/**
 * @file canfd.cpp
 * @brief CANFD 通信模块实现。
 */

#include "main.h"
#include "device/canfd.h"
#include "sys/config.h"
#include "sys/critical.h"
#include "sys/cpu_load.h"
#include "sys/systick.h"
#include "sys/task_manager.h"
#include <cstring>

namespace {

/* 纯软件延时循环(不依赖 SysTick,可在任何中断状态下使用) */
static inline void spinDelay(uint32_t loops) {
    for (volatile uint32_t d = 0; d < loops; ++d) { }
}

struct CanChannelConfig {
    uint32_t canPeriph;
    rcu_periph_enum canRcu;
    uint32_t txPort;
    uint32_t txPin;
    uint32_t rxPort;
    uint32_t rxPin;
    uint32_t slpPort;
    uint32_t slpPin;
    IRQn_Type txIrq;
    IRQn_Type rx0Irq;
    uint8_t filterNumber;
};

constexpr CanChannelConfig kChannels[] = {
    { CAN0, RCU_CAN0, GPIOA, GPIO_PIN_12, GPIOA, GPIO_PIN_11, GPIOA, GPIO_PIN_8,  CAN0_TX_IRQn, CAN0_RX0_IRQn, 0U  },
    { CAN1, RCU_CAN1, GPIOB, GPIO_PIN_13, GPIOB, GPIO_PIN_12, GPIOB, GPIO_PIN_14, CAN1_TX_IRQn, CAN1_RX0_IRQn, 14U },
    { CAN2, RCU_CAN2, GPIOE, GPIO_PIN_1,  GPIOE, GPIO_PIN_0,  GPIOB, GPIO_PIN_9,  CAN2_TX_IRQn, CAN2_RX0_IRQn, 2U  },
};

constexpr size_t kChannelCount = sizeof(kChannels) / sizeof(kChannels[0]);

/* ===== 通道使能开关：在 sys/config.h 中修改 CONFIG_CAN_CHx_ENABLE ===== */
constexpr bool kChannelEnabled[kChannelCount] = {
    CONFIG_CAN_CH0_ENABLE,
    CONFIG_CAN_CH1_ENABLE,
    CONFIG_CAN_CH2_ENABLE,
};

constexpr uint32_t kCanRxParseTaskMask = (1UL << TASK_CAN_RX_PARSE);

static const char *canLastErrorName(uint32_t errReg)
{
    static const char *const names[] = {
        "NONE", "STUFF", "FORM", "ACK", "BIT_RECESSIVE", "BIT_DOMINANT", "CRC", "SOFTWARE"
    };
    return names[(errReg >> 4U) & 0x07U];
}

#if (CONFIG_CAN_STARTUP_BUS_TEST_ENABLE != 0)
struct CanSelfTestResult {
    bool txReq;
    uint8_t mailbox;
    uint8_t txState;
    uint32_t stat;
    uint32_t err;
    uint32_t tec;
    uint32_t rec;
    bool busOff;
};

static CanSelfTestResult runSelfTestFrame(uint8_t channelIndex, uint32_t extId, const uint8_t *data, uint8_t len, bool fd, bool brs)
{
    CanSelfTestResult result{};
    result.mailbox = CAN_NOMAILBOX;
    result.txState = CAN_TRANSMIT_FAILED;

    if (channelIndex >= kChannelCount || data == nullptr || len == 0U || len > 64U) {
        return result;
    }

    can_trasnmit_message_struct tx_msg{};
    can_struct_para_init(CAN_TX_MESSAGE_STRUCT, &tx_msg);
    tx_msg.tx_efid = extId;
    tx_msg.tx_ff = CAN_FF_EXTENDED;
    tx_msg.tx_ft = CAN_FT_DATA;
    tx_msg.tx_dlen = len;
#ifdef GD32E508
    tx_msg.fd_flag = fd ? ENABLE : DISABLE;
    tx_msg.fd_brs = (fd && brs) ? ENABLE : DISABLE;
    tx_msg.fd_esi = CAN_ESI_DOMINANT;
#endif
    for (uint8_t i = 0U; i < len; ++i) {
        tx_msg.tx_data[i] = data[i];
    }

    const uint32_t canPeriph = kChannels[channelIndex].canPeriph;
    result.mailbox = can_message_transmit(canPeriph, &tx_msg);
    result.txReq = (result.mailbox != CAN_NOMAILBOX);

    spinDelay(40000U);

    if (result.txReq) {
        result.txState = static_cast<uint8_t>(can_transmit_states(canPeriph, result.mailbox));
        if (result.txState == CAN_TRANSMIT_PENDING) {
            (void)can_transmission_stop(canPeriph, result.mailbox);
        }
    }

    result.stat = CAN_STAT(canPeriph);
    result.err = CAN_ERR(canPeriph);
    result.tec = (result.err >> 16) & 0xFFU;
    result.rec = (result.err >> 24) & 0xFFU;
    result.busOff = (result.err & CAN_ERR_BOERR) != 0U;
    return result;
}
#endif /* CONFIG_CAN_STARTUP_BUS_TEST_ENABLE */

/**
 * @brief 对 CAN 外设执行完整硬件级复位（SWRST + RCU 电源周期）。
 * @note  解决 GD32E508 CAN1 反复初始化后卡死在 init mode 的问题。
 *        步骤：软件复位 → 长延时 → 关时钟 → 长延时 → 开时钟 → 长延时 → 残留状态清理。
 */
static void hardResetCan(uint32_t canPeriph, rcu_periph_enum canRcu)
{
    /* 1. 触发 SWRST 软件复位 */
    CAN_CTL(canPeriph) |= CAN_CTL_SWRST;
    spinDelay(100000U);

    /* 2. 确认 SWRST 已被硬件自动清零；若未清零则强制写 0 并等待 */
    if (CAN_CTL(canPeriph) & CAN_CTL_SWRST) {
        CAN_CTL(canPeriph) &= ~CAN_CTL_SWRST;
        spinDelay(50000U);
    }

    /* 3. 关 RCU 时钟，等待外设域完全放电 */
    rcu_periph_clock_disable(canRcu);
    spinDelay(200000U);  /* ~1.1ms @180MHz */

    /* 4. 重新开时钟，等待外设域上电稳定 */
    rcu_periph_clock_enable(canRcu);
    spinDelay(200000U);  /* ~1.1ms @180MHz */

    /* 5. can_deinit() 走标准固件库复位流程 */
    can_deinit(canPeriph);

    /* 6. 若复位后 IWMOD 仍然置位（外设残留状态），强制清 init mode */
    if (CAN_CTL(canPeriph) & CAN_CTL_IWMOD) {
        CAN_CTL(canPeriph) &= ~CAN_CTL_IWMOD;
        for (volatile uint32_t d = 0; d < 100000U; ++d) {
            if ((CAN_STAT(canPeriph) & CAN_STAT_IWS) == 0U) break;
        }
    }
}

} // namespace

CanFd::Diag     CanFd::s_diag{};
CanFd::RxQueue  CanFd::s_rxQueues[3]{};
CanFd::TxQueue  CanFd::s_txQueues[3]{};
uint8_t         CanFd::s_nextConsumeChannel = 0U;
volatile CanFd::Mode    CanFd::s_mode = CanFd::Mode::kModeAllPass;
CanFd::ChannelStats     CanFd::s_channelStats[3]{};
CanFd::ChannelFeedback  CanFd::s_feedback[3]{};
uint32_t                CanFd::s_feedbackSeq = 0U;
CanFd::IdSnapshotTable  CanFd::s_idSnapshot[3]{};
bool                    CanFd::s_channelHwOk[3]{};

/* TX 错误事件标志（ARD=1 单发丢帧通知）：TX 完成 ISR 置位，主循环
 * consumeTxError() 读清；单写单读，无锁。 */
static volatile bool s_txErrorEvent[3]{};

/**
 * @brief 查询指定通道是否已使能。
 */
bool CanFd::isChannelEnabled(uint8_t channelIndex)
{
    return (channelIndex < kChannelCount) && kChannelEnabled[channelIndex];
}

/**
 * @brief 初始化三路 CANFD 相关 GPIO。
 * @param[in]  无。
 * @param[out] 无。
 * @retval    无返回值。
 * @note      为 CAN0/CAN1/CAN2 的 TX、RX 及收发器 SLP 控制脚统一完成 GPIO 时钟与模式配置。
 */
void CanFd::initGpio()
{
    rcu_periph_clock_enable(RCU_GPIOA);
    rcu_periph_clock_enable(RCU_GPIOB);
    rcu_periph_clock_enable(RCU_GPIOE);
    rcu_periph_clock_enable(RCU_AF);
#ifdef GPIO_CAN0_PARTIAL_REMAP
    /* Bootloader uses CAN0 on PB8/PB9 and jumps to APP without a system reset,
     * so AFIO_PCF0 survives can_deinit(). Restore APP mapping PA11/P12 here. */
    gpio_pin_remap_config(GPIO_CAN0_PARTIAL_REMAP, DISABLE);
#endif
#ifdef GPIO_CAN0_FULL_REMAP
    gpio_pin_remap_config(GPIO_CAN0_FULL_REMAP, DISABLE);
#endif
#ifdef GPIO_CAN1_REMAP
    /* CAN1_REMAP=0 selects PB12=RX and PB13=TX on GD32E508. */
    gpio_pin_remap_config(GPIO_CAN1_REMAP, DISABLE);
#endif
#ifdef AFIO_PE0_CAN2_CFG
    gpio_afio_port_config(AFIO_PE0_CAN2_CFG, ENABLE);
#endif
#ifdef AFIO_PE1_CAN2_CFG
    gpio_afio_port_config(AFIO_PE1_CAN2_CFG, ENABLE);
#endif

    CAN_LOGI("[CAN-GPIO] AFIO_PCF0=0x%08lX CAN0=PA11/PA12 CAN1=PB12/PB13\r\n",
           static_cast<unsigned long>(AFIO_PCF0));

    for(size_t i = 0; i < kChannelCount; ++i) {
        const auto &ch = kChannels[i];
        gpio_init(ch.rxPort, GPIO_MODE_IPU, GPIO_OSPEED_50MHZ, ch.rxPin);
        gpio_init(ch.txPort, GPIO_MODE_AF_PP, GPIO_OSPEED_50MHZ, ch.txPin);
        gpio_init(ch.slpPort, GPIO_MODE_OUT_PP, GPIO_OSPEED_50MHZ, ch.slpPin);
        /* 上电先 STB=1（待机），延时后再进入 Normal */
        gpio_bit_set(ch.slpPort, ch.slpPin);
    }
}

