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author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2007-03-19 22:45:58 +0000 |
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committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2007-03-19 22:45:58 +0000 |
commit | 4c9c2a1787a2e65b1ebd9d20067ed5fe8d5a1072 (patch) | |
tree | 9e9e212d200951b2e6e56702af704fdb31ec1f5e /nuttx/Documentation/NuttxPortingGuide.html | |
parent | 6e5ea64d09237189c40ba4c2e93523cd8c568830 (diff) | |
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git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@105 42af7a65-404d-4744-a932-0658087f49c3
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diff --git a/nuttx/Documentation/NuttxPortingGuide.html b/nuttx/Documentation/NuttxPortingGuide.html index 1065d0097..dee837cd7 100644 --- a/nuttx/Documentation/NuttxPortingGuide.html +++ b/nuttx/Documentation/NuttxPortingGuide.html @@ -11,12 +11,12 @@ <hr> <center> <big><b> - <p>Nuttx Operating System</p> + <p>NuttX Operating System</p> <p>Porting Guide</p> </b></big> <p><small>by</small></p> <p>Gregory Nutt</p> - <p><small>Last Update: February 8, 2007</small></p> + <p><small>Last Update: March 20, 2007</small></p> </center> <center><h1>Table of Contents</h1></center> @@ -25,6 +25,12 @@ <ul> <li>2.1 <a href="#DirStructDocumentation">Documentation</a></li> <l1>2.2 <a href="#DirStructArch">arch</a></li> + <ul> + <li><a href="#sudirectorystructure">2.2.1 Subdirectory Structure</a></li> + <li><a href="#summaryoffiles">2.2.2 Summary of Files</a></li> + <li><a href="#supportedarchitectures">2.2.3 Supported Architectures</a></li> + <li><a href="#configuringnuttx">2.2.4 Configuring NuttX</a></li> + </ul> <li>2.3 <a href="#DirStructDrivers">drivers</a></li> <li>2.4 <a href="#DirStructExamples">examples</a></li> <li>2.5 <a href="#DirStructFs">fs</a></li> @@ -35,12 +41,43 @@ <li>2.10 <a href="#DirStructDrivers">tools</a></li> </ul> <li>3.0 <a href="#DirectoryConfiAndBuild">Configuring and Building</a></li> +<li>4.0 <a href="#ArchAPIs">Architecture APIs</a></li> +<ul> + <li><a href="#imports">4.1 APIs Exported by Architecture-Specific Logic to NuttX</a></li> + <ul> + <li><a href="#upinitialize">4.1.1 <code>up_initialize()</code></a></li> + <li><a href="#upidle">4.1.2 <code>up_idle()</code></a></li> + <li><a href="#upinitialstate">4.1.3 <code>up_initial_state()</code></a></li> + <li><a href="#upcreatestack">4.1.4 <code>up_create_stack()</code></a></li> + <li><a href="#upusestack">4.1.5 <code>up_use_stack()</code></a></li> + <li><a href="#upreleasestack">4.1.6 <code>up_release_stack()</code></a></li> + <li><a href="#upunblocktask">4.1.7 <code>up_unblock_task()</code></a></li> + <li><a href="#upblocktask">4.1.8 <code>up_block_task()</code></a></li> + <li><a href="#upreleasepending">4.1.9 <code>up_release_pending()</code></a></li> + <li><a href="#upreprioritizertr">4.1.10 <code>up_reprioritize_rtr()</code></a></li> + <li><a href="#_exit">4.1.11 <code>_exit()</code></a></li> + <li><a href="#upassert">4.1.12 <code>up_assert()</code></a></li> + <li><a href="#upschedulesigaction">4.1.13 <code>up_schedule_sigaction()</code></a></li> + <li><a href="#upallocateheap">4.1.14 <code>up_allocate_heap()</code></a></li> + <li><a href="#upinterruptcontext">4.1.15 <code>up_interrupt_context()</code></a></li> + <li><a href="#updisableirq">4.1.16 <code>up_disable_irq()</code></a></li> + <li><a href="#upenableirq">4.1.17 <code>up_enable_irq()</code></a></li> + <li><a href="#upputc">4.1.18 <code>up_putc()</code></a></li> + </ul> + <li><a href="#exports">4.2 APIs Exported by NuttX to Architecture-Specific Logic</a></li> + <ul> + <li><a href="#osstart">4.2.1 <code>os_start()</code></a></li> + <li><a href="#listmgmt">4.2.2 OS List Management APIs</a></li></li> + <li><a href="#schedprocesstimer">4.2.3 <code>sched_process_timer()</code></a></li> + <li><a href="#irqdispatch">4.2.4 <code>irq_dispatch()</code></a></li> + </ul> +</ul> <hr> <h1>1.0 <a name="Introduction">Introduction</a></h1> <p><b>Overview</b> - This document provides and overview of the Nuttx build and configuration + This document provides and overview of the NuttX build and configuration logic and provides hints for the incorporation of new processor/board archectures into the build. </p> @@ -53,7 +90,7 @@ <hr> <h1>2.0 <a name="DirectoryStructure">Directory Structure</a></h1> -<p>The general directly layout for Nuttx is very similar to the directory structure +<p>The general directly layout for NuttX is very similar to the directory structure of the Linux kernel -- at least at the most superficial layers. At the top level is the main makefile and a series of sub-directories identified below and discussed in the following paragraphs:</p> @@ -105,19 +142,834 @@ below and discussed in the following paragraphs:</p> </pre></ul> <h2>2.1 <a name="DirStructDocumentation">Documentation</a></h2> + +<p> + General documentation for the NuttX OS resides in this directory. +</p> + <h2>2.2 <a name="DirStructArch">arch</a></h2> + +<h3><a name="sudirectorystructure">2.2.1 Subdirectory Structure</a></h3> +<p> + This directory contains several sub-directories, each containing + architecture-specific logic. + The task of porting NuttX to a new processor or board consists of + add a new sudirectory under <code>arch/</code> containing logic specific + to the new architecuture. + Each architecture must provide a subdirectory, <<i>arch-name</i>> + under <code>arch/</code> with the folling characteristics: +</p> +<ul><pre> + <<i>arch-name</i>> + |-- Make.defs + |-- defconfig + |-- setenv.sh + |-- include + | |-- arch.h + | |-- irq.h + | `-- types.h + `-- src + |-- Makefile + `-- (architecture-specific source files) +</pre></ul> + +<h3><a name="summaryoffiles">2.2.2 Summary of Files</a></h3> +<ul> + <li> + <code>Make.defs</code>: 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: + <ul> + <li>Tools: CC, LD, AR, NM, OBJCOPY, OBJDUMP</li> + <li>Tool options: CFLAGS, LDFLAGS</li> + </ul> + <p> + 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. + </li> + <li> + <code>defconfig</code>: This is a configuration file similar to the Linux + configuration file. In contains varialble/value pairs like: + <ul> + <li><code>CONFIG_VARIABLE</code>=value</li> + </ul> + <p> + This configuration file will be used at build time: + </p> + <ol> + <li>As a makefile fragment included in other makefiles, and</li> + <li>to generate <code>include/nuttx/config.h</code> which is included by + most C files in the system.</li> + </ol> + </li> + <li> + <code>setenv.sh</code>: 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. + </li> + <li> + <code>include/arch.h</code>: + This is a hook for any architecture specific definitions that may + be needed by the system. It is included by <code>include/nuttx/arch.h</code>. + </li> + <li> + <code>include/types.h</code>: + This provides architecture/toolchain-specific definitions for + standard types. This file should <code>typedef</code>: + <ul><code> + sbyte, ubyte, uint8, boolean, sint16, uint16, sint32, uint32 + </code></ul> + <p>and if the architecture supports 64-bit integers</p> + <ul><code> + sint64, uint64 + </code></ul> + <p> + and finally + </p> + <ul><code> + irqstate_t + </code></ul> + <p> + Must be defined to the be the size required to hold the interrupt + enable/disable state. + </p> + <p> + This file will be included by include/sys/types.h and be made + available to all files. + </p> + </li> + <li> + <code>include/irq.h</code>: + This file needs to define some architecture specific functions (usually + inline if the compiler supports inlining) and structure. These