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linux-next/drivers/crypto/caam/Kconfig
Kim Phillips 1a076689cd crypto: caam - disable IRQ coalescing by default
It has been observed that in zero-loss benchmarks, when a
slow traffic rate is being tested, the IRQ timer coalescing
parameter was set too high, and the ethernet controller
would start dropping packets because the job ring back half
wouldn't be executed in time before the ethernet controller
would fill its buffers, thereby significantly reducing the
zero-loss performance figures.

Empirical testing has shown that the best zero-loss performance
is achieved when IRQ coalescing is set to minimum values and/or
turned off, since apparently the job ring driver already implements
an adequately-performing general-purpose IRQ mitigation strategy
in software.

Whilst we could go with minimal count (2-8) and timing settings
(192-256), we prefer just turning h/w coalescing altogether off
to minimize setkey latency (due to split key generation), and
for consistent cross-SoC performance (the SEC vs. core clock
ratio changes).

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2012-06-27 14:42:06 +08:00

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config CRYPTO_DEV_FSL_CAAM
tristate "Freescale CAAM-Multicore driver backend"
depends on FSL_SOC
help
Enables the driver module for Freescale's Cryptographic Accelerator
and Assurance Module (CAAM), also known as the SEC version 4 (SEC4).
This module adds a job ring operation interface, and configures h/w
to operate as a DPAA component automatically, depending
on h/w feature availability.
To compile this driver as a module, choose M here: the module
will be called caam.
config CRYPTO_DEV_FSL_CAAM_RINGSIZE
int "Job Ring size"
depends on CRYPTO_DEV_FSL_CAAM
range 2 9
default "9"
help
Select size of Job Rings as a power of 2, within the
range 2-9 (ring size 4-512).
Examples:
2 => 4
3 => 8
4 => 16
5 => 32
6 => 64
7 => 128
8 => 256
9 => 512
config CRYPTO_DEV_FSL_CAAM_INTC
bool "Job Ring interrupt coalescing"
depends on CRYPTO_DEV_FSL_CAAM
default n
help
Enable the Job Ring's interrupt coalescing feature.
Note: the driver already provides adequate
interrupt coalescing in software.
config CRYPTO_DEV_FSL_CAAM_INTC_COUNT_THLD
int "Job Ring interrupt coalescing count threshold"
depends on CRYPTO_DEV_FSL_CAAM_INTC
range 1 255
default 255
help
Select number of descriptor completions to queue before
raising an interrupt, in the range 1-255. Note that a selection
of 1 functionally defeats the coalescing feature, and a selection
equal or greater than the job ring size will force timeouts.
config CRYPTO_DEV_FSL_CAAM_INTC_TIME_THLD
int "Job Ring interrupt coalescing timer threshold"
depends on CRYPTO_DEV_FSL_CAAM_INTC
range 1 65535
default 2048
help
Select number of bus clocks/64 to timeout in the case that one or
more descriptor completions are queued without reaching the count
threshold. Range is 1-65535.
config CRYPTO_DEV_FSL_CAAM_CRYPTO_API
tristate "Register algorithm implementations with the Crypto API"
depends on CRYPTO_DEV_FSL_CAAM
default y
select CRYPTO_ALGAPI
select CRYPTO_AUTHENC
help
Selecting this will offload crypto for users of the
scatterlist crypto API (such as the linux native IPSec
stack) to the SEC4 via job ring.
To compile this as a module, choose M here: the module
will be called caamalg.
config CRYPTO_DEV_FSL_CAAM_AHASH_API
tristate "Register hash algorithm implementations with Crypto API"
depends on CRYPTO_DEV_FSL_CAAM
default y
select CRYPTO_AHASH
help
Selecting this will offload ahash for users of the
scatterlist crypto API to the SEC4 via job ring.
To compile this as a module, choose M here: the module
will be called caamhash.
config CRYPTO_DEV_FSL_CAAM_RNG_API
tristate "Register caam device for hwrng API"
depends on CRYPTO_DEV_FSL_CAAM
default y
select CRYPTO_RNG
select HW_RANDOM
help
Selecting this will register the SEC4 hardware rng to
the hw_random API for suppying the kernel entropy pool.
To compile this as a module, choose M here: the module
will be called caamrng.