/**
 * @brief 为指定 CAN 控制器配置接收过滤器。
 * @param[in]  canPeriph    目标 CAN 外设实例。
 * @param[in]  filterNumber 过滤器编号。
 * @param[in]  mode         目标接收过滤模式。
 * @param[out] 无。
 * @retval    无返回值。
 * @note      kModeAllPass 模式下使用 32 位掩码模式且 mask=0/list=0，硬件直接放行所有标准/扩展帧到 FIFO0；
 *            kModeFilterId 模式下按 CONFIG_CAN_RX_FILTER_ID/MASK 做标准帧掩码匹配。
 */
void CanFd::configureRxFilter(uint32_t canPeriph, uint8_t filterNumber, Mode mode)
{
    can_filter_parameter_struct can_filter{};
    can_filter.filter_number = filterNumber;
    can_filter.filter_mode = CAN_FILTERMODE_MASK;
    can_filter.filter_bits = CAN_FILTERBITS_32BIT;
    if (mode == Mode::kModeAllPass || mode == Mode::kModeBridge0To12) {
        /* 全部接收：列表与掩码都为 0，硬件不再对 ID 做比较。 */
        can_filter.filter_list_high = 0x0000U;
        can_filter.filter_list_low = 0x0000U;
        can_filter.filter_mask_high = 0x0000U;
        can_filter.filter_mask_low = 0x0000U;
    } else {
        can_filter.filter_list_high = static_cast<uint16_t>((CONFIG_CAN_RX_FILTER_ID & 0x7FFU) << 5U);
        can_filter.filter_list_low = 0x0000U;
        can_filter.filter_mask_high = static_cast<uint16_t>((CONFIG_CAN_RX_FILTER_MASK & 0x7FFU) << 5U);
        can_filter.filter_mask_low = static_cast<uint16_t>(1U << 2U);
    }
    can_filter.filter_fifo_number = CAN_FIFO0;
    can_filter.filter_enable = ENABLE;
    can_filter_init(canPeriph, &can_filter);
}

/**
 * @brief 配置指定 CAN 控制器的标称仲裁段位时序。
 * @param[in]  canPeriph 目标 CAN 外设实例。
 * @param[out] 无。
 * @retval    无返回值。
 * @note      时钟源为 APB1=90MHz；按 CONFIG_CAN_NOMINAL_* 宏配置，目标 1 Mbps。
 *            实际波特率 = 90MHz / (CONFIG_CAN_NOMINAL_PRESCALER × (1+BS1+BS2))。
 */
bool CanFd::initNominalTiming(uint32_t canPeriph)
{
    can_parameter_struct can_parameter{};

    can_struct_para_init(CAN_INIT_STRUCT, &can_parameter);
    can_parameter.time_triggered = DISABLE;
    can_parameter.auto_bus_off_recovery = ENABLE;
    can_parameter.auto_wake_up = DISABLE;
    can_parameter.auto_retrans = ENABLE;  /* 默认自动重发兜底偶发 ACK 丢失；OTA 停等协议期间由 setChannelAutoRetrans(ch,false) 临时关闭，避免重发打穿电机单缓冲 RX */
    can_parameter.rec_fifo_overwrite = ENABLE;
    can_parameter.trans_fifo_order = ENABLE;
    can_parameter.working_mode = CAN_NORMAL_MODE;
    can_parameter.resync_jump_width = CONFIG_CAN_NOMINAL_SJW;
    can_parameter.time_segment_1 = CONFIG_CAN_NOMINAL_BS1;
    can_parameter.time_segment_2 = CONFIG_CAN_NOMINAL_BS2;
    can_parameter.prescaler = CONFIG_CAN_NOMINAL_PRESCALER;
    return can_init(canPeriph, &can_parameter) == SUCCESS;
}

/**
 * @brief 配置指定 CAN 控制器的 CAN FD 数据段参数。
 * @param[in]  canPeriph 目标 CAN 外设实例。
 * @param[out] 无。
 * @retval    无返回值。
 * @note      时钟源为 APB1=90MHz；按 CONFIG_CAN_DATA_* 宏配置，目标 2.0 Mbps。
 *            实际数据段波特率 = 90MHz / (CONFIG_CAN_DATA_PRESCALER × (1+BS1+BS2))。
 *            BRS 受 CONFIG_CAN_FD_BRS_ENABLE 控制。
 */
bool CanFd::initFdMode(uint32_t canPeriph)
{
#ifdef GD32E508
    can_fdframe_struct can_fd_parameter{};
    can_fd_tdc_struct can_fd_tdc_parameter{};

    can_struct_para_init(CAN_FD_FRAME_STRUCT, &can_fd_parameter);
    can_fd_parameter.fd_frame = ENABLE;
    can_fd_parameter.excp_event_detect = ENABLE;
    can_fd_parameter.delay_compensation = ENABLE;
    can_fd_tdc_parameter.tdc_filter = 0x04U;
    can_fd_tdc_parameter.tdc_mode = CAN_TDCMOD_CALC_AND_OFFSET;
    can_fd_tdc_parameter.tdc_offset = 0x04U;
    can_fd_parameter.p_delay_compensation = &can_fd_tdc_parameter;
    can_fd_parameter.iso_bosch = CAN_FDMOD_ISO;
    can_fd_parameter.esi_mode = CAN_ESIMOD_HARDWARE;
    can_fd_parameter.data_prescaler = CONFIG_CAN_DATA_PRESCALER;
    can_fd_parameter.data_resync_jump_width = CONFIG_CAN_DATA_SJW;
    can_fd_parameter.data_time_segment_1 = CONFIG_CAN_DATA_BS1;
    can_fd_parameter.data_time_segment_2 = CONFIG_CAN_DATA_BS2;
    return can_fd_init(canPeriph, &can_fd_parameter) == SUCCESS;
#else
    can_fd_function_enable(canPeriph);
    return true;
#endif
}

#if (CONFIG_CAN_STARTUP_DIAG_VERBOSE != 0)
/** @brief 打印 SYS/APB1 时钟与目标波特率。 */
void CanFd::printClockInfo()
{
    CAN_LOGI("[CAN-CLOCK] SYS=%luHz APB1=%luHz nominal=1Mbps data=2Mbps\r\n",
           static_cast<unsigned long>(SystemCoreClock),
           static_cast<unsigned long>(rcu_clock_freq_get(CK_APB1)));
}
#endif

/** @brief 单通道硬件初始化（hardResetCan+重试+退出init mode+中断使能+RX队列清零）。 */
void CanFd::initChannelHardware(uint8_t i)
{
    const auto &ch = kChannels[i];
    if (!kChannelEnabled[i]) {
        s_channelHwOk[i] = false;
        return;
    }
    s_channelHwOk[i] = false;
    rcu_periph_clock_enable(ch.canRcu);
    gpio_bit_reset(ch.slpPort, ch.slpPin); /* STB=0 -> Normal */
    const uint8_t rxLevelBefore = (gpio_input_bit_get(ch.rxPort, ch.rxPin) != RESET) ? 1U : 0U;
    const uint8_t stbLevel = (gpio_output_bit_get(ch.slpPort, ch.slpPin) != RESET) ? 1U : 0U;

    /* 强制复位 + 重试机制：使用 hardResetCan 完整电源周期解决 CAN1 卡死问题 */
    bool nominalOk = false;
    bool fdOk = false;
    for (uint8_t retry = 0U; retry < 5U; ++retry) {
        hardResetCan(ch.canPeriph, ch.canRcu);

        nominalOk = initNominalTiming(ch.canPeriph);
        fdOk = initFdMode(ch.canPeriph);
        if (nominalOk && fdOk) {
            break;  /* 初始化成功，无需重试 */
        }

        /* can_init 失败后外设可能卡在 init mode，先强制退出让下次重试从干净状态开始 */
        CAN_CTL(ch.canPeriph) &= ~CAN_CTL_IWMOD;
        for (volatile uint32_t d = 0; d < 50000U; ++d) {
            if ((CAN_STAT(ch.canPeriph) & CAN_STAT_IWS) == 0U) break;
        }

        LOG_ERR("[CAN-WARN] CH%u init failed (nom=%u fd=%u STAT=0x%08lX), retry %u/5\r\n",
               static_cast<unsigned>(i),
               nominalOk ? 1U : 0U, fdOk ? 1U : 0U,
               static_cast<unsigned long>(CAN_STAT(ch.canPeriph)),
               static_cast<unsigned>(retry + 1U));
    }

    /* 滤波器配置延迟到循环结束后统一执行：
     * CAN1 的 hardResetCan 含 SWRST，会清零 CAN0/CAN1 共享滤波器寄存器，
     * 若在循环内配 CAN0 filter 后再做 CAN1 hardReset，CAN0 filter 会被破坏。 */

    /* 退出 init mode，确保进入 NORMAL 工作模式 */
    CAN_CTL(ch.canPeriph) &= ~CAN_CTL_IWMOD;
    uint32_t exitWait = 0U;
    for (; exitWait < 200000U; ++exitWait) {
        if ((CAN_STAT(ch.canPeriph) & CAN_STAT_IWS) == 0U) {
            break;
        }
    }

    /* 兜底：若仍然卡在 init mode，做一次额外的 SWRST + 强制退出 */
    if (CAN_STAT(ch.canPeriph) & CAN_STAT_IWS) {
        CAN_CTL(ch.canPeriph) |= CAN_CTL_SWRST;
        spinDelay(50000U);
        CAN_CTL(ch.canPeriph) &= ~(CAN_CTL_SWRST | CAN_CTL_IWMOD);
        for (volatile uint32_t d = 0; d < 200000U; ++d) {
            if ((CAN_STAT(ch.canPeriph) & CAN_STAT_IWS) == 0U) break;
        }
        LOG_ERR("[CAN-WARN] CH%u needed extra SWRST to exit init mode (STAT=0x%08lX)\r\n",
               static_cast<unsigned>(i),
               static_cast<unsigned long>(CAN_STAT(ch.canPeriph)));
    }

    const uint32_t statAfterExit = CAN_STAT(ch.canPeriph);
    const uint32_t errAfterExit = CAN_ERR(ch.canPeriph);
    const uint8_t rxLevelAfter = (gpio_input_bit_get(ch.rxPort, ch.rxPin) != RESET) ? 1U : 0U;
    const uint32_t tecAfterExit = (errAfterExit >> 16) & 0xFFU;
    const uint32_t recAfterExit = (errAfterExit >> 24) & 0xFFU;
    /* 正常上电静默：只在本端控制器初始化失败（can_init/can_fd_init 失败或卡 init mode）
     * 时打印一行诊断。TEC/REC 属总线侧状态，未接从站时浮空噪声会累积，不作为打印条件。 */
    const bool exitedInitMode = ((statAfterExit & CAN_STAT_IWS) == 0U);
    if (!nominalOk || !fdOk || !exitedInitMode) {
        LOG_ERR("[CAN-DIAG] CH%u init_nom=%u init_fd=%u exit_ok=%u wait=%lu rx_before=%u rx_after=%u stb=%u STAT=0x%08lX ERR=0x%08lX TEC=%lu REC=%lu\r\n",
               static_cast<unsigned>(i),
               nominalOk ? 1U : 0U,
               fdOk ? 1U : 0U,
               exitedInitMode ? 1U : 0U,
               static_cast<unsigned long>(exitWait),
               static_cast<unsigned>(rxLevelBefore),
               static_cast<unsigned>(rxLevelAfter),
               static_cast<unsigned>(stbLevel),
               static_cast<unsigned long>(statAfterExit),
               static_cast<unsigned long>(errAfterExit),
               static_cast<unsigned long>(tecAfterExit),
               static_cast<unsigned long>(recAfterExit));
    }

