?在嵌入式設備中，很多場景都需要記錄日志，特別是單片機這種存儲資源有限的環境下，就需要一種輕量級的存儲方法。

1、系統日志??

在嵌入式設備應用場景中，系統日志時常可以監控設備軟件的運行狀態，及時記錄問題點以及關鍵信息，方便開發人員后期定位以及解決問題。 本文將講述一種簡易的系統日志記錄方法，用于保存設備的系統日志，視具體嵌入式設備情況而定，可存儲在MCU內部Flash、外部Flash、EEPROM等，本文采用外部Flash作為示例展開介紹。

2、思路分析??

對于系統日志可以當成文件系統，可以劃分為三個重要部分：目錄區、參數區、日志區。

目錄區：根據日期進行歸類，記錄當天的日志的存儲地址、日志索引、日志大小，通過目錄可以獲取整個日志文件的概況；

參數區：存儲記錄日志寫位置、目錄項個數、寫狀態等參數；

日志區：這是我們主要的存儲區，記錄系統的日志，支持環寫。這三個區域都需要占用部分內存，可以自行分配大小。

? 實現的效果如下圖所示，設置通過指令可查詢到整個日志目錄區的概況。 查詢系統日志目錄：AT+CATALOG? LOG_ID:存儲日志按日期分類，該ID用于查詢對應日期日志,從1開始計數； LOG_DATE:系統日志存儲日期； LOG_ADDR:系統日志存儲外部FLASH地址； LOG_OFFSET:系統日志存儲偏移量（各日期日志大小，單位：字節）。
? ?
查詢指定日期系統日志：AT+CATALOG= LOG_ID:在查詢系統日志目錄時獲取，當LOG_ID為0時，為查詢整個系統日志。
?
另外提供移除系統日志（清除日志目錄）指令：AT+RMLOG，后面將講述具體實現。

3、Flash內存劃分?

FLASH內存需要看具體設備進行合理劃分，目錄區、參數區與日志區實現環形存儲，延長擦寫壽命。

#define FLASH_SECTOR_SIZE      ((uint32_t)0x001000)
#define FLASH_BLOCK_32K_SIZE    ((uint32_t)0x008000)
#define FLASH_BLOCK_64K_SIZE    ((uint32_t)0x010000)
#define SECTOR_MASK               (FLASH_SECTOR_SIZE - 1)         /*扇區掩碼 ------*/
#define SECTOR_BASE(addr)         (addr & (~SECTOR_MASK))        /*扇區的基地址 --*/
#define SECTOR_OFFSET(addr)       (addr & SECTOR_MASK)           /*扇區內的偏移 --*/


#define BLOCK_32K_BASE(addr)    (addr & (~(FLASH_BLOCK_32K_SIZE)))
#define BLOCK_64K_BASE(addr)    (addr & (~(FLASH_BLOCK_64K_SIZE)))


typedef enum {
    FLASH_BLOCK_4K  = 0,          /**< flash erase block size 4k */
    FLASH_BLOCK_32K = 1,          /**< flash erase block size 32k */
    FLASH_BLOCK_64K = 2           /**< flash erase block size 64k */
}flash_block_t;


/* flash 空間索引 */
typedef enum{
    FLASH_CATALOG_ZONE = 0,
    FLASH_SYSLOG_PARA_ZONE,
    FLASH_SYSLOG_ZONE,
    FLASH_ZONEX,
}flash_zone_e;


typedef struct{
    flash_zone_e zone;
    uint32_t start_address;
    uint32_t end_address;
}flash_table_t;


/* 地址劃分 */
static const flash_table_t flash_table[] = {
  { .zone = FLASH_CATALOG_ZONE,       .start_address = 0x03200000, .end_address = 0x032FFFFF},  
  { .zone = FLASH_SYSLOG_PARA_ZONE,   .start_address = 0x03300000, .end_address = 0x033FFFFF},  
  { .zone = FLASH_SYSLOG_ZONE,        .start_address = 0x03400000, .end_address = 0x03FFFFFF},  
};

