diff --git a/ChangeLog b/ChangeLog
index 614381c900ad8d367eebbcf144cbd70227348009..107a426d6f296f0224e271cfd8fc57855f13f7eb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -816,7 +816,7 @@
and (2) it requires symbol table arguments.
* lib/: Add fileno()
* examples/ostest: Several of the tests used a big, hard-coded stack size
- when creating test threads (16Kb stacksize). The stack size should
+ when creating test threads (16K stacksize). The stack size should
be controlled by the .config file or the OSTest won't work on platforms
with memory constraints.
* netutils/thttpd: An initial port of Jeff Poskanzer's THTTPD HTTP server.
@@ -1369,10 +1369,10 @@
out instead. This improves behavior, for example, on the first GET request
from a browser.
* arch/arm/src/lpc17xx/lpc17_emacram.h and lpc17_allocateheap.c: The Ethernet
- logic was using all of AHB SRAM Bank0 for Ethernet packet buffers (16Kb). An
+ logic was using all of AHB SRAM Bank0 for Ethernet packet buffers (16K). An
option was added to limit the amount of SRAM used for packet buffering and to
re-use any extra Bank0 memory for heap. configs/olimex-lpc1766stk/nettest
- now uses only 8Kb at the beginning of Bank0; the 8Kb at the end of Bank0 is
+ now uses only 8K at the beginning of Bank0; the 8K at the end of Bank0 is
included in the heap
* arch/arm/src/lpc17xx/lpc17_ssp.c: Fix compilation errors when SSP1 is
selected.
@@ -1785,7 +1785,7 @@
that support 16-bit addressability have smaller overhead than devices
that support 32-bit addressability. However, there are many MCUs
that support 32-bit addressability *but* have internal SRAM of size
- less than or equal to 64Kb. In this case, CONFIG_MM_SMALL can be
+ less than or equal to 64K. In this case, CONFIG_MM_SMALL can be
defined so that those MCUs will also benefit from the smaller, 16-
bit-based allocation overhead.
* lib/string/lib_strndup.c: Add standard strndup() library function.
@@ -1846,7 +1846,7 @@
* arch/sim/src/up_romgetc.c: Used to test the basic logic to access strings
without directly de-referencing a string pointer.
* arch/avr/src/avr/up_romget.c: Used to access strings that lie in the first
- 64Kb of FLASH (But I still haven't figured out how to get strings to reside in
+ 64K of FLASH (But I still haven't figured out how to get strings to reside in
FLASH without using the PROGMEM attribute).
* configs/teensy/src/up_spi.c: Correct reading of SD CD and WP pins (was reading
the wrong register. AVR SPI now appears to be functional.
diff --git a/Documentation/NuttShell.html b/Documentation/NuttShell.html
index a92cbadd8e62e86955a56857f3935935df109ebc..ca7e82627966b5679d4f303d16b2e4283d596969 100644
--- a/Documentation/NuttShell.html
+++ b/Documentation/NuttShell.html
@@ -8,7 +8,7 @@
<tr align="center" bgcolor="#e4e4e4">
<td>
<h1><big><font color="#3c34ec"><i>NuttShell (NSH)</i></font></big></h1>
- <p>Last Updated: August 3, 2012</p>
+ <p>Last Updated: August 7, 2012</p>
</td>
</tr>
</table>
@@ -1210,7 +1210,7 @@ losetup [-o <offset>] [-r] <dev-path> <file-path>
<p>
<b>Synopsis</b>.
Setup the loop device at <dev-path> to access the file at <file-path> as a block device.
- In the following example a 256Kb file is created (<code>dd</code>) and <code>losetup</code> is
+ In the following example a 256K file is created (<code>dd</code>) and <code>losetup</code> is
used to make the file accessible as a block device.
A FAT file system is created (<code>mkfatfs</code>) and mounted (<code>mount</code>).
Files can then be managed on the loop-mounted file.
@@ -3148,7 +3148,7 @@ endef
</p>
<li>
<p>
- The make file then defines the application name (<code>hello</code>), the task priority (default), and the stack size that will be allocated in the task runs (2Kb).
+ The make file then defines the application name (<code>hello</code>), the task priority (default), and the stack size that will be allocated in the task runs (2K).
</p>
<ul><pre>
APPNAME = hello
@@ -3160,7 +3160,7 @@ STACKSIZE = 2048
<p>
And finally, the <code>Makefile</code> invokes the <code>REGISTER</code> macro to added the <code>hello_main()</code> named application.
Then, when the system build completes, the <code>hello</code> command can be executed from the NSH command line.
- When the <code>hello</code> command is executed, it will start the task with entry point <code>hello_main()</code> with the default priority and with a stack size of 2Kb.
+ When the <code>hello</code> command is executed, it will start the task with entry point <code>hello_main()</code> with the default priority and with a stack size of 2K.
</p>
<ul><pre>
.context:
diff --git a/Documentation/NuttX.html b/Documentation/NuttX.html
index ed994d69b9c0ba0cea00d695dcd112de014889a6..b7026f89651d494a415802051d0e42b1a4523b5e 100644
--- a/Documentation/NuttX.html
+++ b/Documentation/NuttX.html
@@ -858,9 +858,9 @@
<p>
Using a variety of technologies, NuttX can scale from the very tiny to
the moderate-size system. I have executed NuttX with some simple applications
- in as little as 32Kb <i>total</i> memory (code and data).
- On the other hand, typical, richly featured NuttX builds require more like 64Kb
- (and if all of the features are used, this can push 100Kb).
+ in as little as 32K <i>total</i> memory (code and data).
+ On the other hand, typical, richly featured NuttX builds require more like 64K
+ (and if all of the features are used, this can push 100K).
</p>
</td>
</tr>
@@ -2028,8 +2028,8 @@
<b>Micropendous 3 AT9USB64x</b> and <b>AT9USB6128x</b>.
This port of NuttX to the Opendous Micropendous 3 board. The Micropendous3 is
may be populated with an AT90USB646, 647, 1286, or 1287. I have only the AT90USB647
- version for testing. This version have very limited memory resources: 64Kb of
- FLASH and 4Kb of SRAM.
+ version for testing. This version have very limited memory resources: 64K of
+ FLASH and 4K of SRAM.
</p>
<ul>
<p>
@@ -2085,7 +2085,7 @@
</p>
<p>
Most NuttX test applications are console-oriented with lots of strings used for printf and debug output.
- These strings are all stored in SRAM now due to these data accessing issues and even the smallest console-oriented applications can quickly fill a 4-8Kb memory.
+ These strings are all stored in SRAM now due to these data accessing issues and even the smallest console-oriented applications can quickly fill a 4-8K memory.
So, in order for the AVR port to be useful, one of two things would need to be done:
</p>
<ol>
@@ -2917,7 +2917,7 @@ if [ -x "$WINELOADER" ]; then exec "$WINELOADER" "$appname" "$@"; fi
</pre>
<p><b>87C52</b>
A reduced functionality OS test for the 8052 target requires only
- about 18-19Kb:
+ about 18-19K:
</p>
<pre>
Stack starts at: 0x21 (sp set to 0x20) with 223 bytes available.