include: + <ul> + <li> + <code>struct xcptcontext</code>: + This structures represents the saved context of a thread. + </li> + <li> + <code>irqstate_t irqsave(void)</code>: + Used to disable all interrupts. + </li> + <li> + <code>void irqrestore(irqstate_t flags)<code>: + Used to restore interrupt enables to the same state as before <code>irqsave()</code> was called. + </li> + </ul> + <p> + This file must also define <code>NR_IRQS</code>, the total number of IRQs supported + by the board. + </p> + </li> + <li> + <code>src/Makefile</code>: + This makefile will be executed to build the targets <code>src/libup.a</code> and + <code>src/up_head.o</code>. The <code>up_head.o</code> file holds the entry point into the system + (power-on reset entry point, for example). It will be used in + the final link with <code>libup.a</code> and other system archives to generate the + final executable. + </li> +</ul> + +<h3><a name="supportedarchitectures">2.2.3 Supported Architectures</a></h3> +<ul> + <li><code>arch/sim</code>: + A user-mode port of NuttX to the x86 Linux platform is available. + The purpose of this port is primarily to support OS feature developement. + This port does not support interrupts or a real timer (and hence no + round robin scheduler) Otherwise, it is complete. + <li><code>arch/c5471</code>: + TI TMS320C5471 (also called TMS320DM180 or just C5471). + 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 complete, verified, and included in the NuttX release. + <li><code>arch/dm320</code>: + TI TMS320DM320 (also called just DM320). + NuttX operates on the ARM9EJS of this dual core processor. + This port uses the Neuros OSD with a GNU arm-elf toolchain*: + see http://wiki.neurostechnology.com/index.php/Developer_Welcome . + STATUS: This port is code complete but totally untested due to + hardware issues with my OSD. + <li><code>arch/pjrc-8051</code>: + 8051 Microcontroller. This port uses the PJRC 87C52 development system + and the SDCC toolchain. This port is not quite ready for prime time. +</ul> +<p> + Other ports for the for the TI TMS320DM270 and for MIPS are in various states + of progress +</p> + +<h3><a name="configuringnuttx">2.2.4 Configuring NuttX</a></h3> +<p> + Configuring NuttX requires only copying: +</p> +<ul> + <code>arch/<<i>arch-name</i>>/Make.def</code> to <code>${TOPDIR}/Make.defs</code>, + <code>arch/<<i>arch-name</i>>/setenv.sh</code> to <code>${TOPDIR}/setenv.sh</code>, and + <code.arch/<<i>arch-name</i>>/defconfig</code> to ${TOPDIR}/.config</code> +</ul> +<p> + There is a script that automates these steps. The following steps will + accomplish the same configuration: +</p> +<ul><pre> + cd tools + ./configure.sh <<i>arch-name</i>> +</pre></ul> + <h2>2.3 <a name="DirStructDrivers">drivers</a></h2> + +<p> + This directory holds architecture-independent device drivers. +</p> + <h2>2.4 <a name="DirStructExamples">examples</a></h2> + +<p> + Example and test programs to build against. +</p> + <h2>2.5 <a name="DirStructFs">fs</a></h2> + +<p> + This directory contains the NuttX filesystem. + The NuttX filesystem is very simple; it does not involve any block drivers or + particular filesystem (like FAT or EXT2 etc.). + The NuttX filesystem simply supports a set a filesystem APIs + (<code>open()</code>, <code>close()</code>, <code>read()</code>, <code>write</code>, etc.) + and a registration mechanism that allows devices drivers to a associated with <i>nodes</i> + in a file-system-like name space. +</p> + <h2>2.6 <a name="DirStructInclude">include</a></h2> +<p> + This directory holds NuttX header files. + Standard header files file retained in can be included in the <i>normal</i> fashion: +</p> +<ul> + <code>include <:stdio.h></code><br> + <code>include <sys/types.h></code><br> + etc. +</ul> + <h2>2.7 <a