NuttxPortingGuide.html

<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>
<p>
  The following configuration itemes select the architecture, chip, and
  board configuration for the build.
</p>
<ul>
  <li><code>CONFIG_ARCH</code>:
    Identifies the arch subdirectory</li>
  <li><code>CONFIG_ARCH_name</code>:
    For use in C code</li>
  <li><code>CONFIG_ARCH_CHIP</code>:
    Identifies the arch/*/chip subdirectory</li>
  <li><code>CONFIG_ARCH_CHIP_name</code>:
    For use in C code</li>
  <li><code>CONFIG_ARCH_BOARD</code>:
     Identifies the configs subdirectory and hence, the board that supports
     the particular chip or SoC.</li>
  <li><code>CONFIG_ARCH_BOARD_name</code>:
     For use in C code</li>
</ul>

<p>
  Some architectures require a description of the the RAM configuration:
</p>
<ul>
  <li><code>CONFIG_DRAM_SIZE</code>:
    Describes the installed DRAM.</li>
  <li><code>CONFIG_DRAM_START</code>:
    The start address of DRAM (physical)</li>
  <li><code>CONFIG_DRAM_VSTART</code>:
    The startaddress of DRAM (virtual)</li>
</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>CONFI_DISABLE_POSIX_TIMERS</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>

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