IOSerialStream.cpp

00001 /* IOSerialStream.cpp */
00002 /* Copyright (C) 2012 mbed.org, MIT License
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
00005  * and associated documentation files (the "Software"), to deal in the Software without restriction,
00006  * including without limitation the rights to use, copy, modify, merge, publish, distribute,
00007  * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
00008  * furnished to do so, subject to the following conditions:
00009  *
00010  * The above copyright notice and this permission notice shall be included in all copies or
00011  * substantial portions of the Software.
00012  *
00013  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
00014  * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00015  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
00016  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00017  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00018  */
00019 
00020 #define __DEBUG__ 0 //Maximum verbosity
00021 #ifndef __MODULE__
00022 #define __MODULE__ "IOSerialStream.cpp"
00023 #endif
00024 
00025 #include "core/fwk.h"
00026 
00027 #include <cstring>
00028 
00029 #include "IOSerialStream.h"
00030 
00031 IOSerialStream::IOSerialStream(mbed::Serial& serial) : m_serial(serial), m_serialTxFifoEmpty(true),
00032 m_availableSphre(1), m_spaceSphre(1), m_inBuf(), m_outBuf()
00033 {
00034   m_availableSphre.wait();
00035   m_spaceSphre.wait();
00036   //Attach interrupts
00037   m_serial.attach(this, &IOSerialStream::readable, mbed::Serial::RxIrq);
00038   m_serial.attach(this, &IOSerialStream::writeable, mbed::Serial::TxIrq);
00039 }
00040 
00041 /*virtual*/ IOSerialStream::~IOSerialStream()
00042 {
00043   m_serial.attach(NULL, mbed::Serial::RxIrq);
00044   m_serial.attach(NULL, mbed::Serial::TxIrq);
00045 }
00046 
00047 //0 for non-blocking (returns immediately), osWaitForever for infinite blocking
00048 /*virtual*/ int IOSerialStream::read(uint8_t* buf, size_t* pLength, size_t maxLength, uint32_t timeout/*=osWaitForever*/)
00049 {
00050   DBG("Trying to read at most %d chars", maxLength);
00051   int ret = waitAvailable(timeout);
00052   if(ret)
00053   {
00054     WARN("Error %d while waiting for incoming data", ret);
00055     return ret;
00056   }
00057   int readLen = MIN( available(), maxLength );
00058   *pLength = readLen;
00059   setupReadableISR(false);
00060   while(readLen--)
00061   {
00062     m_inBuf.dequeue(buf);
00063     buf++;
00064   }
00065   setupReadableISR(true);
00066   DBG("Read %d chars successfully", *pLength);
00067   return OK;
00068 }
00069 
00070 /*virtual*/ size_t IOSerialStream::available()
00071 {
00072   setupReadableISR(false); //m_inBuf.available() is not reentrant
00073   size_t len = m_inBuf.available();
00074   setupReadableISR(true);
00075   return len;
00076 }
00077 
00078 /*virtual*/ int IOSerialStream::waitAvailable(uint32_t timeout/*=osWaitForever*/) //Wait for data to be available
00079 {
00080   int ret;
00081   if(available()) //Is data already available?
00082   {
00083     m_availableSphre.wait(0); //Clear the queue as data is available
00084     return OK;
00085   }
00086 
00087   DBG("Waiting for data availability %d ms (-1 is infinite)", timeout);
00088   ret = m_availableSphre.wait(timeout); //Wait for data to arrive or for abort
00089   if(ret <= 0)
00090   {
00091     DBG("Timeout");
00092     return NET_TIMEOUT;
00093   }
00094   if(!available()) //Even if abort has been called, return that data is available
00095   {
00096     DBG("Aborted");
00097     return NET_INTERRUPTED;
00098   }
00099   DBG("Finished waiting");
00100   m_availableSphre.wait(0); //Clear the queue as data is available
00101   return OK;
00102 }
00103 
00104 /*virtual*/ int IOSerialStream::abortRead() //Abort current reading (or waiting) operation
00105 {
00106   if( !available() ) //If there is data pending, no need to abort
00107   {
00108     m_availableSphre.release(); //Force exiting the waiting state; kludge to pass a RC directly
00109   }
00110   else
00111   {
00112     DBG("Serial is readable"); ;
00113   }
00114   return OK;
00115 }
00116 
00117 void IOSerialStream::setupReadableISR(bool en)
