linux.git/kernel/dma/Makefile, branch v6.18.21

dma-mapping: clearly mark DMA ops as an architecture feature

2024-09-04T04:08:51+00:00

DMA ops are a helper for architectures and not for drivers to override
the DMA implementation.

Unfortunately driver authors keep ignoring this.  Make the fact more
clear by renaming the symbol to ARCH_HAS_DMA_OPS and having the two drivers
overriding their dma_ops depend on that.  These drivers should probably be
marked broken, but we can give them a bit of a grace period for that.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Thomas Gleixner 
Acked-by: Sakari Ailus  # for IPU6
Acked-by: Robin Murphy

dma-mapping: direct calls for dma-iommu

2024-08-22T04:18:11+00:00

Directly call into dma-iommu just like we have been doing for dma-direct
for a while.  This avoids the indirect call overhead for IOMMU ops and
removes the need to have DMA ops entirely for many common configurations.

Signed-off-by: Leon Romanovsky 
Signed-off-by: Leon Romanovsky 
Acked-by: Greg Kroah-Hartman 
Acked-by: Robin Murphy 
Signed-off-by: Christoph Hellwig

dma-mapping: remove CONFIG_DMA_REMAP

2022-03-03T11:00:57+00:00

CONFIG_DMA_REMAP is used to build a few helpers around the core
vmalloc code, and to use them in case there is a highmem page in
dma-direct, and to make dma coherent allocations be able to use
non-contiguous pages allocations for DMA allocations in the dma-iommu
layer.

Right now it needs to be explicitly selected by architectures, and
is only done so by architectures that require remapping to deal
with devices that are not DMA coherent.  Make it unconditional for
builds with CONFIG_MMU as it is very little extra code, but makes
it much more likely that large DMA allocations succeed on x86.

This fixes hot plugging a NVMe thunderbolt SSD for me, which tries
to allocate a 1MB buffer that is otherwise hard to obtain due to
memory fragmentation on a heavily used laptop.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Robin Murphy

Merge tag 'dma-mapping-5.11' of git://git.infradead.org/users/hch/dma-mapping

2020-12-22T21:19:43+00:00

Pull dma-mapping updates from Christoph Hellwig:

 - support for a partial IOMMU bypass (Alexey Kardashevskiy)

 - add a DMA API benchmark (Barry Song)

 - misc fixes (Tiezhu Yang, tangjianqiang)

* tag 'dma-mapping-5.11' of git://git.infradead.org/users/hch/dma-mapping:
  selftests/dma: add test application for DMA_MAP_BENCHMARK
  dma-mapping: add benchmark support for streaming DMA APIs
  dma-contiguous: fix a typo error in a comment
  dma-pool: no need to check return value of debugfs_create functions
  powerpc/dma: Fallback to dma_ops when persistent memory present
  dma-mapping: Allow mixing bypass and mapped DMA operation

dma-mapping: add benchmark support for streaming DMA APIs

2020-11-27T09:33:42+00:00

Nowadays, there are increasing requirements to benchmark the performance
of dma_map and dma_unmap particually while the device is attached to an
IOMMU.

This patch enables the support. Users can run specified number of threads
to do dma_map_page and dma_unmap_page on a specific NUMA node with the
specified duration. Then dma_map_benchmark will calculate the average
latency for map and unmap.

A difficulity for this benchmark is that dma_map/unmap APIs must run on
a particular device. Each device might have different backend of IOMMU or
non-IOMMU.

So we use the driver_override to bind dma_map_benchmark to a particual
device by:
For platform devices:
echo dma_map_benchmark > /sys/bus/platform/devices/xxx/driver_override
echo xxx > /sys/bus/platform/drivers/xxx/unbind
echo xxx > /sys/bus/platform/drivers/dma_map_benchmark/bind

For PCI devices:
echo dma_map_benchmark > /sys/bus/pci/devices/0000:00:01.0/driver_override
echo 0000:00:01.0 > /sys/bus/pci/drivers/xxx/unbind
echo 0000:00:01.0 > /sys/bus/pci/drivers/dma_map_benchmark/bind

Cc: Will Deacon 
Cc: Shuah Khan 
Cc: Christoph Hellwig 
Cc: Marek Szyprowski 
Cc: Robin Murphy 
Signed-off-by: Barry Song 
[hch: folded in two fixes from Colin Ian King ]
Signed-off-by: Christoph Hellwig

dma-mapping: remove dma_virt_ops

2020-11-17T19:22:07+00:00

Now that the RDMA core deals with devices that only do DMA mapping in
lower layers properly, there is no user for dma_virt_ops and it can be
removed.

Link: https://lore.kernel.org/r/20201106181941.1878556-11-hch@lst.de
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jason Gunthorpe

dma-mapping: move dma_common_{mmap,get_sgtable} out of mapping.c

2020-09-11T07:14:56+00:00

Add a new file that contains helpers for misc DMA ops, which is only
built when CONFIG_DMA_OPS is set.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Robin Murphy

dma-mapping: make support for dma ops optional

2020-07-19T07:29:23+00:00

Avoid the overhead of the dma ops support for tiny builds that only
use the direct mapping.

Signed-off-by: Christoph Hellwig 
Tested-by: Alexey Kardashevskiy 
Reviewed-by: Alexey Kardashevskiy

dma-remap: separate DMA atomic pools from direct remap code

2020-04-20T10:08:45+00:00

DMA atomic pools will be needed beyond only CONFIG_DMA_DIRECT_REMAP so
separate them out into their own file.

This also adds a new Kconfig option that can be subsequently used for
options, such as CONFIG_AMD_MEM_ENCRYPT, that will utilize the coherent
pools but do not have a dependency on direct remapping.

For this patch alone, there is no functional change introduced.

Reviewed-by: Christoph Hellwig 
Signed-off-by: David Rientjes 
[hch: fixup copyrights and remove unused includes]
Signed-off-by: Christoph Hellwig

dma-mapping: improve selection of dma_declare_coherent availability

2019-02-20T14:26:35+00:00

This API is primarily used through DT entries, but two architectures
and two drivers call it directly.  So instead of selecting the config
symbol for random architectures pull it in implicitly for the actual
users.  Also rename the Kconfig option to describe the feature better.

Signed-off-by: Christoph Hellwig 
Acked-by: Paul Burton  # MIPS
Acked-by: Lee Jones 
Reviewed-by: Greg Kroah-Hartman