diff --git a/Documentation/NuttXDemandPaging.html b/Documentation/NuttXDemandPaging.html
index 3246e070d0f418f46f98c9ff19dbd50a343f35e1..c238161a8257242a6184d44a4c2008cecffe6d0a 100644
--- a/Documentation/NuttXDemandPaging.html
+++ b/Documentation/NuttXDemandPaging.html
@@ -1,675 +1,675 @@
-<html>
-<head>
-<title>On-Demand Paging</title>
-</head>
-<body background="backgd.gif">
-<hr><hr>
-<table width ="100%">
- <tr align="center" bgcolor="#e4e4e4">
- <td>
- <h1><big><font color="#3c34ec"><i>On-Demand Paging</i></font></big></h1>
- <h2><font color="#dc143c">>>> Under Construction <<<</font></h2>
- <p>Last Updated: August 12, 2010</p>
- </td>
- </tr>
-</table>
-<hr><hr>
-
-<table width ="100%">
- <tr bgcolor="#e4e4e4">
- <td>
- <h1>Table of Contents</h1>
- </td>
- </tr>
-</table>
-
-<center><table width ="80%">
-<tr>
- <td>
- <table>
- <tr>
- <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
- <td>
- <a href="#Introduction">Introduction</a>
- </td>
- </tr>
- <tr>
- <td> </td>
- <td>
- <a href="#Overview">Overview</a>
- </td>
- </tr>
- <tr>
- <td> </td>
- <td>
- <a href="#Terminology">Terminology</a>
- </td>
- </tr>
- </table>
- </td>
-</tr>
-<tr>
- <td>
- <table>
- <tr>
- <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
- <td>
- <a href="#NuttXDesign">NuttX Common Logic Design Description</a>
- </td>
- </tr>
- <tr>
- <td> </td>
- <td>
- <a href="#Initialization">Initialization</a>
- </td>
- </tr>
- <tr>
- <td> </td>
- <td>
- <a href="#PageFaults">Page Faults</a>
- </td>
- </tr>
- <tr>
- <td> </td>
- <td>
- <a href="#FillInitiation">Fill Initiation</a>
- </td>
- </tr>
- <tr>
- <td> </td>
- <td>
- <a href="#FillComplete">Fill Complete</a>
- </td>
- </tr>
- <tr>
- <td> </td>
- <td>
- <a href="#TaskResumption">Task Resumption</a>
- </td>
- </tr>
- </table>
- </td>
-</tr>
-<tr>
- <td>
- <table>
- <tr>
- <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
- <td>
- <a href="#ArchSupport">Architecture-Specific Support Requirements</a>
- </td>
- </tr>
- <tr>
- <td> </td>
- <td>
- <a href="#MemoryOrg">Memory Organization</a>
- </td>
- </tr>
- <tr>
- <td> </td>
- <td>
- <a href="#ArchFuncs">Architecture-Specific Functions</a>
- </td>
- </tr>
- </table>
- </td>
-</tr>
-
-</table></center>
-
-<table width ="100%">
- <tr bgcolor="#e4e4e4">
- <td>
- <a name="Introduction"><h1>Introduction</h1></a>
- </td>
- </tr>
-</table>
-<a name="Overview"><h2>Overview</h2></a>
-
-<p>
- This document summarizes the design of NuttX on-demand paging.
- This feature permits embedded MCUs with some limited RAM space to execute large programs from some non-random access media.
- This feature was first discussed in this email thread:
- <a href="http://tech.groups.yahoo.com/group/nuttx/message/213">http://tech.groups.yahoo.com/group/nuttx/message/213</a>.
-</p>
-<p>
- What kind of platforms can support NuttX on-demang paging?
- <ol>
- <li>
- The MCU should have some large, probably low-cost non-volatile storage such as serial FLASH or an SD card.
- This storage probably does not support non-random access (otherwise, why not just execute the program directly on the storage media).
- SD and serial FLASH are inexpensive and do not require very many pins and SPI support is prevalent in just about all MCUs.
- This large serial FLASH would contain a big program. Perhaps a program of several megabytes in size.
- </li>
- <li>
- The MCU must have a (relatively) small block of fast SRAM from which it can execute code.
- A size of, say 256Kb (or 192Kb as in the NXP LPC3131) would be sufficient for many applications.
- </li>
- <li>
- The MCU has an MMU (again like the NXP LPC3131).
- </li>
- </ol>
-</p>
-<p>
- If the platform meets these requirement, then NuttX can provide on-demand paging:
- It can copy .text from the large program in non-volatile media into RAM as needed to execute a huge program from the small RAM.
-</p>
-
-<a name="Terminology"><h2>Terminology</h2></a>
-
-<dl>
- <dt><code>g_waitingforfill</code></dt>
- <dd>An OS list that is used to hold the TCBs of tasks that are waiting for a page fill.</dd>
- <dt><code>g_pftcb</code></dt>
- <dd>A variable that holds a reference to the TCB of the thread that is currently be re-filled.</dd>
- <dt><code>g_pgworker</code></dt>
- <dd>The <i>process</i> ID of of the thread that will perform the page fills.</dd>
- <dt><code>pg_callback()</code></dt>
- <dd>The callback function that is invoked from a driver when the fill is complete.</dd>
- <dt><code>pg_miss()</code></dt>
- <dd>The function that is called from architecture-specific code to handle a page fault.</dd>
- <dt><code>TCB</code></dt>
- <dd>Task Control Block</dd>
-</dl>
-
-<table width ="100%">
- <tr bgcolor="#e4e4e4">
- <td>
- <a name="NuttXDesign"><h1>NuttX Common Logic Design Description</h1></a>
- </td>
- </tr>
-</table>
-
-
-<a name="Initialization"><h2>Initialization</h2></a>
-
-<p>
- The following declarations will be added.
- <ul>
- <li>
- <b><code>g_waitingforfill</code></b>.
- A doubly linked list that will be used to implement a prioritized list of the TCBs of tasks that are waiting for a page fill.
- </li>
- <li>
- <b><code>g_pgworker</code></b>.
- The <i>process</i> ID of of the thread that will perform the page fills
- </li>
- </ul>
-</p>
-<p>
- During OS initialization in <code>sched/os_start.c</code>, the following steps
- will be performed:
- <ul>
- <li>
- The <code>g_waitingforfill</code> queue will be initialized.
- </li>
- <li>
- The special, page fill worker thread, will be started.
- The <code>pid</code> of the page will worker thread will be saved in <code>g_pgworker</code>.
- Note that we need a special worker thread to perform fills;
- we cannot use the "generic" worker thread facility because we cannot be
- assured that all actions called by that worker thread will always be resident in memory.
- </li>
- </ul>
- </p>
- <p>
- Declarations for <code>g_waitingforfill</code>, <code>g_pgworker</code>, and other
- internal, private definitions will be provided in <code>sched/pg_internal.h</code>.
- All public definitions that should be used by the architecture-specific code will be available
- in <code>include/nuttx/page.h</code>.
- Most architecture-specific functions are declared in <code>include/nuttx/arch.h</code>,
- but for the case of this paging logic, those architecture specific functions are instead declared in <code>include/nuttx/page.h</code>.
- </p>
-
-<a name="PageFaults"><h2>Page Faults</h2></a>
-
-<p>
- <b>Page fault exception handling</b>.
- Page fault handling is performed by the function <code>pg_miss()</code>.
- This function is called from architecture-specific memory segmentation
- fault handling logic. This function will perform the following
- operations:
- <ol>
- <li>
- <b>Sanity checking</b>.
- This function will ASSERT if the currently executing task is the page fill worker thread.
- The page fill worker thread is how the the page fault is resolved and all logic associated with the page fill worker
- must be "<a href="#MemoryOrg">locked</a>" and always present in memory.
- </li>
- <li>
- <b>Block the currently executing task</b>.
- This function will call <code>up_block_task()</code> to block the task at the head of the ready-to-run list.
- This should cause an interrupt level context switch to the next highest priority task.
- The blocked task will be marked with state <code>TSTATE_WAIT_PAGEFILL</code> and will be retained in the <code>g_waitingforfill</code> prioritized task list.
- </li>
- <li>
- <b>Boost the page fill worker thread priority</b>.
- Check the priority of the task at the head of the <code>g_waitingforfill</code> list.
- If the priority of that task is higher than the current priority of the page fill worker thread, then boost the priority of the page fill worker thread to that priority.
- Thus, the page fill worker thread will always run at the priority of the highest priority task that is waiting for a fill.
- </li>
- <li>
- <b>Signal the page fill worker thread</b>.
- Is there a page already being filled?
- If not then signal the page fill worker thread to start working on the queued page fill requests.
- </li>
- </ol>
-</p>
-<p>
- When signaled from <code>pg_miss()</code>, the page fill worker thread will be awakenend and will initiate the fill operation.
-</p>
-<p>
- <b>Input Parameters.</b>
- None -- The head of the ready-to-run list is assumed to be that task that caused the exception.
- The current task context should already be saved in the TCB of that task.
- No additional inputs are required.
-</p>
-<p>
- <b>Assumptions</b>.
- <ul>
- <li>
- It is assumed that this function is called from the level of an exception handler and that all interrupts are disabled.
- </li>
- <li>
- The <code>pg_miss()</code> must be "<a href="#MemoryOrg">locked</a>" in memory.
- Calling <code>pg_miss()</code> cannot cause a nested page fault.
- </li>
- <li>
- It is assumed that currently executing task (the one at the head of the ready-to-run list) is the one that cause the fault.
- This will always be true unless the page fault occurred in an interrupt handler.
- Interrupt handling logic must always be available and "<a href="#MemoryOrg">locked</a>" into memory so that page faults never come from interrupt handling.
- </li>
- <li>
- The architecture-specific page fault exception handling has already verified that the exception did not occur from interrupt/exception handling logic.
- </li>
- <li>
- As mentioned above, the task causing the page fault must not be the page fill worker thread because that is the only way to complete the page fill.