? Flash底層實現擦除、讀寫操作接口，由讀者自行實現。

flash_table_t *get_flash_table(flash_zone_e zone)
{
  int i = 0;
  for (i = 0; i < flash_zone_count; i++) {
    if (zone == flash_table[i].zone) 
      return (flash_table_t *)&flash_table[i];
  }


  return NULL;  
}


int flash_erase(flash_zone_e zone, uint32_t address, flash_block_t block_type)
{
  flash_table_t *flash_table_tmp = get_flash_table(zone);


  if (flash_table_tmp == NULL)
    return -1;


  if (address < flash_table_tmp->start_address ||address > flash_table_tmp->end_address) 
    return -1;


  return bsp_spi_flash_erase(address, block_type);
}


int flash_write(flash_zone_e zone, uint32_t address, const uint8_t*data, uint32_t length)
{
  flash_table_t *flash_table_tmp = get_flash_table(zone);


  if (flash_table_tmp == NULL)
     return -1;


  if ((address < flash_table_tmp->start_address) ||((address + length) > flash_table_tmp->end_address))
     return -1;


  return bsp_spi_flash_buffer_write(address, (uint8_t *)data, length);
}


int flash_read(flash_zone_e zone, uint32_t address, uint8_t*buffer, uint32_t length)
{
  flash_table_t *flash_table_tmp = get_flash_table(zone);


  if (flash_table_tmp == NULL)
    return -1;


  if ((address < flash_table_tmp->start_address) ||((address + length) > flash_table_tmp->end_address))
    return -1;


  bsp_spi_flash_buffer_read(buffer, address, length);
  return 0;
}

? 參數與結構體定義 日志數據存儲時間戳，便于問題定位，需要實現RTC接口調用。

typedef struct {
  uint16_t   Year;    /* 年份:YYYY */
  uint8_t    Month;    /* 月份:MM */
  uint8_t    Day;    /* 日:DD */
  uint8_t     Hour;    /* 小時:HH */
  uint8_t     Minute;    /* 分鐘:MM */
  uint8_t   Second;    /* 秒:SS */
}time_t;   


int?bsp_rtc_get_time(time_t?*date);

? 參數區應當保證數據的正確性，應加入參數校驗存儲，定義校驗結構體。

#define SYSTEM_LOG_MAGIC_PARAM    0x87654321  /* 日志參數標識符 */
typedef struct {
  uint32_t magic;    /* 參數標識符 */
  uint16_t crc;    /* 校驗值 */
  uint16_t len;    /* 參數長度 */
}?single_sav_t;

? 參數區需記錄當前日志記錄的寫位置，以及目錄項個數，還有日志區和目錄區環寫狀態，并且存儲最新時間等等。

/* 日志區參數 */
typedef struct {
  uint32_t   write_pos;             /* 寫位置 */
  uint32_t   catalog_num;            /* 目錄項個數 */
  uint8_t    log_cyclic_status;    /* 系統日志環形寫狀態 */   
  uint8_t    catalog_cyclic_status; /* 日志目錄環形寫狀態 */
  time_t     log_latest_time;     /* 存儲最新時間 */
}system_log_t;


/* 目錄區參數 */
typedef struct {
  uint32_t log_id;     /* 日志索引 */  
  uint32_t log_addr;    /* 日志地址 */
  uint32_t log_offset;  /* 日志偏移大小，單位：字節 */
  time_t   log_time;    /* 日志存儲時間 */
}system_catalog_t;


/* 系統日志參數 */
typedef struct {
  single_sav_t crc_val;
  system_log_t system_log;
  system_catalog_t system_catalog;
}sys_log_param_t;


typedef struct {
  uint8_t system_log_print_enable; /* 系統日志打印使能 */
  uint16_t system_log_print_id;    /* 打印指定id系統日志 */
  uint32_t system_log_param_addr;  /* 當前日志寫地址 */
} sys_ram_t;


sys_ram_t  SysRam;
sys_log_param_t SysLogParam;


sys_ram_t  *gp_sys_ram = &SysRam;
sys_log_param_t?*gp_sys_log?=?&SysLogParam;

?

?

4、實現接口說明

CRC校驗接口，可以自定義實現。

/* 16位CRC校驗高位表 */
static const uint8_t auchCRCHi[]={
0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,
0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,
0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,
0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,
0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,
0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,
0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,
0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,


0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,
0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,
0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,
0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,
0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,
0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,
0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,
0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40
};


