X-Git-Url: https://oss.titaniummirror.com/gitweb/?a=blobdiff_plain;f=tos%2Fchips%2Fmsp430%2Fusci%2FMsp430UartP.nc;h=a35dd92eb8d4b05a2296b1612ecde05f79d30b44;hb=dfbae4ae464c8990d122cc07951edcdbc1983ac4;hp=1b595bfdbd9af40369beceb8128264f6f6620183;hpb=0290d9081acdbe813926612478fbe81e7a44e3c5;p=tinyos-2.x.git

diff --git a/tos/chips/msp430/usci/Msp430UartP.nc b/tos/chips/msp430/usci/Msp430UartP.nc
index 1b595bfd..a35dd92e 100644
--- a/tos/chips/msp430/usci/Msp430UartP.nc
+++ b/tos/chips/msp430/usci/Msp430UartP.nc
@@ -26,7 +26,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
  * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
- 
+
 /**
  * Uart implementation using a USCI device.
  *
@@ -35,7 +35,7 @@
  *
  * @author R. Steve McKown <rsmckown@gmail.com>
  */
- 
+
 generic module Msp430UartP() {
   provides {
     interface UartStream;
@@ -104,6 +104,10 @@ implementation {
 	call TXD.selectModuleFunc();
       }
 
+      /* Reset important state variables */
+      m_robuf = 0;
+      m_sobuf = 0;
+
       /* Clear interrupts; we'll add them as needed */
       call Registers.clrIeRx();
       call Registers.clrIeTx();
@@ -124,6 +128,10 @@ implementation {
       call Registers.clrIeTx();
       call Registers.clrIfgRx();
 
+      /* Reset important state variables */
+      m_robuf = 0;
+      m_sobuf = 0;
+
       /* Restore pins to their pre-configure state */
       if (m_pins & PINS_RXD)
 	call RXD.selectIOFunc();
@@ -134,10 +142,7 @@ implementation {
 
   async command error_t UartByte.send(uint8_t byte)
   {
-    /* FIXME: race with UartStream.send() */
     atomic {
-      if (m_sobuf)
-	return FAIL;
       while (!call Registers.getIfgTx());
       call Registers.setTxbuf(byte);
       return SUCCESS;
@@ -149,29 +154,30 @@ implementation {
     atomic {
       if (m_sobuf || !buf || !len)
 	return FAIL;
-      m_sobuf = buf;
-      m_solen = len;
-      while (!call Registers.getIfgTx());
+      m_sbuf = m_sobuf = buf;
+      m_slen = m_solen = len;
       call Registers.setIeTx();
-      call Registers.setTxbuf(*m_sobuf);
-      m_slen = m_solen - 1;
-      if (m_slen)
-	m_sbuf = m_sobuf + 1;
       return SUCCESS;
     }
   }
 
   async event void Interrupts.tx()
   {
-    while (m_slen && call Registers.getIfgTx()) {
-      call Registers.setTxbuf(*m_sbuf);
-      if (--m_slen)
-	m_sbuf++;
-    }
-    if (m_slen == 0 && m_sobuf) {
-      call Registers.clrIeTx();
-      m_sobuf = 0;
-      signal UartStream.sendDone(m_sobuf, m_solen, SUCCESS);
+    /* FIXME: this can cause an arbitrarily long ISR, if m_slen is large.
+     * But depending on timing, we may always only write 1 byte.
+     */
+    if (m_sobuf) {
+      while (!call Registers.getIfgTx()); /* in case interleaved UB.send */
+      while (m_slen && call Registers.getIfgTx()) {
+	call Registers.setTxbuf(*m_sbuf);
+	if (--m_slen)
+	  m_sbuf++;
+      }
+      if (m_slen == 0) {
+	call Registers.clrIeTx();
+	m_sobuf = 0;
+	signal UartStream.sendDone(m_sobuf, m_solen, SUCCESS);
+      }
     }
   }
 
@@ -236,30 +242,31 @@ implementation {
 
   async event void Interrupts.rx(uint8_t byte)
   {
-    atomic {
-      if (m_robuf) {
-	/* receive() takes precedence if active */
-	while (m_rlen && call Registers.getIfgRx()) {
-	  *m_rbuf = byte;
-	  if (--m_rlen)
-	    m_rbuf++;
-	}
-	if (m_rlen == 0 && m_robuf) {
-	  if (m_rxie) {
-	    call Registers.clrIeRx();
-	    call Registers.clrIfgRx();
-	  }
-	  m_robuf = 0;
-	  signal UartStream.receiveDone(m_robuf, m_rolen, SUCCESS);
+    if (m_robuf) {
+      /* receive() takes precedence if active */
+      /* FIXME: an arbitrarily long ISR may occur if m_rlen is large.
+       * But depending on timing, we may always only read 1 byte.
+       */
+      while (m_rlen && call Registers.getIfgRx()) {
+	*m_rbuf = byte;
+	if (--m_rlen)
+	  m_rbuf++;
+      }
+      if (m_rlen == 0 && m_robuf) {
+	if (m_rxie) {
+	  call Registers.clrIeRx();
+	  call Registers.clrIfgRx();
 	}
-      } else
-	signal UartStream.receivedByte(byte);
-    }
+	m_robuf = 0;
+	signal UartStream.receiveDone(m_robuf, m_rolen, SUCCESS);
+      }
+    } else
+      signal UartStream.receivedByte(byte);
   }
 
   default async command const msp430_usci_uart_t* Configure.get()
   {
-    const static msp430_usci_uart_t def = { 
+    const static msp430_usci_uart_t def = {
       ctl0: UCMODE_0,		/* async, lsb first, 8N1 */
       ctl1: UCSWRST | UCSSEL_3,	/* clock uart from SMCLK */
       brx: UBRX_1MHZ_115200,