Architecture-Specific Code ^^^^^^^^^^^^^^^^^^^^^^^^^^ Table of Contents ^^^^^^^^^^^^^^^^^ o Architecture-Specific Code o Summary of Files o Supported Architectures o Configuring NuttX Architecture-Specific Code ^^^^^^^^^^^^^^^^^^^^^^^^^^ The file include/nuttx/arch.h identifies all of the APIs that must be provided by the architecture specific logic. (It also includes arch//arch.h as described below). Directory Structure ^^^^^^^^^^^^^^^^^^^ Thie arch directory contains architecture specific logic. Each aructure provide a a subdirectory under arch/ with the folling characteristics: |-- Make.defs |-- defconfig |-- setenv.sh |-- include | |-- arch.h | |-- irq.h | `-- types.h `-- src |-- Makefile `-- (architecture-specific source files) Summary of Files ^^^^^^^^^^^^^^^^ Make.defs -- This makefile fragment provides architecture and tool-specific build options. It will be included by all other makefiles in the build (once it is installed). This make fragment should define: Tools: CC, LD, AR, NM, OBJCOPY, OBJDUMP Tool options: CFLAGS, LDFLAGS When this makefile fragment runs, it will be passed TOPDIR which is the path to the root directory of the build. This makefile fragment may include ${TOPDIR}/.config to perform configuration specific settings. For example, the CFLAGS will most likely be different if CONFIG_DEBUG=y. defconfig -- This is a configuration file similar to the Linux configuration file. In contains varialble/value pairs like: CONFIG_VARIABLE=value This configuration file will be used at build time: (1) as a makefile fragment included in other makefiles, and (2) to generate include/nuttx/config.h which is included by most C files in the system. The following variables are recognized by the build (you may also include architecture-specific settings). Architecture selection: CONFIG_ARCH - identifies the arch subdirectory CONFIG_ARCH_name - for use in C code General OS setup CONFIG_EXAMPLE - identifies the subdirectory in examples that will be used in the build CONFIG_DEBUG - enables built-in debug options CONFIG_DEBUG_VERBOSE - enables verbose debug output CONFIG_HAVE_LOWPUTC - architecture supports low-level, boot time console output CONFIG_MM_REGIONS - If the architecture includes multiple regions of memory to allocate from, this specifies the number of memory regions that the memory manager must handle and enables the API mm_addregion(start, end); CONFIG_RR_INTERVAL - The round robin timeslice will be set this number of milliseconds; Round robin scheduling can be disabled by setting this value to zero. CONFIG_SCHED_INSTRUMENTATION - enables instrumentation in scheduler to monitor system performance CONFIG_TASK_NAME_SIZE - Spcifies that maximum size of a task name to save in the TCB. Useful if scheduler instrumentation is selected. Set to zero to disable. CONFIG_START_YEAR, CONFIG_START_MONTH, CONFIG_START_DAY - Used to initialize the internal time logic. CONFIG_JULIAN_TIME - Enables Julian time conversions CONFIG_DEV_CONSOLE - Set if architecture-specific logic provides /dev/console. Enables stdout, stderr, stdin. The following can be used to disable categories of APIs supported by the OS. If the compiler supports weak functions, then it should not be necessary to disable functions unless you want to restrict usage of those APIs. There are certain dependency relationships in these features. o mq_notify logic depends on signals to awaken tasks waiting for queues to become full or empty. o pthread_condtimedwait() depends on signals to wake up waiting tasks. CONFIG_DISABLE_CLOCK, CONFIG_DISABLE_PTHREAD. CONFIG_DISABLE_SIGNALS, CONFIG_DISABLE_MQUEUE Misc libc settings CONFIG_NOPRINTF_FIELDWIDTH - sprintf-related logic is a little smaller if we do not support fieldwidthes Allow for architecture optimized implementations The architecture can provide optimized versions of the following to improve sysem performance CONFIG_ARCH_MEMCPY, CONFIG_ARCH_MEMCMP, CONFIG_ARCH_MEMMOVE CONFIG_ARCH_MEMSET, CONFIG_ARCH_STRCMP, CONFIG_ARCH_STRCPY CONFIG_ARCH_STRNCPY, CONFIG_ARCH_STRLEN, CONFIG_ARCH_BZERO