Hello,
This is the last missing piece to let us efficiently use large DMA
buffers on systems with lots of memory, which have support for himem
enabled. The first patch adds support for CMA regions placed in high
memory zones, the second one also enables allocations of individual
pages from high memory zone for IOMMU-mapped devices. Those two changes
let us to significantly save low memory for other tasks.
Best regards
Marek Szyprowski
Samsung Poland R&D Center
Patch summary:
Marek Szyprowski (2):
ARM: dma-mapping: add support for CMA regions placed in highmem zone
ARM: dma-mapping: use himem for DMA buffers for IOMMU-mapped devices
arch/arm/mm/dma-mapping.c | 70 +++++++++++++++++++++++++++++++++------------
1 file changed, 52 insertions(+), 18 deletions(-)
--
1.7.9.5
So I'm resending the patch series for reservations. This is identical to my git
tree at
http://cgit.freedesktop.org/~mlankhorst/linux/
Some changes have been made since my last version. Most notably is the use of
mutexes now instead of creating my own lock primitive, that would end up being
duplicate anyway.
The git tree also has a version of i915 and radeon working together like that.
It's probably a bit hacky, but it works on my macbook pro 8.2. :)
I haven't had any reply on the mutex extensions when I sent them out separately,
so I'm including it in the series.
The idea is that for lockdep purposes, the seqno is tied to a locking a class.
This locking class it not exclusive, but as can be seen from the last patch in
the series, it catches all violations we care about.
Hi everybody,
Would anyone be interested in meeting at the FOSDEM to discuss the Common
Display Framework ? There will be a CDF meeting at the ELC at the end of
February, the FOSDEM would be a good venue for European developers.
--
Regards,
Laurent Pinchart
Hi all,
I've just confirmed the schedule for ELC (
http://events.linuxfoundation.org/events/embedded-linux-conference/schedule),
and we're on for Thursday at 4pm. I requested 2 slots to give us some
flexibility (that's the "Part I & Part II" on the schedule).
Whether you are attending the rest of ELC or not, if you care about CDF,
please come by.
cheers,
Jesse
Adding a new dma attribute which can be used by the
platform drivers to avoid creating iommu mappings.
In some cases the buffers are allocated by display
controller driver using dma alloc apis but are not
used for scanout. Though the buffers are allocated
by display controller but are only used for sharing
among different devices.
With this attribute the platform drivers can choose
not to create iommu mapping at the time of buffer
allocation and only create the mapping when they
access this buffer.
Change-Id: I2178b3756170982d814e085ca62474d07b616a21
Signed-off-by: Abhinav Kochhar <abhinav.k(a)samsung.com>
---
arch/arm/mm/dma-mapping.c | 8 +++++---
include/linux/dma-attrs.h | 1 +
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index c0f0f43..e73003c 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1279,9 +1279,11 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
if (!pages)
return NULL;
- *handle = __iommu_create_mapping(dev, pages, size);
- if (*handle == DMA_ERROR_CODE)
- goto err_buffer;
+ if (!dma_get_attr(DMA_ATTR_NO_IOMMU_MAPPING, attrs)) {
+ *handle = __iommu_create_mapping(dev, pages, size);
+ if (*handle == DMA_ERROR_CODE)
+ goto err_buffer;
+ }
if (dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs))
return pages;
diff --git a/include/linux/dma-attrs.h b/include/linux/dma-attrs.h
index c8e1831..1f04419 100644
--- a/include/linux/dma-attrs.h
+++ b/include/linux/dma-attrs.h
@@ -15,6 +15,7 @@ enum dma_attr {
DMA_ATTR_WEAK_ORDERING,
DMA_ATTR_WRITE_COMBINE,
DMA_ATTR_NON_CONSISTENT,
+ DMA_ATTR_NO_IOMMU_MAPPING,
DMA_ATTR_NO_KERNEL_MAPPING,
DMA_ATTR_SKIP_CPU_SYNC,
DMA_ATTR_FORCE_CONTIGUOUS,
--
1.7.8.6
Hi all,
With all of the attention that the Common Display Framework is getting, I
was wondering if it was worth having a BoF discussion at ELC next month in
San Francisco. This will be only a couple of weeks after FOSDEM, but given
the pace that things seem to be moving, that could be a great opportunity
either to have a follow-on discussion, or simply to involve a slightly
different cross-section of the community in a face-to-face discussion. If
folks could let me know that they'll be at ELC and are interested in a BoF
there, I'll look into getting it set up.
cheers,
Jesse