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Some platforms do have DMA, but DMA there is always direct and coherent. Currently, even on such platforms DMA sync operations are compiled and called. Add a new hidden Kconfig symbol, DMA_NEED_SYNC, and set it only when either sync operations are needed or there is DMA ops or swiotlb or DMA debug is enabled. Compile global dma_sync_*() and dma_need_sync() only when it's set, otherwise provide empty inline stubs. The change allows for future optimizations of DMA sync calls depending on runtime conditions. Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
289 lines
7.5 KiB
Plaintext
289 lines
7.5 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
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config NO_DMA
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bool
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config HAS_DMA
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bool
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depends on !NO_DMA
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default y
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config DMA_OPS
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depends on HAS_DMA
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bool
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#
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# IOMMU drivers that can bypass the IOMMU code and optionally use the direct
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# mapping fast path should select this option and set the dma_ops_bypass
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# flag in struct device where applicable
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#
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config DMA_OPS_BYPASS
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bool
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# Lets platform IOMMU driver choose between bypass and IOMMU
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config ARCH_HAS_DMA_MAP_DIRECT
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bool
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config NEED_SG_DMA_FLAGS
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bool
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config NEED_SG_DMA_LENGTH
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bool
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config NEED_DMA_MAP_STATE
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bool
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config ARCH_DMA_ADDR_T_64BIT
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def_bool 64BIT || PHYS_ADDR_T_64BIT
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config ARCH_HAS_DMA_SET_MASK
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bool
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#
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# Select this option if the architecture needs special handling for
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# DMA_ATTR_WRITE_COMBINE. Normally the "uncached" mapping should be what
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# people think of when saying write combine, so very few platforms should
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# need to enable this.
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#
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config ARCH_HAS_DMA_WRITE_COMBINE
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bool
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#
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# Select if the architectures provides the arch_dma_mark_clean hook
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#
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config ARCH_HAS_DMA_MARK_CLEAN
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bool
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config DMA_DECLARE_COHERENT
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bool
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config ARCH_HAS_SETUP_DMA_OPS
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bool
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config ARCH_HAS_TEARDOWN_DMA_OPS
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bool
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config ARCH_HAS_SYNC_DMA_FOR_DEVICE
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bool
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config ARCH_HAS_SYNC_DMA_FOR_CPU
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bool
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select NEED_DMA_MAP_STATE
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config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
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bool
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config ARCH_HAS_DMA_PREP_COHERENT
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bool
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config ARCH_HAS_FORCE_DMA_UNENCRYPTED
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bool
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#
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# Select this option if the architecture assumes DMA devices are coherent
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# by default.
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#
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config ARCH_DMA_DEFAULT_COHERENT
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bool
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config SWIOTLB
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bool
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select NEED_DMA_MAP_STATE
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config SWIOTLB_DYNAMIC
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bool "Dynamic allocation of DMA bounce buffers"
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default n
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depends on SWIOTLB
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help
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This enables dynamic resizing of the software IO TLB. The kernel
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starts with one memory pool at boot and it will allocate additional
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pools as needed. To reduce run-time kernel memory requirements, you
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may have to specify a smaller size of the initial pool using
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"swiotlb=" on the kernel command line.
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If unsure, say N.
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config DMA_BOUNCE_UNALIGNED_KMALLOC
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bool
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depends on SWIOTLB
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config DMA_NEED_SYNC
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def_bool ARCH_HAS_SYNC_DMA_FOR_DEVICE || ARCH_HAS_SYNC_DMA_FOR_CPU || \
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ARCH_HAS_SYNC_DMA_FOR_CPU_ALL || DMA_API_DEBUG || DMA_OPS || \
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SWIOTLB
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config DMA_RESTRICTED_POOL
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bool "DMA Restricted Pool"
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depends on OF && OF_RESERVED_MEM && SWIOTLB
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help
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This enables support for restricted DMA pools which provide a level of
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DMA memory protection on systems with limited hardware protection
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capabilities, such as those lacking an IOMMU.
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For more information see
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<Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt>
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and <kernel/dma/swiotlb.c>.
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If unsure, say "n".
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#
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# Should be selected if we can mmap non-coherent mappings to userspace.
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# The only thing that is really required is a way to set an uncached bit
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# in the pagetables
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#
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config DMA_NONCOHERENT_MMAP
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default y if !MMU
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bool
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config DMA_COHERENT_POOL
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select GENERIC_ALLOCATOR
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bool
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config DMA_GLOBAL_POOL
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select DMA_DECLARE_COHERENT
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depends on !ARCH_HAS_DMA_SET_UNCACHED
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depends on !DMA_DIRECT_REMAP
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bool
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config DMA_DIRECT_REMAP
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bool
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select DMA_COHERENT_POOL
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select DMA_NONCOHERENT_MMAP
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#
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# Fallback to arch code for DMA allocations. This should eventually go away.
