Re: [RFC PATCH 0/4] Stop losing firmware-set DMA masks
From: Atish Patra
Date: Tue Jul 10 2018 - 14:21:14 EST
On 7/10/18 11:01 AM, Christoph Hellwig wrote:
These patches attempt to deal with this in the simplest way possible by
generalising the specific quirk for 32-bit bridges into an arbitrary
mask which can then also be plumbed into the firmware code. In the
interest of being minimally invasive, I've only included a point fix
for the IOMMU issue as seen on arm64 - there may be further tweaks
needed in DMA ops to catch all possible incarnations of this problem,
but this initial RFC is mostly about the impact beyond the dma-mapping
subsystem itself.
Thanks, this looks very nice to me.
In fact it probably solves the RISC-V/Xiling problem as well if we can
just add the dma-ranges property to the device tree for the affected
systems. Palmer, do you know how easily the DT could be updated for
that case?
Hi Chris,
I have a PR in riscv-pk that can modify the DT in bbl easily. In fact,
that's how I added the timer node for the interrupt patch.
https://github.com/riscv/riscv-pk/pull/112
Obviously, the best approach would be to update the firmware but that
may be time consuming sometime.
Regards,
Atish
Robin.
[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-May/580804.html
[2] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-December/474443.html
Robin Murphy (4):
dma-mapping: Generalise dma_32bit_limit flag
ACPI/IORT: Set bus DMA mask as appropriate
of/device: Set bus DMA mask as appropriate
iommu/dma: Respect bus DMA limit for IOVAs
arch/x86/kernel/pci-dma.c | 2 +-
drivers/acpi/arm64/iort.c | 1 +
drivers/iommu/dma-iommu.c | 3 +++
drivers/of/device.c | 1 +
include/linux/device.h | 6 +++---
kernel/dma/direct.c | 2 +-
6 files changed, 10 insertions(+), 5 deletions(-)
--
2.17.1.dirty
---end quoted text---
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