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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;
, m( q0 ]+ h/ j( X       sync ();
# Z- v3 [7 [2 M+ `       *addr = 0;
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      sync ();% k2 G& \3 w3 H
      if ((val = *addr) != 0) {
  Q. z$ t4 B$ ~; x7 o             /* Restore the original data before leaving the function.4 x' e. ^+ H$ ~
               */: `& L0 U/ s, t4 S) s9 }# ^# u
            sync ();
2 q" h7 Y+ n# i# G, a             *addr = save;
# o! a* h  ~6 a             for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
8 o7 H) M; K- T; B: K5 C                      addr  = base + cnt;& p) f. e6 z' o* @# g+ b/ x6 S8 Y
                     sync ();/ [) B" Y( Z  O9 }  l1 d- |
                     *addr = save[--i];
& Y, i: k2 L% z9 ~/ Y) X. A; J             }% w+ m' _3 X4 b, y
            return (0);
8 {  Q9 ^3 I* @, q& `# q       }
1 G' [% a" i% B8 m/ f
9 U- |3 J9 I9 \       for (cnt = 1; cnt < maxsize / sizeof (long); cnt <<= 1) {
. f( V$ s$ Z- d; Y, H             addr = base + cnt;       /* pointer arith! */
2 Z- b3 m: \% I2 E1 Q+ x             val = *addr;% E  i7 p' U' ^
            *addr = save[--i];# k4 z* M) A& ]. d( e6 ?
            if (val != ~cnt) {
' y! P) `+ g$ h% B- n                      size = cnt * sizeof (long);
. u, m7 X# `1 z" X/ p                      /* Restore the original data before leaving the function.
' v- n5 r4 N9 K, u6 G9 U' K9 j                      */
" t' c& v0 L# E1 m1 K+ C' V                      for (cnt <<= 1; cnt < maxsize / sizeof (long); cnt <<= 1) {
% |$ [) ~7 D; g                               addr  = base + cnt;5 ?0 V4 h7 u' H# Y, \" V( h
                              *addr = save[--i];' e; ^/ ?2 R7 y2 f4 V, s
                     }" a( Q4 Y( D2 F. f6 w# H
                     return (size);
8 Z. V9 b( R8 z4 M             }+ H% Q5 r+ I7 l: o
      }( J0 F. h  Z1 o9 a: B% U  g6 y1 t
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      return (maxsize);
9 y$ I4 [# p0 n* y3 Z}
, \$ S0 F, S8 D& q7 sint dram_init(void)0 ]7 R, P/ i/ C& ~- ^' Z; |
{
; H) M. V% J9 ^       /* dram_init must store complete ramsize in gd->ram_size */, }4 O& b# q1 L; k& F- g
      gd->ram_size = get_ram_size(3 z  W3 S0 @4 ^5 W9 j
                     (void *)CONFIG_SYS_SDRAM_BASE,
: a6 G6 M# r# U! g                      CONFIG_MAX_RAM_BANK_SIZE);
5 x7 F: n6 A2 v) E( G       return 0;
/ b/ w  D. e) ^- M! j/ K0 ?8 u}
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2 C9 D0 `: Q' p/ E# }7 O" o; O) J
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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