FS4412中uboot對emmc的分區(qu)解析
時間：2017-11-27 ; 來源：未知
Author：runner 2017.10.15
聲明
平臺： fs4412 （Samsung exynos4412）
u-boot版本： u-boot-2010.03-FS4412
簡述
在FS4412的(de)(de)開發(fa)中，uboot通(tong)過movi、fdisk、fastboot等命令對emmc做了相(xiang)應(ying)的(de)(de)分(fen)(fen)區(qu)操作，這里(li)主要(yao)分(fen)(fen)析，這些命令是(shi)如何對emmc進行分(fen)(fen)區(qu)的(de)(de)，每條命令使用的(de)(de)分(fen)(fen)區(qu)之(zhi)間(jian)有什么聯系和區(qu)別。
uboot對emmc分區分析
整個u-boot源碼的(de)入(ru)口是在u-boot-2010.03-FS4412/cpu/arm_cortexa9/start.S，對于該(gai)文(wen)件(jian)中所做(zuo)的(de)具體工作，我們這里進行分析，主要看該(gai)文(wen)件(jian)中調用(yong)emmc初(chu)始化(hua)的(de)位置：
圖中(zhong)提示的start_armboot函(han)(han)數(shu)(shu)的實現是(shi)在(zai)u-boot-2010.03-FS4412/lib_arm/board.c中(zhong)；當然我們的目的肯定不是(shi)只(zhi)簡單(dan)的找到(dao)這(zhe)個(ge)函(han)(han)數(shu)(shu)就(jiu)夠了，我們需要了解這(zhe)個(ge)函(han)(han)數(shu)(shu)中(zhong)還調用了一個(ge)關鍵(jian)的函(han)(han)數(shu)(shu)接口去初始化emmc，如(ru)下：
這(zhe)里(li)的(de)(de)mmc_initialize函(han)(han)數的(de)(de)具(ju)體(ti)實(shi)(shi)現是(shi)在(zai)u-boot-2010.03-FS4412/drivers/mmc/mmc.c中；那么該(gai)函(han)(han)數的(de)(de)主要目(mu)的(de)(de)實(shi)(shi)際上是(shi)調用(yong)(yong)mmc_init，mmc_init又是(shi)如(ru)何(he)實(shi)(shi)現的(de)(de)？我(wo)(wo)們接著往下(xia)追，mmc_init函(han)(han)數的(de)(de)實(shi)(shi)現還是(shi)在(zai)這(zhe)個文件中。我(wo)(wo)們的(de)(de)目(mu)的(de)(de)是(shi)找(zhao)到mmc被分區的(de)(de)部分為大家(jia)解讀，所以對于這(zhe)個函(han)(han)數其(qi)它部分就不做贅(zhui)述，這(zhe)里(li)只看該(gai)函(han)(han)數后(hou)調用(yong)(yong)的(de)(de)mmc_startup,如(ru)下(xia)：
mmc_startup函數的實(shi)現也(ye)是在(zai)上(shang)述文件中，該(gai)函數調用init_raw_area_table接口實(shi)現對emmc的分區操作：
init_raw_area_table函數的實現是(shi)在u-boot-2010.03-FS4412/common/cmd_movi.c中。具體實現如(ru)下：
C++ Code
int init_raw_area_table (block_dev_desc_t *dev_desc)
{
struct mmc *host = find_mmc_device(dev_desc->dev);
/* when last block does not have raw_area definition. */
if (raw_area_control.magic_number != MAGIC_NUMBER_MOVI)
{
int i = 0;
member_t *image;
u32 capacity;
dbg("The host name is %s\n", host->name);
if(host->high_capacity)
{
capacity = host->capacity;
}
else
{
capacity = host->capacity * (host->read_bl_len / MOVI_BLKSIZE);
}
dbg("Warning: cannot find the raw area table(%p) %08x\n",
&raw_area_control, raw_area_control.magic_number);
/* add magic number */
raw_area_control.magic_number = MAGIC_NUMBER_MOVI;
/* init raw_area will be 16MB */
raw_area_control.start_blk = 16 * 1024 * 1024 / MOVI_BLKSIZE;
