rt-thread+STM32H7移植lwip出现问题解决方法

问题一：ping不通，或有丢帧情况。
问题二：不开启优化一切正常，keil开启优化后就无法联网。
问题三：网络断断续续。

解决方法：
主要是mpu配置和drv_eth驱动的问题，我的配置如下：
mpu：

/** Copyright (c) 2006-2021, RT-Thread Development Team** SPDX-License-Identifier: Apache-2.0** Change Logs:* Date           Author       Notes* 2019-04-14     whj4674672   first version*/
#include <rtthread.h>
#include "stm32h7xx.h"int mpu_init(void)
{MPU_Region_InitTypeDef MPU_InitStruct;/* Disable the MPU */HAL_MPU_Disable();/* Configure the MPU attributes as WT for AXI SRAM */MPU_InitStruct.Enable            = MPU_REGION_ENABLE;MPU_InitStruct.BaseAddress       = 0x24000000;MPU_InitStruct.Size              = MPU_REGION_SIZE_512KB;MPU_InitStruct.AccessPermission  = MPU_REGION_FULL_ACCESS;MPU_InitStruct.IsBufferable      = MPU_ACCESS_NOT_BUFFERABLE;MPU_InitStruct.IsCacheable       = MPU_ACCESS_CACHEABLE;MPU_InitStruct.IsShareable       = MPU_ACCESS_NOT_SHAREABLE;MPU_InitStruct.Number            = MPU_REGION_NUMBER0;MPU_InitStruct.TypeExtField      = MPU_TEX_LEVEL0;MPU_InitStruct.SubRegionDisable  = 0X00;MPU_InitStruct.DisableExec       = MPU_INSTRUCTION_ACCESS_ENABLE;HAL_MPU_ConfigRegion(&MPU_InitStruct);#ifdef BSP_USING_SDRAM/* Configure the MPU attributes as WT for SDRAM */MPU_InitStruct.Enable            = MPU_REGION_ENABLE;MPU_InitStruct.BaseAddress       = 0xC0000000;MPU_InitStruct.Size              = MPU_REGION_SIZE_32MB;MPU_InitStruct.AccessPermission  = MPU_REGION_FULL_ACCESS;MPU_InitStruct.IsBufferable      = MPU_ACCESS_NOT_BUFFERABLE;MPU_InitStruct.IsCacheable       = MPU_ACCESS_CACHEABLE;MPU_InitStruct.IsShareable       = MPU_ACCESS_NOT_SHAREABLE;MPU_InitStruct.Number            = MPU_REGION_NUMBER1;MPU_InitStruct.TypeExtField      = MPU_TEX_LEVEL0;MPU_InitStruct.SubRegionDisable  = 0x00;MPU_InitStruct.DisableExec       = MPU_INSTRUCTION_ACCESS_ENABLE;HAL_MPU_ConfigRegion(&MPU_InitStruct);
#endif#ifdef BSP_USING_ETH/* Configure the MPU attributes as Device not cacheable for ETH DMA descriptors and RX Buffers*/MPU_InitStruct.Enable = MPU_REGION_ENABLE;MPU_InitStruct.BaseAddress = 0x30040000;MPU_InitStruct.Size = MPU_REGION_SIZE_256B;MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;MPU_InitStruct.IsBufferable = MPU_ACCESS_BUFFERABLE;MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;MPU_InitStruct.IsShareable = MPU_ACCESS_NOT_SHAREABLE;MPU_InitStruct.Number = MPU_REGION_NUMBER2;MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;MPU_InitStruct.SubRegionDisable = 0x00;MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;HAL_MPU_ConfigRegion(&MPU_InitStruct);MPU_InitStruct.Enable = MPU_REGION_ENABLE;MPU_InitStruct.BaseAddress = 0x30044000;MPU_InitStruct.Size = MPU_REGION_SIZE_16KB;MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;MPU_InitStruct.IsCacheable = MPU_ACCESS_CACHEABLE;MPU_InitStruct.IsShareable = MPU_ACCESS_NOT_SHAREABLE;MPU_InitStruct.Number = MPU_REGION_NUMBER3;MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;MPU_InitStruct.SubRegionDisable = 0x00;MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;HAL_MPU_ConfigRegion(&MPU_InitStruct);