/* 16位CRC校驗低位表 */
static const uint8_t auchCRCLo[]={
0x00,0xc0,0xc1,0x01,0xc3,0x03,0x02,0xc2,0xc6,0x06,0x07,0xc7,0x05,0xc5,0xc4,0x04,
0xcc,0x0c,0x0d,0xcd,0x0f,0xcf,0xce,0x0e,0x0a,0xca,0xcb,0x0b,0xc9,0x09,0x08,0xc8,
0xd8,0x18,0x19,0xd9,0x1b,0xdb,0xda,0x1a,0x1e,0xde,0xdf,0x1f,0xdd,0x1d,0x1c,0xdc,
0x14,0xd4,0xd5,0x15,0xd7,0x17,0x16,0xd6,0xd2,0x12,0x13,0xd3,0x11,0xd1,0xd0,0x10,
0xf0,0x30,0x31,0xf1,0x33,0xf3,0xf2,0x32,0x36,0xf6,0xf7,0x37,0xf5,0x35,0x34,0xf4,
0x3c,0xfc,0xfd,0x3d,0xff,0x3f,0x3e,0xfe,0xfa,0x3a,0x3b,0xfb,0x39,0xf9,0xf8,0x38,
0x28,0xe8,0xe9,0x29,0xeb,0x2b,0x2a,0xea,0xee,0x2e,0x2f,0xef,0x2d,0xed,0xec,0x2c,
0xe4,0x24,0x25,0xe5,0x27,0xe7,0xe6,0x26,0x22,0xe2,0xe3,0x23,0xe1,0x21,0x20,0xe0,


0xa0,0x60,0x61,0xa1,0x63,0xa3,0xa2,0x62,0x66,0xa6,0xa7,0x67,0xa5,0x65,0x64,0xa4,
0x6c,0xac,0xad,0x6d,0xaf,0x6f,0x6e,0xae,0xaa,0x6a,0x6b,0xab,0x69,0xa9,0xa8,0x68,
0x78,0xb8,0xb9,0x79,0xbb,0x7b,0x7a,0xba,0xbe,0x7e,0x7f,0xbf,0x7d,0xbd,0xbc,0x7c,
0xb4,0x74,0x75,0xb5,0x77,0xb7,0xb6,0x76,0x72,0xb2,0xb3,0x73,0xb1,0x71,0x70,0xb0,
0x50,0x90,0x91,0x51,0x93,0x53,0x52,0x92,0x96,0x56,0x57,0x97,0x55,0x95,0x94,0x54,
0x9c,0x5c,0x5d,0x9d,0x5f,0x9f,0x9e,0x5e,0x5a,0x9a,0x9b,0x5b,0x99,0x59,0x58,0x98,
0x88,0x48,0x49,0x89,0x4b,0x8b,0x8a,0x4a,0x4e,0x8e,0x8f,0x4f,0x8d,0x4d,0x4c,0x8c,
0x44,0x84,0x85,0x45,0x87,0x47,0x46,0x86,0x82,0x42,0x43,0x83,0x41,0x81,0x80,0x40
};


/* 實現crc功能函數 */
static uint16_t CRC16(uint8_t* puchMsg, uint16_t usDataLen)
{
  uint8_t uchCRCHi=0xff;
  uint8_t uchCRCLo=0xff;
  uint16_t uIndex;


  while(usDataLen--) {
    uIndex=uchCRCHi^*(puchMsg++);
    uchCRCHi=uchCRCLo^auchCRCHi[uIndex];
    uchCRCLo=auchCRCLo[uIndex];
  }


  return uchCRCHi<<8|uchCRCLo;
}

? 保存系統日志參數，每實現寫日志操作后都需要保存當前的參數值，防止意外丟失。

void save_system_log_param(void)
{
  uint32_t i = 0;
  uint32_t addr = 0;
  uint32_t remainbyte = 0;
  uint32_t start_addr;
  int len = sizeof(sys_log_param_t);
  uint8_t *pdata = (uint8_t *)&SysLogParam;
  flash_table_t *flash_tmp = get_flash_table(FLASH_SYSLOG_PARA_ZONE);


  /* 校驗參數 */
  gp_sys_log->crc_val.magic = SYSTEM_LOG_MAGIC_PARAM;
  gp_sys_log->crc_val.len = sizeof(sys_log_param_t) - sizeof(single_sav_t);
  gp_sys_log->crc_val.crc = CRC16(&pdata[sizeof(single_sav_t)], gp_sys_log->crc_val.len);


