嵌入式设备系统日志记录方法

在嵌入式设备应用场景中，系统日志时常可以监控设备软件的运行状态，及时记录问题点以及关键信息，方便开发人员后期定位以及解决问题。本文将讲述一种简易的系统日志记录方法，用于保存设备的系统日志，视具体嵌入式设备情况而定，可存储在MCU内部Flash、外部Flash、EEPROM等，本文采用外部Flash作为示例展开介绍。

思路分析 对于系统日志可以当成文件系统，可以划分为三个重要部分：目录区、参数区、日志区。目录区：根据日期进行归类，记录当天的日志的存储地址、日志索引、日志大小，通过目录可以获取整个日志文件的概况；参数区：存储记录日志写位置、目录项个数、写状态等参数；日志区：这是我们主要的存储区，记录系统的日志，支持环写。这三个区域都需要占用部分内存，可以自行分配大小。

实现的效果如下图所示，设置通过指令可查询到整个日志目录区的概况。

查询系统日志目录：AT+CATALOG? LOG_ID: 存储日志按日期分类，该ID用于查询对应日期日志,从1开始计数； LOG_DATE: 系统日志存储日期； LOG_ADDR: 系统日志存储外部FLASH地址； LOG_OFFSET: 系统日志存储偏移量（各日期日志大小，单位：字节）。

查询指定日期系统日志：AT+CATALOG=

LOG_ID:在查询系统日志目录时获取，当LOG_ID为0时，为查询整个系统日志。

另外提供移除系统日志（清除日志目录）指令：AT+RMLOG，后面将讲述具体实现。

FLASH内存划分 FLASH内存需要看具体设备进行合理划分，目录区、参数区与日志区实现环形存储，延长擦写寿命。

#defineFLASH_SECTOR_SIZE((uint32_t)0x001000)
#defineFLASH_BLOCK_32K_SIZE((uint32_t)0x008000)
#defineFLASH_BLOCK_64K_SIZE((uint32_t)0x010000)
#defineSECTOR_MASK(FLASH_SECTOR_SIZE-1)/*扇区掩码------*/
#defineSECTOR_BASE(addr)(addr&(~SECTOR_MASK))/*扇区的基地址--*/
#defineSECTOR_OFFSET(addr)(addr&SECTOR_MASK)/*扇区内的偏移--*/

#defineBLOCK_32K_BASE(addr)(addr&(~(FLASH_BLOCK_32K_SIZE)))
#defineBLOCK_64K_BASE(addr)(addr&(~(FLASH_BLOCK_64K_SIZE)))

typedefenum{
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 空间索引 */
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;

/* 地址划分 */
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底层实现擦除、读写操作接口，由读者自行实现。

flash_table_t*get_flash_table(flash_zone_ezone)
{
inti=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;

returnbsp_spi_flash_erase(address,block_type);
}

intflash_write(flash_zone_ezone,uint32_taddress,constuint8_t*data,uint32_tlength)
{
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;

returnbsp_spi_flash_buffer_write(address,(uint8_t*)data,length);
}

intflash_read(flash_zone_ezone,uint32_taddress,uint8_t*buffer,uint32_tlength)
{
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);
return0;
}

参数与结构体定义 日志数据存储时间戳，便于问题定位，需要实现RTC接口调用。

typedefstruct{
uint16_tYear;/*年份:YYYY*/
uint8_tMonth;/*月份:MM*/
uint8_tDay;/*日:DD*/
uint8_tHour;/*小时:HH*/
uint8_tMinute;/*分钟:MM*/
uint8_tSecond;/*秒:SS*/
}time_t;

intbsp_rtc_get_time(time_t*date);

参数区应当保证数据的正确性，应加入参数校验存储，定义校验结构体。

#defineSYSTEM_LOG_MAGIC_PARAM0x87654321/*日志参数标识符*/
typedefstruct{
uint32_tmagic;/*参数标识符*/
uint16_tcrc;/*校验值*/
uint16_tlen;/*参数长度*/
}single_sav_t;

参数区需记录当前日志记录的写位置，以及目录项个数，还有日志区和目录区环写状态，并且存储最新时间等等。

/*日志区参数*/
typedefstruct{
uint32_twrite_pos;/*写位置*/
uint32_tcatalog_num;/*目录项个数*/
uint8_tlog_cyclic_status;/*系统日志环形写状态*/
uint8_tcatalog_cyclic_status;/*日志目录环形写状态*/
time_tlog_latest_time;/*存储最新时间*/
}system_log_t;