    CAN_TSTAT(ch.canPeriph) = CAN_TSTAT_MTF0 | CAN_TSTAT_MTF1 | CAN_TSTAT_MTF2;
    can_interrupt_enable(ch.canPeriph, CAN_INT_TME | CAN_INT_RFNE0 | CAN_INT_RFF0 | CAN_INT_RFO0);
    nvic_irq_enable(ch.txIrq, CONFIG_IRQ_PREEMPT_CAN, static_cast<uint8_t>(i));
    nvic_irq_enable(ch.rx0Irq, CONFIG_IRQ_PREEMPT_CAN, static_cast<uint8_t>(i));

    s_rxQueues[i].head = 0U;
    s_rxQueues[i].tail = 0U;
    s_rxQueues[i].count = 0U;
    s_txQueues[i].head = 0U;
    s_txQueues[i].tail = 0U;
    s_txQueues[i].count = 0U;

    const bool exitOk = ((CAN_STAT(ch.canPeriph) & CAN_STAT_IWS) == 0U);
    s_channelHwOk[i] = (nominalOk && fdOk && exitOk);
}

/** @brief 统一配置三路滤波器（HBC1F + per-channel filter）。 */
void CanFd::configureAllFilters()
{
    /* ===== 统一配置滤波器（必须在所有 hardResetCan 完成之后） =====
     * CAN1 hardResetCan 的 SWRST 会清零 CAN0/CAN1 共享滤波器寄存器域。
     * 若在循环内先配 CAN0 filter、后做 CAN1 hardReset，CAN0 的 filter 0 会被
     * 硬件清零（CAN_FW bit0 = 0），导致 CAN0 无法接收任何帧。
     * 修复方案：所有 hardReset 完成后，再统一配 HBC1F + 三路 filter。 */
    can1_filter_start_bank(14U);  /* CAN0: bank 0-13, CAN1: bank 14-27 */
    for (size_t i = 0; i < kChannelCount; ++i) {
        if (!kChannelEnabled[i]) continue;
        configureRxFilter(kChannels[i].canPeriph, kChannels[i].filterNumber, s_mode);
    }
    CAN_LOGI("[CAN] filters configured post-init: HBC1F=%lu FW=0x%08lX\r\n",
           static_cast<unsigned long>((CAN_FCTL(CAN0) >> 8) & 0x3FU),
           static_cast<unsigned long>(CAN_FW(CAN0)));
}

#if (CONFIG_CAN_STARTUP_DIAG_VERBOSE != 0)
/** @brief 打印初始化结果汇总（BT/DBT/滤波器状态）。 */
void CanFd::printInitResult()
{
    /* ===== 初始化结果汇总 ===== */
    CAN_LOGI("=== CAN INIT RESULT ===\r\n");
    for (size_t i = 0; i < kChannelCount; ++i) {
        const auto &ch = kChannels[i];
        uint32_t stat = CAN_STAT(ch.canPeriph);
        uint32_t bt   = CAN_BT(ch.canPeriph);
        uint32_t dbt  = CAN_DBT(ch.canPeriph);
        bool ok = (stat & CAN_STAT_IWS) == 0U;
        CAN_LOGI("CH%u: %s  BT=0x%08lX DBT=0x%08lX\r\n",
               static_cast<unsigned>(i),
               ok ? "OK" : "FAIL(init_mode)",
               static_cast<unsigned long>(bt),
               static_cast<unsigned long>(dbt));
    }
    /* 滤波器一行 */
    {
        uint32_t fw = CAN_FW(CAN0);
        uint32_t fw2 = CAN_FW(CAN2);
        uint32_t hbc = (CAN_FCTL(CAN0) >> 8) & 0x3FU;
        CAN_LOGI("FILTER: HBC1F=%lu CAN01_FW=0x%08lX(b0=%lu b2=%lu b14=%lu) CAN2_FW=0x%08lX(b2=%lu)\r\n",
               static_cast<unsigned long>(hbc),
               static_cast<unsigned long>(fw),
               static_cast<unsigned long>((fw >> 0) & 1U),
               static_cast<unsigned long>((fw >> 2) & 1U),
               static_cast<unsigned long>((fw >> 14) & 1U),
               static_cast<unsigned long>(fw2),
               static_cast<unsigned long>((fw2 >> 2) & 1U));
    }
}

/** @brief 打印初始化后错误计数器快照（TEC/REC/BOFF/EPV/EW）。 */
void CanFd::printErrorState()
{
    /* ===== 初始化后错误计数器快照（不发帧，避免启动时累积 TEC）===== */
    LOG_ERR("=== CAN INIT ERR STATE ===\r\n");
    for (size_t i = 0; i < kChannelCount; ++i) {
        const auto &ch = kChannels[i];
        uint32_t err = CAN_ERR(ch.canPeriph);
        uint32_t tec = (err >> 16) & 0xFFU;
        uint32_t rec = (err >> 24) & 0xFFU;
        LOG_ERR("CH%u: ERR=0x%08lX TEC=%lu REC=%lu boff=%u epv=%u ew=%u\r\n",
               static_cast<unsigned>(i),
               static_cast<unsigned long>(err),
               static_cast<unsigned long>(tec),
               static_cast<unsigned long>(rec),
               (err & CAN_ERR_BOERR) ? 1U : 0U,  /* BOFF  bit2 */
               (err & CAN_ERR_PERR)  ? 1U : 0U,  /* EPV   bit1 */
               (err & CAN_ERR_WERR)  ? 1U : 0U); /* EWARN bit0 */
    }
}
#endif /* CONFIG_CAN_STARTUP_DIAG_VERBOSE */

#if (CONFIG_CAN_STARTUP_BUS_TEST_ENABLE != 0)
/** @brief 物理总线自测。 */
void CanFd::runSelfTest()
{
    /* ===== Self-test (NORMAL mode, 发到物理总线测 ACK) ===== */
    CAN_LOGI("=== CAN SELF-TEST (normal mode) ===\r\n");
    for (size_t i = 0; i < kChannelCount; ++i) {
        if (!kChannelEnabled[i]) {
            CAN_LOGI("CH%u: SKIP(disabled)\r\n", static_cast<unsigned>(i));
            continue;
        }
        const uint8_t ch = static_cast<uint8_t>(i);
        uint8_t data8[8] = {0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57};
        uint8_t data64[64];
        for (uint8_t j = 0; j < 64U; ++j) data64[j] = 0xA0 + (j & 0x0F);

        const CanSelfTestResult c = runSelfTestFrame(ch, 0x1FFFFF00U | i, data8, 8, false, false);
        const CanSelfTestResult fd = runSelfTestFrame(ch, 0x1FFFFF10U | i, data64, 64, true, false);
#if (CONFIG_CAN_FD_BRS_ENABLE != 0)
        const CanSelfTestResult brs = runSelfTestFrame(ch, 0x1FFFFF20U | i, data64, 64, true, true);
        CAN_LOGI("CH%u: classic=%s(fd=0) fd_nobrs=%s(fd=1) fd_brs=%s(brs=1) TEC=%lu\r\n",
               static_cast<unsigned>(i),
               c.tec == 0 ? "ACK" : "NO_ACK",
               fd.tec == 0 ? "ACK" : "NO_ACK",
               brs.tec == 0 ? "ACK" : "NO_ACK",
               static_cast<unsigned long>(brs.tec > fd.tec ? brs.tec : fd.tec));
#else
        CAN_LOGI("CH%u: classic=%s fd_nobrs=%s TEC=%lu\r\n",
               static_cast<unsigned>(i),
               c.tec == 0 ? "ACK" : "NO_ACK",
               fd.tec == 0 ? "ACK" : "NO_ACK",
               static_cast<unsigned long>(fd.tec));
#endif
    }
}

#endif /* CONFIG_CAN_STARTUP_BUS_TEST_ENABLE */

#if (CONFIG_CAN_STARTUP_LOOPBACK_TEST_ENABLE != 0)
/** @brief 内部回环测试。 */
void CanFd::runLoopbackTest()
{
    /* ===== Loopback 回环测试 (内部 TX→RX，不走物理总线) ===== */
    CAN_LOGI("=== CAN LOOPBACK (internal) ===\r\n");
    for (size_t i = 0; i < kChannelCount; ++i) {
        const auto &ch = kChannels[i];

        if (!kChannelEnabled[i]) {
            CAN_LOGI("CH%u: SKIP(disabled)\r\n", static_cast<unsigned>(i));
            continue;
        }

        if (CAN_STAT(ch.canPeriph) & CAN_STAT_IWS) {
            CAN_LOGI("CH%u: SKIP(stuck_init)\r\n", static_cast<unsigned>(i));
            continue;
        }

        /* 进入 loopback 模式：用固件库 API，失败则用寄存器直接操作兜底 */
        ErrStatus r1 = can_working_mode_set(ch.canPeriph, CAN_MODE_INITIALIZE);
        ErrStatus r2 = can_monitor_mode_set(ch.canPeriph, CAN_LOOPBACK_MODE);
        ErrStatus r3 = can_working_mode_set(ch.canPeriph, CAN_MODE_NORMAL);
        bool lbkmOk = (CAN_BT(ch.canPeriph) & (1U << 30)) != 0U;