  start_addr = gp_sys_ram->system_log_param_addr;
  /* 剩余內存不夠寫，則重新從起始地址開始寫，實現環形存儲功能  */
  if ((start_addr + len) > flash_tmp->end_address) { 
    start_addr = flash_tmp->start_address;
  }
  gp_sys_ram->system_log_param_addr = start_addr + len;
  /* 首地址存儲，擦除整個系統日志參數存儲區，如果劃分的內存較大，可能出現第一次擦寫等待時間較長，
     但實際應用嵌入式設備應該不會占用太多的內存存儲系統日志，只當為輔助使用，有額外應用可自行實現 */
  if (flash_tmp->start_address == start_addr) {
    /*for (i = flash_tmp->start_address; i < flash_tmp->end_address; i+= FLASH_SECTOR_SIZE) 
      flash_erase(FLASH_SYSLOG_PARA_ZONE, SECTOR_BASE(i), FLASH_BLOCK_4K);
    */
    addr = flash_tmp->start_address;
    do {
      if ((addr + FLASH_BLOCK_64K_SIZE) <= flash_tmp->end_address) {
        flash_erase(FLASH_SYSLOG_PARA_ZONE, BLOCK_64K_BASE(i), FLASH_BLOCK_64K);
        addr += FLASH_BLOCK_64K_SIZE;
      } else if ((addr + FLASH_BLOCK_32K_SIZE) <= flash_tmp->end_address) {
        flash_erase(FLASH_SYSLOG_PARA_ZONE, BLOCK_32K_BASE(i), FLASH_BLOCK_32K);
        addr += FLASH_BLOCK_32K_SIZE;
      } else if ((addr + FLASH_SECTOR_SIZE) <= flash_tmp->end_address) {
        flash_erase(FLASH_SYSLOG_PARA_ZONE, SECTOR_BASE(i), FLASH_BLOCK_4K);
        addr += FLASH_SECTOR_SIZE;
      } else {
        break;
      }
    } while (addr < flash_tmp->end_address);  
  }


  remainbyte = FLASH_SECTOR_SIZE - (start_addr % FLASH_SECTOR_SIZE);
  if (remainbyte > len) {
    remainbyte = len;
  }
  while (1) {
    flash_write(FLASH_SYSLOG_PARA_ZONE, start_addr, pdata, remainbyte);
    if (remainbyte == len) {
      break;
    } else {
      pdata += remainbyte;
      start_addr += remainbyte;
      len -= remainbyte;
      remainbyte = (len > FLASH_SECTOR_SIZE) ? FLASH_SECTOR_SIZE : len;
    }
  }
}

? 導入系統日志默認參數接口，初始化默認參數或者移除日志。

void load_system_log_default_param(void)
{
  /* 系統日志默認參數 */
  /* 目錄環寫狀態標志 */
  gp_sys_log->system_log.catalog_cyclic_status = 0x00;
  /* 目錄項個數 */
  gp_sys_log->system_log.catalog_num = 0;
  /* 日志環寫標志 , 1:環寫狀態 */
  gp_sys_log->system_log.log_cyclic_status = 0;
  /* 設置默認值，實際會重新從RTC獲取最新時間 */
  gp_sys_log->system_log.log_latest_time.Year = 2019;
  gp_sys_log->system_log.log_latest_time.Month = 5;
  gp_sys_log->system_log.log_latest_time.Day = 8;
  gp_sys_log->system_log.log_latest_time.Hour = 13;
  gp_sys_log->system_log.log_latest_time.Minute = 14;
  gp_sys_log->system_log.log_latest_time.Second = 10;
  /* 日志寫位置從0開始 */
  gp_sys_log->system_log.write_pos = 0;


  gp_sys_log->system_catalog.log_addr = 0;
  gp_sys_log->system_catalog.log_id = 0;
  gp_sys_log->system_catalog.log_offset = 0;
  gp_sys_log->system_catalog.log_time.Year = 2019;
  gp_sys_log->system_catalog.log_time.Month = 5;
  gp_sys_log->system_catalog.log_time.Day = 8;
  gp_sys_log->system_catalog.log_time.Hour = 12;
  gp_sys_log->system_catalog.log_time.Minute = 12;
  gp_sys_log->system_catalog.log_time.Second = 14;


  gp_sys_log->crc_val.magic = SYSTEM_LOG_MAGIC_PARAM;


  /* 導入默認參數后進行保存 */
  save_system_log_param();
}

? 設備開機或者復位都會進行導入系統日志參數操作，恢復日志讀寫參數，參數區為頻繁讀寫操作區域，每一次寫操作都會進行一次偏移，有效的導入參數方法是從參數區結束地址到起始地址進行掃描，掃描不到合法的參數則會導入默認日志參數。

