nuttx/arch/Kconfig

#
# For a description of the syntax of this configuration file,
# see the file kconfig-language.txt in the NuttX tools repository.
#

choice
	prompt "CPU Architecture"
	default ARCH_ARM

config ARCH_ARM
	bool "ARM"
	select ARCH_HAVE_INTERRUPTSTACK
	select ARCH_HAVE_TLS
	select ARCH_HAVE_VFORK
	select ARCH_HAVE_STACKCHECK
	select ARCH_HAVE_CUSTOMOPT
	---help---
		The ARM architectures

config ARCH_AVR
	bool "AVR"
	select ARCH_NOINTC
	select ARCH_HAVE_INTERRUPTSTACK
	select ARCH_HAVE_CUSTOMOPT
	---help---
		Atmel 8-bit bit AVR and 32-bit AVR32 architectures

config ARCH_HC
	bool "Freescale HC"
	select ARCH_NOINTC
	select ARCH_HAVE_INTERRUPTSTACK
	---help---
		Freescale HC architectures (M9S12)

config ARCH_MIPS
	bool "MIPS"
	select ARCH_HAVE_INTERRUPTSTACK
	select ARCH_HAVE_CUSTOMOPT
	---help---
		MIPS architectures (PIC32)

config ARCH_MISOC
	bool "MISOC"
	select ARCH_HAVE_INTERRUPTSTACK
	select ARCH_HAVE_CUSTOMOPT
	---help---
		MISOC

config ARCH_RENESAS
	bool "Renesas"
	select ARCH_NOINTC
	select ARCH_HAVE_INTERRUPTSTACK
	---help---
		Renesas architectures (SH and M16C).

config ARCH_RISCV
	bool "RISC-V"
	select ARCH_HAVE_INTERRUPTSTACK
	select ARCH_HAVE_CUSTOMOPT
	---help---
		RISC-V 32 and 64-bit RV32 / RV64 architectures.

config ARCH_SIM
	bool "Simulation"
	select ARCH_HAVE_MULTICPU
	select ARCH_HAVE_TLS
	select ARCH_HAVE_TICKLESS
	select ARCH_HAVE_POWEROFF
	select ARCH_HAVE_TESTSET
	select SERIAL_CONSOLE
	---help---
		Linux/Cywgin user-mode simulation.

config ARCH_X86
	bool "x86"
	---help---
		Intel x86 architectures.

config ARCH_XTENSA
	bool "Xtensa"
	select ARCH_HAVE_STACKCHECK
	select ARCH_HAVE_CUSTOMOPT
	select ARCH_HAVE_TESTSET
	---help---
		Cadence® Tensilica® Xtensa® actictures.

config ARCH_Z16
	bool "ZNEO"
	select ARCH_HAVE_HEAP2
	---help---
		ZiLOG ZNEO 16-bit architectures (z16f).

config ARCH_Z80
	bool "z80"
	select ARCH_HAVE_HEAP2
	---help---
		ZiLOG 8-bit architectures (z80, ez80, z8).

config ARCH_OR1K
	bool "OpenRISC"
	---help---
		OpenRISC architectures.

endchoice

config ARCH
	string
	default "arm"     if ARCH_ARM
	default "avr"     if ARCH_AVR
	default "hc"      if ARCH_HC
	default "mips"    if ARCH_MIPS
	default "misoc"   if ARCH_MISOC
	default "renesas" if ARCH_RENESAS
	default "risc-v"  if ARCH_RISCV
	default "sim"     if ARCH_SIM
	default "x86"     if ARCH_X86
	default "xtensa"  if ARCH_XTENSA
	default "z16"     if ARCH_Z16
	default "z80"     if ARCH_Z80
	default "or1k"    if ARCH_OR1K

source arch/arm/Kconfig
source arch/avr/Kconfig
source arch/hc/Kconfig
source arch/mips/Kconfig
source arch/misoc/Kconfig
source arch/renesas/Kconfig
source arch/risc-v/Kconfig
source arch/sim/Kconfig
source arch/x86/Kconfig
source arch/xtensa/Kconfig
source arch/z16/Kconfig
source arch/z80/Kconfig
source arch/or1k/Kconfig

config ARCH_TOOLCHAIN_IAR
	bool
	default n

config ARCH_TOOLCHAIN_GNU
	bool
	default n

config ARCH_GNU_NO_WEAKFUNCTIONS
	bool
	depends on ARCH_TOOLCHAIN_GNU
	default n
	---help---
		Disable support for weak functions.

