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authorThomas Petazzoni <thomas.petazzoni@free-electrons.com>2016-06-16 15:42:26 +0200
committerGregory CLEMENT <gregory.clement@free-electrons.com>2016-06-16 17:00:40 +0200
commit6a02734d420fca778554878d03017017537d92e1 (patch)
parentc5379ba8fccd99d5f99632c789f0393d84a57805 (diff)
ARM: mvebu: map PCI I/O regions strongly ordered
In order for HW I/O coherency to work on Cortex-A9 based Marvell SoCs, all MMIO registers must be mapped strongly ordered. In commit 1c8c3cf0b5239 ("ARM: 8060/1: mm: allow sub-architectures to override PCI I/O memory type") we implemented a new function, pci_ioremap_set_mem_type(), that allow sub-architecture code to override the memory type used to map PCI I/O regions. In the discussion around this patch series [1], Arnd Bergmann made the comment that maybe all PCI I/O regions should be mapped strongly-ordered, which would have made our proposal to add pci_ioremap_set_mem_type() irrelevant. So, we submitted a patch [2] that did what Arnd suggested. However, Russell in the end merged our initial proposal to add pci_ioremap_set_mem_type(), but it was never used anywhere. Further discussion with Arnd and other folks on IRC lead to the conclusion that in fact using strongly-ordered for all platforms was maybe not desirable, and therefore, using pci_ioremap_set_mem_type() was the most appropriate solution. As a consequence, this commit finally adds the pci_ioremap_set_mem_type() call in the mach-mvebu platform code, which was originally part of our initial patch series [3] and is necessary for the whole mechanism to work. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-May/256565.html [2] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-May/256755.html [3] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-May/256563.html Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm/mach-mvebu/coherency.c b/arch/arm/mach-mvebu/coherency.c
index 474abff..e80f0dd 100644
--- a/arch/arm/mach-mvebu/coherency.c
+++ b/arch/arm/mach-mvebu/coherency.c
@@ -181,6 +181,7 @@ static void __init armada_375_380_coherency_init(struct device_node *np)
coherency_cpu_base = of_iomap(np, 0);
arch_ioremap_caller = armada_wa_ioremap_caller;
+ pci_ioremap_set_mem_type(MT_UNCACHED);
* We should switch the PL310 to I/O coherency mode only if