原创 彻底解决 u-boot 2011.03 DM9000A 第一次无法ping 的问题

   http://blog.ednchina.com/singlechip/2154280/message.aspx

   估计此方法不仅针对2011.03版本有用，对其他版本应该也有用，具体自己没测试过。

   针对DM9000A 的移植，网上一般都将DM9000X.C以下代码给屏蔽了。

    i = 0;
    while (!(phy_read(1) & 0x20)) { /* autonegation complete bit */
        udelay(1000);
        i++;
       if (i == 10000) {
          printf("could not establish link/n");
          return 0;
       }
    }

   这样就不会提示" could not establish link" ping的时候失败，但会出现第一次ping,或tftp时失败，每次都要终止，再次ping才能通，这对直接下载内核运行有所不变。

   后来自己通过增加延时，彻底解决了此问题，每次上电都能一次性ping成功，tftp也能一次成功。

   具体如下：

    i = 0;
    while (!(phy_read(1) & 0x20)) { /* autonegation complete bit */
        udelay(1000);
        i++;
       if (i == 500000) {
          printf("could not establish link/n");
          return 0;
       }
    }

    问题就解决了！

U-Boot 2011.03-dirty (Oct 24 2011 - 22:44:00)

DRAM:  64 MiB
Flash: 512 KiB
*** Warning - bad CRC, using default environment

In:    serial
Out:   serial
Err:   serial
Net:   dm9000
YY2440 # tftp 33000000 u-boot.bin
dm9000 i/o: 0x18000300, id: 0x90000a46
DM9000: running in 16 bit mode
MAC: 00:0c:20:02:0a:5b
operating at unknown: 7 mode
Using dm9000 device
TFTP from server 192.168.1.51; our IP address is 192.168.1.3
Filename 'u-boot.bin'.
Load address: 0x33000000
Loading: ##########
done
Bytes transferred = 134128 (20bf0 hex)

U-Boot 2011.03-dirty (Oct 24 2011 - 22:44:00)

DRAM:  64 MiB
Flash: 512 KiB
*** Warning - bad CRC, using default environment

In:    serial
Out:   serial
Err:   serial
Net:   dm9000
YY2440 # ping 192.168.1.51
dm9000 i/o: 0x18000300, id: 0x90000a46
DM9000: running in 16 bit mode
MAC: 00:0c:20:02:0a:5b
operating at unknown: 7 mode
Using dm9000 device
host 192.168.1.51 is alive
YY2440 #

每次出现 operating at unknown: 7 mode  对使用没有任何影响，所以我没屏蔽掉它。
/* see what we've got */
 lnk = phy_read(17) >> 12;
 printf("operating at ");
 switch (lnk) {
 case 1:
  printf("10M half duplex ");
  break;
 case 2:
  printf("10M full duplex ");
  break;
 case 4:
  printf("100M half duplex ");
  break;
 case 8:
  printf("100M full duplex ");
  break;
 default:
  printf("unknown: %d ", lnk);
  break;
 }
 printf("mode\n");

////////////////////////////////////////

修正  2011.10.25 20：15

 以上是针对用旧的u-boot 烧写新的 u-boot 到内存 运行的情况

如果 u-boot 是烧写到 nandflash 运行时，把

   i = 0;
    while (!(phy_read(1) & 0x20)) { /* autonegation complete bit */
        udelay(1000);
        i++;
       if (i == 10000) {
          printf("could not establish link/n");
          return 0;
       }
    }

屏蔽掉，ping  tftp 的响应速度非常快。。。。。而且第一次也能成功。

////////////////////////////////////////

U-Boot 2011.03-dirty (Oct 25 2011 - 20:08:54)

DRAM:  64 MiB
NAND:  NAND_ECC_NONE selected by board driver. This is not recommended !!
64 MiB
In:    serial
Out:   serial
Err:   serial
Net:   dm9000
Hit any key to stop autoboot:  0
YY2440 # ping 192.168.1.51
dm9000 i/o: 0x18000300, id: 0x90000a46
DM9000: running in 16 bit mode
MAC: 00:0c:20:02:0a:5b
operating at unknown: 0 mode
Using dm9000 device
host 192.168.1.51 is alive
YY2440 # tftp 30000000 u-boot.bin
dm9000 i/o: 0x18000300, id: 0x90000a46
DM9000: running in 16 bit mode
MAC: 00:0c:20:02:0a:5b
operating at unknown: 0 mode
Using dm9000 device
TFTP from server 192.168.1.51; our IP address is 192.168.1.3
Filename 'u-boot.bin'.
Load address: 0x30000000
Loading: ############
done
Bytes transferred = 170572 (29a4c hex)
YY2440 # nand erase 0 30000

NAND erase: device 0 offset 0x0, size 0x30000
Erasing at 0x2c000 -- 100% complete.
OK
YY2440 # nand write 30000000 0 30000

NAND write: device 0 offset 0x0, size 0x30000
 196608 bytes written: OK