linux/arch/powerpc/include/asm/edac.h
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   1/*
   2 * PPC EDAC common defs
   3 *
   4 * Author: Dave Jiang <djiang@mvista.com>
   5 *
   6 * 2007 (c) MontaVista Software, Inc. This file is licensed under
   7 * the terms of the GNU General Public License version 2. This program
   8 * is licensed "as is" without any warranty of any kind, whether express
   9 * or implied.
  10 */
  11#ifndef ASM_EDAC_H
  12#define ASM_EDAC_H
  13/*
  14 * ECC atomic, DMA, SMP and interrupt safe scrub function.
  15 * Implements the per arch atomic_scrub() that EDAC use for software
  16 * ECC scrubbing.  It reads memory and then writes back the original
  17 * value, allowing the hardware to detect and correct memory errors.
  18 */
  19static __inline__ void atomic_scrub(void *va, u32 size)
  20{
  21        unsigned int *virt_addr = va;
  22        unsigned int temp;
  23        unsigned int i;
  24
  25        for (i = 0; i < size / sizeof(*virt_addr); i++, virt_addr++) {
  26                /* Very carefully read and write to memory atomically
  27                 * so we are interrupt, DMA and SMP safe.
  28                 */
  29                __asm__ __volatile__ ("\n\
  30                                1:      lwarx   %0,0,%1\n\
  31                                        stwcx.  %0,0,%1\n\
  32                                        bne-    1b\n\
  33                                        isync"
  34                                        : "=&r"(temp)
  35                                        : "r"(virt_addr)
  36                                        : "cr0", "memory");
  37        }
  38}
  39
  40#endif
  41