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0036731c88
The tx_set_src and tx_set_dest methods were originally implemented to allow an array of addresses to be passed down from async_xor to the dmaengine driver while minimizing stack overhead. Removing these methods allows drivers to have all transaction parameters available at 'prep' time, saves two function pointers in struct dma_async_tx_descriptor, and reduces the number of indirect branches.. A consequence of moving this data to the 'prep' routine is that multi-source routines like async_xor need temporary storage to convert an array of linear addresses into an array of dma addresses. In order to keep the same stack footprint of the previous implementation the input array is reused as storage for the dma addresses. This requires that sizeof(dma_addr_t) be less than or equal to sizeof(void *). As a consequence CONFIG_DMADEVICES now depends on !CONFIG_HIGHMEM64G. It also requires that drivers be able to make descriptor resources available when the 'prep' routine is polled. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Shannon Nelson <shannon.nelson@intel.com>
55 lines
1.3 KiB
Text
55 lines
1.3 KiB
Text
#
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# DMA engine configuration
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#
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menuconfig DMADEVICES
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bool "DMA Engine support"
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depends on (PCI && X86) || ARCH_IOP32X || ARCH_IOP33X || ARCH_IOP13XX
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depends on !HIGHMEM64G
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help
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DMA engines can do asynchronous data transfers without
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involving the host CPU. Currently, this framework can be
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used to offload memory copies in the network stack and
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RAID operations in the MD driver.
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if DMADEVICES
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comment "DMA Devices"
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config INTEL_IOATDMA
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tristate "Intel I/OAT DMA support"
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depends on PCI && X86
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select DMA_ENGINE
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select DCA
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help
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Enable support for the Intel(R) I/OAT DMA engine present
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in recent Intel Xeon chipsets.
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Say Y here if you have such a chipset.
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If unsure, say N.
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config INTEL_IOP_ADMA
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tristate "Intel IOP ADMA support"
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depends on ARCH_IOP32X || ARCH_IOP33X || ARCH_IOP13XX
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select ASYNC_CORE
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select DMA_ENGINE
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help
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Enable support for the Intel(R) IOP Series RAID engines.
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config DMA_ENGINE
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bool
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comment "DMA Clients"
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depends on DMA_ENGINE
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config NET_DMA
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bool "Network: TCP receive copy offload"
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depends on DMA_ENGINE && NET
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help
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This enables the use of DMA engines in the network stack to
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offload receive copy-to-user operations, freeing CPU cycles.
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Since this is the main user of the DMA engine, it should be enabled;
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say Y here.
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endif
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