CAN.h

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/*
 * Copyright (C) 2014 Pavel Kirienko <pavel.kirienko@gmail.com>
 *
 * With modifications for Ardupilot CAN driver
 * Copyright (C) 2017 Eugene Shamaev
 */

#pragma once

#include "AP_HAL_VRBRAIN.h"
#include <systemlib/perf_counter.h>
#include <AP_HAL/CAN.h>
#include <pthread.h>
#include <semaphore.h>

#include "bxcan.h"
#include "AP_HAL/utility/RingBuffer.h"
                                      
#if defined(GPIO_CAN2_RX) && defined(GPIO_CAN2_TX)
#define CAN_STM32_NUM_IFACES 2
#else
#define CAN_STM32_NUM_IFACES 1
#endif

#define CAN_STM32_RX_QUEUE_SIZE 64

namespace VRBRAIN {
static const int16_t ErrUnknown = 1000; 
static const int16_t ErrNotImplemented = 1001; 
static const int16_t ErrInvalidBitRate = 1002; 
static const int16_t ErrLogic = 1003; 
static const int16_t ErrUnsupportedFrame = 1004; 
static const int16_t ErrMsrInakNotSet = 1005; 
static const int16_t ErrMsrInakNotCleared = 1006; 
static const int16_t ErrBitRateNotDetected = 1007; 
static const int16_t ErrFilterNumConfigs = 1008; 

struct CanRxItem {
    uint64_t utc_usec;
    uavcan::CanFrame frame;
    uavcan::CanIOFlags flags;
    CanRxItem() :
        utc_usec(0), flags(0)
    {
    }
};

struct CriticalSectionLocker {
    const irqstate_t flags_;

    CriticalSectionLocker() :
        flags_(irqsave())
    {
    }

    ~CriticalSectionLocker()
    {
        irqrestore(flags_);
    }
};

namespace clock {
uint64_t getUtcUSecFromCanInterrupt();
uavcan::MonotonicTime getMonotonic();
}

class BusEvent: uavcan::Noncopyable {
public:
    BusEvent(VRBRAINCANManager& can_driver);
    ~BusEvent();

    bool wait(uavcan::MonotonicDuration duration);
    static void signalFromCallOut(BusEvent *sem);

    void signalFromInterrupt();
    sem_t _wait_semaphore;
    volatile uint16_t _signal;
};

class VRBRAINCAN: public AP_HAL::CAN {
    struct Timings {
        uint16_t prescaler;
        uint8_t sjw;
        uint8_t bs1;
        uint8_t bs2;

        Timings() :
            prescaler(0), sjw(0), bs1(0), bs2(0)
        {
        }
    };

    struct TxItem {
        uavcan::MonotonicTime deadline;
        uavcan::CanFrame frame;

        bool pending;

        bool loopback;

        bool abort_on_error;

        TxItem() :
            pending(false), loopback(false), abort_on_error(false)
        {
        }
    };

    enum {
        NumTxMailboxes = 3
    };
    enum {
        NumFilters = 14
    };

    static const uint32_t TSR_ABRQx[NumTxMailboxes];

    ObjectBuffer<CanRxItem> rx_queue_;
    bxcan::CanType* const can_;
    uint64_t error_cnt_;
    uint32_t served_aborts_cnt_;
    BusEvent* update_event_;
    TxItem pending_tx_[NumTxMailboxes];
    uint8_t peak_tx_mailbox_index_;
    const uint8_t self_index_;

    bool had_activity_;

    uint32_t bitrate_;

    int computeTimings(uint32_t target_bitrate, Timings& out_timings);

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

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

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

    virtual uint16_t getNumFilters() const override
    {
        return NumFilters;
    }

    void handleTxMailboxInterrupt(uint8_t mailbox_index, bool txok, uint64_t utc_usec);

    bool waitMsrINakBitStateChange(bool target_state);

    bool initialized_;
public:
    enum {
        MaxRxQueueCapacity = 254
    };

    enum OperatingMode {
        NormalMode, SilentMode
    };

    VRBRAINCAN(bxcan::CanType* can, BusEvent* update_event, uint8_t self_index, uint8_t rx_queue_capacity) :
        rx_queue_(rx_queue_capacity), can_(can), error_cnt_(0), served_aborts_cnt_(0), update_event_(
            update_event), peak_tx_mailbox_index_(0), self_index_(self_index), had_activity_(false), bitrate_(
                0), initialized_(false)
    {
        UAVCAN_ASSERT(self_index_ < CAN_STM32_NUM_IFACES);
    }

    int init(const uint32_t bitrate, const OperatingMode mode);

    void set_update_event(BusEvent* update_event)
    {
        update_event_ = update_event;
    }

    void handleTxInterrupt(uint64_t utc_usec);
    void handleRxInterrupt(uint8_t fifo_index, uint64_t utc_usec);

    void pollErrorFlagsFromISR();

    void discardTimedOutTxMailboxes(uavcan::MonotonicTime current_time);

    bool canAcceptNewTxFrame(const uavcan::CanFrame& frame) const;
    bool isRxBufferEmpty() const;

    virtual uint64_t getErrorCount() const override;

    uint32_t getVoluntaryTxAbortCount() const
    {
        return served_aborts_cnt_;
    }

    unsigned getRxQueueLength() const;

    bool hadActivity();

    uint8_t getPeakNumTxMailboxesUsed() const
    {
        return uint8_t(peak_tx_mailbox_index_ + 1);
    }

    bool begin(uint32_t bitrate) override;
    void end() override
    {
    }

    void reset() override;

    int32_t tx_pending() override;
    int32_t available() override;

    bool is_initialized() override;
};

class VRBRAINCANManager: public AP_HAL::CANManager {
    BusEvent update_event_;
    VRBRAINCAN if0_;
    VRBRAINCAN if1_;

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

    void initOnce(uint8_t can_number);

    bool initialized_;

    VRBRAINCAN* ifaces[CAN_STM32_NUM_IFACES];
    uint8_t _ifaces_num;
    uint8_t _ifaces_out_to_in[CAN_STM32_NUM_IFACES];

    AP_UAVCAN *p_uavcan;

public:
    VRBRAINCANManager();

    uavcan::CanSelectMasks makeSelectMasks(const uavcan::CanFrame* (&pending_tx)[uavcan::MaxCanIfaces]) const;

    bool hasReadableInterfaces() const;

    int init(const uint32_t bitrate, const VRBRAINCAN::OperatingMode mode, uint8_t can_number);

    virtual VRBRAINCAN* getIface(uint8_t iface_index) override;
    VRBRAINCAN* getIface_out_to_in(uint8_t iface_index);

    virtual uint8_t getNumIfaces() const override
    {
        return _ifaces_num;
    }

    bool hadActivity();

    bool begin(uint32_t bitrate, uint8_t can_number) override;

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

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