00118 {
00119   if(en)
00120   {
00121     ((LPC_UART_TypeDef *)(UART_3))->IER |= 1 << 0;
00122   }
00123   else
00124   {
00125     ((LPC_UART_TypeDef *)(UART_3))->IER &= ~(1 << 0);
00126   }
00127 }
00128 
00129 void IOSerialStream::readable() //Callback from m_serial when new data is available
00130 {
00131   do
00132   {
00133     m_inBuf.queue(((LPC_UART_TypeDef *)UART_3)->RBR); //FIXME mbed libraries this is an awful kludge
00134   } while(m_serial.readable());
00135   m_availableSphre.release(); //Force exiting the waiting state
00136 }
00137 
00138 //0 for non-blocking (returns immediately), osWaitForever for infinite blocking
00139 /*virtual*/ int IOSerialStream::write(uint8_t* buf, size_t length, uint32_t timeout/*=osWaitForever*/)
00140 {
00141   DBG("Trying to write %d chars", length);
00142   int ret = waitSpace(timeout);
00143   if(ret)
00144   {
00145     WARN("Error %d while waiting for space", ret);
00146     return ret;
00147   }
00148   DBG("Writing %d chars", length);
00149   setupWriteableISR(false);
00150   while(length)
00151   {
00152     m_outBuf.queue(*buf);
00153     buf++;
00154     length--;
00155     if(length && !space())
00156     {
00157       DBG("Waiting to write remaining %d chars", length);
00158       setupWriteableISR(true);
00159       ret = waitSpace(timeout);
00160       if(ret)
00161       {
00162         WARN("Error %d while waiting for space", ret);
00163         return ret;
00164       }
00165       setupWriteableISR(false);
00166     }
00167   }
00168   //If m_serial tx fifo is empty we need to manually tx a byte in order to trigger the interrupt
00169   if( m_outBuf.available() && m_serialTxFifoEmpty )
00170   {
00171     m_serialTxFifoEmpty = false;
00172     uint8_t c;
00173     m_outBuf.dequeue(&c);
00174     //m_serial.putc((char)c);
00175     ((LPC_UART_TypeDef *)UART_3)->THR = c; //FIXME awful kludge
00176   }
00177   setupWriteableISR(true);
00178   DBG("Write successful");
00179   return OK;
00180 }
00181 
00182 /*virtual*/ size_t IOSerialStream::space()
00183 {
00184   setupWriteableISR(false); //m_outBuf.available() is not reentrant
00185   size_t len = CIRCBUF_SIZE - m_outBuf.available();
00186   setupWriteableISR(true);
00187   return len;
00188 }
00189 
00190 /*virtual*/ int IOSerialStream::waitSpace(uint32_t timeout/*=osWaitForever*/) //Wait for space to be available
00191 {
00192   int ret;
00193   if(space()) //Is still space already left?
00194   {
00195     m_spaceSphre.wait(0); //Clear the queue as space is available
00196     return OK;
00197   }
00198 
00199   DBG("Waiting for data space %d ms (-1 is infinite)", timeout);
00200   ret = m_spaceSphre.wait(timeout); //Wait for space to be made or for abort
00201   if(ret <= 0)
00202   {
00203     DBG("Timeout");
00204     return NET_TIMEOUT;
00205   }
00206   if(!space()) //Even if abort has been called, return that space is available
00207   {
00208     DBG("Aborted");
00209     return NET_INTERRUPTED;
00210   }
00211   m_spaceSphre.wait(0); //Clear the queue as space is available
00212   return OK;
00213 }
00214 
00215 /*virtual*/ int IOSerialStream::abortWrite() //Abort current writing (or waiting) operation
00216 {
00217   if( !space() ) //If there is space left, no need to abort
00218   {
00219     m_spaceSphre.release(); //Force exiting the waiting state
00220   }
00221   return OK;
00222 }
00223 
00224 void IOSerialStream::setupWriteableISR(bool en)
00225 {
00226   if(en)
00227   {
00228     ((LPC_UART_TypeDef *)(UART_3))->IER |= 1 << 1;
00229   }
00230   else
00231   {
00232     ((LPC_UART_TypeDef *)(UART_3))->IER &= ~(1 << 1);
00233   }
00234 }
00235 
00236 void IOSerialStream::writeable() //Callback from m_serial when new space is available
00237 {
00238   if(m_outBuf.isEmpty())
00239   {
00240     m_serialTxFifoEmpty = true;
00241   }
00242   else
00243   {
00244     while(m_serial.writeable() && !m_outBuf.isEmpty())
00245     {
00246       uint8_t c;
00247       m_outBuf.dequeue(&c);
00248       //m_serial.putc((char)c);
00249       ((LPC_UART_TypeDef *)UART_3)->THR = c; //FIXME awful kludge
00250     }
00251   }
00252   m_spaceSphre.release(); //Force exiting the waiting state
00253 }