/* 參數初始化，在終端啟動時調用 */
int load_system_log_param(void)
{
  uint32_t i = 0;
  single_sav_t psav;
  uint32_t end_addr;
  uint32_t interal = sizeof(sys_log_param_t);
  int data_len = sizeof(sys_log_param_t) - sizeof(single_sav_t);
  uint8_t *pram = (uint8_t *)&SysLogParam;
  flash_table_t *flash_tmp = get_flash_table(FLASH_SYSLOG_PARA_ZONE);


  end_addr =flash_tmp->end_address - (flash_tmp->end_address - flash_tmp->start_address) % interal;
  for (i = end_addr - interal; i > flash_tmp->start_address; i -= interal) {
    flash_read(FLASH_SYSLOG_PARA_ZONE, i, (uint8_t *)&psav, sizeof(single_sav_t));
    if ((psav.magic == SYSTEM_LOG_MAGIC_PARAM) && (psav.len ==data_len)) {      
      flash_read(FLASH_SYSLOG_PARA_ZONE, i + sizeof(single_sav_t), &pram[sizeof(single_sav_t)], data_len);
      if (psav.crc != CRC16(&pram[sizeof(single_sav_t)], data_len)) 
        continue;
      gp_sys_ram->system_log_param_addr = i;
      log_info("Load System Log Param Addr[0x%08x]!", gp_sys_ram->system_log_param_addr);
      return 0;
    }
  }


  /* 掃描不到合法的參數，導入默認系統日志參數 */
  load_system_log_default_param();
  /* 獲取日志寫地址 */
  gp_sys_ram->system_log_param_addr = flash_tmp->start_address;
  log_info("Load System Log Param Addr(Default)[0x%08x]!", gp_sys_ram->system_log_param_addr);
  return 1;
}

? 讀寫系統日志目錄接口，讀寫指定日志索引目錄信息。實際實現會定義最新的目錄信息存儲在日志參數區，當日期發生改變，則表示當前目錄信息已經完結，將最新的目錄信息錄入日志目錄區保存，最多每天寫入一次目錄區。

/* 讀取日志目錄區指定日志索引目錄信息 */
int system_catalog_read(system_catalog_t *catalog, uint32_t id)
{
  uint32_t addr;
  int rlen = sizeof(system_catalog_t);
  uint8_t *pbuf = (uint8_t *)catalog;
  flash_table_t *flash_tmp = get_flash_table(FLASH_CATALOG_ZONE);


  if (0 == id) 
    return -1;
  addr = flash_tmp->start_address + (rlen * (id - 1));
  if (addr > flash_tmp->end_address) 
    return -1;


  return flash_read(FLASH_CATALOG_ZONE, addr, pbuf, rlen);
}


/* 寫日志目錄區目錄信息 */
int system_catalog_write(system_catalog_t *catalog, uint32_t id)
{
  uint32_t start_offset;
  uint32_t start_addr;
  uint32_t start_base;
  uint32_t remainbyte;
  int wlen = sizeof(system_catalog_t);
  uint8_t *pdata = (uint8_t *)catalog;
  flash_table_t *flash_tmp = get_flash_table(FLASH_CATALOG_ZONE);


  if (0 == id) return -1;
  start_addr = flash_tmp->start_address + wlen * (id - 1);
  if ((start_addr + wlen) > flash_tmp->end_address) {
    start_addr = flash_tmp->start_address;
  }


  /* 本扇區剩余空間大小 */
  remainbyte = FLASH_SECTOR_SIZE - (start_addr % FLASH_SECTOR_SIZE);
  /* 寫入數據長度小于本扇區剩余長度，直接寫入 */
  if (remainbyte > wlen) {
    remainbyte = wlen;
  }
  /* 寫目錄次數不會太頻繁，視具體情況改寫操作實現 */
  while (1) {
    start_base = SECTOR_BASE(start_addr);
      start_offset = SECTOR_OFFSET(start_addr);
    flash_read(FLASH_CATALOG_ZONE, start_base, sector_buf, FLASH_SECTOR_SIZE);
    flash_erase(FLASH_CATALOG_ZONE, start_base, FLASH_BLOCK_4K);
    memcpy((char *)§or_buf[start_offset], pdata, remainbyte);
    flash_write(FLASH_CATALOG_ZONE, start_base, sector_buf, FLASH_SECTOR_SIZE);
    if (remainbyte == wlen) {
      break;
    } else {
      pdata += remainbyte;
      start_addr += remainbyte;
      wlen -= remainbyte;
      remainbyte = (wlen > FLASH_SECTOR_SIZE) ? FLASH_SECTOR_SIZE : wlen;
    }
  }


  return 0;
}

? 打印系統日志目錄區信息，可實現通過指令查詢到目錄區信息。

int system_catalog_all_print(void)
{
  int i = 0;
  system_catalog_t catalog;


  printf("System Log Command Information:
");
  printf("Query Specifies Log : AT+CATALOG=
");
  printf("Query All Log : AT+CATALOG=<0>

