git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@831 35acf78f-673a-0410-8e92-d51de3d6d3f4
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gdisirio
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@ -29,6 +29,7 @@
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* - @subpage article_jitter
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* - @subpage article_timing
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* - @subpage article_portguide
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* - @subpage article_design
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* .
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*/
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/** @} */
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@ -0,0 +1,112 @@
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/*
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ChibiOS/RT - Copyright (C) 2006-2007 Giovanni Di Sirio.
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This file is part of ChibiOS/RT.
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ChibiOS/RT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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ChibiOS/RT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @page article_design Designing an embedded application
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* @{
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* ChibiOS/RT offers a variety of mechanisms and primitives, often it is
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* better to focus on a single approach for the system design and use only
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* part of the available subsystems.<br>
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* When designing your application you may choose among several design
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* alternatives:
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* - @ref nothreads
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* - @ref messpass
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* - @ref thdshared
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* - @ref thdmixed
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* .
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* @section nothreads Single threaded superloop
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* Correct, single thread, it is not mandatory to use the multithreading
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* features of the OS. You may choose to implements everything as a complex
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* state machine handled in the main thread alone. In this scenario the OS
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* still offers a variety of useful mechanisms:
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* - Interrupt handling.
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* - Virtual Timers, very useful in state machines in order to handle time
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* triggered state transitions.
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* - Power management.
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* - Event Flags and/or Semaphores as communication mechanism between
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* interrupt handlers and the main.
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* - I/O queues.
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* - Memory allocation.
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* - System time.
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* .
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* In this configuration the kernel size is really minimal, everything else
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* is disabled and takes no space. You always have the option to use more
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* threads at a later time in order to perform separate tasks.
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*
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* @section messpass Message Passing
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* In this scenario there are multiple threads in the system that never
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* share data, everything is done by exchanging messages. Each thread
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* represents a service, the other threads can request the service by sending
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* a message.<br>
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* In this scenario the following subsystems can be used:
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* - Synchronous Messages.
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* - Mailboxes (asynchronous message queues).
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* .
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* The advantage of this approach is to not have to deal with mutual exclusion,
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* each functionality is encapsulated into a server thread that sequentially
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* serves all the requests. As example, you can have the following scenario:
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* - A buffers allocator server.
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* - A disk driver server.
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* - A file system server.
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* - One or more client threads.
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* .
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* Example:
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* <br><br>
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* @dot
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digraph example {
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rankdir="RL";
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node [shape=rectangle, fontname=Helvetica, fontsize=8, fixedsize="true",
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width="1.2", height="0.75"];
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edge [fontname=Helvetica, fontsize=8];
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disk [label="Server Thread\nDisk Driver"];
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buf [label="Server Thread\nBuffers Allocator"];
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fs [label="Client&Server Thread\nFile System"];
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cl1 [label="Client Thread"];
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cl2 [label="Client Thread"];
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cl3 [label="Client Thread"];
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fs -> disk [label="I/O request", constraint=false];
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disk -> fs [label="status", style="dotted", constraint=false];
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fs -> buf [label="buffer request"];
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buf -> fs [label="buffer", style="dotted"];
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cl1 -> fs [label="FS transaction"];
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fs -> cl1 [label="result", style="dotted"];
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cl2 -> fs [label="FS transaction"];
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fs -> cl2 [label="result", style="dotted"];
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cl3 -> fs [label="FS transaction"];
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fs -> cl3 [label="result", style="dotted"];
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}
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* @enddot
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* <br><br>
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* Note that the threads should not exchange complex messages but just
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* pointers to data structures in order to optimize the performance.
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* Also note that a thread can be both client and server at the same
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* time, the FS service in the previous scenario as example.
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*
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* @section thdshared Threads sharing data
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* This is the most common scenario, several threads have access to both their
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* private data and shared data. Synchronization happens with one of the
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* mechanisms described in the @ref article_mutual_exclusion article.<br>
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*
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* @section thdmixed Mixed
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* All the above approaches can be freely mixed in a single application but
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* usually I prefer to choose a way and consistently design the system around
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* it. The OS is a toolbox that offers a lot of tools but you don't have
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* to use them all necessarily.
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*/
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/** @} */
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@ -77,7 +77,8 @@ Win32-MinGW - ChibiOS/RT simulator and demo into a WIN32 process,
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added a specific test case to the test suite (backported in stable branch).
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- FIX: Fixed a problem in time ranges (bug 2680425)(backported in stable
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branch).