/*目录区参数*/
typedefstruct{
uint32_tlog_id;/*日志索引*/
uint32_tlog_addr;/*日志地址*/
uint32_tlog_offset;/*日志偏移大小，单位：字节*/
time_tlog_time;/*日志存储时间*/
}system_catalog_t;

/*系统日志参数*/
typedefstruct{
single_sav_tcrc_val;
system_log_tsystem_log;
system_catalog_tsystem_catalog;
}sys_log_param_t;

typedefstruct{
uint8_tsystem_log_print_enable;/*系统日志打印使能*/
uint16_tsystem_log_print_id;/*打印指定id系统日志*/
uint32_tsystem_log_param_addr;/*当前日志写地址*/
}sys_ram_t;

sys_ram_tSysRam;
sys_log_param_tSysLogParam;

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

实现接口说明 CRC校验接口，可以自定义实现。

/*16位CRC校验高位表*/
staticconstuint8_tauchCRCHi[]={
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校验低位表*/
staticconstuint8_tauchCRCLo[]={
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
};

/*实现crc功能函数*/
staticuint16_tCRC16(uint8_t*puchMsg,uint16_tusDataLen)
{
uint8_tuchCRCHi=0xff;
uint8_tuchCRCLo=0xff;
uint16_tuIndex;

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

returnuchCRCHi<<8|uchCRCLo;
}

保存系统日志参数，每实现写日志操作后都需要保存当前的参数值，防止意外丢失。

voidsave_system_log_param(void)
{
uint32_ti=0;
uint32_taddr=0;
uint32_tremainbyte=0;
uint32_tstart_addr;
intlen=sizeof(sys_log_param_t);
uint8_t*pdata=(uint8_t*)&SysLogParam;
flash_table_t*flash_tmp=get_flash_table(FLASH_SYSLOG_PARA_ZONE);

/*校验参数*/
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;
/*剩余内存不够写，则重新从起始地址开始写，实现环形存储功能*/
if((start_addr+len)>flash_tmp->end_address){
start_addr=flash_tmp->start_address;
}
gp_sys_ram->system_log_param_addr=start_addr+len;
/*首地址存储，擦除整个系统日志参数存储区，如果划分的内存较大，可能出现第一次擦写等待时间较长，
但实际应用嵌入式设备应该不会占用太多的内存存储系统日志，只当为辅助使用，有额外应用可自行实现*/
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;
}elseif((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;
}elseif((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;
}
}
}

导入系统日志默认参数接口，初始化默认参数或者移除日志。

voidload_system_log_default_param(void)
{
/*系统日志默认参数*/
/*目录环写状态标志*/
gp_sys_log->system_log.catalog_cyclic_status=0x00;
/*目录项个数*/
gp_sys_log->system_log.catalog_num=0;
/*日志环写标志,1:环写状态*/
gp_sys_log->system_log.log_cyclic_status=0;
/*设置默认值，实际会重新从RTC获取最新时间*/
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;
/*日志写位置从0开始*/
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;

/*导入默认参数后进行保存*/
save_system_log_param();
}

设备开机或者复位都会进行导入系统日志参数操作，恢复日志读写参数，参数区为频繁读写操作区域，每一次写操作都会进行一次偏移，有效的导入参数方法是从参数区结束地址到起始地址进行扫描，扫描不到合法的参数则会导入默认日志参数。

/*参数初始化，在终端启动时调用*/
intload_system_log_param(void)
{
uint32_ti=0;
single_sav_tpsav;
uint32_tend_addr;
uint32_tinteral=sizeof(sys_log_param_t);
intdata_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("LoadSystemLogParamAddr[0x%08x]!",gp_sys_ram->system_log_param_addr);
return0;
}
}

/*扫描不到合法的参数，导入默认系统日志参数*/
load_system_log_default_param();
/*获取日志写地址*/
gp_sys_ram->system_log_param_addr=flash_tmp->start_address;
log_info("LoadSystemLogParamAddr(Default)[0x%08x]!",gp_sys_ram->system_log_param_addr);
return1;
}

