本文主要是介绍STM32用flash保存参数实现平衡擦写的一种方法，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
#FLASH平衡擦写#
一、概述
简易示意图如下：
写参数前要擦除对应的扇区 全为0XFFFFFFFF操作的最小单位为32位 uint32_t; 当一块扇区写完时，将所有有用参数复制到第二块扇区，开始写新的参数，如果所有参数写完，又重第一块参数开始写，这样就能实现平衡写的目的，所以要实现这个功能，至少需要分配2个扇区实现均衡擦写。
/* 储存扇区信息的结构体 */
struct SSCT_HDR
{uint32_t st; // 状态uint32_t cnt; // 标号uint32_t version; // 版本
}; // 扇区HEAD结构typedef struct
{uint16_t len:16; uint16_t alen:16; /* data */
}VARLEN;
struct VAR_ST //Flash数据存储结构
{uint32_t status; //数据当前状态uint32_t key; //数据keyunion {uint32_t len; //数据长度 len +alen 数据实际长度+所在内存长度 内存长度必须是4的整数倍VARLEN len_b;/* data */};};| 扇区1 |
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二、源码
#include <stdbool.h>
#include <stdint.h> //引用框架配置文件#define MAX_CVAR_NUM (200) //数据存储最大个数typedef struct
{uint16_t len:16; uint16_t alen:16; /* data */
}VARLEN;
struct VAR_ST //Flash数据存储结构
{uint32_t status; //数据当前状态uint32_t key; //数据keyunion {uint32_t len; //数据长度 len +alen 数据实际长度+所在内存长度 内存长度必须是4的整数倍VARLEN len_b;/* data */};};struct SFVAR_POINT
{uint32_t key; //数据keyuint8_t* flashAddr; //数据地址
};typedef struct
{uint8_t* sectorBaseAdr;uint32_t sectorSize;uint8_t sectorNum;void (*FlashInit_Cbk)(void); // Flash初始化函数bool (*FlashErase_Cbk)(uint8_t* addr, uint32_t size); // Flash擦除函数uint32_t (*FlashWrite_Cbk)(void* addr, const void* buf, uint32_t size); // Flash写入函数uint32_t (*FlashRead_Cbk)(void* addr, void* buf, uint32_t size); /// flash读函数// privatestruct{uint32_t makeTime;uint8_t* sectorUseBaseAdr; // flash 参数存储区基地址uint8_t sectorUseCnt; // Flash 所有的序号uint32_t varNum; // Flash存储数据个数uint32_t tail; // Flash当前地址uint32_t head; // 有效头部位置uint8_t swSctFlag; //扇区切换flaguint8_t* rmAdr; //需要删除的 地址struct VAR_ST pCVar; //单个参数的头部结构struct SFVAR_POINT varList[MAX_CVAR_NUM]; //数据Z指针数组} pri;}FlashPar_Prop;typedef struct
{void (* const Create)(FlashPar_Prop* self); // FlashVarvoid (*Init)(FlashPar_Prop* self,uint32_t makeTime,uint8_t* sectorBaseAdr, // FLASH基地址uint32_t sectorSize, // flash大小uint32_t sectorNum, // flash块的个数void (*FlashInit_Cbk)(void), // flash初始化函数bool (*FlashErase_Cbk)(uint8_t* addr, uint32_t size), // flash擦除函数uint32_t (*FlashWrite_Cbk)(void* addr, const void* buf, uint32_t size), // flash写入函数uint32_t (*FlashRead_Cbk)(void* addr, void* buf, uint32_t size) // flash读函数);// APIuint32_t (*RdPar)(FlashPar_Prop* self, uint32_t key, uint8_t* pRdBuf, uint32_t bufLen); ///数据读取函数MOBJ_BOOL (*WtPar)(FlashPar_Prop* self, uint32_t key, uint8_t* pWtDat, uint32_t datLen); //数据写入函数MOBJ_BOOL (*DelPar)(FlashPar_Prop* self, uint32_t key); //数据删除函数}FlashPar_Func;extern const FlashPar_Func FlashPar;#include "MFlashVar.h"
#include "string.h"
#include "MTime.h"
/* 扇区使用情况 表示各个扇区状态*/#define SSCT_UNUSE (0xFFFFFFFF) // 未使用