comment "Architecture Options"

config ARCH_NOINTC
	bool
	default n

config ARCH_VECNOTIRQ
	bool
	default n

config ARCH_HAVE_IRQTRIGGER
	bool
	default n
	depends on !ARCH_NOINTC

config ARCH_DMA
	bool
	default n

config ARCH_HAVE_IRQPRIO
	bool
	default n

config ARCH_ICACHE
	bool
	default n

config ARCH_DCACHE
	bool
	default n

config ARCH_L2CACHE
	bool
	default n

config ARCH_HAVE_ADDRENV
	bool
	default n

config ARCH_NEED_ADDRENV_MAPPING
	bool
	default n

config ARCH_HAVE_MULTICPU
	bool
	default n

config ARCH_HAVE_VFORK
	bool
	default n

config ARCH_HAVE_FPU
	bool
	default n

config ARCH_HAVE_DPFPU
	bool
	default n

config ARCH_HAVE_LAZYFPU
	bool

config ARCH_HAVE_MMU
	bool
	default n

config ARCH_HAVE_MPU
	bool
	default n

config ARCH_NAND_HWECC
	bool
	default n

config ARCH_HAVE_EXTCLK
	bool
	default n

config ARCH_HAVE_POWEROFF
	bool
	default n

config ARCH_HAVE_PROGMEM
	bool
	default n

config ARCH_HAVE_RESET
	bool
	default n

config ARCH_HAVE_TESTSET
	bool
	default n

config ARCH_HAVE_FETCHADD
	bool
	default n

config ARCH_HAVE_RTC_SUBSECONDS
	bool
	default n

config ARCH_HAVE_GARBAGE
	bool
	default n

config ARCH_GLOBAL_IRQDISABLE
	bool
	default n
	---help---
		Indicates that disabling interrupts on one CPU will either (1) disable
		all interrupts globally on all CPUs, or (2) will disable interprocessor
		interrupts as well so that no context switches can occur on the CPU
		that disabled "local" interrupts.

config ARCH_FPU
	bool "FPU support"
	default y
	depends on ARCH_HAVE_FPU
	---help---
		Build in support for the Floating Point Unit (FPU).
		Check your chip specifications first; not all chips support the FPU.

config ARCH_DPFPU
	bool "Double precision FPU support"
	default y
	depends on ARCH_FPU && ARCH_HAVE_DPFPU
	---help---
		Enable toolchain support for double precision (64-bit) floating
		point if both the toolchain and the hardware support it.

config ARCH_USE_MMU
	bool "Enable MMU"
	default n
	depends on ARCH_HAVE_MMU
	---help---
		The architecture supports supports an MMU.  Enable this option in
		order to enable use of the MMU.  For most architectures, this is
		not really an option:  It is required to use the MMU.  In those
		cases, this selection will always be forced.

config ARCH_USE_MPU
	bool "Enable MPU"
	default n
	depends on ARCH_HAVE_MPU
	---help---
		The architecture supports supports an MPU.  Enable this option in
		order to enable use of the MPU.  For most architectures, this option
		is enabled by other, platform-specific logic.  In those cases, this
		selection will always be forced.

menuconfig ARCH_ADDRENV
	bool "Address environments"
	default n
	depends on ARCH_HAVE_ADDRENV
	---help---
		Support per-task address environments using the MMU... i.e., support
		"processes"

if ARCH_ADDRENV && ARCH_NEED_ADDRENV_MAPPING

config ARCH_TEXT_VBASE
	hex "Virtual .text base"
	---help---
		The virtual address of the beginning the .text region

config ARCH_DATA_VBASE
	hex "Virtual .bss/.data base"
	---help---
		The virtual address of the beginning of the .bss/.data region.

config ARCH_HEAP_VBASE
	hex "Virtual heap base"
	---help---
		The virtual address of the beginning of the heap region.

config ARCH_SHM_VBASE
	hex "Shared memory base"
	depends on MM_SHM
	---help---
		The virtual address of the beginning of the shared memory region.

config ARCH_TEXT_NPAGES
	int "Max .text pages"
	default 1
	---help---
		The maximum number of pages that can allocated for the .text region.
		This, along with knowledge of the page size, determines the size of
		the .text virtual address space. Default is 1.