");
  printf("Query All System Catalog:
");
  printf("LOG_ID    LOG_DATE    LOG_ADDR    LOG_OFFSET  
");
  for (i = 0; i < gp_sys_log->system_log.catalog_num; i++) {
    /* 當前最新目錄信息 */    
    if (i == (gp_sys_log->system_catalog.log_id - 1)) {
      catalog = gp_sys_log->system_catalog; /* 獲取當前最新目錄信息 */
    } else {
      system_catalog_read(&catalog, i + 1);
    }
    printf("%d    %04d-%02d-%02d    0x%08X    %d  
", 
      catalog.log_id, catalog.log_time.Year, catalog.log_time.Month, catalog.log_time.Day, 
      catalog.log_addr, catalog.log_offset);
    memset((char *)&catalog, 0, sizeof(system_catalog_t));
  }
  return 0;
}

? 讀取指定日志目錄索引信息接口，可指定日志索引或者讀取全部日志數據。

int system_log_task(int argc)
{
  int rlen = 0;
  uint32_t offset, start_addr, end_addr;
  system_catalog_t catalog;
  flash_table_t *flash_tmp =get_flash_table(FLASH_SYSLOG_ZONE);


  if (0 == gp_sys_ram->system_log_print_enable) 
    return 1;


  gp_sys_ram->system_log_print_enable = 0x00;
  if (gp_sys_ram->system_log_print_id == ALL_LOG_PRINT) {
    /* log回環寫標志,打印整個LOG存儲區 */
    if (0x01 == gp_sys_log->system_log.log_cyclic_status) { 
      start_addr = flash_tmp->start_address;
      end_addr = flash_tmp->end_address;
      offset = end_addr - start_addr;
    } else {
      start_addr = flash_tmp->start_address;
      end_addr = start_addr + gp_sys_log->system_log.write_pos;
      offset = gp_sys_log->system_log.write_pos;
    }
  } else { /* 讀取指定ID日志 */
    if (gp_sys_ram->system_log_print_id == gp_sys_log->system_catalog.log_id) {
      catalog = gp_sys_log->system_catalog;
    } else {
      system_catalog_read(&catalog, gp_sys_ram->system_log_print_id);
    }
    start_addr = catalog.log_addr;
    offset = catalog.log_offset;
  }  


  if (0 == offset)
    return 1;


  while (1) {
    rlen = (offset > 512) ? 512 : offset;
    system_log_read(sector_buf, start_addr, rlen);
    HAL_Delay(80);
    /* 目錄信息通過調式串口打印 */
    bsp_debug_send(sector_buf, rlen);
    start_addr += rlen;
    offset -= rlen;
    if (0 == offset) 
      break;
  }
  return 0;
}

? 存儲系統日志接口，實現更新存儲日期，當寫位置為扇區地址，則擦除一個扇區作為存儲日志，這樣避免每寫一次就擦除一次。

int system_log_write(uint8_t *wbuf, int wlen)
{
  uint32_t start_addr;
  uint8_t *pdata = wbuf;
  uint32_t remainbyte;
  int system_catalog_max_id;
  flash_table_t *flash_tmp =get_flash_table(FLASH_SYSLOG_ZONE);


  /* 計算目錄區的最大存儲目錄項個數 */
  system_catalog_max_id = ((flash_tmp->end_address - flash_tmp->start_address) / sizeof(system_catalog_t));
  start_addr = flash_tmp->start_address + gp_sys_log->system_log.write_pos;
  /* 存儲數據地址大于規劃內存地址范圍處理 */
  if ((start_addr + wlen) > flash_tmp->end_address) { 
    start_addr = flash_tmp->start_address;
    /* 寫位置偏移量重置 */
    gp_sys_log->system_log.write_pos = 0;
    /* LOG回環存儲標志置位 */
    gp_sys_log->system_log.log_cyclic_status = 0x01; 
  }
  /* 寫位置偏移 */
  gp_sys_log->system_log.write_pos += wlen; 


  if ((gp_sys_log->system_log.log_latest_time.Year != gp_sys_log->system_catalog.log_time.Year) ||
    (gp_sys_log->system_log.log_latest_time.Month != gp_sys_log->system_catalog.log_time.Month) ||
    (gp_sys_log->system_log.log_latest_time.Day != gp_sys_log->system_catalog.log_time.Day)) {