name="DirStructLib">lib</a></h2> + +<p> + This directory holds a collection of standard libc-like functions with custom + interfaces into Nuttx. +</p> + <h2>2.8 <a name="DirStructMm">mm</a></h2> + +<p> + This is the NuttX memory manager. +</p> + <h2>2.9 <a name="DirStructSched">sched</a></h2> + +<p> + The files forming core of the NuttX RTOS reside here. +</p> + <h2>2.10 <a name="DirStructDrivers">tools</a></h2> +<p> + This directory holds a collection of tools and scripts to simplify + configuring and building NuttX. +</p> + <hr> <h1>3.0 <a name="DirectoryConfiAndBuild">Configuring and Building</a></h1> +<h1>4.0 <a name="ArchAPIs">Architecture APIs</a></h1> + +<p> + The file <code>include/nuttx/arch.h</code> identifies by prototype all of the APIs that must + be provided by the architecture specific logic. + The internal OS APIs that architecture-specific logic must + interface with also also identified in <code>include/nuttx/arch.h</code> or in + other header files. +</p> + +<h2><a name="imports">4.1 APIs Exported by Architecture-Specific Logic to NuttX</a></h2> +<h3><a name="upinitialize">4.1.1 <code>up_initialize()</code></a></h3> + +<p><b>Prototype</b>: <code>void up_initialize(void);</code></p> + +<p><b>Description</b>. + <code>up_initialize()</code> will be called once during OS + initialization after the basic OS services have been + initialized. The architecture specific details of + initializing the OS will be handled here. Such things as + setting up interrupt service routines, starting the + clock, and registering device drivers are some of the + things that are different for each processor and hardware + platform. +</p> +<p> + <code>up_initialize()</code> is called after the OS initialized but + before the init process has been started and before the + libraries have been initialized. OS services and driver + services are available. +</p> + +<h3><a name="upidle">4.1.2 <code>up_idle()</code></a></h3> +<p><b>Prototype</b>: <code>void up_idle(void);</code></p> + +<p><b>Description</b>. + <code>up_idle()</code> is the logic that will be executed + when their is no other ready-to-run task. This is processor + idle time and will continue until some interrupt occurs to + cause a context switch from the idle task. +</p> +<p> + Processing in this state may be processor-specific. e.g., + this is where power management operations might be performed. +</p> + +<h3><a name="upinitialstate">4.1.3 <code>up_initial_state()</code></a></h3> +<p><b>Prototype</b>: <code>void up_initial_state(FAR _TCB *tcb);</code></p> + +<p><b>Description</b>. + A new thread is being started and a new TCB + has been created. This function is called to initialize + the processor specific portions of the new TCB. +</p> +<p> + This function must setup the intial architecture registers + and/or stack so that execution will begin at tcb->start + on the next context switch. +</p> + +<h3><a name="upcreatestack">4.1.4 <code>up_create_stack()</code></a></h3> +<p><b>Prototype</b>: <code>STATUS up_create_stack(FAR _TCB *tcb, size_t stack_size);</code></p> + +<p><b>Description</b>. + Allocate a stack for a new thread and setup + up stack-related information in the TCB. +</p> +<p> + The following TCB fields must be initialized: +</p> +<ul> + <li><code>adj_stack_size</code>: Stack size after adjustment for hardware, + processor, etc. This value is retained only for debug + purposes.