读写系统日志目录接口，读写指定日志索引目录信息。实际实现会定义最新的目录信息存储在日志参数区，当日期发生改变，则表示当前目录信息已经完结，将最新的目录信息录入日志目录区保存，最多每天写入一次目录区。

/*读取日志目录区指定日志索引目录信息*/
intsystem_catalog_read(system_catalog_t*catalog,uint32_tid)
{
uint32_taddr;
intrlen=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;

returnflash_read(FLASH_CATALOG_ZONE,addr,pbuf,rlen);
}

/*写日志目录区目录信息*/
intsystem_catalog_write(system_catalog_t*catalog,uint32_tid)
{
uint32_tstart_offset;
uint32_tstart_addr;
uint32_tstart_base;
uint32_tremainbyte;
intwlen=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;
}

/*本扇区剩余空间大小*/
remainbyte=FLASH_SECTOR_SIZE-(start_addr%FLASH_SECTOR_SIZE);
/*写入数据长度小于本扇区剩余长度，直接写入*/
if(remainbyte>wlen){
remainbyte=wlen;
}
/*写目录次数不会太频繁，视具体情况改写操作实现*/
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;
}
}

return0;
}

打印系统日志目录区信息，可实现通过指令查询到目录区信息。

intsystem_catalog_all_print(void)
{
inti=0;
system_catalog_tcatalog;

printf("SystemLogCommandInformation:
");
printf("QuerySpecifiesLog:AT+CATALOG=
");
printf("QueryAllLog:AT+CATALOG=<0>

");
printf("QueryAllSystemCatalog:
");
printf("LOG_IDLOG_DATELOG_ADDRLOG_OFFSET
");
for(i=0;i< gp_sys_log->system_log.catalog_num;i++){
/*当前最新目录信息*/
if(i==(gp_sys_log->system_catalog.log_id-1)){
catalog=gp_sys_log->system_catalog;/*获取当前最新目录信息*/
}else{
system_catalog_read(&catalog,i+1);
}
printf("%d%04d-%02d-%02d0x%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));
}
return0;
}

读取指定日志目录索引信息接口，可指定日志索引或者读取全部日志数据。

intsystem_log_task(intargc)
{
intrlen=0;
uint32_toffset,start_addr,end_addr;
system_catalog_tcatalog;
flash_table_t*flash_tmp=get_flash_table(FLASH_SYSLOG_ZONE);

if(0==gp_sys_ram->system_log_print_enable)
return1;

gp_sys_ram->system_log_print_enable=0x00;
if(gp_sys_ram->system_log_print_id==ALL_LOG_PRINT){
/*log回环写标志,打印整个LOG存储区*/
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{/*读取指定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)
return1;

while(1){
rlen=(offset>512)?512:offset;
system_log_read(sector_buf,start_addr,rlen);
HAL_Delay(80);
/*目录信息通过调式串口打印*/
bsp_debug_send(sector_buf,rlen);
start_addr+=rlen;
offset-=rlen;
if(0==offset)
break;
}
return0;
}

存储系统日志接口，实现更新存储日期，当写位置为扇区地址，则擦除一个扇区作为存储日志，这样避免每写一次就擦除一次。

intsystem_log_write(uint8_t*wbuf,intwlen)
{
uint32_tstart_addr;
uint8_t*pdata=wbuf;
uint32_tremainbyte;
intsystem_catalog_max_id;
flash_table_t*flash_tmp=get_flash_table(FLASH_SYSLOG_ZONE);

/*计算目录区的最大存储目录项个数*/
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;
/*存储数据地址大于规划内存地址范围处理*/
if((start_addr+wlen)>flash_tmp->end_address){
start_addr=flash_tmp->start_address;
/*写位置偏移量重置*/
gp_sys_log->system_log.write_pos=0;
/*LOG回环存储标志置位*/
gp_sys_log->system_log.log_cyclic_status=0x01;
}
/*写位置偏移*/
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)){

/*日期改变，记录目录信息，当log_id为0，则不写入*/
system_catalog_write(&gp_sys_log->system_catalog,gp_sys_log->system_catalog.log_id);
/*记录存储日期*/
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;/*目录循环写，目录数应为最大*/
gp_sys_log->system_log.catalog_cyclic_status=1;/*目录回环写标志*/
}else{
if(0==gp_sys_log->system_log.catalog_cyclic_status){
/*获取目录数*/
gp_sys_log->system_log.catalog_num=gp_sys_log->system_catalog.log_id+1;
}
}

