linux_kernel/arch/xtensa/Kconfig

config ZONE_DMA
	def_bool y

config XTENSA
	def_bool y
	select ARCH_WANT_FRAME_POINTERS
	select HAVE_IDE
	select GENERIC_ATOMIC64
	select GENERIC_CLOCKEVENTS
	select VIRT_TO_BUS
	select GENERIC_IRQ_SHOW
	select GENERIC_SCHED_CLOCK
	select MODULES_USE_ELF_RELA
	select GENERIC_PCI_IOMAP
	select ARCH_WANT_IPC_PARSE_VERSION
	select ARCH_WANT_OPTIONAL_GPIOLIB
	select BUILDTIME_EXTABLE_SORT
	select CLONE_BACKWARDS
	select IRQ_DOMAIN
	select HAVE_OPROFILE
	select HAVE_FUNCTION_TRACER
	select HAVE_IRQ_TIME_ACCOUNTING
	select HAVE_PERF_EVENTS
	select COMMON_CLK
	help
	  Xtensa processors are 32-bit RISC machines designed by Tensilica
	  primarily for embedded systems.  These processors are both
	  configurable and extensible.  The Linux port to the Xtensa
	  architecture supports all processor configurations and extensions,
	  with reasonable minimum requirements.  The Xtensa Linux project has
	  a home page at <http://www.linux-xtensa.org/>.

config RWSEM_XCHGADD_ALGORITHM
	def_bool y

config GENERIC_HWEIGHT
	def_bool y

config ARCH_HAS_ILOG2_U32
	def_bool n

config ARCH_HAS_ILOG2_U64
	def_bool n

config NO_IOPORT_MAP
	def_bool n

config HZ
	int
	default 100

source "init/Kconfig"
source "kernel/Kconfig.freezer"

config LOCKDEP_SUPPORT
	def_bool y

config STACKTRACE_SUPPORT
	def_bool y

config TRACE_IRQFLAGS_SUPPORT
	def_bool y

config MMU
	def_bool n

config VARIANT_IRQ_SWITCH
	def_bool n

config HAVE_XTENSA_GPIO32
	def_bool n

config MAY_HAVE_SMP
	def_bool n

menu "Processor type and features"

choice
	prompt "Xtensa Processor Configuration"
	default XTENSA_VARIANT_FSF

config XTENSA_VARIANT_FSF
	bool "fsf - default (not generic) configuration"
	select MMU

config XTENSA_VARIANT_DC232B
	bool "dc232b - Diamond 232L Standard Core Rev.B (LE)"
	select MMU
	select HAVE_XTENSA_GPIO32
	help
	  This variant refers to Tensilica's Diamond 232L Standard core Rev.B (LE).

config XTENSA_VARIANT_DC233C
	bool "dc233c - Diamond 233L Standard Core Rev.C (LE)"
	select MMU
	select HAVE_XTENSA_GPIO32
	help
	  This variant refers to Tensilica's Diamond 233L Standard core Rev.C (LE).

config XTENSA_VARIANT_S6000
	bool "s6000 - Stretch software configurable processor"
	select VARIANT_IRQ_SWITCH
	select ARCH_REQUIRE_GPIOLIB
	select XTENSA_CALIBRATE_CCOUNT
endchoice

config XTENSA_UNALIGNED_USER
	bool "Unaligned memory access in use space"
	help
	  The Xtensa architecture currently does not handle unaligned
	  memory accesses in hardware but through an exception handler.
	  Per default, unaligned memory accesses are disabled in user space.

	  Say Y here to enable unaligned memory access in user space.

source "kernel/Kconfig.preempt"

config HAVE_SMP
	bool "System Supports SMP (MX)"
	depends on MAY_HAVE_SMP
	select XTENSA_MX
	help
	  This option is use to indicate that the system-on-a-chip (SOC)
	  supports Multiprocessing. Multiprocessor support implemented above
	  the CPU core definition and currently needs to be selected manually.

	  Multiprocessor support in implemented with external cache and
	  interrupt controlers.

	  The MX interrupt distributer adds Interprocessor Interrupts
	  and causes the IRQ numbers to be increased by 4 for devices
	  like the open cores ethernet driver and the serial interface.

	  You still have to select "Enable SMP" to enable SMP on this SOC.

config SMP
	bool "Enable Symmetric multi-processing support"
	depends on HAVE_SMP
	select GENERIC_SMP_IDLE_THREAD
	help
	  Enabled SMP Software; allows more than one CPU/CORE
	  to be activated during startup.

config NR_CPUS
	depends on SMP
	int "Maximum number of CPUs (2-32)"
	range 2 32
	default "4"

config HOTPLUG_CPU
	bool "Enable CPU hotplug support"
	depends on SMP
	help
	  Say Y here to allow turning CPUs off and on. CPUs can be
	  controlled through /sys/devices/system/cpu.

	  Say N if you want to disable CPU hotplug.

config MATH_EMULATION
	bool "Math emulation"
	help
	Can we use information of configuration file?

config INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
	bool "Initialize Xtensa MMU inside the Linux kernel code"
	default y
	help
	  Earlier version initialized the MMU in the exception vector
	  before jumping to _startup in head.S and had an advantage that
	  it was possible to place a software breakpoint at 'reset' and
	  then enter your normal kernel breakpoints once the MMU was mapped
	  to the kernel mappings (0XC0000000).

	  This unfortunately doesn't work for U-Boot and likley also wont
	  work for using KEXEC to have a hot kernel ready for doing a
	  KDUMP.

