arch/powerpc/lib/memcpy_mpc5200.c

   1 /*
   2  * (C) Copyright 2010
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 /*
   9  * This is a workaround for issues on the MPC5200, where unaligned
  10  * 32-bit-accesses to the local bus will deliver corrupted data. This
  11  * happens for example when trying to use memcpy() from an odd NOR
  12  * flash address; the behaviour can be also seen when using "md" on an
  13  * odd NOR flash address (but there it is not a bug in U-Boot, which
  14  * only shows the behaviour of this processor).
  15  *
  16  * For memcpy(), we test if either the source or the target address
  17  * are not 32 bit aligned, and - if so - if the source address is in
  18  * NOR flash: in this case we perform a byte-wise (slow) then; for
  19  * aligned operations of non-flash areas we use the optimized (fast)
  20  * real __memcpy().  This way we minimize the performance impact of
  21  * this workaround.
  22  *
  23  */
  24
  25 #include <common.h>
  26 #include <flash.h>
  27 #include <linux/types.h>
  28
  29 void *memcpy(void *trg, const void *src, size_t len)
  30 {
  31         extern void* __memcpy(void *, const void *, size_t);
  32         char *s = (char *)src;
  33         char *t = (char *)trg;
  34         void *dest = (void *)trg;
  35
  36         /*
  37          * Check is source address is in flash:
  38          * If not, we use the fast assembler code
  39          */
  40         if (((((unsigned long)s & 3) == 0)      /* source aligned  */
  41                 &&                              /*      AND        */
  42              (((unsigned long)t & 3) == 0))     /* target aligned, */
  43                 ||                              /*      or         */
  44             (addr2info((ulong)s) == NULL)) {    /* source not in flash */
  45                 return __memcpy(trg, src, len);
  46         }
  47
  48         /*
  49          * Copying from flash, perform byte by byte copy.
  50          */
  51         while (len-- > 0)
  52                 *t++ = *s++;
  53
  54         return dest;
  55 }