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 
edac_atomic_scrub(void * va,u32 size)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