config ARCH_DATA_NPAGES
	int "Max .bss/.data pages"
	default 1
	---help---
		The maximum number of pages that can allocated for the .bss/.data
		region. This, along with knowledge of the page size, determines the
		size of the .bss/.data virtual address space. Default is 1.

config ARCH_HEAP_NPAGES
	int "Max heap pages"
	default 1
	---help---
		The maximum number of pages that can allocated for the heap region.
		This, along with knowledge of the page size, determines the size of
		the heap virtual address space. Default is 1.

if MM_SHM

config ARCH_SHM_MAXREGIONS
	int "Max shared memory regions"
	default 1
	---help---
		The maximum number of regions that can allocated for the shared
		memory space.  This hard-coded value permits static allocation of
		the shared memory data structures and serves no other purpose.
		Default is 1.

		The size of the virtual shared memory address space is then
		determined by the product of the maximum number of regions, the
		maximum number of pages per region, and the configured size of
		each page.

config ARCH_SHM_NPAGES
	int "Max shared memory pages"
	default 1
	---help---
		The maximum number of pages that can allocated per region for the shared memory
		region. Default is 1.

		The size of the virtual shared memory address space is then
		determined by the product of the maximum number of regions, the
		maximum number of pages per region, and the configured size of
		each page.

endif # MM_SHM

config ARCH_STACK_DYNAMIC
	bool "Dynamic user stack"
	default n
	depends on BUILD_KERNEL && EXPERIMENTAL
	---help---
		Select this option if the user process stack resides in its own
		address space.  The naming of this selection implies that dynamic
		stack allocation is supported.  Certainly this option must be set if
		dynamic stack allocation is supported by a platform.  But the more
		general meaning of this configuration environment is simply that the
		stack has its own address space.

		NOTE:  This option not yet fully implemented in the code base.
		Hence, it is marked EXPERIMENTAL:  Do not enable it unless you plan
		finish the implementation.

if ARCH_STACK_DYNAMIC

config ARCH_STACK_VBASE
	hex "Virtual stack base"
	---help---
		The virtual address of the beginning the stack region

config ARCH_STACK_NPAGES
	int "Max. stack pages"
	default 1
	---help---
		The maximum number of pages that can allocated for the stack region.
		This, along with knowledge of the page size, determines the size of
		the stack virtual address space. Default is 1.

endif # ARCH_STACK_DYNAMIC

config ARCH_KERNEL_STACK
	bool "Kernel process stack"
	default n if !LIBC_EXECFUNCS
	default y if LIBC_EXECFUNCS
	depends on BUILD_KERNEL
	---help---
		It this option is selected, then every user process will have two
		stacks:  A large, potentially dynamically sized user stack and small
		kernel stack that is used during system call process.

		If this option is not selected, then kernel system calls will simply
		use the caller's user stack.  So, in most cases, this option is not
		required.  However, this option is *required* if both BUILD_KERNEL
		and LIBC_EXECFUNCS are selected.  Why?  Because when we instantiate
		and initialize the address environment of the new user process, we
		will temporarily lose the address environment of the old user
		process, including its stack contents.  The kernel C logic will
		crash immediately with no valid stack in place.

		When this option is selected, the smaller kernel stack stays in
		place during system call processing event though the original user
		stack may or may not be accessible.

if ARCH_KERNEL_STACK

config ARCH_KERNEL_STACKSIZE
	int "Kernel stack size"
	default 1568
	---help---
		The common size of each process' kernel stack

endif # ARCH_KERNEL_STACK

config ARCH_PGPOOL_MAPPING
	bool "Have page pool mapping"
	default n
	---help---
		If there is a MMU mapping in place for the page pool memory, then
		this mapping can be utilized to simplify some page table operations.
		Otherwise, a temporary mapping will have to be established each time
		it is necessary to modify the contents of a page.

if ARCH_PGPOOL_MAPPING

config ARCH_PGPOOL_PBASE
	hex "Page pool physical address"
	default 0x0
	---help---
		The physical address of the start of the page pool memory.  This
		setting is probably equivalent to other platform specific definitions
		but is required again in order to modularize the common address
		environment logic.

config ARCH_PGPOOL_VBASE
	hex "Page pool virtual address"
	default 0x0
	---help---
		The virtual address of the start of the page pool memory.  This
		setting is probably equivalent to other platform specific definitions
		but is required again in order to modularize the common address
		environment logic.