        /* 如果 API 失败，尝试直接操作寄存器 */
        if (!lbkmOk) {
            CAN_CTL(ch.canPeriph) |= CAN_CTL_IWMOD;  /* 强制进入 init mode */
            for (volatile uint32_t t = 0; t < 100000U; ++t) {
                if (CAN_STAT(ch.canPeriph) & CAN_STAT_IWS) break;
            }
            CAN_BT(ch.canPeriph) |= (1U << 30);  /* 直接设 LCMOD=1 */
            CAN_CTL(ch.canPeriph) &= ~CAN_CTL_IWMOD;  /* 退出 init mode */
            for (volatile uint32_t t = 0; t < 100000U; ++t) {
                if ((CAN_STAT(ch.canPeriph) & CAN_STAT_IWS) == 0U) break;
            }
            lbkmOk = (CAN_BT(ch.canPeriph) & (1U << 30)) != 0U;
        }

        if (!lbkmOk) {
            CAN_LOGI("CH%u: SKIP(lbk_fail API:%d/%d/%d reg:LCMOD=0)\r\n",
                   static_cast<unsigned>(i), r1, r2, r3);
            /* 恢复 normal */
            CAN_CTL(ch.canPeriph) |= CAN_CTL_IWMOD;
            for (volatile uint32_t t = 0; t < 100000U; ++t) { if (CAN_STAT(ch.canPeriph) & CAN_STAT_IWS) break; }
            CAN_BT(ch.canPeriph) &= ~(3U << 30);
            CAN_CTL(ch.canPeriph) &= ~CAN_CTL_IWMOD;
            for (volatile uint32_t t = 0; t < 100000U; ++t) { if ((CAN_STAT(ch.canPeriph) & CAN_STAT_IWS) == 0U) break; }
            continue;
        }

        /* --- 经典 CAN --- */
        const uint32_t rxB1 = s_channelStats[i].rx_count;
        {
            can_trasnmit_message_struct tx{};
            can_struct_para_init(CAN_TX_MESSAGE_STRUCT, &tx);
            tx.tx_sfid = 0x100U + i; tx.tx_ff = CAN_FF_STANDARD; tx.tx_ft = CAN_FT_DATA; tx.tx_dlen = 8;
            for (uint8_t j = 0; j < 8U; ++j) tx.tx_data[j] = 0x55 + j;
            can_message_transmit(ch.canPeriph, &tx);
        }
        for (volatile uint32_t t = 0; t < 500000U; ++t) {
            if (s_channelStats[i].rx_count > rxB1 || can_receive_message_length_get(ch.canPeriph, CAN_FIFO0)) break;
        }
        /* 消费 FIFO 中可能残留的帧 */
        while (can_receive_message_length_get(ch.canPeriph, CAN_FIFO0) > 0U) {
            can_receive_message_struct rx{}; can_struct_para_init(CAN_RX_MESSAGE_STRUCT, &rx);
            can_message_receive(ch.canPeriph, CAN_FIFO0, &rx);
        }
        bool cOk = (s_channelStats[i].rx_count - rxB1) > 0U;

        /* --- FD no BRS --- */
        const uint32_t rxB2 = s_channelStats[i].rx_count;
        {
            can_trasnmit_message_struct tx{};
            can_struct_para_init(CAN_TX_MESSAGE_STRUCT, &tx);
            tx.tx_sfid = 0x200U + i; tx.tx_ff = CAN_FF_STANDARD; tx.tx_ft = CAN_FT_DATA; tx.tx_dlen = 64;
            tx.fd_flag = ENABLE; tx.fd_brs = DISABLE; tx.fd_esi = CAN_ESI_DOMINANT;
            for (uint8_t j = 0; j < 64U; ++j) tx.tx_data[j] = 0xAA + (j & 0x0F);
            can_message_transmit(ch.canPeriph, &tx);
        }
        for (volatile uint32_t t = 0; t < 500000U; ++t) {
            if (s_channelStats[i].rx_count > rxB2 || can_receive_message_length_get(ch.canPeriph, CAN_FIFO0)) break;
        }
        while (can_receive_message_length_get(ch.canPeriph, CAN_FIFO0) > 0U) {
            can_receive_message_struct rx{}; can_struct_para_init(CAN_RX_MESSAGE_STRUCT, &rx);
            can_message_receive(ch.canPeriph, CAN_FIFO0, &rx);
        }
        bool fdOk = (s_channelStats[i].rx_count - rxB2) > 0U;

        /* --- FD BRS --- */
        const uint32_t rxB3 = s_channelStats[i].rx_count;
        {
            can_trasnmit_message_struct tx{};
            can_struct_para_init(CAN_TX_MESSAGE_STRUCT, &tx);
            tx.tx_sfid = 0x300U + i; tx.tx_ff = CAN_FF_STANDARD; tx.tx_ft = CAN_FT_DATA; tx.tx_dlen = 64;
            tx.fd_flag = ENABLE; tx.fd_brs = ENABLE; tx.fd_esi = CAN_ESI_DOMINANT;
            for (uint8_t j = 0; j < 64U; ++j) tx.tx_data[j] = 0xBB + (j & 0x0F);
            can_message_transmit(ch.canPeriph, &tx);
        }
        for (volatile uint32_t t = 0; t < 500000U; ++t) {
            if (s_channelStats[i].rx_count > rxB3 || can_receive_message_length_get(ch.canPeriph, CAN_FIFO0)) break;
        }
        while (can_receive_message_length_get(ch.canPeriph, CAN_FIFO0) > 0U) {
            can_receive_message_struct rx{}; can_struct_para_init(CAN_RX_MESSAGE_STRUCT, &rx);
            can_message_receive(ch.canPeriph, CAN_FIFO0, &rx);
        }
        bool brsOk = (s_channelStats[i].rx_count - rxB3) > 0U;

        uint32_t tecLb = (CAN_ERR(ch.canPeriph) >> 16) & 0xFFU;
        CAN_LOGI("CH%u: classic=%s fd=%s fd_brs=%s TEC=%lu\r\n",
               static_cast<unsigned>(i),
               cOk ? "PASS" : "FAIL",
               fdOk ? "PASS" : "FAIL",
               brsOk ? "PASS" : "FAIL",
               static_cast<unsigned long>(tecLb));

        /* 回环前后寄存器快照，用于诊断 LCMOD 清除是否干净 */
        uint32_t btBeforeExit = CAN_BT(ch.canPeriph);
        uint32_t ctlBeforeExit = CAN_CTL(ch.canPeriph);

        /* 回到 NORMAL 模式：进 init → 清 LCMOD+SCMOD → 退出 init */
        CAN_CTL(ch.canPeriph) |= CAN_CTL_IWMOD;
        for (volatile uint32_t t = 0; t < 100000U; ++t) { if (CAN_STAT(ch.canPeriph) & CAN_STAT_IWS) break; }
        CAN_BT(ch.canPeriph) &= ~(3U << 30);  /* 清 LCMOD+SCMOD */
        CAN_CTL(ch.canPeriph) &= ~CAN_CTL_IWMOD;
        for (volatile uint32_t t = 0; t < 200000U; ++t) {
            if ((CAN_STAT(ch.canPeriph) & CAN_STAT_IWS) == 0U) break;
        }

        uint32_t errAfterLb = CAN_ERR(ch.canPeriph);
        uint32_t tecAfterLb = (errAfterLb >> 16) & 0xFFU;
        uint32_t recAfterLb = (errAfterLb >> 24) & 0xFFU;
        uint32_t statAfterLb = CAN_STAT(ch.canPeriph);
        CAN_LOGI("CH%u: post-lb TEC=%lu REC=%lu STAT=0x%08lX BT=0x%08lX CTL=0x%08lX\r\n",
               static_cast<unsigned>(i),
               static_cast<unsigned long>(tecAfterLb),
               static_cast<unsigned long>(recAfterLb),
               static_cast<unsigned long>(statAfterLb),
               static_cast<unsigned long>(CAN_BT(ch.canPeriph)),
               static_cast<unsigned long>(CAN_CTL(ch.canPeriph)));
    }
    CAN_LOGI("========================\r\n");
}
#endif /* CONFIG_CAN_STARTUP_LOOPBACK_TEST_ENABLE */

#if (CONFIG_CAN_STARTUP_DIAG_VERBOSE != 0)
/** @brief 全寄存器快照转储（CTL/STAT/BT/DBT/ERR/INTEN/FCTL/FW/RFL0）。 */
void CanFd::dumpRegisters()
{
    /* ===== 初始化后全寄存器快照：诊断 CAN0/CAN1 不收帧 ===== */
    CAN_LOGI("=== POST-INIT FULL REG DUMP ===\r\n");
    for (size_t i = 0; i < kChannelCount; ++i) {
        const auto &ch = kChannels[i];
        uint32_t ctl = CAN_CTL(ch.canPeriph);
        uint32_t stat = CAN_STAT(ch.canPeriph);
        uint32_t bt = CAN_BT(ch.canPeriph);
        uint32_t dbt = CAN_DBT(ch.canPeriph);
        uint32_t err = CAN_ERR(ch.canPeriph);
        uint32_t inten = CAN_INTEN(ch.canPeriph);
        uint32_t fw = (ch.canPeriph == CAN2) ? CAN_FW(CAN2) : CAN_FW(CAN0);
        uint32_t fctl = CAN_FCTL(ch.canPeriph);
        uint32_t rfl0 = CAN_RFIFO0(ch.canPeriph) & 0x3U;  /* RFL0 bits 1:0 */

        bool normalMode = ((stat & CAN_STAT_IWS) == 0U) && ((bt & (3U << 30)) == 0U);
        CAN_LOGI("CH%u: %s CTL=0x%08lX STAT=0x%08lX BT=0x%08lX DBT=0x%08lX\r\n"
               "     ERR=0x%08lX INTEN=0x%08lX FCTL=0x%08lX FW=0x%08lX RFL0=%lu\r\n",
               static_cast<unsigned>(i),
               normalMode ? "NORMAL" : "!!!NOT_NORMAL!!!",
               static_cast<unsigned long>(ctl),
               static_cast<unsigned long>(stat),
               static_cast<unsigned long>(bt),
               static_cast<unsigned long>(dbt),
               static_cast<unsigned long>(err),
               static_cast<unsigned long>(inten),
               static_cast<unsigned long>(fctl),
               static_cast<unsigned long>(fw),
               static_cast<unsigned long>(rfl0));

        /* 逐位解析关键标志 */
        CAN_LOGI("     IWMOD=%u SLPWMOD=%u ARD=%u ABOR=%u | IWS=%u SLPWS=%u | LCMOD=%u SCMOD=%u\r\n",
               (ctl & CAN_CTL_IWMOD) ? 1U : 0U,
               (ctl & CAN_CTL_SLPWMOD) ? 1U : 0U,   /* bit1: sleep mode request */
               (ctl & CAN_CTL_ARD) ? 1U : 0U,        /* bit4: auto retrans disable */
               (ctl & CAN_CTL_ABOR) ? 1U : 0U,       /* bit6: auto bus-off recovery */
               (stat & CAN_STAT_IWS) ? 1U : 0U,
               (stat & CAN_STAT_SLPWS) ? 1U : 0U,
               (bt & (1U << 30)) ? 1U : 0U,   /* LCMOD */
               (bt & (1U << 31)) ? 1U : 0U);  /* SCMOD */
    }
    CAN_LOGI("===============================\r\n");
}
#endif /* CONFIG_CAN_STARTUP_DIAG_VERBOSE */