- </li>
- </ul>
-</p>
-
-<a name="FillInitiation"><h2>Fill Initiation</h2></a>
-
-<p>
- The page fill worker thread will be awakened on one of three conditions:
- <ul>
- <li>
- When signaled by <code>pg_miss()</code>, the page fill worker thread will be awakenend (see above),
- </li>
- <li>
- From <code>pg_callback()</code> after completing last fill (when <code>CONFIG_PAGING_BLOCKINGFILL</code> is defined... see below), or
- </li>
- <li>
- A configurable timeout expires with no activity.
- This timeout can be used to detect failure conditions such things as fills that never complete.
- </li>
- </ul>
-</p>
-
-<p>
- The page fill worker thread will maintain a static variable called <code>_TCB *g_pftcb</code>.
- If no fill is in progress, <code>g_pftcb</code> will be NULL.
- Otherwise, it will point to the TCB of the task which is receiving the fill that is in progess.
-</p>
-<ul><small>
- <b>NOTE</b>:
- I think that this is the only state in which a TCB does not reside in some list.
- Here is it in limbo, outside of the normally queuing while the page file is in progress.
- While here, it will be marked with TSTATE_TASK_INVALID.
-</small></ul>
-
-<p>
- When awakened from <code>pg_miss()</code>, no fill will be in progress and <code>g_pftcb</code> will be NULL.
- In this case, the page fill worker thread will call <code>pg_startfill()</code>.
- That function will perform the following operations:
- <ul>
- <li>
- Call the architecture-specific function <code>up_checkmapping()</code> to see if the page fill
- still needs to be performed.
- In certain conditions, the page fault may occur on several threads and be queued multiple times.
- In this corner case, the blocked task will simply be restarted (see the logic below for the
- case of normal completion of the fill operation).
- </li>
- <li>
- Call <code>up_allocpage(tcb, &vpage)</code>.
- This architecture-specific function will set aside page in memory and map to virtual address (vpage).
- If all available pages are in-use (the typical case),
- this function will select a page in-use, un-map it, and make it available.
- </li>
- <li>
- Call the architecture-specific function <code>up_fillpage()</code>.
- Two versions of the up_fillpage function are supported -- a blocking and a non-blocking version based upon the configuratin setting <code>CONFIG_PAGING_BLOCKINGFILL</code>.
- <ul>
- <li>
- If <code>CONFIG_PAGING_BLOCKINGFILL</code> is defined, then up_fillpage is blocking call.
- In this case, <code>up_fillpage()</code> will accept only (1) a reference to the TCB that requires the fill.
- Architecture-specific context information within the TCB will be sufficient to perform the fill.
- And (2) the (virtual) address of the allocated page to be filled.
- The resulting status of the fill will be provided by return value from <code>up_fillpage()</code>.
- </li>
- <li>
- If <code>CONFIG_PAGING_BLOCKINGFILL</code> is defined, then up_fillpage is non-blocking call.
- In this case <code>up_fillpage()</code> will accept an additional argument:
- The page fill worker thread will provide a callback function, <code>pg_callback</code>.
- This function is non-blocking, it will start an asynchronous page fill.
- After calling the non-blocking <code>up_fillpage()</code>, the page fill worker thread will wait to be signaled for the next event -- the fill completion event.
- The callback function will be called when the page fill is finished (or an error occurs).
- The resulting status of the fill will be providing as an argument to the callback functions.
- This callback will probably occur from interrupt level.
- </ul>
- </li>
- </ul>
-</p>
-<p>
- In any case, while the fill is in progress, other tasks may execute.
- If another page fault occurs during this time, the faulting task will be blocked, its TCB will be added (in priority order) to <code>g_waitingforfill</code>, and the priority of the page worker task may be boosted.
- But no action will be taken until the current page fill completes.
- NOTE: The IDLE task must also be fully <a href="#MemoryOrg">locked</a> in memory.
- The IDLE task cannot be blocked.
- It the case where all tasks are blocked waiting for a page fill, the IDLE task must still be available to run.
-<p>
- The architecture-specific functions, <code>up_checkmapping()</code>, <code>up_allocpage(tcb, &vpage)</code> and <code>up_fillpage(page, pg_callback)</code>
- will be prototyped in <code>include/nuttx/arch.h</code>
-</p>
-
-<a name="FillComplete"><h2>Fill Complete</h2></a>
-
-<p>
- For the blocking <code>up_fillpage()</code>, the result of the fill will be returned directly from the call to <code>up_fillpage</code>.
-</p>
-<p>
- For the non-blocking <code>up_fillpage()</code>, the architecture-specific driver call the <code>pg_callback()</code> that was provided to <code>up_fillpage()</code> when the fill completes.
- In this case, the <code>pg_callback()</code> will probably be called from driver interrupt-level logic.
- The driver will provide the result of the fill as an argument to the callback function.
- NOTE: <code>pg_callback()</code> must also be <a href="#MemoryOrg">locked</a> in memory.
-</p>
-<p>
- In this non-blocking case, the callback <code>pg_callback()</code> will perform the following operations when it is notified that the fill has completed:
- <ul>
- <li>
- Verify that <code>g_pftcb</code> is non-NULL.
- </li>
- <li>
- Find the higher priority between the task waiting for the fill to complete in <code>g_pftcb</code> and the task waiting at the head of the <code>g_waitingforfill</code> list.
- That will be the priority of he highest priority task waiting for a fill.
- </li>
- <li>
- If this higher priority is higher than current page fill worker thread, then boost worker thread's priority to that level.
- Thus, the page fill worker thread will always run at the priority of the highest priority task that is waiting for a fill.
- </li>
- <li>
- Save the result of the fill operation.
- </li>
- <li>
- Signal the page fill worker thread.
- </li>
- </ul>
-</p>
-
-<a name="TaskResumption"><h2>Task Resumption</h2></a>
-
-<p>
- For the non-blocking <code>up_fillpage()</code>, the page fill worker thread will detect that the page fill is complete when it is awakened with <code>g_pftcb</code> non-NULL and fill completion status from <code>pg_callback</code>.
- In the non-blocking case, the page fill worker thread will know that the page fill is complete when <code>up_fillpage()</code> returns.
-</p>
-<p>
- In this either, the page fill worker thread will:
- <ul>
- <li>
- Verify consistency of state information and <code>g_pftcb</code>.
- </li>
- <li>
- Verify that the page fill completed successfully, and if so,
- </li>
- <li>
- Call <code>up_unblocktask(g_pftcb)</code> to make the task that just received the fill ready-to-run.
- </li>
- <li>
- Check if the <code>g_waitingforfill</code> list is empty.
- If not:
- <ul>
- <li>
- Remove the highest priority task waiting for a page fill from <code>g_waitingforfill</code>,
- </li>
- <li>
- Save the task's TCB in <code>g_pftcb</code>,
- </li>
- <li>
- If the priority of the thread in <code>g_pftcb</code>, is higher in priority than the default priority of the page fill worker thread, then set the priority of the page fill worker thread to that priority.
- </li>
- <li>
- Call <code>pg_startfill()</code> which will start the next fill (as described above).
- </li>
- </ul>
- </li>
- <li>
- Otherwise,
- <ul>
- <li>
- Set <code>g_pftcb</code> to NULL.
- </li>
- <li>
- Restore the default priority of the page fill worker thread.
- </li>
- <li>
- Wait for the next fill related event (a new page fault).
- </li>
- </ul>
- </li>
- </ul>
-</p>
-
-<table width ="100%">
- <tr bgcolor="#e4e4e4">
- <td>
- <a name="ArchSupport"><h1>Architecture-Specific Support Requirements</h1></a>
- </td>
- </tr>
-</table>
-
-<a name="MemoryOrg"><h2>Memory Organization</h2></a>
-
-<p>
- <b>Memory Regions</b>.
- Chip specific logic will map the virtual and physical address spaces into three general regions:
- <ol>
- <li>
- A .text region containing "<a href="#MemoryOrg">locked-in-memory</a>" code that is always avaialable and will never cause a page fault.
- This locked memory is loaded at boot time and remains resident for all time.
- This memory regions must include:
- <ul>
- <li>
- All logic for all interrupt pathes.
- All interrupt logic must be locked in memory because the design present here will not support page faults from interrupt handlers.
- This includes the page fault handling logic and <a href="#PageFaults"><code>pg_miss()</code></a> that is called from the page fault handler.
- It also includes the <a href="#FillComplete"><code>pg_callback()</code></a> function that wakes up the page fill worker thread
- and whatever architecture-specific logic that calls <code>pg_callback()</code>.
- </li>
- <li>
- All logic for the IDLE thread.
- The IDLE thread must always be ready to run and cannot be blocked for any reason.