config ARCH_PGPOOL_SIZE
	int "Page pool size (bytes)"
	default 0
	---help---
		The size of the page pool memory in bytes.  This setting is probably
		equivalent  to other platform specific definitions but is required again
		in order to modularize the common address environment logic.

endif # ARCH_PGPOOL_MAPPING
endif # ARCH_ADDRENV && ARCH_NEED_ADDRENV_MAPPING

menuconfig PAGING
	bool "On-demand paging"
	default n
	depends on ARCH_USE_MMU && !ARCH_ROMPGTABLE
	---help---
		If set =y in your configation file, this setting will enable the on-demand
		paging feature as described in http://www.nuttx.org/NuttXDemandPaging.html.

if PAGING

config PAGING_PAGESIZE
	int "Page size (bytes)"
	default 4096
	---help---
		The size of one managed page.  This must be a value supported by the
		processor's memory management unit

config PAGING_NLOCKED
	int "Number of locked pages"
	default 48
	---help---
		This is the number of locked pages in the memory map.

config PAGING_CUSTOM_BASE
	bool "Custom paging base address"
	default n
	---help---
		By default, the page begins at RAM_START/VSTART.  That base address
		can be changed if this value is selected.

if PAGING_CUSTOM_BASE

config PAGING_LOCKED_PBASE
	hex "Physical base address"

config PAGING_LOCKED_VBASE
	hex "Virtual base address"

endif # PAGING_CUSTOM_BASE

config PAGING_NPPAGED
	int "Number of physical pages"
	default 256
	---help---
		This is the number of physical pages available to support the paged
		text region.

config PAGING_NVPAGED
	int "Number of virtual pages"
	default 1024
	---help---
		This actual size of the virtual paged text region (in pages).  This
		is also the number of virtual pages required to span the entire
		paged region. The on-demand paging  feature is intended to support
		only the case where the virtual paged text area is much larger the
		available physical pages.  Otherwise, why would you enable on-demand paging?

config PAGING_NDATA
	int "Number of data pages"
	default 256
	---help---
		This is the number of data pages in the memory map.  The data region
		will extend to the end of RAM unless overridden by a setting in the
		configuration file.

		NOTE:  In some architectures, it may be necessary to take some memory
		from the end of RAM for page tables or other system usage.  The
		configuration settings and linker directives must be cognizant of
		that: PAGING_NDATA should be defined to prevent the data region from
		extending all the way to the end of memory.

config PAGING_DEFPRIO
	int "Page fill worker thread priority"
	default 100
	---help---
		The default, minimum priority of the page fill worker thread.  The
		priority of the page fill work thread will be boosted  boosted
		dynamically so that it matches the priority of the task on behalf
		of which it performs the fill.  This defines the minimum priority
		that will be used. Default: 100.

config PAGING_STACKSIZE
	int "Page fill worker thread stack size"
	default 1024
	---help---
		Defines the size of the allocated stack for the page fill worker
		thread. Default: 1024.

config PAGING_BLOCKINGFILL
	bool "Blocking fill"
	default n
	---help---
		The architecture specific up_fillpage() function may be blocking
		or non-blocking.  If defined, this setting indicates that the
		up_fillpage() implementation will block until the transfer is
		completed. Default:  Undefined (non-blocking).

config PAGING_WORKPERIOD
	int "Work period (usec)"
	default 500000
	---help---
		The page fill worker thread will wake periodically even if there
		is no mapping to do.  This selection controls that wake-up period
		(in microseconds).  This wake-up a failsafe that will handle any
		cases where a single is lost (that would really be a bug and
		shouldn't happen!) and also supports timeouts for case of non-
		blocking, asynchronous fills (see CONFIG_PAGING_TIMEOUT_TICKS).

config PAGING_TIMEOUT
	bool "Paging timeout"
	default n
	---help---
		If defined, the implementation will monitor the (asynchronous) page
		fill logic.  If the fill takes longer than than a timeout value,
		then a fatal error will be declared. Default: No timeouts monitored

config PAGING_TIMEOUT_TICKS
	int "Paging timeout ticks"
	default 10
	depends on PAGING_TIMEOUT
	---help---
		If PAGING_TIMEOUT is defined, then implementation will monitor the
		(asynchronous) page fill logic.  If the fill takes longer than this
		number if microseconds, then a fatal error will be declared.
		Default: No timeouts monitored

endif # PAGING

config ARCH_IRQPRIO
	bool "Prioritized interrupt support"
	default n
	depends on ARCH_HAVE_IRQPRIO
	---help---
		Enable support for prioritized interrupts.