/**
 * @brief 初始化三路 CANFD 控制器、过滤器、中断与软件队列。
 * @param[in]  无。
 * @param[out] 无。
 * @retval    无返回值。
 * @note      初始化收发器 GPIO 后延时进入 Normal，并启用 FIFO0 中断统计。
 */
void CanFd::init()
{
    s_diag = {};
    s_nextConsumeChannel = 0U;
    s_mode = Mode::kModeAllPass;
    for (size_t i = 0; i < kChannelCount; ++i) {
        s_channelStats[i] = {};
        s_feedback[i] = {};
        s_channelHwOk[i] = false;
    }
    s_feedbackSeq = 0U;

    initGpio();
#if (CONFIG_CAN_STARTUP_DIAG_VERBOSE != 0)
    printClockInfo();
#endif

    /* 收发器待机保持后，延时再进入 Normal */
    constexpr uint32_t kCanPowerOnDeferMs = 200U;
    SysTickTimer::delayMs(kCanPowerOnDeferMs);

    for (uint8_t i = 0; i < kChannelCount; ++i) {
        initChannelHardware(i);
    }
    s_nextConsumeChannel = 0U;

    configureAllFilters();
#if (CONFIG_CAN_STARTUP_DIAG_VERBOSE != 0)
    printInitResult();
    printErrorState();
    dumpRegisters();
#endif
#if (CONFIG_CAN_STARTUP_BUS_TEST_ENABLE != 0)
    runSelfTest();
#endif
#if (CONFIG_CAN_STARTUP_LOOPBACK_TEST_ENABLE != 0)
    runLoopbackTest();
#endif
}

/**
 * @brief L0 轻量自检：无总线发帧，仅校验使能通道控制器自身状态（GD32 侧故障）。
 * @note 1.5.35：不再检查 BUS_OFF/TEC/REC——未接从站的通道 RX 浮空噪声会累积 REC，
 *       「没接设备」不等于错误；总线侧健康由 0xC1 反馈帧运行期上报。
 */
bool CanFd::selfTestL0(uint8_t *fault_code, uint8_t *fault_channel)
{
    bool anyEnabled = false;
    bool allOk = true;
    uint8_t firstCode = kSelfTestOk;
    uint8_t firstCh = 0U;

    for (uint8_t i = 0U; i < static_cast<uint8_t>(kChannelCount); ++i) {
        if (!kChannelEnabled[i]) {
            continue;
        }
        anyEnabled = true;
        const auto &ch = kChannels[i];
        uint8_t code = kSelfTestOk;

        if (!s_channelHwOk[i]) {
            code = kSelfTestHwInit;
        } else if ((CAN_STAT(ch.canPeriph) & CAN_STAT_IWS) != 0U) {
            /* 仍停在初始化模式 */
            code = kSelfTestStuckInit;
        } else if (gpio_output_bit_get(ch.slpPort, ch.slpPin) != RESET) {
            /* STB=0 为 Normal；输出寄存器回读确认配置生效 */
            code = kSelfTestStbLevel;
        }

        if (code != kSelfTestOk) {
            allOk = false;
            if (firstCode == kSelfTestOk) {
                firstCode = code;
                firstCh = i;
            }
            LOG_ERR("[CAN] L0 selftest CH%u FAIL code=%u (STAT=0x%08lX ERR=0x%08lX)\r\n",
                    static_cast<unsigned>(i), static_cast<unsigned>(code),
                    static_cast<unsigned long>(CAN_STAT(ch.canPeriph)),
                    static_cast<unsigned long>(CAN_ERR(ch.canPeriph)));
        }
    }

    if (fault_code != nullptr) {
        *fault_code = firstCode;
    }
    if (fault_channel != nullptr) {
        *fault_channel = firstCh;
    }
    return anyEnabled && allOk;
}

/**
 * @brief 切换 CANFD 接收过滤模式。
 * @param[in]  mode 目标过滤模式。
 * @note      切换时逐路重新配置过滤器；can_filter_init 内部会清 FCTL_FLD，无需手动进入 INITIAL 模式。
 */
void CanFd::setMode(Mode mode)
{
    uint32_t save = RT_CRITICAL_SAVE();
    s_mode = mode;
    for (size_t i = 0; i < kChannelCount; ++i) {
        configureRxFilter(kChannels[i].canPeriph, kChannels[i].filterNumber, mode);
    }
    RT_CRITICAL_RESTORE(save);
}

/**
 * @brief 查询当前 CANFD 接收过滤模式。
 */
CanFd::Mode CanFd::mode()
{
    return s_mode;
}

/**
 * @brief 查询三路 CAN 通道是否存在待消费接收报文。
 * @param[in]  无。
 * @param[out] 无。
 * @retval bool true 表示至少一条接收队列非空，false 表示当前三路均无待消费报文。
 */
bool CanFd::hasRxFrame()
{
    bool found = false;
    uint32_t save = RT_CRITICAL_SAVE();
    for(size_t i = 0; i < kChannelCount; ++i) {
        if(s_rxQueues[i].count != 0U) {
            found = true;
            break;
        }
    }
    RT_CRITICAL_RESTORE(save);
    return found;
}

/**
 * @brief 轮转读取并消费一帧接收报文。
 * @param[in]  无。
 * @param[out] id      输出报文标识符；允许为空。
 * @param[out] data    输出报文数据缓存；允许为空。
 * @param[out] length  输出报文长度；允许为空。
 * @param[out] channel 输出报文来源通道号；允许为空。
 * @retval bool true 表示成功消费一帧报文，false 表示当前三路接收队列均为空。
 * @note      消费顺序采用从 `s_nextConsumeChannel` 开始的轮转扫描，避免长期偏向固定通道。
 */
bool CanFd::consumeRxFrame(uint32_t *id, uint8_t *data, uint8_t *length, uint8_t *channel)
{
    RxFrame localFrame{};
    bool found = false;

    uint32_t save = RT_CRITICAL_SAVE();
    for(size_t n = 0; n < kChannelCount; ++n) {
        const uint8_t idx = static_cast<uint8_t>((s_nextConsumeChannel + n) % kChannelCount);
        auto &queue = s_rxQueues[idx];
        if(queue.count == 0U) {
            continue;
        }

        localFrame = queue.frames[queue.head];
        queue.head = static_cast<uint8_t>((queue.head + 1U) % kRxQueueDepth);
        queue.count--;
        s_nextConsumeChannel = static_cast<uint8_t>((idx + 1U) % kChannelCount);
        found = true;
        break;
    }
    RT_CRITICAL_RESTORE(save);

    if(!found) {
        return false;
    }

    if(channel) *channel = localFrame.channel;
    if(id)      *id = localFrame.id;
    if(length)  *length = localFrame.length;
    if(data) {
        for(uint8_t i = 0; i < localFrame.length; ++i) {
            data[i] = localFrame.data[i];
        }
    }
    return true;
}

/**
 * @brief 直接向指定 CAN 通道发送一帧任意数据报文（扩展帧）。
 * @param[in]  channelIndex 目标 CAN 通道号（0/1/2）。
 * @param[in]  ext_id      扩展帧 ID（29 位）。
 * @param[in]  data        数据负载指针。
 * @param[in]  dlc         数据长度（0~64；0 表示无数据负载/远程类空帧）。
 * @param[in]  periodic    是否为周期性发送；true 时仅允许一个邮箱保持自动重发，
 *                         不主动 abort 旧帧，且跳过 TEC 保护以匹配诊断行为。
 * @retval CanTxResult kOk 表示发送请求已进入硬件邮箱；其它值表示具体失败原因。
 * @note      绕过软件发送队列，直接调用硬件发送；适用于 SPI 桥接等即时发送场景。
 *            网页发送数仅在 TX 中断确认 MTFNERR 后增加，不能用本函数返回值判断总线 ACK。
 */
CanFd::CanTxResult CanFd::transmitFrame(uint8_t channelIndex, uint32_t ext_id,
                                        const uint8_t *data, uint8_t dlc, bool periodic,
                                        bool allow_abort)
{
    /* DLC=0 合法（仅 ID）；DLC>0 时 data 必填 */
    if (channelIndex >= kChannelCount || !kChannelEnabled[channelIndex] || dlc > 64U) {
        return CanTxResult::kErrInvalid;
    }
    if (dlc > 0U && data == nullptr) {
        return CanTxResult::kErrInvalid;
    }

    /* 诊断：捕获任何通过 transmitFrame 发 0x100 DLC=16 的帧（排查幽灵帧来源） */
    if (ext_id == 0x00000100U && dlc == 16U) {
        CAN_LOGI("[CAN-DIAG] TX 0x100 DLC=16 via transmitFrame ch=%u\r\n",
               (unsigned)channelIndex);
    }

    /* BUS_OFF 不再软件拦截——CAN_ERR_BOERR 是粘性标志，控制器恢复后仍置位，
     * 导致总线正常时仍拒绝发送（用户确认其他设备能收到 GD32 帧）。
     * CAN 硬件自带恢复机制（128×11隐性位后自动回 Normal）；
     * 若确实发不出，can_message_transmit 会返回 NOMAILBOX → kErrMailbox。 */
    const uint32_t canPeriph = kChannels[channelIndex].canPeriph;
    /* CAN 硬件自有 error-passive(TEC>127 自动加间隔)
     * 和 bus-off(TEC=256 → 自动恢复) 保护。软件不再做任何发送拦截。 */

    /* 周期发送只允许一个邮箱保持自动重发。无 ACK 时同一帧会持续产生
     * 总线波形；不要每 1ms 再填满其余邮箱，更不能主动 abort 旧帧，否则
     * TX 完成中断会把软件中止累计为发送失败，掩盖真实 TEC/ERRN。 */
    if (periodic) {
        for (uint8_t mb = CAN_MAILBOX0; mb <= CAN_MAILBOX2; ++mb) {
            if (can_transmit_states(canPeriph, mb) == CAN_TRANSMIT_PENDING) {
                return CanTxResult::kErrMailbox;
            }
        }
    }

    can_trasnmit_message_struct tx_msg{};
    can_struct_para_init(CAN_TX_MESSAGE_STRUCT, &tx_msg);
    tx_msg.tx_efid = ext_id;
    tx_msg.tx_ff   = CAN_FF_EXTENDED;
    tx_msg.tx_ft   = CAN_FT_DATA;
    tx_msg.tx_dlen = dlc;
#ifdef GD32E508
    tx_msg.fd_flag = (dlc > 8U) ? ENABLE : DISABLE;
#if (CONFIG_CAN_FD_BRS_ENABLE != 0)
    tx_msg.fd_brs  = (dlc > 8U) ? ENABLE : DISABLE;
#else
    tx_msg.fd_brs  = DISABLE;
#endif
    tx_msg.fd_esi  = CAN_ESI_DOMINANT;
#endif
    if (data != nullptr && dlc > 0U) {
        for (uint8_t i = 0U; i < dlc; ++i) {
            tx_msg.tx_data[i] = data[i];
        }
    }

    uint8_t mailbox = can_message_transmit(canPeriph, &tx_msg);

