mini2440移植uboot 2014.04(三）

我修改的代码已经上传到github上，地址：https://github.com/qiaoyuguo/u-boot-2014.04-mini2440.git

参考文档： s3c2440手册（下载地址） mini2440电路图（下载地址） K9F1G08数据手册（下载地址）

参考文章：《mini2440移植uboot 2011.03(下)》

前两篇博文： 《mini2440移植uboot 2014.04(一)》

《mini2440移植uboot 2014.04(二)》

（五）添加nand flash支持

主要是基于参考mini2440 自带的uboot源代码进行修改。

用官方uboot启动时，得到的输出信息是128MiB的nand flash。查看芯片电路图可以知道是K9F系列芯片，而128MiB的芯片只能是K9F1G08（128Mx8bits)。

在上一节执行uboot时，关于nand flash的显示信息如下：

NAND:  board_nand_init()
end of nand_init
hwcontrol(): 0xff 0x83
hwcontrol(): 0xffffffff 0x81
dev_ready
hwcontrol(): 0x90 0x83
hwcontrol(): 0x00 0x85
hwcontrol(): 0xffffffff 0x81
dev_ready
hwcontrol(): 0x90 0x83
hwcontrol(): 0x00 0x85
hwcontrol(): 0xffffffff 0x81
dev_ready
hwcontrol(): 0xffffffff 0x80
 MiB

明显没有检测到nand flash.
整个调用入口是nand_init->nand_init_chip->board_nand_init，而board_nand_init函数位于drivers/mtd/nand/s3c2410_nand.c中 。

首先需要考虑的就是几个变量的值：tacls、twrph0、twrph1。

参考文章《uboot中nand flash控制器参数TACLS、TWRPH0和TWRPH1的确定(基于K9F2G08U0B)》,这三个值是根据时序来计算出来的。

根据K9F1G08手册第17页和第10页以及s3c2440手册587页，可以知道tacls=tCLS>12ns,twrph0=tWP>12ns,twrph1=tCLH>5ns。

而nand flash是根据HCLK时钟来计算，根据1:4:8的分频，HCLK=100MHZ,每个时钟=10ns.

可以将这三个值分别设置成2、2、1即可，但是为了保持和官方版本一致，我仍将其值设置成4、2、0.

根据2440手册第226页，其NFCONT寄存器中每一位的含义与s3c2410中的大部分都不相同，需要进行相应的修改。

我只是将mini2440中的uboot和当前代码合并，修改代码如下：

#ifdef CONFIG_S3C2410
#define S3C2410_NFCONF_EN          (1<<15)
#define S3C2410_NFCONF_512BYTE     (1<<14)
#define S3C2410_NFCONF_4STEP       (1<<13)
#define S3C2410_NFCONF_INITECC     (1<<12)
#define S3C2410_NFCONF_nFCE        (1<<11)
#define S3C2410_NFCONF_TACLS(x)    ((x)<<8)
#define S3C2410_NFCONF_TWRPH0(x)   ((x)<<4)
#define S3C2410_NFCONF_TWRPH1(x)   ((x)<<0)

#define S3C2410_ADDR_NALE 4
#define S3C2410_ADDR_NCLE 8
#endif

#ifdef CONFIG_S3C2440
#define S3C2410_NFCONT_EN          (1<<0)
#define S3C2410_NFCONT_INITECC     (1<<4)
#define S3C2410_NFCONT_nFCE        (1<<1)
#define S3C2410_NFCONT_MAINECCLOCK (1<<5)
#define S3C2410_NFCONF_TACLS(x)    ((x)<<12)
#define S3C2410_NFCONF_TWRPH0(x)   ((x)<<8)
#define S3C2410_NFCONF_TWRPH1(x)   ((x)<<4)  

#define S3C2410_ADDR_NALE 0x08
#define S3C2410_ADDR_NCLE 0x0c
#endif

#if defined(CONFIG_S3C2410)
                if (ctrl & NAND_NCE)
                        writel(readl(&nand->nfconf) & ~S3C2410_NFCONF_nFCE,
                               &nand->nfconf);
                else
                        writel(readl(&nand->nfconf) | S3C2410_NFCONF_nFCE,
                               &nand->nfconf);
        }
#endif
#if defined(CONFIG_S3C2440)
                if (ctrl & NAND_NCE)
                        writel(readl(&nand->nfconf) & ~S3C2410_NFCONT_nFCE,
                               &nand->nfconf);
                else
                        writel(readl(&nand->nfconf) | S3C2410_NFCONT_nFCE,
                               &nand->nfconf);
        }
#endif
#if defined(CONFIG_S3C2410)
        writel(readl(&nand->nfconf) | S3C2410_NFCONF_INITECC, &nand->nfconf);
#endif