		NOTE: The use of interrupt priorities implies that you also have
		support for nested interrupts.  Most architectures do not support
		nesting of interrupts or, if they do, they only supported nested
		interrupts with certain configuration options.  So this selection
		should be used with caution.

config ARCH_STACKDUMP
	bool "Dump stack on assertions"
	default n
	select DEBUG_ALERT
	---help---
		Enable to do stack dumps after assertions

config ARCH_USBDUMP
	bool "Dump USB trace data"
	default n
	depends on USBDEV_TRACE
	---help---
		Enable to do USB trace after assertions

config ENDIAN_BIG
	bool "Big Endian Architecture"
	default n
	depends on !ARCH_RISCV
	---help---
		Select if architecture operates using big-endian byte ordering.

config ARCH_IDLE_CUSTOM
	bool "Custom IDLE loop"
	default n
	---help---
		Each architecture provides a "default" IDLE loop that exits when the
		MCU has nothing else to do.  This default IDLE loop can be replaced
		by a custom, board-specific IDLE loop by setting this option.  Such
		a custom IDLE loop may do things like a continuous built-in test or
		perhaps or IDLE low power operations.

		NOTE: As of this writing, this capability is only supported by ARM
		and MIPS architectures.  However, the implementation is trivial:  If
		CONFIG_ARCH_IDLE_CUSTOM is defined, then the default IDLE loop file
		is not included in the MCU-specific Make.defs file.

config ARCH_CUSTOM_PMINIT
	bool "Custom PM initialization"
	default n
	depends on PM
	---help---
		Each architecture provides default power management (PM)
		initialization that is called automatically when the system is
		started. This default PM initialization can be replaced by custom,
		board-specific PM initialization by setting this option.  Such a
		custom initialization may do additional PM-related initialization
		that is unique to the board power management requirements.

		NOTE: As of this writing, this capability is only supported by the
		STM32.  However, the implementation is trivial:  If CONFIG_ARCH_CUSTOM_PMINIT,
		then the default PM initialization is not included in the MCU-specific
		Make.defs file.

config ARCH_HAVE_RAMFUNCS
	bool
	default n

config ARCH_RAMFUNCS
	bool "Copy functions to RAM on startup"
	default y
	depends on ARCH_HAVE_RAMFUNCS
	---help---
		Copy some functions to RAM at boot time.  This is done in some
		architectures to improve performance.  In other cases, it is done
		so that FLASH can be reconfigured while the MCU executes out of
		SRAM.

config ARCH_HAVE_RAMVECTORS
	bool
	default n

config ARCH_RAMVECTORS
	bool "Support RAM interrupt vectors"
	default n
	depends on ARCH_HAVE_RAMVECTORS
	---help---
		If ARCH_RAMVECTORS is defined, then the architecture will support
		modifiable vectors in a RAM-based vector table.

config ARCH_MINIMAL_VECTORTABLE
	bool "Minimal RAM usage for vector table"
	default n
	---help---
		Use a minimum amount of RAM for the vector table.

		Instead of allowing irq_attach() to work for all interrupt vectors,
		restrict to only working for a select few (defined in your board
		configuration). This can dramatically reduce the amount of RAM used
		be your vector table.

		To use this setting, you must have a file in your board config that
		provides:

		  #include <nuttx/arch.h>
		  const irq_mapped_t g_irqmap[NR_IRQS] =
		  {
		    ... IRQ to index mapping values ...
		  };

		This table is index by the hardware IRQ number and provides a value
		in the range of 0 to CONFIG_ARCH_NUSER_INTERRUPTS that is the new,
		mapped index into the vector table.  Unused, unmapped interrupts
		should be set to IRQMAPPED_MAX.  So, for example, if g_irqmap[37]
		== 24, then the hardware interrupt vector 37 will be mapped to the
		interrupt vector table at index 24.  if g_irqmap[42] ==
		IRQMAPPED_MAX, then hardware interrupt vector 42 is not used and
		if it occurs will result in an unexpected interrupt crash.

config ARCH_NUSER_INTERRUPTS
	int "Number of interrupts"
	default 0
	depends on ARCH_MINIMAL_VECTORTABLE
	---help---
		If CONFIG_ARCH_MINIMAL_VECTORTABLE is defined, then this setting
		defines the actual number of valid, mapped interrupts in g_irqmap.
		This number will be the new size of the OS vector table