- </li>
- <li>
- All of the page fill worker thread must be locked in memory.
- This thread must execute in order to unblock any thread waiting for a fill.
- It this thread were to block, there would be no way to complete the fills!
- </ul>
- </li>
- <li>
- A .text region containing pages that can be assigned allocated, mapped to various virtual addresses, and filled from some mass storage medium.
- </li>
- <li>
- And a fixed RAM space for .bss, .text, and .heap.
- </li>
- </ol>
-</p>
-<p>
- This memory organization is illustrated in the following table.
- Notice that:
- <ul>
- <li>
- There is a one-to-one relationship between pages in the virtual address space and between pages of .text in the non-volatile mass storage device.
- </li>
- <li>
- There are, however, far fewer physical pages available than virtual pages.
- Only a subset of physical pages will be mapped to virtual pages at any given time.
- This mapping will be performed on-demand as needed for program execution.
- </ul>
-</p>
-
-<center><table width="80%">
-<tr>
- <th width="33%">SRAM</th>
- <th width="33%">Virtual Address Space</th>
- <th width="34%">Non-Volatile Storage</th>
-</tr>
-<tr>
- <td> </td>
- <td bgcolor="lightslategray">DATA</td>
- <td> </td>
-</tr>
-<tr>
- <td> </td>
- <td bgcolor="lightskyblue">Virtual Page <i>n</i> (<i>n</i> > <i>m</i>)</td>
- <td bgcolor="lightskyblue">Stored Page <i>n</i></td>
-</tr>
-<tr>
- <td> </td>
- <td bgcolor="lightskyblue">Virtual Page <i>n-1</i></td>
- <td bgcolor="lightskyblue">Stored Page <i>n-1</i></td>
-</tr>
-<tr>
- <td bgcolor="lightslategray">DATA</td>
- <td bgcolor="lightskyblue">...</td>
- <td bgcolor="lightskyblue">...</td>
-</tr>
-<tr>
- <td bgcolor="lightskyblue">Physical Page <i>m</i> (<i>m</i> < <i>n</i>)</td>
- <td bgcolor="lightskyblue">...</td>
- <td bgcolor="lightskyblue">...</td>
-</tr>
-<tr>
- <td bgcolor="lightskyblue">Physical Page <i>m-1</i></td>
- <td bgcolor="lightskyblue">...</td>
- <td bgcolor="lightskyblue">...</td>
-</tr>
-<tr>
- <td bgcolor="lightskyblue">...</td>
- <td bgcolor="lightskyblue">...</td>
- <td bgcolor="lightskyblue">...</td>
-</tr>
-<tr>
- <td bgcolor="lightskyblue">Physical Page <i>1</i></td>
- <td bgcolor="lightskyblue">Virtual Page <i>1</i></td>
- <td bgcolor="lightskyblue">Stored Page <i>1</i></td>
-</tr>
-<tr>
- <td bgcolor="slategray">Locked Memory</td>
- <td bgcolor="slategray">Locked Memory</td>
- <td bgcolor="slategray">Memory Resident</td>
-</tr>
-</table></center>
-
-<p>
- <b>Example</b>.
- As an example, suppose that the size of the SRAM is 192Kb (as in the NXP LPC3131). And suppose further that:
- <ul>
- <li>
- The size of the locked, memory resident .text area is 32Kb, and
- </li>
- <li>
- The size of the DATA area is 64Kb.
- </li>
- <li>
- The size of one, managed page is 1Kb.
- </li>
- <li>
- The size of the whole .text image on the non-volatile, mass storage device is 1024Kb.
- </li>
- </ul>
-<p>
- Then, the size of the locked, memory resident code is 32Kb (<i>m</i>=32 pages).
- The size of the physical page region is 96Kb (96 pages), and the
- size of the data region is 64 pages.
- And the size of the virtual paged region must then be greater than or equal to (1024-32) or 992 pages (<i>n</i>).
-</p>
-
-<p>
- <b>Building the Locked, In-Memory Image</b>.
- One way to accomplish this would be a two phase link:
- <ul>
- <li>
- In the first phase, create a partially linked objected containing all interrupt/exception handling logic, the page fill worker thread plus all parts of the IDLE thread (which must always be available for execution).
- </li>
- <li>
- All of the <code>.text</code> and <code>.rodata</code> sections of this partial link should be collected into a single section.
- </li>
- <li>
- The second link would link the partially linked object along with the remaining object to produce the final binary.
- The linker script should position the "special" section so that it lies in a reserved, "non-swappable" region.
- </ul>
-</p>
-
-<a name="ArchFuncs"><h2>Architecture-Specific Functions</h2></a>
-
-<p>
- Most standard, architecture-specific functions are declared in <code>include/nuttx/arch.h</code>.
- However, for the case of this paging logic, the architecture specific functions are declared in <code>include/nuttx/page.h</code>.
- Standard, architecture-specific functions that should already be provided in the architecture port.
- The following are used by the common paging logic:
-</p>
-<ul><dl>
- <dt>
- <code>void up_block_task(FAR _TCB *tcb, tstate_t task_state);</code>
- </dt>
- <dd>
- 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 by the on-demand paging logic in order to block the task that requires the
- page fill, and to
- </dd>
- <dt>
- <code>void up_unblock_task(FAR _TCB *tcb);</code>
- </dt>
- <dd>
- 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.
- This function will be called
- </dd>
-</dl></ul>
-
-<p>
- New, additional functions that must be implemented just for on-demand paging support:
-</p>
-
-<ul><dl>
- <dt>
- <code>int up_checkmapping(FAR _TCB *tcb);</code>
- </dt>
- <dd>
- The function <code>up_checkmapping()</code> returns an indication if the page fill still needs to performed or not.
- In certain conditions, the page fault may occur on several threads and be queued multiple times.
- This function will prevent the same page from be filled multiple times.
- </dd>
- <dt>
- <code>int up_allocpage(FAR _TCB *tcb, FAR void *vpage);</code>
- </dt>
- <dd>
- This architecture-specific function will set aside page in memory and map to its correct virtual address.
- Architecture-specific context information saved within the TCB will provide the function with the information needed to identify the virtual miss address.
- This function will return the allocated physical page address in <code>vpage</code>.
- The size of the underlying physical page is determined by the configuration setting <code>CONFIG_PAGING_PAGESIZE</code>.
- NOTE: This function must <i>always</i> return a page allocation.
- If all available pages are in-use (the typical case), then this function will select a page in-use, un-map it, and make it available.
- </dd>
- <dt><code>int up_fillpage(FAR _TCB *tcb, FAR const void *vpage, void (*pg_callback)(FAR _TCB *tcb, int result));</code>
- </dt>
- The actual filling of the page with data from the non-volatile, must be performed by a separate call to the architecture-specific function, <code>up_fillpage()</code>.
- This will start asynchronous page fill.
- The common paging logic will provide a callback function, <code>pg_callback</code>, that will be called when the page fill is finished (or an error occurs).
- This callback is assumed to occur from an interrupt level when the device driver completes the fill operation.
- </dt>
-</dl></ul>
-</body>
-</html>
-
+<html>
+<head>
+<title>On-Demand Paging</title>
+</head>
+<body background="backgd.gif">
+<hr><hr>
+<table width ="100%">
+ <tr align="center" bgcolor="#e4e4e4">
+ <td>
+ <h1><big><font color="#3c34ec"><i>On-Demand Paging</i></font></big></h1>
+ <h2><font color="#dc143c">>>> Under Construction <<<</font></h2>
+ <p>Last Updated: August 12, 2010</p>
+ </td>
+ </tr>
+</table>
+<hr><hr>
+
+<table width ="100%">
+ <tr bgcolor="#e4e4e4">
+ <td>
+ <h1>Table of Contents</h1>
+ </td>
+ </tr>
+</table>
+
+<center><table width ="80%">
+<tr>
+ <td>
+ <table>
+ <tr>
+ <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
+ <td>
+ <a href="#Introduction">Introduction</a>
+ </td>
+ </tr>
+ <tr>
+ <td> </td>
+ <td>
+ <a href="#Overview">Overview</a>
+ </td>
+ </tr>
+ <tr>
+ <td> </td>
+ <td>
+ <a href="#Terminology">Terminology</a>
+ </td>
+ </tr>
+ </table>
+ </td>
+</tr>
+<tr>
+ <td>
+ <table>
+ <tr>
+ <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
+ <td>
+ <a href="#NuttXDesign">NuttX Common Logic Design Description</a>
+ </td>
+ </tr>
+ <tr>
+ <td> </td>
+ <td>
+ <a href="#Initialization">Initialization</a>
+ </td>
+ </tr>
+ <tr>
+ <td> </td>
+ <td>
+ <a href="#PageFaults">Page Faults</a>
+ </td>
+ </tr>
+ <tr>
+ <td> </td>
+ <td>
+ <a href="#FillInitiation">Fill Initiation</a>
+ </td>
+ </tr>
+ <tr>
+ <td> </td>
+ <td>
+ <a href="#FillComplete">Fill Complete</a>
+ </td>
+ </tr>
+ <tr>
+ <td> </td>
+ <td>
+ <a href="#TaskResumption">Task Resumption</a>
+ </td>
+ </tr>
+ </table>
+ </td>
+</tr>
+<tr>
+ <td>
+ <table>
+ <tr>
+ <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
+ <td>
+ <a href="#ArchSupport">Architecture-Specific Support Requirements</a>
+ </td>
+ </tr>
+ <tr>
+ <td> </td>
+ <td>
+ <a href="#MemoryOrg">Memory Organization</a>
+ </td>
+ </tr>
+ <tr>
+ <td> </td>
+ <td>
+ <a href="#ArchFuncs">Architecture-Specific Functions</a>
+ </td>
+ </tr>
+ </table>
+ </td>
+</tr>
+
+</table></center>
+
+<table width ="100%">
+ <tr bgcolor="#e4e4e4">
+ <td>
+ <a name="Introduction"><h1>Introduction</h1></a>
+ </td>
+ </tr>
+</table>
+<a name="Overview"><h2>Overview</h2></a>
+
+<p>
+ This document summarizes the design of NuttX on-demand paging.