#if defined(CONFIG_S3C2440)
        writel(readl(&nand->nfconf) | S3C2410_NFCONT_INITECC, &nand->nfconf);
#endif

#if defined(CONFIG_S3C2410)
        /* initialize hardware */
#if defined(CONFIG_S3C24XX_CUSTOM_NAND_TIMING)
        tacls  = CONFIG_S3C24XX_TACLS;
        twrph0 = CONFIG_S3C24XX_TWRPH0;
        twrph1 =  CONFIG_S3C24XX_TWRPH1;
#else
        tacls = 4;
        twrph0 = 8;
        twrph1 = 8;
#endif
#endif

#if defined(CONFIG_S3C2440)
        tacls = 4;
        twrph0 = 2;
        twrph1 = 0;

        cfg = 0;
        cfg |= S3C2410_NFCONF_TACLS(tacls - 1);
        cfg |= S3C2410_NFCONF_TWRPH0(twrph0 - 1);
        cfg |= S3C2410_NFCONF_TWRPH1(twrph1 - 1);
        writel(cfg, &nand_reg->nfconf);

        cfg = (1<<4)|(1<<0);
    writel(cfg, &nand_reg->nfcont);
#else
        cfg = S3C2410_NFCONF_EN;
        cfg |= S3C2410_NFCONF_TACLS(tacls - 1);
        cfg |= S3C2410_NFCONF_TWRPH0(twrph0 - 1);
        cfg |= S3C2410_NFCONF_TWRPH1(twrph1 - 1);
        writel(cfg, &nand_reg->nfconf);
        writel(cfg, &nand_reg->nfcont);
#endif

重新编译加载到mini2440,得到输出信息如下：

NAND:  board_nand_init()
end of nand_init
hwcontrol(): 0xff 0x83
hwcontrol(): 0xffffffff 0x81
dev_ready
hwcontrol(): 0x90 0x83
hwcontrol(): 0x00 0x85
hwcontrol(): 0xffffffff 0x81
dev_ready
hwcontrol(): 0x90 0x83
hwcontrol(): 0x00 0x85
hwcontrol(): 0xffffffff 0x81
dev_ready
hwcontrol(): 0xffffffff 0x80
 MiB

执行一些命令，得到的输出信息：

SMDK2410 # nand info

Device : nand0, sector size  KiB
  Page size       b
  OOB size          b
  Erase size    b
Initial value for argc=
Final value for argc=
Initial value for argc=
Final value for argc=
Initial value for argc=
Final value for argc=

貌似nand flash基本支持已经完成了，后面使用有问题了再修改代码。

执行了几个nand命令，重新加载uboot到mini2440,却出现下面的错误：

U-Boot 2014.04-g9541fe9-dirty (Jun   - ::)

U-Boot code: 33E80000 -> 33EF9ED0  BSS: -> 33F488D0
CPUID:
FCLK:       MHz
HCLK:  101.250 MHz
PCLK:   50.625 MHz
monitor len: 000C88D0
ramsize:
TLB table from 33ff0000 to 33ff4000
Top of RAM usable for U-Boot at: 33ff0000
Reserving 802k for U-Boot at: 33f27000
Reserving 4160k for malloc() at: 33b17000
Reserving  Bytes for Board Info at: 33b16fe0
Reserving  Bytes for Global Data at: 33b16f40
New Stack Pointer is: 33b16f30
RAM Configuration:
Bank #:   MiB
addr=33f27000,_start=33e80000
relocation Offset is: 000a7000
WARNING: Caches not enabled
monitor flash len: 000846C0
dram_bank_mmu_setup: bank:
Now running in RAM - U-Boot at: 33f27000
Flash: fwc addr  cmd f0 00f0 16bit x  bit
fwc addr 0000aaaa cmd aa 00aa 16bit x  bit
fwc addr  cmd   16bit x  bit
fwc addr 0000aaaa cmd   16bit x  bit
fwc addr  cmd f0 00f0 16bit x  bit
JEDEC PROBE: ID f0 ffff
fwc addr  cmd ff 00ff 16bit x  bit
fwc addr  cmd   16bit x  bit
fwc addr  cmd ff 00ff 16bit x  bit
JEDEC PROBE: ID  ffff
*** failed ***
### ERROR ### Please RESET the board ###

居然又无法检测到nor flash了。我折腾了好一会儿，将nand flash全部擦除，然后将官方的uboot重新加载进来，

之后再加载自己的uboot，能正常进入到uboot命令行了。