// SPDX-License-Identifier: GPL-2.0-or-later

#include "linux/virtio_pci.h"
#include <linux/virtio_pci_legacy.h>
#include <linux/module.h>
#include <linux/pci.h>


/*
 * vp_legacy_probe: probe the legacy virtio pci device, note that the
 * caller is required to enable PCI device before calling this function.
 * @ldev: the legacy virtio-pci device
 *
 * Return 0 on succeed otherwise fail
 */
int vp_legacy_probe(struct virtio_pci_legacy_device *ldev)
{
        struct pci_dev *pci_dev = ldev->pci_dev;
        int rc;

        /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
        if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
                return -ENODEV;

        if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION)
                return -ENODEV;

        rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
        if (rc) {
                rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32));
        } else {
                /*
                 * The virtio ring base address is expressed as a 32-bit PFN,
                 * with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT.
                 */
                dma_set_coherent_mask(&pci_dev->dev,
                                DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT));
        }

        if (rc)
                dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");

        rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy");
        if (rc)
                return rc;

        ldev->ioaddr = pci_iomap(pci_dev, 0, 0);
        if (!ldev->ioaddr) {
                rc = -EIO;
                goto err_iomap;
        }

        ldev->isr = ldev->ioaddr + VIRTIO_PCI_ISR;

        ldev->id.vendor = pci_dev->subsystem_vendor;
        ldev->id.device = pci_dev->subsystem_device;

        return 0;
err_iomap:
        pci_release_region(pci_dev, 0);
        return rc;
}
EXPORT_SYMBOL_GPL(vp_legacy_probe);

/*
 * vp_legacy_probe: remove and cleanup the legacy virtio pci device
 * @ldev: the legacy virtio-pci device
 */
void vp_legacy_remove(struct virtio_pci_legacy_device *ldev)
{
        struct pci_dev *pci_dev = ldev->pci_dev;

        pci_iounmap(pci_dev, ldev->ioaddr);
        pci_release_region(pci_dev, 0);
}
EXPORT_SYMBOL_GPL(vp_legacy_remove);

/*
 * vp_legacy_get_features - get features from device
 * @ldev: the legacy virtio-pci device
 *
 * Returns the features read from the device
 */
u64 vp_legacy_get_features(struct virtio_pci_legacy_device *ldev)
{

        return ioread32(ldev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
}
EXPORT_SYMBOL_GPL(vp_legacy_get_features);

/*
 * vp_legacy_get_driver_features - get driver features from device
 * @ldev: the legacy virtio-pci device
 *
 * Returns the driver features read from the device
 */
u64 vp_legacy_get_driver_features(struct virtio_pci_legacy_device *ldev)
{
        return ioread32(ldev->ioaddr + VIRTIO_PCI_GUEST_FEATURES);
}
EXPORT_SYMBOL_GPL(vp_legacy_get_driver_features);

/*
 * vp_legacy_set_features - set features to device
 * @ldev: the legacy virtio-pci device
 * @features: the features set to device
 */
void vp_legacy_set_features(struct virtio_pci_legacy_device *ldev,
                            u32 features)
{
        iowrite32(features, ldev->ioaddr + VIRTIO_PCI_GUEST_FEATURES);
}
EXPORT_SYMBOL_GPL(vp_legacy_set_features);

/*
 * vp_legacy_get_status - get the device status
 * @ldev: the legacy virtio-pci device
 *
 * Returns the status read from device
 */
u8 vp_legacy_get_status(struct virtio_pci_legacy_device *ldev)
{
        return ioread8(ldev->ioaddr + VIRTIO_PCI_STATUS);
}
EXPORT_SYMBOL_GPL(vp_legacy_get_status);

/*
 * vp_legacy_set_status - set status to device
 * @ldev: the legacy virtio-pci device
 * @status: the status set to device
 */
void vp_legacy_set_status(struct virtio_pci_legacy_device *ldev,
                                 u8 status)
{
        iowrite8(status, ldev->ioaddr + VIRTIO_PCI_STATUS);
}
EXPORT_SYMBOL_GPL(vp_legacy_set_status);

/*
 * vp_legacy_queue_vector - set the MSIX vector for a specific virtqueue
 * @ldev: the legacy virtio-pci device
 * @index: queue index
 * @vector: the queue vector
 *
 * Returns the queue vector read from the device
 */
u16 vp_legacy_queue_vector(struct virtio_pci_legacy_device *ldev,
                           u16 index, u16 vector)
{
        iowrite16(index, ldev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
        iowrite16(vector, ldev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
        /* Flush the write out to device */
        return ioread16(ldev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
}
EXPORT_SYMBOL_GPL(vp_legacy_queue_vector);

/*
 * vp_legacy_config_vector - set the vector for config interrupt
 * @ldev: the legacy virtio-pci device
 * @vector: the config vector
 *
 * Returns the config vector read from the device
 */
u16 vp_legacy_config_vector(struct virtio_pci_legacy_device *ldev,
                            u16 vector)
{
        /* Setup the vector used for configuration events */
        iowrite16(vector, ldev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR);
        /* Verify we had enough resources to assign the vector */
        /* Will also flush the write out to device */
        return ioread16(ldev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR);
}
EXPORT_SYMBOL_GPL(vp_legacy_config_vector);

/*
 * vp_legacy_set_queue_address - set the virtqueue address
 * @ldev: the legacy virtio-pci device
 * @index: the queue index
 * @queue_pfn: pfn of the virtqueue
 */
void vp_legacy_set_queue_address(struct virtio_pci_legacy_device *ldev,
                             u16 index, u32 queue_pfn)
{
        iowrite16(index, ldev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
        iowrite32(queue_pfn, ldev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
}
EXPORT_SYMBOL_GPL(vp_legacy_set_queue_address);

/*
 * vp_legacy_get_queue_enable - enable a virtqueue
 * @ldev: the legacy virtio-pci device
 * @index: the queue index
 *
 * Returns whether a virtqueue is enabled or not
 */
bool vp_legacy_get_queue_enable(struct virtio_pci_legacy_device *ldev,
                                u16 index)
{
        iowrite16(index, ldev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
        return ioread32(ldev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
}
EXPORT_SYMBOL_GPL(vp_legacy_get_queue_enable);

/*
 * vp_legacy_get_queue_size - get size for a virtqueue
 * @ldev: the legacy virtio-pci device
 * @index: the queue index
 *
 * Returns the size of the virtqueue
 */
u16 vp_legacy_get_queue_size(struct virtio_pci_legacy_device *ldev,
                             u16 index)
{
        iowrite16(index, ldev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
        return ioread16(ldev->ioaddr + VIRTIO_PCI_QUEUE_NUM);
}
EXPORT_SYMBOL_GPL(vp_legacy_get_queue_size);

MODULE_VERSION("0.1");
MODULE_DESCRIPTION("Legacy Virtio PCI Device");
MODULE_AUTHOR("Wu Zongyong <wuzongyong@linux.alibaba.com>");
MODULE_LICENSE("GPL");