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f0d1b0b30d
This facility provides three entry points:
ilog2() Log base 2 of unsigned long
ilog2_u32() Log base 2 of u32
ilog2_u64() Log base 2 of u64
These facilities can either be used inside functions on dynamic data:
int do_something(long q)
{
...;
y = ilog2(x)
...;
}
Or can be used to statically initialise global variables with constant values:
unsigned n = ilog2(27);
When performing static initialisation, the compiler will report "error:
initializer element is not constant" if asked to take a log of zero or of
something not reducible to a constant. They treat negative numbers as
unsigned.
When not dealing with a constant, they fall back to using fls() which permits
them to use arch-specific log calculation instructions - such as BSR on
x86/x86_64 or SCAN on FRV - if available.
[akpm@osdl.org: MMC fix]
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Howells <dhowells@redhat.com>
Cc: Wojtek Kaniewski <wojtekka@toxygen.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
201 lines
3.7 KiB
Plaintext
201 lines
3.7 KiB
Plaintext
#
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# For a description of the syntax of this configuration file,
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# see the Configure script.
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#
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mainmenu "Linux/CRIS Kernel Configuration"
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config MMU
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bool
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default y
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config RWSEM_GENERIC_SPINLOCK
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bool
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default y
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config RWSEM_XCHGADD_ALGORITHM
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bool
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config ARCH_HAS_ILOG2_U32
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bool
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default n
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config ARCH_HAS_ILOG2_U64
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bool
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default n
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config GENERIC_FIND_NEXT_BIT
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bool
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default y
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config GENERIC_HWEIGHT
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bool
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default y
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config GENERIC_CALIBRATE_DELAY
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bool
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default y
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config IRQ_PER_CPU
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bool
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default y
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config CRIS
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bool
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default y
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source "init/Kconfig"
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menu "General setup"
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source "fs/Kconfig.binfmt"
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config ETRAX_CMDLINE
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string "Kernel command line"
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default "root=/dev/mtdblock3"
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help
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Pass additional commands to the kernel.
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config ETRAX_WATCHDOG
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bool "Enable ETRAX watchdog"
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help
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Enable the built-in watchdog timer support on ETRAX based embedded
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network computers.
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config ETRAX_WATCHDOG_NICE_DOGGY
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bool "Disable watchdog during Oops printouts"
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depends on ETRAX_WATCHDOG
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help
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By enabling this you make sure that the watchdog does not bite while
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printing oopses. Recommended for development systems but not for
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production releases.
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config ETRAX_FAST_TIMER
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bool "Enable ETRAX fast timer API"
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help
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This options enables the API to a fast timer implementation using
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timer1 to get sub jiffie resolution timers (primarily one-shot
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timers).
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This is needed if CONFIG_ETRAX_SERIAL_FAST_TIMER is enabled.
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config PREEMPT
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bool "Preemptible Kernel"
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help
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This option reduces the latency of the kernel when reacting to
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real-time or interactive events by allowing a low priority process to
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be preempted even if it is in kernel mode executing a system call.
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This allows applications to run more reliably even when the system is
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under load.
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Say Y here if you are building a kernel for a desktop, embedded
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or real-time system. Say N if you are unsure.
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source mm/Kconfig
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endmenu
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menu "Hardware setup"
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choice
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prompt "Processor type"
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default ETRAX100LX
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config ETRAX100LX
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bool "ETRAX-100LX-v1"
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help
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Support version 1 of the ETRAX 100LX.
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config ETRAX100LX_V2
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bool "ETRAX-100LX-v2"
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help
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Support version 2 of the ETRAX 100LX.
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config SVINTO_SIM
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bool "ETRAX-100LX-for-xsim-simulator"
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help
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Support the xsim ETRAX Simulator.
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endchoice
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config ETRAX_ARCH_V10
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bool
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default y if ETRAX100LX || ETRAX100LX_V2
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default n if !(ETRAX100LX || ETRAX100LX_V2)
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config ETRAX_DRAM_SIZE
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int "DRAM size (dec, in MB)"
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default "8"
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help
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Size of DRAM (decimal in MB) typically 2, 8 or 16.
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config ETRAX_FLASH_BUSWIDTH
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int "Buswidth of flash in bytes"
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default "2"
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help
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Width in bytes of the Flash bus (1, 2 or 4). Is usually 2.
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source arch/cris/arch-v10/Kconfig
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endmenu
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source "net/Kconfig"
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# bring in ETRAX built-in drivers
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menu "Drivers for built-in interfaces"
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source arch/cris/arch-v10/drivers/Kconfig
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endmenu
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source "drivers/base/Kconfig"
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# standard linux drivers
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source "drivers/mtd/Kconfig"
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source "drivers/parport/Kconfig"
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source "drivers/pnp/Kconfig"
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source "drivers/block/Kconfig"
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source "drivers/md/Kconfig"
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source "drivers/ide/Kconfig"
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source "drivers/scsi/Kconfig"
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source "drivers/ieee1394/Kconfig"
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source "drivers/message/i2o/Kconfig"
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source "drivers/net/Kconfig"
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source "drivers/isdn/Kconfig"
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source "drivers/telephony/Kconfig"
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source "drivers/cdrom/Kconfig"
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#
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# input before char - char/joystick depends on it. As does USB.
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#
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source "drivers/input/Kconfig"
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source "drivers/char/Kconfig"
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#source drivers/misc/Config.in
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source "drivers/media/Kconfig"
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source "fs/Kconfig"
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source "sound/Kconfig"
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source "drivers/usb/Kconfig"
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source "arch/cris/Kconfig.debug"
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source "security/Kconfig"
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source "crypto/Kconfig"
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source "lib/Kconfig"
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