LXR linux/arch/arm/include/asm/edac.h

   1/*
   2 * Copyright 2011 Calxeda, Inc.
   3 * Based on PPC version Copyright 2007 MontaVista Software, Inc.
   4 *
   5 * This program is free software; you can redistribute it and/or modify it
   6 * under the terms and conditions of the GNU General Public License,
   7 * version 2, as published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope it will be useful, but WITHOUT
  10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12 * more details.
  13 *
  14 * You should have received a copy of the GNU General Public License along with
  15 * this program.  If not, see <http://www.gnu.org/licenses/>.
  16 */
  17#ifndef ASM_EDAC_H
  18#define ASM_EDAC_H
  19/*
  20 * ECC atomic, DMA, SMP and interrupt safe scrub function.
  21 * Implements the per arch atomic_scrub() that EDAC use for software
  22 * ECC scrubbing.  It reads memory and then writes back the original
  23 * value, allowing the hardware to detect and correct memory errors.
  24 */
  25static inline void atomic_scrub(void *va, u32 size)
  26{
  27#if __LINUX_ARM_ARCH__ >= 6
  28        unsigned int *virt_addr = va;
  29        unsigned int temp, temp2;
  30        unsigned int i;
  31
  32        for (i = 0; i < size / sizeof(*virt_addr); i++, virt_addr++) {
  33                /* Very carefully read and write to memory atomically
  34                 * so we are interrupt, DMA and SMP safe.
  35                 */
  36                __asm__ __volatile__("\n"
  37                        "1:     ldrex   %0, [%2]\n"
  38                        "       strex   %1, %0, [%2]\n"
  39                        "       teq     %1, #0\n"
  40                        "       bne     1b\n"
  41                        : "=&r"(temp), "=&r"(temp2)
  42                        : "r"(virt_addr)
  43                        : "cc");
  44        }
  45#endif
  46}
  47
  48#endif
  49