/*存储最新目录项信息*/
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;
}

/*写位置为存储起始地址并且不为扇区首地址*/
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);
/*将扇区头部至起始地址区间的数据回写*/
flash_write(FLASH_SYSLOG_ZONE,SECTOR_BASE(start_addr),§or_buf[0],SECTOR_OFFSET(start_addr));
}
/*写位置为扇区首地址，则擦除一个扇区的存储区*/
if(0==SECTOR_OFFSET(start_addr)){
flash_erase(FLASH_SYSLOG_ZONE,SECTOR_BASE(start_addr),FLASH_BLOCK_4K);
}

/*本扇区剩余空间大小*/
remainbyte=FLASH_SECTOR_SIZE-(start_addr%FLASH_SECTOR_SIZE);
/*写入数据长度小于本扇区剩余长度，直接写入*/
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;
/*扇区首地址则擦除整个扇区，该扇区数据不保存*/
if(0==SECTOR_OFFSET(start_addr)){
flash_erase(FLASH_SYSLOG_ZONE,SECTOR_BASE(start_addr),FLASH_BLOCK_4K);
}
}
}

/*环形存储参数*/
save_system_log_param();
return0;
}

系统调试对接 为了更好记录系统日志，将应用调试等级结合一块，实现记录错误调试信息以及需要保存的关键信息。定义的调试等级有：关闭调试等级、错误调试等级、警告调试等级、关键调试等级、debug调试等级，而LOG_RECORD_LEVEL将主动保存日志并输出信息，LOG_ERROR_LEVEL会存储对应的日志信息，但需要根据应用调试等级输出信息。设置与读取应用调试等级由读者自行定义。

#defineLOG_CLOSE_LEVEL0x00/*关闭调试信息*/
#defineLOG_ERROR_LEVEL0x01/*错误调试信息*/
#defineLOG_WARN_LEVEL0x02/*警告调试信息*/
#defineLOG_INFO_LEVEL0x03/*关键调试信息*/
#defineLOG_DEBUG_LEVEL0x04/*debug调试信息*/
#defineLOG_RECORD_LEVEL0x10/*保存日志并输出信息*/
#defineLOG_PRINT_LEVEL0xff

#defineSET_LOG_LEVEL(LEVEL)(gp_sys_param->system_print_level=LEVEL)
#defineGET_LOG_LEVEL()(gp_sys_param->system_print_level)

#definelog_debug(fmt,args...)log_format(LOG_DEBUG_LEVEL,fmt,##args)
#definelog_info(fmt,args...)log_format(LOG_INFO_LEVEL,fmt,##args)
#definelog_warn(fmt,args...)log_format(LOG_WARN_LEVEL,fmt,##args)
#definelog_error(fmt,args...)log_format(LOG_ERROR_LEVEL,fmt,##args)
#definelog_record(fmt,args...)log_format(LOG_RECORD_LEVEL,fmt,##args)
#defineprintf(fmt,args...)log_format(LOG_PRINT_LEVEL,fmt,##args)

typedefstruct{
intlevel;
char*fmt_str;
}system_print_fmt_t;

system_print_fmt_tsystem_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=":"},
};

intlog_format(uint8_tlevel,constchar*fmt,...)
{
#defineTIME_PREFIX_SIZE(21)
#definePRINT_MAX_SIZE(1024+TIME_PREFIX_SIZE)

va_listargs;
intnum=0,i=0,fmt_index=0;
intfmt_str_len=0,ret=-1;
intfile_str_len=0,line_str_len=0;
charline_buf[20]={0};
staticcharbuf[PRINT_MAX_SIZE];
staticQueueHandle_tsem=NULL;
time_ttime={0};

/*针对os系统*/
if(NULL==sem){
sem=xSemaphoreCreateCounting(1,1);/*alwaysthinkofsuccess*/
}

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){
gotoexit_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);
returnret;
}

结语 本文提供的一种简易嵌入式设备系统日志记录方法，代码量不多，实现简单，针对不同的设备需要合理规划内存使用，根据软件运行状态，合适加入调试信息并保存对应的日志信息，方便开发人员了解系统或软件运行状况，协助开发分析数据资源从而更好完善系统，提高定位以及解决问题的效果。

审核编辑：汤梓红