+ This feature permits embedded MCUs with some limited RAM space to execute large programs from some non-random access media.
+ This feature was first discussed in this email thread:
+ <a href="http://tech.groups.yahoo.com/group/nuttx/message/213">http://tech.groups.yahoo.com/group/nuttx/message/213</a>.
+</p>
+<p>
+ What kind of platforms can support NuttX on-demang paging?
+ <ol>
+ <li>
+ The MCU should have some large, probably low-cost non-volatile storage such as serial FLASH or an SD card.
+ This storage probably does not support non-random access (otherwise, why not just execute the program directly on the storage media).
+ SD and serial FLASH are inexpensive and do not require very many pins and SPI support is prevalent in just about all MCUs.
+ This large serial FLASH would contain a big program. Perhaps a program of several megabytes in size.
+ </li>
+ <li>
+ The MCU must have a (relatively) small block of fast SRAM from which it can execute code.
+ A size of, say 256K (or 192K as in the NXP LPC3131) would be sufficient for many applications.
+ </li>
+ <li>
+ The MCU has an MMU (again like the NXP LPC3131).
+ </li>
+ </ol>
+</p>
+<p>
+ If the platform meets these requirement, then NuttX can provide on-demand paging:
+ It can copy .text from the large program in non-volatile media into RAM as needed to execute a huge program from the small RAM.
+</p>
+
+<a name="Terminology"><h2>Terminology</h2></a>
+
+<dl>
+ <dt><code>g_waitingforfill</code></dt>
+ <dd>An OS list that is used to hold the TCBs of tasks that are waiting for a page fill.</dd>
+ <dt><code>g_pftcb</code></dt>
+ <dd>A variable that holds a reference to the TCB of the thread that is currently be re-filled.</dd>
+ <dt><code>g_pgworker</code></dt>
+ <dd>The <i>process</i> ID of of the thread that will perform the page fills.</dd>
+ <dt><code>pg_callback()</code></dt>
+ <dd>The callback function that is invoked from a driver when the fill is complete.</dd>
+ <dt><code>pg_miss()</code></dt>
+ <dd>The function that is called from architecture-specific code to handle a page fault.</dd>
+ <dt><code>TCB</code></dt>
+ <dd>Task Control Block</dd>
+</dl>
+
+<table width ="100%">
+ <tr bgcolor="#e4e4e4">
+ <td>
+ <a name="NuttXDesign"><h1>NuttX Common Logic Design Description</h1></a>
+ </td>
+ </tr>
+</table>
+
+
+<a name="Initialization"><h2>Initialization</h2></a>
+
+<p>
+ The following declarations will be added.
+ <ul>
+ <li>
+ <b><code>g_waitingforfill</code></b>.
+ A doubly linked list that will be used to implement a prioritized list of the TCBs of tasks that are waiting for a page fill.
+ </li>
+ <li>
+ <b><code>g_pgworker</code></b>.
+ The <i>process</i> ID of of the thread that will perform the page fills
+ </li>
+ </ul>
+</p>
+<p>
+ During OS initialization in <code>sched/os_start.c</code>, the following steps
+ will be performed:
+ <ul>
+ <li>
+ The <code>g_waitingforfill</code> queue will be initialized.
+ </li>
+ <li>
+ The special, page fill worker thread, will be started.
+ The <code>pid</code> of the page will worker thread will be saved in <code>g_pgworker</code>.
+ Note that we need a special worker thread to perform fills;
+ we cannot use the "generic" worker thread facility because we cannot be
+ assured that all actions called by that worker thread will always be resident in memory.
+ </li>
+ </ul>
+ </p>
+ <p>
+ Declarations for <code>g_waitingforfill</code>, <code>g_pgworker</code>, and other
+ internal, private definitions will be provided in <code>sched/pg_internal.h</code>.
+ All public definitions that should be used by the architecture-specific code will be available
+ in <code>include/nuttx/page.h</code>.
+ Most architecture-specific functions are declared in <code>include/nuttx/arch.h</code>,
+ but for the case of this paging logic, those architecture specific functions are instead declared in <code>include/nuttx/page.h</code>.
+ </p>
+
+<a name="PageFaults"><h2>Page Faults</h2></a>
+
+<p>
+ <b>Page fault exception handling</b>.
+ Page fault handling is performed by the function <code>pg_miss()</code>.
+ This function is called from architecture-specific memory segmentation
+ fault handling logic. This function will perform the following
+ operations:
+ <ol>
+ <li>
+ <b>Sanity checking</b>.
+ This function will ASSERT if the currently executing task is the page fill worker thread.
+ The page fill worker thread is how the the page fault is resolved and all logic associated with the page fill worker
+ must be "<a href="#MemoryOrg">locked</a>" and always present in memory.
+ </li>
+ <li>
+ <b>Block the currently executing task</b>.
+ This function will call <code>up_block_task()</code> to block the task at the head of the ready-to-run list.
+ This should cause an interrupt level context switch to the next highest priority task.
+ The blocked task will be marked with state <code>TSTATE_WAIT_PAGEFILL</code> and will be retained in the <code>g_waitingforfill</code> prioritized task list.
+ </li>
+ <li>
+ <b>Boost the page fill worker thread priority</b>.
+ Check the priority of the task at the head of the <code>g_waitingforfill</code> list.
+ If the priority of that task is higher than the current priority of the page fill worker thread, then boost the priority of the page fill worker thread to that priority.
+ Thus, the page fill worker thread will always run at the priority of the highest priority task that is waiting for a fill.
+ </li>
+ <li>
+ <b>Signal the page fill worker thread</b>.
+ Is there a page already being filled?
+ If not then signal the page fill worker thread to start working on the queued page fill requests.
+ </li>
+ </ol>
+</p>
+<p>
+ When signaled from <code>pg_miss()</code>, the page fill worker thread will be awakenend and will initiate the fill operation.
+</p>
+<p>
+ <b>Input Parameters.</b>
+ None -- The head of the ready-to-run list is assumed to be that task that caused the exception.
+ The current task context should already be saved in the TCB of that task.
+ No additional inputs are required.
+</p>
+<p>
+ <b>Assumptions</b>.
+ <ul>
+ <li>
+ It is assumed that this function is called from the level of an exception handler and that all interrupts are disabled.
+ </li>
+ <li>
+ The <code>pg_miss()</code> must be "<a href="#MemoryOrg">locked</a>" in memory.
+ Calling <code>pg_miss()</code> cannot cause a nested page fault.
+ </li>
+ <li>
+ It is assumed that currently executing task (the one at the head of the ready-to-run list) is the one that cause the fault.
+ This will always be true unless the page fault occurred in an interrupt handler.
+ Interrupt handling logic must always be available and "<a href="#MemoryOrg">locked</a>" into memory so that page faults never come from interrupt handling.
+ </li>
+ <li>
+ The architecture-specific page fault exception handling has already verified that the exception did not occur from interrupt/exception handling logic.
+ </li>
+ <li>
+ As mentioned above, the task causing the page fault must not be the page fill worker thread because that is the only way to complete the page fill.