#define SSCT_USE (0xBBBBBBBB) // 使用中
#define SSCT_DEL (0x00000000) // 删除状状态/* 某区域保存参数的状态 */#define SCVAR_UNUSE (0xFFFFFFFF) // 未使用#define SCVAR_USE (0xAAAAAAAA) // 使用中#define SCVAR_DEL (0x00000000) // 删除状状态// 表示各个数据状态/* 储存扇区信息的结构体 */
struct SSCT_HDR
{uint32_t st; // 状态uint32_t cnt; // 标号uint32_t version; // 版本}; // 扇区HEAD结构static int32_t FindVarAddr(FlashPar_Prop *self, uint32_t key);
static uint32_t AllocVar(FlashPar_Prop *self, uint32_t len, uint32_t key);
static void DelVar(FlashPar_Prop *self, uint8_t *addr);
static void PrgVar(FlashPar_Prop *self, void *flashAddr, uint32_t key, uint8_t *pWtDat, uint32_t dataLen);
static void LoadSector(FlashPar_Prop *self);
static void LoadFVar(FlashPar_Prop *self);
static void SwitchSct(FlashPar_Prop *self);/*** @brief FlashPar**/
static void FlashPar_Init(FlashPar_Prop *self,uint32_t makeTime,uint8_t *sectorBaseAdr,uint32_t sectorSize,uint32_t sectorNum,void (*FlashInit_Cbk)(void),bool (*FlashErase_Cbk)(uint8_t *addr, uint32_t size),uint32_t (*FlashWrite_Cbk)(void *addr, const void *buf, uint32_t size),uint32_t (*FlashRead_Cbk)(void *addr, void *buf, uint32_t size) // flash读函数
)
{self->pri.varNum = 0;self->sectorBaseAdr = sectorBaseAdr;self->sectorSize = sectorSize;self->sectorNum = sectorNum;self->pri.makeTime = makeTime;self->FlashInit_Cbk = FlashInit_Cbk;self->FlashErase_Cbk = FlashErase_Cbk;self->FlashWrite_Cbk = FlashWrite_Cbk;self->FlashRead_Cbk = FlashRead_Cbk;// step1: load useing sectorLoadSector(self);// step2 : load flash variableLoadFVar(self);}/*** @brief 申请地址并检查剩余地址是否足够**/
static uint32_t AllocVar(FlashPar_Prop *self, uint32_t len, uint32_t key)
{uint32_t pFVarAddress;uint8_t tmp, actLen;uint16_t index;/******step1 :Caculate the actual space***/tmp = len % 4;if (tmp != 0)actLen = sizeof(struct VAR_ST) + len + (4 - tmp);elseactLen = sizeof(struct VAR_ST) + len;/*step2: check current sector has enough sapace*/if (self->pri.tail + actLen >= self->sectorSize){SwitchSct(self);index = FindVarAddr(self, key);self->pri.rmAdr = self->pri.varList[index].flashAddr;}else {}/*step3: current sector has enough sapace*/if (self->pri.tail + actLen < self->sectorSize){pFVarAddress = (uint32_t)(self->pri.sectorUseBaseAdr + self->pri.tail);self->pri.tail += actLen;}else{pFVarAddress = 0;}return pFVarAddress;
}
/*** @brief 删除原有变量函数**/
static void DelVar(FlashPar_Prop *self, uint8_t *addr)
{uint32_t st;st = SCVAR_DEL;self->FlashWrite_Cbk(addr, &st, sizeof(st));
}
/*** @brief 写入参数**/
static void PrgVar(FlashPar_Prop *self, void *flashAddr, uint32_t key, uint8_t *pWtDat, uint32_t dataLen)
