Merge TinyOS 2.1.1 into master.

[tinyos-2.x.git] / tos / chips / msp430 / usci / Msp430UartP.nc

diff --git a/tos/chips/msp430/usci/Msp430UartP.nc b/tos/chips/msp430/usci/Msp430UartP.nc
index 742c167470cd62d73fda661f01ead91cf509c93a..72df1df0c1827f63ef14f7836a5927aaa43b3828 100644 (file)
--- 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;
@@ -134,10 +134,7 @@ 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;
@@ -149,26 +146,25 @@ 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()
   {
+    /* FIXME: this can cause an arbitrarily long ISR, if m_slen is large.
+     * But depending on timing, we may always only write 1 byte.
+     */
+    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 && m_sobuf) {
+    if (m_slen == 0) {
       call Registers.clrIeTx();
       m_sobuf = 0;
       signal UartStream.sendDone(m_sobuf, m_solen, SUCCESS);
@@ -238,6 +234,9 @@ implementation {
   {
     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)
@@ -257,7 +256,7 @@ implementation {
 
   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,