#endif/* Enable the MPU */HAL_MPU_Enable(MPU_PRIVILEGED_DEFAULT);/* Enable CACHE */SCB_EnableICache();SCB_EnableDCache();return 0;}
INIT_BOARD_EXPORT(mpu_init);

drv_eth.c

/** Copyright (c) 2006-2018, RT-Thread Development Team** SPDX-License-Identifier: Apache-2.0** Change Logs:* Date           Author       Notes* 2018-11-19     SummerGift   first version* 2018-12-25     zylx         fix some bugs* 2019-06-10     SummerGift   optimize PHY state detection process* 2019-09-03     xiaofan      optimize link change detection process* 2020-07-17     wanghaijing  support h7* 2020-11-30     wanghaijing  add phy reset*/#include<rtthread.h>
#include<rtdevice.h>
#include "board.h"
#include "drv_config.h"
#include <string.h>#ifdef BSP_USING_ETH#include <netif/ethernetif.h>
#include "lwipopts.h"
#include "drv_eth.h"/*
* Emac driver uses CubeMX tool to generate emac and phy's configuration,
* the configuration files can be found in CubeMX_Config folder.
*//* debug option */
//#define ETH_RX_DUMP
//#define ETH_TX_DUMP
//#define DRV_DEBUG
#define LOG_TAG             "drv.emac"
#include <drv_log.h>#define MAX_ADDR_LEN 6struct rt_stm32_eth
{/* inherit from ethernet device */struct eth_device parent;
#ifndef PHY_USING_INTERRUPT_MODErt_timer_t poll_link_timer;
#endif/* interface address info, hw address */rt_uint8_t  dev_addr[MAX_ADDR_LEN];/* ETH_Speed */uint32_t    ETH_Speed;/* ETH_Duplex_Mode */uint32_t    ETH_Mode;
};static ETH_HandleTypeDef EthHandle;
static ETH_TxPacketConfig TxConfig;
static struct rt_stm32_eth stm32_eth_device;
static uint8_t PHY_ADDR = 0x1F;
static rt_uint32_t reset_pin = -1;#if defined ( __ICCARM__ ) /*!< IAR Compiler */
#pragma location=0x30040000
ETH_DMADescTypeDef  DMARxDscrTab[ETH_RX_DESC_CNT]; /* Ethernet Rx DMA Descriptors */
#pragma location=0x30040060
ETH_DMADescTypeDef  DMATxDscrTab[ETH_TX_DESC_CNT]; /* Ethernet Tx DMA Descriptors */
#pragma location=0x30040200
uint8_t Rx_Buff[ETH_RX_DESC_CNT][ETH_MAX_PACKET_SIZE]; /* Ethernet Receive Buffers */#elif defined ( __CC_ARM )  /* MDK ARM Compiler */
__attribute__((at(0x30040000))) ETH_DMADescTypeDef  DMARxDscrTab[ETH_RX_DESC_CNT]; /* Ethernet Rx DMA Descriptors */
__attribute__((at(0x30040060))) ETH_DMADescTypeDef  DMATxDscrTab[ETH_TX_DESC_CNT]; /* Ethernet Tx DMA Descriptors */
__attribute__((at(0x30040200))) uint8_t Rx_Buff[ETH_RX_DESC_CNT][ETH_MAX_PACKET_SIZE]; /* Ethernet Receive Buffer */#elif defined ( __GNUC__ ) /* GNU Compiler */
ETH_DMADescTypeDef DMARxDscrTab[ETH_RX_DESC_CNT] __attribute__((section(".ARM.__at_0x30040000"))); /* Ethernet Rx DMA Descriptors */