    /* 非周期业务发送在邮箱全占时保持非阻塞：本函数可能处于 SPI CS 中断链路，不能等待
     * SysTick。若 auto_retrans 因总线无 ACK 卡住全部邮箱，只立即 abort
     * 一个 PENDING 邮箱并重投一次，把中断占用时间控制在寄存器访问级别。
     *
     * ★ allow_abort=false（突发/软件队列路径）时不做 abort：邮箱全满直接返回
     *   kErrMailbox，由 enqueueTx 把帧送入软件队列、TX 完成中断回灌。
     *   否则 abort+重投会把同通道已装载的旧帧顶掉（7 帧同通道突发只发 3 帧）。 */
    if (mailbox == CAN_NOMAILBOX && allow_abort) {
        for (uint8_t mb = CAN_MAILBOX0; mb <= CAN_MAILBOX2; ++mb) {
            if (can_transmit_states(canPeriph, mb) != CAN_TRANSMIT_PENDING) {
                continue;
            }
            if (can_transmission_stop(canPeriph, mb) == SUCCESS) {
                s_diag.tx_abort_count++;
                break;
            }
        }
        mailbox = can_message_transmit(canPeriph, &tx_msg);
    }

    if (mailbox != CAN_NOMAILBOX) {
        s_diag.last_tx_id      = ext_id;
        s_diag.last_tx_channel = channelIndex;
        s_diag.last_payload_length = dlc;
        return CanTxResult::kOk;
    }
    s_diag.error_count++;
    s_channelStats[channelIndex].error_count++;
    static uint32_t s_lastMailboxLogSeq[kChannelCount] = {0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU};
    if (s_lastMailboxLogSeq[channelIndex] != s_feedbackSeq) {
        const uint32_t errAfter = CAN_ERR(canPeriph);
        LOG_ERR("[CAN-TX-REJECT] CH%u MAILBOX ERR=0x%08lX ERRN=%lu(%s) TEC=%lu REC=%lu TSTAT=0x%08lX\r\n",
               static_cast<unsigned>(channelIndex),
               static_cast<unsigned long>(errAfter),
               static_cast<unsigned long>((errAfter >> 4U) & 0x07U),
               canLastErrorName(errAfter),
               static_cast<unsigned long>((errAfter >> 16U) & 0xFFU),
               static_cast<unsigned long>((errAfter >> 24U) & 0xFFU),
               static_cast<unsigned long>(CAN_TSTAT(canPeriph)));
        s_lastMailboxLogSeq[channelIndex] = s_feedbackSeq;
    }
    return CanTxResult::kErrMailbox;
}

/**
 * @brief 突发排入软件 TX 队列（详见头声明）。
 *
 * 场景：电机控制台 0xC7 突发一次发 4 帧同通道命令，
 *       GD32 只有 3 个硬件邮箱，第 4 帧必丢。此队列把超载帧留下来，
 *       TX 完成中断里持续回灌，前端 /can/send_burst 不再因 >3 帧掉帧。
 */
CanFd::CanTxResult CanFd::enqueueTx(uint8_t channelIndex, uint32_t ext_id,
                                    const uint8_t *data, uint8_t dlc)
{
    if (channelIndex >= kChannelCount || !kChannelEnabled[channelIndex] || dlc > 64U) {
        return CanTxResult::kErrInvalid;
    }
    if (dlc > 0U && data == nullptr) {
        return CanTxResult::kErrInvalid;
    }

    TxQueue &q = s_txQueues[channelIndex];

    /* 快速路径：队列空 → 直通硬件邮箱。装得下立即返回，不用等待 TX 完成中断。
     * ★ allow_abort=false：邮箱满时禁止 abort 旧帧顶替（那会把同通道已装载的
     *   旧帧静默丢弃，>3 帧同通道突发只剩最后 3 帧上线），一律落入软件队列，
     *   由 TX 完成中断 drainTxQueueIsr 回灌。 */
    if (q.count == 0U) {
        const CanTxResult r = transmitFrame(channelIndex, ext_id, data, dlc, false, false);
        if (r != CanTxResult::kErrMailbox) {
            return r;   /* 装上了（kOk）或失败原因非邮箱满(kErrInvalid/kErrBusOff) */
        }
        /* 邮箱满：落入下面的入队路径 */
    }

    /* 关中段：EXTI15(SPI burst) 与 CANx TX ISR 并发，保护 head/tail/count。
     * 用 CMSIS NVIC 接口（SPL 的 nvic_irq_enable 是 3 参版）。
     * 关的是该通道自身的 txIrq，避免关全局影响其他通道的实时性。 */
    const IRQn_Type irqn = kChannels[channelIndex].txIrq;
    NVIC_DisableIRQ(irqn);

    if (q.count >= kTxQueueDepth) {
        /* 队列也满了：彻底装不下。此时不能再返回 kOk，
         * 否则前端会误判成功；只能丢弃并返回 kErrMailbox。 */
        NVIC_EnableIRQ(irqn);
        s_diag.error_count++;
        s_channelStats[channelIndex].error_count++;
        return CanTxResult::kErrMailbox;
    }

    TxQueuedFrame &f = q.frames[q.tail];
    f.id  = ext_id;
    f.dlc = dlc;
    if (dlc > 0U) {
        memcpy(f.data, data, dlc);
    }
    q.tail = static_cast<uint8_t>((q.tail + 1U) % kTxQueueDepth);
    q.count++;

    NVIC_EnableIRQ(irqn);
    return CanTxResult::kOk;
}

/**
 * @brief CAN TX 完成中断末尾调用：用硬件邮箱空闲出的位置，把队列里的帧装回去。
 * @note  只在 ISR 内调用；关中断保护已在 transmitFrame 返回值判定外层完成，
 *        本函数本身不关中（邮箱空位是"单调减少再单调增加"，多读无害）。
 */
void CanFd::drainTxQueueIsr(uint8_t channelIndex)
{
    if (channelIndex >= kChannelCount) {
        return;
    }
    TxQueue &q = s_txQueues[channelIndex];
    while (q.count > 0U) {
        TxQueuedFrame &f = q.frames[q.head];
        /* 复用 transmitFrame 的装载逻辑；allow_abort=false：这里邮箱刚空出来，
         * 必能装上，禁止 abort 其它 PENDING 邮箱（会静默丢弃同通道排队帧）。 */
        const CanTxResult r = transmitFrame(channelIndex, f.id, f.data, f.dlc, false, false);
        if (r == CanTxResult::kOk) {
            q.head = static_cast<uint8_t>((q.head + 1U) % kTxQueueDepth);
            q.count--;
        } else {
            /* kErrMailbox：理论上不该发生（刚刚空出一个邮箱），保守 break；
             * 其它错误（kErrInvalid）已经入队又因参数错必败，直接丢弃防死循环。 */
            if (r != CanTxResult::kErrMailbox) {
                q.head = static_cast<uint8_t>((q.head + 1U) % kTxQueueDepth);
                q.count--;
            } else {
                break;
            }
        }
    }
}

uint32_t CanFd::txQueueBacklog(uint8_t channelIndex)
{
    if (channelIndex >= kChannelCount) {
        return 0U;
    }
    return s_txQueues[channelIndex].count;
}

void CanFd::abortPendingTx(uint8_t channelIndex)
{
    if (channelIndex >= kChannelCount || !kChannelEnabled[channelIndex]) {
        return;
    }
    const uint32_t canPeriph = kChannels[channelIndex].canPeriph;
    for (uint8_t mb = CAN_MAILBOX0; mb <= CAN_MAILBOX2; ++mb) {
        if (can_transmit_states(canPeriph, mb) == CAN_TRANSMIT_PENDING) {
            (void)can_transmission_stop(canPeriph, mb);
        }
    }
}

void CanFd::setChannelAutoRetrans(uint8_t channelIndex, bool enable)
{
    if (channelIndex >= kChannelCount || !kChannelEnabled[channelIndex]) {
        return;
    }
    const uint32_t canPeriph = kChannels[channelIndex].canPeriph;
    /* ARD 位仅在 init mode 可写：进 init mode → 改 ARD → 退 init mode。 */
    CAN_CTL(canPeriph) |= CAN_CTL_IWMOD;
    for (volatile uint32_t t = 0U; t < 200000U; ++t) {
        if (CAN_STAT(canPeriph) & CAN_STAT_IWS) break;
    }
    if (enable) {
        CAN_CTL(canPeriph) &= ~CAN_CTL_ARD;  /* 自动重发 ON（业务默认） */
    } else {
        CAN_CTL(canPeriph) |= CAN_CTL_ARD;   /* 自动重发 OFF（单发，停等式 OTA 用） */
    }
    CAN_CTL(canPeriph) &= ~CAN_CTL_IWMOD;
    for (volatile uint32_t t = 0U; t < 200000U; ++t) {
        if ((CAN_STAT(canPeriph) & CAN_STAT_IWS) == 0U) break;
    }
    CAN_LOGI("[CAN] CH%u set auto_retrans=%u -> ARD=%u\r\n",
           (unsigned)channelIndex, (unsigned)enable,
           (CAN_CTL(canPeriph) & CAN_CTL_ARD) ? 1U : 0U);
}

uint32_t CanFd::readChannelErrorReg(uint8_t channelIndex)
{
    if (channelIndex >= kChannelCount || !kChannelEnabled[channelIndex]) {
        return 0U;
    }
    /* 单次寄存器读，供事件时刻（如 OTA ACK 超时）抓取总线错误状态；
     * 不走 1Hz refreshFeedbackSnapshot，避免采样混叠。 */
    return CAN_ERR(kChannels[channelIndex].canPeriph);
}

bool CanFd::consumeTxError(uint8_t channelIndex)
{
    if (channelIndex >= kChannelCount || !kChannelEnabled[channelIndex]) {
        return false;
    }
    if (!s_txErrorEvent[channelIndex]) {
        return false;
    }
    s_txErrorEvent[channelIndex] = false;
    return true;
}

/**
 * @brief 获取 CANFD 诊断统计信息只读指针。
 * @param[in]  无。
 * @param[out] 无。
 * @retval const CanFd::Diag* 返回内部诊断统计结构体只读指针。
 */
const CanFd::Diag *CanFd::diag()
{
    return &s_diag;
}

