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Patch "ARM: dts: realview: Fix PBX-A9 cache description" has been added to the 4.7-stable tree

PATCH [email protected] 1 participant 1 message Aug 18, 2016

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This is a note to let you know that I've just added the patch titled

ARM: dts: realview: Fix PBX-A9 cache description

to the 4.7-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-dts-realview-fix-pbx-a9-cache-description.patch
and it can be found in the queue-4.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From a20303725ec31ea0fcf498f1885b1d4245a4ee56 Mon Sep 17 00:00:00 2001

From: Robin Murphy <[email protected]>
Date: Wed, 10 Aug 2016 14:02:17 +0200
Subject: ARM: dts: realview: Fix PBX-A9 cache description

From: Robin Murphy <[email protected]>

commit a20303725ec31ea0fcf498f1885b1d4245a4ee56 upstream.

Clearly QEMU is very permissive in how its PL310 model may be set up, but the real hardware turns out to be far more particular about things actually being correct. Fix up the DT description so that the real thing actually boots:

- The arm,data-latency and arm,tag-latency properties need 3 cells to be valid, otherwise we end up retaining the default 8-cycle latencies which leads pretty quickly to lockup.
- The arm,dirty-latency property is only relevant to L210/L220, so get rid of it.
- The cache geometry override also leads to lockup and/or general misbehaviour. Irritatingly, the manual doesn't state the actual PL310 configuration, but based on the boardfile code and poking registers from the Boot Monitor, it would seem to be 8 sets of 16KB ways.

With that, we can successfully boot to enjoy the fun of mismatched FPUs...

---
 arch/arm/boot/dts/arm-realview-pbx-a9.dts |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)
arch/arm/boot/dts/arm-realview-pbx-a9.dts +4 -5
@@ -70,13 +70,12 @@
 		 * associativity as these may be erroneously set
 		 * up by boot loader(s).
 		 */
-		cache-size = <1048576>; // 1MB
-		cache-sets = <4096>;
+		cache-size = <131072>; // 128KB
+		cache-sets = <512>;
 		cache-line-size = <32>;
 		arm,parity-disable;
-		arm,tag-latency = <1>;
-		arm,data-latency = <1 1>;
-		arm,dirty-latency = <1>;
+		arm,tag-latency = <1 1 1>;
+		arm,data-latency = <1 1 1>;
 	};
 
 	scu: scu@1f000000 {

Patches currently in stable-queue which might be from [email protected] are

queue-4.7/iommu-io-pgtable-arm-fix-iova_to_phys-for-block-entries.patch queue-4.7/arm-dts-realview-fix-pbx-a9-cache-description.patch