src/posix/platform/spi_interface.hpp

/*
 *  Copyright (c) 2019, The OpenThread Authors.
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 *     derived from this software without specific prior written permission.
 *
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/**
 * @file
 *   This file includes definitions for the SPI interface to radio (RCP).
 */

#ifndef POSIX_APP_SPI_INTERFACE_HPP_
#define POSIX_APP_SPI_INTERFACE_HPP_

#include "openthread-posix-config.h"

#include "platform-posix.h"
#include "lib/hdlc/hdlc.hpp"
#include "lib/spinel/spinel_interface.hpp"

#include <openthread/openthread-system.h>

#if OPENTHREAD_POSIX_CONFIG_RCP_BUS == OT_POSIX_RCP_BUS_SPI

#include "ncp/ncp_spi.hpp"

namespace ot {
namespace Posix {

/**
 * This class defines an SPI interface to the Radio Co-processor (RCP).
 *
 */
class SpiInterface
{
public:
    /**
     * This constructor initializes the object.
     *
     * @param[in] aCallback         A reference to a `Callback` object.
     * @param[in] aCallbackContext  The context pointer passed to the callback.
     * @param[in] aFrameBuffer      A reference to a `RxFrameBuffer` object.
     *
     */
    SpiInterface(Spinel::SpinelInterface::ReceiveFrameCallback aCallback,
                 void *                                        aCallbackContext,
                 Spinel::SpinelInterface::RxFrameBuffer &      aFrameBuffer);

    /**
     * This destructor deinitializes the object.
     *
     */
    ~SpiInterface(void);

    /**
     * This method initializes the interface to the Radio Co-processor (RCP).
     *
     * @note This method should be called before reading and sending spinel frames to the interface.
     *
     * @param[in]  aRadioUrl          Arguments parsed from radio url.
     *
     * @retval OT_ERROR_NONE          The interface is initialized successfully.
     * @retval OT_ERROR_ALREADY       The interface is already initialized.
     * @retval OT_ERROR_INVALID_ARGS  The UART device or executable cannot be found or failed to open/run.
     *
     */
    otError Init(const Url::Url &aRadioUrl);

    /**
     * This method deinitializes the interface to the RCP.
     *
     */
    void Deinit(void);

    /**
     * This method encodes and sends a spinel frame to Radio Co-processor (RCP) over the socket.
     *
     * @param[in] aFrame     A pointer to buffer containing the spinel frame to send.
     * @param[in] aLength    The length (number of bytes) in the frame.
     *
     * @retval OT_ERROR_NONE     Successfully encoded and sent the spinel frame.
     * @retval OT_ERROR_BUSY     Failed due to another operation is on going.
     * @retval OT_ERROR_NO_BUFS  Insufficient buffer space available to encode the frame.
     * @retval OT_ERROR_FAILED   Failed to call the SPI driver to send the frame.
     *
     */
    otError SendFrame(const uint8_t *aFrame, uint16_t aLength);

    /**
     * This method waits for receiving part or all of spinel frame within specified interval.
     *
     * @param[in]  aTimeout  The timeout value in microseconds.
     *
     * @retval OT_ERROR_NONE             Part or all of spinel frame is received.
     * @retval OT_ERROR_RESPONSE_TIMEOUT No spinel frame is received within @p aTimeout.
     *
     */
    otError WaitForFrame(uint64_t aTimeoutUs);

    /**
     * This method updates the file descriptor sets with file descriptors used by the radio driver.
     *
     * @param[inout]  aReadFdSet   A reference to the read file descriptors.
     * @param[inout]  aWriteFdSet  A reference to the write file descriptors.
     * @param[inout]  aMaxFd       A reference to the max file descriptor.
     * @param[inout]  aTimeout     A reference to the timeout.
     *
     */
    void UpdateFdSet(fd_set &aReadFdSet, fd_set &aWriteFdSet, int &aMaxFd, struct timeval &aTimeout);

    /**
     * This method performs radio driver processing.
     *
     * @param[in]   aContext        The context containing fd_sets.
     *
     */
    void Process(const RadioProcessContext &aContext);

    /**
     * This method returns the bus speed between the host and the radio.
     *
     * @returns   Bus speed in bits/second.
     *
     */
    uint32_t GetBusSpeed(void) const { return ((mSpiDevFd >= 0) ? mSpiSpeedHz : 0); }

    /**
     * This method is called when RCP failure detected and resets internal states of the interface.
     *
     */
    void OnRcpReset(void);