+ </li>
+ </ul>
+</p>
+
+<a name="FillInitiation"><h2>Fill Initiation</h2></a>
+
+<p>
+ The page fill worker thread will be awakened on one of three conditions:
+ <ul>
+ <li>
+ When signaled by <code>pg_miss()</code>, the page fill worker thread will be awakenend (see above),
+ </li>
+ <li>
+ From <code>pg_callback()</code> after completing last fill (when <code>CONFIG_PAGING_BLOCKINGFILL</code> is defined... see below), or
+ </li>
+ <li>
+ A configurable timeout expires with no activity.
+ This timeout can be used to detect failure conditions such things as fills that never complete.
+ </li>
+ </ul>
+</p>
+
+<p>
+ The page fill worker thread will maintain a static variable called <code>_TCB *g_pftcb</code>.
+ If no fill is in progress, <code>g_pftcb</code> will be NULL.
+ Otherwise, it will point to the TCB of the task which is receiving the fill that is in progess.
+</p>
+<ul><small>
+ <b>NOTE</b>:
+ I think that this is the only state in which a TCB does not reside in some list.
+ Here is it in limbo, outside of the normally queuing while the page file is in progress.
+ While here, it will be marked with TSTATE_TASK_INVALID.
+</small></ul>
+
+<p>
+ When awakened from <code>pg_miss()</code>, no fill will be in progress and <code>g_pftcb</code> will be NULL.
+ In this case, the page fill worker thread will call <code>pg_startfill()</code>.
+ That function will perform the following operations:
+ <ul>
+ <li>
+ Call the architecture-specific function <code>up_checkmapping()</code> to see if the page fill
+ still needs to be performed.
+ In certain conditions, the page fault may occur on several threads and be queued multiple times.
+ In this corner case, the blocked task will simply be restarted (see the logic below for the
+ case of normal completion of the fill operation).
+ </li>
+ <li>
+ Call <code>up_allocpage(tcb, &vpage)</code>.
+ This architecture-specific function will set aside page in memory and map to virtual address (vpage).
+ If all available pages are in-use (the typical case),
+ this function will select a page in-use, un-map it, and make it available.
+ </li>
+ <li>
+ Call the architecture-specific function <code>up_fillpage()</code>.
+ Two versions of the up_fillpage function are supported -- a blocking and a non-blocking version based upon the configuratin setting <code>CONFIG_PAGING_BLOCKINGFILL</code>.
+ <ul>
+ <li>
+ If <code>CONFIG_PAGING_BLOCKINGFILL</code> is defined, then up_fillpage is blocking call.
+ In this case, <code>up_fillpage()</code> will accept only (1) a reference to the TCB that requires the fill.
+ Architecture-specific context information within the TCB will be sufficient to perform the fill.
+ And (2) the (virtual) address of the allocated page to be filled.
+ The resulting status of the fill will be provided by return value from <code>up_fillpage()</code>.
+ </li>
+ <li>
+ If <code>CONFIG_PAGING_BLOCKINGFILL</code> is defined, then up_fillpage is non-blocking call.
+ In this case <code>up_fillpage()</code> will accept an additional argument:
+ The page fill worker thread will provide a callback function, <code>pg_callback</code>.
+ This function is non-blocking, it will start an asynchronous page fill.
+ After calling the non-blocking <code>up_fillpage()</code>, the page fill worker thread will wait to be signaled for the next event -- the fill completion event.
+ The callback function will be called when the page fill is finished (or an error occurs).
+ The resulting status of the fill will be providing as an argument to the callback functions.
+ This callback will probably occur from interrupt level.
+ </ul>
+ </li>
+ </ul>
+</p>
+<p>
+ In any case, while the fill is in progress, other tasks may execute.
+ If another page fault occurs during this time, the faulting task will be blocked, its TCB will be added (in priority order) to <code>g_waitingforfill</code>, and the priority of the page worker task may be boosted.
+ But no action will be taken until the current page fill completes.
+ NOTE: The IDLE task must also be fully <a href="#MemoryOrg">locked</a> in memory.
+ The IDLE task cannot be blocked.
+ It the case where all tasks are blocked waiting for a page fill, the IDLE task must still be available to run.
+<p>
+ The architecture-specific functions, <code>up_checkmapping()</code>, <code>up_allocpage(tcb, &vpage)</code> and <code>up_fillpage(page, pg_callback)</code>
+ will be prototyped in <code>include/nuttx/arch.h</code>
+</p>
+
+<a name="FillComplete"><h2>Fill Complete</h2></a>
+
+<p>
+ For the blocking <code>up_fillpage()</code>, the result of the fill will be returned directly from the call to <code>up_fillpage</code>.
+</p>
+<p>
+ For the non-blocking <code>up_fillpage()</code>, the architecture-specific driver call the <code>pg_callback()</code> that was provided to <code>up_fillpage()</code> when the fill completes.
+ In this case, the <code>pg_callback()</code> will probably be called from driver interrupt-level logic.
+ The driver will provide the result of the fill as an argument to the callback function.
+ NOTE: <code>pg_callback()</code> must also be <a href="#MemoryOrg">locked</a> in memory.
+</p>
+<p>
+ In this non-blocking case, the callback <code>pg_callback()</code> will perform the following operations when it is notified that the fill has completed:
+ <ul>
+ <li>
+ Verify that <code>g_pftcb</code> is non-NULL.
+ </li>
+ <li>
+ Find the higher priority between the task waiting for the fill to complete in <code>g_pftcb</code> and the task waiting at the head of the <code>g_waitingforfill</code> list.
+ That will be the priority of he highest priority task waiting for a fill.
+ </li>
+ <li>
+ If this higher priority is higher than current page fill worker thread, then boost worker thread's priority to that level.
+ Thus, the page fill worker thread will always run at the priority of the highest priority task that is waiting for a fill.
+ </li>
+ <li>
+ Save the result of the fill operation.
+ </li>
+ <li>
+ Signal the page fill worker thread.
+ </li>
+ </ul>
+</p>
+
+<a name="TaskResumption"><h2>Task Resumption</h2></a>
+
+<p>
+ For the non-blocking <code>up_fillpage()</code>, the page fill worker thread will detect that the page fill is complete when it is awakened with <code>g_pftcb</code> non-NULL and fill completion status from <code>pg_callback</code>.
+ In the non-blocking case, the page fill worker thread will know that the page fill is complete when <code>up_fillpage()</code> returns.
+</p>
+<p>
+ In this either, the page fill worker thread will:
+ <ul>
+ <li>
+ Verify consistency of state information and <code>g_pftcb</code>.
+ </li>
+ <li>
+ Verify that the page fill completed successfully, and if so,
+ </li>
+ <li>
+ Call <code>up_unblocktask(g_pftcb)</code> to make the task that just received the fill ready-to-run.
+ </li>
+ <li>
+ Check if the <code>g_waitingforfill</code> list is empty.
+ If not:
+ <ul>
+ <li>
+ Remove the highest priority task waiting for a page fill from <code>g_waitingforfill</code>,
+ </li>
+ <li>
+ Save the task's TCB in <code>g_pftcb</code>,
+ </li>
+ <li>
+ If the priority of the thread in <code>g_pftcb</code>, is higher in priority than the default priority of the page fill worker thread, then set the priority of the page fill worker thread to that priority.
+ </li>
+ <li>
+ Call <code>pg_startfill()</code> which will start the next fill (as described above).
+ </li>
+ </ul>
+ </li>
+ <li>
+ Otherwise,
+ <ul>
+ <li>
+ Set <code>g_pftcb</code> to NULL.
+ </li>
+ <li>
+ Restore the default priority of the page fill worker thread.
+ </li>
+ <li>
+ Wait for the next fill related event (a new page fault).
+ </li>
+ </ul>
+ </li>
+ </ul>
+</p>
+
+<table width ="100%">
+ <tr bgcolor="#e4e4e4">
+ <td>
+ <a name="ArchSupport"><h1>Architecture-Specific Support Requirements</h1></a>
+ </td>
+ </tr>
+</table>
+
+<a name="MemoryOrg"><h2>Memory Organization</h2></a>
+
+<p>
+ <b>Memory Regions</b>.
+ Chip specific logic will map the virtual and physical address spaces into three general regions:
+ <ol>
+ <li>
+ A .text region containing "<a href="#MemoryOrg">locked-in-memory</a>" code that is always avaialable and will never cause a page fault.
+ This locked memory is loaded at boot time and remains resident for all time.
+ This memory regions must include:
+ <ul>
+ <li>
+ All logic for all interrupt paths.
