xref: /openbmc/linux/arch/arm/include/asm/edac.h (revision ba61bb17)
1 /*
2  * Copyright 2011 Calxeda, Inc.
3  * Based on PPC version Copyright 2007 MontaVista Software, Inc.
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms and conditions of the GNU General Public License,
7  * version 2, as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
12  * more details.
13  *
14  * You should have received a copy of the GNU General Public License along with
15  * this program.  If not, see <http://www.gnu.org/licenses/>.
16  */
17 #ifndef ASM_EDAC_H
18 #define ASM_EDAC_H
19 /*
20  * ECC atomic, DMA, SMP and interrupt safe scrub function.
21  * Implements the per arch edac_atomic_scrub() that EDAC use for software
22  * ECC scrubbing.  It reads memory and then writes back the original
23  * value, allowing the hardware to detect and correct memory errors.
24  */
25 
26 static inline void edac_atomic_scrub(void *va, u32 size)
27 {
28 #if __LINUX_ARM_ARCH__ >= 6
29 	unsigned int *virt_addr = va;
30 	unsigned int temp, temp2;
31 	unsigned int i;
32 
33 	for (i = 0; i < size / sizeof(*virt_addr); i++, virt_addr++) {
34 		/* Very carefully read and write to memory atomically
35 		 * so we are interrupt, DMA and SMP safe.
36 		 */
37 		__asm__ __volatile__("\n"
38 			"1:	ldrex	%0, [%2]\n"
39 			"	strex	%1, %0, [%2]\n"
40 			"	teq	%1, #0\n"
41 			"	bne	1b\n"
42 			: "=&r"(temp), "=&r"(temp2)
43 			: "r"(virt_addr)
44 			: "cc");
45 	}
46 #endif
47 }
48 
49 #endif
50