CONFIG_ARCH_KMALLOC, CONFIG_ARCH_KZMALLOC, CONFIG_ARCH_KFREE Sizes of configurable things (0 disables) CONFIG_MAX_TASKS - The maximum number of simultaneously active tasks. This value must be a power of two. CONFIG_NPTHREAD_KEYS - The number of items of thread- specific data that can be retained CONFIG_NFILE_DESCRIPTORS - The maximum number of file descriptors (one for each open) CONFIG_NFILE_STREAMS - The maximum number of streams that can be fopen'ed CONFIG_STDIO_BUFFER_SIZE - Size of the buffer to allocate on fopen. (Only if CONFIG_NFILE_STREAMS > 0) CONFIG_NUNGET_CHARS - Number of characters that can be buffered by ungetc() (Only if CONFIG_NFILE_STREAMS > 0) CONFIG_PREALLOC_MQ_MSGS - The number of pre-allocated message structures. The system manages a pool of preallocated message structures to minimize dynamic allocations CONFIG_MQ_MAXMSGSIZE - Message structures are allocated with a fixed payload size given by this settin (does not include other message structure overhead. CONFIG_PREALLOC_WDOGS - The number of pre-allocated watchdog structures. The system manages a pool of preallocated watchdog structures to minimize dynamic allocations Stack and heap information CONFIG_BOOT_FROM_FLASH - Some configurations support XIP operation from FLASH. CONFIG_STACK_POINTER - The initial stack pointer CONFIG_PROC_STACK_SIZE - The size of the initial stack CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size CONFIG_HEAP_BASE - The beginning of the heap CONFIG_HEAP_SIZE - The size of the heap setenv.sh -- This is a script that you can include that will be installed at the toplevel of the directory structure and can be sourced to set any necessary environment variables. include/arch.h This is a hook for any architecture specific definitions that may be needed by the system. It is included by include/nuttx/arch.h include/types.h This provides architecture/toolchain-specific definitions for standard types. This file should typedef: sbyte, ubyte, uint8, boolean, sint16, uint16, sint32, uint32 and sint64, uint64 if the architecture supports 64-bit integers. irqstate_t Must be defined to the be the size required to hold the interrupt enable/disable state. This file will be included by include/sys/types.h and be made available to all files. include/irq.h This file needs to define some architecture specific functions (usually inline if the compiler supports inlining) and structure. These include: - struct xcptcontext. This structures represents the saved context of a thread. - irqstate_t irqsave(void) -- Used to disable all interrupts. - void irqrestore(irqstate_t flags) -- Used to restore interrupt enables to the same state as before irqsave was called. This file must also define NR_IRQS, the total number of IRQs supported by the board. src/Makefile This makefile will be executed to build the targets src/libup.a and src/up_head.o. The up_head.o file holds the entry point into the system (power-on reset entry point, for example). It will be used in the final link with libup.a and other system archives to generate the final executable. Supported Architectures ^^^^^^^^^^^^^^^^^^^^^^^ arch/c5471 TI TMS320C5471 (also called TMS320DM180). NuttX operates on the ARM7 of this dual core processor. This port uses the Spectrum Digital evaluation board with a GNU arm-elf toolchain*. This port is in progress and partially functional (However, my board is dead at the moment so it will be awhile before I fix it). arch/pjrc-8051 8051 Microcontroller. This port uses the PJRC 87C52 development system and the SDCC toolchain. This port is not quite ready for prime time. arch/sim x86 Linux Simulation. Fully functional. Other ports for the for the TI TMS320DM270 and for MIPS are in various states of progress Configuring NuttX ^^^^^^^^^^^^^^^^^ Configuring NuttX requires only copying arch//Make.def to ${TOPDIR}/Make.defs arch//setenv.sh to ${TOPDIR}/setenv.sh arch//defconfig to ${TOPDIR}/.config There is a script that automates these steps. The following steps will accomplish the same configuration: cd tools ./configure.sh