int queues;
        int vectors;
};

static struct eni_vdpa *vdpa_to_eni(struct vdpa_device *vdpa)
{
        return container_of(vdpa, struct eni_vdpa, vdpa);
}

static struct virtio_pci_legacy_device *vdpa_to_ldev(struct vdpa_device *vdpa)
{
        struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);

        return &eni_vdpa->ldev;
}

static u64 eni_vdpa_get_device_features(struct vdpa_device *vdpa)
{
        struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
        u64 features = vp_legacy_get_features(ldev);

        features |= BIT_ULL(VIRTIO_F_ACCESS_PLATFORM);
        features |= BIT_ULL(VIRTIO_F_ORDER_PLATFORM);

        return features;
}

static int eni_vdpa_set_driver_features(struct vdpa_device *vdpa, u64 features)
{
        struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);

        if (!(features & BIT_ULL(VIRTIO_NET_F_MRG_RXBUF)) && features) {
                ENI_ERR(ldev->pci_dev,
                        "VIRTIO_NET_F_MRG_RXBUF is not negotiated\n");
                return -EINVAL;
        }

        vp_legacy_set_features(ldev, (u32)features);

        return 0;
}

static u64 eni_vdpa_get_driver_features(struct vdpa_device *vdpa)
{
        struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);

        return vp_legacy_get_driver_features(ldev);
}

static u8 eni_vdpa_get_status(struct vdpa_device *vdpa)
{
        struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);

        return vp_legacy_get_status(ldev);
}

static int eni_vdpa_get_vq_irq(struct vdpa_device *vdpa, u16 idx)
{
        struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);
        int irq = eni_vdpa->vring[idx].irq;

        if (irq == VIRTIO_MSI_NO_VECTOR)
                return -EINVAL;

        return irq;
}

static void eni_vdpa_free_irq(struct eni_vdpa *eni_vdpa)
{
        struct virtio_pci_legacy_device *ldev = &eni_vdpa->ldev;
        struct pci_dev *pdev = ldev->pci_dev;
        int i;

        for (i = 0; i < eni_vdpa->queues; i++) {
                if (eni_vdpa->vring[i].irq != VIRTIO_MSI_NO_VECTOR) {
                        vp_legacy_queue_vector(ldev, i, VIRTIO_MSI_NO_VECTOR);
                        devm_free_irq(&pdev->dev, eni_vdpa->vring[i].irq,
                                      &eni_vdpa->vring[i]);
                        eni_vdpa->vring[i].irq = VIRTIO_MSI_NO_VECTOR;
                }
        }

        if (eni_vdpa->config_irq != VIRTIO_MSI_NO_VECTOR) {
                vp_legacy_config_vector(ldev, VIRTIO_MSI_NO_VECTOR);
                devm_free_irq(&pdev->dev, eni_vdpa->config_irq, eni_vdpa);
                eni_vdpa->config_irq = VIRTIO_MSI_NO_VECTOR;
        }

        if (eni_vdpa->vectors) {
                pci_free_irq_vectors(pdev);
                eni_vdpa->vectors = 0;
        }
}

static irqreturn_t eni_vdpa_vq_handler(int irq, void *arg)
{
        struct eni_vring *vring = arg;

        if (vring->cb.callback)
                return vring->cb.callback(vring->cb.private);

        return IRQ_HANDLED;
}

static irqreturn_t eni_vdpa_config_handler(int irq, void *arg)
{
        struct eni_vdpa *eni_vdpa = arg;

        if (eni_vdpa->config_cb.callback)
                return eni_vdpa->config_cb.callback(eni_vdpa->config_cb.private);

        return IRQ_HANDLED;
}

static int eni_vdpa_request_irq(struct eni_vdpa *eni_vdpa)
{
        struct virtio_pci_legacy_device *ldev = &eni_vdpa->ldev;
        struct pci_dev *pdev = ldev->pci_dev;
        int i, ret, irq;
        int queues = eni_vdpa->queues;
        int vectors = queues + 1;

        ret = pci_alloc_irq_vectors(pdev, vectors, vectors, PCI_IRQ_MSIX);
        if (ret != vectors) {
                ENI_ERR(pdev,
                        "failed to allocate irq vectors want %d but %d\n",
                        vectors, ret);
                return ret;
        }

        eni_vdpa->vectors = vectors;

