UBOOT-2012-10在OK6410平台的移植（十三）完善功能

1.完善saveenv功能（ENV保存于NAND Flash）

在执行saveenv命令时，出现“MTD Erase failure: -22”的问题

原因是erase是nand的整个block，而设置的CONFIG_ENV_SIZE小于block。于是设置：

#define CONFIG_ENV_OFFSET   0x0080000

#define CONFIG_ENV_SIZE        0x80000

该问题解决了，但启动后一直出现“bad CRC,using default environment”

通过查找发现，uboot没有找到复制到CONFIG_NAND_ENV_DST处的环境变量。

我的uboot image放在NAND的第一个BLOCK（512K），而ENV放在第二块BLOCK。

系统启动第一阶段时env_init会查找指到CONFIG_NAND_ENV_DST处的环境变量，如果没有找到则gd->env_valid=0

系统启动第二阶段的env_relocat根据gd->env_valid=0而env_set_defaut("!bad CRC");

再来看nand启动的nand_boot函数，该函数里面只有

nandll_read_blocks(CONFIG_SYS_PHY_UBOOT_BASE,CONFIG_SYS_UBOOT_SIZE, CONFIG_SYS_NAND_PAGE_SIZE);

进一步发现nand_boot启动过程只复制了第一个block到内存（uboot image），所以还需要 把第二个block也复制到内存CONFIG_NAND_ENV_DST处。

修改nand_boot.c中几个函数，内容如下：

#include 
#include 
#include 
#include 

#define NAND_DISABLE_CE()	(NFCONT_REG |= (1 << 1))
#define NAND_ENABLE_CE()	(NFCONT_REG &= ~(1 << 1))
#define NF_TRANSRnB()		do { while(!(NFSTAT_REG & (1 << 0))); } while(0)

static void nandll_read_page (uchar *buf, ulong addr, uint nand_page_size)
{
    int i;
	/*
    int page_size = 512;

    if (large_block==1)
        page_size = 2048;
    if (large_block==2)
        page_size = 4096;
    if(large_block==3)
        page_size = 8192;
    */
    NAND_ENABLE_CE();

    NFCMD_REG = NAND_CMD_READ0;

    /* Write Address */
    NFADDR_REG = 0;

    if (nand_page_size>=2048)
        NFADDR_REG = 0;

    NFADDR_REG = (addr) & 0xff;
    NFADDR_REG = (addr >> 8) & 0xff;
    NFADDR_REG = (addr >> 16) & 0xff;

    if (nand_page_size>=2048)
        NFCMD_REG = NAND_CMD_READSTART;

    NF_TRANSRnB();

    /* for compatibility(2460). u32 cannot be used. by scsuh */
    for(i=0; i < nand_page_size; i++) {
        *buf++ = NFDATA8_REG;
    }

    NAND_DISABLE_CE();
    //return 0;
}

/*
 * Read data from NAND.
 */
static void nandll_read_blocks (ulong dst_addr, ulong offs,ulong read_size, uint nand_page_size)
{
    unsigned char *buf = (unsigned char *)dst_addr;
    unsigned i;
    unsigned page_shift = 9;
	unsigned int block, lastblock;
	unsigned int page;

    if(nand_page_size == 4096) 
    {
        page_shift = 12;//4k page

		block = offs / CONFIG_SYS_NAND_BLOCK_SIZE;
		lastblock = (offs + read_size - 1) / CONFIG_SYS_NAND_BLOCK_SIZE;
		page = (offs % CONFIG_SYS_NAND_BLOCK_SIZE) / CONFIG_SYS_NAND_PAGE_SIZE;
		if(block==0)//we always use first block for uboot image
 		{
           /* Read step 1 */
		   for (i = 2; i < 4; i++, buf+=(1<<(page_shift-1)))
            nandll_read_page(buf, i, nand_page_size);
		   /* Read step 2 */
           for (i = 4; i < (read_size>>page_shift); i++, buf+=(1<>page_shift); i++, buf+=(1<>page_shift); i++, buf+=(1<240KB because of U-Boot size increase. by scsuh
     * So, read 0x3c000 bytes not 0x20000(128KB).
     */
    //led test
    writel(0x0023,0x7f008824);
    nandll_read_blocks(CONFIG_SYS_PHY_UBOOT_BASE,
                       CONFIG_SYS_NAND_U_BOOT_OFFS,
                       CONFIG_SYS_UBOOT_SIZE, 
                       CONFIG_SYS_NAND_PAGE_SIZE);
	#ifdef CONFIG_NAND_ENV_DST
	//led test
    writel(0x002a,0x7f008824);
	nandll_read_blocks(CONFIG_NAND_ENV_DST,
	                   CONFIG_ENV_OFFSET,
	                   CONFIG_ENV_SIZE,
	                   CONFIG_SYS_NAND_PAGE_SIZE);
    #endif
	uboot = (void *)CONFIG_SYS_PHY_UBOOT_BASE;
	(*uboot)();
}

重新启动后，bad CRC的提示没有了。

#md 57e80000可以查看到环境变量都已经复制到内存，从而解决了该问题。