flag@omap:~$ dmesg | grep -A 1 L310
[ 0.219024] L310 cache controller enabled
[ 0.219055] l2x0: 16 ways, CACHE_ID 0x410000c4, AUX_CTRL 0x7e470000,
Cache size: 1048576 B
^^^^^^^^^^^^^^
according to [1], that means Panda has a r3p0 L310 L2 controller.
[flag@newluxor linux-linaro-2.6.38]$ git show 885028e
commit 885028e4ba4caf49d565c96481e1a05220ecb517
Author: Srinidhi Kasagar <[email protected]>
Date: Thu Feb 17 07:03:51 2011 +0100
ARM: 6741/1: errata: pl310 cache sync operation may be faulty
The effect of cache sync operation is to drain the store buffer and
wait for all internal buffers to be empty. In normal conditions, store
buffer is able to merge the normal memory writes within its 32-byte
data buffers. Due to this erratum present in r3p0, the effect of cache
sync operation on the store buffer still remains when the operation
completes. This means that the store buffer is always asked to drain
and this prevents it from merging any further writes.
This can severely affect performance on the write traffic esp. on
Normal memory NC one.
The proposed workaround is to replace the normal offset of cache sync
operation(0x730) by another offset targeting an unmapped PL310
register 0x740.
Signed-off-by: srinidhi kasagar <[email protected]>
Acked-by: Linus Walleij <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Signed-off-by: Russell King <[email protected]>
[1]:
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0246d/Beibhhee.html
--
bye,
p.
>From 64d6265cbdd6bd1fa0f3809c1da4c743d9a60018 Mon Sep 17 00:00:00 2001
From: Paolo Pisati <[email protected]>
Date: Thu, 5 May 2011 23:59:37 +0200
Subject: [PATCH] OMAP4: pandaboard: Select ERRATA_753970
Signed-off-by: Paolo Pisati <[email protected]>
---
arch/arm/mach-omap2/Kconfig | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mach-omap2/Kconfig b/arch/arm/mach-omap2/Kconfig
index b997a35..525d5e1 100644
--- a/arch/arm/mach-omap2/Kconfig
+++ b/arch/arm/mach-omap2/Kconfig
@@ -321,6 +321,7 @@ config MACH_OMAP4_PANDA
select OMAP_PACKAGE_CBL
select OMAP_PACKAGE_CBS
select REGULATOR_FIXED_VOLTAGE
+ select ARM_ERRATA_753970
config OMAP3_EMU
bool "OMAP3 debugging peripherals"
--
1.7.1
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