        for (i = 0; i < queues; i++) {
                snprintf(eni_vdpa->vring[i].msix_name, ENI_MSIX_NAME_SIZE,
                         "eni-vdpa[%s]-%d\n", pci_name(pdev), i);
                irq = pci_irq_vector(pdev, i);
                ret = devm_request_irq(&pdev->dev, irq,
                                       eni_vdpa_vq_handler,
                                       0, eni_vdpa->vring[i].msix_name,
                                       &eni_vdpa->vring[i]);
                if (ret) {
                        ENI_ERR(pdev, "failed to request irq for vq %d\n", i);
                        goto err;
                }
                vp_legacy_queue_vector(ldev, i, i);
                eni_vdpa->vring[i].irq = irq;
        }

        snprintf(eni_vdpa->msix_name, ENI_MSIX_NAME_SIZE, "eni-vdpa[%s]-config\n",
                 pci_name(pdev));
        irq = pci_irq_vector(pdev, queues);
        ret = devm_request_irq(&pdev->dev, irq, eni_vdpa_config_handler, 0,
                               eni_vdpa->msix_name, eni_vdpa);
        if (ret) {
                ENI_ERR(pdev, "failed to request irq for config vq %d\n", i);
                goto err;
        }
        vp_legacy_config_vector(ldev, queues);
        eni_vdpa->config_irq = irq;

        return 0;
err:
        eni_vdpa_free_irq(eni_vdpa);
        return ret;
}

static void eni_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
{
        struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);
        struct virtio_pci_legacy_device *ldev = &eni_vdpa->ldev;
        u8 s = eni_vdpa_get_status(vdpa);

        if (status & VIRTIO_CONFIG_S_DRIVER_OK &&
            !(s & VIRTIO_CONFIG_S_DRIVER_OK)) {
                eni_vdpa_request_irq(eni_vdpa);
        }

        vp_legacy_set_status(ldev, status);

        if (!(status & VIRTIO_CONFIG_S_DRIVER_OK) &&
            (s & VIRTIO_CONFIG_S_DRIVER_OK))
                eni_vdpa_free_irq(eni_vdpa);
}

static int eni_vdpa_reset(struct vdpa_device *vdpa)
{
        struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);
        struct virtio_pci_legacy_device *ldev = &eni_vdpa->ldev;
        u8 s = eni_vdpa_get_status(vdpa);

        vp_legacy_set_status(ldev, 0);

        if (s & VIRTIO_CONFIG_S_DRIVER_OK)
                eni_vdpa_free_irq(eni_vdpa);

        return 0;
}

static u16 eni_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
{
        struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);

        return vp_legacy_get_queue_size(ldev, 0);
}

static u16 eni_vdpa_get_vq_num_min(struct vdpa_device *vdpa)
{
        struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);

        return vp_legacy_get_queue_size(ldev, 0);
}

static u16 eni_vdpa_get_vq_size(struct vdpa_device *vdpa, u16 qid)
{
        struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);

        return vp_legacy_get_queue_size(ldev, qid);
}

static int eni_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid,
                                struct vdpa_vq_state *state)
{
        return -EOPNOTSUPP;
}

static int eni_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 qid,
                                 const struct vdpa_vq_state *state)
{
        struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
        const struct vdpa_vq_state_split *split = &state->split;

        /* ENI is build upon virtio-pci specfication which not support
         * to set state of virtqueue. But if the state is equal to the
         * device initial state by chance, we can let it go.
         */
        if (!vp_legacy_get_queue_enable(ldev, qid)
            && split->avail_index == 0)
                return 0;

        return -EOPNOTSUPP;
}


static void eni_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 qid,
                               struct vdpa_callback *cb)
{
        struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);

        eni_vdpa->vring[qid].cb = *cb;
}

static void eni_vdpa_set_vq_ready(struct vdpa_device *vdpa, u16 qid,
                                  bool ready)
{
        struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);

        /* ENI is a legacy virtio-pci device. This is not supported
         * by specification. But we can disable virtqueue by setting
         * address to 0.
         */
        if (!ready)
                vp_legacy_set_queue_address(ldev, qid, 0);
}

static bool eni_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 qid)
{
        struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);

        return vp_legacy_get_queue_enable(ldev, qid);
}

static void eni_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 qid,
                               u32 num)
{
        struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
        struct pci_dev *pdev = ldev->pci_dev;
        u16 n = vp_legacy_get_queue_size(ldev, qid);