    /**
     * This method is called when RCP is reset to recreate the connection with it.
     * Intentionally empty.
     *
     */
    otError ResetConnection(void) { return OT_ERROR_NONE; }

private:
    int     SetupGpioHandle(int aFd, uint8_t aLine, uint32_t aHandleFlags, const char *aLabel);
    int     SetupGpioEvent(int aFd, uint8_t aLine, uint32_t aHandleFlags, uint32_t aEventFlags, const char *aLabel);
    void    SetGpioValue(int aFd, uint8_t aValue);
    uint8_t GetGpioValue(int aFd);

    void InitResetPin(const char *aCharDev, uint8_t aLine);
    void InitIntPin(const char *aCharDev, uint8_t aLine);
    void InitSpiDev(const char *aPath, uint8_t aMode, uint32_t aSpeed);
    void TriggerReset(void);

    uint8_t *GetRealRxFrameStart(uint8_t *aSpiRxFrameBuffer, uint8_t aAlignAllowance, uint16_t &aSkipLength);
    otError  DoSpiTransfer(uint8_t *aSpiRxFrameBuffer, uint32_t aTransferLength);
    otError  PushPullSpi(void);

    bool CheckInterrupt(void);
    void LogStats(void);
    void LogError(const char *aString);
    void LogBuffer(const char *aDesc, const uint8_t *aBuffer, uint16_t aLength, bool aForce);

    enum
    {
        kSpiModeMax           = 3,
        kSpiAlignAllowanceMax = 16,
        kSpiFrameHeaderSize   = 5,
        kSpiBitsPerWord       = 8,
        kSpiTxRefuseWarnCount = 30,
        kSpiTxRefuseExitCount = 100,
        kImmediateRetryCount  = 5,
        kFastRetryCount       = 15,
        kDebugBytesPerLine    = 16,
        kGpioIntAssertState   = 0,
        kGpioResetAssertState = 0,
    };

    enum
    {
        kMsecPerSec              = 1000,
        kUsecPerMsec             = 1000,
        kSpiPollPeriodUs         = kMsecPerSec * kUsecPerMsec / 30,
        kSecPerDay               = 60 * 60 * 24,
        kResetHoldOnUsec         = 10 * kUsecPerMsec,
        kImmediateRetryTimeoutUs = 1 * kUsecPerMsec,
        kFastRetryTimeoutUs      = 10 * kUsecPerMsec,
        kSlowRetryTimeoutUs      = 33 * kUsecPerMsec,
    };

    enum
    {
        kMaxFrameSize = Spinel::SpinelInterface::kMaxFrameSize,
    };

    Spinel::SpinelInterface::ReceiveFrameCallback mReceiveFrameCallback;
    void *                                        mReceiveFrameContext;
    Spinel::SpinelInterface::RxFrameBuffer &      mRxFrameBuffer;

    int mSpiDevFd;
    int mResetGpioValueFd;
    int mIntGpioValueFd;

    uint8_t  mSpiMode;
    uint8_t  mSpiAlignAllowance;
    uint32_t mSpiResetDelay;
    uint16_t mSpiCsDelayUs;
    uint16_t mSpiSmallPacketSize;
    uint32_t mSpiSpeedHz;

    uint64_t mSlaveResetCount;
    uint64_t mSpiFrameCount;
    uint64_t mSpiValidFrameCount;
    uint64_t mSpiGarbageFrameCount;
    uint64_t mSpiDuplexFrameCount;
    uint64_t mSpiUnresponsiveFrameCount;
    uint64_t mSpiRxFrameCount;
    uint64_t mSpiRxFrameByteCount;
    uint64_t mSpiTxFrameCount;
    uint64_t mSpiTxFrameByteCount;

    bool     mSpiTxIsReady;
    uint16_t mSpiTxRefusedCount;
    uint16_t mSpiTxPayloadSize;
    uint8_t  mSpiTxFrameBuffer[kMaxFrameSize + kSpiAlignAllowanceMax];

    bool     mDidPrintRateLimitLog;
    uint16_t mSpiSlaveDataLen;

    // Non-copyable, intentionally not implemented.
    SpiInterface(const SpiInterface &);
    SpiInterface &operator=(const SpiInterface &);
};

} // namespace Posix
} // namespace ot

#endif // OPENTHREAD_POSIX_CONFIG_RCP_BUS == OT_POSIX_RCP_BUS_SPI
#endif // POSIX_APP_SPI_INTERFACE_HPP_