    /* 日期改變，記錄目錄信息，當log_id為0，則不寫入 */
    system_catalog_write(&gp_sys_log->system_catalog, gp_sys_log->system_catalog.log_id);
    /* 記錄存儲日期 */
    gp_sys_log->system_catalog.log_time = gp_sys_log->system_log.log_latest_time;


    if ((gp_sys_log->system_catalog.log_id + 1) >= system_catalog_max_id) {
      gp_sys_log->system_log.catalog_num = system_catalog_max_id; /* 目錄循環寫，目錄數應為最大 */
      gp_sys_log->system_log.catalog_cyclic_status = 1; /* 目錄回環寫標志 */
    } else {
      if (0 == gp_sys_log->system_log.catalog_cyclic_status) {
        /* 獲取目錄數 */
        gp_sys_log->system_log.catalog_num = gp_sys_log->system_catalog.log_id + 1; 
      }
    }


    /* 存儲最新目錄項信息 */
    gp_sys_log->system_catalog.log_id = (gp_sys_log->system_catalog.log_id + 1) % system_catalog_max_id;
    gp_sys_log->system_catalog.log_addr = start_addr;
    gp_sys_log->system_catalog.log_offset = wlen; 
  } else {
    gp_sys_log->system_catalog.log_offset += wlen; 
  }


  /* 寫位置為存儲起始地址并且不為扇區首地址 */
  if ((flash_tmp->start_address == start_addr) && (SECTOR_OFFSET(flash_tmp->start_address))){
    flash_read(FLASH_SYSLOG_ZONE, SECTOR_BASE(start_addr), sector_buf, FLASH_SECTOR_SIZE);
    flash_erase(FLASH_SYSLOG_ZONE, SECTOR_BASE(start_addr), FLASH_BLOCK_4K);
    /* 將扇區頭部至起始地址區間的數據回寫 */
    flash_write(FLASH_SYSLOG_ZONE, SECTOR_BASE(start_addr), §or_buf[0], SECTOR_OFFSET(start_addr)); 
  }
  /* 寫位置為扇區首地址，則擦除一個扇區的存儲區    */
  if (0 == SECTOR_OFFSET(start_addr)) {
    flash_erase(FLASH_SYSLOG_ZONE, SECTOR_BASE(start_addr), FLASH_BLOCK_4K);
  }


  /* 本扇區剩余空間大小 */
  remainbyte = FLASH_SECTOR_SIZE - (start_addr % FLASH_SECTOR_SIZE);
  /* 寫入數據長度小于本扇區剩余長度，直接寫入 */
  if (remainbyte > wlen) {
    remainbyte = wlen;
  }
  while (1) {
    flash_write(FLASH_SYSLOG_ZONE, start_addr, pdata, remainbyte);
    if (remainbyte == wlen) {
      break;
    } else {
      pdata += remainbyte;
      start_addr += remainbyte;
      wlen -= remainbyte;
      remainbyte = (wlen > FLASH_SECTOR_SIZE) ? FLASH_SECTOR_SIZE : wlen;
      /* 扇區首地址則擦除整個扇區，該扇區數據不保存 */
      if (0 == SECTOR_OFFSET(start_addr)) {
        flash_erase(FLASH_SYSLOG_ZONE, SECTOR_BASE(start_addr), FLASH_BLOCK_4K);
      }
    }
  }


  /* 環形存儲參數 */
  save_system_log_param();
  return 0;
}

?

?

5、系統調試對接

為了更好記錄系統日志，將應用調試等級結合一塊，實現記錄錯誤調試信息以及需要保存的關鍵信息。定義的調試等級有：關閉調試等級、錯誤調試等級、警告調試等級、關鍵調試等級、debug調試等級，而LOG_RECORD_LEVEL將主動保存日志并輸出信息，LOG_ERROR_LEVEL會存儲對應的日志信息，但需要根據應用調試等級輸出信息。設置與讀取應用調試等級由讀者自行定義。

#define LOG_CLOSE_LEVEL        0x00 /* 關閉調試信息 */
#define LOG_ERROR_LEVEL        0x01 /* 錯誤調試信息 */
#define LOG_WARN_LEVEL        0x02 /* 警告調試信息 */
#define LOG_INFO_LEVEL        0x03 /* 關鍵調試信息 */
#define LOG_DEBUG_LEVEL        0x04 /* debug調試信息 */
#define LOG_RECORD_LEVEL      0x10 /* 保存日志并輸出信息 */  
#define LOG_PRINT_LEVEL        0xff


#define SET_LOG_LEVEL(LEVEL)    (gp_sys_param->system_print_level = LEVEL)
#define GET_LOG_LEVEL()        (gp_sys_param->system_print_level)