        /* ENI is a legacy virtio-pci device which not allow to change
         * virtqueue size. Just report a error if someone tries to
         * change it.
         */
        if (num != n)
                ENI_ERR(pdev,
                        "not support to set vq %u fixed num %u to %u\n",
                        qid, n, num);
}

static int eni_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 qid,
                                   u64 desc_area, u64 driver_area,
                                   u64 device_area)
{
        struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
        u32 pfn = desc_area >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;

        vp_legacy_set_queue_address(ldev, qid, pfn);

        return 0;
}

static void eni_vdpa_kick_vq(struct vdpa_device *vdpa, u16 qid)
{
        struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);

        iowrite16(qid, eni_vdpa->vring[qid].notify);
}

static u32 eni_vdpa_get_device_id(struct vdpa_device *vdpa)
{
        struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);

        return ldev->id.device;
}

static u32 eni_vdpa_get_vendor_id(struct vdpa_device *vdpa)
{
        struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);

        return ldev->id.vendor;
}

static u32 eni_vdpa_get_vq_align(struct vdpa_device *vdpa)
{
        return VIRTIO_PCI_VRING_ALIGN;
}

static size_t eni_vdpa_get_config_size(struct vdpa_device *vdpa)
{
        return sizeof(struct virtio_net_config);
}


static void eni_vdpa_get_config(struct vdpa_device *vdpa,
                                unsigned int offset,
                                void *buf, unsigned int len)
{
        struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);
        struct virtio_pci_legacy_device *ldev = &eni_vdpa->ldev;
        void __iomem *ioaddr = ldev->ioaddr +
                VIRTIO_PCI_CONFIG_OFF(eni_vdpa->vectors) +
                offset;
        u8 *p = buf;
        int i;

        for (i = 0; i < len; i++)
                *p++ = ioread8(ioaddr + i);
}

static void eni_vdpa_set_config(struct vdpa_device *vdpa,
                                unsigned int offset, const void *buf,
                                unsigned int len)
{
        struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);
        struct virtio_pci_legacy_device *ldev = &eni_vdpa->ldev;
        void __iomem *ioaddr = ldev->ioaddr +
                VIRTIO_PCI_CONFIG_OFF(eni_vdpa->vectors) +
                offset;
        const u8 *p = buf;
        int i;

        for (i = 0; i < len; i++)
                iowrite8(*p++, ioaddr + i);
}

static void eni_vdpa_set_config_cb(struct vdpa_device *vdpa,
                                   struct vdpa_callback *cb)
{
        struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);

        eni_vdpa->config_cb = *cb;
}

static const struct vdpa_config_ops eni_vdpa_ops = {
        .get_device_features = eni_vdpa_get_device_features,
        .set_driver_features = eni_vdpa_set_driver_features,
        .get_driver_features = eni_vdpa_get_driver_features,
        .get_status     = eni_vdpa_get_status,
        .set_status     = eni_vdpa_set_status,
        .reset          = eni_vdpa_reset,
        .get_vq_num_max = eni_vdpa_get_vq_num_max,
        .get_vq_num_min = eni_vdpa_get_vq_num_min,
        .get_vq_size    = eni_vdpa_get_vq_size,
        .get_vq_state   = eni_vdpa_get_vq_state,
        .set_vq_state   = eni_vdpa_set_vq_state,
        .set_vq_cb      = eni_vdpa_set_vq_cb,
        .set_vq_ready   = eni_vdpa_set_vq_ready,
        .get_vq_ready   = eni_vdpa_get_vq_ready,
        .set_vq_num     = eni_vdpa_set_vq_num,
        .set_vq_address = eni_vdpa_set_vq_address,
        .kick_vq        = eni_vdpa_kick_vq,
        .get_device_id  = eni_vdpa_get_device_id,
        .get_vendor_id  = eni_vdpa_get_vendor_id,
        .get_vq_align   = eni_vdpa_get_vq_align,
        .get_config_size = eni_vdpa_get_config_size,
        .get_config     = eni_vdpa_get_config,
        .set_config     = eni_vdpa_set_config,
        .set_config_cb  = eni_vdpa_set_config_cb,
        .get_vq_irq     = eni_vdpa_get_vq_irq,
};


