Fix #11

src/mesh/RadioLibInterface.cpp

@@ -1,5 +1,6 @@
 #include "RadioLibInterface.h"
 #include "MeshTypes.h"
+#include "OSTimer.h"
 #include "mesh-pb-constants.h"
 #include <NodeDB.h> // FIXME, this class shouldn't need to look into nodedb
 #include <configuration.h>
@@ -89,14 +90,17 @@ bool RadioLibInterface::canSendImmediately()
     // We wait _if_ we are partially though receiving a packet (rather than just merely waiting for one).
     // To do otherwise would be doubly bad because not only would we drop the packet that was on the way in,
     // we almost certainly guarantee no one outside will like the packet we are sending.
-    PendingISR isPending = pending;
     bool busyTx = sendingPacket != NULL;
     bool busyRx = isReceiving && isActivelyReceiving();
 
-    if (busyTx || busyRx || isPending)
-        DEBUG_MSG("Can not send yet, busyTx=%d, busyRx=%d, intPend=%d\n", busyTx, busyRx, isPending);
-
-    return !busyTx && !busyRx && !isPending;
+    if (busyTx || busyRx) {
+        if (busyTx)
+            DEBUG_MSG("Can not send yet, busyTx\n");
+        if (busyRx)
+            DEBUG_MSG("Can not send yet, busyRx\n");
+        return false;
+    } else
+        return true;
 }
 
 /// Send a packet (possibly by enquing in a private fifo).  This routine will
@@ -104,8 +108,8 @@ bool RadioLibInterface::canSendImmediately()
 /// bluetooth comms code.  If the txmit queue is empty it might return an error
 ErrorCode RadioLibInterface::send(MeshPacket *p)
 {
-    DEBUG_MSG("enqueuing for send on mesh fr=0x%x,to=0x%x,id=%d\n (txGood=%d,rxGood=%d,rxBad=%d)\n", p->from, p->to, p->id,
-              txGood, rxGood, rxBad);
+    DEBUG_MSG("enqueuing for send on mesh fr=0x%x,to=0x%x,id=%d (txGood=%d,rxGood=%d,rxBad=%d)\n", p->from, p->to, p->id, txGood,
+              rxGood, rxBad);
     ErrorCode res = txQueue.enqueue(p, 0) ? ERRNO_OK : ERRNO_UNKNOWN;
 
     if (res != ERRNO_OK) { // we weren't able to queue it, so we must drop it to prevent leaks
@@ -113,7 +117,9 @@ ErrorCode RadioLibInterface::send(MeshPacket *p)
         return res;
     }
 
-    startTransmitTimer(false); // We want all sending/receiving to be done by our daemon thread
+    // We want all sending/receiving to be done by our daemon thread, We use a delay here because this packet might have been sent
+    // in response to a packet we just received.  So we want to make sure the other side has had a chance to reconfigure its radio
+    startTransmitTimer(true);
 
     return res;
 }
@@ -127,6 +133,19 @@ bool RadioLibInterface::canSleep()
     return res;
 }
 
+/** At the low end we want to pick a delay large enough that anyone who just completed sending (some other node)
+ * has had enough time to switch their radio back into receive mode.
+ */
+#define MIN_TX_WAIT_MSEC 100
+
+/**
+ * At the high end, this value is used to spread node attempts across time so when they are replying to a packet
+ * they don't both check that the airwaves are clear at the same moment.  As long as they are off by some amount
+ * one of the two will be first to start transmitting and the other will see that.  I bet 500ms is more than enough
+ * to guarantee this.
+ */
+#define MAX_TX_WAIT_MSEC 2000 // stress test would still fail occasionally with 1000
+
 /** radio helper thread callback.
 
 We never immediately transmit after any operation (either rx or tx).  Instead we should start receiving and
@@ -138,7 +157,7 @@ and then they will wait until that packet finishes.
 NOTE: the large flood rebroadcast delay might still be needed even with this approach.  Because we might not be able to hear other
 transmitters that we are potentially stomping on.  Requires further thought.
 
