linux/drivers/dma/Kconfig
Dan Williams 138f4c359d dmaengine, async_tx: add a "no channel switch" allocator
Channel switching is problematic for some dmaengine drivers as the
architecture precludes separating the ->prep from ->submit.  In these
cases the driver can select ASYNC_TX_DISABLE_CHANNEL_SWITCH to modify
the async_tx allocator to only return channels that support all of the
required asynchronous operations.

For example MD_RAID456=y selects support for asynchronous xor, xor
validate, pq, pq validate, and memcpy.  When
ASYNC_TX_DISABLE_CHANNEL_SWITCH=y any channel with all these
capabilities is marked DMA_ASYNC_TX allowing async_tx_find_channel() to
quickly locate compatible channels with the guarantee that dependency
chains will remain on one channel.  When
ASYNC_TX_DISABLE_CHANNEL_SWITCH=n async_tx_find_channel() may select
channels that lead to operation chains that need to cross channel
boundaries using the async_tx channel switch capability.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-09-08 17:42:51 -07:00

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#
# DMA engine configuration
#
menuconfig DMADEVICES
bool "DMA Engine support"
depends on HAS_DMA
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. This menu only presents
DMA Device drivers supported by the configured arch, it may
be empty in some cases.
if DMADEVICES
comment "DMA Devices"
config ASYNC_TX_DISABLE_CHANNEL_SWITCH
bool
config INTEL_IOATDMA
tristate "Intel I/OAT DMA support"
depends on PCI && X86
select DMA_ENGINE
select DCA
select ASYNC_TX_DISABLE_CHANNEL_SWITCH
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 DMA_ENGINE
help
Enable support for the Intel(R) IOP Series RAID engines.
config DW_DMAC
tristate "Synopsys DesignWare AHB DMA support"
depends on AVR32
select DMA_ENGINE
default y if CPU_AT32AP7000
help
Support the Synopsys DesignWare AHB DMA controller. This
can be integrated in chips such as the Atmel AT32ap7000.
config FSL_DMA
tristate "Freescale Elo and Elo Plus DMA support"
depends on FSL_SOC
select DMA_ENGINE
---help---
Enable support for the Freescale Elo and Elo Plus DMA controllers.
The Elo is the DMA controller on some 82xx and 83xx parts, and the
Elo Plus is the DMA controller on 85xx and 86xx parts.
config MV_XOR
bool "Marvell XOR engine support"
depends on PLAT_ORION
select DMA_ENGINE
---help---
Enable support for the Marvell XOR engine.
config MX3_IPU
bool "MX3x Image Processing Unit support"
depends on ARCH_MX3
select DMA_ENGINE
default y
help
If you plan to use the Image Processing unit in the i.MX3x, say
Y here. If unsure, select Y.
config MX3_IPU_IRQS
int "Number of dynamically mapped interrupts for IPU"
depends on MX3_IPU
range 2 137
default 4
help
Out of 137 interrupt sources on i.MX31 IPU only very few are used.
To avoid bloating the irq_desc[] array we allocate a sufficient
number of IRQ slots and map them dynamically to specific sources.
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
default (INTEL_IOATDMA || FSL_DMA)
help
This enables the use of DMA engines in the network stack to
offload receive copy-to-user operations, freeing CPU cycles.
Say Y here if you enabled INTEL_IOATDMA or FSL_DMA, otherwise
say N.
config ASYNC_TX_DMA
bool "Async_tx: Offload support for the async_tx api"
depends on DMA_ENGINE
help
This allows the async_tx api to take advantage of offload engines for
memcpy, memset, xor, and raid6 p+q operations. If your platform has
a dma engine that can perform raid operations and you have enabled
MD_RAID456 say Y.
If unsure, say N.
config DMATEST
tristate "DMA Test client"
depends on DMA_ENGINE
help
Simple DMA test client. Say N unless you're debugging a
DMA Device driver.
endif