raw_area_control.total_blk = capacity;
raw_area_control.next_raw_area = 0;
strcpy(raw_area_control.description, "initial raw table");
image = raw_area_control.image;
/* image 0 should be fwbl1 */
if(strcmp(host->name, "S5P_MSHC4") == 0)
; image[0].start_blk = 0;
else
image[0].start_blk = (eFUSE_SIZE / MOVI_BLKSIZE);
image[0].used_blk = MOVI_FWBL1_BLKCNT;
image[0].size = FWBL1_SIZE;
image[0].attribute = 0x0;
strcpy(image[0].description, "fwbl1");
dbg("fwbl1: %d\n", image[0].start_blk);
; /* image 1 should be bl2 */
image[1].start_blk = image[0].start_blk + image[0].used_blk;
image[1].used_blk = MOVI_BL2_BLKCNT;
image[1].size = BL2_SIZE;
image[1].attribute = 0x3;
strcpy(image[1].description, "bl2");
dbg("bl2: %d\n", image[1].start_blk);
#if 0
/* image 2 should be uboot */
image[2].start_blk = image[1].start_blk + image[1].used_blk;
image[2].used_blk = MOVI_UBOOT_BLKCNT;
image[2].size = PART_SIZE_UBOOT;
image[2].attribute = 0x2;
strcpy(image[2].description, "bootloader");
dbg("u-boot: %d\n", image[2].start_blk);
#else
/*BL1,BL2,u-boot have been combined together when compiling for EMMC*/
if(strcmp(host->name, "S5P_MSHC4") == 0)
image[2].start_blk = 0;
else
image[2].start_blk = (eFUSE_SIZE / MOVI_BLKSIZE);
image[2].used_blk = MOVI_FWBL1_BLKCNT + MOVI_UBOOT_BLKCNT + MOVI_BL2_BLKCNT;
image[2].size = PART_SIZE_UBOOT + FWBL1_SIZE + BL2_SIZE;
image[2].attribute = 0x2;
strcpy(image[2].description, "bootloader");
dbg("u-boot: %d\n";, image[2].start_blk);
#endif
/* image 3 should be environment */
; image[3].start_blk = (544 * 1024) / MOVI_BLKSIZE;
image[3].used_blk = MOVI_ENV_BLKCNT;
image[3].size = CONFIG_ENV_SIZE;
image[3].attribute = 0x10;
strcpy(image[3].description, "environment");
dbg("env: %d\n", image[3].start_blk);
/* image 4 should be kernel */
image[4].start_blk = image[3].start_blk + image[3].used_blk;
image[4].used_blk = MOVI_ZIMAGE_BLKCNT;
image[4].size = PART_SIZE_KERNEL;
image[4].attribute = 0x4;
strcpy(image[4].description, "kernel");
dbg("knl: %d\n", image[4].start_blk);
/* image 5 should be RFS */
image[5].start_blk = image[4].start_blk + image[4].used_blk;
; image[5].used_blk = MOVI_ROOTFS_BLKCNT;
image[5].size = PART_SIZE_ROOTFS;
image[5].attribute = 0x8;
strcpy(image[5].description, "ramdisk");
dbg("rfs: %d\n", image[5].start_blk);
