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