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#
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config ARCH_HAS_DMA_ALLOC
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depends on !ARCH_HAS_DMA_SET_UNCACHED
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depends on !DMA_DIRECT_REMAP
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depends on !DMA_GLOBAL_POOL
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bool
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config DMA_CMA
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bool "DMA Contiguous Memory Allocator"
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depends on HAVE_DMA_CONTIGUOUS && CMA
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help
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This enables the Contiguous Memory Allocator which allows drivers
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to allocate big physically-contiguous blocks of memory for use with
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hardware components that do not support I/O map nor scatter-gather.
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You can disable CMA by specifying "cma=0" on the kernel's command
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line.
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For more information see <kernel/dma/contiguous.c>.
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If unsure, say "n".
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if DMA_CMA
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config DMA_NUMA_CMA
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bool "Enable separate DMA Contiguous Memory Area for NUMA Node"
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depends on NUMA
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help
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Enable this option to get numa CMA areas so that NUMA devices
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can get local memory by DMA coherent APIs.
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You can set the size of pernuma CMA by specifying "cma_pernuma=size"
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or set the node id and its size of CMA by specifying "numa_cma=
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<node>:size[,<node>:size]" on the kernel's command line.
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comment "Default contiguous memory area size:"
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config CMA_SIZE_MBYTES
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int "Size in Mega Bytes"
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depends on !CMA_SIZE_SEL_PERCENTAGE
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default 0 if X86
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default 16
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help
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Defines the size (in MiB) of the default memory area for Contiguous
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Memory Allocator. If the size of 0 is selected, CMA is disabled by
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default, but it can be enabled by passing cma=size[MG] to the kernel.
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config CMA_SIZE_PERCENTAGE
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int "Percentage of total memory"
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depends on !CMA_SIZE_SEL_MBYTES
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default 0 if X86
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default 10
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help
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Defines the size of the default memory area for Contiguous Memory
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Allocator as a percentage of the total memory in the system.
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If 0 percent is selected, CMA is disabled by default, but it can be
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enabled by passing cma=size[MG] to the kernel.
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choice
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prompt "Selected region size"
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default CMA_SIZE_SEL_MBYTES
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config CMA_SIZE_SEL_MBYTES
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bool "Use mega bytes value only"
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config CMA_SIZE_SEL_PERCENTAGE
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bool "Use percentage value only"
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config CMA_SIZE_SEL_MIN
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bool "Use lower value (minimum)"
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config CMA_SIZE_SEL_MAX
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bool "Use higher value (maximum)"
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endchoice
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config CMA_ALIGNMENT
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int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
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range 2 12
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default 8
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help
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DMA mapping framework by default aligns all buffers to the smallest
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PAGE_SIZE order which is greater than or equal to the requested buffer
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size. This works well for buffers up to a few hundreds kilobytes, but
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for larger buffers it just a memory waste. With this parameter you can
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specify the maximum PAGE_SIZE order for contiguous buffers. Larger
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buffers will be aligned only to this specified order. The order is
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expressed as a power of two multiplied by the PAGE_SIZE.
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For example, if your system defaults to 4KiB pages, the order value
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of 8 means that the buffers will be aligned up to 1MiB only.
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If unsure, leave the default value "8".
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endif
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config DMA_API_DEBUG
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bool "Enable debugging of DMA-API usage"
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select NEED_DMA_MAP_STATE
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help
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Enable this option to debug the use of the DMA API by device drivers.
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With this option you will be able to detect common bugs in device
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drivers like double-freeing of DMA mappings or freeing mappings that
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were never allocated.
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This option causes a performance degradation. Use only if you want to
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debug device drivers and dma interactions.
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If unsure, say N.
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config DMA_API_DEBUG_SG
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bool "Debug DMA scatter-gather usage"
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default y
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depends on DMA_API_DEBUG
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help
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Perform extra checking that callers of dma_map_sg() have respected the
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appropriate segment length/boundary limits for the given device when
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preparing DMA scatterlists.
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This is particularly likely to have been overlooked in cases where the
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dma_map_sg() API is used for general bulk mapping of pages rather than
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preparing literal scatter-gather descriptors, where there is a risk of
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unexpected behaviour from DMA API implementations if the scatterlist
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is technically out-of-spec.
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If unsure, say N.
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config DMA_MAP_BENCHMARK
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bool "Enable benchmarking of streaming DMA mapping"
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depends on DEBUG_FS
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help
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Provides /sys/kernel/debug/dma_map_benchmark that helps with testing
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performance of dma_(un)map_page.
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See tools/testing/selftests/dma/dma_map_benchmark.c
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