#ifdef CONFIG_RECOVERY
/* image 6 should be Recovery */
image[6].start_blk = image[5].start_blk + image[5].used_blk;
image[6].used_blk = RAW_AREA_SIZE / MOVI_BLKSIZE - image[5].start_blk;
image[6].size = image[6].used_blk * MOVI_BLKSIZE;
image[6].attribute = 0x6;
strcpy(image[6].description, "Recovery");
dbg("recovery: %d\n", image[6].start_blk);
#endif
; /* image 7 should be disk */
; image[7].start_blk = RAW_AREA_SIZE / MOVI_BLKSIZE;
image[7].size = capacity - RAW_AREA_SIZE;
image[7].used_blk = image[7].size / MOVI_BLKSIZE;
image[7].attribute = 0xff;
; strcpy(image[7].description, "disk");
; dbg("disk: %d\n", image[7].start_blk);
for (i = 8; i < 15; i++)
{
raw_area_control.image[i].start_blk = 0;
raw_area_control.image[i].used_blk = 0;
}
}
return 0;
}
可以看到：
image[0] 存放的是(shi)BL1，start_blk = 0 / 1,used_blk = (8*1024)/512
image[1] 存放的是BL2，start_blk = image[0].start_blk + image[0].used_blk; used_blk = (16*1024)/512
image[2] 存放的是Bootloader,
image[3] 存放的是(shi)environment（環境變量）
image[4] 存放的是(shi)kernel
image[5] 存放(fang)的是(shi)ramdisk
image[6] 存放的是Recovery
image[7] 存放的是disk（即文件系(xi)統）
后面的(de)(de)幾個分區的(de)(de)起始地址和使用地址，都是通過上面一一偏(pian)移得到的(de)(de)，有興趣(qu)的(de)(de)同學(xue)可以自己查閱源碼進(jin)行計(ji)算。這樣(yang)的(de)(de)話(hua)，我們就知道了(le)平時(shi)燒寫(xie)的(de)(de)kernel鏡像或者ramdisk鏡像在emmc中存放(fang)的(de)(de)地址空間了(le)。
fdisk命令分區分析
我們知道使(shi)用fdisk命(ming)令(ling)對(dui)emmc 分區時，命(ming)令(ling)格式如(ru)下：
fdisk -c 0 300 1024 300
或者使用(yong)fdisk命(ming)令查詢(xun)分區(qu)大小(xiao)：
fdisk -p 0
那么(me)這四個分(fen)區分(fen)別代表什么(me)意思呢？要搞清楚這個問題，我們(men)就要去看(kan)fdisk命令(ling)的(de)(de)實(shi)(shi)現(xian)過(guo)程(cheng)了(le)，fdisk命令(ling)在uboot源碼中實(shi)(shi)現(xian)的(de)(de)位置(zhi)是在common/cmd_mmc_fdisk.c中。在該文件中對(dui)于這個命令(ling)其它實(shi)(shi)現(xian)的(de)(de)部(bu)分(fen)我不做贅述，直接看(kan)具體分(fen)區的(de)(de)操作，函數(shu)名稱為：make_mmc_partition , 實(shi)(shi)現(xian)如下：
C++ Code
int make_mmc_partition(int total_block_count, unsigned char *mbr, int flag, char *argv[])
{
unsigned int block_start = 0, block_offset;
SDInfo sdInfo;
PartitionInfo partInfo[4];
///////////////////////////////////////////////////////////
memset((unsigned char *)&sdInfo, 0x00, sizeof(SDInfo));
///////////////////////////////////////////////////////////
get_SDInfo(total_block_count, &sdInfo);
///////////////////////////////////////////////////////////
// ??? Unit??§?????????