+ All interrupt logic must be locked in memory because the design present here will not support page faults from interrupt handlers.
+ This includes the page fault handling logic and <a href="#PageFaults"><code>pg_miss()</code></a> that is called from the page fault handler.
+ It also includes the <a href="#FillComplete"><code>pg_callback()</code></a> function that wakes up the page fill worker thread
+ and whatever architecture-specific logic that calls <code>pg_callback()</code>.
+ </li>
+ <li>
+ All logic for the IDLE thread.
+ The IDLE thread must always be ready to run and cannot be blocked for any reason.
+ </li>
+ <li>
+ All of the page fill worker thread must be locked in memory.
+ This thread must execute in order to unblock any thread waiting for a fill.
+ It this thread were to block, there would be no way to complete the fills!
+ </ul>
+ </li>
+ <li>
+ A .text region containing pages that can be assigned allocated, mapped to various virtual addresses, and filled from some mass storage medium.
+ </li>
+ <li>
+ And a fixed RAM space for .bss, .text, and .heap.
+ </li>
+ </ol>
+</p>
+<p>
+ This memory organization is illustrated in the following table.
+ Notice that:
+ <ul>
+ <li>
+ There is a one-to-one relationship between pages in the virtual address space and between pages of .text in the non-volatile mass storage device.
+ </li>
+ <li>
+ There are, however, far fewer physical pages available than virtual pages.
+ Only a subset of physical pages will be mapped to virtual pages at any given time.
+ This mapping will be performed on-demand as needed for program execution.
+ </ul>
+</p>
+
+<center><table width="80%">
+<tr>
+ <th width="33%">SRAM</th>
+ <th width="33%">Virtual Address Space</th>
+ <th width="34%">Non-Volatile Storage</th>
+</tr>
+<tr>
+ <td> </td>
+ <td bgcolor="lightslategray">DATA</td>
+ <td> </td>
+</tr>
+<tr>
+ <td> </td>
+ <td bgcolor="lightskyblue">Virtual Page <i>n</i> (<i>n</i> > <i>m</i>)</td>
+ <td bgcolor="lightskyblue">Stored Page <i>n</i></td>
+</tr>
+<tr>
+ <td> </td>
+ <td bgcolor="lightskyblue">Virtual Page <i>n-1</i></td>
+ <td bgcolor="lightskyblue">Stored Page <i>n-1</i></td>
+</tr>
+<tr>
+ <td bgcolor="lightslategray">DATA</td>
+ <td bgcolor="lightskyblue">...</td>
+ <td bgcolor="lightskyblue">...</td>
+</tr>
+<tr>
+ <td bgcolor="lightskyblue">Physical Page <i>m</i> (<i>m</i> < <i>n</i>)</td>
+ <td bgcolor="lightskyblue">...</td>
+ <td bgcolor="lightskyblue">...</td>
+</tr>
+<tr>
+ <td bgcolor="lightskyblue">Physical Page <i>m-1</i></td>
+ <td bgcolor="lightskyblue">...</td>
+ <td bgcolor="lightskyblue">...</td>
+</tr>
+<tr>
+ <td bgcolor="lightskyblue">...</td>
+ <td bgcolor="lightskyblue">...</td>
+ <td bgcolor="lightskyblue">...</td>
+</tr>
+<tr>
+ <td bgcolor="lightskyblue">Physical Page <i>1</i></td>
+ <td bgcolor="lightskyblue">Virtual Page <i>1</i></td>
+ <td bgcolor="lightskyblue">Stored Page <i>1</i></td>
+</tr>
+<tr>
+ <td bgcolor="slategray">Locked Memory</td>
+ <td bgcolor="slategray">Locked Memory</td>
+ <td bgcolor="slategray">Memory Resident</td>
+</tr>
+</table></center>
+
+<p>
+ <b>Example</b>.
+ As an example, suppose that the size of the SRAM is 192K (as in the NXP LPC3131). And suppose further that:
+ <ul>
+ <li>
+ The size of the locked, memory resident .text area is 32K, and
+ </li>
+ <li>
+ The size of the DATA area is 64K.
+ </li>
+ <li>
+ The size of one, managed page is 1K.
+ </li>
+ <li>
+ The size of the whole .text image on the non-volatile, mass storage device is 1024K.
+ </li>
+ </ul>
+<p>
+ Then, the size of the locked, memory resident code is 32K (<i>m</i>=32 pages).
+ The size of the physical page region is 96K (96 pages), and the
+ size of the data region is 64 pages.
+ And the size of the virtual paged region must then be greater than or equal to (1024-32) or 992 pages (<i>n</i>).
+</p>
+
+<p>
+ <b>Building the Locked, In-Memory Image</b>.
+ One way to accomplish this would be a two phase link:
+ <ul>
+ <li>
+ In the first phase, create a partially linked objected containing all interrupt/exception handling logic, the page fill worker thread plus all parts of the IDLE thread (which must always be available for execution).
+ </li>
+ <li>
+ All of the <code>.text</code> and <code>.rodata</code> sections of this partial link should be collected into a single section.
+ </li>
+ <li>
+ The second link would link the partially linked object along with the remaining object to produce the final binary.
+ The linker script should position the "special" section so that it lies in a reserved, "non-swappable" region.
+ </ul>
+</p>
+
+<a name="ArchFuncs"><h2>Architecture-Specific Functions</h2></a>
+
+<p>
+ Most standard, architecture-specific functions are declared in <code>include/nuttx/arch.h</code>.
+ However, for the case of this paging logic, the architecture specific functions are declared in <code>include/nuttx/page.h</code>.
+ Standard, architecture-specific functions that should already be provided in the architecture port.
+ The following are used by the common paging logic:
+</p>
+<ul><dl>
+ <dt>
+ <code>void up_block_task(FAR _TCB *tcb, tstate_t task_state);</code>
+ </dt>
+ <dd>
+ 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 by the on-demand paging logic in order to block the task that requires the
+ page fill, and to
+ </dd>
+ <dt>
+ <code>void up_unblock_task(FAR _TCB *tcb);</code>
+ </dt>
+ <dd>
+ 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.
+ This function will be called
+ </dd>
+</dl></ul>
+
+<p>
+ New, additional functions that must be implemented just for on-demand paging support:
+</p>
+
+<ul><dl>
+ <dt>
+ <code>int up_checkmapping(FAR _TCB *tcb);</code>
+ </dt>
+ <dd>
+ The function <code>up_checkmapping()</code> returns an indication if the page fill still needs to performed or not.
+ In certain conditions, the page fault may occur on several threads and be queued multiple times.
+ This function will prevent the same page from be filled multiple times.
+ </dd>
+ <dt>
+ <code>int up_allocpage(FAR _TCB *tcb, FAR void *vpage);</code>
+ </dt>
+ <dd>
+ This architecture-specific function will set aside page in memory and map to its correct virtual address.
+ Architecture-specific context information saved within the TCB will provide the function with the information needed to identify the virtual miss address.
+ This function will return the allocated physical page address in <code>vpage</code>.
+ The size of the underlying physical page is determined by the configuration setting <code>CONFIG_PAGING_PAGESIZE</code>.
+ NOTE: This function must <i>always</i> return a page allocation.
+ If all available pages are in-use (the typical case), then this function will select a page in-use, un-map it, and make it available.
+ </dd>
+ <dt><code>int up_fillpage(FAR _TCB *tcb, FAR const void *vpage, void (*pg_callback)(FAR _TCB *tcb, int result));</code>
+ </dt>
+ The actual filling of the page with data from the non-volatile, must be performed by a separate call to the architecture-specific function, <code>up_fillpage()</code>.
+ This will start asynchronous page fill.
+ The common paging logic will provide a callback function, <code>pg_callback</code>, that will be called when the page fill is finished (or an error occurs).
+ This callback is assumed to occur from an interrupt level when the device driver completes the fill operation.
+ </dt>
+</dl></ul>
+</body>
+</html>
+
diff --git a/Documentation/NuttxPortingGuide.html b/Documentation/NuttxPortingGuide.html
index e605dd109d5cba8b636654ef37c8b9b38fdbfb25..a339b3a99023e0c3c0589e0203d046140bf10a02 100644
--- a/Documentation/NuttxPortingGuide.html
+++ b/Documentation/NuttxPortingGuide.html
@@ -3935,7 +3935,7 @@ build
16-bit addressability have smaller overhead than devices that
support 32-bit addressability. However, there are many MCUs
that support 32-bit addressability <i>but</i> have internal SRAM
- of size less than or equal to 64Kb. In this case, CONFIG_MM_SMALL
+ of size less than or equal to 64K. In this case, CONFIG_MM_SMALL
can be defined so that those MCUs will also benefit from the
smaller, 16-bit-based allocation overhead.
