| From dcad68876c21bac709b01eda24e39d4410dc36a8 Mon Sep 17 00:00:00 2001 |
| From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> |
| Date: Wed, 28 Jan 2015 12:55:45 +0100 |
| Subject: ARM: mvebu: don't set the PL310 in I/O coherency mode when I/O coherency is disabled |
| |
| From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> |
| |
| commit dcad68876c21bac709b01eda24e39d4410dc36a8 upstream. |
| |
| 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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/arm/mach-mvebu/coherency.c | 7 +++++++ |
| 1 file changed, 7 insertions(+) |
| |
| --- a/arch/arm/mach-mvebu/coherency.c |
| +++ b/arch/arm/mach-mvebu/coherency.c |
| @@ -342,6 +342,13 @@ static void __init armada_375_380_cohere |
| 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 |