system/ulib/machina/include/machina/virtio_pci.h

// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#pragma once

#include <machina/pci.h>
#include <virtio/virtio.h>
#include <zircon/types.h>

class VirtioDevice;

typedef struct virtio_queue virtio_queue_t;

static const size_t kVirtioPciNumCapabilities = 4;

/* Virtio PCI transport implementation. */
class VirtioPci : public PciDevice {
public:
    VirtioPci(VirtioDevice* device);

    // Read a value at |bar| and |offset| from this device.
    zx_status_t ReadBar(uint8_t bar, uint64_t offset, IoValue* value) const override;
    // Write a value at |bar| and |offset| to this device.
    zx_status_t WriteBar(uint8_t bar, uint64_t offset, const IoValue& value) override;

private:
    // Handle accesses to the general configuration BAR.
    zx_status_t ConfigBarRead(uint64_t addr, IoValue* value) const;
    zx_status_t ConfigBarWrite(uint64_t addr, const IoValue& value);

    // Handle accesses to the common configuration region.
    zx_status_t CommonCfgRead(uint64_t addr, IoValue* value) const;
    zx_status_t CommonCfgWrite(uint64_t addr, const IoValue& value);

    // Handle writes to the notify BAR.
    zx_status_t NotifyBarWrite(uint64_t addr, const IoValue& value);

    void SetupCaps();
    void SetupCap(pci_cap_t* cap, virtio_pci_cap_t* virtio_cap, uint8_t cfg_type,
                  size_t cap_len, size_t data_length, uint8_t bar, size_t bar_offset);

    virtio_queue_t* selected_queue() const;

    // We need one of these for every virtio_pci_cap_t structure we expose.
    pci_cap_t capabilities_[kVirtioPciNumCapabilities];
    // Virtio PCI capabilities.
    virtio_pci_cap_t common_cfg_cap_;
    virtio_pci_cap_t device_cfg_cap_;
    virtio_pci_notify_cap_t notify_cfg_cap_;
    virtio_pci_cap_t isr_cfg_cap_;

    VirtioDevice* device_;
};