ETH_DMADescTypeDef DMATxDscrTab[ETH_TX_DESC_CNT] __attribute__((section(".ARM.__at_0x30040060")));   /* Ethernet Tx DMA Descriptors */
uint8_t Rx_Buff[ETH_RX_DESC_CNT][ETH_MAX_PACKET_SIZE] __attribute__((section(".ARM.__at_0x30040200"))); /* Ethernet Receive Buffers */
#endif#if defined(ETH_RX_DUMP) || defined(ETH_TX_DUMP)
#define __is_print(ch) ((unsigned int)((ch) - ' ') < 127u - ' ')
static void dump_hex(const rt_uint8_t *ptr, rt_size_t buflen)
{unsigned char *buf = (unsigned char *)ptr;int i, j;for (i = 0; i < buflen; i += 16){rt_kprintf("%08X: ", i);for (j = 0; j < 16; j++)if (i + j < buflen)rt_kprintf("%02X ", buf[i + j]);elsert_kprintf("   ");rt_kprintf(" ");for (j = 0; j < 16; j++)if (i + j < buflen)rt_kprintf("%c", __is_print(buf[i + j]) ? buf[i + j] : '.');rt_kprintf("\n");}
}
#endifstatic void phy_reset(void)
{rt_pin_write(reset_pin, PIN_LOW);rt_thread_mdelay(50);rt_pin_write(reset_pin, PIN_HIGH);
}HAL_StatusTypeDef LAN8720_Init(ETH_HandleTypeDef *heth)
{uint32_t phyreg = 0;uint32_t TIME_Out = 0;//软件复位LAN8720Aif(HAL_ETH_WritePHYRegister(heth, PHY_BASIC_CONTROL_REG, 0x00, 0x8000) != HAL_OK){return HAL_ERROR;}//等待LAN8720A复位完成HAL_Delay(0x00000F);if((HAL_ETH_WritePHYRegister(heth, PHY_BASIC_CONTROL_REG, 0x00, 0x1000)) != HAL_OK){return HAL_ERROR;   }     //等待LAN8720A写入完成HAL_Delay(0xF);do{     HAL_ETH_ReadPHYRegister(heth, PHY_BASIC_CONTROL_REG, 0x01, &phyreg);TIME_Out++;if(TIME_Out > 0x0000FFFF) return HAL_TIMEOUT;} while (((phyreg & 0x0020) != 0x0020));return HAL_OK;    
}
/* EMAC initialization function */
static rt_err_t rt_stm32_eth_init(rt_device_t dev)
{ETH_MACConfigTypeDef MACConf;uint32_t regvalue = 0;uint8_t  status = RT_EOK;__HAL_RCC_D2SRAM3_CLK_ENABLE();// phy_reset();/* ETHERNET Configuration */EthHandle.Instance = ETH;EthHandle.Init.MACAddr = (rt_uint8_t *)&stm32_eth_device.dev_addr[0];EthHandle.Init.MediaInterface = HAL_ETH_RMII_MODE;EthHandle.Init.TxDesc = DMATxDscrTab;EthHandle.Init.RxDesc = DMARxDscrTab;EthHandle.Init.RxBuffLen = ETH_MAX_PACKET_SIZE;SCB_InvalidateDCache();HAL_ETH_DeInit(&EthHandle);/* configure ethernet peripheral (GPIOs, clocks, MAC, DMA) */if (HAL_ETH_Init(&EthHandle) != HAL_OK){LOG_E("eth hardware init failed");}else{LOG_D("eth hardware init success");}rt_memset(&TxConfig, 0, sizeof(ETH_TxPacketConfig));TxConfig.Attributes   = ETH_TX_PACKETS_FEATURES_CSUM | ETH_TX_PACKETS_FEATURES_CRCPAD;TxConfig.ChecksumCtrl = ETH_CHECKSUM_IPHDR_PAYLOAD_INSERT_PHDR_CALC;TxConfig.CRCPadCtrl   = ETH_CRC_PAD_INSERT;for (int idx = 0; idx < ETH_RX_DESC_CNT; idx++){HAL_ETH_DescAssignMemory(&EthHandle, idx, &Rx_Buff[idx][0], NULL);}HAL_ETH_SetMDIOClockRange(&EthHandle);LAN8720_Init(&EthHandle);rt_thread_delay(200);for(int i = 0; i <= PHY_ADDR; i ++){if(HAL_ETH_ReadPHYRegister(&EthHandle, i, PHY_SPECIAL_MODES_REG, &regvalue) != HAL_OK){status = RT_ERROR;/* Can't read from this device address continue with next address */continue;}if((regvalue & PHY_BASIC_STATUS_REG) == i){PHY_ADDR = i;status = RT_EOK;LOG_D("Found a phy, address:0x%02X", PHY_ADDR);break;}}if(HAL_ETH_WritePHYRegister(&EthHandle, PHY_ADDR, PHY_BASIC_CONTROL_REG, PHY_RESET_MASK) == HAL_OK){HAL_ETH_ReadPHYRegister(&EthHandle, PHY_ADDR, PHY_SPECIAL_MODES_REG, &regvalue);uint32_t tickstart = rt_tick_get();/* wait until software reset is done or timeout occured  */while(regvalue & PHY_RESET_MASK){if((rt_tick_get() - tickstart) <= 500){if(HAL_ETH_ReadPHYRegister(&EthHandle, PHY_ADDR, PHY_BASIC_CONTROL_REG, &regvalue) != HAL_OK){status = RT_ERROR;break;}}else{status = RT_ETIMEOUT;}}}rt_thread_delay(2000);if(HAL_ETH_ReadPHYRegister(&EthHandle, PHY_ADDR, PHY_BASIC_CONTROL_REG, &regvalue) == HAL_OK){regvalue |= PHY_AUTO_NEGOTIATION_MASK;HAL_ETH_WritePHYRegister(&EthHandle, PHY_ADDR, PHY_BASIC_CONTROL_REG, regvalue);eth_device_linkchange(&stm32_eth_device.parent, RT_TRUE);HAL_ETH_GetMACConfig(&EthHandle, &MACConf);MACConf.DuplexMode = ETH_FULLDUPLEX_MODE;MACConf.Speed = ETH_SPEED_100M;HAL_ETH_SetMACConfig(&EthHandle, &MACConf);HAL_ETH_Start_IT(&EthHandle);}else{status = RT_ERROR;}return status;
}static rt_err_t rt_stm32_eth_open(rt_device_t dev, rt_uint16_t oflag)
{LOG_D("emac open");return RT_EOK;
}static rt_err_t rt_stm32_eth_close(rt_device_t dev)
{LOG_D("emac close");return RT_EOK;
}static rt_ssize_t rt_stm32_eth_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
{LOG_D("emac read");rt_set_errno(-RT_ENOSYS);return 0;
}static rt_ssize_t rt_stm32_eth_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
{LOG_D("emac write");rt_set_errno(-RT_ENOSYS);return 0;
}static rt_err_t rt_stm32_eth_control(rt_device_t dev, int cmd, void *args)
{switch (cmd){case NIOCTL_GADDR:/* get mac address */if (args) rt_memcpy(args, stm32_eth_device.dev_addr, 6);else return -RT_ERROR;break;default :break;}return RT_EOK;
}/* ethernet device interface */
/* transmit data*/
rt_err_t rt_stm32_eth_tx(rt_device_t dev, struct pbuf *p)
{rt_err_t ret = RT_ERROR;HAL_StatusTypeDef state;uint32_t i = 0, framelen = 0;struct pbuf *q;ETH_BufferTypeDef Txbuffer[ETH_TX_DESC_CNT];rt_memset(Txbuffer, 0, ETH_TX_DESC_CNT * sizeof(ETH_BufferTypeDef));for (q = p; q != NULL; q = q->next){if (i >= ETH_TX_DESC_CNT)return ERR_IF;Txbuffer[i].buffer = q->payload;Txbuffer[i].len = q->len;framelen += q->len;if (i > 0){Txbuffer[i - 1].next = &Txbuffer[i];}if (q->next == NULL){Txbuffer[i].next = NULL;}i++;}TxConfig.Length = framelen;TxConfig.TxBuffer = Txbuffer;#ifdef ETH_TX_DUMPrt_kprintf("Tx dump, len= %d\r\n", framelen);dump_hex(Txbuffer[0].buffer,framelen);
