rt-thread H7 使用fdcan没有外接设备时或发送错误时线程被挂起的解决方案_业界新闻

发布时间:2024-08-03 06:11

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一、问题查找
使用的开发版是硬石的H7芯片型号STM32H743IIT6，测试时发现如果外面没有连接CAN设备，程序调用CAN发送时会一直等待发送反馈，导致相关线程挂起。
在线仿真时发现是卡在can.c文件的168行_can_int_tx函数：rt_completion_wait(&(tx_tosnd->completion), RT_WAITING_FOREVER);
代码如下：

rt_inline int _can_int_tx(struct rt_can_device *can, const struct rt_can_msg *data, int msgs) { 	int size; 	struct rt_can_tx_fifo *tx_fifo; 	RT_ASSERT(can != RT_NULL); 	size = msgs; 	tx_fifo = (struct rt_can_tx_fifo *) can->can_tx; 	RT_ASSERT(tx_fifo != RT_NULL); 	while (msgs) 	{ 		rt_base_t level; 		rt_uint32_t no; 		rt_uint32_t result; 		struct rt_can_sndbxinx_list tx_tosnd = RT_NULL; 		rt_sem_take(&(tx_fifo->sem), RT_WAITING_FOREVER); 		level = rt_hw_interrupt_disable(); 		tx_tosnd = rt_list_entry(tx_fifo->freelist.next, struct rt_can_sndbxinx_list, list); 		RT_ASSERT(tx_tosnd != RT_NULL); 		rt_list_remove(&tx_tosnd->list); 		rt_hw_interrupt_enable(level); 		no = ((rt_uint32_t)tx_tosnd - (rt_uint32_t)tx_fifo->buffer) / sizeof(struct rt_can_sndbxinx_list); 		tx_tosnd->result = RT_CAN_SND_RESULT_WAIT; 		if (can->ops->sendmsg(can, data, no) != RT_EOK) 		{ 			/ send failed. */ 			level = rt_hw_interrupt_disable(); 			rt_list_insert_after(&tx_fifo->freelist, &tx_tosnd->list); 			rt_hw_interrupt_enable(level); 			rt_sem_release(&(tx_fifo->sem)); 			continue; 		} 		can->status.sndchange = 1; 		rt_completion_wait(&(tx_tosnd->completion), RT_WAITING_FOREVER);

说明一直在等待完成信号，而发送完成信号的地方在can.c文件的900行rt_hw_can_isr函数：rt_completion_done(&(tx_fifo->buffer[no].completion));
源码如下：

case RT_CAN_EVENT_TX_DONE: case RT_CAN_EVENT_TX_FAIL: {     struct rt_can_tx_fifo *tx_fifo;     rt_uint32_t no;     no = event > > 8;     tx_fifo = (struct rt_can_tx_fifo *) can- >can_tx;     RT_ASSERT(tx_fifo != RT_NULL);     if ((event & 0xff) == RT_CAN_EVENT_TX_DONE)     {         tx_fifo- >buffer[no].result = RT_CAN_SND_RESULT_OK;     }     else     {         tx_fifo- >buffer[no].result = RT_CAN_SND_RESULT_ERR;     }     rt_completion_done(&(tx_fifo- >buffer[no].completion));     break; }

二、解决方案
看完can的驱动源码后想到如果can总线没有其他设备，CAN发送报文应该属于出错的情况，查看drv_fdcan.c文件中关于几种中断的处理，发现故障后的回调函数里没有调用rt_hw_can_isr。于是参考HAL_FDCAN_TxBufferCompleteCallback函数的处理方式，对HAL_FDCAN_ErrorCallback进行了如下处理。
源码如下：

void HAL_FDCAN_ErrorCallback(FDCAN_HandleTypeDef *hfdcan) { 	rt_uint32_t tmp_u32Errcount; 	rt_uint32_t tmp_u32status; 	uint32_t ret = HAL_FDCAN_GetError(hfdcan); 	if(hfdcan->Instance == FDCAN1) 	{ 		#ifdef BSP_USING_FDCAN1 		//can1 		if( (ret & FDCAN_IT_ARB_PROTOCOL_ERROR) && 		(hfdcan->Instance->CCCR & FDCAN_CCCR_INIT_Msk)) 		{ 			//hfdcan->Instance->CCCR |= FDCAN_CCCR_CCE_Msk; 			hfdcan->Instance->CCCR &= ~FDCAN_CCCR_INIT_Msk; 			st_DrvCan1.device.status.errcode = 0xff; 		} 		else 		{ 			tmp_u32Errcount = st_DrvCan1.fdcanHandle.Instance->ECR; 			tmp_u32status = st_DrvCan1.fdcanHandle.Instance->PSR; 			st_DrvCan1.device.status.rcverrcnt = (tmp_u32Errcount>>8)&0x000000ff; 			st_DrvCan1.device.status.snderrcnt = (tmp_u32Errcount)&0x000000ff; 			st_DrvCan1.device.status.lasterrtype = tmp_u32status&0x000000007; 			rt_hw_can_isr(&st_DrvCan1.device, RT_CAN_EVENT_TX_FAIL); 		} 		#endif / BSP_USING_FDCAN1 / 	} 	else 	{ 		#ifdef BSP_USING_FDCAN2 		if( (ret & FDCAN_IT_ARB_PROTOCOL_ERROR) && 		(hfdcan->Instance->CCCR & FDCAN_CCCR_INIT_Msk)) 		{ 			//hfdcan->Instance->CCCR |= FDCAN_CCCR_CCE_Msk; 			hfdcan->Instance->CCCR &= ~FDCAN_CCCR_INIT_Msk; 			st_DrvCan2.device.status.errcode = 0xff; 		} 		else 		{ 			//can2 			tmp_u32Errcount = st_DrvCan2.fdcanHandle.Instance->ECR; 			tmp_u32status = st_DrvCan2.fdcanHandle.Instance->PSR; 			st_DrvCan2.device.status.rcverrcnt = (tmp_u32Errcount>>8)&0x000000ff; 			st_DrvCan2.device.status.snderrcnt = (tmp_u32Errcount)&0x000000ff; 			st_DrvCan2.device.status.lasterrtype = tmp_u32status&0x000000007; 			rt_hw_can_isr(&st_DrvCan2.device, RT_CAN_EVENT_TX_FAIL); 		} 		#endif / BSP_USING_FDCAN2 / 	} }