This is a note to let you know that I've just added the patch titled
ARM: pxa: prevent PXA270 occasional reboot freezes
to the 3.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-pxa-prevent-pxa270-occasional-reboot-freezes.patch
and it can be found in the queue-3.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ff88b4724fde18056a4c539f7327389aec0f4c2d Mon Sep 17 00:00:00 2001
From: Sergei Ianovich <ynvich@xxxxxxxxx>
Date: Tue, 10 Dec 2013 08:39:15 +0400
Subject: ARM: pxa: prevent PXA270 occasional reboot freezes
From: Sergei Ianovich <ynvich@xxxxxxxxx>
commit ff88b4724fde18056a4c539f7327389aec0f4c2d upstream.
Erratum 71 of PXA270M Processor Family Specification Update
(April 19, 2010) explains that watchdog reset time is just
8us insead of 10ms in EMTS.
If SDRAM is not reset, it causes memory bus congestion and
the device hangs. We put SDRAM in selfresh mode before watchdog
reset, removing potential freezes.
Without this patch PXA270-based ICP DAS LP-8x4x hangs after up to 40
reboots. With this patch it has successfully rebooted 500 times.
Signed-off-by: Sergei Ianovich <ynvich@xxxxxxxxx>
Tested-by: Marek Vasut <marex@xxxxxxx>
Signed-off-by: Haojian Zhuang <haojian.zhuang@xxxxxxxxx>
Signed-off-by: Olof Johansson <olof@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/mach-pxa/reset.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/arch/arm/mach-pxa/reset.c
+++ b/arch/arm/mach-pxa/reset.c
@@ -13,6 +13,7 @@
#include <mach/regs-ost.h>
#include <mach/reset.h>
+#include <mach/smemc.h>
unsigned int reset_status;
EXPORT_SYMBOL(reset_status);
@@ -81,6 +82,12 @@ static void do_hw_reset(void)
writel_relaxed(OSSR_M3, OSSR);
/* ... in 100 ms */
writel_relaxed(readl_relaxed(OSCR) + 368640, OSMR3);
+ /*
+ * SDRAM hangs on watchdog reset on Marvell PXA270 (erratum 71)
+ * we put SDRAM into self-refresh to prevent that
+ */
+ while (1)
+ writel_relaxed(MDREFR_SLFRSH, MDREFR);
}
void pxa_restart(enum reboot_mode mode, const char *cmd)
@@ -104,4 +111,3 @@ void pxa_restart(enum reboot_mode mode,
break;
}
}
-
Patches currently in stable-queue which might be from ynvich@xxxxxxxxx are
queue-3.12/arm-pxa-prevent-pxa270-occasional-reboot-freezes.patch
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