#endifif (stm32_eth_device.parent.link_status){SCB_CleanInvalidateDCache();state = HAL_ETH_Transmit(&EthHandle, &TxConfig, 1000);if (state != HAL_OK){LOG_W("eth transmit frame faild: %d", EthHandle.ErrorCode);EthHandle.ErrorCode = HAL_ETH_STATE_READY;EthHandle.gState = HAL_ETH_STATE_READY;}}else{LOG_E("eth transmit frame faild, netif not up");}ret = ERR_OK;return ret;
}/* receive data*/
struct pbuf *rt_stm32_eth_rx(rt_device_t dev)
{uint32_t framelength = 0;rt_uint16_t l;struct pbuf *p = RT_NULL, *q;ETH_BufferTypeDef RxBuff;uint32_t alignedAddr;if(HAL_ETH_GetRxDataBuffer(&EthHandle, &RxBuff) == HAL_OK){HAL_ETH_GetRxDataLength(&EthHandle, &framelength);/* Build Rx descriptor to be ready for next data reception */HAL_ETH_BuildRxDescriptors(&EthHandle);/* Invalidate data cache for ETH Rx Buffers */alignedAddr = (uint32_t)RxBuff.buffer & ~0x1F;SCB_InvalidateDCache_by_Addr((uint32_t *)alignedAddr, (uint32_t)RxBuff.buffer - alignedAddr + framelength);p = pbuf_alloc(PBUF_RAW, framelength, PBUF_RAM);if (p != NULL){for (q = p, l = 0; q != NULL; q = q->next){memcpy((rt_uint8_t *)q->payload, (rt_uint8_t *)&RxBuff.buffer[l], q->len);l = l + q->len;}}}return p;
}/* interrupt service routine */
void ETH_IRQHandler(void)
{/* enter interrupt */rt_interrupt_enter();HAL_ETH_IRQHandler(&EthHandle);/* leave interrupt */rt_interrupt_leave();
}void HAL_ETH_RxCpltCallback(ETH_HandleTypeDef *heth)
{rt_err_t result;result = eth_device_ready(&(stm32_eth_device.parent));if (result != RT_EOK)LOG_I("RxCpltCallback err = %d", result);
}void HAL_ETH_ErrorCallback(ETH_HandleTypeDef *heth)
{LOG_E("eth err");
}enum {PHY_LINK        = (1 << 0),PHY_100M        = (1 << 1),PHY_FULL_DUPLEX = (1 << 2),
};static void phy_linkchange()
{static rt_uint8_t phy_speed = 0;rt_uint8_t phy_speed_new = 0;rt_uint32_t status;HAL_ETH_ReadPHYRegister(&EthHandle, PHY_ADDR, PHY_BASIC_STATUS_REG, (uint32_t *)&status);LOG_D("phy basic status reg is 0x%X", status);if (status & (PHY_AUTONEGO_COMPLETE_MASK | PHY_LINKED_STATUS_MASK)){rt_uint32_t SR = 0;phy_speed_new |= PHY_LINK;HAL_ETH_ReadPHYRegister(&EthHandle, PHY_ADDR, PHY_Status_REG, (uint32_t *)&SR);LOG_D("phy control status reg is 0x%X", SR);if (PHY_Status_SPEED_100M(SR)){phy_speed_new |= PHY_100M;}if (PHY_Status_FULL_DUPLEX(SR)){phy_speed_new |= PHY_FULL_DUPLEX;}}if (phy_speed != phy_speed_new){phy_speed = phy_speed_new;if (phy_speed & PHY_LINK){LOG_D("link up");if (phy_speed & PHY_100M){LOG_D("100Mbps");stm32_eth_device.ETH_Speed = ETH_SPEED_100M;}else{stm32_eth_device.ETH_Speed = ETH_SPEED_10M;LOG_D("10Mbps");}if (phy_speed & PHY_FULL_DUPLEX){LOG_D("full-duplex");stm32_eth_device.ETH_Mode = ETH_FULLDUPLEX_MODE;}else{LOG_D("half-duplex");stm32_eth_device.ETH_Mode = ETH_HALFDUPLEX_MODE;}/* send link up. */eth_device_linkchange(&stm32_eth_device.parent, RT_TRUE);}else{LOG_I("link down");eth_device_linkchange(&stm32_eth_device.parent, RT_FALSE);}}
}#ifdef PHY_USING_INTERRUPT_MODE
static void eth_phy_isr(void *args)