</li> + <li><code>stack_alloc_ptr</code>: Pointer to allocated stack</li> + <li><code>adj_stack_ptr</code>: Adjusted <code>stack_alloc_ptr</code> for HW. The + initial value of the stack pointer. +</ul> +<p> + This API is <i>NOT</i> required if <code>CONFIG_CUSTOM_STACK</code> + is defined. +</p> + +<p><b>Inputs</b>:</p? +<ul> + <li> + <code>tcb</code>: The TCB of new task. + </li> + <li> + <code>stack_size</code>: The requested stack size. At least this much + must be allocated. + </li> +</ul> + +<h3><a name="upusestack">4.1.5 <code>up_use_stack()</code></a></h3> +<p><b>Prototype</b>: + <code>STATUS up_use_stack(FAR _TCB *tcb, FAR void *stack, size_t stack_size);</code> +</p> + +<p><b>Description</b>. + Setup up stack-related information in the TCB + using pre-allocated stack memory. +</p> +<p> + The following TCB fields must be initialized: +</p> +<ul> + <li><code>adj_stack_size</code>: Stack size after adjustment for hardware, + processor, etc. This value is retained only for debug + purposes.</li> + <li><code>stack_alloc_ptr</code>: Pointer to allocated stack</li> + <li><code>adj_stack_ptr</code>: Adjusted <code>stack_alloc_ptr</code> for HW. The + initial value of the stack pointer. +</ul> +<p> + This API is <i>NOT</i> required if <code>CONFIG_CUSTOM_STACK</code> + is defined. +</p> + +<p><b>Inputs:</b></p> +<ul> + <li> + <code>tcb</code>: The TCB of new task. + </li> + <li> + <code>stack_size</code>: The allocated stack size. + </li> +</ul> + +<h3><a name="upreleasestack">4.1.6 <code>up_release_stack()</code></a></h3> +<p><b>Prototype</b>: <code>void up_release_stack(FAR _TCB *dtcb);</code></p> + +<p><b>Description</b>. + A task has been stopped. Free all stack + related resources retained int the defunct TCB. +</p> +<p> + This API is <i>NOT</i> required if <code>CONFIG_CUSTOM_STACK</code> + is defined. +</p> + +<h3><a name="upunblocktask">4.1.7 <code>up_unblock_task()</code></a></h3> +<p><b>Prototype</b>: <code>void up_unblock_task(FAR _TCB *tcb);</code></p> + +<p><b>Description</b>. + A task is currently in an inactive task list + but has been prepped to execute. Move the TCB to the + ready-to-run list, restore its context, and start execution. +</p> +<p> + This function is called only from the NuttX scheduling + logic. Interrupts will always be disabled when this + function is called. +</p> + +<p><b>Inputs</b>: +<ul> + <li><code>tcb</code>: Refers to the tcb to be unblocked. This tcb is + in one of the waiting tasks lists. It must be moved to + the ready-to-run list and, if it is the highest priority + ready to run taks, executed. + </li> +</ul> + +<h3><a name="upblocktask">4.1.8 <code>up_block_task()</code></a></h3> +<p><b>Prototype</b>: <code>void up_block_task(FAR _TCB *tcb, tstate_t task_state);</code></p> + +<p><b>Description</b>. + The currently executing task at the head of + the ready to run list must be stopped. Save its context + and move it to the inactive list specified by task_state. + + This function is called only from the NuttX scheduling + logic. Interrupts will always be disabled when this + function is called. + +<p><b>Inputs:</b></p> +<ul> + <li><code>tcb</code>: Refers to a task in the ready-to-run list (normally + the task at the the head of the list). It most be + stopped, its context saved and moved into one of the + waiting task lists. It it was the task at the head + of the ready-to-run list, then a context to the new + ready to run task must be performed. + </li> + <li><code>task_state</code>: Specifies which waiting task list should be + hold the blocked task TCB. + </li> +</ul> + +<h3><a name="upreleasepending">4.1.9 <code>up_release_pending()</code></a></h3> +<p><b>Prototype</b>: <code>void up_release_pending(void);</code></p> + +<p><b>Description</b>. + When tasks become ready-to-run but cannot run because pre-emption + is disabled, they are placed into a pending task list. + This function releases and makes ready-to-run all of the tasks that have + collected in the pending task list. This can cause a + context switch if a new task is placed at the head of + the ready to run list. +</p> +<p> + This function is called only from the NuttX scheduling logic when + pre-emption is re-enabled. Interrupts will always be disabled when this + function