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- FIX: Fixed a wrong parameter check in chVTSetI() (bug 2679155).
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- FIX: Fixed a wrong parameter check in chVTSetI() and chThdSleep()
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(bug 2679155).
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- FIX: Build error with options CH_USE_NESTED_LOCKS && !CH_OPTIMIZE_SPEED
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(bug 2678928).
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- FIX: Removed unused chSysPuts() macro (bug 2672678).
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@ -88,6 +89,7 @@ Win32-MinGW - ChibiOS/RT simulator and demo into a WIN32 process,
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- Removed testcond.c|h and moved the test cases into testmtx.c. Mutexes and
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condvars have to be tested together.
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- Added architecture diagram to the documentation.
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- Removed from the documentation some references to long gone functions...
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*** 1.1.1unstable ***
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- FIX: Fixed a problem into the STACK_ALIGN() macro (backported in stable
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14
src/chschd.c
14
src/chschd.c
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@ -122,11 +122,15 @@ static void wakeup(void *p) {
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* to sleep is awakened after the specified time has elapsed.
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*
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* @param[in] newstate the new thread state
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* @param[in] time the number of ticks before the operation timeouts,
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* the special value @p TIME_INFINITE is allowed.
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* It is not possible to specify @p TIME_IMMEDIATE as timeout
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* specification, it is interpreted as a normal time
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* specification.
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* @param[in] time the number of ticks before the operation timeouts, the
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* special values are handled as follow:
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* - @a TIME_INFINITE the thread enters an infinite sleep
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* state, this is equivalent to invoking @p chSchGoSleepS()
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* but, of course, less efficient.
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* - @a TIME_IMMEDIATE this value is accepted but interpreted
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* as a normal time specification not as an immediate timeout
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* specification.
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* .
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* @return The wakeup message.
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* @retval RDY_TIMEOUT if a timeout occurs.
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* @note The function must be called in the system mutex zone.
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@ -75,7 +75,6 @@ void chSysInit(void) {
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chSysEnable();
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/*
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* The idle thread is created using the port-provided implementation.
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* This thread has the lowest priority in the system, its role is just to
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* serve interrupts in its context while keeping the lowest energy saving
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* mode compatible with the system status.
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@ -73,10 +73,8 @@ static void memfill(uint8_t *startp, uint8_t *endp, uint8_t v) {
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*
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* @param[out] workspace pointer to a working area dedicated to the thread
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* stack
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* @param[in] wsize size of the working area.
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* @param[in] prio the priority level for the new thread. Usually the threads
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* are created with priority @p NORMALPRIO, priorities
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* can range from @p LOWPRIO to @p HIGHPRIO.
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* @param[in] wsize size of the working area
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* @param[in] prio the priority level for the new thread
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* @param[in] pf the thread function
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* @param[in] arg an argument passed to the thread function. It can be @p NULL.
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* @return The pointer to the @p Thread structure allocated for the
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@ -112,10 +110,8 @@ Thread *chThdInit(void *workspace, size_t wsize,
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*
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* @param[out] workspace pointer to a working area dedicated to the thread
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* stack
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* @param[in] wsize size of the working area.
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* @param[in] prio the priority level for the new thread. Usually the threads
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* are created with priority @p NORMALPRIO, priorities
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* can range from @p LOWPRIO to @p HIGHPRIO.
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* @param[in] wsize size of the working area
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* @param[in] prio the priority level for the new thread
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* @param[in] pf the thread function
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* @param[in] arg an argument passed to the thread function. It can be @p NULL.
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* @return The pointer to the @p Thread structure allocated for the
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@ -134,9 +130,7 @@ Thread *chThdCreateStatic(void *workspace, size_t wsize,
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* @brief Creates a new thread allocating the memory from the heap.
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*
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* @param[in] wsize size of the working area to be allocated
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* @param[in] prio the priority level for the new thread. Usually the threads
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* are created with priority @p NORMALPRIO, priorities
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* can range from @p LOWPRIO to @p HIGHPRIO.
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* @param[in] prio the priority level for the new thread
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* @param[in] pf the thread function
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* @param[in] arg an argument passed to the thread function. It can be @p NULL.
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* @return The pointer to the @p Thread structure allocated for the
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@ -168,9 +162,7 @@ Thread *chThdCreateFromHeap(size_t wsize, tprio_t prio,
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* Pool.
