From 786a767465b12cb4c1a45421b12fbf6bff45b0ea Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Fri, 9 Dec 2011 17:58:35 +0100 Subject: [PATCH] ARM: 7201/1: add EDAC atomic_scrub function Add support for architecture specific EDAC atomic_scrub to ARM. Only ARMv6+ is implemented as ldrex/strex instructions are needed. Supporting EDAC on ARMv5 or earlier is unlikely at this point anyway. Signed-off-by: Rob Herring Signed-off-by: Russell King --- arch/arm/include/asm/edac.h | 48 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 arch/arm/include/asm/edac.h diff --git a/arch/arm/include/asm/edac.h b/arch/arm/include/asm/edac.h new file mode 100644 index 0000000..0df7a2c --- /dev/null +++ b/arch/arm/include/asm/edac.h @@ -0,0 +1,48 @@ +/* + * 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 . + */ +#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 -- 2.7.4