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 39