</li>
@@ -4740,7 +4740,7 @@ build
<li>
<code>CONFIG_P14201_FRAMEBUFFER</code>:
If defined, accesses will be performed using an in-memory copy of the OLEDs GDDRAM.
- This cost of this buffer is 128 * 96 / 2 = 6Kb.
+ This cost of this buffer is 128 * 96 / 2 = 6K.
If this is defined, then the driver will be fully functional.
If not, then it will have the following limitations:
<ul>
diff --git a/Documentation/NxWidgets.html b/Documentation/NxWidgets.html
index cef99d494335baa97d274c1fa24f1addce1f34ed..1678d9ebe7fa2e5cc1eddc3ef5bc058ed0a60a1f 100755
--- a/Documentation/NxWidgets.html
+++ b/Documentation/NxWidgets.html
@@ -33,7 +33,7 @@
<li><b>Small Footprint</b>.
NXWidgets is tailored for use MCUs in embedded applications.
It is ideally suited for mid- and upper-range of most MCU families.
- A complete NXWidgets is possible in as little as 40Kb of FLASH and maybe 4Kb of SRAM.
+ A complete NXWidgets is possible in as little as 40K of FLASH and maybe 4K of SRAM.
</li>
<li><b>Output Devices</b>.
NXWidgets will work on the high-end frame buffer devices as well as on LCDs connected via serial or parallel ports to a small MCU.
diff --git a/ReleaseNotes b/ReleaseNotes
index 8c6ae0ccb87325200300183b5cd306adda4dee82..26af0e38d4c71af8d7be15030756be23719dcf38 100644
--- a/ReleaseNotes
+++ b/ReleaseNotes
@@ -1668,7 +1668,7 @@ Important bugfixes included:
And feature enhancements:
* The LPC176x Ethernet driver was using all of AHB SRAM Bank0 for
- Ethernet packet buffers (16Kb). An option was added to limit
+ Ethernet packet buffers (16K). An option was added to limit
the amount of SRAM used for packet buffering and to re-use any
extra Bank0 memory for heap.
@@ -2022,7 +2022,7 @@ and is available for download from the SourceForge website. The
* A PCI-based E1000 Ethernet driver (contributed by Yu Qiang)
* New C library functions: inet_addr() (contributed by Yu Qiang),
strndup(), asprintf()
- * Reduced memory allocation overhead for MCUs with small heaps (<64Kb).
+ * Reduced memory allocation overhead for MCUs with small heaps (<64K).
* fdopen() now works with socket descriptors allowing standard
buffered C functions to be used for network communications.
* The NSH ifconfig command can now be used to set or change the
@@ -2062,7 +2062,7 @@ they are, ordered from the least to the most complete:
This port of NuttX to the Amber Web Server from SoC Robotics
(http://www.soc-robotics.com/index.htm). Is only partially in
place. The Amber Web Server is based on an Atmel ATMega128
- (128Kb FLASH but only 4Kb of SRAM).
+ (128K FLASH but only 4K of SRAM).
STATUS: Work on this port has stalled due to toolchain issues. It
is complete, but untested.
@@ -2073,7 +2073,7 @@ they are, ordered from the least to the most complete:
Micropendous3 may be populated with an AT90USB646, 647, 1286,
or 1287. See http://code.google.com/p/opendous/. I have only
the AT90USB647 version for testing. This version has very
- limited memory resources: 64Kb of FLASH and 4Kb of SRAM.
+ limited memory resources: 64K of FLASH and 4K of SRAM.
STATUS: The basic port was released in NuttX-6.5. This basic
port consists only of a "Hello, World!!" example that demonstrates
@@ -2085,8 +2085,8 @@ they are, ordered from the least to the most complete:
This is a port of NuttX to the PJRC Teensy++ 2.0 board. This
board was developed by PJRC (http://pjrc.com/teensy/). The
- Teensy++ 2.0 is based on an Atmel AT90USB1286 MCU with 128Kb
- of FLASH and 8Kb of SRAM; a little more room to move than the
+ Teensy++ 2.0 is based on an Atmel AT90USB1286 MCU with 128K
+ of FLASH and 8K of SRAM; a little more room to move than the
AT90USB647.
STATUS: The basic port was released in NuttX-6.5. This basic
@@ -2109,7 +2109,7 @@ integrated into the normal, general purpose OS.
Most NuttX test applications are console-oriented with lots of
strings used for printf and debug output. These strings are all
stored in SRAM now due to these data accessing issues and even the
-smallest console-oriented applications can quickly fill a 4-8Kb
+smallest console-oriented applications can quickly fill a 4-8K
memory. So, in order for the AVR port to be useful, one of two
things would need to be done:
diff --git a/TODO b/TODO
index 7ffcb9ca807f3b570bc3c4911bd1b6e191a58b64..f9fc558eabca20ae5e6e9a15a7be177493aec91b 100644
--- a/TODO
+++ b/TODO
@@ -1819,7 +1819,7 @@ o mc68hc1x (arch/hc)
Description: There is no script for building in banked mode (more correctly, there
is a script, but logic inside the script has not yet been implemented).
It would be necessary to implement banked mode to able to access more
- the 48Kb of FLASH.
+ the 48K of FLASH.
Status: Open.
Priority: Medium/Low
diff --git a/arch/arm/src/lpc43xx/lpc43_usb0dev.c b/arch/arm/src/lpc43xx/lpc43_usb0dev.c
index 40233ec0f69c99e8e650bba3f67ac5037940a39a..2ce19a32504e7ae856e3b68954dd7d6835c05bc6 100644
--- a/arch/arm/src/lpc43xx/lpc43_usb0dev.c
+++ b/arch/arm/src/lpc43xx/lpc43_usb0dev.c
@@ -69,9 +69,7 @@
#include "up_arch.h"
#include "up_internal.h"
-#include "lpc43_usbotg.h"
-#include "lpc43_evntrtr.h"
-#include "lpc43_syscreg.h"
+#include "lpc43_usb0dev.h"
/*******************************************************************************
* Definitions
diff --git a/arch/arm/src/lpc43xx/lpc43_usb0dev.h b/arch/arm/src/lpc43xx/lpc43_usb0dev.h
new file mode 100644
index 0000000000000000000000000000000000000000..97076cd802f51e2988bd91a200adbb205c18a484
--- /dev/null
+++ b/arch/arm/src/lpc43xx/lpc43_usb0dev.h
@@ -0,0 +1,98 @@
+/************************************************************************************
+ * arch/arm/src/lpc43xx/lpc43_usbdev.h
+ *
+ * Copyright (C) 2009, 2011 Gregory Nutt. All rights reserved.
+ * Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ * used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ************************************************************************************/
+
+#ifndef __ARCH_ARM_SRC_LPC43XX_LPC32_USB0DEV_H
+#define __ARCH_ARM_SRC_LPC43XX_LPC32_USB0DEV_H
+
+/************************************************************************************
+ * Included Files
+ ************************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/usb/usbdev.h>
+#include <stdint.h>
+
+#include "chip.h"
+#include "chip/lpc43_usb0.h"
+
+/************************************************************************************
+ * Public Functions
+ ************************************************************************************/
+
+#ifndef __ASSEMBLY__
+
+#undef EXTERN
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C" {
+#else
+#define EXTERN extern
+#endif
+
+/************************************************************************************
+ * Name: lpc43_usbpullup
+ *
+ * Description:
+ * If USB is supported and the board supports a pullup via GPIO (for USB software
+ * connect and disconnect), then the board software must provide lpc43_pullup.
+ * See include/nuttx/usb/usbdev.h for additional description of this method.
+ * Alternatively, if no pull-up GPIO the following EXTERN can be redefined to be
+ * NULL.
+ *
+ ************************************************************************************/
+
+EXTERN int lpc43_usbpullup(FAR struct usbdev_s *dev, bool enable);
+
+/************************************************************************************
+ * Name: lpc43_usbsuspend
+ *
+ * Description:
+ * Board logic must provide the lpc43_usbsuspend logic if the USBDEV driver is
+ * used. This function is called whenever the USB enters or leaves suspend mode.
+ * This is an opportunity for the board logic to shutdown clocks, power, etc.
+ * while the USB is suspended.
+ *
+ ************************************************************************************/
+
+EXTERN void lpc43_usbsuspend(FAR struct usbdev_s *dev, bool resume);
+
+#undef EXTERN
+#if defined(__cplusplus)
+}
+#endif
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ARCH_ARM_SRC_LPC43XX_LPC32_USB0DEV_H */
+