STM32用flash保存参数实现平衡擦写的一种方法

#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	扇区使用状态 扇区 标号 扇区版本号 数据状态ad1 数据key 长度 len alen1 D1 D1 D1 D1 D1 D1 数据状态ad1+ alen1/4 数据key 长度 Len2 Alen2 D2 D2 D2 D2 D2 D2 数据状态ad2+ Alen2/4 数据key 长度 Len3 Alen3 D3 D3 D3 D3 D3 D3 D3 D3 D3 D3 D3 D3 ... ... ... ... ... ... ... ... ...

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。