-FIXME, the 50ms and 200ms values should be tuned via logic analyzer later.
+FIXME, the MIN_TX_WAIT_MSEC and MAX_TX_WAIT_MSEC values should be tuned via logic analyzer later.
 */
 void RadioLibInterface::loop()
 {
@@ -162,8 +181,6 @@ void RadioLibInterface::loop()
             if (!canSendImmediately()) {
                 startTransmitTimer(); // try again in a little while
             } else {
-                DEBUG_MSG("Transmit timer completed!\n");
-
                 // Send any outgoing packets we have ready
                 MeshPacket *txp = txQueue.dequeuePtr(0);
                 assert(txp);
@@ -176,9 +193,11 @@ void RadioLibInterface::loop()
     }
 }
 
-#include "OSTimer.h"
+#ifndef NO_ESP32
+#define USE_HW_TIMER
+#endif
 
-void RadioLibInterface::timerCallback(void *p1, uint32_t p2)
+void IRAM_ATTR RadioLibInterface::timerCallback(void *p1, uint32_t p2)
 {
     RadioLibInterface *t = (RadioLibInterface *)p1;
 
@@ -186,7 +205,17 @@ void RadioLibInterface::timerCallback(void *p1, uint32_t p2)
 
     // We use without overwrite, so that if there is already an interrupt pending to be handled, that gets handle properly (the
     // ISR handler will restart our timer)
+#ifndef USE_HW_TIMER
     t->notify(TRANSMIT_DELAY_COMPLETED, eSetValueWithoutOverwrite);
+#else
+    BaseType_t xHigherPriorityTaskWoken;
+    instance->notifyFromISR(&xHigherPriorityTaskWoken, TRANSMIT_DELAY_COMPLETED, eSetValueWithoutOverwrite);
+
+    /* Force a context switch if xHigherPriorityTaskWoken is now set to pdTRUE.
+    The macro used to do this is dependent on the port and may be called
+    portEND_SWITCHING_ISR. */
+    YIELD_FROM_ISR(xHigherPriorityTaskWoken);
+#endif
 }
 
 void RadioLibInterface::startTransmitTimer(bool withDelay)
@@ -194,8 +223,15 @@ void RadioLibInterface::startTransmitTimer(bool withDelay)
     // If we have work to do and the timer wasn't already scheduled, schedule it now
     if (!timerRunning && !txQueue.isEmpty()) {
         timerRunning = true;
-        uint32_t delay = withDelay ? 0 : random(50, 200); // See documentation for loop() wrt these values
-        scheduleCallback(timerCallback, this, 0, delay);
+        uint32_t delay =
+            !withDelay ? 0 : random(MIN_TX_WAIT_MSEC, MAX_TX_WAIT_MSEC); // See documentation for loop() wrt these values
+                                                                         // DEBUG_MSG("xmit timer %d\n", delay);
+#ifdef USE_HW_TIMER
+        bool okay = scheduleHWCallback(timerCallback, this, 0, delay);
+#else
+        bool okay = scheduleOSCallback(timerCallback, this, 0, delay);
+#endif
+        assert(okay);
     }
 }
 
@@ -245,6 +281,7 @@ void RadioLibInterface::handleReceiveInterrupt()
             const PacketHeader *h = (PacketHeader *)radiobuf;
             uint8_t ourAddr = nodeDB.getNodeNum();
 
+            rxGood++;
             if (h->to != 255 && h->to != ourAddr) {
                 DEBUG_MSG("ignoring packet not sent to us\n");
             } else {
@@ -264,7 +301,6 @@ void RadioLibInterface::handleReceiveInterrupt()
                 } else {
                     // parsing was successful, queue for our recipient
                     mp->has_payload = true;
-                    rxGood++;
                     DEBUG_MSG("Lora RX interrupt from=0x%x, id=%u\n", mp->from, mp->id);
 
                     deliverToReceiver(mp);
@@ -277,6 +313,9 @@ void RadioLibInterface::handleReceiveInterrupt()
 /** start an immediate transmit */
 void RadioLibInterface::startSend(MeshPacket *txp)
 {
+    DEBUG_MSG("Starting low level send from=0x%x, id=%u!\n", txp->from, txp->id);
+    setStandby(); // Cancel any already in process receives
+
     size_t numbytes = beginSending(txp);
 
     int res = iface->startTransmit(radiobuf, numbytes);