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From: Lucas Stach <dev@lynxeye.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] arm: enable unaligned access on ARMv7
Date: Tue,  5 Jun 2012 19:47:31 +0200	[thread overview]
Message-ID: <1338918451-10126-1-git-send-email-dev@lynxeye.de> (raw)

Recent toolchains default to using the hardware feature for unaligned access on
ARM v7, rather than doing the software fallback. According to ARM this is safe
as all v7 implementations have to support this feature.
(http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0471c/BABJFFAE.html)

To avoid CPU hangs when doing unaligned memory access, we have to turn off
alignment checking in our CPU initialisation code.
(http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0491c/CIHCGCFD.html)

Signed-off-by: Lucas Stach <dev@lynxeye.de>
CC: Albert ARIBAUD <albert.u.boot@aribaud.net>
---
 arch/arm/cpu/armv7/start.S |    2 +-
 1 Datei ge?ndert, 1 Zeile hinzugef?gt(+), 1 Zeile entfernt(-)

diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
index 261835b..52f7f6e 100644
--- a/arch/arm/cpu/armv7/start.S
+++ b/arch/arm/cpu/armv7/start.S
@@ -316,7 +316,7 @@ ENTRY(cpu_init_cp15)
 	mrc	p15, 0, r0, c1, c0, 0
 	bic	r0, r0, #0x00002000	@ clear bits 13 (--V-)
 	bic	r0, r0, #0x00000007	@ clear bits 2:0 (-CAM)
-	orr	r0, r0, #0x00000002	@ set bit 1 (--A-) Align
+	bic	r0, r0, #0x00000002	@ clear bit 1 (--A-) Align
 	orr	r0, r0, #0x00000800	@ set bit 11 (Z---) BTB
 #ifdef CONFIG_SYS_ICACHE_OFF
 	bic	r0, r0, #0x00001000	@ clear bit 12 (I) I-cache
-- 
1.7.10.2

             reply	other threads:[~2012-06-05 17:47 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-05 17:47 Lucas Stach [this message]
2012-06-05 18:42 ` [U-Boot] [PATCH] arm: enable unaligned access on ARMv7 Stephen Warren
2012-06-05 19:06   ` Lucas Stach
2012-06-22  9:15     ` Albert ARIBAUD
2012-06-22  9:36       ` Lucas Stach
2012-06-22 11:16         ` Albert ARIBAUD
2012-06-22 11:47           ` Lucas Stach
2012-06-22 22:11             ` Aneesh V
2012-06-22 22:13               ` Aneesh V
2012-06-23  9:01                 ` Albert ARIBAUD
2012-06-23 17:43                   ` V, Aneesh
2012-06-25 20:34                     ` Albert ARIBAUD
2012-06-25 21:49                       ` Aneesh V
2012-06-25 22:02                         ` Wolfgang Denk
2012-06-23 19:50                   ` Måns Rullgård
2012-06-24  6:30                   ` Lucas Stach
     [not found]                     ` <20120625221741.3a32790e@lilith>
2012-06-25 21:34                       ` Lucas Stach
2012-06-26 20:56       ` Rob Herring
2012-06-27 10:14         ` Tetsuyuki Kobayashi
2012-07-02  9:42           ` [U-Boot] [PATCH] arm: armv7: add compile option -mno-unaligned-access if available Tetsuyuki Kobayashi
2012-07-02  9:53             ` Måns Rullgård
2012-07-02 15:16               ` Lucas Stach
2012-07-02 16:14                 ` Måns Rullgård
2012-07-03  7:10                   ` Tetsuyuki Kobayashi
2012-07-05  7:57                   ` Albert ARIBAUD
2012-07-18 21:37                     ` Albert ARIBAUD
2012-07-19  4:31                     ` Mike Frysinger
2012-07-19  4:29                   ` Mike Frysinger
2012-07-19  6:28                     ` Albert ARIBAUD
2012-07-19 14:27                       ` Mike Frysinger
2012-07-20  7:12                         ` Albert ARIBAUD
2012-07-12 15:12             ` Gary Thomas

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