{struct VAR_ST tmpVar;uint32_t tmp;uint32_t dtActLen;uint8_t *pHead = (uint8_t *)flashAddr;uint8_t *pData = (uint8_t *)flashAddr + sizeof(struct VAR_ST);tmp = dataLen % 4;if (tmp != 0)dtActLen = dataLen + (4 - tmp);elsedtActLen = dataLen;tmpVar.status = SCVAR_USE;tmpVar.key = key;tmpVar.len_b.len = dataLen;tmpVar.len_b.alen = dtActLen;self->FlashWrite_Cbk(pHead, (uint8_t *)&tmpVar, sizeof(struct VAR_ST));self->FlashWrite_Cbk(pData, pWtDat, dtActLen);}/*** @brief 根据关键字查询变量**/
static uint32_t FlashPar_RdPar(FlashPar_Prop *self, uint32_t key, uint8_t *pRdBuf, uint32_t bufLen)
{struct VAR_ST pFVar;uint32_t ret = 0;uint8_t *pData;uint32_t len;int32_t index;// find var in ramindex = FindVarAddr(self, key);if (index < 0){return ret;}self->FlashRead_Cbk(self->pri.varList[index].flashAddr, &pFVar, sizeof(struct VAR_ST));len = pFVar.len_b.len;if (bufLen < len){len = bufLen;}pData = self->pri.varList[index].flashAddr + sizeof(struct VAR_ST);self->FlashRead_Cbk(pData, pRdBuf, len);ret = len;return ret;
}
/* 根据KEY 删除一个参数 */
static MOBJ_BOOL FlashPar_DelPar(FlashPar_Prop *self, uint32_t key)
{uint8_t *pFVar;int32_t index;uint32_t MvDataNum;// find var in ramindex = FindVarAddr(self, key);if (index < 0){return NOT;}pFVar = self->pri.varList[index].flashAddr;MvDataNum = self->pri.varNum - (index + 1);while (MvDataNum--){self->pri.varList[index].flashAddr = self->pri.varList[index + 1].flashAddr;self->pri.varList[index].key = self->pri.varList[index + 1].key;index++;}self->pri.varList[index].flashAddr = 0;self->pri.varList[index].key = 0;self->pri.varNum--;DelVar(self, pFVar);return YES;
}/*** @brief 根据key保存一个参数**/
static MOBJ_BOOL FlashPar_WtPar(FlashPar_Prop *self, uint32_t key, uint8_t *pWtDat, uint32_t datLen)
{uint8_t *pNewVar;uint8_t tempdata[258] = {0};struct VAR_ST pOldVar;int32_t index;MOBJ_BOOL ret;if (datLen > 256){}/******step1 :find old var ***/index = FindVarAddr(self, key);/******step2 :wite new var*/if (index < 0) // step2.1 old var not exist{if (self->pri.varNum >= MAX_CVAR_NUM) // check number{ret = NOT;}else if (0 == (pNewVar = (uint8_t *)AllocVar(self, datLen, key))) // alloc space{ret = NOT;}else{PrgVar(self, pNewVar, key, pWtDat, datLen);self->pri.varList[self->pri.varNum].key = key;self->pri.varList[self->pri.varNum].flashAddr = pNewVar;self->pri.varNum++;ret = YES;}}else // step2.2 old var exist{self->pri.rmAdr = self->pri.varList[index].flashAddr;self->FlashRead_Cbk(self->pri.rmAdr, &pOldVar, sizeof(struct VAR_ST));if (pOldVar.key == key){self->FlashRead_Cbk(self->pri.rmAdr + sizeof(struct VAR_ST), tempdata, pOldVar.len_b.len);if ((pOldVar.len_b.len== datLen) && (0 == memcmp(tempdata, pWtDat, datLen))){ret = YES;}else{pNewVar = (uint8_t *)AllocVar(self, datLen, key);if (0 == pNewVar) // alloc space{// EINT;ret = NOT;}else{PrgVar(self, pNewVar, key, pWtDat, datLen); // write new varDelVar(self, self->pri.rmAdr); // 完全删除ret = YES;}self->pri.varList[index].flashAddr = pNewVar;}}}return ret;