{rt_uint32_t status = 0;HAL_ETH_ReadPHYRegister(&EthHandle, PHY_ADDR, PHY_INTERRUPT_FLAG_REG, (uint32_t *)&status);LOG_D("phy interrupt status reg is 0x%X", status);phy_linkchange();
}
#endif /* PHY_USING_INTERRUPT_MODE */static void phy_monitor_thread_entry(void *parameter)
{phy_linkchange();
#ifdef PHY_USING_INTERRUPT_MODE/* configuration intterrupt pin */rt_pin_mode(PHY_INT_PIN, PIN_MODE_INPUT_PULLUP);rt_pin_attach_irq(PHY_INT_PIN, PIN_IRQ_MODE_FALLING, eth_phy_isr, (void *)"callbackargs");rt_pin_irq_enable(PHY_INT_PIN, PIN_IRQ_ENABLE);/* enable phy interrupt */HAL_ETH_WritePHYRegister(&EthHandle, PHY_ADDR, PHY_INTERRUPT_MASK_REG, PHY_INT_MASK);
#if defined(PHY_INTERRUPT_CTRL_REG)HAL_ETH_WritePHYRegister(&EthHandle, PHY_ADDR, PHY_INTERRUPT_CTRL_REG, PHY_INTERRUPT_EN);
#endif
#else /* PHY_USING_INTERRUPT_MODE */stm32_eth_device.poll_link_timer = rt_timer_create("phylnk", (void (*)(void*))phy_linkchange,NULL, RT_TICK_PER_SECOND, RT_TIMER_FLAG_PERIODIC);if (!stm32_eth_device.poll_link_timer || rt_timer_start(stm32_eth_device.poll_link_timer) != RT_EOK){LOG_E("Start link change detection timer failed");}
#endif /* PHY_USING_INTERRUPT_MODE */
}/* Register the EMAC device */
static int rt_hw_stm32_eth_init(void)
{rt_err_t state = RT_EOK;rt_pin_mode(reset_pin, PIN_MODE_OUTPUT);rt_pin_write(reset_pin, PIN_HIGH);stm32_eth_device.ETH_Speed = ETH_SPEED_100M;stm32_eth_device.ETH_Mode = ETH_FULLDUPLEX_MODE;/* OUI 00-80-E1 STMICROELECTRONICS. */stm32_eth_device.dev_addr[0] = 0x00;stm32_eth_device.dev_addr[1] = 0x80;stm32_eth_device.dev_addr[2] = 0xE1;/* generate MAC addr from 96bit unique ID (only for test). */stm32_eth_device.dev_addr[3] = *(rt_uint8_t *)(UID_BASE + 4);stm32_eth_device.dev_addr[4] = *(rt_uint8_t *)(UID_BASE + 2);stm32_eth_device.dev_addr[5] = *(rt_uint8_t *)(UID_BASE + 0);stm32_eth_device.parent.parent.init      = rt_stm32_eth_init;stm32_eth_device.parent.parent.open      = rt_stm32_eth_open;stm32_eth_device.parent.parent.close     = rt_stm32_eth_close;stm32_eth_device.parent.parent.read      = rt_stm32_eth_read;stm32_eth_device.parent.parent.write     = rt_stm32_eth_write;stm32_eth_device.parent.parent.control   = rt_stm32_eth_control;stm32_eth_device.parent.parent.user_data = RT_NULL;stm32_eth_device.parent.eth_rx = rt_stm32_eth_rx;stm32_eth_device.parent.eth_tx = rt_stm32_eth_tx;/* register eth device */state = eth_device_init(&(stm32_eth_device.parent), "e0");if (RT_EOK == state){LOG_D("emac device init success");}else{LOG_E("emac device init faild: %d", state);state = -RT_ERROR;}/* start phy monitor */rt_thread_t tid;tid = rt_thread_create("phy",phy_monitor_thread_entry,RT_NULL,2048,2,2);if (tid != RT_NULL){rt_thread_startup(tid);}else{state = -RT_ERROR;}return state;
}
INIT_DEVICE_EXPORT(rt_hw_stm32_eth_init);#endif /* BSP_USING_ETH */

我采用的是软件复位。