block_start = calc_unit(DISK_START, sdInfo);
block_offset = calc_unit(SYSTEM_PART_SIZE, sdInfo);
/* modify by cym 20131206 */
#if 0
block_offset = calc_unit(SYSTEM_PART_SIZE, sdInfo);
printf("block_start = %d, block_offset = %d\n", block_start, block_offset);
#else
if (flag)
block_offset = calc_unit((unsigned long long)
simple_strtoul(argv[3], NULL, 0) * 1024 * 1024, sdInfo);
else
block_offset = calc_unit(SYSTEM_PART_SIZE, sdInfo);
#endif
/* end modify */
partInfo[0].bootable = 0x00;
partInfo[0].partitionId = 0x83;
make_partitionInfo(block_start, block_offset, sdInfo, &partInfo[0]);
///////////////////////////////////////////////////////////
block_start += block_offset;
/* modify by cym 20131206 */
#if 0
if (strcmp(argv[2], "1") == 0)// TF card
block_offset = calc_unit(_300MB, sdInfo);
else
block_offset = calc_unit(USER_DATA_PART_SIZE, sdInfo);
#else
if (flag)
block_offset = calc_unit((unsigned long long)
simple_strtoul(argv[4], NULL, 0) * 1024 * 1024, sdInfo);
else
{
if (strcmp(argv[2], "1") == 0)// TF card
block_offset = calc_unit(_300MB, sdInfo);
else
block_offset = calc_unit(USER_DATA_PART_SIZE, sdInfo);
}
#endif
/* end modify */
partInfo[1].bootable = 0x00;
partInfo[1].partitionId = 0x83;
make_partitionInfo(block_start, block_offset, sdInfo, &partInfo[1]);
///////////////////////////////////////////////////////////
block_start += block_offset;
/* modify by cym 20131206 */
#if 0
; block_offset = calc_unit(CACHE_PART_SIZE, sdInfo);
#else
if(flag)
block_offset =
calc_unit((unsigned long long)
simple_strtoul(argv[5], NULL, 0) * 1024 * 1024, sdInfo);
else
block_offset = calc_unit(CACHE_PART_SIZE, sdInfo);
#endif
/* end modify */
partInfo[2].bootable = 0x00;
partInfo[2].partitionId = 0x83;
make_partitionInfo(block_start, block_offset, sdInfo, &partInfo[2]);
///////////////////////////////////////////////////////////
block_start += block_offset;
block_offset = BLOCK_END;
partInfo[3].bootable = 0x00;
partInfo[3].partitionId = 0x0C;
make_partitionInfo(block_start, block_offset, sdInfo, &partInfo[3]);
///////////////////////////////////////////////////////////
memset(mbr, 0x00, sizeof(*mbr) * 512); // liang, clean the mem again
mbr[510] = 0x55;
mbr[511] = 0xAA;
encode_partitionInfo(partInfo[0], &mbr[0x1CE]);
encode_partitionInfo(partInfo[1], &mbr[0x1DE]);
encode_partitionInfo(partInfo[2], &mbr[0x1EE]);
encode_partitionInfo(partInfo[3], &mbr[0x1BE]);
return 0;
}
從上(shang)述代(dai)碼中(zhong)我們可以看到，在(zai)執(zhi)行(xing)fdisk命令時(shi)打印的(de)四個分(fen)(fen)區(qu)(qu)實際(ji)上(shang)就(jiu)是(shi)(shi)partInfo的(de)四個元素，partInfo[0]代(dai)表的(de)是(shi)(shi)system分(fen)(fen)區(qu)(qu)，partInfo[1]代(dai)表的(de)是(shi)(shi)userdata分(fen)(fen)區(qu)(qu)， partInfo[2]代(dai)表的(de)是(shi)(shi)cache分(fen)(fen)區(qu)(qu)，剩下的(de)partInfo[3]是(shi)(shi)fat分(fen)(fen)區(qu)(qu)。所以在(zai)fdisk命令執(zhi)行(xing)完成后，出現的(de)四個分(fen)(fen)區(qu)(qu)1、2、3、4依(yi)次為fat、system、userdata、cache。
fastboot命令(ling)分析
我們在uboot狀態下執行fastboot命令(ling)的(de)(de)時候顯(xian)示的(de)(de)8個分(fen)區信息，跟前面咱們看(kan)到(dao)幾(ji)(ji)個分(fen)區又是什么樣的(de)(de)關系(xi)呢(ni)？實際上這里的(de)(de)bootloader、kernel、ramdisk、Recovery就是前面提到(dao)的(de)(de)那幾(ji)(ji)個分(fen)區，由uboot在啟動時調用mmc_init實現的(de)(de)。而后面的(de)(de)system、userdata、cache、fat四(si)個分(fen)區統稱為disk分(fen)區，同樣也是fdisk命令(ling)實現的(de)(de)分(fen)區信息。