}
static int32_t FindVarAddr(FlashPar_Prop *self, uint32_t key)
{int32_t i;for (i = 0; i < self->pri.varNum; i++){if (self->pri.varList[i].key == key)return i;}return -1;
}/*** @brief 加载各个扇区的状态信息**/static void LoadSector(FlashPar_Prop *self)
{int32_t i;int32_t maxSctCnt = 0;uint8_t *useadd = 0;struct SSCT_HDR pSctHdr, newSctHdr;// step1 : find using sectorfor (i = 0; i < self->sectorNum; i++){useadd = self->sectorBaseAdr + i * self->sectorSize;self->FlashRead_Cbk(useadd, &pSctHdr, sizeof(struct SSCT_HDR));// check the version,if ((pSctHdr.version != 0xFFFFFFFF) && (pSctHdr.version != self->pri.makeTime)){self->FlashErase_Cbk(useadd, self->sectorSize);}else{switch (pSctHdr.st){case SSCT_UNUSE: {break;}case SSCT_USE: {if (pSctHdr.cnt >= maxSctCnt){self->pri.sectorUseBaseAdr = useadd;self->pri.sectorUseCnt = i;maxSctCnt = pSctHdr.cnt;}break;}case SSCT_DEL: {break;}}}}// step2 : if don't find using sector them set sector0 is usedif (maxSctCnt == 0){self->pri.sectorUseBaseAdr = self->sectorBaseAdr;self->pri.sectorUseCnt = 0;self->FlashErase_Cbk(self->pri.sectorUseBaseAdr, self->sectorSize); // 擦除 实际地址需newSctHdr.st = SSCT_USE;newSctHdr.cnt = 1;newSctHdr.version = self->pri.makeTime;self->FlashWrite_Cbk(self->pri.sectorUseBaseAdr, (uint8_t *)&newSctHdr, sizeof(struct SSCT_HDR));}self->pri.tail = sizeof(struct SSCT_HDR);
}
/*** @brief 加载flash 区的参数信息**/
static void LoadFVar(FlashPar_Prop *self)
{uint8_t rFlag = 1;struct VAR_ST *pErrVar = 0;struct VAR_ST nowVar;uint32_t errNo = 0;uint8_t *pFVarAddress = 0;// uint8_t* pFVarAddress = 0;while ((self->pri.tail < self->sectorSize) && rFlag){pFVarAddress = self->pri.sectorUseBaseAdr + self->pri.tail;self->FlashRead_Cbk(pFVarAddress, &nowVar, sizeof(struct VAR_ST));switch (nowVar.status){// if the data was unused than over build processcase SCVAR_UNUSE: {rFlag = 0; // stop researchbreak;}case SCVAR_USE: {if ((pErrVar != 0) && (nowVar.key == pErrVar->key)){self->pri.tail += sizeof(struct VAR_ST) + nowVar.len_b.alen;DelVar(self, self->pri.varList[errNo].flashAddr); // 删除原有错误数据self->pri.varList[errNo].flashAddr = pFVarAddress;}else // nomal{self->pri.tail += sizeof(struct VAR_ST) + nowVar.len_b.alen;self->pri.varList[self->pri.varNum].key = nowVar.key;self->pri.varList[self->pri.varNum].flashAddr = pFVarAddress;self->pri.varNum++;}break;}// if deleted than jumpcase SCVAR_DEL: {self->pri.tail += sizeof(struct VAR_ST) + nowVar.len_b.alen;}default: // 参数报错{// self->pri.tail += sizeof(struct VAR_ST) + dtActLen;}}} // end while
}/*** @brief Flash扇区切换 (暂时未确认是否ok)**/