/**
 * @brief 透传式发送：按接收帧的原格式（标准/扩展、CAN-FD/经典、BRS/ESI、DLC）原样转发到目标 CAN 通道。
 * @param[in]  canPeriph 目标 CAN 外设实例。
 * @param[in]  rx        刚从 FIFO0 读出的接收帧。
 * @retval bool true 表示成功入队硬件邮箱；false 表示三个邮箱均忙且无法 abort 重投。
 * @note  仅供桥接模式在 RX0 中断中调用；非阻塞，与 transmitFrame 共用 abort+重投策略，时间占用控制在寄存器访问级别。
 */
static bool bridgeTransmitRaw(uint32_t canPeriph, const can_receive_message_struct &rx)
{
    can_trasnmit_message_struct tx_msg{};
    can_struct_para_init(CAN_TX_MESSAGE_STRUCT, &tx_msg);
    tx_msg.tx_ff   = rx.rx_ff;
    if (rx.rx_ff == CAN_FF_STANDARD) {
        tx_msg.tx_sfid = rx.rx_sfid;
    } else {
        tx_msg.tx_efid = rx.rx_efid;
    }
    tx_msg.tx_ft   = CAN_FT_DATA;
    tx_msg.tx_dlen = rx.rx_dlen;
#ifdef GD32E508
    tx_msg.fd_flag = rx.fd_flag;
#if (CONFIG_CAN_FD_BRS_ENABLE != 0)
    tx_msg.fd_brs  = rx.fd_brs;
#else
    tx_msg.fd_brs  = DISABLE;
#endif
    tx_msg.fd_esi  = rx.fd_esi;
#endif
    const uint8_t copyLen = (rx.rx_dlen <= 64U) ? rx.rx_dlen : 64U;
    for (uint8_t i = 0U; i < copyLen; ++i) {
        tx_msg.tx_data[i] = rx.rx_data[i];
    }

    uint8_t mailbox = can_message_transmit(canPeriph, &tx_msg);
    if (mailbox == CAN_NOMAILBOX) {
        for (uint8_t mb = CAN_MAILBOX0; mb <= CAN_MAILBOX2; ++mb) {
            if (can_transmit_states(canPeriph, mb) != CAN_TRANSMIT_PENDING) {
                continue;
            }
            if (can_transmission_stop(canPeriph, mb) == SUCCESS) {
                break;
            }
        }
        mailbox = can_message_transmit(canPeriph, &tx_msg);
    }
    return mailbox != CAN_NOMAILBOX;
}

/**
 * @brief 处理指定通道的 RX0 中断接收。
 * @param[in]  channelIndex 目标 CAN 通道索引（0/1/2）。
 * @param[out] 无。
 * @retval    无返回值。
 * @note      从对应控制器 FIFO0 循环取空所有待处理报文，更新诊断统计，写入该通道软件接收队列，并置位解析任务。
 */
void CanFd::handleRxInterrupt(uint8_t channelIndex)
{
    if(channelIndex >= kChannelCount || !kChannelEnabled[channelIndex]) return;
    const auto &ch = kChannels[channelIndex];

    const bool fifoFull = (can_interrupt_flag_get(ch.canPeriph, CAN_INT_FLAG_RFF0) != RESET);
    const bool fifoOverfull = (can_interrupt_flag_get(ch.canPeriph, CAN_INT_FLAG_RFO0) != RESET);
    if(fifoFull) {
        can_interrupt_flag_clear(ch.canPeriph, CAN_INT_FLAG_RFF0);
        s_diag.rx_fifo_full_count++;
    }
    if(fifoOverfull) {
        can_interrupt_flag_clear(ch.canPeriph, CAN_INT_FLAG_RFO0);
        s_diag.rx_fifo_overfull_count++;
    }

    bool hadTraffic = false;
    while(can_interrupt_flag_get(ch.canPeriph, CAN_INT_FLAG_RFL0) != RESET) {
        hadTraffic = true;

        can_receive_message_struct rx_message{};
        can_struct_para_init(CAN_RX_MESSAGE_STRUCT, &rx_message);
        can_message_receive(ch.canPeriph, CAN_FIFO0, &rx_message);

        s_diag.rx_count++;
        s_diag.last_rx_channel = channelIndex;
        s_diag.last_payload_length = rx_message.rx_dlen;
        s_diag.last_rx_fd_flag = rx_message.fd_flag;
        s_diag.last_rx_brs = rx_message.fd_brs;
        s_diag.last_rx_esi = rx_message.fd_esi;
        s_diag.last_rx_id = (rx_message.rx_ff == CAN_FF_STANDARD) ? rx_message.rx_sfid : rx_message.rx_efid;
        /* CAN0 桥接模式：将刚收到的原帧透传到 CAN1 与 CAN2，保留 11/29 位、FD、BRS、ESI。 */
        if (channelIndex == 0U && s_mode == Mode::kModeBridge0To12) {
            for (uint8_t bridgeCh = 1U; bridgeCh <= 2U; ++bridgeCh) {
                const uint32_t bridgePeriph = kChannels[bridgeCh].canPeriph;
                const bool ok = bridgeTransmitRaw(bridgePeriph, rx_message);
                if (ok) {
                    s_diag.last_tx_id      = s_diag.last_rx_id;
                    s_diag.last_tx_channel = bridgeCh;
                    s_diag.last_payload_length = rx_message.rx_dlen;
                } else {
                    s_diag.error_count++;
                    s_channelStats[bridgeCh].error_count++;
                }
            }
        }

        /* 维护每通道独立计数与最近一帧快照，用于 1Hz 反馈给 ESP32。 */
        auto &stats = s_channelStats[channelIndex];
        stats.rx_count++;
        stats.last_rx_id      = s_diag.last_rx_id;
        stats.last_rx_dlc     = rx_message.rx_dlen;
        stats.last_rx_fd_flag = rx_message.fd_flag;
        stats.last_rx_brs     = rx_message.fd_brs;
        stats.last_rx_esi     = rx_message.fd_esi;
        const uint8_t copyLen = (rx_message.rx_dlen < CANFD_FEEDBACK_LAST_DATA_MAX)
                                ? rx_message.rx_dlen : static_cast<uint8_t>(CANFD_FEEDBACK_LAST_DATA_MAX);
        for (uint8_t i = 0U; i < copyLen; ++i) {
            stats.last_rx_data[i] = rx_message.rx_data[i];
        }
        for (uint8_t i = copyLen; i < CANFD_FEEDBACK_LAST_DATA_MAX; ++i) {
            stats.last_rx_data[i] = 0U;
        }
        /* 维护每通道不重复 ID 快照表，用于 1Hz 分页拉取给 ESP32。 */
        {
            auto &table = s_idSnapshot[channelIndex];
            const uint32_t rxId = s_diag.last_rx_id;
            /* 查找已有条目 */
            uint8_t found = CANFD_ID_SNAPSHOT_MAX;
            for (uint8_t si = 0U; si < table.count; ++si) {
                if (table.entries[si].occupied && table.entries[si].id == rxId) {
                    found = si;
                    break;
                }
            }
            if (found >= CANFD_ID_SNAPSHOT_MAX) {
                /* 未找到：表未满则新建，满了淘汰最旧（index 0） */
                if (table.count < CANFD_ID_SNAPSHOT_MAX) {
                    found = table.count;
                    table.count++;
                } else {
                    found = 0U;
                    /* 淘汰后整体左移一格让新条目在末尾 */
                    for (uint8_t si = 0U; si < CANFD_ID_SNAPSHOT_MAX - 1U; ++si) {
                        table.entries[si] = table.entries[si + 1U];
                    }
                    found = CANFD_ID_SNAPSHOT_MAX - 1U;
                }
                table.entries[found] = {};
                table.entries[found].id = rxId;
                table.entries[found].occupied = true;
            }
            auto &entry = table.entries[found];
            entry.rx_count++;
            entry.dlc     = rx_message.rx_dlen;
            entry.fd_flag = rx_message.fd_flag;
            entry.brs     = rx_message.fd_brs;
            entry.esi     = rx_message.fd_esi;
            const uint8_t snapCopy = (rx_message.rx_dlen < CANFD_ID_SNAPSHOT_DATA_MAX)
                                     ? rx_message.rx_dlen : static_cast<uint8_t>(CANFD_ID_SNAPSHOT_DATA_MAX);
            for (uint8_t si = 0U; si < snapCopy; ++si) {
                entry.data[si] = rx_message.rx_data[si];
            }
            for (uint8_t si = snapCopy; si < CANFD_ID_SNAPSHOT_DATA_MAX; ++si) {
                entry.data[si] = 0U;
            }
        }

        auto &queue = s_rxQueues[channelIndex];
        if(queue.count >= kRxQueueDepth) {
            s_diag.rx_drop_count++;
            stats.rx_drop_count++;
            continue;
        }

        auto &frame = queue.frames[queue.tail];
        frame.channel = channelIndex;
        frame.id = s_diag.last_rx_id;
        frame.length = rx_message.rx_dlen;
        for(uint8_t i = 0; i < rx_message.rx_dlen; ++i) {
            frame.data[i] = rx_message.rx_data[i];
        }

        queue.tail = static_cast<uint8_t>((queue.tail + 1U) % kRxQueueDepth);
        queue.count++;
    }

    if(fifoFull) {
        can_interrupt_flag_clear(ch.canPeriph, CAN_INT_FLAG_RFF0);
    }
    if(fifoOverfull) {
        can_interrupt_flag_clear(ch.canPeriph, CAN_INT_FLAG_RFO0);
    }
    if(hadTraffic) {
        TaskManager::set(kCanRxParseTaskMask);
    }
}

/**
 * @brief 处理指定通道的发送完成中断。
 * @param[in] channelIndex 目标 CAN 通道索引（0/1/2）。
 * @note  只有 MTFNERR 置位才表示完整发送且未出错；邮箱受理、仲裁丢失、
 *        主动中止和发送错误均不能计入网页“发送数”。
 */
void CanFd::handleTxInterrupt(uint8_t channelIndex)
{
    if (channelIndex >= kChannelCount || !kChannelEnabled[channelIndex]) {
        return;
    }

    const uint32_t canPeriph = kChannels[channelIndex].canPeriph;
    const uint32_t tstat = CAN_TSTAT(canPeriph);
    constexpr uint32_t finishedBits[] = {
        CAN_TSTAT_MTF0, CAN_TSTAT_MTF1, CAN_TSTAT_MTF2
    };
    constexpr uint32_t successBits[] = {
        CAN_TSTAT_MTFNERR0, CAN_TSTAT_MTFNERR1, CAN_TSTAT_MTFNERR2
    };
    constexpr uint32_t errorBits[] = {
        CAN_TSTAT_MTE0, CAN_TSTAT_MTE1, CAN_TSTAT_MTE2
    };

    for (size_t mailbox = 0U; mailbox < 3U; ++mailbox) {
        if ((tstat & finishedBits[mailbox]) == 0U) {
            continue;
        }

        if ((tstat & successBits[mailbox]) != 0U) {
            s_diag.tx_count++;
            s_channelStats[channelIndex].tx_count++;
        } else if ((tstat & errorBits[mailbox]) != 0U) {
            s_diag.error_count++;
            s_channelStats[channelIndex].error_count++;
            /* ARD=1 单发模式下 MTE 置位 = 该帧已确认丢失；置事件标志供停等式
             * OTA 快速重发（免等 ACK 超时）。单写（ISR）单读清（主循环），无锁。 */
            s_txErrorEvent[channelIndex] = true;
        }
    }