#define log_debug(fmt, args...)    log_format(LOG_DEBUG_LEVEL, fmt, ##args)
#define log_info(fmt, args...)    log_format(LOG_INFO_LEVEL, fmt, ##args)
#define log_warn(fmt, args...)    log_format(LOG_WARN_LEVEL, fmt, ##args)
#define log_error(fmt, args...)    log_format(LOG_ERROR_LEVEL, fmt, ##args)
#define log_record(fmt, args...)  log_format(LOG_RECORD_LEVEL, fmt, ##args)
#define printf(fmt, args...)    log_format(LOG_PRINT_LEVEL, fmt, ##args)


typedef struct {
  int level;
  char *fmt_str;
}system_print_fmt_t;


system_print_fmt_t system_print_fmt_list[] = {
  { .level = LOG_ERROR_LEVEL,   .fmt_str = ":"},
  { .level = LOG_WARN_LEVEL,    .fmt_str = ":"},
  { .level = LOG_INFO_LEVEL,    .fmt_str = ":"},
  { .level = LOG_DEBUG_LEVEL,   .fmt_str = ":"},
  { .level = LOG_RECORD_LEVEL,  .fmt_str = ":"},
};


int log_format(uint8_t level, const char *fmt, ...)
{
  #define TIME_PREFIX_SIZE  (21)
  #define PRINT_MAX_SIZE    (1024 + TIME_PREFIX_SIZE)


    va_list args;
    int num = 0, i = 0, fmt_index = 0;
    int fmt_str_len = 0, ret = -1;
    int file_str_len = 0, line_str_len = 0;
    char line_buf[20] = {0};
    static char buf[PRINT_MAX_SIZE];
  static QueueHandle_t sem = NULL;
  time_t time = {0};


  /* 針對os系統 */
  if (NULL == sem) {
        sem = xSemaphoreCreateCounting(1, 1); /* always think of success */
  }


  xSemaphoreTake(sem, portMAX_DELAY);


  ret = -1;
  fmt_str_len = 0;
  if (level != LOG_PRINT_LEVEL) {
    if ((GET_LOG_LEVEL() < level) && (level != LOG_RECORD_LEVEL) && (level != LOG_ERROR_LEVEL))
      goto exit_end;


    for (i = 0; i < SYSTEM_PRINT_FMT_LIST_MAX; i++) {
      if (level == system_print_fmt_list[i].level) {
        fmt_index = i;
        break;
      }
    }
    if (i > SYSTEM_PRINT_FMT_LIST_MAX) {
      goto exit_end;
    }


    fmt_str_len = strlen(system_print_fmt_list[fmt_index].fmt_str);
    strncpy((char *)&buf[TIME_PREFIX_SIZE], system_print_fmt_list[fmt_index].fmt_str, fmt_str_len);
  }


    va_start(args, fmt);
    num = vsnprintf((char *)&buf[fmt_str_len + TIME_PREFIX_SIZE], PRINT_MAX_SIZE - fmt_str_len - TIME_PREFIX_SIZE - 2, fmt, args);
    va_end(args);


    if (num <= 0) {
    goto exit_end;
    }


  if (level != LOG_PRINT_LEVEL) {
    num += fmt_str_len;
    buf[num + TIME_PREFIX_SIZE] = '
';
    buf[num + TIME_PREFIX_SIZE + 1] = '
';
    num += 2;
  }


  if ((GET_LOG_LEVEL() < level) && (level == LOG_ERROR_LEVEL)) {
    //do nothing
  } else {
    ret = bsp_debug_send((uint8_t*)&buf[TIME_PREFIX_SIZE], num);  
  }


  if ((LOG_ERROR_LEVEL == level) || (LOG_RECORD_LEVEL == level)) {
    bsp_rtc_get_time(&time);
    sprintf(&buf[0], "[%04d-%02d-%02d %02d:%02d:%02d",
      time.Year, time.Month, time.Day,time.Hour, time.Minute, time.Second);
    buf[TIME_PREFIX_SIZE - 1] = ']';
    gp_sys_log->system_log.log_latest_time = time;
    system_log_write((uint8_t *)buf, num + TIME_PREFIX_SIZE);
  }  


exit_end:
  xSemaphoreGive(sem);
  return ret;
}

?

?

6、結語

本文提供的一種簡易嵌入式設備系統日志記錄方法，代碼量不多，實現簡單，針對不同的設備需要合理規劃內存使用。 ? 根據軟件運行狀態，合適加入調試信息并保存對應的日志信息，方便開發人員了解系統或軟件運行狀況，協助開發分析數據資源從而更好完善系統，提高定位以及解決問題的效果。 ?

　審核編輯：湯梓紅