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authorThomas Petazzoni <thomas.petazzoni@free-electrons.com>2015-01-28 12:55:45 +0100
committerAndrew Lunn <andrew@lunn.ch>2015-01-28 11:23:56 -0600
commitdcad68876c21bac709b01eda24e39d4410dc36a8 (patch)
treebed81a76c1066fd7a9f1f68b30baa7be61d570e5
parent38bdf45f4aa5cb6186d50a29e6cbbd9d486a1519 (diff)
ARM: mvebu: don't set the PL310 in I/O coherency mode when I/O coherency is disabled
Since commit f2c3c67f00 (merge commit that adds commit "ARM: mvebu: completely disable hardware I/O coherency"), we disable I/O coherency on Armada EBU platforms. However, we continue to initialize the coherency fabric, because this coherency fabric is needed on Armada XP for inter-CPU coherency. Unfortunately, due to this, we also continued to execute the coherency fabric initialization code for Armada 375/38x, which switched the PL310 into I/O coherent mode. This has the effect of disabling the outer cache sync operation: this is needed when I/O coherency is enabled to work around a PCIe/L2 deadlock. But obviously, when I/O coherency is disabled, having the outer cache sync operation is crucial. Therefore, this commit fixes the armada_375_380_coherency_init() so that the PL310 is switched to I/O coherent mode only if I/O coherency is enabled. Without this fix, all devices using DMA are broken on Armada 375/38x. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com> Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> Signed-off-by: Andrew Lunn <andrew@lunn.ch> Cc: <stable@vger.kernel.org> # v3.8+
-rw-r--r--arch/arm/mach-mvebu/coherency.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/arm/mach-mvebu/coherency.c b/arch/arm/mach-mvebu/coherency.c
index caa21e9b8cd9..ccef8806bb58 100644
--- a/arch/arm/mach-mvebu/coherency.c
+++ b/arch/arm/mach-mvebu/coherency.c
@@ -190,6 +190,13 @@ static void __init armada_375_380_coherency_init(struct device_node *np)
arch_ioremap_caller = armada_pcie_wa_ioremap_caller;
/*
+ * We should switch the PL310 to I/O coherency mode only if
+ * I/O coherency is actually enabled.
+ */
+ if (!coherency_available())
+ return;
+
+ /*
* Add the PL310 property "arm,io-coherent". This makes sure the
* outer sync operation is not used, which allows to
* workaround the system erratum that causes deadlocks when