static void SwitchSct(FlashPar_Prop *self)
{uint8_t data[256];struct VAR_ST pOldVar;struct SSCT_HDR pOldSctHD;uint8_t *oldSct = self->pri.sectorUseBaseAdr;self->FlashRead_Cbk(oldSct, &pOldSctHD, sizeof(struct SSCT_HDR));/********step1: find next sector******/self->pri.sectorUseCnt++;if (self->pri.sectorUseCnt >= self->sectorNum){self->pri.sectorUseCnt = 0;}uint8_t *newSct = self->sectorBaseAdr + self->pri.sectorUseCnt * self->sectorSize;self->FlashErase_Cbk(newSct, self->sectorSize); // 擦除即将切换到的扇区 擦除地址开始后的1个扇区/********step2 : produce sector header*******/struct SSCT_HDR newSctHD = {.st = SSCT_USE,.cnt = pOldSctHD.cnt + 1,.version = self->pri.makeTime,};self->pri.sectorUseBaseAdr = (uint8_t *)newSct;self->pri.tail = sizeof(struct SSCT_HDR);// sector write preself->FlashWrite_Cbk(newSct, (uint8_t *)&newSctHD, sizeof(struct SSCT_HDR));/********step3 :将原有参数移动到新区*************/int32_t i;uint8_t *newvaraddr;for (i = 0; i < self->pri.varNum; i++){self->FlashRead_Cbk(self->pri.varList[i].flashAddr, &pOldVar, sizeof(struct VAR_ST));newvaraddr = (uint8_t *)((uint32_t)self->pri.sectorUseBaseAdr + self->pri.tail);self->FlashRead_Cbk(self->pri.varList[i].flashAddr + sizeof(struct VAR_ST), data, pOldVar.len_b.len); // 读数据PrgVar(self, newvaraddr, pOldVar.key, data, pOldVar.len_b.len); // 保存数据self->pri.varList[i].flashAddr = newvaraddr;self->pri.tail += sizeof(struct VAR_ST) + pOldVar.len_b.alen;if (self->pri.tail > self->sectorSize){//扇区溢出return;}}pOldSctHD.st = SSCT_DEL;// sector write preself->FlashWrite_Cbk(oldSct, (uint8_t *)&pOldSctHD, sizeof(struct SSCT_HDR));
}
/*** @brief FlashPar**/
void FlashPar_Create(FlashPar_Prop *self) { memset(self, 0, sizeof(FlashPar_Prop)); }const FlashPar_Func FlashPar = {.Create = FlashPar_Create,.Init = FlashPar_Init,.RdPar = FlashPar_RdPar,.WtPar = FlashPar_WtPar,.DelPar = FlashPar_DelPar};
平衡擦写的流程主要涉及到扇区的选择和切换，以及变量的写入和删除。
1. 首先，在`FlashPar_Init`函数中，通过调用`LoadSector`函数加载扇区的状态信息。该函数会遍历所有扇区，检查状态并选择使用中的扇区作为当前扇区。
2. 接下来，在`LoadFVar`函数中，会加载当前扇区中的flash变量。函数会遍历当前扇区中的每个flash变量，将其存储到`pri.varList`数组中。同时，将当前扇区中的`tail`指针指向下一个可用的地址。
3. 当需要写入一个新的flash变量时，首先通过`AllocVar`函数申请一个地址，并检查当前扇区是否有足够的空间。如果空间不足，则需要切换到下一个扇区，并重新分配地址。然后，通过`PrgVar`函数将变量写入到flash中，并更新`pri.varList`数组和`pri.varNum`变量。如果找到了相同关键字的旧变量，则会先删除旧变量。
4. 当需要删除一个flash变量时，通过`FlashPar_DelPar`函数根据关键字找到变量的地址，并调用`DelVar`函数删除变量。
5. 当需要读取一个flash变量时，通过`FlashPar_RdPar`函数根据关键字找到变量的地址，并将变量的数据读取出来。
在上述流程中，如果当前扇区的空间不足以容纳新的flash变量，就会触发扇区切换。在`SwitchSct`函数中，先找到下一个可用的扇区，并将其标记为使用状态。然后，将当前扇区中的变量逐个移动到新的扇区，并更新变量的地址。同时，将当前扇区的状态设置为删除状态，并将新的扇区的状态设置为使用状态。
通过这样的流程，可以实现对flash的平衡擦写，避免频繁的擦写操作，延长flash的使用寿命。同时，可以方便地存储和读取变量，提供了一种简单有效的持久化存储解决方案。
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