uboot/arch/powerpc/lib/memcpy_mpc5200.c
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   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
  29void *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 *)src;
  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}
  56