On 20/03/14 17:09, Arnd Bergmann wrote:
On Thursday 20 March 2014 16:04:36 Ben Dooks wrote:
On 26/02/14 20:57, Arnd Bergmann wrote:
On Wednesday 26 February 2014 12:48:17 Bjorn Helgaas wrote:
On Mon, Feb 24, 2014 at 4:00 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
Hi Magnus,
I noticed during randconfig testing that you enabled DMABOUNCE for the
pci-rcar-gen2 driver as posted in this patch https://lkml.org/lkml/2014/2/5/30
I didn't see the original post unfortunately, but I fear we have to
revert it and come up with a better solution, ...
Sounds like I should drop the following patches from my pci/host-rcar
branch for now?
PCI: rcar: Add DMABOUNCE support
PCI: rcar: Enable BOUNCE in case of HIGHMEM
PCI: rcar: Make the Kconfig dependencies more generic
Sounds good to me. The last patch is actually fine, but you'll have to
fix the context to apply it without the other two.
As a note, if we now boot a Lager with DT on 3.14-rc3 series the USB
controllers no longer work with full 2GiB RAM enabled in the device
tree.
Did it work before these patches got applied initially?
It did, but I cannot remember if we where limiting DRAM to 1GiB
or not.
Could we work around this by having 1GiB of memory defined in the
32bit memory and then add the rest of the 3GiB from the >32bit
area via LPAE? Will the kernel ever try to allocate DMA memory from
anything >32bit?
You can solve the case for dma_alloc_coherent() this way, or by
setting the mask correctly. It won't help you for dma_map_* though,
which still requires someone to add support for swiotlb or using
an IOMMU if present.
We do not have an IOMMU present at the moment. Not sure how
to go about setting a mask on a pci-probed device.
--
Ben Dooks http://www.codethink.co.uk/
Senior Engineer Codethink - Providing Genius
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