ARM: 7201/1: add EDAC atomic_scrub function

/*

 * Copyright 2011 Calxeda, Inc.

 * Based on PPC version Copyright 2007 MontaVista Software, Inc.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms and conditions of the GNU General Public License,

 * version 2, as published by the Free Software Foundation.

 *

 * This program is distributed in the hope it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

 * more details.

 *

 * You should have received a copy of the GNU General Public License along with

 * this program.  If not, see <http://www.gnu.org/licenses/>.

 */

#ifndef ASM_EDAC_H

#define ASM_EDAC_H

/*

 * ECC atomic, DMA, SMP and interrupt safe scrub function.

 * Implements the per arch atomic_scrub() that EDAC use for software

 * ECC scrubbing.  It reads memory and then writes back the original

 * value, allowing the hardware to detect and correct memory errors.

 */

static inline void atomic_scrub(void *va, u32 size)

{

#if __LINUX_ARM_ARCH__ >= 6

	unsigned int *virt_addr = va;

	unsigned int temp, temp2;

	unsigned int i;

	for (i = 0; i < size / sizeof(*virt_addr); i++, virt_addr++) {

		/* Very carefully read and write to memory atomically

		 * so we are interrupt, DMA and SMP safe.

		 */

		__asm__ __volatile__("\n"

			"1:	ldrex	%0, [%2]\n"

			"	strex	%1, %0, [%2]\n"

			"	teq	%1, #0\n"

			"	bne	1b\n"

			: "=&r"(temp), "=&r"(temp2)

			: "r"(virt_addr)

			: "cc");

	}

#endif

}

#endif