    CAN_TSTAT(canPeriph) = tstat & (CAN_TSTAT_MTF0 | CAN_TSTAT_MTF1 | CAN_TSTAT_MTF2);

    /* 队列里有积压帧时，趁刚空出的邮箱位置回灌。必须在 TSTAT 清标志之后调，
     * 否则 transmitFrame 看到的还是旧 PENDING 状态。 */
    drainTxQueueIsr(channelIndex);
}

/**
 * @brief 刷新三路 CAN 通道的 1Hz 反馈快照。
 * @note  在临界区内拷贝实时计数与最近一帧信息到 s_feedback；保证 SPI 命令读到一致快照。
 *        典型调用频率 1Hz，由任务调度器在心跳节拍触发。
 */
void CanFd::refreshFeedbackSnapshot()
{
    /* 先在临界区内采集硬件寄存器，确保三通道快照一致 */
    uint32_t hw_tec[3] = {};
    uint32_t hw_rec[3] = {};
    uint32_t hw_stat[3] = {};
    uint32_t hw_err[3] = {};
    uint32_t hw_rfl0[3] = {};
    {
        uint32_t save = RT_CRITICAL_SAVE();
        for (size_t i = 0; i < kChannelCount; ++i) {
            const auto &ch = kChannels[i];
            const uint32_t err_val = CAN_ERR(ch.canPeriph);
            const uint32_t stat_val = CAN_STAT(ch.canPeriph);
            hw_tec[i]  = (err_val >> 16) & 0xFFU;
            hw_rec[i]  = (err_val >> 24) & 0xFFU;
            hw_stat[i] = stat_val;
            hw_err[i]  = err_val;
            hw_rfl0[i] = can_receive_message_length_get(ch.canPeriph, CAN_FIFO0);
        }
        RT_CRITICAL_RESTORE(save);
    }

    s_feedbackSeq++;
    /* 每 5 秒采样硬件错误态；正常心跳不打印（统计走 SPI 0xC1）。
     * 仅当 TEC/REC 或告警位非零时输出 [CAN-HW-ERR]；全量 seq 心跳见 CONFIG_UART_DIAG_LEVEL。 */
    if (s_feedbackSeq % 5U == 0U) {
#if (CONFIG_UART_DIAG_LEVEL != 0)
        CAN_LOGI("[CAN-FB] refresh seq=%lu rx0=%lu rx1=%lu rx2=%lu\r\n",
               (unsigned long)s_feedbackSeq,
               (unsigned long)s_channelStats[0].rx_count,
               (unsigned long)s_channelStats[1].rx_count,
               (unsigned long)s_channelStats[2].rx_count);
#endif
        for (size_t i = 0; i < kChannelCount; ++i) {
            if (hw_tec[i] == 0U && hw_rec[i] == 0U
                && (hw_err[i] & (CAN_ERR_WERR | CAN_ERR_PERR | CAN_ERR_BOERR)) == 0U) {
                continue;
            }
            LOG_ERR("[CAN-HW-ERR] CH%u ERR=0x%08lX ERRN=%lu(%s) TEC=%lu REC=%lu TSTAT=0x%08lX\r\n",
                   static_cast<unsigned>(i),
                   static_cast<unsigned long>(hw_err[i]),
                   static_cast<unsigned long>((hw_err[i] >> 4U) & 0x07U),
                   canLastErrorName(hw_err[i]),
                   static_cast<unsigned long>(hw_tec[i]),
                   static_cast<unsigned long>(hw_rec[i]),
                   static_cast<unsigned long>(CAN_TSTAT(kChannels[i].canPeriph)));
        }
    }
    for (size_t i = 0; i < kChannelCount; ++i) {
        s_feedback[i].snapshot_seq = s_feedbackSeq;
        s_feedback[i].stats = s_channelStats[i];
        /* 写入硬件层错误状态供 SPI 反馈使用 */
        s_feedback[i].stats.tec = static_cast<uint8_t>(hw_tec[i]);
        s_feedback[i].stats.rec = static_cast<uint8_t>(hw_rec[i]);
        /* 总线状态位图：bit0=init, bit1=sleep, bit2=error_passive, bit3=bus_off, bit4=error_warning
         * init/sleep 来自 CAN_STAT，error_passive/bus_off/error_warning 来自 CAN_ERR */
        uint8_t busState = 0U;
        if (hw_stat[i] & CAN_STAT_IWS)  busState |= (1U << 0);  /* 初始化模式 */
        if (hw_stat[i] & CAN_STAT_SLPWS) busState |= (1U << 1);  /* 睡眠模式 */
        if (hw_err[i] & CAN_ERR_PERR)   busState |= (1U << 2);   /* 错误被动 */
        if (hw_err[i] & CAN_ERR_BOERR)  busState |= (1U << 3);   /* 总线关闭 */
        if (hw_err[i] & CAN_ERR_WERR)   busState |= (1U << 4);   /* 错误警告 */
        s_feedback[i].stats.bus_state = busState;
        s_idSnapshot[i].seq = s_feedbackSeq;
    }

    /* BUS_OFF 状态变化检测：仅在状态切换时打印，避免刷屏 */
    static uint8_t s_prevBusState[3] = {0xFF, 0xFF, 0xFF};  /* 0xFF=首次 */
    for (size_t i = 0; i < kChannelCount; ++i) {
        uint8_t cur = s_feedback[i].stats.bus_state;
        if (cur != s_prevBusState[i]) {
            const char *stateStr = "NORMAL";
            if (cur & (1U << 0)) stateStr = "INIT_MODE";
            else if (cur & (1U << 3)) stateStr = "BUS_OFF";
            else if (cur & (1U << 2)) stateStr = "ERR_PASSIVE";
            else if (cur & (1U << 4)) stateStr = "ERR_WARN";
            LOG_ERR("[CAN-BUS] CH%u: %s -> %s ERR=0x%08lX ERRN=%lu(%s) TEC=%lu REC=%lu seq=%lu\r\n",
                   static_cast<unsigned>(i),
                   (s_prevBusState[i] == 0xFF) ? "?" :
                   (s_prevBusState[i] & (1U << 3)) ? "BUS_OFF" :
                   (s_prevBusState[i] & (1U << 2)) ? "ERR_PASSIVE" :
                   (s_prevBusState[i] & (1U << 4)) ? "ERR_WARN" : "NORMAL",
                   stateStr,
                   static_cast<unsigned long>(hw_err[i]),
                   static_cast<unsigned long>((hw_err[i] >> 4U) & 0x07U),
                   canLastErrorName(hw_err[i]),
                   static_cast<unsigned long>(hw_tec[i]),
                   static_cast<unsigned long>(hw_rec[i]),
                   static_cast<unsigned long>(s_feedbackSeq));
            s_prevBusState[i] = cur;
        }
    }
}

/**
 * @brief 拷贝指定通道的最新反馈快照。
 * @param[in]  channelIndex 目标 CAN 通道号（0/1/2）。
 * @param[out] out          目标快照缓冲；为空或通道非法时返回 false。
 * @retval bool true 表示成功拷贝。
 */

/**
 * @brief 拷贝指定通道的不重复 ID 快照表。
 */
bool CanFd::copyIdSnapshotTable(uint8_t channelIndex, IdSnapshotTable *out)
{
    if (out == nullptr || channelIndex >= kChannelCount) {
        return false;
    }
    uint32_t save = RT_CRITICAL_SAVE();
    *out = s_idSnapshot[channelIndex];
    RT_CRITICAL_RESTORE(save);
    return true;
}
bool CanFd::copyFeedbackSnapshot(uint8_t channelIndex, ChannelFeedback *out)
{
    if (out == nullptr || channelIndex >= kChannelCount) {
        return false;
    }
    uint32_t save = RT_CRITICAL_SAVE();
    *out = s_feedback[channelIndex];
    RT_CRITICAL_RESTORE(save);
    return true;
}
/* ----- 中断入口 C 包装 ------------------------------------------------- */
/**
 * @brief CAN0 RX0 中断向量入口。
 * @param[in]  无。
 * @param[out] 无。
 * @retval    无返回值。
 * @note      C 向量包装函数，内部转调 `CanFd::handleRxInterrupt(0U)`。
 */
extern "C" void CAN0_RX0_IRQHandler(void)
{ CpuLoad::isrEnter(); CanFd::handleRxInterrupt(0U); CpuLoad::isrExit(); }

/** @brief CAN0 TX 完成中断向量入口。 */
extern "C" void CAN0_TX_IRQHandler(void)
{ CpuLoad::isrEnter(); CanFd::handleTxInterrupt(0U); CpuLoad::isrExit(); }

/**
 * @brief CAN1 RX0 中断向量入口。
 * @param[in]  无。
 * @param[out] 无。
 * @retval    无返回值。
 * @note      C 向量包装函数，内部转调 `CanFd::handleRxInterrupt(1U)`。
 */
extern "C" void CAN1_RX0_IRQHandler(void)
{ CpuLoad::isrEnter(); CanFd::handleRxInterrupt(1U); CpuLoad::isrExit(); }

/** @brief CAN1 TX 完成中断向量入口。 */
extern "C" void CAN1_TX_IRQHandler(void)
{ CpuLoad::isrEnter(); CanFd::handleTxInterrupt(1U); CpuLoad::isrExit(); }

/**
 * @brief CAN2 RX0 中断向量入口。
 * @param[in]  无。
 * @param[out] 无。
 * @retval    无返回值。
 * @note      C 向量包装函数，内部转调 `CanFd::handleRxInterrupt(2U)`。
 */
extern "C" void CAN2_RX0_IRQHandler(void)
{ CpuLoad::isrEnter(); CanFd::handleRxInterrupt(2U); CpuLoad::isrExit(); }

/** @brief CAN2 TX 完成中断向量入口。 */
extern "C" void CAN2_TX_IRQHandler(void)
{ CpuLoad::isrEnter(); CanFd::handleTxInterrupt(2U); CpuLoad::isrExit(); }