is called. +</p> + +<h3><a name="upreprioritizertr">4.1.10 <code>up_reprioritize_rtr()</code></a></h3> +<p><b>Prototype</b>: <code>void up_reprioritize_rtr(FAR _TCB *tcb, ubyte priority);</code></p> + +<p><b>Description</b>. + Called when the priority of a running or + ready-to-run task changes and the reprioritization will + cause a context switch. Two cases: +</p> +<ol> + <li> + The priority of the currently running task drops and the next + task in the ready to run list has priority. + </li> + <li> + An idle, ready to run task's priority has been raised above the + the priority of the current, running task and it now has the + priority. + </li> +</ol> +<p> + This function is called only from the NuttX scheduling + logic. Interrupts will always be disabled when this + function is called. +</p> + +<p><b>Inputs:</b></p> +<ul> + <li> + <code>tcb</code>: The TCB of the task that has been reprioritized + </li> + <li> + <code>priority</code>: The new task priority + </li> +</ul> + +<h3><a name="_exit">4.1.11 <code>_exit()</code></a></h3> +<p><b>Prototype</b>: <code>void _exit(int status) noreturn_function;</code></p> + +<p><b>Description</b>. + This function causes the currently executing task to cease + to exist. This is a special case of task_delete(). +</p> +<p> + Unlike other UP APIs, this function may be called + directly from user programs in various states. The + implementation of this function should diable interrupts + before performing scheduling operations. +</p> + +<h3><a name="upassert">4.1.12 <code>up_assert()</code></a></h3> +<p><b>Prototype</b>:<br> + <code>void up_assert(FAR const ubyte *filename, int linenum);</code></br> + <code>void up_assert_code(FAR const ubyte *filename, int linenum, int error_code);</code></br> +</p> + +<p><b>Description</b>. + Assertions may be handled in an architecture-specific + way. +</p> + +<h3><a name="upschedulesigaction">4.1.13 <code>up_schedule_sigaction()</code></a></h3> +<p><b>Prototype</b>: + <code>void up_schedule_sigaction(FAR _TCB *tcb, sig_deliver_t sigdeliver);</code> +</p> + +<p><b>Description</b>. + This function is called by the OS when one or more + signal handling actions have been queued for execution. + The architecture specific code must configure things so + that the 'igdeliver' callback is executed on the thread + specified by 'tcb' as soon as possible. +</p> +<p> + This function may be called from interrupt handling logic. +</p> +<p> + This operation should not cause the task to be unblocked + nor should it cause any immediate execution of sigdeliver. + Typically, a few cases need to be considered: +</p> +<ol> + <li> + This function may be called from an interrupt handler + During interrupt processing, all xcptcontext structures + should be valid for all tasks. That structure should + be modified to invoke sigdeliver() either on return + from (this) interrupt or on some subsequent context + switch to the recipient task. + </li> + <li> + If not in an interrupt handler and the tcb is NOT + the currently executing task, then again just modify + the saved xcptcontext structure for the recipient + task so it will invoke sigdeliver when that task is + later resumed. + </li> + <li> + If not in an interrupt handler and the tcb IS the + currently executing task -- just call the signal + handler now. + </li> +</ol> +<p> + This API is <i>NOT</i> required if <code>CONFIG_DISABLE_SIGNALS</code> + is defined. +</p> + +<h3><a name="upallocateheap">4.1.14 <code>up_allocate_heap()</code></a></h3> +<p><b>Prototype</b>: <code>void up_allocate_heap(FAR void **heap_start, size_t *heap_size);</code></p> + +<p><b>Description</b>. + The heap may be statically allocated by + defining CONFIG_HEAP_BASE and CONFIG_HEAP_SIZE. If these + are not defined, then this function will be called to + dynamically set aside