include/asm/edac.h

0001 /* SPDX-License-Identifier: GPL-2.0-only */
0002 /*
0003  * Copyright 2011 Calxeda, Inc.
0004  * Based on PPC version Copyright 2007 MontaVista Software, Inc.
0005  */
0006 #ifndef ASM_EDAC_H
0007 #define ASM_EDAC_H
0008 /*
0009  * ECC atomic, DMA, SMP and interrupt safe scrub function.
0010  * Implements the per arch edac_atomic_scrub() that EDAC use for software
0011  * ECC scrubbing.  It reads memory and then writes back the original
0012  * value, allowing the hardware to detect and correct memory errors.
0013  */
0014
0015 static inline void edac_atomic_scrub(void *va, u32 size)
0016 {
0017 #if __LINUX_ARM_ARCH__ >= 6
0018     unsigned int *virt_addr = va;
0019     unsigned int temp, temp2;
0020     unsigned int i;
0021
0022     for (i = 0; i < size / sizeof(*virt_addr); i++, virt_addr++) {
0023         /* Very carefully read and write to memory atomically
0024          * so we are interrupt, DMA and SMP safe.
0025          */
0026         __asm__ __volatile__("\n"
0027             "1: ldrex   %0, [%2]\n"
0028             "   strex   %1, %0, [%2]\n"
0029             "   teq %1, #0\n"
0030             "   bne 1b\n"
0031             : "=&r"(temp), "=&r"(temp2)
0032             : "r"(virt_addr)
0033             : "cc");
0034     }
0035 #endif
0036 }
0037
0038 #endif