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*
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* @param[in] mp the memory pool
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* @param[in] prio the priority level for the new thread. Usually the threads
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* are created with priority @p NORMALPRIO, priorities
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* can range from @p LOWPRIO to @p HIGHPRIO.
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* @param[in] prio the priority level for the new thread
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* @param[in] pf the thread function
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* @param[in] arg an argument passed to the thread function. It can be @p NULL.
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* @return The pointer to the @p Thread structure allocated for the
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@ -207,7 +199,7 @@ Thread *chThdCreateFromMemoryPool(MemoryPool *mp, tprio_t prio,
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* @param[in] newprio the new priority level of the running thread
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* @return The old priority level.
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* @note The function returns the real thread priority regardless of the
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* actual priority that could be higher than the real priority because
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* current priority that could be higher than the real priority because
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* the priority inheritance mechanism.
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*/
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tprio_t chThdSetPriority(tprio_t newprio) {
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@ -268,13 +260,18 @@ void chThdTerminate(Thread *tp) {
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/**
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* @brief Suspends the invoking thread for the specified time.
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*
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* @param[in] time the delay in system ticks, the values @p TIME_IMMEDIATE and
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* @p TIME_INFINITE are not allowed
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* @param[in] time the delay in system ticks, the special values are handled as
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* follow:
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* - @a TIME_INFINITE the thread enters an infinite sleep
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* state.
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* - @a TIME_IMMEDIATE this value is accepted but interpreted
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* as a normal time specification not as an immediate timeout
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* specification.
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* .
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*/
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void chThdSleep(systime_t time) {
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chDbgCheck((time != TIME_IMMEDIATE) && (time != TIME_INFINITE),
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"chThdSleep");
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chDbgCheck(time != TIME_INFINITE, "chThdSleep");
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chSysLock();
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chThdSleepS(time);
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/** Returns the pointer to the @p Thread currently in execution.*/
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#define chThdSelf() currp
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/** Returns the thread priority.*/
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/** Returns the current thread priority.*/
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#define chThdGetPriority() (currp->p_prio)
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/** Returns the pointer to the @p Thread local storage area, if any.*/
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#define chThdLS() (void *)(currp + 1)
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/** Verifies if the specified thread is in the @p PREXIT state.*/
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/**
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* Verifies if the specified thread is in the @p PREXIT state.
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*
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* @param[in] tp the pointer to the thread
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* @retval TRUE thread terminated.
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* @retval FALSE thread not terminated.
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*/
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#define chThdTerminated(tp) ((tp)->p_state == PREXIT)
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/**
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* Verifies if the current thread has a termination request pending.
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*
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* @retval TRUE termination request pended.
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* @retval FALSE termination request not pended.
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*/
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#define chThdShouldTerminate() (currp->p_flags & P_TERMINATE)
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/**
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* Resumes a thread created with the @p P_SUSPENDED option or suspended with
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* @p chThdSuspend().
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* @param tp the pointer to the thread
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* Resumes a thread created with @p chThdInit().
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*
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* @param[in] tp the pointer to the thread
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*/
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#define chThdResumeI(tp) chSchReadyI(tp)
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/**
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* Suspends the invoking thread for the specified time.
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* @param time the delay in system ticks
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*
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* @param[in] time the delay in system ticks, the special values are handled as
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* follow:
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* - @a TIME_INFINITE the thread enters an infinite sleep
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* state.
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* - @a TIME_IMMEDIATE this value is accepted but interpreted
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* as a normal time specification not as an immediate timeout
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* specification.
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* .
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*/
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#define chThdSleepS(time) chSchGoSleepTimeoutS(PRSLEEP, time)
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/**
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* Delays the invoking thread for the specified number of seconds.
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*
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* @param[in] sec the time in seconds
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* @note The specified time is rounded up to a value allowed by the real
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* system clock.
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* @note The maximum specified value is implementation dependent.
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@ -227,6 +246,8 @@ extern "C" {
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/**
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* Delays the invoking thread for the specified number of milliseconds.
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*
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* @param[in] msec the time in milliseconds
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* @note The specified time is rounded up to a value allowed by the real
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* system clock.
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* @note The maximum specified value is implementation dependent.
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@ -235,6 +256,8 @@ extern "C" {
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/**
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* Delays the invoking thread for the specified number of microseconds.
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*
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* @param[in] usec the time in microseconds
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* @note The specified time is rounded up to a value allowed by the real
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* system clock.
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* @note The maximum specified value is implementation dependent.
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