linux/drivers/dma/Kconfig
Dan Williams 0036731c88 async_tx: kill tx_set_src and tx_set_dest methods
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>
2008-02-06 10:12:17 -07:00

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#
# DMA engine configuration
#
menuconfig DMADEVICES
bool "DMA Engine support"
depends on (PCI && X86) || ARCH_IOP32X || ARCH_IOP33X || ARCH_IOP13XX
depends on !HIGHMEM64G
help
DMA engines can do asynchronous data transfers without
involving the host CPU. Currently, this framework can be
used to offload memory copies in the network stack and
RAID operations in the MD driver.
if DMADEVICES
comment "DMA Devices"
config INTEL_IOATDMA
tristate "Intel I/OAT DMA support"
depends on PCI && X86
select DMA_ENGINE
select DCA
help
Enable support for the Intel(R) I/OAT DMA engine present
in recent Intel Xeon chipsets.
Say Y here if you have such a chipset.
If unsure, say N.
config INTEL_IOP_ADMA
tristate "Intel IOP ADMA support"
depends on ARCH_IOP32X || ARCH_IOP33X || ARCH_IOP13XX
select ASYNC_CORE
select DMA_ENGINE
help
Enable support for the Intel(R) IOP Series RAID engines.
config DMA_ENGINE
bool
comment "DMA Clients"
depends on DMA_ENGINE
config NET_DMA
bool "Network: TCP receive copy offload"
depends on DMA_ENGINE && NET
help
This enables the use of DMA engines in the network stack to
offload receive copy-to-user operations, freeing CPU cycles.
Since this is the main user of the DMA engine, it should be enabled;
say Y here.
endif