# Bring-up debug configuration options.  These are only intended for low level
# bring-up and not part of normal platform configuration.  They should never be
# selected in a "normal" configuration and, hence, depend on both EXPERIMENTAL
# and DEBUG_FEATURES.

menu "Bring-Up Options"
	depends on EXPERIMENTAL && DEBUG_FEATURES

config SUPPRESS_CLOCK_CONFIG
	bool "Suppress clock configuration"
	default n
	depends on ARCH_XTENSA
	---help---
		Do not configure clocking.  Instead relies on the reset clock
		configuration (or clock configuration provided by a bootloader).

config SUPPRESS_INTERRUPTS
	bool "Suppress all interrupts"
	default n
	---help---
		Do not enable interrupts

config SUPPRESS_TIMER_INTS
	bool "No timer"
	default n
	---help---
		Do not initialize or enable the system timer

config SUPPRESS_SERIAL_INTS
	bool "Suppress serial interrupts"
	default n
	---help---
		Console will poll

config SUPPRESS_UART_CONFIG
	bool "Do no re-configure UART"
	default n
	---help---
		Do not re-configure the serial console UART from its start-up state.
		This is useful when a boot loader has already initialized the serial
		port.

config DUMP_ON_EXIT
	bool "Dump task state"
	default n
	depends on DEBUG_SCHED_INFO
	---help---
		Dump task state on exit()

endmenu # Bring-Up Options

comment "Board Settings"

config BOARD_LOOPSPERMSEC
	int "Delay loops per millisecond"
	default 5000
	---help---
		Simple delay loops are used by some logic, especially during boot-up,
		driver initialization.  These delay loops must be calibrated for each
		board in order to assure accurate timing by the delay loops.

comment "Interrupt options"

config ARCH_HAVE_INTERRUPTSTACK
	bool
	default n

config ARCH_INTERRUPTSTACK
	int "Interrupt Stack Size"
	depends on ARCH_HAVE_INTERRUPTSTACK
	default 0
	---help---
		This architecture supports an interrupt stack. If defined, this symbol
		will be the size of the interrupt stack in bytes.  If not defined (or
		defined to be zero), the user task stacks will be used during interrupt
		handling.

config ARCH_HAVE_HIPRI_INTERRUPT
	bool
	default n

config ARCH_HIPRI_INTERRUPT
	bool "High priority interrupts"
	default n
	depends on ARCH_HAVE_HIPRI_INTERRUPT && ARCH_HAVE_IRQPRIO
	select ARCH_IRQPRIO
	---help---
		NOTE: This description is currently unique to the Cortex-M family
		which is the only family that currently supports this feature.  The
		general feature is not conceptually unique to the Cortex-M but if it
		is extended to any other family, then this discussion will have to
		be generalized.

		If ARMV7M_USEBASEPRI is selected, then interrupts will be disabled
		by setting the BASEPRI register to NVIC_SYSH_DISABLE_PRIORITY so
		that most interrupts will not have execution priority.  SVCall must
		have execution priority in all cases.

		In the normal cases, interrupts are not nest-able and all interrupts
		run at an execution priority between NVIC_SYSH_PRIORITY_MIN and
		NVIC_SYSH_PRIORITY_MAX (with NVIC_SYSH_PRIORITY_MAX reserved for
		SVCall).

		If, in addition, ARCH_HIPRI_INTERRUPT is defined, then special high
		priority interrupts are supported.  These are not "nested" in the
		normal sense of the word.  These high priority interrupts can
		interrupt normal processing but execute outside of OS (although they
		can "get back into the game" via a PendSV interrupt).

		How do you specify a high priority interrupt?  You need to do two
		things:

			1) You need to change the address in the vector table so that
			   the high priority interrupt vectors to your special C
			   interrupt handler.  There are two ways to do this:

			   a) If you select CONFIG_ARCH_RAMVECTORS, then vectors will
			      be kept in RAM and the system will support the interface:

			      int up_ramvec_attach(int irq, up_vector_t vector)

			      that can be used to attach your C interrupt handler to the
			      vector at run time.

			   b) Alternatively, you could keep your vectors in FLASH but in
			      order to this, you would have to develop your own custom
			      vector table.

