u-boot-2014.10移植第23天----nand flash启动(一)

时间:2022-07-06 17:14:41

硬件平台:tq2440

开发环境:Ubuntu-3.11

u-boot版本:2014.10

本文允许转载,请注明出处:http://blog.csdn.net/fulinus

在Nand flash中保存环境变量

u-boot中的环境变量可以通过pri命令可以查看,可以通过set(setenv)命令设置一个参数,设置之后的参数仅仅是保存在SDRAM中,掉电后丢失,

使用save命令可以保存参数到Nor flash或Nand flash中去,但是u-boot默认是保存到Nor flash中去,下面修改u-boot,使其保存的环境变量保存到

Nand flash中去。

在include/configs/tq2440.h文件中修改:

+ #if NONE_FLAG                  
#define CONFIG_ENV_ADDR         (CONFIG_SYS_FLASH_BASE + 0x070000)
#define CONFIG_ENV_IS_IN_FLASH 
#define CONFIG_ENV_SIZE         0x10000
+ #else                          
+ #define CONFIG_ENV_IS_IN_NAND  
+ #define CONFIG_ENV_OFFSET       0x40000 /* 256K for u-boot */
+ #define CONFIG_ENV_SIZE         0x20000 /* 128K for environment */
+ #endif

编译、烧录到SDRAM中去,运行。演示:

*** Warning - bad CRC, using default environment
这条提示说明没有没有环境变量,使用默认的环境变量,使用pri查看有哪些环境变量:

[TQ2440 #] pri
baudrate=115200
bootdelay=5
ethact=dm9000
ipaddr=10.0.0.110
netmask=255.255.255.0
serverip=10.0.0.1
stderr=serial
stdin=serial
stdout=serial

使用save命令保存默认的环境变量:

[TQ2440 #] save
Saving Environment to NAND...
Erasing NAND...
Erasing at 0x5c000 -- 100% complete.
Writing to NAND... OK
[TQ2440 #] 
[TQ2440 #] nand dump 40000
Page 00040000 dump:
        fd 4a d7 7a 62 61 75 64  72 61 74 65 3d 31 31 35
        32 30 30 00 62 6f 6f 74  64 65 6c 61 79 3d 35 00
        65 74 68 61 63 74 3d 64  6d 39 30 30 30 00 69 70
        61 64 64 72 3d 31 30 2e  30 2e 30 2e 31 31 30 00
        6e 65 74 6d 61 73 6b 3d  32 35 35 2e 32 35 35 2e
        32 35 35 2e 30 00 73 65  72 76 65 72 69 70 3d 31
        30 2e 30 2e 30 2e 31 00  73 74 64 65 72 72 3d 73
        65 72 69 61 6c 00 73 74  64 69 6e 3d 73 65 72 69
        61 6c 00 73 74 64 6f 75  74 3d 73 65 72 69 61 6c

        00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00

再次烧录运行,就没有上面的警告了。在tq2440.h头文件中设置环境变量:

#define CONFIG_NETMASK      255.255.255.0
+ #define CONFIG_IPADDR       192.168.169.9
+ #define CONFIG_SERVERIP     192.168.169.8
+ #define CONFIG_ETHADDR      12:34:56:78:9A:BC

添加mtd分区命令

修改tq2440.h文件,使能该命令宏:

/*
 * File system
 */
+ #if NONE_FLAG
#define CONFIG_CMD_FAT
#define CONFIG_CMD_EXT2
#define CONFIG_CMD_UBI
#define CONFIG_CMD_UBIFS
#define CONFIG_CMD_MTDPARTS
#define CONFIG_MTD_DEVICE
#define CONFIG_MTD_PARTITIONS
#define CONFIG_YAFFS2
#define CONFIG_RBTREE
+ #else
+ #define CONFIG_CMD_MTDPARTS
+ define CONFIG_MTD_DEVICE
#endif

编译、烧录到SDRAM中去,运行。演示:

[TQ2440 #] mtd
mtdids not defined, no default present
上述提示位于common/cmd_mtdparts.c文件1751行
if (mtdids_default) {
            debug("mtdids variable not defined, using default\n");
            ids = mtdids_default;
            setenv("mtdids", (char *)ids);
        } else {
            printf("mtdids not defined, no default present\n");
            return 1;
        }
mtdids_default为假时错误打印该条信息,mtdids_default变量在该文件中定义如下:

/* default values for mtdids and mtdparts variables */
#if defined(MTDIDS_DEFAULT)
static const char *const mtdids_default = MTDIDS_DEFAULT;
#else
static const char *const mtdids_default = NULL;
#endif

#if defined(MTDPARTS_DEFAULT)
static const char *const mtdparts_default = MTDPARTS_DEFAULT;
#else
static const char *const mtdparts_default = NULL;
#endif
现在这里的mtdids_default=NULL,因为未定义MTDIDS_DEFAULT宏。下面定义MTDIDS_DEFAULT宏和MTDPARTS_DEFAULT宏,参考该文件中最上面注释部分内容:

 * Examples:
 *
 * 1 NOR Flash, with 1 single writable partition:
 * mtdids=nor0=edb7312-nor
 * mtdparts=mtdparts=edb7312-nor:-
 *
 * 1 NOR Flash with 2 partitions, 1 NAND with one
 * mtdids=nor0=edb7312-nor,nand0=edb7312-nand
 * mtdparts=mtdparts=edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
 *
 */

在tq2440.h头文件中定义:

#else
#define CONFIG_CMD_MTDPARTS
#define CONFIG_MTD_DEVICE
+ #define MTDIDS_DEFAULT "nand0=tq2440-0"
+ #define MTDPARTS_DEFAULT "mtdparts=tq2440-0:1m(u-boot)," \
+     "4m(kernel)," \
+     "-(rootfs)"
#endif
编译、烧录到SDRAM中去,运行。演示:

[TQ2440 #] pri
baudrate=115200
bootdelay=5
ethact=dm9000
ethaddr=12:34:56:78:9A:BC
ipaddr=192.168.169.9
netmask=255.255.255.0
serverip=192.168.169.8
stderr=serial
stdin=serial
stdout=serial

[TQ2440 #] mtdparts
mtdparts variable not set, see 'help mtdparts'
no partitions defined


defaults:
mtdids  : nand0=tq2440-0
mtdparts: mtdparts=tq2440-0:1m(u-boot),4m(kernel),-(rootfs)
[TQ2440 #] mtdparts default
[TQ2440 #] save
[TQ2440 #] mtdparts

device nand0 <tq2440-0>, # parts = 3
 #: name                size            offset          mask_flags
 0: u-boot              0x00100000      0x00000000      0
 1: kernel              0x00400000      0x00100000      0
 2: rootfs              0x03b00000      0x00500000      0

active partition: nand0,0 - (u-boot) 0x00100000 @ 0x00000000