the heap region. +</p> +<p> + This API is <i>NOT</i> required if <code>CONFIG_HEAP_BASE</code> + is defined. +</p> + +<h3><a name="upinterruptcontext">4.1.15 <code>up_interrupt_context()</code></a></h3> +<p><b>Prototype</b>: <code>boolean up_interrupt_context(void)</code></p> + +<p><b>Description</b>. + Return TRUE is we are currently executing in + the interrupt handler context. +</p> + +<h3><a name="updisableirq">4.1.16 <code>up_disable_irq()</code></a></h3> +<p><b>Prototype</b>: <code>void up_disable_irq(int irq);</code></p> + +<p><b>Description</b>. + Disable the IRQ specified by 'irq' +</p> + +<h3><a name="upenableirq">4.1.17 <code>up_enable_irq()</code></a></h3> +<p><b>Prototype</b>: <code>void up_enable_irq(int irq);</code></p> + +<p><b>Description</b>. + Enable the IRQ specified by 'irq' +</p> + +<h3><a name="upputc">4.1.18 <code>up_putc()</code></a></h3> + +<p><b>Prototype</b>: <code>int up_putc(int ch);</code></p> +<p><b>Description</b>. + This is a debug interface exported by the architecture-specific logic. + Output one character on the console +<p> + This API is <i>NOT</i> required if <code>CONFIG_HEAP_BASE</code> + is defined. +</p> + +<h2><a name="exports">4.2 APIs Exported by NuttX to Architecture-Specific Logic</a></h2> +<p> + These are standard interfaces that are exported by the OS + for use by the architecture specific logic. +</p> + +<h3><a name="osstart">4.2.1 <code>os_start()</code></a></h3> +<p> + <b><i>To be provided</i></b> +</p> + +<h3><a name="listmgmt">4.2.2 OS List Management APIs</a></h3></h3> +<p> + <b><i>To be provided</i></b> +</p> + +<h3><a name="schedprocesstimer">4.2.3 <code>sched_process_timer()</code></a></h3> +<p><b>Prototype</b>: <code>void sched_process_timer(void);</code></p> + +<p><b>Description</b>. + This function handles system timer events. + The timer interrupt logic itself is implemented in the + architecture specific code, but must call the following OS + function periodically -- the calling interval must be + <code>MSEC_PER_TICK</code>. +</p> + +<h3><a name="irqdispatch">4.2.4 <code>irq_dispatch()</code></a></h3> +<p><b>Prototype</b>: <code>void irq_dispatch(int irq, FAR void *context);</code></p> + +<p><b>Description</b>. + This function must be called from the achitecture- + specific logic in order to dispaly an interrupt to + the appropriate, registered handling logic. +</p> + +<h1><a name="apndxconfigs">Appendix A: NuttX Configuration Settings</a></h1> + +<p> + The following variables are recognized by the build (you may + also include architecture-specific settings). +</p> + +<h2>Architecture selection</h2> + +<ul> + <li><code>CONFIG_ARCH</code>: identifies the arch subdirectory + <li><code>CONFIG_ARCH_name</code>: for use in C code +</ul> + +<h2>General OS setup</h2> + +<ul> + <li> + <code>CONFIG_EXAMPLE</code>: identifies the subdirectory in examples + that will be used in the build. + </li> + <li> + <code>CONFIG_DEBUG</code>: enables built-in debug options + </li> + <li> + <code>CONFIG_DEBUG_VERBOSE</code>: enables verbose debug output + </li> + <li> + <code>CONFIG_HAVE_LOWPUTC</code>: architecture supports low-level, boot + time console output + </li> + <li> + <code>CONFIG_MM_REGIONS</code>: 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); + </li> + <li> + <code>CONFIG_RR_INTERVAL</code>: The round robin timeslice will be set + this number of milliseconds; Round robin scheduling can + be disabled by setting this value to zero. + </li> + <li> + <code>CONFIG_SCHED_INSTRUMENTATION</code>: enables instrumentation in + scheduler to monitor system performance + </li> + <li> + <code>CONFIG_TASK_NAME_SIZE</code>: Spcifies that maximum size of a + task name to save in the TCB. Useful if scheduler + instrumentation is selected. Set to zero to disable. + </li> + <li> + <code>CONFIG_START_YEAR, CONFIG_START_MONTH, CONFIG_START_DAY - + Used to initialize the internal time logic. + </li> + <li> + <code>CONFIG_JULIAN_TIME</code>: Enables Julian time conversions + </li> + <li> + <code>CONFIG_DEV_CONSOLE</code>: Set if architecture-specific logic + provides /dev/console. Enables stdout, stderr, stdin. + </li> +</ul> + +<p> + 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. +</p> +<p> + There are certain dependency relationships in these features. +</p> +<ul> + <li> + <code>mq_notify()</code> logic depends on signals to awaken tasks + waiting for queues to become full or empty. + </li> + <li> + <code>pthread_condtimedwait()</code> depends on signals to wake + up waiting tasks. + </li> +</ul> + +<ul> + <code>CONFIG_DISABLE_CLOCK</code>, <code>CONFIG_DISABLE_PTHREAD</code>, + <code>CONFIG_DISABLE_SIGNALS</code>, <code>CONFIG_DISABLE_MQUEUE</code>, +</ul> + +<h2>Miscellaneous libc settings</h2> + +<ul> + <li> + <code>CONFIG_NOPRINTF_FIELDWIDTH</code>: sprintf-related logic is a + little smaller if we do not support fieldwidthes + </li> +</ul> + +<h2>Allow for architecture optimized implementations</h2> + +<p> + The architecture can provide optimized versions of the + following to improve sysem performance. +</p> + +<ul> +<p> + <code>CONFIG_ARCH_MEMCPY</code>, <code>CONFIG_ARCH_MEMCMP</code>, <code>CONFIG_ARCH_MEMMOVE</code>, + <code>CONFIG_ARCH_MEMSET</code>, <code>CONFIG_ARCH_STRCMP</code>, <code>CONFIG_ARCH_STRCPY</code>, + <code>CONFIG_ARCH_STRNCPY</code>, <code>CONFIG_ARCH_STRLEN</code>, <code>CONFIG_ARCH_BZERO</code>, + <code>CONFIG_ARCH_KMALLOC</code>, <code>CONFIG_ARCH_KZMALLOC</code>, <code>ONFIG_ARCH_KFREE</code>, +</p> +</ul> + +<h2>Sizes of configurable things (0 disables)</h2> + +<ul> + <li> + <code>CONFIG_MAX_TASKS</code>: The maximum number of simultaneously + active tasks. This value must be a power of two. + </li> + <li> + <code>CONFIG_NPTHREAD_KEYS</code>: The number of items of thread- + specific data that can be retained + </li> + <li> + <code>CONFIG_NFILE_DESCRIPTORS</code>: The maximum number of file + descriptors (one for each open) + </li> + <li> + <code>CONFIG_NFILE_STREAMS</code>: The maximum number of streams that + can be fopen'ed + </li> + <li> + <code>CONFIG_NAME_MAX</code>: The maximum size of a file name. + </li> + <li> + <code>CONFIG_STDIO_BUFFER_SIZE</code>: Size of the buffer to allocate + on fopen. (Only if CONFIG_NFILE_STREAMS > 0) + </li> + <li> + <code>CONFIG_NUNGET_CHARS</code>: Number of characters that can be + buffered by ungetc() (Only if CONFIG_NFILE_STREAMS > 0) + </li> + <li> + <code>CONFIG_PREALLOC_MQ_MSGS</code>: The number of pre-allocated message + structures. The system manages a pool of preallocated + message structures to minimize dynamic allocations + </li> + <li> + <code>CONFIG_MQ_MAXMSGSIZE</code>: Message structures are allocated with + a fixed payload size given by this settin (does not include + other message structure overhead. + </li> + <li> + <code>CONFIG_PREALLOC_WDOGS</code>: The number of pre-allocated watchdog + structures. The system manages a pool of preallocated + watchdog structures to minimize dynamic allocations + </li> +</ul> + +<h2>Stack and heap information</h2> + +<ul> + <li> + <code>CONFIG_BOOT_FROM_FLASH</code>: Some configurations support XIP + operation from FLASH. + </li> + <li> + <code>CONFIG_STACK_POINTER</code>: The initial stack pointer + </li> + <li> + <code>CONFIG_PROC_STACK_SIZE</code>: The size of the initial stack + </li> + <li> + <code>CONFIG_PTHREAD_STACK_MIN</code>: Minimum pthread stack size + </li> + <li> + <code>CONFIG_PTHREAD_STACK_DEFAULT</code>: Default pthread stack size + </li> + <li> + <code>CONFIG_HEAP_BASE</code>: The beginning of the heap + </li> + <li> + <code>CONFIG_HEAP_SIZE</code>: The size of the heap + </li> +</ul> + </body> </html> |