static u16 eni_vdpa_get_num_queues(struct eni_vdpa *eni_vdpa)
{
        struct virtio_pci_legacy_device *ldev = &eni_vdpa->ldev;
        u32 features = vp_legacy_get_features(ldev);
        u16 num = 2;

        if (features & BIT_ULL(VIRTIO_NET_F_MQ)) {
                __virtio16 max_virtqueue_pairs;

                eni_vdpa_get_config(&eni_vdpa->vdpa,
                        offsetof(struct virtio_net_config, max_virtqueue_pairs),
                        &max_virtqueue_pairs,
                        sizeof(max_virtqueue_pairs));
                num = 2 * __virtio16_to_cpu(virtio_legacy_is_little_endian(),
                                max_virtqueue_pairs);
        }

        if (features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ))
                num += 1;

        return num;
}

static int eni_vdpa_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
        struct device *dev = &pdev->dev;
        struct eni_vdpa *eni_vdpa;
        struct virtio_pci_legacy_device *ldev;
        int ret, i;

        ret = pcim_enable_device(pdev);
        if (ret)
                return ret;

        eni_vdpa = vdpa_alloc_device(struct eni_vdpa, vdpa,
                                     dev, &eni_vdpa_ops, NULL,
                                     1, 1, NULL, false);
        if (IS_ERR(eni_vdpa)) {
                ENI_ERR(pdev, "failed to allocate vDPA structure\n");
                return PTR_ERR(eni_vdpa);
        }

        ldev = &eni_vdpa->ldev;
        ldev->pci_dev = pdev;

        ret = vp_legacy_probe(ldev);
        if (ret) {
                ENI_ERR(pdev, "failed to probe legacy PCI device\n");
                goto err;
        }

        pci_set_master(pdev);
        pci_set_drvdata(pdev, eni_vdpa);

        eni_vdpa->vdpa.vmap.dma_dev = &pdev->dev;
        eni_vdpa->queues = eni_vdpa_get_num_queues(eni_vdpa);

        eni_vdpa->vring = devm_kcalloc(&pdev->dev, eni_vdpa->queues,
                                      sizeof(*eni_vdpa->vring),
                                      GFP_KERNEL);
        if (!eni_vdpa->vring) {
                ret = -ENOMEM;
                ENI_ERR(pdev, "failed to allocate virtqueues\n");
                goto err_remove_vp_legacy;
        }

        for (i = 0; i < eni_vdpa->queues; i++) {
                eni_vdpa->vring[i].irq = VIRTIO_MSI_NO_VECTOR;
                eni_vdpa->vring[i].notify = ldev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
        }
        eni_vdpa->config_irq = VIRTIO_MSI_NO_VECTOR;

        ret = vdpa_register_device(&eni_vdpa->vdpa, eni_vdpa->queues);
        if (ret) {
                ENI_ERR(pdev, "failed to register to vdpa bus\n");
                goto err_remove_vp_legacy;
        }

        return 0;

err_remove_vp_legacy:
        vp_legacy_remove(&eni_vdpa->ldev);
err:
        put_device(&eni_vdpa->vdpa.dev);
        return ret;
}

static void eni_vdpa_remove(struct pci_dev *pdev)
{
        struct eni_vdpa *eni_vdpa = pci_get_drvdata(pdev);

        vdpa_unregister_device(&eni_vdpa->vdpa);
        vp_legacy_remove(&eni_vdpa->ldev);
}

static struct pci_device_id eni_pci_ids[] = {
        { PCI_DEVICE_SUB(PCI_VENDOR_ID_REDHAT_QUMRANET,
                         VIRTIO_TRANS_ID_NET,
                         PCI_SUBVENDOR_ID_REDHAT_QUMRANET,
                         VIRTIO_ID_NET) },
        { 0 },
};

static struct pci_driver eni_vdpa_driver = {
        .name           = "alibaba-eni-vdpa",
        .id_table       = eni_pci_ids,
        .probe          = eni_vdpa_probe,
        .remove         = eni_vdpa_remove,
};

module_pci_driver(eni_vdpa_driver);

MODULE_AUTHOR("Wu Zongyong <wuzongyong@linux.alibaba.com>");
MODULE_DESCRIPTION("Alibaba ENI vDPA driver");
MODULE_LICENSE("GPL v2");