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 edac_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  */
  25
  26 static inline void edac_atomic_scrub(void *va, u32 size)
  27 {
  28 #if __LINUX_ARM_ARCH__ >= 6
  29         unsigned int *virt_addr = va;
  30         unsigned int temp, temp2;
  31         unsigned int i;
  32
  33         for (i = 0; i < size / sizeof(*virt_addr); i++, virt_addr++) {
  34                 /* Very carefully read and write to memory atomically
  35                  * so we are interrupt, DMA and SMP safe.
  36                  */
  37                 __asm__ __volatile__("\n"
  38                         "1:     ldrex   %0, [%2]\n"
  39                         "       strex   %1, %0, [%2]\n"
  40                         "       teq     %1, #0\n"
  41                         "       bne     1b\n"
  42                         : "=&r"(temp), "=&r"(temp2)
  43                         : "r"(virt_addr)
  44                         : "cc");
  45         }
  46 #endif
  47 }
  48
  49 #endif