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标题: TL138 uboot是怎么区分配置两款核心板的 [打印本页]

作者: Mr.Loser 时间: 2014-9-11 09:33
标题: TL138 uboot是怎么区分配置两款核心板的
核心板1：DDR2 128M Byte NAND FLASH 4G bit
核心板2：DDR2 256M Byte NAND FLASH 8G bit
这两个核心板公共一个uboot，DDR2的配置肯定是不同的，uboot怎么检查到是哪个核心板，然后去执行相应的配置呢？

是不是通过读NAND FLASH的ID，两款核心板NAND FLASH不同，ID也不同，这样读到了ID就知道是哪个核心板了？

作者: 2532609929 时间: 2014-9-11 18:55
DDR通过检查最大有效地址来识别容量，具体请看uboot的common/memsize.c文件中的检查代码，也可以看如下：
/*
* Check memory range for valid RAM. A simple memory test determines
* the actually available RAM size between addresses `base' and
* `base + maxsize'.
*/
long get_ram_size(long *base, long maxsize)
{
      volatile long *addr;
      long          save[32];
      long          cnt;
      long          val;
      long          size;
      int          i = 0;

      for (cnt = (maxsize / sizeof (long)) >> 1; cnt > 0; cnt >>= 1) {
            addr = base + cnt;       /* pointer arith! */
            sync ();
            save[i++] = *addr;
            sync ();
            *addr = ~cnt;
      }

      addr = base;
      sync ();
      save = *addr;
# x# c; [' b; w       sync ();- M# ?. E* d% _; Q6 Y9 I' N
      *addr = 0;
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      sync ();% z- r/ D" X) D  N' N
      if ((val = *addr) != 0) {5 `3 K% E; N' `, |) ]
            /* Restore the original data before leaving the function.0 _8 e, C, p# g8 R7 V" ~! ^1 n& Y
               */
6 J! o- P* D; }2 J- j( y, S6 o             sync ();4 Z5 k6 z: L7 l+ Q% z: v4 P' ]
            *addr = save;
* l* }. V& n9 Y, v5 d             for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
# q+ r2 X9 d' c8 \- z, F                      addr  = base + cnt;* F1 Q. P1 o3 x/ X2 i* c
                     sync ();
/ y/ t2 [9 ^7 @                      *addr = save[--i];
9 z& S$ ~8 r# W; }" o8 @9 v             }/ t% k- @, ^2 R+ P9 a% a, t% z
            return (0);
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4 d) z/ z+ X4 W1 S       for (cnt = 1; cnt < maxsize / sizeof (long); cnt <<= 1) {
9 L- B) R) B: Z; p. L) U+ `             addr = base + cnt;       /* pointer arith! *// z5 h$ P- t: z3 t; c0 T
            val = *addr;! K# I; O8 X+ k4 c& R6 L
            *addr = save[--i];/ g5 ^; f( C# J2 J, A6 i1 h
            if (val != ~cnt) {
! X( A1 `/ \7 M                      size = cnt * sizeof (long);0 ?9 h8 a) z0 A/ s  s* p
                     /* Restore the original data before leaving the function.
7 L3 V+ |4 O; H; b$ U/ ~                      */
) Q1 F. U6 f, S# R                      for (cnt <<= 1; cnt < maxsize / sizeof (long); cnt <<= 1) {
, L4 k" L8 M% }( C+ f                               addr  = base + cnt;* D. G. P- t) v0 g
                              *addr = save[--i];. G0 q( o2 s3 ?/ t1 t4 d
                     }; Z; ~8 T. m0 J5 o
                     return (size);; x5 Z7 y8 F% |8 C- C: r9 n
            }
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      return (maxsize);2 v8 y( F* l3 h$ n6 V! p
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int dram_init(void)! k/ |' F, k. r: W2 E% p
{
  d& N1 k3 ]- ^; ?% Q2 a       /* dram_init must store complete ramsize in gd->ram_size */: ~$ m; s1 r, s9 B0 {) }- f
      gd->ram_size = get_ram_size(
0 O/ Q$ V8 Q! d4 h8 I% }. w                      (void *)CONFIG_SYS_SDRAM_BASE,1 w: u% z6 v2 Y* t6 \2 ?9 W8 N8 u* m( i
                     CONFIG_MAX_RAM_BANK_SIZE);, }# K- y* O5 U7 ~* x; U! q
      return 0;
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" n; Y4 M  @  U  QFLASH是通过检查FLASH内部的ID识别容量，希望对您有帮助！3 K6 ]3 i( ~' J) h) f
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