ardupilot/libraries/AP_HAL_Linux/CAN.h

/* This code was taken from UAVCAN project, which uses The MIT License (MIT).

   Copyright (c) 2014 Pavel Kirienko

   Permission is hereby granted, free of charge, to any person obtaining a copy of
   this software and associated documentation files (the "Software"), to deal in
   the Software without restriction, including without limitation the rights to
   use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
   the Software, and to permit persons to whom the Software is furnished to do so,
   subject to the following conditions:

   The above copyright notice and this permission notice shall be included in all
   copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
   FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
   COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
   IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/* This code was modified to use with ArduPilot project, which uses GPL license.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include "AP_HAL_Linux.h"
#include <AP_HAL/CAN.h>

#include <linux/can.h>

#include <string>
#include <queue>
#include <memory>
#include <map>
#include <unordered_set>
#include <poll.h>

namespace Linux {

enum class SocketCanError
{
    SocketReadFailure,
    SocketWriteFailure,
    TxTimeout
};

#define CAN_MAX_POLL_ITERATIONS_COUNT 100
#define CAN_MAX_INIT_TRIES_COUNT 100
#define CAN_FILTER_NUMBER 8

class CAN: public AP_HAL::CAN {
public:
    CAN(int socket_fd=0)
      : _fd(socket_fd)
      , _frames_in_socket_tx_queue(0)
      , _max_frames_in_socket_tx_queue(2)
    { }
    ~CAN() { }

    bool begin(uint32_t bitrate) override;

    void end() override;

    void reset() override;

    bool is_initialized() override;
    
    int32_t tx_pending() override;

    int32_t available() override;

    static int openSocket(const std::string& iface_name);

    int getFileDescriptor() const { return _fd; }

    int16_t send(const uavcan::CanFrame& frame, uavcan::MonotonicTime tx_deadline,
                     uavcan::CanIOFlags flags) override;

    int16_t receive(uavcan::CanFrame& out_frame, uavcan::MonotonicTime& out_ts_monotonic,
                        uavcan::UtcTime& out_ts_utc, uavcan::CanIOFlags& out_flags) override;

    bool hasReadyTx() const;

    bool hasReadyRx() const;

    void poll(bool read, bool write);

    int16_t configureFilters(const uavcan::CanFilterConfig* filter_configs, uint16_t num_configs) override;

    uint16_t getNumFilters() const override;

    uint64_t getErrorCount() const override;


private:
    struct TxItem
    {
        uavcan::CanFrame frame;
        uavcan::MonotonicTime deadline;
        uavcan::CanIOFlags flags = 0;
        std::uint64_t order = 0;

        TxItem(const uavcan::CanFrame& arg_frame, uavcan::MonotonicTime arg_deadline,
               uavcan::CanIOFlags arg_flags, std::uint64_t arg_order)
            : frame(arg_frame)
            , deadline(arg_deadline)
            , flags(arg_flags)
            , order(arg_order)
        { }

        bool operator<(const TxItem& rhs) const
        {
            if (frame.priorityLowerThan(rhs.frame)) {
                return true;
            }
            if (frame.priorityHigherThan(rhs.frame)) {
                return false;
            }
            return order > rhs.order;
        }
    };

    struct RxItem
    {
        uavcan::CanFrame frame;
        uavcan::MonotonicTime ts_mono;
        uavcan::UtcTime ts_utc;
        uavcan::CanIOFlags flags;

        RxItem()
            : flags(0)
        { }
    };

    void _pollWrite();

    void _pollRead();

    int _write(const uavcan::CanFrame& frame) const;

    int _read(uavcan::CanFrame& frame, uavcan::UtcTime& ts_utc, bool& loopback) const;

    void _incrementNumFramesInSocketTxQueue();

    void _confirmSentFrame();

    bool _wasInPendingLoopbackSet(const uavcan::CanFrame& frame);

    bool _checkHWFilters(const can_frame& frame) const;

    void _registerError(SocketCanError e) { _errors[e]++; }

    uint32_t _bitrate;

    bool _initialized;

    int _fd;

    const unsigned _max_frames_in_socket_tx_queue;
    unsigned _frames_in_socket_tx_queue;
    uint64_t _tx_frame_counter;

    std::map<SocketCanError, uint64_t> _errors;
    std::priority_queue<TxItem> _tx_queue;
    std::queue<RxItem> _rx_queue;
    std::unordered_multiset<uint32_t> _pending_loopback_ids;
    std::vector<can_filter> _hw_filters_container;
};

class CANManager: public AP_HAL::CANManager {
public:
    static CANManager *from(AP_HAL::CANManager *can)
    {
        return static_cast<CANManager*>(can);
    }

    CANManager() { _ifaces.reserve(uavcan::MaxCanIfaces); }
    ~CANManager() { }

    void _timer_tick();

    //These methods belong to AP_HAL::CANManager
    
    virtual bool begin(uint32_t bitrate, uint8_t can_number) override;

    virtual void initialized(bool val);
    virtual bool is_initialized();

    AP_UAVCAN *p_uavcan;

    virtual AP_UAVCAN *get_UAVCAN(void) override;
    virtual void set_UAVCAN(AP_UAVCAN *uavcan) override;

    //These methods belong to ICanDriver (which is an ancestor of AP_HAL::CANManager)
    
    virtual CAN* getIface(uint8_t iface_index) override;

    virtual uint8_t getNumIfaces() const override { return _ifaces.size(); }

    virtual int16_t select(uavcan::CanSelectMasks& inout_masks,
                   const uavcan::CanFrame* (&pending_tx)[uavcan::MaxCanIfaces], uavcan::MonotonicTime blocking_deadline) override;

    int init(uint8_t can_number);

    int addIface(const std::string& iface_name);

private:
    class IfaceWrapper : public CAN
    {
        bool _down = false;

    public:
        IfaceWrapper(int fd) : CAN(fd) { }

        void updateDownStatusFromPollResult(const pollfd& pfd);

        bool isDown() const { return _down; }
    };

    bool _initialized;

    std::vector<std::unique_ptr<IfaceWrapper>> _ifaces;
};

}