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ARM: mvebu: don't set the PL310 in I/O coherency mode when I/O coherency is disabled

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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+
This commit is contained in:
Thomas Petazzoni 2015-01-28 12:55:45 +01:00 • committed by Andrew Lunn
parent 38bdf45f4a
commit dcad68876c
1 changed files with 7 additions and 0 deletions
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7
arch/arm/mach-mvebu/coherency.c
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@ -189,6 +189,13 @@ static void __init armada_375_380_coherency_init(struct device_node *np)
coherency_cpu_base = of_iomap(np, 0);
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