arch/arm/include/asm/edac.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright 2011 Calxeda, Inc.
   4  * Based on PPC version Copyright 2007 MontaVista Software, Inc.
   5  */
   6 #ifndef ASM_EDAC_H
   7 #define ASM_EDAC_H
   8 /*
   9  * ECC atomic, DMA, SMP and interrupt safe scrub function.
  10  * Implements the per arch edac_atomic_scrub() that EDAC use for software
  11  * ECC scrubbing.  It reads memory and then writes back the original
  12  * value, allowing the hardware to detect and correct memory errors.
  13  */
  14
  15 static inline void edac_atomic_scrub(void *va, u32 size)
  16 {
  17 #if __LINUX_ARM_ARCH__ >= 6
  18         unsigned int *virt_addr = va;
  19         unsigned int temp, temp2;
  20         unsigned int i;
  21
  22         for (i = 0; i < size / sizeof(*virt_addr); i++, virt_addr++) {
  23                 /* Very carefully read and write to memory atomically
  24                  * so we are interrupt, DMA and SMP safe.
  25                  */
  26                 __asm__ __volatile__("\n"
  27                         "1:     ldrex   %0, [%2]\n"
  28                         "       strex   %1, %0, [%2]\n"
  29                         "       teq     %1, #0\n"
  30                         "       bne     1b\n"
  31                         : "=&r"(temp), "=&r"(temp2)
  32                         : "r"(virt_addr)
  33                         : "cc");
  34         }
  35 #endif
  36 }
  37
  38 #endif