我用 STM32CubeMX 生成了工程，板子上的以太网通信在网线预先插好的情况下可以正常工作。

但存在一个问题：只有在开机时网线已经接好，以太网才能正常工作。如果板子上电时没有插网线，以太网就无法正常工作，即便之后再插上网线也始终无法恢复。

为了解决这个问题，我在 LWIP 初始化完成后添加了如下函数：

netif_set_link_callback(&gnetif, ethernetif_update_config);

其中ethernetif_update_config函数是 CubeMX 自动生成的，作用是重启以太网自动协商。

void

ethernetif_update_config(

struct

netif *netif)

{

__IO uint32_t tickstart = 0;

uint32_t regvalue = 0;

if

(netif_is_link_up(netif))

{

/ Restart the auto-negotiation /

if

(heth.Init.AutoNegotiation != ETH_AUTONEGOTIATION_DISABLE)

{

/ Enable Auto-Negotiation /

HAL_ETH_WritePHYRegister(&heth, PHY_BCR, PHY_AUTONEGOTIATION);

/ Get tick /

tickstart = HAL_GetTick();

/ Wait until the auto-negotiation will be completed /

do

{

HAL_ETH_ReadPHYRegister(&heth, PHY_BSR, ®value);

/ Check for the Timeout ( 1s ) /

if

((HAL_GetTick() - tickstart ) > 1000)

{

/ In case of timeout /

goto

error;

}

}

while

(((regvalue & PHY_AUTONEGO_COMPLETE) != PHY_AUTONEGO_COMPLETE));

/ Read the result of the auto-negotiation /

HAL_ETH_ReadPHYRegister(&heth, PHY_SR, ®value);

/ Configure the MAC with the Duplex Mode fixed by the auto-negotiation process /

if

((regvalue & PHY_DUPLEX_STATUS) != (uint32_t)RESET)

{

/ Set Ethernet duplex mode to Full-duplex following the auto-negotiation /

heth.Init.DuplexMode = ETH_MODE_FULLDUPLEX;

}

else

{

/ Set Ethernet duplex mode to Half-duplex following the auto-negotiation /

heth.Init.DuplexMode = ETH_MODE_HALFDUPLEX;

}

/ Configure the MAC with the speed fixed by the auto-negotiation process /

if

(regvalue & PHY_SPEED_STATUS)

{

/ Set Ethernet speed to 10M following the auto-negotiation /

heth.Init.Speed = ETH_SPEED_10M;

}

else

{

/ Set Ethernet speed to 100M following the auto-negotiation /

heth.Init.Speed = ETH_SPEED_100M;

}

}

else

/ AutoNegotiation Disable /

{

error :

/ Check parameters /

assert_param(IS_ETH_SPEED(heth.Init.Speed));

assert_param(IS_ETH_DUPLEX_MODE(heth.Init.DuplexMode));

/ Set MAC Speed and Duplex Mode to PHY /

HAL_ETH_WritePHYRegister(&heth, PHY_BCR, ((uint16_t)(heth.Init.DuplexMode >> 3) |

(uint16_t)(heth.Init.Speed >> 1)));

}

/ ETHERNET MAC Re-Configuration /

HAL_ETH_ConfigMAC(&heth, (ETH_MACInitTypeDef *) NULL);

/ Restart MAC interface /

HAL_ETH_Start(&heth);

}

else

{

/ Stop MAC interface /

HAL_ETH_Stop(&heth);

}

ethernetif_notify_conn_changed(netif);

}

我在插上网线后通过调用netif_set_link_up(&gnetif)手动触发该回调函数时，以太网依旧无法正常工作。有没有人知道在这种场景下该如何让以太网正常运行？