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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;0 D4 N! k5 e' e: G
      sync ();( B* A& X. _% T* k/ f
      *addr = 0;
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      sync ();1 l& E$ z# |9 V% X! r/ X
      if ((val = *addr) != 0) {6 [, i, y; R3 h0 `9 S  ?
            /* Restore the original data before leaving the function.6 w9 t! U% b# Y  l+ Y( W0 `, e
               */
4 F8 v8 [; H' ]. P# s& k/ r             sync ();" V4 w& ]6 b3 d! K
            *addr = save;
: ^0 O$ A$ `  ?% g5 C. ?             for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {: Y( S9 m4 Q1 B& c# ^1 j
                     addr  = base + cnt;; M/ ~6 U. }+ n  m! |; `7 U
                     sync ();7 v* l& Z6 e( m3 _) {/ A& }/ |
                     *addr = save[--i];
' l' ?( Y" c. l7 m5 h             }5 ?( t" @6 s9 c
            return (0);
# n4 F! i4 u# |. m% }7 P       }
0 \; V$ q/ O0 ]3 o% r2 j  \: Z1 e/ l+ C: m. }; {
      for (cnt = 1; cnt < maxsize / sizeof (long); cnt <<= 1) {
! s' D- }1 D$ y5 |, F             addr = base + cnt;       /* pointer arith! */3 F8 q/ X, h' ~, l7 C- k
            val = *addr;
0 v, s" \- G( _1 T" ]             *addr = save[--i];
+ L8 Q+ J/ Q' @& p( w" l+ l             if (val != ~cnt) {/ v* Y' h& t3 a; y1 d1 h
                     size = cnt * sizeof (long);% Z# r! F3 f0 M& g8 m
                     /* Restore the original data before leaving the function.0 L! x$ _  H' `: y- L2 n
                     */
* V- Y# q" G; U3 n1 P8 K                      for (cnt <<= 1; cnt < maxsize / sizeof (long); cnt <<= 1) {
) `3 O, @) O( |, O! d9 F                               addr  = base + cnt;
" d! B7 j4 o& r1 x7 N1 j5 u2 F                               *addr = save[--i];
' [; u( ^7 e. l# e! K( w+ ^6 F                      }
, h: c* e8 g' R# ^3 C# {                      return (size);# P) S: f! p* a( o8 g1 }/ B1 b
            }
- z+ }( C9 a- U* F& ~       }
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      return (maxsize);/ i+ p7 _8 h) O1 o! p9 {$ f
}
; U! ^  j" \2 a0 `! q5 v1 G% v3 Sint dram_init(void)
: s! R: m9 U% B3 V4 W) q{
' X6 m9 n. D& h5 F) r8 z       /* dram_init must store complete ramsize in gd->ram_size */! P! v/ }* X$ b; s# k$ _
      gd->ram_size = get_ram_size(
9 W7 r6 |$ }! p8 ~3 i                      (void *)CONFIG_SYS_SDRAM_BASE,
( Q( C+ @( K7 p. `% T4 r+ E+ A8 ^                      CONFIG_MAX_RAM_BANK_SIZE);" ]& a# n) D6 s' [, D& P
      return 0;0 L& G4 P2 \" g1 I/ w8 N! I
}% u7 g4 c* m) w

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+ ?) a" ^2 j5 u' K9 e% C1 ^' [2 Z' z6 o* m# ^% D& }: ?7 n
FLASH是通过检查FLASH内部的ID识别容量，希望对您有帮助！
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