			2) Then set the priority of your interrupt to NVIC to
			   NVIC_SYSH_HIGH_PRIORITY using the standard interface:

			   int up_prioritize_irq(int irq, int priority)

		NOTE: ARCH_INTERRUPTSTACK must be set in kernel mode (BUILD_KERNEL).
		In kernel mode without an interrupt stack, the interrupt handler
		will set the MSP to the stack pointer of the interrupted thread.  If
		the interrupted thread was a privileged thread, that will be the MSP
		otherwise it will be the PSP.  If the PSP is used, then the value of
		the MSP will be invalid when the interrupt handler returns because
		it will be a pointer to an old position in the unprivileged stack.
		Then when the high priority interrupt occurs and uses this stale MSP,
		there will most likely be a system failure.

		If the interrupt stack is selected, on the other hand, then the
		interrupt handler will always set the MSP to the interrupt
		stack.  So when the high priority interrupt occurs, it will either
		use the MSP of the last privileged thread to run or, in the case of
		the nested interrupt, the interrupt stack if no privileged task has
		run

comment "Boot options"

choice
	prompt "Boot Mode"
	default BOOT_RUNFROMFLASH

config BOOT_RUNFROMEXTSRAM
	bool "Run from external SRAM"
	---help---
		Some configuration support booting and running from external SRAM.

config BOOT_RUNFROMFLASH
	bool "Boot and run from flash"
	---help---
		Most configurations support XIP operation from FLASH but must copy
		initialized .data sections to RAM. (This is the default).

config BOOT_RUNFROMISRAM
	bool "Boot and run from internal SRAM"
	---help---
		Some configuration support booting and running from internal SRAM.

config BOOT_RUNFROMSDRAM
	bool "Boot and run from external SDRAM"
	---help---
		Some configuration support booting and running from external SDRAM.

config BOOT_COPYTORAM
	bool "Boot from FLASH but copy to ram"
	---help---
		Some configurations boot in FLASH but copy themselves entirely into
		RAM for better performance.

endchoice

menu "Boot Memory Configuration"

config RAM_START
	hex "Primary RAM start address (physical)"
	default 0x0
	help
		The physical start address of primary installed RAM.  "Primary" RAM
		refers to the RAM that you link program code into.  If program code
		does not execute out of RAM but from FLASH, then you may designate
		any block of RAM as "primary."

config RAM_VSTART
	hex "Primary RAM start address (virtual)"
	default 0x0
	depends on ARCH_USE_MMU
	help
		The virtual start address of installed primary RAM. "Primary" RAM
		refers to the RAM that you link program code into.  If program code
		does not execute out of RAM but from FLASH, then you may designate
		any block of RAM as "primary."

config RAM_SIZE
	int "Primary RAM size"
	default 0
	help
		The size in bytes of the installed primary RAM. "Primary" RAM
		refers to the RAM that you link program code into.  If program code
		does not execute out of RAM but from FLASH, then you may designate
		any block of RAM as "primary."

if BOOT_RUNFROMFLASH && ARCH_USE_MMU

config FLASH_START
	hex "Boot FLASH start address (physical)"
	default 0x0
	help
		The physical start address of installed boot FLASH.  "Boot" FLASH
		refers to the FLASH that you link program code into.

config FLASH_VSTART
	hex "Boot FLASH start address (virtual)"
	default 0x0
	help
		The virtual start address of installed boot FLASH.  "Boot" FLASH
		refers to the FLASH that you link program code into.

config FLASH_SIZE
	int "Boot FLASH size"
	default 0
	help
		The size in bytes of the installed boot FLASH.  "Boot" FLASH
		refers to the FLASH that you link program code into.

endif # BOOT_RUNFROMFLASH && ARCH_USE_MMU

config ARCH_HAVE_SDRAM
	bool
	default n

config BOOT_SDRAM_DATA
	bool "Data in SDRAM"
	default n
	depends on ARCH_HAVE_SDRAM && !BOOT_RUNFROMSDRAM
	---help---
		This selection should be set if data lies in SDRAM (vs. SRAM) and if
		SDRAM was not previously initialized by a loader.  Obviously, this
		does not apply if we booting from SDRAM because SDRAM must have been
		initialized priority to loading NuttX into SDRAM.

		In the case where SDRAM must be initialized by NuttX, the
		initialization sequence is a little different: Normally, .data and
		.bss must be initialized before starting the system.  But in this
		case SDRAM must be configured by board-specific logic before the
		.data and .bss sections can be initialized.

endmenu # Boot Memory Configuration