	  So now the MMU is initialized in head.S but it's necessary to
	  use hardware breakpoints (gdb 'hbreak' cmd) to break at _startup.
	  xt-gdb can't place a Software Breakpoint in the  0XD region prior
	  to mapping the MMU and after mapping even if the area of low memory
	  was mapped gdb wouldn't remove the breakpoint on hitting it as the
	  PC wouldn't match. Since Hardware Breakpoints are recommended for
	  Linux configurations it seems reasonable to just assume they exist
	  and leave this older mechanism for unfortunate souls that choose
	  not to follow Tensilica's recommendation.

	  Selecting this will cause U-Boot to set the KERNEL Load and Entry
	  address at 0x00003000 instead of the mapped std of 0xD0003000.

	  If in doubt, say Y.

config HIGHMEM
	bool "High Memory Support"
	help
	  Linux can use the full amount of RAM in the system by
	  default. However, the default MMUv2 setup only maps the
	  lowermost 128 MB of memory linearly to the areas starting
	  at 0xd0000000 (cached) and 0xd8000000 (uncached).
	  When there are more than 128 MB memory in the system not
	  all of it can be "permanently mapped" by the kernel.
	  The physical memory that's not permanently mapped is called
	  "high memory".

	  If you are compiling a kernel which will never run on a
	  machine with more than 128 MB total physical RAM, answer
	  N here.

	  If unsure, say Y.

endmenu

config XTENSA_CALIBRATE_CCOUNT
	def_bool n
	help
	  On some platforms (XT2000, for example), the CPU clock rate can
	  vary.  The frequency can be determined, however, by measuring
	  against a well known, fixed frequency, such as an UART oscillator.

config SERIAL_CONSOLE
	def_bool n

menu "Bus options"

config PCI
	bool "PCI support"
	default y
	help
	  Find out whether you have a PCI motherboard. PCI is the name of a
	  bus system, i.e. the way the CPU talks to the other stuff inside
	  your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
	  VESA. If you have PCI, say Y, otherwise N.

source "drivers/pci/Kconfig"

endmenu

menu "Platform options"

choice
	prompt "Xtensa System Type"
	default XTENSA_PLATFORM_ISS

config XTENSA_PLATFORM_ISS
	bool "ISS"
	select XTENSA_CALIBRATE_CCOUNT
	select SERIAL_CONSOLE
	help
	  ISS is an acronym for Tensilica's Instruction Set Simulator.

config XTENSA_PLATFORM_XT2000
	bool "XT2000"
	help
	  XT2000 is the name of Tensilica's feature-rich emulation platform.
	  This hardware is capable of running a full Linux distribution.

config XTENSA_PLATFORM_S6105
	bool "S6105"
	select SERIAL_CONSOLE
	select NO_IOPORT_MAP

config XTENSA_PLATFORM_XTFPGA
	bool "XTFPGA"
	select SERIAL_CONSOLE
	select ETHOC
	select XTENSA_CALIBRATE_CCOUNT
	help
	  XTFPGA is the name of Tensilica board family (LX60, LX110, LX200, ML605).
	  This hardware is capable of running a full Linux distribution.

endchoice


config XTENSA_CPU_CLOCK
	int "CPU clock rate [MHz]"
	depends on !XTENSA_CALIBRATE_CCOUNT
	default 16

config GENERIC_CALIBRATE_DELAY
	bool "Auto calibration of the BogoMIPS value"
	help
	  The BogoMIPS value can easily be derived from the CPU frequency.

config CMDLINE_BOOL
	bool "Default bootloader kernel arguments"

config CMDLINE
	string "Initial kernel command string"
	depends on CMDLINE_BOOL
	default "console=ttyS0,38400 root=/dev/ram"
	help
	  On some architectures (EBSA110 and CATS), there is currently no way
	  for the boot loader to pass arguments to the kernel. For these
	  architectures, you should supply some command-line options at build
	  time by entering them here. As a minimum, you should specify the
	  memory size and the root device (e.g., mem=64M root=/dev/nfs).

config USE_OF
	bool "Flattened Device Tree support"
	select OF
	select OF_EARLY_FLATTREE
	help
	  Include support for flattened device tree machine descriptions.

config BUILTIN_DTB
	string "DTB to build into the kernel image"
	depends on OF

config BLK_DEV_SIMDISK
	tristate "Host file-based simulated block device support"
	default n
	depends on XTENSA_PLATFORM_ISS
	help
	  Create block devices that map to files in the host file system.
	  Device binding to host file may be changed at runtime via proc
	  interface provided the device is not in use.

config BLK_DEV_SIMDISK_COUNT
	int "Number of host file-based simulated block devices"
	range 1 10
	depends on BLK_DEV_SIMDISK
	default 2
	help
	  This is the default minimal number of created block devices.
	  Kernel/module parameter 'simdisk_count' may be used to change this
	  value at runtime. More file names (but no more than 10) may be
	  specified as parameters, simdisk_count grows accordingly.

config SIMDISK0_FILENAME
	string "Host filename for the first simulated device"
	depends on BLK_DEV_SIMDISK = y
	default ""
	help
	  Attach a first simdisk to a host file. Conventionally, this file
	  contains a root file system.

config SIMDISK1_FILENAME
	string "Host filename for the second simulated device"
	depends on BLK_DEV_SIMDISK = y && BLK_DEV_SIMDISK_COUNT != 1
	default ""
	help
	  Another simulated disk in a host file for a buildroot-independent
	  storage.

source "mm/Kconfig"

source "drivers/pcmcia/Kconfig"

source "drivers/pci/hotplug/Kconfig"

endmenu

menu "Executable file formats"

source "fs/Kconfig.binfmt"

endmenu

source "net/Kconfig"

source "drivers/Kconfig"

source "fs/Kconfig"

source "arch/xtensa/Kconfig.debug"

source "security/Kconfig"

source "crypto/Kconfig"

source "lib/Kconfig"