/*
 * Copyright 2021, Haiku, Inc.
 * Distributed under the terms of the MIT License.
 */


#ifndef _VIRTIO_H_
#define _VIRTIO_H_


#include <virtio_defs.h>
#include <util/DoublyLinkedList.h>


struct VirtioResources {
        VirtioRegs* volatile regs;
        size_t regsSize;
        int32_t irq;
};

enum IOState {
        ioStateInactive,
        ioStatePending,
        ioStateDone,
        ioStateFailed,
};

enum IOOperation {
        ioOpRead,
        ioOpWrite,
};

struct IORequest {
        IOState state;
        IOOperation op;
        void* buf;
        size_t len;
        IORequest* next;

        IORequest(IOOperation op, void* buf, size_t len): state(ioStateInactive),
                op(op), buf(buf), len(len), next(NULL) {}
};

class VirtioDevice : public DoublyLinkedListLinkImpl<VirtioDevice> {
private:
        VirtioRegs* volatile fRegs;
        size_t fQueueLen;
        VirtioDesc* volatile fDescs;
        VirtioAvail* volatile fAvail;
        VirtioUsed* volatile fUsed;
        uint32_t* fFreeDescs;
        uint32_t fLastUsed;
        IORequest** fReqs;

        int32_t AllocDesc();
        void FreeDesc(int32_t idx);

public:
        VirtioDevice(const VirtioResources& devRes);
        ~VirtioDevice();
        inline VirtioRegs* volatile Regs() {return fRegs;}
        void ScheduleIO(IORequest** reqs, uint32 cnt);
        void ScheduleIO(IORequest* req);
        IORequest* ConsumeIO();
        IORequest* WaitIO();
};


void virtio_init();
void virtio_fini();
void virtio_register(addr_t base, size_t len, uint32 irq);

VirtioResources* ThisVirtioDev(uint32 deviceId, int n);

int virtio_input_get_key();
int virtio_input_wait_for_key();

#endif  // _VIRTIO_H_