Linux Archive

Linux Archive (http://www.linux-archive.org/)
-   Ubuntu Kernel Team (http://www.linux-archive.org/ubuntu-kernel-team/)
-   -   ARM: 7201/1: add EDAC atomic_scrub function (http://www.linux-archive.org/ubuntu-kernel-team/677752-arm-7201-1-add-edac-atomic_scrub-function.html)

Ike Panhc 06-27-2012 12:49 PM

ARM: 7201/1: add EDAC atomic_scrub function
 
From: Rob Herring <rob.herring@calxeda.com>

BugLink: http://launchpad.net/bugs/1008345

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 <rob.herring@calxeda.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
(cherry picked from commit 786a767465b12cb4c1a45421b12fbf6bff45b0ea)

Signed-off-by: Ike Panhc <ike.pan@canonical.com>
---
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 <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__("
"
+ "1: ldrex %0, [%2]
"
+ " strex %1, %0, [%2]
"
+ " teq %1, #0
"
+ " bne 1b
"
+ : "=&r"(temp), "=&r"(temp2)
+ : "r"(virt_addr)
+ : "cc");
+ }
+#endif
+}
+
+#endif
--
1.7.9.5


--
kernel-team mailing list
kernel-team@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/kernel-team


All times are GMT. The time now is 10:58 PM.

VBulletin, Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO ©2007, Crawlability, Inc.